Download Hi-Res ImageDownload to MS-PowerPointCite This:ACS Omega 2021, 6, 30, 19876-19882

ArticleJuly 23, 2021

Rice Cd Levels in Cambodia Ranged 3 Orders of Magnitude due to Season and Soil Cd Levels
Click to copy article linkArticle link copied!

Ruifang Hu
Ruifang Hu
Department of Plant and Soil Sciences, University of Delaware, Newark, Delaware 19716, United States
More by Ruifang Hu
Angelia L. Seyfferth*
Angelia L. Seyfferth
Department of Plant and Soil Sciences, University of Delaware, Newark, Delaware 19716, United States
*Email: [email protected]
More by Angelia L. Seyfferth
https://orcid.org/0000-0003-3589-6815

Open PDF

ACS Omega

Cite this: ACS Omega 2021, 6, 30, 19876–19882

Click to copy citationCitation copied!

https://doi.org/10.1021/acsomega.1c02741

Published July 23, 2021

CC-BY-NC-ND 4.0 .

Abstract

Click to copy section linkSection link copied!

Cadmium (Cd) is a toxic trace element that can be transported from soil into rice grain, posing health threats to rice consumers. Among the global studies on rice grain Cd, only one market survey reported grain Cd levels from Cambodia, an important rice-growing country in Southeast Asia. Here, we collected paired rice and soil samples in the wet and dry seasons from major rice-growing regions across five provinces in Cambodia and report the relationships between plant Cd and soil Cd parameters. Both DTPA-extractable and nitric acid digestible soil Cd are significant predictors for Cd levels in rice straw and grain. Rice grain Cd concentrations ranged 3 orders of magnitude from 0.002 to 1.066 mg kg^–1 with the median and mean concentrations of 0.024 and 0.091 mg kg^–1, respectively; these values have an upper range that is higher than previously reported. The highest grain Cd levels were found in rice grown in the dry season from two provinces located southeast of Phnom Penh along the Lower Mekong River, and their corresponding soil Cd levels were relatively higher than those collected during the wet season and around the Tonle Sap. While the source of higher Cd may be geogenic or due to anthropogenic activities, our data demonstrate that geographical and perhaps seasonal differences in grain Cd exist even within a small country that might not be reflected in market surveys.

This publication is licensed under

CC-BY-NC-ND 4.0 .

License Summary*
You are free to share(copy and redistribute) this article in any medium or format within the parameters below:
- Creative Commons (CC): This is a Creative Commons license.
- Attribution (BY): Credit must be given to the creator.
- Non-Commercial (NC): Only non-commercial uses of the work are permitted.
- No Derivatives (ND): Derivative works may be created for non-commercial purposes, but sharing is prohibited.
View full license
*Disclaimer
This summary highlights only some of the key features and terms of the actual license. It is not a license and has no legal value. Carefully review the actual license before using these materials.
License Summary*
You are free to share(copy and redistribute) this article in any medium or format within the parameters below:
- Creative Commons (CC): This is a Creative Commons license.
- Attribution (BY): Credit must be given to the creator.
- Non-Commercial (NC): Only non-commercial uses of the work are permitted.
- No Derivatives (ND): Derivative works may be created for non-commercial purposes, but sharing is prohibited.
View full license
*Disclaimer
This summary highlights only some of the key features and terms of the actual license. It is not a license and has no legal value. Carefully review the actual license before using these materials.
License Summary*
You are free to share(copy and redistribute) this article in any medium or format within the parameters below:
- Creative Commons (CC): This is a Creative Commons license.
- Attribution (BY): Credit must be given to the creator.
- Non-Commercial (NC): Only non-commercial uses of the work are permitted.
- No Derivatives (ND): Derivative works may be created for non-commercial purposes, but sharing is prohibited.
View full license
*Disclaimer
This summary highlights only some of the key features and terms of the actual license. It is not a license and has no legal value. Carefully review the actual license before using these materials.
License Summary*
You are free to share(copy and redistribute) this article in any medium or format within the parameters below:
- Creative Commons (CC): This is a Creative Commons license.
- Attribution (BY): Credit must be given to the creator.
- Non-Commercial (NC): Only non-commercial uses of the work are permitted.
- No Derivatives (ND): Derivative works may be created for non-commercial purposes, but sharing is prohibited.
View full license
*Disclaimer
This summary highlights only some of the key features and terms of the actual license. It is not a license and has no legal value. Carefully review the actual license before using these materials.

Subjects

Introduction

Click to copy section linkSection link copied!

Cd is a toxic heavy metal and group I carcinogen that has a long biological half-life in humans and can cause kidney damage, cancer, osteoporosis, and cardiovascular disease. (1−5) Cd intake through food consumption is the major route for non-smokers, and rice in particular represents a significant portion because of its role as a staple food for billions of people. (6) Micronutrient (e.g., Fe, Zn, and Ca) deficiency can lead to more Cd absorption by rats or humans, (7−9) and white rice is typically low in these micronutrients. Historical rice Cd toxicity cases include itai–itai disease in Japan, which was caused by consumption of rice with high Cd content due to industrial Cd contamination in a rice-growing region. (10) The prevalence of Cd accumulation in rice is less-well studied compared to other contaminants (e.g., arsenic).

Cd is naturally present in soil at low background concentrations ranging from <0.1 to 2.0 mg kg^–1, (9) but levels can be higher due to industrial release and deposition (11,12) and soil application of P fertilizer that has Cd impurity. (13) Regardless of the source, Cd can be solubilized depending on soil conditions. Cd mostly exists in soil solution in its divalent cationic form, and higher soil cation exchange capacity (CEC) enhances soil Cd retention and thus decreases Cd plant availability. (14) Cd is more plant available under highly weathered, acidic soil because Cd tends to precipitate as Cd(OH)₂ or CdCO₃ at higher pH. (15,16) However, in paddy soils where soil flooding buffers pH to near neutral, redox has an indirect control on Cd plant availability. Under flooded paddy conditions, Cd tends to precipitate as sparingly soluble CdS, but it can be mobilized under more oxic conditions when S^2– oxidizes to SO₄^2–. (17,18) If this occurs in highly weathered and acidic paddy soil, Cd²⁺ is available for plant uptake. It is therefore important to understand how water availability, soil Cd levels, and soil chemical factors affect grain Cd concentrations.

Some rice-producing regions may be prone to high grain Cd levels either due to proximity to industrial activities or because of rice production with less soil flooding, but little is known about Cambodia. For example, elevated rice Cd are found in metal-mining areas in parts of Hunan (19) and Guangdong (20,21) China, but no studies have reported geographical variation in Cambodia where rice is a major domestic crop and comprises over 70% of daily caloric intake. In addition, rice grown with limited water (i.e., higher soil Eh values) leads to higher rice grain Cd concentrations, which has been reported in multiple studies in China and Japan (17,22,23) but not in Cambodia. The tropical monsoonal climate brings Cambodia distinct wet and dry seasons, with a wet season typically from May to mid-November and the dry season from mid-November to April. Due to the limited irrigation infrastructure, Cambodian rice is typically grown in the floodplain of the Tonle Sap that swells during the wet season, but some rice is grown in the dry season along the Lower Mekong River. Therefore, rice grain Cd may be elevated in dry season Cambodian rice due to limited water availability and/or local droughts. However, to our knowledge, there is only one study that reports grain Cd levels from Cambodia; this market survey showed low grain Cd levels that ranged from 0.001 to 0.03 mg kg^–1 based on 14 samples. (24) While market surveys are informative, there is often missing information about the timing (i.e., wet or dry season) and location (i.e., soil conditions) and of plant growth, which limits our understanding of the edaphic factors that influence the plant Cd levels. The soils of the rice-growing region in Cambodia are mostly highly weathered soil developed from old and recent alluvium or underlying parent material and are generally acidic with low soil organic matter (SOM) and CEC. (25) These soil conditions are likely to increase the plant availability of Cd particularly in the dry season, but there have been no reports of paired soil and rice samples across seasons from Cambodia.

Here, we examined the Cd content in rice grain, straw, and paddy soil, which were sampled in the wet or dry season from five major rice-growing provinces in Cambodia. We hypothesized that dry season rice would contain higher grain Cd than wet season rice in Cambodia due to the less water available for rice, which would result in more oxidizing soil conditions and higher plant-available Cd in the acidic soils. We further hypothesized that plant Cd concentrations would be positively correlated with soil Cd concentrations and negatively correlated with soil pH and CEC.

Results

Click to copy section linkSection link copied!

Rice Grain, Rice Straw, and Soil Cd Concentrations

The rice Cd levels from Cambodia varied by province and season (Figure 1). Unpolished rice grain Cd concentrations ranged from 0.002 to 1.066 mg kg^–1, with a median concentration of 0.024 mg kg^–1. The mean of grain Cd of samples collected in wet and dry seasons was 0.018 ± 0.011 mg kg^–1 (n = 18) and 0.196 ± 0.15 mg kg^–1 (n = 12), respectively. Kampong Thom had the lowest grain Cd concentration of 0.002 mg kg^–1, but only one sample was collected from this province. Banteay Meanchey (wet season) had relatively low grain Cd concentration with a mean of 0.016 ± 0.014 mg kg^–1 (n = 8), and Prey Veng (dry season) had the highest mean of 0.258 ± 0.291 mg kg^–1 (n = 6). Rice straw Cd ranged from below detection to 1.95 mg kg^–1, and the median concentration was 0.098 mg kg^–1. The mean straw Cd was 0.056 ± 0.033 mg kg^–1 (n = 11) for samples collected in the wet season and was 0.414 ± 0.500 mg kg^–1 (n = 16) for those collected in the dry season (Table 1).

Figure 1. Rice grain Cd concentrations by province and season. Blue and gray broken lines represent the rice Cd limit for a 65 kg adult who consumes 450 g rice per day by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) (5.8 μg kg^–1 body weight per week) or US Agency for Toxic Substances and Diseases Registry (ATSDR) (0.7 μg kg^–1 body weight per week), respectively.

Table 1. Grain, Straw, and Soil Cd Concentrations and Soil pH, CEC, and Organic Matter Content^a

		grain	straw	soil-HNO₃ digestible	soil-DTPA extractable
sampling time	sample ID	----------------------------------mg kg^–1 Cd----------------------------------				soil pH	soil CEC meq 100g^–1	SOM % by LOI
March	KD-1	0.274	0.568	0.125	0.066	6.4	12.3	2.7
	KD-2	0.191	0.556	0.175	ns	ns	Ns	4.8
	KD-3	0.266	0.698	Ns	ns	ns	Ns	ns
	KD-4	0.014	0.029	0.185	ns	ns	11.4	3.8
	KD-5	0.034	0.109	0.198	ns	ns	Ns	5.1
	KD-6	0.024	0.051	0.185	ns	ns	Ns	6.1
	PV-1	ns	1.95	0.174	0.089	5.7	9.2	5.0
	PV-2	ns	0.5	0.214	0.107	5.4	7.2	4.1
	PV-3	ns	0.075	0.196	ns	ns	11.1	4.3
	PV-4	1.066	ns	0.14	0.068	6.3	6.1	2.7
	PV-5	0.111	0.281	Ns	ns	ns	Ns	ns
	PV-6	0.078	ns	ns	ns	ns	Ns	ns
	PV-7	0.15	0.348	0.209	0.108	7.6	10.7	3.2
	PV-8	0.126	0.107	ns	ns	ns	Ns	ns
	PV-9	0.015	0.108	ns	ns	ns	Ns	ns
	Mean	0.196	0.414	0.180	0.088	6.3	9.7	4.2
	Median	0.119	0.281	0.185	0.089	6.3	10.7	4.2
August	K Thom-1	0.002	bdl	0.007	0.005	6.9	8.9	3.5
	Ban M-1	0.068	0.174	0.05	0.014	6.7	14.1	4.3
	Ban M-2	0.023	0.034	0.022	0.009	6.8	22.9	4.6
	Ban M-3	0.004	0.009	0.016	0.005	6.1	18.5	3.7
	Ban M-4	0.003	0.008	0.017	0.006	6.1	17.7	4.3
	Ban M-5	0.004	0.013	0.015	0.005	5.9	Ns	5.1
	Ban M-6	0.002	bdl	0.019	0.006	5.9	21.7	4.4
	Ban M-7	ns	0.029	0.015	ns	ns	25.8	5.1
	Ban M-8	0.025	0.054	0.007	0.002	6	4.8	2.1
	Ban M-9	0.002	bdl	0.01	0.004	6.4	6.3	3.3
	Bat-1	0.032	0.017	0.022	0.01	5	12.5	4.0
	Bat-2	0.005	ns	ns	ns	ns	Ns	ns
	Bat-3	0.002	bdl	0.014	0.002	6.3	16.7	3.0
	Bat-4	0.002	bdl	0.01	0.004	7	15.4	2.7
	Bat-5	0.019	0.055	0.017	0.007	5	17.7	3.9
	Bat-6	0.009	ns	ns	ns	ns	Ns	ns
	Bat-7	ns	bdl	ns	ns	ns	Ns	ns
	Bat-8	ns	bdl	0.029	0.006	8.2	37.5	3.1
	Bat-9	ns	bdl	0.029	0.008	5.8	Ns	4.9
	Bat-10	0.087	0.139	ns	ns	ns	Ns	ns
	Bat-11	0.003	bdl	0.025	0.005	5	Ns	4.6
	Bat-12	0.04	0.088	0.033	0.011	5.7	21	3.0
	Mean	0.018	0.056	0.020	0.006	6.2	17.4	3.9
	Median	0.005	0.034	0.017	0.006	6.1	17.7	3.9
All	Mean	0.091	0.25	0.075	0.024	6.2	14.8	4.0
	Median	0.024	0.098	0.025	0.006	6.1	12.5	4.0

^{^a}

ns = no sample; bdl = below detection limit.

Soil physicochemical factors varied by province and season (Table 1). Soil DTPA-extractable Cd concentrations ranged from 0.002 to 0.109 mg kg^–1 with a median of 0.006 and a mean of 0.024 ± 0.015 mg kg^–1 (n = 22). The mean DTPA-extractable Cd of dry season soils was 0.088 ± 0.016 mg kg^–1 (n = 5), and the mean of wet season soils was 0.006 ± 0.001 mg kg^–1 (n = 17). Soil HNO₃-digestible Cd concentrations ranged from 0.007 to 0.214 mg kg^–1 with a median of 0.025 mg kg^–1 and a mean of 0.075 mg kg^–1. The mean of dry season soils was 0.180 ± 0.017 mg kg^–1 (n = 10), and the mean of wet season soils was 0.020 ± 0.005 mg kg^–1 (n = 18). Soil CEC ranged from 4.8 to 37.5 m eq 100 g^–1 with a median of 12.5 and a mean of 14.8, with a dry season mean of 9.7 ± 1.6 m eq 100 g^–1 (n = 7) and a wet season mean of 17.4 ± 3.8 m eq 100 g^–1 (n = 16). Neither soil pH nor SOM had distinct seasonal patterns. Soil pH ranged from 5.0 to 8.2 with a median of 6.1 and a mean of 6.2, and SOM ranged from 2.1 to 6.1% with both median and mean of 4.0% (Table 1).

Relation between Plant Cd and Soil Parameters

Regression analyses were performed between grain and/or straw Cd and measured soil parameters. The logarithms of grain (R² = 0.71, p < 0.0001) and straw (R² = 0.44, p = 0.04) Cd were positively correlated with the logarithm of DTPA-extractable soil Cd, and the logarithms of grain (R² = 0.42, p = 0.001) and straw (R² = 0.44, p = 0.02) Cd were positively correlated with the logarithm of acid-digestible soil Cd concentrations (Figure 2). No significant relationships were found between grain or straw Cd and soil pH or CEC (Figure 3). Significant positive linear relationships were also observed between the grain Cd and straw Cd (R² = 0.93, P < 0.0001) and soil DTPA-extractable Cd and soil nitric acid digestible Cd (R² = 0.99, P < 0.0001). We performed multiple linear regression and principal component analysis with our data, and these analyses confirmed that total Cd and DTPA-extractable Cd were the significant predictors of plant Cd levels (data not shown).

Figure 2. Relationships between the logarithms of grain Cd and soil DTPA-extractable Cd (a) or soil acid digestible Cd (b), and straw Cd and soil DTPA-extractable Cd (c) or soil acid digestible Cd (d). Note that the samples collected during the wet season are shown in blue and those collected during the dry season are shown in orange.

Figure 3. Relationships between grain Cd and soil pH (a) or soil CEC (b), straw Cd and soil pH (c), or soil CEC (d). None of these correlations were statistically significant. Note that the samples collected during the wet season are shown in blue and those collected during the dry season are shown in orange.

Discussion

Click to copy section linkSection link copied!

Despite the heavy reliance on rice both in production and food supply in Cambodia, to our knowledge, only one study has reported Cd levels in market-surveyed rice (24) and none has reported paired rice and soil samples from across Cambodia. Because Cd tends to be more plant available in acidic soil under less flooded conditions, (16−18) we hypothesized that rice grain Cd would be higher in rice grown during the dry season than the wet season. We further hypothesized that plant Cd would be inversely related to soil pH and CEC, as has been shown previously. (14−16,34,35) We examined paired rice and soil samples from across five provinces in Cambodia and found that plants collected in the wet season had lower Cd than those collected in the dry season, which supports our hypothesis. However, our hypothesis that grain or straw Cd would be inversely related to soil pH and CEC was not supported by our data. Instead, plant Cd was driven by soil Cd levels and potentially also by soil redox status caused by wet or dry season growth. Moreover, our data show that the health risk from Cambodian rice might be higher than previously reported.

Human Health Implications

The unpolished grain Cd levels reported here ranged from 0.002 to 1.066 mg kg^–1, which was higher than the range of 0.001 to 0.03 mg kg^–1 previously reported in a market survey by Meharg et al. (24) Because our grain was unpolished, it may have slightly higher levels compared to white rice. Previous work suggests that polishing may decrease rice grain Cd by 20–40%. (24) Even after accounting for a 40% difference between brown and white rice, the grain Cd we measured from Prey Veng and Kandal provinces grown in the dry season was still higher than that reported in the Meharg et al. (24) study, which suggests that perhaps the previous market survey did not have samples from these provinces. Our data indicates that the risk of Cd from rice in Cambodia may be higher than previously thought. According to the weekly human Cd intake thresholds of 5.8 μg kg^–1 body weight suggested by the Joint FAO/WHO Expert Committee on Food Additives (JECFA), (36) grain Cd levels of 0.12 mg kg^–1 would be the upper limit of grain Cd levels based on a 65 kg individual who consumes 450 g rice per day, 7 days per week (i.e., a typical Cambodian diet), and who does not ingest Cd from any other source. Our data show that 33% of rice samples grown in the dry season contain grain Cd above this safe limit, whereas all other samples including those collected in the wet season are below this threshold. If instead of the Cd weekly intake thresholds 0.7 μg kg^–1 body weight suggested by US Agency for Toxic Substances and Diseases Registry (ATSDR) (5) is used, then grain Cd of 0.014 mg kg^–1 would be the upper limit grain Cd levels; 89% of dry season rice and 39% of wet season rice samples exceed this limit (Figure 1).

Geographical Location

The highest soil, grain, and straw levels were obtained from Kandal and Prey Veng provinces, which were located adjacent to the Lower Mekong River southeast of Phnom Penh. This is in contrast to lower levels found in samples around the Tonle Sap. There was one rice grain sample from Prey Veng province with the Cd concentration as high as 1.066 mg kg^–1 and one straw sample also from Prey Veng with the Cd concentration as high as 1.95 mg kg^–1, while soil Cd in these sites were not excessively high. The high plant Cd in these two samples may have arisen due to atmospheric deposition of Cd-rich dust or cultivars that are efficient in plant transfer. (6,24) Ignoring the outlier, grain Cd from Kandal and Prey Veng provinces was 3 orders of magnitude higher than previously reported in a market survey. (24) The higher soil Cd from Kandal and Prey Veng provinces may be due to geogenic differences between the sampling locations that result in different soil mineral compositions; (9,37) in other areas, high soil Cd is associated with alluvial deposits. (38,39) However, higher soil Cd in these provinces could also arise from the proximity of Kandal and Prey Veng sample locations to industrial activities near Phnom Penh. (40) While identifying the source of high soil Cd is beyond the scope of the present study, additional work on source tracking could elucidate the mechanism(s) for high soil Cd from these provinces. Nevertheless, our data show that the high soil Cd led to highest grain Cd levels, which may also be due to seasonal impacts.

