CONCENTRATIONS OF SELECTED TRACE ELEMENTS IN BOREHOLE WATER AND THEIR IMPLICATIONS FOR HUMAN HEALTH IN ELDORET MUNICIPALITY.

Abstract

Water is a basic human requirement as it is extensively used in everyday life and therefore if contaminated it is detrimental to life and can cause death. This study assessed levels of trace elements; Copper, Chromium and Manganese in borehole waters in Eldoret Municipality Kenya, their temporal variation and implications on human health. Samples were collected in the months of April, May, June and July in the selected boreholes and analysed for the trace metals using standard procedures. During the first visit to the selected boreholes, participants were recruited to the study. Questionnaires were administered from which a health risk assessment using exposure to the trace elements via the drinking water ingestion was worked out. The readings from Global Positioning System (GPS) taken and recorded for each of the boreholes sampled. Atomic Absorption Spectrum (AAS) was used to determine the concentrations of the trace elements and variability was then assessed using SPSS version 12.0 by comparing the results obtained to literature values by WHO/FAO. The results showed low concentration of the trace elements under investigation except for Chromium. In kipkorogot were the concentration of copper was higher than WHO/FAO recommended value and this was attributed to the quarry activities near the borehole. Also the higher Copper concentration in Munyaka was attributed to precipitation and subsequent percolation of contaminated runoff waters from the nearby farms where fertilizers and chemical sprays are normally used. Copper concentration ranged between 0.005 – 0.050 ppm, Chromium ranged between 0.04 – 0.23 ppm and Manganese concentration ranged between 0.0684 – 0.2906 ppm. In 69% of the borehole, concentration of Chromium was high and significantly different from the WHO/FAO values. The implications on the health were however not found to be significant. The health risk resulting from copper and Chromium were highest in Kipkorogot 0.005948 and 0.026813 respectively. Manganese was highest in Kipkaren with a value of 0.035303. However all the health risk values obtained were not significant. The borehole water in Eldoret Municipality needs to be monitored closely because of the variations displayed to minimize the likely health effects that can arise mainly from Copper and Chromium which displayed significant variations. In conclusion the concentration of the trace elements Copper, Manganese and Chromium in the study was generally lower than WHO/FAO recommended values. However there were exceptions which are attributed to the anthropogenic activities within the areas. The health risk implication was not significant for the trace elements studied.