Chemical Analysis of Soils: An Environmental Chemistry Laboratory for Undergraduate Science Majors

Successful management of conflicting uses of soils, which include food production as well as disposal of hazardous wastes, requires an understanding of soil characteristics that affect the mobility and fate of soil contaminants and nutrients. Soil chemistry, however, is often neglected in environmental chemistry courses. This laboratory exercise is designed to make this topic more accessible to instructors who teach environmental chemistry laboratories, as well as to their students.

In this laboratory exercise, undergraduate science students evaluate soil samples for various parameters related to suitability for crop production and capability for retention of contaminants. The lab emphasizes the heterogeneous nature of soil and the difficulty of obtaining representative samples for analysis. One of the first steps in any chemical analysis is to obtain a representative analytical sample from a bulk sample, yet undergraduate students rarely do this in practice. In this lab, students attempt to obtain a representative analytical sample from a large soil sample. They compare their individual data with the mean and standard deviation compiled from the whole class. Soil water, calcium carbonate, organic matter, pH, and salinity are measured. Soil texture and octanol-water partitioning are demonstrated.