Seasonality

Higher grain Cd concentrations were found in samples from the dry season than those from the wet season (Figure 1, 0.118 and 0.005 mg kg^–1, respectively), and this supports our hypothesis. This finding suggests at least partial (but indirect) redox control on plant-available Cd due to likely drier soil conditions during the dry season than the wet season and limited irrigation infrastructure in the region. Drier soil conditions are well known to increase the rice Cd levels in acidic soils, (17) especially during rice heading, (41) and it is likely that dry season rice experienced drier soil conditions than wet season rice in Cambodia; (42) however, more detailed field study of soil redox potentials throughout the season would be needed to confirm this. In this work, different rice cultivars were grown across the country, which limits our ability to directly compare soil conditions in one genotype. Indeed, Cd accumulation has been shown to vary across genotypes. (43) While our data support that wet season rice has lower Cd than dry season rice, we cannot disentangle the impact of seasonality on soil Cd levels in this work.

Soil Chemical Factors

Despite the dependence of Cd plant availability on soil pH (44) and soil CEC, (14) we did not observe significant relationships between rice grain or straw Cd and soil pH or CEC (Figure 3); instead, DTPA-extractable or acid-extractable Cd in soil were stronger predictors of plant Cd levels. This finding may be because many of the samples were collected from wet season rice, and the indirect effect of redox on plant-available Cd may have been stronger than pH or CEC effects. (15) The average soil pH of 6.2 indicates slightly acidic soil conditions, and the average soil organic content (3.95%) was slightly higher than what had been previously reported. (25) Despite this, no obvious trends were observed between plant Cd and pH or CEC. Instead, we observed strong and significant positive correlations between grain (Figure 2a) and straw (Figure 2c) Cd and DTPA-extractable soil Cd, which were expected because DTPA-extractable Cd is considered representative of the plant-available soil pool and correlates with the Cd accumulated by plants. (29) We also observed strong and significant positive correlations between grain (Figure 2b) and straw (Figure 2d) Cd and acid-digestible Cd, which represents soil total Cd, (29) and this is likely because the plant-available Cd pool correlated with the total Cd pool. These data suggest that both DTPA-extractable and total soil Cd are predictors of Cd levels in grain and straw. One of the limitations of this study was that the soil redox potentials of the rice paddies during rice-growing stages were not measured and can only be inferred due to seasonality. Nevertheless, the seasonal influence on rice grain Cd content may have reflected how soil redox status affected rice Cd uptake with wetter conditions resulting in lower soil redox potential and lower plant Cd and drier conditions resulting in higher soil redox potential and higher plant Cd. (35) While we could not perform correlations separately by season due to small sample size, the data suggest that the correlations between soil Cd and plant Cd were stronger for wet season than for dry season rice, the latter of which also has higher soil Cd levels. Future work should attempt to disentangle the impacts of soil redox potential driven by wet or dry season growth and soil Cd levels in predicating Cambodian rice concentrations.

Experimental Section

Click to copy section linkSection link copied!

Sample Collection and Preparation

Paired rice (Oryza sativa L.) plant tissue and paddy soil samples were obtained from major rice-growing regions in Cambodia in March or August 2011 and previously reported for arsenic content. (26) The sampling sites were family owned small-scale rice paddies (ca. 1000 m²) located in five provinces including Kandal (KD), Prey Veng (PV), Battambang (Bat), Banteay Meanchey (Ban M), and Kampong Thom (K Thom). Samples from KD and PV were located near the Lower Mekong River and obtained at the end of the dry season in March, while the others were obtained in the wet season in August around the Tonle Sap. Note that in Cambodia at the time of sampling, limited irrigation infrastructure resulted in rice being planted when water naturally reached the fields due to the monsoon-driven swelling and shrinking of the Tonle Sap and Mekong River. Therefore, no rice crop was present in the dry season around the Tonle Sap. Sampling and processing details were reported in Seyfferth et al., 2014. (26) Briefly, rice and soil were obtained from at least three locations in each field and composited into one sample per field. Unpolished grain was separated from husk and straw and each was ground using stainless steel grinders. Soil was air-dried and sieved prior to analysis. A total of 30 rice grains, 33 straws, and 28 soil samples were analyzed here.

Rice Cd Analysis

Unpolished rice grain and straw samples were microwave-digested in concentrated trace metal grade (TMG) HNO₃ in Teflon digestion vessels (CEM Corp., Matthews, NC, USA) in a closed-vessel digestion system (MARS 6, CEM Corp.) following the established protocols. (27,28) During the digestion, the vessels were ramped to 200 °C in 20 min and held for 15 min and then allowed to cool. After digestion, the acid fraction was separated from non-dissolved Si-gel and diluted to 4% nitric acid matrix for total Cd analysis using inductively coupled plasma mass spectrometry (ICP–MS). The grain samples were analyzed on a Thermo iCap-TQ in the KED mode, whereas straw samples were analyzed with an Agilent 7500 equipped with a He collision cell. NIST1568a-certified rice, standard checks, and method blanks were included for assuring data quality. The Cd recovery of NIST1568a-certified rice was 95.3% on the Thermo iCAP-TQ and 90.7% on the Agilent 7500.

Soil Sample Analysis

The <2 mm sieved soil fractions were used for diethylenetriaminepentaacetic acid (DTPA) extraction to assess plant-available Cd. (29) For this, 10 mL of DTPA extraction solution (0.005 M DTPA, 0.1 M triethylamine, and 0.01 M CaCl₂) was added to 5 g of soil and shaken for 2 h. After centrifugation, the supernatant was passed through a 0.45 μm filter, acidified, and analyzed for Cd concentration via ICP–MS (Agilent 7500). Method blanks, duplicates, and check standards were used to ensure the data quality. The duplicates had 1.2 ± 0.3% error.

The same soil samples were also tested for acid-digestible Cd, soil pH, SOM, and CEC. For total Cd, soils were digested with concentrated TMG HNO₃ in a microwave digestion system using the EPA method 3051A, (30) where samples were ramped up to 175 °C in 5.5 min and held for 4.5 min. After centrifugation, the digest was diluted and analyzed for Cd with ICP–MS (Agilent 7500). Method blank, check standards, and NIST 2711-certified soil were used for data quality assurance. The NIST 2711-certified soil had 82% Cd recovery, likely because some of the Cd was associated with soil components that did not dissolve with HNO₃. Soil pH was measured in 1:10 (v/v) soil/water ratio, (31) SOM content was approximated by the percentage of loss of ignition (LOI), (32) and soil CEC at pH 7.0 was determined following the method by Ross (1995). (33)

Statistical Analysis

Regression analysis, multiple linear regression, and principal components analysis were performed to investigate the relations between rice Cd and Cd and soil parameters with JMP pro 15.

Author Information

Click to copy section linkSection link copied!

Corresponding Author
- Angelia L. Seyfferth - Department of Plant and Soil Sciences, University of Delaware, Newark, Delaware 19716, United States; https://orcid.org/0000-0003-3589-6815; Email: [email protected]
Author
- Ruifang Hu - Department of Plant and Soil Sciences, University of Delaware, Newark, Delaware 19716, United States
Notes
The authors declare no competing financial interest.

Acknowledgments

Click to copy section linkSection link copied!

This research was partially supported by the National Science Foundation grant nos. 1930806 and USDA NIFA 2016-67013-24846. We thank Scott Fendorf, Sarah McCurdy, Michael Schaefer, Resource Development International-Cambodia, Dina Kuy, Sokha Thorn, Lilia Barragan, Emily Rosenthal, Yadi “Simon” Wang, C. Parker Weiss, Jessica Dittmar, and Cambodian rice farming households for their contributions in obtaining the rice samples. We thank Caroline Golt, Chin Chen Kuo, and Karen Gartley for analytical assistance.

References

Click to copy section linkSection link copied!

This article references 44 other publications.

