Monitoring of Heavy Metals in Groundwater In Makuyu Division, Maragua District

Abstract

Analytical results have shown that the borehole and well water in Makuyu Division in Maragua District in central Kenya is not polluted and can be consumed readily. The level of the various parameters is low compared to recommended limits. The chemical properties monitoring showed no significant heavy metal pollution in groundwater. The heavy metal concentrations values ranges from 0.0994 – 101450 mg/l for iron, 0.0046 – 1.0190 mg/l for manganese, 0 – 0.0588 mg/l for titanium, 0.0011 – 0.0142 mg/l for copper, 0.0027 – 0.1692 mg/l for zinc, 0.0011 – 0.0016 mg/l for strontium, 0.0012 – 0.0043 mg/l for yttrium and 0.0013 – 0.0043 mg/l for zirconium. The concentration of iron, manganese, copper, zinc, selenium, titanium, strontium, yttrium and zirconium were determined in filtered water after pre-concentration with ammonium pyrolidine dithiocarbonate APDC using X-ray fluorescence analysis (XRFA). The values obtained showed no significant heavy metals pollution in groundwater. The trace metal concentrations in filtered water were below the maximum permissible limits for drinking water as given by the World Health Organization (1993). It is only in Kamahuha Girls High School borehole where the concentration of iron and manganese were above the WHO standards. The XRFA technique was found to be a fast, precise, accurate and reliable method of water analysis. Recent studies have indicated that toxicity of metals such as copper and zinc is primarily due to the presence of the free metal iron and thus may not be directly related to the total metal concentration (Shepherd, B K et al. 1980).