Arsenic contamination levels in drinking water sources in mining areas in Lake Victoria Basin, Tanzania, and its removal using stabilized ferralsols

Abstract

Arsenic contamination in drinking water is a public health problem all over the World especially in mining areas. The study herein reported assessed the concentration levels of arsenic in some drinking water sources in the mining areas in the Lake Victoria Basin and investigated the potential for its removal by adsorption using stabilized ferralsols. Randomly collected samples from drinking water sources were analysed for arsenic, phosphorus, iron and pH. Arsenic was detected in 58% of water sources surveyed and 41% of them had arsenic levels equal to or exceeding the Tanzania Drinking Water Quality Standards threshold value of 10 ppb. Arsenic mobilization is suspected to be due to oxidation of arsenopyrite after exposure of the ore to the air partly due to mining activities. Laboratory experiments have shown that adsorption using stabilized ferralsols
(1:1 mixture of Portland cement and ferralsols on dry weight basis) is capable of removing up to 97% of arsenic independent of water pH and initial contaminant concentrations used during the study. In view of this, adsorption using stabilized ferralsols may be considered to be a promising technology for removing arsenic from drinking water.

Keywords: Arsenopyrite, Portland cement, Adsorption isotherms, Groundwater, Efficiency.

International Journal of Biological and Chemical Sciences Vol. 2 (4) 2008: pp. 389-400