1
Nordberg, G. F. Historical Perspectives on Cadmium Toxicology. Toxicol. Appl. Pharmacol. 2009, 238, 192– 200, DOI: 10.1016/j.taap.2009.03.015
Google Scholar
1
Historical perspectives on cadmium toxicology
Nordberg, Gunnar F.
Toxicology and Applied Pharmacology (2009), 238 (3), 192-200CODEN: TXAPA9; ISSN:0041-008X. (Elsevier B.V.)
A review. The first health effects of cadmium (Cd) were reported already in 1858. Respiratory and gastrointestinal symptoms occurred among persons using Cd-contg. polishing agent. The first exptl. toxicol. studies are from 1919. Bone effects and proteinuria in humans were reported in the 1940's. After World War II, a bone disease with fractures and severe pain, the itai-itai disease, a form of Cd-induced renal osteomalacia, was identified in Japan. Subsequently, the toxicokinetics and toxicodynamics of Cd were described including its binding to the protein metallothionein. International warnings of health risks from Cd-pollution were issued in the 1970's. Reproductive and carcinogenic effects were studied at an early stage, but a quant. assessment of these effects in humans is still subject to considerable uncertainty. The World Health Organization in its International Program on Chem. Safety, WHO/IPCS (1992) (Cadmium. Environmental Health Criteria Document 134, IPCS. WHO, Geneva, 1-280.) identified renal dysfunction as the crit. effect and a crude quant. evaluation was presented. In the 1990's and 2000 several epidemiol. studies have reported adverse health effects, sometimes at low environmental exposures to Cd, in population groups in Japan, China, Europe and USA (reviewed in other contributions to the present vol.). The early identification of an important role of metallothionein in cadmium toxicol. formed the basis for recent studies using biomarkers of susceptibility to development of Cd-related renal dysfunction such as gene expression of metallothionein in peripheral lymphocytes and autoantibodies against metallothionein in blood plasma. Findings in these studies indicate that very low exposure levels to cadmium may give rise to renal dysfunction among sensitive subgroups of human populations such as persons with diabetes.
>> More from SciFinder ^®
https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXosVaqsr4%253D&md5=01db7b01cb3205c873833ad8ffc97a74
2
Järup, L.; Åkesson, A. Current Status of Cadmium as an Environmental Health Problem. Toxicol. Appl. Pharmacol. 2009, 238, 201– 208, DOI: 10.1016/j.taap.2009.04.020
Google Scholar
2
Current status of cadmium as an environmental health problem
Jarup Lars; Akesson Agneta
Toxicology and applied pharmacology (2009), 238 (3), 201-8 ISSN:.
Cadmium is a toxic metal occurring in the environment naturally and as a pollutant emanating from industrial and agricultural sources. Food is the main source of cadmium intake in the non-smoking population. The bioavailability, retention and toxicity are affected by several factors including nutritional status such as low iron status. Cadmium is efficiently retained in the kidney (half-time 10-30 years) and the concentration is proportional to that in urine (U-Cd). Cadmium is nephrotoxic, initially causing kidney tubular damage. Cadmium can also cause bone damage, either via a direct effect on bone tissue or indirectly as a result of renal dysfunction. After prolonged and/or high exposure the tubular injury may progress to glomerular damage with decreased glomerular filtration rate, and eventually to renal failure. Furthermore, recent data also suggest increased cancer risks and increased mortality in environmentally exposed populations. Dose-response assessment using a variety of early markers of kidney damage has identified U-Cd points of departure for early kidney effects between 0.5 and 3 microg Cd/g creatinine, similar to the points of departure for effects on bone. It can be anticipated that a considerable proportion of the non-smoking adult population has urinary cadmium concentrations of 0.5 microg/g creatinine or higher in non-exposed areas. For smokers this proportion is considerably higher. This implies no margin of safety between the point of departure and the exposure levels in the general population. Therefore, measures should be put in place to reduce exposure to a minimum, and the tolerably daily intake should be set in accordance with recent findings.
>> More from SciFinder ^®
https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BD1Mvns12mug%253D%253D&md5=f4c343c8dc7691a524ffa6d99a861447
3
Satarug, S.; Garrett, S. H.; Sens, M. A.; Sens, D. A. Cadmium, Environmental Exposure, and Health Outcomes. Environ. Health Perspect. 2010, 118, 182– 190, DOI: 10.1289/ehp.0901234
Google Scholar
3
Cadmium, environmental exposure, and health outcomes
Satarug, Soisungwan; Garrett, Scott H.; Sens, Mary Ann; Sens, Donald A.
Environmental Health Perspectives (2010), 118 (2), 182-190CODEN: EVHPAZ; ISSN:0091-6765. (U. S. Department of Health and Human Services, Public Health Services)
A review. Objectives: We provide an update of the issues surrounding health risk assessment of exposure to cadmium in food. Data sources: We reviewed epidemiol. studies published between 2004 and 2009 concerning the bioavailability of cadmium in food, assessment of exposure, and body burden est., along with exposure-related effects in nonoccupationally exposed populations. Data extn. and synthesis: Bioavailability of ingested cadmium has been confirmed in studies of persons with elevated dietary exposure, and the findings have been strengthened by the substantial amts. of cadmium accumulated in kidneys, eyes, and other tissues and organs of environmentally exposed individuals. We hypothesized that such accumulation results from the efficient absorption and systemic transport of cadmium, employing multiple transporters that are used for the body's acquisition of calcium, iron, zinc, and manganese. Adverse effects of cadmium on kidney and bone have been obsd. in environmentally exposed populations at frequencies higher than those predicted from models of exposure. Increasing evidence implicates cadmium in the risk of diseases that involve other tissues and organ systems at cadmium concns. that do not produce effects on bone or renal function. Conclusions: Population data raise concerns about the validity of the current safe intake level that uses the kidney as the sole target in assessing the health risk from ingested cadmium. The data also question the validity of incorporating the default 5% absorption rate in the threshold-type risk assessment model, known as the provisional tolerable weekly intake (PTWI), to derive a safe intake level for cadmium.
>> More from SciFinder ^®
https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXis1WgurY%253D&md5=b42007368f4c346f83c7c183c22c6d34
4
Nawrot, T. S.; Staessen, J. A.; Roels, H. A.; Munters, E.; Cuypers, A.; Richart, T.; Ruttens, A.; Smeets, K.; Clijsters, H.; Vangronsveld, J. Cadmium Exposure in the Population: From Health Risks to Strategies of Prevention. BioMetals 2010, 23, 769– 782, DOI: 10.1007/s10534-010-9343-z
Google Scholar
4
Cadmium exposure in the population: from health risks to strategies of prevention
Nawrot, Tim S.; Staessen, Jan A.; Roels, Harry A.; Munters, Elke; Cuypers, Ann; Richart, Tom; Ruttens, Ann; Smeets, Karen; Clijsters, Herman; Vangronsveld, Jaco
BioMetals (2010), 23 (5), 769-782CODEN: BOMEEH; ISSN:0966-0844. (Springer)
A review. We focus on the recent evidence that elucidates our understanding about the effects of cadmium (Cd) on human health and their prevention. Recently, there has been substantial progress in the exploration of the shape of the Cd concn.-response function on osteoporosis and mortality. Environmental exposure to Cd increases total mortality in a continuous fashion without evidence of a threshold, independently of kidney function and other classical factors assocd. with mortality including age, gender, smoking and social economic status. Pooled hazard rates of two recent environmental population based cohort studies revealed that for each doubling of urinary Cd concn., the relative risk for mortality increases with 17% (95% CI 4.2-33.1%; P < 0.0001). Tubular kidney damage starts at urinary Cd concns. ranging between 0.5 and 2 μg urinary Cd/g creatinine, and recent studies focusing on bone effects show increased risk of osteoporosis even at urinary Cd below 1 μg Cd/g creatinine. The non-smoking adult population has urinary Cd concns. close to or higher than 0.5 μg Cd/g creatinine. To diminish the transfer of Cd from soil to plants for human consumption, the bioavailability of soil Cd for the plants should be reduced (external bioavailability) by maintaining agricultural and garden soils pH close to neutral (pH-H2O of 7.5; pH-KCL of 6.5). Reducing the systemic bioavailability of intestinal Cd can be best achieved by preserving a balanced iron status. The latter might esp. be relevant in groups with a lower intake of iron, such as vegetarians, and women in reproductive phase of life. In exposed populations, house dust loaded with Cd is an addnl. relevant exposure route. In view of the insidious etiol. of health effects assocd. with low dose exposure to Cd and the current European Cd intake which is close to the tolerable weekly intake, one should not underestimate the importance of the recent epidemiol. evidence on Cd toxicity as to its medical and public health implications.
>> More from SciFinder ^®
https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXht1yku7nI&md5=71d2f8f57ba46e4836dbf69926e0ef7b
5
ATSDR Toxicological Profile for Cadmium; Agency for Toxic Substances and Disease Registry’s Toxicological Profiles, 2002.
Google Scholar
There is no corresponding record for this reference.
6
Clemens, S.; Aarts, M. G. M.; Thomine, S.; Verbruggen, N. Plant Science: The Key to Preventing Slow Cadmium Poisoning. Trends Plant Sci. 2013, 18, 92– 99, DOI: 10.1016/j.tplants.2012.08.003
Google Scholar
6
Plant science: the key to preventing slow cadmium poisoning
Clemens, Stephan; Aarts, Mark G. M.; Thomine, Sebastien; Verbruggen, Nathalie
Trends in Plant Science (2013), 18 (2), 92-99CODEN: TPSCF9; ISSN:1360-1385. (Elsevier Ltd.)
A review. Practically all human populations are environmentally exposed to cadmium (Cd), mostly through plant-derived food. A growing body of epidemiol. evidence suggests that there is no margin of safety between current Cd exposure levels and the threshold for adverse health effects and, hence, there is an urgent need to lower human Cd intake. Here the authors review recent studies on rice (Oryza sativa) and Cd-hyperaccumulating plants that have led to important insights into the processes controlling the passage of Cd from the soil to edible plant organs. The emerging mol. understanding of Cd uptake, root retention, root-to-shoot translocation and grain loading will enable the development of low Cd-accumulating crops.
>> More from SciFinder ^®
https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhtlGqt7%252FK&md5=0677cd542d20b9b8f1b1fef162c6ea7f
7
Reeves, P. G.; Chaney, R. L. Nutritional Status Affects the Absorption and Whole-Body and Organ Retention of Cadmium in Rats Fed Rice-Based Diets. Environ. Sci. Technol. 2002, 36, 2684– 2692, DOI: 10.1021/es0158307
Google Scholar
7
Nutritional Status Affects the Absorption and Whole-Body and Organ Retention of Cadmium in Rats Fed Rice-Based Diets
Reeves, Philip G.; Chaney, Rufus L.
Environmental Science and Technology (2002), 36 (12), 2684-2692CODEN: ESTHAG; ISSN:0013-936X. (American Chemical Society)
Staple grains such as rice, wheat, and maize consumed by different societal groups differ greatly in their concns. and bioavailability of the Cd antagonists, Zn, Fe, and Ca. Wherein, the low nutritional status of rice consumers, which results from an inadequate supply of these minerals from rice, could contribute significantly to a higher apparent susceptibility to soil Cd contamination from rice than the higher nutritional status of those who consume other grains with higher mineral content. To test this hypothesis, a 2 × 2 × 2 factorial study was conducted. Rats were fed diets with adequate or marginal amts. of dietary Zn, Fe, or Ca. The basal diets contained 40% un-enriched, milled rice fortified with 0.62 mg of Cd/kg as CdCl2 (0.25 mg of Cd/kg diet). Rat consumed the diets for 5 wk and then were fed 1 g of a similar diet contg. 109Cd-labeled rice. After 2 wk, whole-body (WB) retention of 109Cd was det. Rats then were killed, and the organs were removed for total Cd detns. Rats fed marginal concns. of dietary Zn had slightly but significantly more WB retention of 109Cd than controls; however, rats fed marginal Fe or Ca had as much as 3-fold higher retention of the label. Rats fed marginal amts. of Zn, Fe, and Ca combined retained as much as 8 times more 109Cd than rats fed adequate minerals. The effects on Cd concns. in liver and kidney were similar to the effects on 109Cd retention. These results support the hypothesis that populations exposed to dietary sources of Cd and subsisting on marginal mineral intakes could be at greater risk than well-nourished populations exposed to similar amts. of dietary Cd. Thus, different food crops can cause unequal Cd risk at equal Cd concn. if diets contg. the food are not balanced to provide adequate interacting mineral concns.
>> More from SciFinder ^®
https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38Xjs1Ggsb8%253D&md5=49c300012e86bbca555bf00bcfbb45bb
8
Kim, D.-W.; Kim, K.-Y.; Choi, B.-S.; Youn, P.; Ryu, D.-Y.; Klaassen, C. D.; Park, J.-D. Regulation of Metal Transporters by Dietary Iron, and the Relationship between Body Iron Levels and Cadmium Uptake. Arch. Toxicol. 2007, 81, 327– 334, DOI: 10.1007/s00204-006-0160-7
Google Scholar
8
Regulation of metal transporters by dietary iron, and the relationship between body iron levels and cadmium uptake
Kim, Dong-Won; Kim, Ki-Young; Choi, Byung-Sun; Youn, Pilju; Ryu, Doug-Young; Klaassen, Curtis D.; Park, Jung-Duck
Archives of Toxicology (2007), 81 (5), 327-334CODEN: ARTODN; ISSN:0340-5761. (Springer)
Fe plays essential roles in biol. processes, whereas Cd is a toxic and non-essential metal. Two metal transporters, divalent metal transporter 1 (DMT1) and metal transporter protein 1 (MTP1), are responsible for Fe transport in mammals. Here, we studied the effect of dietary Fe on the expression of these metal transporters in peripheral tissues, and the uptake by these tissues of Cd. Mice were fed an Fe-sufficient (FeS: 120 mg Fe/kg) or Fe-deficient (FeD: 2-6 mg Fe/kg) diet for 4 wk. The total Fe levels in the body were evaluated by measuring tissue Fe concns. Tissue Cd concns. were detd. 24 h after the mice received a single oral dose of Cd. Animals fed a FeD diet showed depletion of body Fe levels and accumulated 2.8-fold higher levels of Cd than the FeS group. Quant. real time RT-PCR revealed that whereas DMT1 and MTP1 were both ubiquitously expressed in all FeS peripheral tissues studied, DMT1 was highly expressed in brain, kidney, and testis, whereas MTP1 was highly expressed in liver and spleen. Depletion of the body Fe stores dramatically upregulated DMT1 and MTP1 mRNA expression in the duodenum as well as moderately upregulating their expression in several other peripheral tissues. The Fe response element pos. isoform of DMT1 was the most prominently upregulated isoform in the duodenum. Thus, DMT1 and MTP1 may play an important role in not only maintaining Fe levels but also facilitating the accumulation of Cd in the body of mammals.
>> More from SciFinder ^®
https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXkvFKis7w%253D&md5=3f1e148f11a130815b7b823bd02286d7
9
McLaughlin, M. J.; Parker, D. R.; Clarke, J. M. Metals and Micronutrients—Food Safety Issues. Field Crop. Res. 1999, 60, 143– 163, DOI: 10.1016/s0378-4290(98)00137-3
Google Scholar
There is no corresponding record for this reference.
10
Kobayashi, E.; Suwazono, Y.; Dochi, M.; Honda, R.; Kido, T. Influence of Consumption of Cadmium-Polluted Rice or Jinzu River Water on Occurrence of Renal Tubular Dysfunction and/or Itai-Itai Disease. Biol. Trace Elem. Res. 2009, 127, 257– 268, DOI: 10.1007/s12011-008-8239-z
Google Scholar
10
Influence of consumption of cadmium-polluted rice or Jinzu River water on occurrence of renal tubular dysfunction and/or Itai-itai disease
Kobayashi, Etsuko; Suwazono, Yasushi; Dochi, Mirei; Honda, Ryumon; Kido, Teruhiko
Biological Trace Element Research (2009), 127 (3), 257-268CODEN: BTERDG; ISSN:0163-4984. (Humana Press Inc.)
The aim of this study was to clarify whether consumption of cadmium (Cd)-polluted rice or Jinzu River water exerted any influence on the occurrence of renal tubular dysfunction and/or Itai-itai disease. From the participants of health examns. conducted in 1967 and 1968, 3078 subjects who had resided for >30 years in the present hamlet and were aged >50 years were selected as the target population and were divided according to their residence in 55 hamlets. In a multiple regression anal., the regression coeffs. between rice-Cd concn. and prevalence of abnormal urinary findings (proteinuria, glucosuria, or proteinuria with glucosuria) or patients with Itai-itai disease were statistically significant between both sexes. The correlation between the prevalence of users of Jinzu River water and the occurrence of glucosuria in men as well as abnormal urinary findings in women was not statistically significant. We surmise that eating Cd-polluted rice and drinking and/or cooking with Jinzu River water influenced the occurrence of Itai-itai disease. The occurrence of renal tubular dysfunction is likely to have also been influenced by both factors, with eating Cd-polluted rice having a greater impact on the occurrence of renal tubular dysfunction as compared to drinking and/or cooking with Jinzu River water.
>> More from SciFinder ^®
https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtlKrtr8%253D&md5=9b00add827de4de5a970e3f437b29f6b
11
Buchauer, M. J. Contamination of Soil and Vegetation near a Zinc Smelter by Zinc, Cadmium, Copper, and Lead. Environ. Sci. Technol. 1973, 7, 131– 135, DOI: 10.1021/es60074a004
Google Scholar
11
Contamination of soil and vegetation near a zinc smelter by zinc, cadmium, copper, and lead
Buchauer, Marilyn J.
Environmental Science and Technology (1973), 7 (2), 131-5CODEN: ESTHAG; ISSN:0013-936X.
Metal oxide fumes escaping from 2 zinc smelters in Palmerton, Pa., have highly contaminated soil and vegetation with Zn, Cd, Cu, and Pb. Within 1 km of the smelters, 135,000 ppm Zn, 1750 ppm Cd, 2000 ppm Cu, and 2000 ppm Pb were measured in the O2 horizon. Approx. 90% of metals deposited on the soil surface were retained in the top 15 cm of the soil profile. Depauperate trees within 2 km of the smelters contained up to 4500 ppm Zn and 70 ppm Cd by weight in washed, oven-dried foliage. Metal aerosols may enter the leaves directly, presumably through open stomates.
>> More from SciFinder ^®
https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaE3sXnsFGiuw%253D%253D&md5=63348a9ff7414a4517b59038043bc218
12
Morrow, H. Cadmium and Cadmium Alloys. Kirk-Othmer Encyclopedia of Chemical Technology; Wiley, 2010.
Google Scholar
There is no corresponding record for this reference.
13
Grant, C. A.; Sheppard, S. C. Fertilizer Impacts on Cadmium Availability in Agricultural Soils and Crops. Hum. Ecol. Risk Assess. 2008, 14, 210– 228, DOI: 10.1080/10807030801934895
Google Scholar
13
Fertilizer Impacts on Cadmium Availability in Agricultural Soils and Crops
Grant, C. A.; Sheppard, S. C.
Human and Ecological Risk Assessment (2008), 14 (2), 210-228CODEN: HERAFR; ISSN:1080-7039. (Taylor & Francis, Inc.)
A review. Ingestion in food is a major pathway of cadmium (Cd) exposure for humans. It is therefore desirable to ensure that Cd concns. in crops that enter the human food chain do not increase to levels that may lead to health risks. Phosphorus fertilizers contain Cd as a contaminant at levels varying from trace amts. to as much as 300 mg Cd kg-1 of dry product and therefore can be a major source of Cd input to agricultural systems. Fertilization can influence Cd accumulation in crops by direct Cd addn. and by indirect effects on soil pH, ionic strength, Zn concn., rhizosphere chem., microbial activity, and plant growth. Cadmium will accumulate in the soils from fertilizer applications if the amt. of Cd added in fertilizer is greater than the amt. of Cd removal, whether in harvested crop removal or other loss pathways such as leaching, erosion, or bioturbation. Assessment of the impact of fertilizer management practices on the risk of Cd toxicity to the soil ecosystem and the risk of movement of Cd into the human diet must consider both the direct influence of Cd addn. as a fertilizer contaminant and the indirect effects of fertilizer application on Cd phytoavailability. Cadmium accumulation in soils and crops can be minimized by adoption of management practices that improve fertilizer-use efficiency while minimizing Cd input.
>> More from SciFinder ^®
https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXks1eit70%253D&md5=291cd2ddb870dcca12122bb6a298bd15
14
Haghiri, F. Plant Uptake of Cadmium as Influenced by Cation Exchange Capacity, Organic Matter, Zinc, and Soil Temperature. J. Environ. Qual. 1974, 3, 180– 183, DOI: 10.2134/jeq1974.00472425000300020021x
Google Scholar
14
Plant uptake of cadmium as influenced by cation exchange capacity, organic matter, zinc, and soil temperature
Haghiri, F.
Journal of Environmental Quality (1974), 3 (2), 180-3CODEN: JEVQAA; ISSN:0047-2425.
In expts. with soils high in clay, addn. of org. matter (muck) increased the cation exchange capacity (CEC) of the soil. With increased CEC, shoots of oats (Avena sativa) or of soybeans (Glycine max) took up less Cd when CdCl2 was added to the soil. The Cd-retaining power of the soil was mainly related to its CEC, not to chelating ability. The Cd uptake of soybean shoots increased with increasing soil temp. With 10 ppm soil-applied Cd, addn. of 5-50 ppm Zn (as Zn(NO3)2) increased both the Cd and Zn contents of soybean shoots. The increased Cd content resulted mainly from decreased plant growth. However, at ≥100 ppm Zn, soybean shoots took up less Cd. The suppression of Cd uptake with relatively large concns. of Zn was not a practical procedure since high Zn levels drastically diminished plant growth. Annual applications of sewage sludge may not result in undue uptake of Cd present in the sewage but soil levels of Cd will increase. Crop damage by Cd may eventually result if addn. of org. matter is discontinued.
>> More from SciFinder ^®
https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaE2cXktFagurs%253D&md5=7510b852311c1c5d48e5cfd66df8e249
15
Kikuchi, T.; Okazaki, M.; Kimura, S. D.; Motobayashi, T.; Baasansuren, J.; Hattori, T.; Abe, T. Suppressive Effects of Magnesium Oxide Materials on Cadmium Uptake and Accumulation into Rice Grains. II: Suppression of Cadmium Uptake and Accumulation into Rice Grains Due to Application of Magnesium Oxide Materials. J. Hazard. Mater. 2008, 154, 294– 299, DOI: 10.1016/j.jhazmat.2007.10.025
Google Scholar
15
Suppressive effects of magnesium oxide materials on cadmium uptake and accumulation into rice grains II: Suppression of cadmium uptake and accumulation into rice grains due to application of magnesium oxide materials.
Kikuchi, Tetsuro; Okazaki, Masanori; Kimura, Sonoko Dorothea; Motobayashi, Takashi; Baasansuren, Jamsranjav; Hattori, Takayuki; Abe, Toshio
Journal of Hazardous Materials (2008), 154 (1-3), 294-299CODEN: JHMAD9; ISSN:0304-3894. (Elsevier B.V.)
The objective is to assess the applicability of a com. MgO and a composite material contg. MgO and natural minerals (MgO-SH-A) as the soil amendments for suppression of Cd uptake and accumulation into rice grains. A cultivation expt. of rice plants (Oryza sativa L. cv. Kinuhikari) was conducted in an actual Cd-contaminated alluvial paddy field to evaluate the effectiveness of these materials. The plant available fractions of Cd in the paddy soil significantly decreased by application of com. MgO at 2250 Kg/ha or MgO-SH-A at 4500 Kg/ha. These decreases would be primarily attributed to the increase in soil pH due to applications of the MgO materials because these soil Cd fractions were significantly neg. correlated with the soil pH. Even under a suppressive condition for Cd uptake by rice plants, i.e., continuous flooding of the paddy field around the heading stage, applications of these materials further reduced Cd concn. in brown rice as compared to that from the control. It was concluded that the 2 MgO materials examd. would be effective in preventing Cd contamination of rice grains grown in Cd-polluted paddy fields.
>> More from SciFinder ^®
https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXlsFCjs7o%253D&md5=8c779fe9588ca73b1f466c785da13c4c
16
Xian, X.; Shokohifard, G. I. Effect of PH on Chemical Forms and Plant Availability of Cadmium, Zinc, and Lead in Polluted Soils. Water, Air, Soil Pollut. 1989, 45, 265– 273, DOI: 10.1007/bf00283457
Google Scholar
16
Effect of pH on chemical forms and plant availability of cadmium, zinc, and lead in polluted soils
Xian, Xingfu; Gholamhoss in Shokohifard
Water, Air, and Soil Pollution (1989), 45 (3-4), 265-73CODEN: WAPLAC; ISSN:0049-6979.
The effect of pH on chem. forms and plant availability of heavy metals in 3 polluted soils was investigated. The soils were adjusted to pH values of 7.0, 6.0, and 4.5, then sequentially extd. so that Cd, Zn, and Pb could be partitioned into 5 operationally defined chem. fractions: exchangeable, carbonate, Fe-Mn oxide, org., and residual. Kidney beans were grown in the soils to investigate plant availability of the metals in relation to changes of their levels in chem. forms resulting from alteration of soil pH. Alteration of pH resulted in changes of chem. forms of the metals in the soils, and at lower pH the changes were more significant. When soil pH values were decreased from 7.0 to 4.55, levels of Cd, Zn, and Pb in exchangeable form increased, decreased in carbonates and decreased slightly in Fe-Mn oxide forms. Their levels in org. and residual forms were unchanged. Although concn. of metals in plants increased with redn. in soil pH values, dry matter yields were also restricted, so that the amt. of metal uptake were almost similar. The uptake rate of the metals in the exchangeable + carbonate forms was the same for the 3 elements in all the cases.
>> More from SciFinder ^®
https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3cXitVertw%253D%253D&md5=6b1426cdbd5ad29af9e20c50f0567674
17
Arao, T.; Kawasaki, A.; Baba, K.; Mori, S.; Matsumoto, S. Effects of Water Management on Cadmium and Arsenic Accumulation and Dimethylarsinic Acid Concentrations in Japanese Rice. Environ. Sci. Technol. 2009, 43, 9361– 9367, DOI: 10.1021/es9022738
Google Scholar
17
Effects of Water Management on Cadmium and Arsenic Accumulation and Dimethylarsinic Acid Concentrations in Japanese Rice
Arao, Tomohito; Kawasaki, Akira; Baba, Koji; Mori, Shinsuke; Matsumoto, Shingo
Environmental Science & Technology (2009), 43 (24), 9361-9367CODEN: ESTHAG; ISSN:0013-936X. (American Chemical Society)
Rice consumption is a major source of cadmium and arsenic for the population of Asia. We investigated the effects of water management in rice paddy on levels of cadmium and arsenic in Japanese rice grains. Flooding increased arsenic concns. in rice grains, whereas aerobic treatment increased the concn. of cadmium. Flooding for 3 wk before and after heading was most effective in reducing grain cadmium concns., but this treatment increased the arsenic concn. considerably, whereas aerobic treatment during the same period was effective in reducing arsenic concns. but increased the cadmium concn. markedly. Flooding treatment after heading was found to be more effective than flooding treatment before heading in reducing rice grain cadmium without a concomitant increase in total arsenic levels, although it increased inorg. arsenic levels. Concns. of dimethylarsinic acid (DMA) in grain were very low under aerobic conditions but increased under flooded conditions. DMA accounted for 3-52% of the total arsenic concn. in grain grown in soil with a lower arsenic concn. and 10-80% in soil with a higher arsenic concn. A possible explanation for the accumulation of DMA in rice grains is that DMA translocates from shoots/roots to the grains more readily than does inorg. arsenic.
>> More from SciFinder ^®
https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtl2qu7rI&md5=895f3bba46d6ed3369a3c9b1375cc917
18
de Livera, J.; McLaughlin, M. J.; Hettiarachchi, G. M.; Kirby, J. K.; Beak, D. G. Cadmium Solubility in Paddy Soils: Effects of Soil Oxidation, Metal Sulfides and Competitive Ions. Sci. Total Environ. 2011, 409, 1489– 1497, DOI: 10.1016/j.scitotenv.2010.12.028
Google Scholar
18
Cadmium solubility in paddy soils: Effects of soil oxidation, metal sulfides and competitive ions
de Livera, Jennifer; McLaughlin, Mike J.; Hettiarachchi, Ganga M.; Kirby, Jason K.; Beak, Douglas G.
Science of the Total Environment (2011), 409 (8), 1489-1497CODEN: STENDL; ISSN:0048-9697. (Elsevier B.V.)
Cadmium (Cd) is a nonessential element for human nutrition and is an agricultural soil contaminant. Cadmium soly. in paddy soils affects Cd accumulation in the grain of rice. This is a human health risk, exacerbated by the fact that rice grains are deficient in iron (Fe) and zinc (Zn) for human nutrition. To find ways of limiting this potential risk, we investigated factors influencing Cd soly. relative to Fe and Zn during preharvest drainage of paddy soils, in which soil oxidn. is accompanied by the grain-filling stage of rice growth. This was simulated in temp.-controlled "reaction cell" expts. by first excluding oxygen to incubate soil suspensions anaerobically, then inducing aerobic conditions. In treatments without sulfur addn., the ratios of Cd:Fe and Cd:Zn in soln. increased during the aerobic phase while Cd concns. were unaffected and the Fe and Zn concns. decreased. However, in treatments with added sulfur (as sulfate), up to 34 % of sulfur (S) was pptd. as sulfide minerals during the anaerobic phase and the Cd:Fe and Cd:Zn ratios in soln. during the aerobic phase were lower than for treatments without S addn. When S was added, Cd soly. decreased whereas Fe and Zn were unaffected. When soil was spiked with Zn the Cd:Zn ratio was lower in soln. during the aerobic phase, due to higher Zn concns. Decreased Cd:Fe and Cd:Zn ratios during the grain filling stage could potentially limit Cd enrichment in paddy rice grain due to competitive ion effects for root uptake.
>> More from SciFinder ^®
https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXisFWrs7s%253D&md5=ca555c5f9cdaa914396dba8d846cbf28
19
Williams, P. N.; Lei, M.; Sun, G.; Huang, Q.; Lu, Y.; Deacon, C.; Meharg, A. A.; Zhu, Y.-G. Occurrence and Partitioning of Cadmium, Arsenic and Lead in Mine Impacted Paddy Rice: Hunan, China. Environ. Sci. Technol. 2009, 43, 637– 642, DOI: 10.1021/es802412r
Google Scholar
19
Occurrence and Partitioning of Cadmium, Arsenic and Lead in Mine Impacted Paddy Rice: Hunan, China
Williams, Paul N.; Lei, Ming; Sun, Guoxin; Huang, Qing; Lu, Ying; Deacon, Claire; Meharg, Andrew A.; Zhu, Yong-Guan
Environmental Science & Technology (2009), 43 (3), 637-642CODEN: ESTHAG; ISSN:0013-936X. (American Chemical Society)
Paddy rice has been likened to nictiana sp in its ability to scavenge cadmium (Cd) from soil, whereas arsenic (As) accumulation is commonly an order of magnitude higher than in other cereal crops. In areas such as those found in parts of Hunan province in south central China, base-metal mining activities and rice farming coexist. Therefore there is a considerable likelihood that lead (Pb), in addn. to Cd and As, will accumulate in rice grown in parts of this region above levels suitable for human consumption. To test this hypothesis, a widespread provincial survey of rice from mine spoilt paddies (n = 100), in addn. to a follow-up market grain survey (n = 122) conducted in mine impacted areas was undertaken to det. the safety of local rice supply networks. Furthermore, a specific Cd, As, and Pb biogeochem. survey of paddy soil and rice was conducted within southern China, targeting sites impacted by mining of varying intensities to calibrate rice metal(loid) transfer models and transfer factors that can be used to predict tissue loading. Results revealed a no. of highly significant correlations between shoot, husk, bran, and endosperm rice tissue fractions and that rice from mining areas was enriched in Cd, As, and Pb. Sixty-five, 50, and 34% of all the mine-impacted field rice was predicted to fail national food stds. for Cd, As, and Pb, resp. Although, not as elevated as the grains from the mine-impacted field survey, it was demonstrated that metal(loid) tainted rice was entering food supply chains intended for direct human consumption.
