Abstract

People’s health, behavior and intellect to a certain extent are a function of their environment. One important component of this environment is water, a basic necessity that human beings cannot do without. The water available, however, is not always safe for human consumption due to contamination. Among the many water contaminants, lead (Pb) is one of the most dangerous due to its bio-accumulative nature and high toxicity. Children are most vulnerable to Pb toxicity as their main organs such as the brain and the nervous system are still developing. For them, exposure to even relatively low concentrations can result in reduced intelligence quotient (IQ), learning disabilities and attention deficit disorders, behavioral problems such as delinquency and drug abuse, and such conditions as impaired hearing and mental retardation. The main aim of the present study was to determine Pb concentration in water from hand-dug wells in Kwale County in the coastal region of Kenya. Kwale County hosts a number of schools for mentally disabled and hearing impaired persons, while the coastal region in general has among the lowest literacy levels in the country and the highest incidences of drug abuse. Thirty-seven water samples were randomly collected from selected villages and analyzed for Pb content using a flame atomic absorption spectrophotometer (FAAS). Also analyzed were the water pH and conductivity using portable digital meters. Pb concentration in the water samples ranged from below detection limit to 1.397 mg/L with a mean concentration of 0.330 mg/L. Over 62% of the samples had Pb levels above WHO recommended value of 0.01 mg/L. The pH ranged from 5.8 to 10.4 with a mean value of 9.2 while conductivity ranged from 85.3 to 6060 µs/cm with a mean value of 930.351 µs/cm.

Key words: Lead, well water, intelligence quotient (IQ), mental retardation, deafness, Kwale.