Biogeochemistry of Arsenic and Its Extraction From SoilEPA Grant Number: U915037
Title: Biogeochemistry of Arsenic and Its Extraction From Soil
Investigators: Thomas, John E.
Institution: University of Florida
EPA Project Officer: Manty, Dale
Project Period: January 1, 1996 through December 28, 1999
Project Amount: $102,000
RFA: STAR Graduate Fellowships (1996) RFA Text | Recipients Lists
Research Category: Academic Fellowships , Ecological Indicators/Assessment/Restoration , Fellowship - Earth Sciences
The objective of this research project is to explore potential effective means of remediating arsenic-contaminated soil through extraction, mobilization, or volatilization of arsenic.
The first area of investigation involves chemical complexation and extraction of the arsenical oxyanions (oxygenated negative ions) by an aqueous solution of sodium dodecylsulfate mixed with a highly positive-charged macrocycle (compound containing a ring consisting of 15 atoms) synthesized from vitamin B1. The ability to extract arsenic coupled with the expected biodegradability of the organic extractants makes this system a strong candidate for classical pump-and-treat remediation or other soil flushing/washing procedures. The second thrust of this study involves the biological volatilization of arsenic. Field studies are conducted to assess volatilization rates off the soil surface using soil gas flux collection boxes. The subsurface flux also is determined using depth probes to collect arsenical gases onto activated charcoal. Laboratory studies are conducted to find arsenic volatilization rates under various oxic (oxygenated) conditions for soil and for mineral culture media inoculated with microorganisms isolated from these contaminated soils. This project consists of six distinct phases: (1) site identification; (2) quantification of the amount and location of arsenic in the soil; (3) evaluation of the chemical extraction procedure of arsenic from the different soil types; (4) testing of the soil for biological volatilization of arsenic; (5) isolation and testing of microorganisms responsible for arsenic volatilization; and (6) determination of the rates of arsenic transformation to volatile compounds by these microorganisms under various oxic conditions.