>> More from SciFinder ^®
https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhvFKhtw%253D%253D&md5=70c9e3db703b92d0c1a6c1ab5963d476
20
Zhuang, P.; Zou, B.; Li, N. Y.; Li, Z. A. Heavy Metal Contamination in Soils and Food Crops around Dabaoshan Mine in Guangdong, China: Implication for Human Health. Environ. Geochem. Health 2009, 31, 707– 715, DOI: 10.1007/s10653-009-9248-3
Google Scholar
20
Heavy metal contamination in soils and food crops around Dabaoshan mine in Guangdong, China: implication for human health
Zhuang, P.; Zou, B.; Li, N. Y.; Li, Z. A.
Environmental Geochemistry and Health (2009), 31 (6), 707-715CODEN: EGHEE3; ISSN:0269-4042. (Springer)
This study was designed to investigate heavy metal (Cu, Zn, Pb, and Cd) contamination levels of soils, vegetables, and rice grown in the vicinity of the Dabaoshan mine, south China. The concn. of Cu, Zn, Pb, and Cd in paddy soil exceeded the max. allowable concns. for Chinese agricultural soil. The heavy metal concns. (mg kg-1, dry wt. basis) in vegetables ranged from 5.0 to 14.3 for Cu, 34.7 to 170 for Zn, 0.90 to 2.23 for Pb, and 0.45 to 4.1 for Cd. The concns. of Pb and Cd in rice grain exceeded the max. permissible limits in China. Dietary intake of Pb and Cd through the consumption of rice and certain vegetable exceeded the recommended dietary allowance levels. The status of heavy metal concns. of food crops grown in the vicinity of Dabaoshan mine and their implications for human health should be further investigated.
>> More from SciFinder ^®
https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhsVers7vJ&md5=921e35c9d95475c092c5865656552873
21
Yang, Q. W.; Lan, C. Y.; Wang, H. B.; Zhuang, P.; Shu, W. S. Cadmium in Soil-Rice System and Health Risk Associated with the Use of Untreated Mining Wastewater for Irrigation in Lechang, China. Agric. Water Manag. 2006, 84, 147– 152, DOI: 10.1016/j.agwat.2006.01.005
Google Scholar
There is no corresponding record for this reference.
22
Honma, T.; Ohba, H.; Kaneko, A.; Nakamura, K.; Makino, T.; Katou, H. Effects of Soil Amendments on Arsenic and Cadmium Uptake by Rice Plants (Oryza Sativa L. Cv. Koshihikari) under Different Water Management Practices. Soil Sci. Plant Nutr. 2016, 62, 349– 356, DOI: 10.1080/00380768.2016.1196569
Google Scholar
22
Effects of soil amendments on arsenic and cadmium uptake by rice plants (Oryza sativa L. cv. Koshihikari) under different water management practices
Honma, Toshimitsu; Ohba, Hirotomo; Kaneko, Ayako; Nakamura, Ken; Makino, Tomoyuki; Katou, Hidetaka
Soil Science and Plant Nutrition (Abingdon, United Kingdom) (2016), 62 (4), 349-356CODEN: SSPNAW; ISSN:0038-0768. (Taylor & Francis Ltd.)
Concns. of arsenic (As) and cadmium (Cd) in rice grains are of public concern for human health. We conducted field expts. to investigate the effects of soil amendment applications, combined with different water management practices, on As and Cd uptake by rice plants (Oryza sativa L. cv. Koshihikari). Prolonged flooding, practiced for pre-heading 3 wk and post-heading 3 wk, led to elevated As concns. in the soil soln. and rice grain. Rainfed water management, in which no irrigation was practiced after midseason drainage until harvest, led to elevated Cd concns. in the soil soln. and rice grain. Application of short-range-order iron hydroxide (IO) reduced As uptake by rice plants, whereas Cd uptake was reduced by the application of converter furnace slag (CFS). However, it was difficult to simultaneously reduce the As and Cd uptake by a single countermeasure of the water management practice or the soil amendment application. Prolonged flooding combined with the application of IO, or rainfed water management with the application of CFS, were promising measures for the simultaneous redn. of As and Cd uptake by rice plants.
>> More from SciFinder ^®
https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhtF2hsrjP&md5=7fef3cc4ceb63f8f6f2cc050f2aeed51
23
Hu, P.; Li, Z.; Yuan, C.; Ouyang, Y.; Zhou, L.; Huang, J.; Huang, Y.; Luo, Y.; Christie, P.; Wu, L. Effect of Water Management on Cadmium and Arsenic Accumulation by Rice (Oryza Sativa L.) with Different Metal Accumulation Capacities. J. Soils Sediments 2013, 13, 916– 924, DOI: 10.1007/s11368-013-0658-6
Google Scholar
23
Effect of water management on cadmium and arsenic accumulation by rice (Oryza sativa L.) with different metal accumulation capacities
Hu, Pengjie; Li, Zhu; Yuan, Cheng; Ouyang, Younan; Zhou, Liqiang; Huang, Jiexue; Huang, Yujuan; Luo, Yongming; Christie, Peter; Wu, Longhua
Journal of Soils and Sediments (2013), 13 (5), 916-924CODEN: JSSOAJ; ISSN:1439-0108. (Springer)
Purpose Water management affects the bioavailability of cadmium (Cd) and arsenic (As) in the soil and hence their accumulation in rice grains and grain yields. However, Cd and As show opposite responses to soil water content, but information, particularly on irrigation, is missing on a field scale. The purpose of the present study was therefore to find a water management regime that can lower accumulation of both Cd and As in grain without yield loss. Materials and methods Two rice (Oryza sativa L.) cultivars, A16 and A159, with different grain Cd accumulation capacities were employed in field plot expts. with four water management regimes comprising aerobic, intermittent, conventional practice and flooded. The dynamics of Cd and As bioavailability in the soil and Cd and As concns. in roots, straw and grains were detd. at the early tillering, full tillering, panicle initiation, filling and maturity stages of crop growth. Results and discussion The lower water content regimes (aerobic and intermittent) mostly led to higher soil HCl-extractable Cd than the higher soil water content regimes (conventional and flooded). HCl-extractable As in contrast was favored by the higher soil water content treatments. Conventional and flooded irrigation accordingly gave higher plant As concns. but lower Cd compared to aerobic and intermittent irrigation. Cd concns. in roots and straw of both varieties increased with growth stage, esp. in aerobic and intermittent regimes, while As concns. in plants showed little change or a slight decrease. As the water irrigation vol. increased from aerobic to flooded, brown rice Cd decreased from 1.15 to 0.02 mg kg-1 in cultivar A16 and from 1.60 to 0.05 mg kg-1 in cultivar A159, whereas brown rice As increased. Aerobic and flooded treatments produced approx. 10-20 % lower grain yields than intermittent and conventional treatments. Cultivars with low Cd accumulation capacity show higher brown rice grain As than those with high Cd uptake capacity. Conclusions Of the four water management regimes, the conventional irrigation method (flooding maintained until full tillering followed by intermittent irrigation) ensured high yield with low Cd and As in the brown rice and so remains the recommended irrigation regime.
>> More from SciFinder ^®
https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXlvVCjsbc%253D&md5=24a83a388fc31b1b72caf0440b22167f
24
Meharg, A. A.; Norton, G.; Deacon, C.; Williams, P.; Adomako, E. E.; Price, A.; Zhu, Y.; Li, G.; Zhao, F.-J.; McGrath, S.; Villada, A.; Sommella, A.; De Silva, P. M. C. S.; Brammer, H.; Dasgupta, T.; Islam, M. R. Variation in Rice Cadmium Related to Human Exposure. Environ. Sci. Technol. 2013, 47, 5613– 5618, DOI: 10.1021/es400521h
Google Scholar
24
Variation in Rice Cadmium Related to Human Exposure
Meharg, Andrew A.; Norton, Gareth; Deacon, Claire; Williams, Paul; Adomako, Eureka E.; Price, Adam; Zhu, Yongguan; Li, Gang; Zhao, Fang-Jie; McGrath, Steve; Villada, Antia; Sommella, Alessia; De Silva, P. Mangala C. S.; Brammer, Hugh; Dasgupta, Tapash; Islam, M. Rafiqul
Environmental Science & Technology (2013), 47 (11), 5613-5618CODEN: ESTHAG; ISSN:0013-936X. (American Chemical Society)
Cereal grains are the dominant source of cadmium in the human diet, with rice being to the fore. Here we explore the effect of geog., genetic, and processing (milling) factors on rice grain cadmium and rice consumption rates that lead to dietary variance in cadmium intake. From a survey of 12 countries on four continents, cadmium levels in rice grain were the highest in Bangladesh and Sri Lanka, with both these countries also having high per capita rice intakes. For Bangladesh and Sri Lanka, there was high weekly intake of cadmium from rice, leading to intakes deemed unsafe by international and national regulators. While genetic variance, and to a lesser extent milling, provide strategies for reducing cadmium in rice, caution has to be used, as there is environmental regulation as well as genetic regulation of cadmium accumulation within rice grains. For countries that import rice, grain cadmium can be controlled by where that rice is sourced, but for countries with subsistence rice economies that have high levels of cadmium in rice grain, agronomic and breeding strategies are required to lower grain cadmium.
>> More from SciFinder ^®
https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXnsFShu70%253D&md5=6e5ced97dcf54428ebfb416c589ab6d9
25
Nesbitt, H.; Chan, P.. Rice-Based Farming Systems ; 1997.
Google Scholar
There is no corresponding record for this reference.
26
Seyfferth, A. L.; McCurdy, S.; Schaefer, M. V.; Fendorf, S. Arsenic Concentrations in Paddy Soil and Rice and Health Implications for Major Rice-Growing Regions of Cambodia. Environ. Sci. Technol. 2014, 48, 4699– 4706, DOI: 10.1021/es405016t
Google Scholar
26
Arsenic Concentrations in Paddy Soil and Rice and Health Implications for Major Rice-Growing Regions of Cambodia
Seyfferth, Angelia L.; McCurdy, Sarah; Schaefer, Michael V.; Fendorf, Scott
Environmental Science & Technology (2014), 48 (9), 4699-4706CODEN: ESTHAG; ISSN:0013-936X. (American Chemical Society)
Despite the global importance of As in rice, research has primarily focused on Bangladesh, India, China, and the United States with limited attention given to other countries. Owing to both indigenous As within the soil and the possible increases arising from the onset of irrigation with groundwater, an assessment of As in rice within Cambodia is needed, which offers a "base-case" comparison against sediments of similar origin that comprise rice paddy soils where As-contaminated water is used for irrigation (e.g., Bangladesh). Here, we evaluated the As content of rice from five provinces (Kandal, Prey Veng, Battambang, Banteay Meanchey, and Kampong Thom) in the rice-growing regions of Cambodia and coupled that data to soil-chem. factors based on extns. of paddy soil collected and processed under anoxic conditions. At total soil As concns. ranging 0.8 to 18 μg g-1, total grain As concns. averaged 0.2 μg g-1 and ranged from 0.1 to 0.37 with Banteay Meanchey rice having significantly higher values than Prey Veng rice. Overall, soil-extractable concns. of As, Fe, P, and Si and total As were poor predictors of grain As concns. While biogeochem. factors leading to redn. of As(V)-bearing Fe(III) oxides are likely most important for predicting plant-available As, husk and straw As concns. were the most significant predictors of grain-As levels among our measured parameters.
>> More from SciFinder ^®
https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXlslSmur4%253D&md5=540059c8c5e5d56f6b9ad550c7a8a54f
27
Seyfferth, A. L.; Morris, A. H.; Gill, R.; Kearns, K. A.; Mann, J. N.; Paukett, M.; Leskanic, C. Soil Incorporation of Silica-Rich Rice Husk Decreases Inorganic Arsenic in Rice Grain. J. Agric. Food Chem. 2016, 64, 3760– 3766, DOI: 10.1021/acs.jafc.6b01201
Google Scholar
27
Soil Incorporation of Silica-Rich Rice Husk Decreases Inorganic Arsenic in Rice Grain
Seyfferth, Angelia L.; Morris, Andrew H.; Gill, Rattandeep; Kearns, Kelli A.; Mann, Jessica N.; Paukett, Michelle; Leskanic, Corey
Journal of Agricultural and Food Chemistry (2016), 64 (19), 3760-3766CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)
Arsenic decreases rice yield, and inorg. grain As threatens human health; thus, strategies to decrease rice As are critically needed. Increased plant-available silica (Si) can decrease rice As, yet the source of Si matters. Rice husk, an underutilized and Si-rich byproduct of rice prodn. that contains less labile C and an order of magnitude less As than rice straw, may be an economically viable Si resource to decrease rice As, yet the impact of rice husk incorporation on As in the rice-soil nexus has not been reported. This proof-of-concept study shows that rice husk incorporation to soil (1% wt./wt.) decreases inorg. grain As by 25-50% without neg. affecting grain Cd, yield, or dissolved CH4 levels. Rice husk is a crit. yet perhaps overlooked resource to improve soil quality through enhanced nutrient availability and attenuate human health risks through consumption of As-laden grain.
>> More from SciFinder ^®
https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XmsFOntbw%253D&md5=df754ff33edaa92861b978d0f50b612c
28
Teasley, W. A.; Limmer, M. A.; Seyfferth, A. L. How Rice (Oryza Sativa L.) Responds to Elevated As under Different Si-Rich Soil Amendments. Environ Sci Technol. 2017, 51, 10335– 10343, DOI: 10.1021/acs.est.7b01740
Google Scholar
28
How Rice (Oryza sativa L.) Responds to Elevated As under Different Si-Rich Soil Amendments
Teasley, William A.; Limmer, Matthew A.; Seyfferth, Angelia L.
Environmental Science & Technology (2017), 51 (18), 10335-10343CODEN: ESTHAG; ISSN:0013-936X. (American Chemical Society)
Several strategies exist to mitigate As impacts on rice and each has its set of tradeoffs with respect to yield, inorg. As content in grain, and CH4 emissions. The addn. of Si to paddy soil can decrease As uptake by rice but how rice will respond to elevated As when soil is amended with Si-rich materials is unresolved. Here, we evaluated yield impacts and grain As content and speciation in rice exposed to elevated As in response to different Si-rich soil amendments including rice husk, rice husk ash, and CaSiO3 in a pot study. We found that As-induced yield losses were alleviated by Husk amendment, partially alleviated by Ash amendment, and not affected by CaSiO3 amendment. Furthermore, Husk was the only tested Si-amendment to significantly decrease grain As concns. Husk amendment was likely effective at decreasing grain As and improving yield because it provided more plant-available Si, particularly during the reproductive and ripening phases. Both Husk and Ash provided K, which also played a role in yield improvement. This study demonstrates that while Si-rich amendments can affect rice uptake of As, the kinetics of Si dissoln. and nutrient availability can also affect As uptake and toxicity in rice.
>> More from SciFinder ^®
https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtlShtb3J&md5=b897c6844fb21ef41b9a7113127e0ecd
29
Sparks, D. L. Methods of Soil Analysis: Chemical Methods; Soil Science Society of America Book Series Number 5; Wiley, 1996, pp 754– 755.
Google Scholar
There is no corresponding record for this reference.
30
EPA Method 3051A Microwave Assisted Acid Digestion of Sediments, Sludges, Soils, and Oils. EPA Method, 2007, Vol. 3(September), pp 1– 8.
Google Scholar
There is no corresponding record for this reference.
31
Eckert, D.; Sims, J. T. Recommended Soil PH and Lime Requirement Tests. Analysis 1995, 2006, 19– 26
Google Scholar
There is no corresponding record for this reference.
32
Schulte, E. E.; Hoskins, B. Recommended Soil Organic Matter Tests Recommended soil testing procedures for the Northeastern united States, 1995, pp 63– 74.
Google Scholar
There is no corresponding record for this reference.
33
Ross, D. S.; Ketterings, Q. Recommended Soil Tests for Determining Soil Cation Exchange CapacityNortheast (Recommended Soil testing Procedures for the Northeastern United States). Agricultural Experiment Station University: Delaware, Newark, 1995; Vol. 62–69.
Google Scholar
There is no corresponding record for this reference.
34
Yu, H.-Y.; Liu, C.; Zhu, J.; Li, F.; Deng, D.-M.; Wang, Q.; Liu, C. Cadmium Availability in Rice Paddy Fields from a Mining Area: The Effects of Soil Properties Highlighting Iron Fractions and PH Value. Environ. Pollut. 2016, 209, 38– 45, DOI: 10.1016/j.envpol.2015.11.021
Google Scholar
34
Cadmium availability in rice paddy fields from a mining area: The effects of soil properties highlighting iron fractions and pH value
Yu, Huan-Yun; Liu, Chuanping; Zhu, Jishu; Li, Fangbai; Deng, Dong-Mei; Wang, Qi; Liu, Chengshuai
Environmental Pollution (Oxford, United Kingdom) (2016), 209 (), 38-45CODEN: ENPOEK; ISSN:0269-7491. (Elsevier Ltd.)
Cadmium (Cd) availability can be significantly affected by soil properties. The effect of pH value on Cd availability has been confirmed. Paddy soils in South China generally contain high contents of iron (Fe). Thus, it is hypothesized that Fe fractions, in addn. to pH value, may play an important role in the Cd bioavailability in paddy soil and this requires further investigation. In this study, 73 paired soil and rice plant samples were collected from paddy fields those were contaminated by acid mine drainage contg. Cd. The contents of Fe in the amorphous and DCB-extractable Fe oxides were significantly and neg. correlated with the Cd content in rice grain or straw (excluding DCB-extractable Fe vs Cd in straw). In addn., the concn. of HCl-extractable Fe(II) derived from Fe(III) redn. was pos. correlated with the Cd content in rice grain or straw. These results suggest that soil Fe redox could affect the availability of Cd in rice plant. Contribution assessment of soil properties to Cd accumulation in rice grain based on random forest (RF) and stochastic gradient boosting (SGB) showed that pH value should be the most important factor and the content of Fe in the amorphous Fe oxides should be the second most important factor in affecting Cd content in rice grain. Overall, compared with the studies from temperate regions, such as Europe and northern China, Fe oxide exhibited its unique role in the bioavailability of Cd in the reddish paddy soil from our study area. The exploration of practical remediation strategies for Cd from the perspective of Fe oxide may be promising.
>> More from SciFinder ^®
https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhvFansrfP&md5=229d8fc149318376f19045c6bec03b1e
35
Yuan, C.; Li, F.; Cao, W.; Yang, Z.; Hu, M.; Sun, W. Cadmium Solubility in Paddy Soil Amended with Organic Matter, Sulfate, and Iron Oxide in Alternative Watering Conditions. J. Hazard. Mater. 2019, 378, 120672, DOI: 10.1016/j.jhazmat.2019.05.065
Google Scholar
35
Cadmium solubility in paddy soil amended with organic matter, sulfate, and iron oxide in alternative watering conditions
Yuan, Chaolei; Li, Fangbai; Cao, Wenhua; Yang, Zi; Hu, Min; Sun, Weimin
Journal of Hazardous Materials (2019), 378 (), 120672CODEN: JHMAD9; ISSN:0304-3894. (Elsevier B.V.)
We successfully accounted for the dynamics of cadmium (Cd) soly. in paddy soil that contained a realistically low total Cd concn. (0.36 mg kg-1) after submergence and redrying by monitoring multiple chem. and microbial soil properties. The addn. of rice straw promoted greater microbial iron redn. and induced a greater increase in soil pH after submergence, compared to the control and treatments with added gypsum or hematite. Consequently, dissolved Cd decreased to under the detection limit in one week in the straw-amended treatment but remained high even after eight weeks in the other three treatments. The Cd soly. strongly correlated with soil pH and was unlikely to decrease due to Cd pptn. in secondary iron minerals. After five weeks of redrying, the dissolved Cd content was still the lowest, and the putative iron-reducing bacteria Geobacter remained the most abundant in the straw-amended soil. The results suggest that the addn. of org. matter can efficiently immobilize soil Cd at an environmentally realistic concn. by stimulating the microbial redn. of native oxidized soil components after submergence, while adding extra iron oxide or sulfate alone is not effective because it does not eliminate the limitation imposed by electron donors on microbial redn.
>> More from SciFinder ^®
https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhtFOjsL%252FP&md5=ff88fbf8693e7248ae0e4d1e71214649
36
World Health Organization Evaluation of Certain Food Additives and Contaminants; World Health Organization technical report series; World Health Organization, 2013.
Google Scholar
There is no corresponding record for this reference.
37
Sparks, D. L. Environmental Soil Chemistry; Academic Press, 2003.
Google Scholar
There is no corresponding record for this reference.
38
Bradley, S. B.; Cox, J. J. Heavy Metals in the Hamps and Manifold Valleys, North Staffordshire, U.K.: Distribution in Floodplain Soils. Sci. Total Environ. 1986, 50, 103– 128, DOI: 10.1016/0048-9697(86)90354-2
Google Scholar
38
Heavy metals in the Hamps and Manifold valleys, North Staffordshire, U.K.; distribution in floodplain soils
Bradley, S. B.; Cox, J. J.
Science of the Total Environment (1986), 50 (), 103-28CODEN: STENDL; ISSN:0048-9697.
Historic mining for base metals in the catchment of the River Hamps and of the River Manifold in North Staffordshire has left a legacy of floodplain soils which are contaminated with heavy metals. The principal mines in the catchments yielded large quantities of Cu ore, esp. between 1760 and 1790, and some floodplain soils contain >2000 mg Cu/kg; they also contain elevated concns. of Pb, Zn, and Cd. Background concns. of these metals, as detd. by statistical anal., are (kg-1): 52 mg Pb; 145 mg Zn; 17 mg Cu; and 0.40 mg Cd in the whole soil and 200 mg Pb; 251 mg Zn; 182 mg Cu; and 6.76 mg Cd in the fraction <63 μm. Although the mines are sepd. by only 5 km there is a significant difference in the Pb/Cu ratio between the 2 catchments, probably due to a variation across the mineralization. Metal levels in the floodplain soils decrease away from the mine in the order Pb > Cd > Zn > Cu in the Manifold, and Pb > Cu > Cd > Zn in the Hamps. Reprocessing of spoil heaps on the Manifold affected the spectrum of particle sizes supplied to the river, and sediments are finer than those on the Hamps. Also, the extn. of metals during reprocessing has resulted in the sand fraction being depleted. This contrast between an enhanced supply of fine sediments in the Manifold and predominantly coarse in the Hamps is manifest in the floodplain landforms deposited during the mining era. Fine sediments have accumulated by vertical accretion in the Manifold, while coarse sediments were deposited by lateral accretion as gravel splays on the Hamps, i.e. sheets of coarse sediment on the floodplain.
>> More from SciFinder ^®
https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL28XksVWkuro%253D&md5=db7652fefa44532e9c43301d8fed8688
39
Holmgren, G. G. S.; Meyer, M. W.; Chaney, R. L.; Daniels, R. B. Cadmium, Lead, Zinc, Copper, and Nickel in Agricultural Soils of the United States of America. J. Environ. Qual. 1993, 22, 335– 348, DOI: 10.2134/jeq1993.00472425002200020015x
Google Scholar
39
Cadmium, lead, zinc, copper, and nickel in agricultural soils of the United States of America
Holmgren, G. G. S.; Meyer, M. W.; Chaney, R. L.; Daniels, R. B.
Journal of Environmental Quality (1993), 22 (2), 335-48CODEN: JEVQAA; ISSN:0047-2425.
Surface soil samples from 307 different soil series were analyzed for Pb, Cd, Zn, Cu, Ni, cation exchange capacity (CEC), org. C, and pH in the course of a study of trace element uptake by major agricultural crops. The soil data are summarized statistically and in map form to show their interactions and generalized geog. distribution patterns. Amts. of all five metal elements are generally low in the Southeast. A regional high of about 15 mg/kg Pb covers the Mississippi, Ohio, and Missouri River valleys. Higher values for other elements are generally concd. in the West and in the lower Mississippi River Valley. Max. Cd levels were found in soils of the coast ranges of central and southern California. Copper levels are noticeably higher in org. soil areas of Florida, Oregon, and the Great Lakes. Nickel and Cu concns. are high in serpentine soil areas of California. Nickel levels are also somewhat higher in the glaciated areas of the northern great plains and in northern Maine. For the entire dataset, the values of the min.-max., 5th, 50th, and 95th percentiles are as follows: (mg/kg dry soil) Cd, <0.005 to 2.0, 0.036, 0.20, 0.78; Pb, 0.5 to 135, 4.0, 11, 23; Zn 1.5 to 264, 8.0, 53, 126; Cu 0.3 to 495, 3.8, 18.5, 95; Ni, 0.7 to 269, 4.1, 18.2, 57; pH (pH units) 3.9-8.9, 4.7, 6.1, 8.1; CEC (cmol/kg) 0.6 to 204, 2.4, 14.0, 135; and org. C % 0.09 to 63, 0.36, 1.05, 33.3. Metal levels generally increased with increasing clay concn.
>> More from SciFinder ^®
https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2cXns1yn&md5=882e7e596ef37f6b9fafa94c503a0ab8
40
San, V.; Spoann, V.; Schmidt, J. Industrial Pollution Load Assessment in Phnom Penh, Cambodia Using an Industrial Pollution Projection System. Sci. Total Environ. 2018, 615, 990– 999, DOI: 10.1016/j.scitotenv.2017.10.006
Google Scholar
40
Industrial pollution load assessment in Phnom Penh, Cambodia, using an industrial pollution projection system
San, Vibol; Spoann, Vin; Schmidt, Johannes
Science of the Total Environment (2018), 615 (), 990-999CODEN: STENDL; ISSN:0048-9697. (Elsevier B.V.)
Approx. 56% out of the total 1302 Cambodian firms are operated in the Capital city of Cambodia. The necessary information on industrial pollution to set strategies, priorities and action plans on environmental protection issues is absent in Cambodia. In the absence of this data, effective environmental protection cannot be implemented. The objective is to est. industrial pollution load using the Industrial Pollution Projection System, a rapid environmental management tool for assessment of pollution load, to produce a scientific rational basis for prepg. future policy direction to reduce industrial pollution in Phnom Penh city. Factory data between 1994 and 2014 obtained from the Ministry of Industry and Handicraft of Cambodia were used in our study. Due to the high no. of employees, the total environmental load generated in Phnom Penh city was estd. to be 476,981 Mg in 2014. Phnom Penh city generated 189,109 Mg VOC, 165,411 Mg of toxic chems. to air, 38,523 Mg of toxic chems. to land, and 28,968 Mg SO2 in 2014. The results of the estn. show that the Textiles and Apparel sector was the highest generators of toxic chems. into land and air, and toxic metals into land, air and water, while the Basic Metal sector was the greatest contributor of toxic chems. to water. The Textiles and Apparel sector alone emitted 436,016 Mg of total pollution load. The results indicate that the Dangkao and Meanchey districts were the greatest emitters of all pollutants in Phnom Penh. The results suggest that redn. in industrial pollution could be achieved by focusing on the most polluting sectors and areas. Adopting waste minimization strategies, which include cleaner prodn. processes, will not only reduce the cost of controlling pollution, it will also make manufg. more efficient thereby increasing profits while reducing pollution load in the long run.
>> More from SciFinder ^®
https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhs1elsrzP&md5=f26d02506ca5a0dca852c2758d9dfa3f
41
Inahara, M.; Ogawa, Y.; Azuma, H. Countermeasure by Means of Flooding in Latter Growth Stage to Restrain Cadmium Uptake by Lowland Rice [Oryza Sativa]. AGRIS 2007, 78, 149– 155, DOI: 10.20710/dojo.78.2_149
Google Scholar
There is no corresponding record for this reference.
42
Gerson, H.; Shneider, D.; Dabek, P.; Dominguez, M.; Raftopoulos, A.; Zhang, B.; Bostick, B. Interns Find Links Between Climate and Arsenic Levels in Rice. 2020.https://news.climate.columbia.edu/2020/09/02/climate-arsenic-levels-rice/ (accessed on January 21, 2021).
Google Scholar
There is no corresponding record for this reference.
43
Arao, T.; Ae, N. Genotypic Variations in Cadmium Levels of Rice Grain. Soil Sci. Plant Nutr. 2003, 49, 473– 479, DOI: 10.1080/00380768.2003.10410035
Google Scholar
43
Genotypic variations in cadmium levels of rice grain
Arao, T.; Ae, N.
Soil Science and Plant Nutrition (Tokyo, Japan) (2003), 49 (4), 473-479CODEN: SSPNAW; ISSN:0038-0768. (Japanese Society of Soil Science and Plant Nutrition)
To identify rice grain genotypes with a lower cadmium content, 49 cultivars of rice were tested under upland conditions, using two types of soils contaminated with cadmium (A: alluvial and B: volcanic ash soil) in 1999 and 2000. Results of ranking of grain cadmium concns. were similar between these 2 yr. NIPPONBARE, KOSHIHIKARI, and HU-LO-TAO belonged to the rice grain group with the lowest cadmium contents. KASALATH could be categorized as a variety with a medium cadmium content, hereafter referred to as "medium cadmium variety," and MILYANG23 and PEH-KUH-TSAO-TU as varieties with high cadmium contents, hereafter referred to as "high cadmium varieties.". These five varieties except for HU-LO-TAO from the above six typical varieties were grown in submerged pots (paddy conditions), and the ranking of the grain cadmium content was almost the same as that in the upland condition pots. These results imply that it may be possible to select paddy rice varieties with a low cadmium content even when growth occurred under upland conditions. The possibility of screening for lower cadmium content in rice grain in soln. culture was examd. The shoot cadmium concns. in soln. culture were not significantly lower in NIPPONBARE and KOSHIHIKARI than those of MILYANG23 and PEH-KUH-TSAO-TU after 4 d of cadmium addn. Only PEH-KUH-TSAO-TU showed a higher shoot cadmium concn. than the other varieties after 27 d of cadmium addn. Thus, as a preliminary evaluation, a screening method using soln. culture would not be suitable for detecting genotypes with a low cadmium content in grain within 1 mo after cadmium addn. These results suggest that the status of available cadmium in soil differs from that of available cadmium in soln. culture. Cadmium distribution for grain (i.e., grain cadmium content ratio to total uptake in the terrestrial part of plants) was evaluated among these 5 varieties. KASALATH absorbed a relatively high amt. of cadmium, although cadmium distribution to grain in KASALATH was the lowest among the 5 varieties. On the other hand, in MILYANG23, a much higher amt. of cadmium was translocated to the grain than in the other 4 varieties, suggesting the existence of genetic variability in cadmium translocation from shoots to grains.
>> More from SciFinder ^®
https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXnsVSmtbk%253D&md5=ecedadea881ef576786f5d7e567ea279
44
Zhao, F.-J.; Wang, P. Arsenic and Cadmium Accumulation in Rice and Mitigation Strategies. Plant Soil 2020, 446, 1– 21, DOI: 10.1007/s11104-019-04374-6
Google Scholar
44
Arsenic and cadmium accumulation in rice and mitigation strategies
Zhao, Fang-Jie; Wang, Peng
Plant and Soil (2020), 446 (1-2), 1-21CODEN: PLSOA2; ISSN:0032-079X. (Springer)
A review. Background: Arsenic (As) and cadmium (Cd) are two toxic elements that have a relatively high risk of transfer from paddy soil to rice grain. Rice is a major dietary source of these two elements for populations consuming rice as a staple food. Reducing their accumulation in rice grain is important for food safety and human health. Scope: We review recent progress in understanding the biogeochem. processes controlling As and Cd bioavailability in paddy soil, the mechanisms of their uptake, translocation and detoxification in rice plants, and strategies to reduce their accumulation in rice grain. Similarities and differences between the two elements are emphasized. Some knowledge gaps are also identified. Conclusions: The concns. of As and Cd in rice grain vary by three orders of magnitude, depending on the bioavailability of the two elements in soil, rice genotype and growing conditions. The redox potential in paddy soil has a profound but opposite effect on As and Cd bioavailability, whereas soil pH affects Cd bioavailability more than As bioavailability. A no. of key genes involved in As and Cd uptake, translocation, sequestration, and detoxification in rice have been characterized. Allelic variations of several genes underlying the variations in Cd accumulation have been identified, but more remains to be elucidated, esp. for As. Two types of strategies can be used to reduce As and Cd accumulation, reducing their bioavailability in soil or their uptake and translocation in rice. Reducing the accumulation of both As and Cd in rice simultaneously remains a great challenge.
>> More from SciFinder ^®
https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXit1Gqt7vN&md5=608a963326f389dac819019028c61a0c

