Wednesday, November 7, 2007 - 10:30 AM
326-5
WTRs as a Remedial Agent For Arsenic-Contaminated Soils: In-Vitro and in-vivo studies.
Rachana Nagar1, Dibyendu Sarkar1, Konstantinos C. Makris2, Rupali Datta1, and Victor L. Sylvia3. (1) University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249, (2) Univ. Of Texas, One UTSA Circle, San Antonio, TX 782549, (3) University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, TX 78229
Earlier incubation and greenhouse studies in our laboratory indicated that drinking-water treatment residuals (WTRs) are effective in reducing soil arsenic (As) bioaccessibility. The main objective of this study was to establish a human health risk assessment protocol (in-vivo and in-vitro studies) that illustrates the beneficial use of WTRs in remediating As-contaminating soils. The in-vivo study was performed using 6-week old male BALB/c mice. Mice were fed with soil slurry (1.4 to 7.3 mg As kg-1 BW) using the gavage method. Blood and stomach samples were collected at 1 and 24 hrs after feeding. Urine and excreta were collected at time 0 (before feeding) and 24 hrs after feeding. In-vivo relative As bioavailability (RBA) in WTR and WTR-amended soils ranged from 5-10% and 20-30% respectively; both being significantly (p< 0.05) lower than the control soils (without WTRs). Significant (p<0.05) linear correlations (r2 = 0.72 and 0.68) were observed between in-vitro (stomach and intestine phases, respectively) and in-vivo RBA data obtained from mice blood. Arsenic RBA concentrations in the gastric phase from in-vivo data were linearly correlated (r2 = 0.60, p<0.05) with the corresponding in-vitro. Results obtained from this study will be highly useful in designing cost-effective remedial strategies for arsenic contaminated soils.
Key words: Arsenic, drinking- water treatment residuals, relative bioavailability (RBA), in-vitro, in-vivo.