Impact of anthropogenic activities on copper and lead levels in Kisumu city soils

Abstract

The sources of heavy metals in the soil are fertilizers, fuel plastics, pigments, motor vehicles exhausts, oils spilt at motor-vehicle mechanic works and paint chips from buildings. The two majorly known heavy metals are copper and lead which are harmful to biota, animals and human beings. The study was conducted in Kisumu City with the aim of determining the concentrations of Cu and Pb in the nine selected sampling sites. In each site 100 g soil samples were collected in triplicates from a 5 cm deep freshly dug hole. Soil samples were collected in a completely randomized design then oven-dried, ground and digested using aquaragia solution for total metallic content and treated in HCl only for bioavailable metal content. All the analysis was performed in the atomic absorption spectrophotometer. The results showed that the total and bioavailable concentrations of Cu ranged between 1.59 to 31.05 ppm and 0.40 to 28.49 ppm while Pb concentrations varied between 8.69 to 119.12 ppm and 7.09 to 91.85 ppm for total and bioavailable respectively. Positive correlation was observed between Cu and Pb concentrations, R2 = 0.293 and 0.570 for total and bioavailable concentrations respectively. Key words: Heavy metals, Kisumu city, total, bioavailable, sampling sites.