Levels of Heavy Metals (Pb, Mn, Cu and Cd) in Water from River Kuywa and the Adjacent Wells

Abstract

Worldwide, over one billion people lack access to clean drinking water, this being attributed to industrial effluents, agricultural chemicals and residential wastes. As such, contaminants in drinking water including heavy metals pose fears on human health especially if levels exceed limits set by WHO and the Kenya Bureau of Standards (KEBS). Water sourced from River Kuywa in Bungoma County, Kenya and its adjacent wells risk heavy metal contamination due to the surrounding industrial and agricultural activities. Never the less, the waters are used for domestic purposes. Water samples from River Kuywa and in adjacent wells were analyzed for Pb, Mn, Cu and Cd during a dry and rainy season employing Flame atomic absorption spectroscopy and ANOVA for instrumental and data analysis respectively. The mean values (mg/l) of Pb, Cu and Cd in water from the river during the two seasons were: Pb (0.57±0.09 - 3.36±1.15), Cu (1.01±0.12-1.92±0.14) and Cd (0.32±0.02-0.99±0.67). In wells, the waters had the ranges: Pb (1.43±0.34-2.43±0.41), Cu (1.39±0.24-1.92±0.14) and Cd (0.35±0.03-0.46±0.03). These were above those set by KEBS and WHO with significant differences noted between seasons (p<0.05). Strategies that would reduce further contamination of water in river Kuywa and in the adjacent wells are called for to intervene for the unforeseen health risks associated with heavy metal poisoning.