The Sorption of Arsenic Influence on Characteristics of Taxonomically Distinct Soils.

The objective of this project is to develop a unique competence using soil taxonomy to predict complex processes in soils that are often difficult to detect and measure. We define complex processes as those that can only be resolved by decomposing the data set from a large number of variables to a smaller number of variables, representing those variables that are best suited to the data set. These reduction techniques allow for the observation of new information regarding the more subtle structure already present within the data.The sorption behavior of arsenic (As) was investigated with different, taxonomically distinct soil types. By using taxonomically distinct soils, we sought to connect a complex process, such as arsenic sorption, to quantitative descriptions of these different soil types obtained from their chemical, physical, and biological soil characteristics.

Once verifying the NRCS designations in the field for the selected location using a soil probe, a composite sample was collected at each location ranging from 25-50 cm in depth, and transported back to the laboratory for processing and physical and chemical characterizations. Sorption isotherm studies were conducted using batch techniques with arsenic concentrations ranging from 0-100 ppm with 0.3mM CaCl2 as the background electrolyte. Preliminary results showed strong multivariate structure emphasizing the taxonomic differences among the selected soil types. Initial results suggest that certain chemical properties in the soils such as: iron (Fe), manganese (Mn), and carbon content influence the arsenic sorption and metalloid interaction with each soil. The differences in physical structure and chemical properties between the soil orders play a major role in arsenic sorption.