Web Release Date: April 17,
Degradation of Chloroacetanilide Herbicides: The Prevalence of Sulfonic and Oxanilic Acid Metabolites in Iowa Groundwaters and Surface Waters
Received for review December 30, 1997 Revised manuscript received
March 18, 1998 Accepted March 19, 1998 Abstract: Water samples were collected from 88 municipal wells
throughout Iowa during the summer and were collected
monthly at 12 stream sites in eastern Iowa from March
to December 1996 to study the occurrence of the sulfonic
and oxanilic metabolites of acetochlor, alachlor, and
metolachlor. The sulfonic and oxanilic metabolites
were
present in almost 75% of the groundwater samples and
were generally present from 3 to 45 times more frequently
than their parent compounds. In groundwater, the
median
value of the summed concentrations of acetochlor,
alachlor, and metolachlor was less than 0.05 Download the full text:
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and
g/L, and
the median value of the summed concentrations of the six
metabolites was 1.2 g/L. All surface water samples
contained at least one detectable metabolite compound.
Individual metabolites were detected from 2 to over
100
times more frequently than the parent compounds. In
surface
water, the median value of the summed concentrations
of the three parent compounds was 0.13 g/L, and the
median
value of the summed concentrations of the six metabolites
was 6.4 g/L. These data demonstrate the importance
of
analyzing both parent compounds and metabolites to
more fully understand the environmental fate and transport
of herbicides in the hydrologic system.
