Human Exposure to Lead in Selected Areas in Olkalou and Nairobi, Kenya

Abstract

Lead is a multitargeted toxicant, causing toxic effects to almost all organs and systems in the human body. Children are more susceptible to lead poisoning and suffer irreversible neuropsychological and cognitive impairments. WHO estimates that 12 million children in developing countries suffer from some form of permanent brain damage due to lead poisoning. In addition, hundred of millions of children and pregnant women suffer from various toxic effects of lead exposure. Though substantial progress has been made fiom the global response to lead poisoning, chronic exposure to low levels of lead in the environment still remains a serious public health problem particularly in developing countries where occupational lead poisoning is equally not adequately addressed. The problem is exacerbated by lack of appropriate diagnostic facilities. Though several biomarkers are used as effective tools in diagnosis of lead poisoning, measurement of blood lead concentration is regarded as the most reliable for general clinical use and public health surveillance. The World Health Organisation and the United States Center for Disease. Control places a blood lead level (BLL) of l0ug/deciliter of blood as toxic although no threshold levels has been determined due to the observed effects of lead exposure in children. This study was done to determine the prevalence of lead exposure in selected areas of Nairobi and in Olkalou. The latter study site served as a covariate. Blood lead levels were determined in a total number of 308 subjects using anodic stripping voltammetry (ASV). Children and adolescents (individuals aged 20 years and below) made 40% of the study subjects. The results obtained indicated 25% of the study population as exposed to high levels of lead. Agewise, 21% of children and adolescents were exposed to unacceptable levels of lmd. Within the occupational setup of Ziwani Jua kali works, 89% of the workers had BLLs above 10ug/dl. The results of this study indicated significant environmental and occupational human exposure to unacceptable levels of lead in Nairobi. It is recommended that measures to address all sources of lead exposure and eradication of the problem be instituted. Based on the scope of this study, a comprehensive study to assess and identify childhood lead poisoning and the contribution of the various sources of lead, and an audit of industrial lead exposure is recommended.