Arsenate and arsenite levels in the coastal and estuarine waters of Goa

Abstract

Arsenate and arsenite concentrations were determined in estuarine and coastal waters around Goa during the pre-monsoon months (February to April). Arsenate was found to be the dominant form in both the systems. In the estuarine waters, arsenate varied from less than 1 mu g/l to 21.75 mu g/l (av. 5.28 mu g/l) and arsenite from less than 1 mu g/l to 18.75 mu g/l (av. 2.54 mu g/l) while in coastal waters, it ranged from less than 1 mu g/1 to 24.0 mu g/l (av. 5.91 mu g/l) and arsenite from less than 1 mu g/1 to 9.0 (mu g/1 (av. 1.43 mu g/l). A few estimations of the total arsenic in the estuarine and coastal sediments indicate marked accumulation of this element (4 -14 ppm). The observed variations in the waters are attributed to the differential intensities of chemical and biological oxidation in the system, microbial reduction and the mixing processes