Cited By

Click to copy section linkSection link copied!

This article is cited by 3 publications.

Ruifang Hu, Jennifer A. Cooper, Samira H. Daroub, Carolin F. Kerl, Britta Planer-Friedrich, Angelia L. Seyfferth. Low levels of arsenic and cadmium in rice grown in southern Florida Histosols - Impacts of water management and soil thickness. Science of The Total Environment 2023, 869 , 161712. https://doi.org/10.1016/j.scitotenv.2023.161712
Ruoyu Wang, Panting Sang, Yahui Guo, Ping Jin, Yuliang Cheng, Hang Yu, Yunfei Xie, Weirong Yao, He Qian. Cadmium in food: Source, distribution and removal. Food Chemistry 2023, 405 , 134666. https://doi.org/10.1016/j.foodchem.2022.134666
Thomas Murphy, Kongkea Phan, Kim Neil Irvine, David Lean. The Role of Micronutrients and Toxic Metals in the Management of Epidemics in Cambodia. International Journal of Environmental Research and Public Health 2021, 18 (21) , 11446. https://doi.org/10.3390/ijerph182111446

Download PDF

Open PDF

Get e-Alerts

ACS Omega

Cite this: ACS Omega 2021, 6, 30, 19876–19882

Click to copy citationCitation copied!

https://doi.org/10.1021/acsomega.1c02741

Published July 23, 2021

CC-BY-NC-ND 4.0 .

Article Views

Altmetric

Citations

Learn about these metrics

Article Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.

Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.

The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated.

