Influence Of Anthropogenic Activities On Sediment Characteristics And Heavy Metal Concentrations In Lake Baringo, Kenya

ABSTRACT

Lake Baringo waters and sediments are being impacted negatively by metal contaminants sourced from the lake’s watershed posing a human and environmental health concern. The main objective was to determine the concentration of heavy metals cadmium (Cd), copper (Cu), mercury (Hg) and lead (Pb) in water and sediments, and to characterize sediments in terms of grain size and total organic carbon and relate them to the heavy metal levels encountered at the sampled sites. 5 sites were selected and samples collected over a period of six months. Water samples were collected in polypropylene bottles and acidified with ultra-pure HNO3 to pH < 2 and stored at 4oC prior to analyses. Sediments were collected using a grab sampler and analyzed for total extractable metals using the multi-acid digestion method. Particle size classification was done by standard method of analysis by sieving and organic carbon (OC) was estimated using the Loss on Ignition (L.O.I) method. Data obtained was tested for normality and homogeneity of variance. Heavy metal concentrations were compared using analysis of variance (ANOVA) to test for differences among sites (α = 0.05). Pearson correlation was used to establish inter metallic relationships. Mean values of the physico-chemical parameters studied for all sites (pooled data) were as follows: E.C. 374.19±0.5μScm-1, pH 7.62±0.03, temperature 28.4±0.15°C, T.D.S. 373.6±0.5 and salinity 0.12±0.05%. There were significant differences between the sites for all parameters measured (p