The movement; sorption, loss and chemical distribution of arsenic-74 labeled disodium methanearsonate in some Tennessee soils

Author

Michael B. Akins

Date of Award

12-1973

Degree Type

Thesis

Degree Name

Master of Science

Major

Plant, Soil and Environmental Sciences

Major Professor

Russell J. Lewis

Committee Members

Larry Jeffery, James Chambers

Abstract

Radioactive ⁷⁴As disodium methanearsonate (DSMA-⁷⁴As) was used as a resentative compound of the methanearsonate family to study their fate and behavior in soil systems. This compound was produced in the laboratory. Five samples of 4 Tennessee soils of various chemical, physical, and mineralogical properties were used in this study. Sorption of DSMA-⁷⁴As was studied by employment of the batch equilibration technique. Various soil properties (pH, percent clay content, CEC, organic matter content) were related to the soil sorption of DSMA-⁷⁴As in this study. Imposed conditions (alteration of soil pH, phosphorus con-tent) of selected soil properties were related to the soil sorption of DSMA-⁷⁴As. Using laboratory prepared soil columns the leachability and distribution of DSMA-⁷⁴As were determined in the soils and the effect of the imposed conditions were measured. Determination of microbial or chemical induced evolution of gaseous arsenic under imposed conditions of organic matter and moisture was investigated. The distribution of sorbed DSMA-⁷⁴As in the soil was determined by a modified phosphorus procedure. Soils with high clay content and with kaolinite as their major component sorbed the greatest quantities of DSMA-⁷⁴As from solutions containing DSMA-⁷⁴As. The effect of organic matter on sorption could not be measured directly, but it appears to have a positive effect on sorption of DSMA-⁷⁴As. Cation exchange capacity apparently had no direct effect on sorption. In most cases the amount of DSMA-⁷⁴As leached was inversely proportional to the sorption capacity of the soils. The soils with the least amount of clay leached the greatest quantities of DSMA-⁷⁴As. Phosphorus reduced the ability of soil to sorb DSMA-⁷⁴As quite dramat-ically in the batch equilibration experiments and in the soil columns. Acid treatments generally increased the ability of the soil to retain DSMA-⁷⁴As. Sorption of DSMA-⁷⁴As was found to be more dependent upon soil texture and mineralogical composition than pH. Gaseous arsenic evolution was greatest from soils that had received an exogeneous carbon source and maintained under reduced conditions. The chemical distribution of DSMA-⁷⁴As in the soils studied showed that Fe arsenate was the predominant form and Al arsenate was the second most predominant form.

Recommended Citation

Akins, Michael B., "The movement; sorption, loss and chemical distribution of arsenic-74 labeled disodium methanearsonate in some Tennessee soils. " Master's Thesis, University of Tennessee, 1973.
https://trace.tennessee.edu/utk_gradthes/8235