Abstract
High Resolution Image
Download MS PowerPoint Slide
Figure 1
Figure 1. Rice grain Cd concentrations by province and season. Blue and gray broken lines represent the rice Cd limit for a 65 kg adult who consumes 450 g rice per day by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) (5.8 μg kg^–1 body weight per week) or US Agency for Toxic Substances and Diseases Registry (ATSDR) (0.7 μg kg^–1 body weight per week), respectively.
High Resolution Image
Download MS PowerPoint Slide
Figure 2
Figure 2. Relationships between the logarithms of grain Cd and soil DTPA-extractable Cd (a) or soil acid digestible Cd (b), and straw Cd and soil DTPA-extractable Cd (c) or soil acid digestible Cd (d). Note that the samples collected during the wet season are shown in blue and those collected during the dry season are shown in orange.
High Resolution Image
Download MS PowerPoint Slide
Figure 3
Figure 3. Relationships between grain Cd and soil pH (a) or soil CEC (b), straw Cd and soil pH (c), or soil CEC (d). None of these correlations were statistically significant. Note that the samples collected during the wet season are shown in blue and those collected during the dry season are shown in orange.
High Resolution Image
Download MS PowerPoint Slide
References
This article references 44 other publications.
1. 1
  Nordberg, G. F. Historical Perspectives on Cadmium Toxicology. Toxicol. Appl. Pharmacol. 2009, 238, 192– 200, DOI: 10.1016/j.taap.2009.03.015
  1
  Historical perspectives on cadmium toxicology
  Nordberg, Gunnar F.
  Toxicology and Applied Pharmacology (2009), 238 (3), 192-200CODEN: TXAPA9; ISSN:0041-008X. (Elsevier B.V.)
  A review. The first health effects of cadmium (Cd) were reported already in 1858. Respiratory and gastrointestinal symptoms occurred among persons using Cd-contg. polishing agent. The first exptl. toxicol. studies are from 1919. Bone effects and proteinuria in humans were reported in the 1940's. After World War II, a bone disease with fractures and severe pain, the itai-itai disease, a form of Cd-induced renal osteomalacia, was identified in Japan. Subsequently, the toxicokinetics and toxicodynamics of Cd were described including its binding to the protein metallothionein. International warnings of health risks from Cd-pollution were issued in the 1970's. Reproductive and carcinogenic effects were studied at an early stage, but a quant. assessment of these effects in humans is still subject to considerable uncertainty. The World Health Organization in its International Program on Chem. Safety, WHO/IPCS (1992) (Cadmium. Environmental Health Criteria Document 134, IPCS. WHO, Geneva, 1-280.) identified renal dysfunction as the crit. effect and a crude quant. evaluation was presented. In the 1990's and 2000 several epidemiol. studies have reported adverse health effects, sometimes at low environmental exposures to Cd, in population groups in Japan, China, Europe and USA (reviewed in other contributions to the present vol.). The early identification of an important role of metallothionein in cadmium toxicol. formed the basis for recent studies using biomarkers of susceptibility to development of Cd-related renal dysfunction such as gene expression of metallothionein in peripheral lymphocytes and autoantibodies against metallothionein in blood plasma. Findings in these studies indicate that very low exposure levels to cadmium may give rise to renal dysfunction among sensitive subgroups of human populations such as persons with diabetes.
  >> More from SciFinder ^®
  https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXosVaqsr4%253D&md5=01db7b01cb3205c873833ad8ffc97a74
2. 2
  Järup, L.; Åkesson, A. Current Status of Cadmium as an Environmental Health Problem. Toxicol. Appl. Pharmacol. 2009, 238, 201– 208, DOI: 10.1016/j.taap.2009.04.020
  2
  Current status of cadmium as an environmental health problem
  Jarup Lars; Akesson Agneta
  Toxicology and applied pharmacology (2009), 238 (3), 201-8 ISSN:.
  Cadmium is a toxic metal occurring in the environment naturally and as a pollutant emanating from industrial and agricultural sources. Food is the main source of cadmium intake in the non-smoking population. The bioavailability, retention and toxicity are affected by several factors including nutritional status such as low iron status. Cadmium is efficiently retained in the kidney (half-time 10-30 years) and the concentration is proportional to that in urine (U-Cd). Cadmium is nephrotoxic, initially causing kidney tubular damage. Cadmium can also cause bone damage, either via a direct effect on bone tissue or indirectly as a result of renal dysfunction. After prolonged and/or high exposure the tubular injury may progress to glomerular damage with decreased glomerular filtration rate, and eventually to renal failure. Furthermore, recent data also suggest increased cancer risks and increased mortality in environmentally exposed populations. Dose-response assessment using a variety of early markers of kidney damage has identified U-Cd points of departure for early kidney effects between 0.5 and 3 microg Cd/g creatinine, similar to the points of departure for effects on bone. It can be anticipated that a considerable proportion of the non-smoking adult population has urinary cadmium concentrations of 0.5 microg/g creatinine or higher in non-exposed areas. For smokers this proportion is considerably higher. This implies no margin of safety between the point of departure and the exposure levels in the general population. Therefore, measures should be put in place to reduce exposure to a minimum, and the tolerably daily intake should be set in accordance with recent findings.
  >> More from SciFinder ^®
  https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BD1Mvns12mug%253D%253D&md5=f4c343c8dc7691a524ffa6d99a861447
3. 3
  Satarug, S.; Garrett, S. H.; Sens, M. A.; Sens, D. A. Cadmium, Environmental Exposure, and Health Outcomes. Environ. Health Perspect. 2010, 118, 182– 190, DOI: 10.1289/ehp.0901234
  3
  Cadmium, environmental exposure, and health outcomes
  Satarug, Soisungwan; Garrett, Scott H.; Sens, Mary Ann; Sens, Donald A.
  Environmental Health Perspectives (2010), 118 (2), 182-190CODEN: EVHPAZ; ISSN:0091-6765. (U. S. Department of Health and Human Services, Public Health Services)
  A review. Objectives: We provide an update of the issues surrounding health risk assessment of exposure to cadmium in food. Data sources: We reviewed epidemiol. studies published between 2004 and 2009 concerning the bioavailability of cadmium in food, assessment of exposure, and body burden est., along with exposure-related effects in nonoccupationally exposed populations. Data extn. and synthesis: Bioavailability of ingested cadmium has been confirmed in studies of persons with elevated dietary exposure, and the findings have been strengthened by the substantial amts. of cadmium accumulated in kidneys, eyes, and other tissues and organs of environmentally exposed individuals. We hypothesized that such accumulation results from the efficient absorption and systemic transport of cadmium, employing multiple transporters that are used for the body's acquisition of calcium, iron, zinc, and manganese. Adverse effects of cadmium on kidney and bone have been obsd. in environmentally exposed populations at frequencies higher than those predicted from models of exposure. Increasing evidence implicates cadmium in the risk of diseases that involve other tissues and organ systems at cadmium concns. that do not produce effects on bone or renal function. Conclusions: Population data raise concerns about the validity of the current safe intake level that uses the kidney as the sole target in assessing the health risk from ingested cadmium. The data also question the validity of incorporating the default 5% absorption rate in the threshold-type risk assessment model, known as the provisional tolerable weekly intake (PTWI), to derive a safe intake level for cadmium.
  >> More from SciFinder ^®
  https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXis1WgurY%253D&md5=b42007368f4c346f83c7c183c22c6d34
4. 4
  Nawrot, T. S.; Staessen, J. A.; Roels, H. A.; Munters, E.; Cuypers, A.; Richart, T.; Ruttens, A.; Smeets, K.; Clijsters, H.; Vangronsveld, J. Cadmium Exposure in the Population: From Health Risks to Strategies of Prevention. BioMetals 2010, 23, 769– 782, DOI: 10.1007/s10534-010-9343-z
  4
  Cadmium exposure in the population: from health risks to strategies of prevention
  Nawrot, Tim S.; Staessen, Jan A.; Roels, Harry A.; Munters, Elke; Cuypers, Ann; Richart, Tom; Ruttens, Ann; Smeets, Karen; Clijsters, Herman; Vangronsveld, Jaco
  BioMetals (2010), 23 (5), 769-782CODEN: BOMEEH; ISSN:0966-0844. (Springer)
  A review. We focus on the recent evidence that elucidates our understanding about the effects of cadmium (Cd) on human health and their prevention. Recently, there has been substantial progress in the exploration of the shape of the Cd concn.-response function on osteoporosis and mortality. Environmental exposure to Cd increases total mortality in a continuous fashion without evidence of a threshold, independently of kidney function and other classical factors assocd. with mortality including age, gender, smoking and social economic status. Pooled hazard rates of two recent environmental population based cohort studies revealed that for each doubling of urinary Cd concn., the relative risk for mortality increases with 17% (95% CI 4.2-33.1%; P < 0.0001). Tubular kidney damage starts at urinary Cd concns. ranging between 0.5 and 2 μg urinary Cd/g creatinine, and recent studies focusing on bone effects show increased risk of osteoporosis even at urinary Cd below 1 μg Cd/g creatinine. The non-smoking adult population has urinary Cd concns. close to or higher than 0.5 μg Cd/g creatinine. To diminish the transfer of Cd from soil to plants for human consumption, the bioavailability of soil Cd for the plants should be reduced (external bioavailability) by maintaining agricultural and garden soils pH close to neutral (pH-H2O of 7.5; pH-KCL of 6.5). Reducing the systemic bioavailability of intestinal Cd can be best achieved by preserving a balanced iron status. The latter might esp. be relevant in groups with a lower intake of iron, such as vegetarians, and women in reproductive phase of life. In exposed populations, house dust loaded with Cd is an addnl. relevant exposure route. In view of the insidious etiol. of health effects assocd. with low dose exposure to Cd and the current European Cd intake which is close to the tolerable weekly intake, one should not underestimate the importance of the recent epidemiol. evidence on Cd toxicity as to its medical and public health implications.
  >> More from SciFinder ^®
  https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXht1yku7nI&md5=71d2f8f57ba46e4836dbf69926e0ef7b
5. 5
  ATSDR Toxicological Profile for Cadmium; Agency for Toxic Substances and Disease Registry’s Toxicological Profiles, 2002.
  There is no corresponding record for this reference.
6. 6
  Clemens, S.; Aarts, M. G. M.; Thomine, S.; Verbruggen, N. Plant Science: The Key to Preventing Slow Cadmium Poisoning. Trends Plant Sci. 2013, 18, 92– 99, DOI: 10.1016/j.tplants.2012.08.003
  6
  Plant science: the key to preventing slow cadmium poisoning
  Clemens, Stephan; Aarts, Mark G. M.; Thomine, Sebastien; Verbruggen, Nathalie
  Trends in Plant Science (2013), 18 (2), 92-99CODEN: TPSCF9; ISSN:1360-1385. (Elsevier Ltd.)
  A review. Practically all human populations are environmentally exposed to cadmium (Cd), mostly through plant-derived food. A growing body of epidemiol. evidence suggests that there is no margin of safety between current Cd exposure levels and the threshold for adverse health effects and, hence, there is an urgent need to lower human Cd intake. Here the authors review recent studies on rice (Oryza sativa) and Cd-hyperaccumulating plants that have led to important insights into the processes controlling the passage of Cd from the soil to edible plant organs. The emerging mol. understanding of Cd uptake, root retention, root-to-shoot translocation and grain loading will enable the development of low Cd-accumulating crops.
  >> More from SciFinder ^®
  https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhtlGqt7%252FK&md5=0677cd542d20b9b8f1b1fef162c6ea7f
7. 7
  Reeves, P. G.; Chaney, R. L. Nutritional Status Affects the Absorption and Whole-Body and Organ Retention of Cadmium in Rats Fed Rice-Based Diets. Environ. Sci. Technol. 2002, 36, 2684– 2692, DOI: 10.1021/es0158307
  7
  Nutritional Status Affects the Absorption and Whole-Body and Organ Retention of Cadmium in Rats Fed Rice-Based Diets
  Reeves, Philip G.; Chaney, Rufus L.
  Environmental Science and Technology (2002), 36 (12), 2684-2692CODEN: ESTHAG; ISSN:0013-936X. (American Chemical Society)
  Staple grains such as rice, wheat, and maize consumed by different societal groups differ greatly in their concns. and bioavailability of the Cd antagonists, Zn, Fe, and Ca. Wherein, the low nutritional status of rice consumers, which results from an inadequate supply of these minerals from rice, could contribute significantly to a higher apparent susceptibility to soil Cd contamination from rice than the higher nutritional status of those who consume other grains with higher mineral content. To test this hypothesis, a 2 × 2 × 2 factorial study was conducted. Rats were fed diets with adequate or marginal amts. of dietary Zn, Fe, or Ca. The basal diets contained 40% un-enriched, milled rice fortified with 0.62 mg of Cd/kg as CdCl2 (0.25 mg of Cd/kg diet). Rat consumed the diets for 5 wk and then were fed 1 g of a similar diet contg. 109Cd-labeled rice. After 2 wk, whole-body (WB) retention of 109Cd was det. Rats then were killed, and the organs were removed for total Cd detns. Rats fed marginal concns. of dietary Zn had slightly but significantly more WB retention of 109Cd than controls; however, rats fed marginal Fe or Ca had as much as 3-fold higher retention of the label. Rats fed marginal amts. of Zn, Fe, and Ca combined retained as much as 8 times more 109Cd than rats fed adequate minerals. The effects on Cd concns. in liver and kidney were similar to the effects on 109Cd retention. These results support the hypothesis that populations exposed to dietary sources of Cd and subsisting on marginal mineral intakes could be at greater risk than well-nourished populations exposed to similar amts. of dietary Cd. Thus, different food crops can cause unequal Cd risk at equal Cd concn. if diets contg. the food are not balanced to provide adequate interacting mineral concns.
  >> More from SciFinder ^®
  https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38Xjs1Ggsb8%253D&md5=49c300012e86bbca555bf00bcfbb45bb
8. 8
  Kim, D.-W.; Kim, K.-Y.; Choi, B.-S.; Youn, P.; Ryu, D.-Y.; Klaassen, C. D.; Park, J.-D. Regulation of Metal Transporters by Dietary Iron, and the Relationship between Body Iron Levels and Cadmium Uptake. Arch. Toxicol. 2007, 81, 327– 334, DOI: 10.1007/s00204-006-0160-7
  8
  Regulation of metal transporters by dietary iron, and the relationship between body iron levels and cadmium uptake
  Kim, Dong-Won; Kim, Ki-Young; Choi, Byung-Sun; Youn, Pilju; Ryu, Doug-Young; Klaassen, Curtis D.; Park, Jung-Duck
  Archives of Toxicology (2007), 81 (5), 327-334CODEN: ARTODN; ISSN:0340-5761. (Springer)
  Fe plays essential roles in biol. processes, whereas Cd is a toxic and non-essential metal. Two metal transporters, divalent metal transporter 1 (DMT1) and metal transporter protein 1 (MTP1), are responsible for Fe transport in mammals. Here, we studied the effect of dietary Fe on the expression of these metal transporters in peripheral tissues, and the uptake by these tissues of Cd. Mice were fed an Fe-sufficient (FeS: 120 mg Fe/kg) or Fe-deficient (FeD: 2-6 mg Fe/kg) diet for 4 wk. The total Fe levels in the body were evaluated by measuring tissue Fe concns. Tissue Cd concns. were detd. 24 h after the mice received a single oral dose of Cd. Animals fed a FeD diet showed depletion of body Fe levels and accumulated 2.8-fold higher levels of Cd than the FeS group. Quant. real time RT-PCR revealed that whereas DMT1 and MTP1 were both ubiquitously expressed in all FeS peripheral tissues studied, DMT1 was highly expressed in brain, kidney, and testis, whereas MTP1 was highly expressed in liver and spleen. Depletion of the body Fe stores dramatically upregulated DMT1 and MTP1 mRNA expression in the duodenum as well as moderately upregulating their expression in several other peripheral tissues. The Fe response element pos. isoform of DMT1 was the most prominently upregulated isoform in the duodenum. Thus, DMT1 and MTP1 may play an important role in not only maintaining Fe levels but also facilitating the accumulation of Cd in the body of mammals.
  >> More from SciFinder ^®
  https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXkvFKis7w%253D&md5=3f1e148f11a130815b7b823bd02286d7
9. 9
  McLaughlin, M. J.; Parker, D. R.; Clarke, J. M. Metals and Micronutrients—Food Safety Issues. Field Crop. Res. 1999, 60, 143– 163, DOI: 10.1016/s0378-4290(98)00137-3
  There is no corresponding record for this reference.
10. 10
  Kobayashi, E.; Suwazono, Y.; Dochi, M.; Honda, R.; Kido, T. Influence of Consumption of Cadmium-Polluted Rice or Jinzu River Water on Occurrence of Renal Tubular Dysfunction and/or Itai-Itai Disease. Biol. Trace Elem. Res. 2009, 127, 257– 268, DOI: 10.1007/s12011-008-8239-z
  10
  Influence of consumption of cadmium-polluted rice or Jinzu River water on occurrence of renal tubular dysfunction and/or Itai-itai disease
  Kobayashi, Etsuko; Suwazono, Yasushi; Dochi, Mirei; Honda, Ryumon; Kido, Teruhiko
  Biological Trace Element Research (2009), 127 (3), 257-268CODEN: BTERDG; ISSN:0163-4984. (Humana Press Inc.)
  The aim of this study was to clarify whether consumption of cadmium (Cd)-polluted rice or Jinzu River water exerted any influence on the occurrence of renal tubular dysfunction and/or Itai-itai disease. From the participants of health examns. conducted in 1967 and 1968, 3078 subjects who had resided for >30 years in the present hamlet and were aged >50 years were selected as the target population and were divided according to their residence in 55 hamlets. In a multiple regression anal., the regression coeffs. between rice-Cd concn. and prevalence of abnormal urinary findings (proteinuria, glucosuria, or proteinuria with glucosuria) or patients with Itai-itai disease were statistically significant between both sexes. The correlation between the prevalence of users of Jinzu River water and the occurrence of glucosuria in men as well as abnormal urinary findings in women was not statistically significant. We surmise that eating Cd-polluted rice and drinking and/or cooking with Jinzu River water influenced the occurrence of Itai-itai disease. The occurrence of renal tubular dysfunction is likely to have also been influenced by both factors, with eating Cd-polluted rice having a greater impact on the occurrence of renal tubular dysfunction as compared to drinking and/or cooking with Jinzu River water.
  >> More from SciFinder ^®
  https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtlKrtr8%253D&md5=9b00add827de4de5a970e3f437b29f6b
11. 11
  Buchauer, M. J. Contamination of Soil and Vegetation near a Zinc Smelter by Zinc, Cadmium, Copper, and Lead. Environ. Sci. Technol. 1973, 7, 131– 135, DOI: 10.1021/es60074a004
  11
  Contamination of soil and vegetation near a zinc smelter by zinc, cadmium, copper, and lead
  Buchauer, Marilyn J.
  Environmental Science and Technology (1973), 7 (2), 131-5CODEN: ESTHAG; ISSN:0013-936X.
  Metal oxide fumes escaping from 2 zinc smelters in Palmerton, Pa., have highly contaminated soil and vegetation with Zn, Cd, Cu, and Pb. Within 1 km of the smelters, 135,000 ppm Zn, 1750 ppm Cd, 2000 ppm Cu, and 2000 ppm Pb were measured in the O2 horizon. Approx. 90% of metals deposited on the soil surface were retained in the top 15 cm of the soil profile. Depauperate trees within 2 km of the smelters contained up to 4500 ppm Zn and 70 ppm Cd by weight in washed, oven-dried foliage. Metal aerosols may enter the leaves directly, presumably through open stomates.
  >> More from SciFinder ^®
  https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaE3sXnsFGiuw%253D%253D&md5=63348a9ff7414a4517b59038043bc218
12. 12
  Morrow, H. Cadmium and Cadmium Alloys. Kirk-Othmer Encyclopedia of Chemical Technology; Wiley, 2010.
  There is no corresponding record for this reference.
13. 13
  Grant, C. A.; Sheppard, S. C. Fertilizer Impacts on Cadmium Availability in Agricultural Soils and Crops. Hum. Ecol. Risk Assess. 2008, 14, 210– 228, DOI: 10.1080/10807030801934895
  13
  Fertilizer Impacts on Cadmium Availability in Agricultural Soils and Crops
  Grant, C. A.; Sheppard, S. C.
  Human and Ecological Risk Assessment (2008), 14 (2), 210-228CODEN: HERAFR; ISSN:1080-7039. (Taylor & Francis, Inc.)
  A review. Ingestion in food is a major pathway of cadmium (Cd) exposure for humans. It is therefore desirable to ensure that Cd concns. in crops that enter the human food chain do not increase to levels that may lead to health risks. Phosphorus fertilizers contain Cd as a contaminant at levels varying from trace amts. to as much as 300 mg Cd kg-1 of dry product and therefore can be a major source of Cd input to agricultural systems. Fertilization can influence Cd accumulation in crops by direct Cd addn. and by indirect effects on soil pH, ionic strength, Zn concn., rhizosphere chem., microbial activity, and plant growth. Cadmium will accumulate in the soils from fertilizer applications if the amt. of Cd added in fertilizer is greater than the amt. of Cd removal, whether in harvested crop removal or other loss pathways such as leaching, erosion, or bioturbation. Assessment of the impact of fertilizer management practices on the risk of Cd toxicity to the soil ecosystem and the risk of movement of Cd into the human diet must consider both the direct influence of Cd addn. as a fertilizer contaminant and the indirect effects of fertilizer application on Cd phytoavailability. Cadmium accumulation in soils and crops can be minimized by adoption of management practices that improve fertilizer-use efficiency while minimizing Cd input.
  >> More from SciFinder ^®
  https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXks1eit70%253D&md5=291cd2ddb870dcca12122bb6a298bd15
14. 14
  Haghiri, F. Plant Uptake of Cadmium as Influenced by Cation Exchange Capacity, Organic Matter, Zinc, and Soil Temperature. J. Environ. Qual. 1974, 3, 180– 183, DOI: 10.2134/jeq1974.00472425000300020021x
  14
