Assessment of Heavy Metals Pollution in Urban Soils and the Implications to Consumers Health

Abstract

Elevated levels of metals due to anthropogenic activities are a cause of environmental concern because of their effects on human health. Eldoret Municipality, in Kenya, is one of the fastest growing municipalities with both industrial and agricultural developments.  The study aimed at determining the concentration of five elements namely zinc (Zn), lead (Pd), copper (Cu), chromium (Cr) and cadmium (Cd) in five sample sites within the municipality and established the possible health risks in the residents. Measured concentrations of Zn, Pb, Cr, Cu and Cd in surface horizon soils were used to estimate the geochemical load indices and their spatial distribution. Four soil samples were collected monthly from each sample site on the same farms totaling 200 soil samples. The samples were dried, ground and sieved for metal digestion using varied acids in the laboratory and analysis was done against metal standards using Atomic Absorption Spectrometry (AAS). Only Cd concentration (0.0286mg/kg) in all sites was above the recommended unpolluted soils. Epidemiological data were obtained from the residents and hospitals to establish associated health risks. Determination of metals’ combined effects using multivariate Principal Component Analysis showed that varying concentrations of Zn and Pb tended to increase incidences of cancer, hypertension and stroke. Metals Zn, Pb and Cu concentrations correlated with development of cardiovascular diseases. Awareness rising to residents of Eldoret Municipality on high Cd concentration in the soil and use of alternative forms of fertilizers and related chemicals with low Cd content is recommended.

Keywords: Elements, Human Health, Spatial Distribution, Urban Soils