Heavy metal Assessment and Their Speciation in Sediments of Lake Chapala, Mexico.
Abstract
The presence of heavy metals Cd, Pb, Mn, Cr, Fe, Ni, Cu, and Zn in waters and the speciation of Cd, Pb, Cr, Ni, Cu, and Zn in sediments of several sites of the Mexican Lake Chapala as well as some physicochemical parameters reflecting water quality, are presented here. The sites were sampled on March 2007. Metals in sediments and their partition into chemical species was determined between five geochemical phases (exchangeable, carbonates, Fe/Mn oxides, organic matter and residuals) applying the Tessier' s sequential extraction technique. Sediment cores (n=10) taken from the depocenter between the years of 1998 and 1999 allowed evaluation of sediment uniformity (geochemistry, mineralogy and particle distribution). Cadmium, lead and chromium were found to be present significantly in both exchangeable and carbonate fractions in two sites indicating that these metals were introduced to the lake via anthropogenic activities during the period of 1960 through the first quarter of 2006. The Risk Assessment Code was applied to the two sites studied and it was found that both sites pose a high level risk of pollution since the metals bound to exchangeable and carbonate fractions in the cases of Pb and Cd comprise > 45%.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2007
- Bibcode:
- 2007AGUFM.B33C1428G
- Keywords:
-
- 0409 Bioavailability: chemical speciation and complexation;
- 0432 Contaminant and organic biogeochemistry (0792);
- 0458 Limnology (1845;
- 4239;
- 4942);
- 0461 Metals;
- 0478 Pollution: urban;
- regional and global (0345;
- 4251)