  Plant uptake of cadmium as influenced by cation exchange capacity, organic matter, zinc, and soil temperature
  Haghiri, F.
  Journal of Environmental Quality (1974), 3 (2), 180-3CODEN: JEVQAA; ISSN:0047-2425.
  In expts. with soils high in clay, addn. of org. matter (muck) increased the cation exchange capacity (CEC) of the soil. With increased CEC, shoots of oats (Avena sativa) or of soybeans (Glycine max) took up less Cd when CdCl2 was added to the soil. The Cd-retaining power of the soil was mainly related to its CEC, not to chelating ability. The Cd uptake of soybean shoots increased with increasing soil temp. With 10 ppm soil-applied Cd, addn. of 5-50 ppm Zn (as Zn(NO3)2) increased both the Cd and Zn contents of soybean shoots. The increased Cd content resulted mainly from decreased plant growth. However, at ≥100 ppm Zn, soybean shoots took up less Cd. The suppression of Cd uptake with relatively large concns. of Zn was not a practical procedure since high Zn levels drastically diminished plant growth. Annual applications of sewage sludge may not result in undue uptake of Cd present in the sewage but soil levels of Cd will increase. Crop damage by Cd may eventually result if addn. of org. matter is discontinued.
  >> More from SciFinder ^®
  https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaE2cXktFagurs%253D&md5=7510b852311c1c5d48e5cfd66df8e249
15. 15
  Kikuchi, T.; Okazaki, M.; Kimura, S. D.; Motobayashi, T.; Baasansuren, J.; Hattori, T.; Abe, T. Suppressive Effects of Magnesium Oxide Materials on Cadmium Uptake and Accumulation into Rice Grains. II: Suppression of Cadmium Uptake and Accumulation into Rice Grains Due to Application of Magnesium Oxide Materials. J. Hazard. Mater. 2008, 154, 294– 299, DOI: 10.1016/j.jhazmat.2007.10.025
  15
  Suppressive effects of magnesium oxide materials on cadmium uptake and accumulation into rice grains II: Suppression of cadmium uptake and accumulation into rice grains due to application of magnesium oxide materials.
  Kikuchi, Tetsuro; Okazaki, Masanori; Kimura, Sonoko Dorothea; Motobayashi, Takashi; Baasansuren, Jamsranjav; Hattori, Takayuki; Abe, Toshio
  Journal of Hazardous Materials (2008), 154 (1-3), 294-299CODEN: JHMAD9; ISSN:0304-3894. (Elsevier B.V.)
  The objective is to assess the applicability of a com. MgO and a composite material contg. MgO and natural minerals (MgO-SH-A) as the soil amendments for suppression of Cd uptake and accumulation into rice grains. A cultivation expt. of rice plants (Oryza sativa L. cv. Kinuhikari) was conducted in an actual Cd-contaminated alluvial paddy field to evaluate the effectiveness of these materials. The plant available fractions of Cd in the paddy soil significantly decreased by application of com. MgO at 2250 Kg/ha or MgO-SH-A at 4500 Kg/ha. These decreases would be primarily attributed to the increase in soil pH due to applications of the MgO materials because these soil Cd fractions were significantly neg. correlated with the soil pH. Even under a suppressive condition for Cd uptake by rice plants, i.e., continuous flooding of the paddy field around the heading stage, applications of these materials further reduced Cd concn. in brown rice as compared to that from the control. It was concluded that the 2 MgO materials examd. would be effective in preventing Cd contamination of rice grains grown in Cd-polluted paddy fields.
  >> More from SciFinder ^®
  https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXlsFCjs7o%253D&md5=8c779fe9588ca73b1f466c785da13c4c
16. 16
  Xian, X.; Shokohifard, G. I. Effect of PH on Chemical Forms and Plant Availability of Cadmium, Zinc, and Lead in Polluted Soils. Water, Air, Soil Pollut. 1989, 45, 265– 273, DOI: 10.1007/bf00283457
  16
  Effect of pH on chemical forms and plant availability of cadmium, zinc, and lead in polluted soils
  Xian, Xingfu; Gholamhoss in Shokohifard
  Water, Air, and Soil Pollution (1989), 45 (3-4), 265-73CODEN: WAPLAC; ISSN:0049-6979.
  The effect of pH on chem. forms and plant availability of heavy metals in 3 polluted soils was investigated. The soils were adjusted to pH values of 7.0, 6.0, and 4.5, then sequentially extd. so that Cd, Zn, and Pb could be partitioned into 5 operationally defined chem. fractions: exchangeable, carbonate, Fe-Mn oxide, org., and residual. Kidney beans were grown in the soils to investigate plant availability of the metals in relation to changes of their levels in chem. forms resulting from alteration of soil pH. Alteration of pH resulted in changes of chem. forms of the metals in the soils, and at lower pH the changes were more significant. When soil pH values were decreased from 7.0 to 4.55, levels of Cd, Zn, and Pb in exchangeable form increased, decreased in carbonates and decreased slightly in Fe-Mn oxide forms. Their levels in org. and residual forms were unchanged. Although concn. of metals in plants increased with redn. in soil pH values, dry matter yields were also restricted, so that the amt. of metal uptake were almost similar. The uptake rate of the metals in the exchangeable + carbonate forms was the same for the 3 elements in all the cases.
  >> More from SciFinder ^®
  https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3cXitVertw%253D%253D&md5=6b1426cdbd5ad29af9e20c50f0567674
17. 17
  Arao, T.; Kawasaki, A.; Baba, K.; Mori, S.; Matsumoto, S. Effects of Water Management on Cadmium and Arsenic Accumulation and Dimethylarsinic Acid Concentrations in Japanese Rice. Environ. Sci. Technol. 2009, 43, 9361– 9367, DOI: 10.1021/es9022738
  17
  Effects of Water Management on Cadmium and Arsenic Accumulation and Dimethylarsinic Acid Concentrations in Japanese Rice
  Arao, Tomohito; Kawasaki, Akira; Baba, Koji; Mori, Shinsuke; Matsumoto, Shingo
  Environmental Science & Technology (2009), 43 (24), 9361-9367CODEN: ESTHAG; ISSN:0013-936X. (American Chemical Society)
  Rice consumption is a major source of cadmium and arsenic for the population of Asia. We investigated the effects of water management in rice paddy on levels of cadmium and arsenic in Japanese rice grains. Flooding increased arsenic concns. in rice grains, whereas aerobic treatment increased the concn. of cadmium. Flooding for 3 wk before and after heading was most effective in reducing grain cadmium concns., but this treatment increased the arsenic concn. considerably, whereas aerobic treatment during the same period was effective in reducing arsenic concns. but increased the cadmium concn. markedly. Flooding treatment after heading was found to be more effective than flooding treatment before heading in reducing rice grain cadmium without a concomitant increase in total arsenic levels, although it increased inorg. arsenic levels. Concns. of dimethylarsinic acid (DMA) in grain were very low under aerobic conditions but increased under flooded conditions. DMA accounted for 3-52% of the total arsenic concn. in grain grown in soil with a lower arsenic concn. and 10-80% in soil with a higher arsenic concn. A possible explanation for the accumulation of DMA in rice grains is that DMA translocates from shoots/roots to the grains more readily than does inorg. arsenic.
  >> More from SciFinder ^®
  https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtl2qu7rI&md5=895f3bba46d6ed3369a3c9b1375cc917
18. 18
  de Livera, J.; McLaughlin, M. J.; Hettiarachchi, G. M.; Kirby, J. K.; Beak, D. G. Cadmium Solubility in Paddy Soils: Effects of Soil Oxidation, Metal Sulfides and Competitive Ions. Sci. Total Environ. 2011, 409, 1489– 1497, DOI: 10.1016/j.scitotenv.2010.12.028
  18
  Cadmium solubility in paddy soils: Effects of soil oxidation, metal sulfides and competitive ions
  de Livera, Jennifer; McLaughlin, Mike J.; Hettiarachchi, Ganga M.; Kirby, Jason K.; Beak, Douglas G.
  Science of the Total Environment (2011), 409 (8), 1489-1497CODEN: STENDL; ISSN:0048-9697. (Elsevier B.V.)
  Cadmium (Cd) is a nonessential element for human nutrition and is an agricultural soil contaminant. Cadmium soly. in paddy soils affects Cd accumulation in the grain of rice. This is a human health risk, exacerbated by the fact that rice grains are deficient in iron (Fe) and zinc (Zn) for human nutrition. To find ways of limiting this potential risk, we investigated factors influencing Cd soly. relative to Fe and Zn during preharvest drainage of paddy soils, in which soil oxidn. is accompanied by the grain-filling stage of rice growth. This was simulated in temp.-controlled "reaction cell" expts. by first excluding oxygen to incubate soil suspensions anaerobically, then inducing aerobic conditions. In treatments without sulfur addn., the ratios of Cd:Fe and Cd:Zn in soln. increased during the aerobic phase while Cd concns. were unaffected and the Fe and Zn concns. decreased. However, in treatments with added sulfur (as sulfate), up to 34 % of sulfur (S) was pptd. as sulfide minerals during the anaerobic phase and the Cd:Fe and Cd:Zn ratios in soln. during the aerobic phase were lower than for treatments without S addn. When S was added, Cd soly. decreased whereas Fe and Zn were unaffected. When soil was spiked with Zn the Cd:Zn ratio was lower in soln. during the aerobic phase, due to higher Zn concns. Decreased Cd:Fe and Cd:Zn ratios during the grain filling stage could potentially limit Cd enrichment in paddy rice grain due to competitive ion effects for root uptake.
  >> More from SciFinder ^®
  https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXisFWrs7s%253D&md5=ca555c5f9cdaa914396dba8d846cbf28
19. 19
  Williams, P. N.; Lei, M.; Sun, G.; Huang, Q.; Lu, Y.; Deacon, C.; Meharg, A. A.; Zhu, Y.-G. Occurrence and Partitioning of Cadmium, Arsenic and Lead in Mine Impacted Paddy Rice: Hunan, China. Environ. Sci. Technol. 2009, 43, 637– 642, DOI: 10.1021/es802412r
  19
  Occurrence and Partitioning of Cadmium, Arsenic and Lead in Mine Impacted Paddy Rice: Hunan, China
  Williams, Paul N.; Lei, Ming; Sun, Guoxin; Huang, Qing; Lu, Ying; Deacon, Claire; Meharg, Andrew A.; Zhu, Yong-Guan
  Environmental Science & Technology (2009), 43 (3), 637-642CODEN: ESTHAG; ISSN:0013-936X. (American Chemical Society)
  Paddy rice has been likened to nictiana sp in its ability to scavenge cadmium (Cd) from soil, whereas arsenic (As) accumulation is commonly an order of magnitude higher than in other cereal crops. In areas such as those found in parts of Hunan province in south central China, base-metal mining activities and rice farming coexist. Therefore there is a considerable likelihood that lead (Pb), in addn. to Cd and As, will accumulate in rice grown in parts of this region above levels suitable for human consumption. To test this hypothesis, a widespread provincial survey of rice from mine spoilt paddies (n = 100), in addn. to a follow-up market grain survey (n = 122) conducted in mine impacted areas was undertaken to det. the safety of local rice supply networks. Furthermore, a specific Cd, As, and Pb biogeochem. survey of paddy soil and rice was conducted within southern China, targeting sites impacted by mining of varying intensities to calibrate rice metal(loid) transfer models and transfer factors that can be used to predict tissue loading. Results revealed a no. of highly significant correlations between shoot, husk, bran, and endosperm rice tissue fractions and that rice from mining areas was enriched in Cd, As, and Pb. Sixty-five, 50, and 34% of all the mine-impacted field rice was predicted to fail national food stds. for Cd, As, and Pb, resp. Although, not as elevated as the grains from the mine-impacted field survey, it was demonstrated that metal(loid) tainted rice was entering food supply chains intended for direct human consumption.
  >> More from SciFinder ^®
  https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhvFKhtw%253D%253D&md5=70c9e3db703b92d0c1a6c1ab5963d476
20. 20
  Zhuang, P.; Zou, B.; Li, N. Y.; Li, Z. A. Heavy Metal Contamination in Soils and Food Crops around Dabaoshan Mine in Guangdong, China: Implication for Human Health. Environ. Geochem. Health 2009, 31, 707– 715, DOI: 10.1007/s10653-009-9248-3
  20
  Heavy metal contamination in soils and food crops around Dabaoshan mine in Guangdong, China: implication for human health
  Zhuang, P.; Zou, B.; Li, N. Y.; Li, Z. A.
  Environmental Geochemistry and Health (2009), 31 (6), 707-715CODEN: EGHEE3; ISSN:0269-4042. (Springer)
  This study was designed to investigate heavy metal (Cu, Zn, Pb, and Cd) contamination levels of soils, vegetables, and rice grown in the vicinity of the Dabaoshan mine, south China. The concn. of Cu, Zn, Pb, and Cd in paddy soil exceeded the max. allowable concns. for Chinese agricultural soil. The heavy metal concns. (mg kg-1, dry wt. basis) in vegetables ranged from 5.0 to 14.3 for Cu, 34.7 to 170 for Zn, 0.90 to 2.23 for Pb, and 0.45 to 4.1 for Cd. The concns. of Pb and Cd in rice grain exceeded the max. permissible limits in China. Dietary intake of Pb and Cd through the consumption of rice and certain vegetable exceeded the recommended dietary allowance levels. The status of heavy metal concns. of food crops grown in the vicinity of Dabaoshan mine and their implications for human health should be further investigated.
  >> More from SciFinder ^®
  https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhsVers7vJ&md5=921e35c9d95475c092c5865656552873
21. 21
  Yang, Q. W.; Lan, C. Y.; Wang, H. B.; Zhuang, P.; Shu, W. S. Cadmium in Soil-Rice System and Health Risk Associated with the Use of Untreated Mining Wastewater for Irrigation in Lechang, China. Agric. Water Manag. 2006, 84, 147– 152, DOI: 10.1016/j.agwat.2006.01.005
  There is no corresponding record for this reference.
22. 22
  Honma, T.; Ohba, H.; Kaneko, A.; Nakamura, K.; Makino, T.; Katou, H. Effects of Soil Amendments on Arsenic and Cadmium Uptake by Rice Plants (Oryza Sativa L. Cv. Koshihikari) under Different Water Management Practices. Soil Sci. Plant Nutr. 2016, 62, 349– 356, DOI: 10.1080/00380768.2016.1196569
  22
  Effects of soil amendments on arsenic and cadmium uptake by rice plants (Oryza sativa L. cv. Koshihikari) under different water management practices
  Honma, Toshimitsu; Ohba, Hirotomo; Kaneko, Ayako; Nakamura, Ken; Makino, Tomoyuki; Katou, Hidetaka
  Soil Science and Plant Nutrition (Abingdon, United Kingdom) (2016), 62 (4), 349-356CODEN: SSPNAW; ISSN:0038-0768. (Taylor & Francis Ltd.)
  Concns. of arsenic (As) and cadmium (Cd) in rice grains are of public concern for human health. We conducted field expts. to investigate the effects of soil amendment applications, combined with different water management practices, on As and Cd uptake by rice plants (Oryza sativa L. cv. Koshihikari). Prolonged flooding, practiced for pre-heading 3 wk and post-heading 3 wk, led to elevated As concns. in the soil soln. and rice grain. Rainfed water management, in which no irrigation was practiced after midseason drainage until harvest, led to elevated Cd concns. in the soil soln. and rice grain. Application of short-range-order iron hydroxide (IO) reduced As uptake by rice plants, whereas Cd uptake was reduced by the application of converter furnace slag (CFS). However, it was difficult to simultaneously reduce the As and Cd uptake by a single countermeasure of the water management practice or the soil amendment application. Prolonged flooding combined with the application of IO, or rainfed water management with the application of CFS, were promising measures for the simultaneous redn. of As and Cd uptake by rice plants.
  >> More from SciFinder ^®
  https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhtF2hsrjP&md5=7fef3cc4ceb63f8f6f2cc050f2aeed51
23. 23
  Hu, P.; Li, Z.; Yuan, C.; Ouyang, Y.; Zhou, L.; Huang, J.; Huang, Y.; Luo, Y.; Christie, P.; Wu, L. Effect of Water Management on Cadmium and Arsenic Accumulation by Rice (Oryza Sativa L.) with Different Metal Accumulation Capacities. J. Soils Sediments 2013, 13, 916– 924, DOI: 10.1007/s11368-013-0658-6
  23
  Effect of water management on cadmium and arsenic accumulation by rice (Oryza sativa L.) with different metal accumulation capacities
  Hu, Pengjie; Li, Zhu; Yuan, Cheng; Ouyang, Younan; Zhou, Liqiang; Huang, Jiexue; Huang, Yujuan; Luo, Yongming; Christie, Peter; Wu, Longhua
  Journal of Soils and Sediments (2013), 13 (5), 916-924CODEN: JSSOAJ; ISSN:1439-0108. (Springer)
  Purpose Water management affects the bioavailability of cadmium (Cd) and arsenic (As) in the soil and hence their accumulation in rice grains and grain yields. However, Cd and As show opposite responses to soil water content, but information, particularly on irrigation, is missing on a field scale. The purpose of the present study was therefore to find a water management regime that can lower accumulation of both Cd and As in grain without yield loss. Materials and methods Two rice (Oryza sativa L.) cultivars, A16 and A159, with different grain Cd accumulation capacities were employed in field plot expts. with four water management regimes comprising aerobic, intermittent, conventional practice and flooded. The dynamics of Cd and As bioavailability in the soil and Cd and As concns. in roots, straw and grains were detd. at the early tillering, full tillering, panicle initiation, filling and maturity stages of crop growth. Results and discussion The lower water content regimes (aerobic and intermittent) mostly led to higher soil HCl-extractable Cd than the higher soil water content regimes (conventional and flooded). HCl-extractable As in contrast was favored by the higher soil water content treatments. Conventional and flooded irrigation accordingly gave higher plant As concns. but lower Cd compared to aerobic and intermittent irrigation. Cd concns. in roots and straw of both varieties increased with growth stage, esp. in aerobic and intermittent regimes, while As concns. in plants showed little change or a slight decrease. As the water irrigation vol. increased from aerobic to flooded, brown rice Cd decreased from 1.15 to 0.02 mg kg-1 in cultivar A16 and from 1.60 to 0.05 mg kg-1 in cultivar A159, whereas brown rice As increased. Aerobic and flooded treatments produced approx. 10-20 % lower grain yields than intermittent and conventional treatments. Cultivars with low Cd accumulation capacity show higher brown rice grain As than those with high Cd uptake capacity. Conclusions Of the four water management regimes, the conventional irrigation method (flooding maintained until full tillering followed by intermittent irrigation) ensured high yield with low Cd and As in the brown rice and so remains the recommended irrigation regime.
  >> More from SciFinder ^®
  https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXlvVCjsbc%253D&md5=24a83a388fc31b1b72caf0440b22167f
24. 24
  Meharg, A. A.; Norton, G.; Deacon, C.; Williams, P.; Adomako, E. E.; Price, A.; Zhu, Y.; Li, G.; Zhao, F.-J.; McGrath, S.; Villada, A.; Sommella, A.; De Silva, P. M. C. S.; Brammer, H.; Dasgupta, T.; Islam, M. R. Variation in Rice Cadmium Related to Human Exposure. Environ. Sci. Technol. 2013, 47, 5613– 5618, DOI: 10.1021/es400521h
  24
  Variation in Rice Cadmium Related to Human Exposure
  Meharg, Andrew A.; Norton, Gareth; Deacon, Claire; Williams, Paul; Adomako, Eureka E.; Price, Adam; Zhu, Yongguan; Li, Gang; Zhao, Fang-Jie; McGrath, Steve; Villada, Antia; Sommella, Alessia; De Silva, P. Mangala C. S.; Brammer, Hugh; Dasgupta, Tapash; Islam, M. Rafiqul
  Environmental Science & Technology (2013), 47 (11), 5613-5618CODEN: ESTHAG; ISSN:0013-936X. (American Chemical Society)
  Cereal grains are the dominant source of cadmium in the human diet, with rice being to the fore. Here we explore the effect of geog., genetic, and processing (milling) factors on rice grain cadmium and rice consumption rates that lead to dietary variance in cadmium intake. From a survey of 12 countries on four continents, cadmium levels in rice grain were the highest in Bangladesh and Sri Lanka, with both these countries also having high per capita rice intakes. For Bangladesh and Sri Lanka, there was high weekly intake of cadmium from rice, leading to intakes deemed unsafe by international and national regulators. While genetic variance, and to a lesser extent milling, provide strategies for reducing cadmium in rice, caution has to be used, as there is environmental regulation as well as genetic regulation of cadmium accumulation within rice grains. For countries that import rice, grain cadmium can be controlled by where that rice is sourced, but for countries with subsistence rice economies that have high levels of cadmium in rice grain, agronomic and breeding strategies are required to lower grain cadmium.
  >> More from SciFinder ^®
  https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXnsFShu70%253D&md5=6e5ced97dcf54428ebfb416c589ab6d9
25. 25
  Nesbitt, H.; Chan, P.. Rice-Based Farming Systems ; 1997.
  There is no corresponding record for this reference.
26. 26
  Seyfferth, A. L.; McCurdy, S.; Schaefer, M. V.; Fendorf, S. Arsenic Concentrations in Paddy Soil and Rice and Health Implications for Major Rice-Growing Regions of Cambodia. Environ. Sci. Technol. 2014, 48, 4699– 4706, DOI: 10.1021/es405016t
  26
  Arsenic Concentrations in Paddy Soil and Rice and Health Implications for Major Rice-Growing Regions of Cambodia
  Seyfferth, Angelia L.; McCurdy, Sarah; Schaefer, Michael V.; Fendorf, Scott
  Environmental Science & Technology (2014), 48 (9), 4699-4706CODEN: ESTHAG; ISSN:0013-936X. (American Chemical Society)
  Despite the global importance of As in rice, research has primarily focused on Bangladesh, India, China, and the United States with limited attention given to other countries. Owing to both indigenous As within the soil and the possible increases arising from the onset of irrigation with groundwater, an assessment of As in rice within Cambodia is needed, which offers a "base-case" comparison against sediments of similar origin that comprise rice paddy soils where As-contaminated water is used for irrigation (e.g., Bangladesh). Here, we evaluated the As content of rice from five provinces (Kandal, Prey Veng, Battambang, Banteay Meanchey, and Kampong Thom) in the rice-growing regions of Cambodia and coupled that data to soil-chem. factors based on extns. of paddy soil collected and processed under anoxic conditions. At total soil As concns. ranging 0.8 to 18 μg g-1, total grain As concns. averaged 0.2 μg g-1 and ranged from 0.1 to 0.37 with Banteay Meanchey rice having significantly higher values than Prey Veng rice. Overall, soil-extractable concns. of As, Fe, P, and Si and total As were poor predictors of grain As concns. While biogeochem. factors leading to redn. of As(V)-bearing Fe(III) oxides are likely most important for predicting plant-available As, husk and straw As concns. were the most significant predictors of grain-As levels among our measured parameters.
  >> More from SciFinder ^®
  https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXlslSmur4%253D&md5=540059c8c5e5d56f6b9ad550c7a8a54f
27. 27
  Seyfferth, A. L.; Morris, A. H.; Gill, R.; Kearns, K. A.; Mann, J. N.; Paukett, M.; Leskanic, C. Soil Incorporation of Silica-Rich Rice Husk Decreases Inorganic Arsenic in Rice Grain. J. Agric. Food Chem. 2016, 64, 3760– 3766, DOI: 10.1021/acs.jafc.6b01201
  27
  Soil Incorporation of Silica-Rich Rice Husk Decreases Inorganic Arsenic in Rice Grain
  Seyfferth, Angelia L.; Morris, Andrew H.; Gill, Rattandeep; Kearns, Kelli A.; Mann, Jessica N.; Paukett, Michelle; Leskanic, Corey
  Journal of Agricultural and Food Chemistry (2016), 64 (19), 3760-3766CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)
  Arsenic decreases rice yield, and inorg. grain As threatens human health; thus, strategies to decrease rice As are critically needed. Increased plant-available silica (Si) can decrease rice As, yet the source of Si matters. Rice husk, an underutilized and Si-rich byproduct of rice prodn. that contains less labile C and an order of magnitude less As than rice straw, may be an economically viable Si resource to decrease rice As, yet the impact of rice husk incorporation on As in the rice-soil nexus has not been reported. This proof-of-concept study shows that rice husk incorporation to soil (1% wt./wt.) decreases inorg. grain As by 25-50% without neg. affecting grain Cd, yield, or dissolved CH4 levels. Rice husk is a crit. yet perhaps overlooked resource to improve soil quality through enhanced nutrient availability and attenuate human health risks through consumption of As-laden grain.
  >> More from SciFinder ^®
  https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XmsFOntbw%253D&md5=df754ff33edaa92861b978d0f50b612c
28. 28
  Teasley, W. A.; Limmer, M. A.; Seyfferth, A. L. How Rice (Oryza Sativa L.) Responds to Elevated As under Different Si-Rich Soil Amendments. Environ Sci Technol. 2017, 51, 10335– 10343, DOI: 10.1021/acs.est.7b01740
  28
  How Rice (Oryza sativa L.) Responds to Elevated As under Different Si-Rich Soil Amendments
  Teasley, William A.; Limmer, Matthew A.; Seyfferth, Angelia L.
  Environmental Science & Technology (2017), 51 (18), 10335-10343CODEN: ESTHAG; ISSN:0013-936X. (American Chemical Society)
  Several strategies exist to mitigate As impacts on rice and each has its set of tradeoffs with respect to yield, inorg. As content in grain, and CH4 emissions. The addn. of Si to paddy soil can decrease As uptake by rice but how rice will respond to elevated As when soil is amended with Si-rich materials is unresolved. Here, we evaluated yield impacts and grain As content and speciation in rice exposed to elevated As in response to different Si-rich soil amendments including rice husk, rice husk ash, and CaSiO3 in a pot study. We found that As-induced yield losses were alleviated by Husk amendment, partially alleviated by Ash amendment, and not affected by CaSiO3 amendment. Furthermore, Husk was the only tested Si-amendment to significantly decrease grain As concns. Husk amendment was likely effective at decreasing grain As and improving yield because it provided more plant-available Si, particularly during the reproductive and ripening phases. Both Husk and Ash provided K, which also played a role in yield improvement. This study demonstrates that while Si-rich amendments can affect rice uptake of As, the kinetics of Si dissoln. and nutrient availability can also affect As uptake and toxicity in rice.
  >> More from SciFinder ^®
  https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtlShtb3J&md5=b897c6844fb21ef41b9a7113127e0ecd
29. 29
  Sparks, D. L. Methods of Soil Analysis: Chemical Methods; Soil Science Society of America Book Series Number 5; Wiley, 1996, pp 754– 755.
  There is no corresponding record for this reference.
30. 30
  EPA Method 3051A Microwave Assisted Acid Digestion of Sediments, Sludges, Soils, and Oils. EPA Method, 2007, Vol. 3(September), pp 1– 8.
  There is no corresponding record for this reference.
31. 31
  Eckert, D.; Sims, J. T. Recommended Soil PH and Lime Requirement Tests. Analysis 1995, 2006, 19– 26
  There is no corresponding record for this reference.
32. 32
  Schulte, E. E.; Hoskins, B. Recommended Soil Organic Matter Tests Recommended soil testing procedures for the Northeastern united States, 1995, pp 63– 74.
  There is no corresponding record for this reference.
33. 33
  Ross, D. S.; Ketterings, Q. Recommended Soil Tests for Determining Soil Cation Exchange CapacityNortheast (Recommended Soil testing Procedures for the Northeastern United States). Agricultural Experiment Station University: Delaware, Newark, 1995; Vol. 62–69.
  There is no corresponding record for this reference.
34. 34
  Yu, H.-Y.; Liu, C.; Zhu, J.; Li, F.; Deng, D.-M.; Wang, Q.; Liu, C. Cadmium Availability in Rice Paddy Fields from a Mining Area: The Effects of Soil Properties Highlighting Iron Fractions and PH Value. Environ. Pollut. 2016, 209, 38– 45, DOI: 10.1016/j.envpol.2015.11.021
  34
  Cadmium availability in rice paddy fields from a mining area: The effects of soil properties highlighting iron fractions and pH value
  Yu, Huan-Yun; Liu, Chuanping; Zhu, Jishu; Li, Fangbai; Deng, Dong-Mei; Wang, Qi; Liu, Chengshuai
  Environmental Pollution (Oxford, United Kingdom) (2016), 209 (), 38-45CODEN: ENPOEK; ISSN:0269-7491. (Elsevier Ltd.)
  Cadmium (Cd) availability can be significantly affected by soil properties. The effect of pH value on Cd availability has been confirmed. Paddy soils in South China generally contain high contents of iron (Fe). Thus, it is hypothesized that Fe fractions, in addn. to pH value, may play an important role in the Cd bioavailability in paddy soil and this requires further investigation. In this study, 73 paired soil and rice plant samples were collected from paddy fields those were contaminated by acid mine drainage contg. Cd. The contents of Fe in the amorphous and DCB-extractable Fe oxides were significantly and neg. correlated with the Cd content in rice grain or straw (excluding DCB-extractable Fe vs Cd in straw). In addn., the concn. of HCl-extractable Fe(II) derived from Fe(III) redn. was pos. correlated with the Cd content in rice grain or straw. These results suggest that soil Fe redox could affect the availability of Cd in rice plant. Contribution assessment of soil properties to Cd accumulation in rice grain based on random forest (RF) and stochastic gradient boosting (SGB) showed that pH value should be the most important factor and the content of Fe in the amorphous Fe oxides should be the second most important factor in affecting Cd content in rice grain. Overall, compared with the studies from temperate regions, such as Europe and northern China, Fe oxide exhibited its unique role in the bioavailability of Cd in the reddish paddy soil from our study area. The exploration of practical remediation strategies for Cd from the perspective of Fe oxide may be promising.
  >> More from SciFinder ^®
  https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhvFansrfP&md5=229d8fc149318376f19045c6bec03b1e
35. 35
  Yuan, C.; Li, F.; Cao, W.; Yang, Z.; Hu, M.; Sun, W. Cadmium Solubility in Paddy Soil Amended with Organic Matter, Sulfate, and Iron Oxide in Alternative Watering Conditions. J. Hazard. Mater. 2019, 378, 120672, DOI: 10.1016/j.jhazmat.2019.05.065
  35
  Cadmium solubility in paddy soil amended with organic matter, sulfate, and iron oxide in alternative watering conditions
  Yuan, Chaolei; Li, Fangbai; Cao, Wenhua; Yang, Zi; Hu, Min; Sun, Weimin
  Journal of Hazardous Materials (2019), 378 (), 120672CODEN: JHMAD9; ISSN:0304-3894. (Elsevier B.V.)
  We successfully accounted for the dynamics of cadmium (Cd) soly. in paddy soil that contained a realistically low total Cd concn. (0.36 mg kg-1) after submergence and redrying by monitoring multiple chem. and microbial soil properties. The addn. of rice straw promoted greater microbial iron redn. and induced a greater increase in soil pH after submergence, compared to the control and treatments with added gypsum or hematite. Consequently, dissolved Cd decreased to under the detection limit in one week in the straw-amended treatment but remained high even after eight weeks in the other three treatments. The Cd soly. strongly correlated with soil pH and was unlikely to decrease due to Cd pptn. in secondary iron minerals. After five weeks of redrying, the dissolved Cd content was still the lowest, and the putative iron-reducing bacteria Geobacter remained the most abundant in the straw-amended soil. The results suggest that the addn. of org. matter can efficiently immobilize soil Cd at an environmentally realistic concn. by stimulating the microbial redn. of native oxidized soil components after submergence, while adding extra iron oxide or sulfate alone is not effective because it does not eliminate the limitation imposed by electron donors on microbial redn.
  >> More from SciFinder ^®
  https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhtFOjsL%252FP&md5=ff88fbf8693e7248ae0e4d1e71214649
36. 36
  World Health Organization Evaluation of Certain Food Additives and Contaminants; World Health Organization technical report series; World Health Organization, 2013.
  There is no corresponding record for this reference.
37. 37
  Sparks, D. L. Environmental Soil Chemistry; Academic Press, 2003.
  There is no corresponding record for this reference.
38. 38
  Bradley, S. B.; Cox, J. J. Heavy Metals in the Hamps and Manifold Valleys, North Staffordshire, U.K.: Distribution in Floodplain Soils. Sci. Total Environ. 1986, 50, 103– 128, DOI: 10.1016/0048-9697(86)90354-2
  38
  Heavy metals in the Hamps and Manifold valleys, North Staffordshire, U.K.; distribution in floodplain soils
  Bradley, S. B.; Cox, J. J.
  Science of the Total Environment (1986), 50 (), 103-28CODEN: STENDL; ISSN:0048-9697.
  Historic mining for base metals in the catchment of the River Hamps and of the River Manifold in North Staffordshire has left a legacy of floodplain soils which are contaminated with heavy metals. The principal mines in the catchments yielded large quantities of Cu ore, esp. between 1760 and 1790, and some floodplain soils contain >2000 mg Cu/kg; they also contain elevated concns. of Pb, Zn, and Cd. Background concns. of these metals, as detd. by statistical anal., are (kg-1): 52 mg Pb; 145 mg Zn; 17 mg Cu; and 0.40 mg Cd in the whole soil and 200 mg Pb; 251 mg Zn; 182 mg Cu; and 6.76 mg Cd in the fraction <63 μm. Although the mines are sepd. by only 5 km there is a significant difference in the Pb/Cu ratio between the 2 catchments, probably due to a variation across the mineralization. Metal levels in the floodplain soils decrease away from the mine in the order Pb > Cd > Zn > Cu in the Manifold, and Pb > Cu > Cd > Zn in the Hamps. Reprocessing of spoil heaps on the Manifold affected the spectrum of particle sizes supplied to the river, and sediments are finer than those on the Hamps. Also, the extn. of metals during reprocessing has resulted in the sand fraction being depleted. This contrast between an enhanced supply of fine sediments in the Manifold and predominantly coarse in the Hamps is manifest in the floodplain landforms deposited during the mining era. Fine sediments have accumulated by vertical accretion in the Manifold, while coarse sediments were deposited by lateral accretion as gravel splays on the Hamps, i.e. sheets of coarse sediment on the floodplain.
  >> More from SciFinder ^®
  https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL28XksVWkuro%253D&md5=db7652fefa44532e9c43301d8fed8688
39. 39
  Holmgren, G. G. S.; Meyer, M. W.; Chaney, R. L.; Daniels, R. B. Cadmium, Lead, Zinc, Copper, and Nickel in Agricultural Soils of the United States of America. J. Environ. Qual. 1993, 22, 335– 348, DOI: 10.2134/jeq1993.00472425002200020015x
  39
  Cadmium, lead, zinc, copper, and nickel in agricultural soils of the United States of America
  Holmgren, G. G. S.; Meyer, M. W.; Chaney, R. L.; Daniels, R. B.
  Journal of Environmental Quality (1993), 22 (2), 335-48CODEN: JEVQAA; ISSN:0047-2425.
  Surface soil samples from 307 different soil series were analyzed for Pb, Cd, Zn, Cu, Ni, cation exchange capacity (CEC), org. C, and pH in the course of a study of trace element uptake by major agricultural crops. The soil data are summarized statistically and in map form to show their interactions and generalized geog. distribution patterns. Amts. of all five metal elements are generally low in the Southeast. A regional high of about 15 mg/kg Pb covers the Mississippi, Ohio, and Missouri River valleys. Higher values for other elements are generally concd. in the West and in the lower Mississippi River Valley. Max. Cd levels were found in soils of the coast ranges of central and southern California. Copper levels are noticeably higher in org. soil areas of Florida, Oregon, and the Great Lakes. Nickel and Cu concns. are high in serpentine soil areas of California. Nickel levels are also somewhat higher in the glaciated areas of the northern great plains and in northern Maine. For the entire dataset, the values of the min.-max., 5th, 50th, and 95th percentiles are as follows: (mg/kg dry soil) Cd, <0.005 to 2.0, 0.036, 0.20, 0.78; Pb, 0.5 to 135, 4.0, 11, 23; Zn 1.5 to 264, 8.0, 53, 126; Cu 0.3 to 495, 3.8, 18.5, 95; Ni, 0.7 to 269, 4.1, 18.2, 57; pH (pH units) 3.9-8.9, 4.7, 6.1, 8.1; CEC (cmol/kg) 0.6 to 204, 2.4, 14.0, 135; and org. C % 0.09 to 63, 0.36, 1.05, 33.3. Metal levels generally increased with increasing clay concn.
  >> More from SciFinder ^®
  https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2cXns1yn&md5=882e7e596ef37f6b9fafa94c503a0ab8
40. 40
  San, V.; Spoann, V.; Schmidt, J. Industrial Pollution Load Assessment in Phnom Penh, Cambodia Using an Industrial Pollution Projection System. Sci. Total Environ. 2018, 615, 990– 999, DOI: 10.1016/j.scitotenv.2017.10.006
  40
  Industrial pollution load assessment in Phnom Penh, Cambodia, using an industrial pollution projection system
  San, Vibol; Spoann, Vin; Schmidt, Johannes
  Science of the Total Environment (2018), 615 (), 990-999CODEN: STENDL; ISSN:0048-9697. (Elsevier B.V.)
  Approx. 56% out of the total 1302 Cambodian firms are operated in the Capital city of Cambodia. The necessary information on industrial pollution to set strategies, priorities and action plans on environmental protection issues is absent in Cambodia. In the absence of this data, effective environmental protection cannot be implemented. The objective is to est. industrial pollution load using the Industrial Pollution Projection System, a rapid environmental management tool for assessment of pollution load, to produce a scientific rational basis for prepg. future policy direction to reduce industrial pollution in Phnom Penh city. Factory data between 1994 and 2014 obtained from the Ministry of Industry and Handicraft of Cambodia were used in our study. Due to the high no. of employees, the total environmental load generated in Phnom Penh city was estd. to be 476,981 Mg in 2014. Phnom Penh city generated 189,109 Mg VOC, 165,411 Mg of toxic chems. to air, 38,523 Mg of toxic chems. to land, and 28,968 Mg SO2 in 2014. The results of the estn. show that the Textiles and Apparel sector was the highest generators of toxic chems. into land and air, and toxic metals into land, air and water, while the Basic Metal sector was the greatest contributor of toxic chems. to water. The Textiles and Apparel sector alone emitted 436,016 Mg of total pollution load. The results indicate that the Dangkao and Meanchey districts were the greatest emitters of all pollutants in Phnom Penh. The results suggest that redn. in industrial pollution could be achieved by focusing on the most polluting sectors and areas. Adopting waste minimization strategies, which include cleaner prodn. processes, will not only reduce the cost of controlling pollution, it will also make manufg. more efficient thereby increasing profits while reducing pollution load in the long run.
  >> More from SciFinder ^®
  https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhs1elsrzP&md5=f26d02506ca5a0dca852c2758d9dfa3f
41. 41
  Inahara, M.; Ogawa, Y.; Azuma, H. Countermeasure by Means of Flooding in Latter Growth Stage to Restrain Cadmium Uptake by Lowland Rice [Oryza Sativa]. AGRIS 2007, 78, 149– 155, DOI: 10.20710/dojo.78.2_149
  There is no corresponding record for this reference.
42. 42
  Gerson, H.; Shneider, D.; Dabek, P.; Dominguez, M.; Raftopoulos, A.; Zhang, B.; Bostick, B. Interns Find Links Between Climate and Arsenic Levels in Rice. 2020.https://news.climate.columbia.edu/2020/09/02/climate-arsenic-levels-rice/ (accessed on January 21, 2021).
  There is no corresponding record for this reference.
43. 43
  Arao, T.; Ae, N. Genotypic Variations in Cadmium Levels of Rice Grain. Soil Sci. Plant Nutr. 2003, 49, 473– 479, DOI: 10.1080/00380768.2003.10410035
  43
  Genotypic variations in cadmium levels of rice grain
  Arao, T.; Ae, N.
  Soil Science and Plant Nutrition (Tokyo, Japan) (2003), 49 (4), 473-479CODEN: SSPNAW; ISSN:0038-0768. (Japanese Society of Soil Science and Plant Nutrition)
  To identify rice grain genotypes with a lower cadmium content, 49 cultivars of rice were tested under upland conditions, using two types of soils contaminated with cadmium (A: alluvial and B: volcanic ash soil) in 1999 and 2000. Results of ranking of grain cadmium concns. were similar between these 2 yr. NIPPONBARE, KOSHIHIKARI, and HU-LO-TAO belonged to the rice grain group with the lowest cadmium contents. KASALATH could be categorized as a variety with a medium cadmium content, hereafter referred to as "medium cadmium variety," and MILYANG23 and PEH-KUH-TSAO-TU as varieties with high cadmium contents, hereafter referred to as "high cadmium varieties.". These five varieties except for HU-LO-TAO from the above six typical varieties were grown in submerged pots (paddy conditions), and the ranking of the grain cadmium content was almost the same as that in the upland condition pots. These results imply that it may be possible to select paddy rice varieties with a low cadmium content even when growth occurred under upland conditions. The possibility of screening for lower cadmium content in rice grain in soln. culture was examd. The shoot cadmium concns. in soln. culture were not significantly lower in NIPPONBARE and KOSHIHIKARI than those of MILYANG23 and PEH-KUH-TSAO-TU after 4 d of cadmium addn. Only PEH-KUH-TSAO-TU showed a higher shoot cadmium concn. than the other varieties after 27 d of cadmium addn. Thus, as a preliminary evaluation, a screening method using soln. culture would not be suitable for detecting genotypes with a low cadmium content in grain within 1 mo after cadmium addn. These results suggest that the status of available cadmium in soil differs from that of available cadmium in soln. culture. Cadmium distribution for grain (i.e., grain cadmium content ratio to total uptake in the terrestrial part of plants) was evaluated among these 5 varieties. KASALATH absorbed a relatively high amt. of cadmium, although cadmium distribution to grain in KASALATH was the lowest among the 5 varieties. On the other hand, in MILYANG23, a much higher amt. of cadmium was translocated to the grain than in the other 4 varieties, suggesting the existence of genetic variability in cadmium translocation from shoots to grains.
  >> More from SciFinder ^®
  https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXnsVSmtbk%253D&md5=ecedadea881ef576786f5d7e567ea279
44. 44
  Zhao, F.-J.; Wang, P. Arsenic and Cadmium Accumulation in Rice and Mitigation Strategies. Plant Soil 2020, 446, 1– 21, DOI: 10.1007/s11104-019-04374-6
  44
  Arsenic and cadmium accumulation in rice and mitigation strategies
  Zhao, Fang-Jie; Wang, Peng
  Plant and Soil (2020), 446 (1-2), 1-21CODEN: PLSOA2; ISSN:0032-079X. (Springer)
  A review. Background: Arsenic (As) and cadmium (Cd) are two toxic elements that have a relatively high risk of transfer from paddy soil to rice grain. Rice is a major dietary source of these two elements for populations consuming rice as a staple food. Reducing their accumulation in rice grain is important for food safety and human health. Scope: We review recent progress in understanding the biogeochem. processes controlling As and Cd bioavailability in paddy soil, the mechanisms of their uptake, translocation and detoxification in rice plants, and strategies to reduce their accumulation in rice grain. Similarities and differences between the two elements are emphasized. Some knowledge gaps are also identified. Conclusions: The concns. of As and Cd in rice grain vary by three orders of magnitude, depending on the bioavailability of the two elements in soil, rice genotype and growing conditions. The redox potential in paddy soil has a profound but opposite effect on As and Cd bioavailability, whereas soil pH affects Cd bioavailability more than As bioavailability. A no. of key genes involved in As and Cd uptake, translocation, sequestration, and detoxification in rice have been characterized. Allelic variations of several genes underlying the variations in Cd accumulation have been identified, but more remains to be elucidated, esp. for As. Two types of strategies can be used to reduce As and Cd accumulation, reducing their bioavailability in soil or their uptake and translocation in rice. Reducing the accumulation of both As and Cd in rice simultaneously remains a great challenge.
  >> More from SciFinder ^®
  https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXit1Gqt7vN&md5=608a963326f389dac819019028c61a0c

STEP 1:

STEP 2:

Rice Cd Levels in Cambodia Ranged 3 Orders of Magnitude due to Season and Soil Cd LevelsClick to copy article linkArticle link copied!

ACS Omega

License Summary*

Abstract

License Summary*

License Summary*

License Summary*

License Summary*

License Summary*

Introduction

Results

Rice Grain, Rice Straw, and Soil Cd Concentrations

Figure 1

Relation between Plant Cd and Soil Parameters

Figure 2

Figure 3

Discussion

Human Health Implications

Geographical Location

Seasonality

Soil Chemical Factors

Experimental Section

Sample Collection and Preparation

Rice Cd Analysis

Soil Sample Analysis

Statistical Analysis

Author Information

Acknowledgments

References

Cited By

ACS Omega

License Summary*

Article Views

Altmetric

Citations

Recommended Articles

Abstract

Figure 1

Figure 2

Figure 3

References

Rice Cd Levels in Cambodia Ranged 3 Orders of Magnitude due to Season and Soil Cd Levels
Click to copy article linkArticle link copied!