Exposure of lead amongst primary school children in fishing communities in South Africa

Abstract

BACKGROUND: Lead is one of the most widely used and studied heavy metals. Lead has a number of serious detrimental effects including those related to the nervous system (seizures, ataxia) heamotological system (anaemia) and renal system. The severity and prognosis of diseases related to lead exposure is more pronounced in children, even with very low blood levels. Anecdotal reports of lead melting to make fishing sinkers in South African subsistence fishing communities prompted the conduct of an epidemiological study in four South African fishing villages to investigate the extent of lead melting and the associated risks in children. METHODS: A cross sectional analytical study was conducted. The study was conducted in two schools located along the western (Atlantic Ocean) coast of South Africa (HP Williams Primere in Stompneusbaai and NGK Primary School in Elands Bay) and in two schools located along the southern (Indian Ocean) coast of South Africa Bertie Barnard School in Stilbaai, Struisbaai Primere School in Struisbaai. Blood samples were collected for lead content analysis, and anthropometric measurements were taken. Questionnaires were administered to obtain information about socio-economic status and risk factors for lead exposure. A total of 196 children from grade 0, 1 and 2 were included in the study. RESULTS: Blood lead levels in the sample ranged from 1.9 to 22.4 μg/dl. Central tendency of the blood lead level demonstrated an arithmetic mean of 6.87 μg/dl (95% CI: 6.36 to 7.37 μg/dl) and a median of 6.1 μg/dl. More than half of the children in the study had blood lead levels between 5.0 - 9.9 μg/dl, whilst 13% that had levels higher than 10 μg/dl. Age, sex and ethnicity was not significantly associated with high blood lead levels whilst, lead melting practices and interaction of children with pets were strongly associated with high blood lead levels in children. Multivariate analysis showed that the presence of a fisherman in the household and children watching smelting were significantly associated with higher blood lead levels. Village remained a confounding variable in the model. CONCLUSIONS: This study is the first report on blood lead levels in fishing villages on the African continent and provides evidence that lead is still used widely as the primary substance used to make fishing sinkers. The prevalence of plumbism was high at 75%. Policy and awareness is needed to address this neglected public health concern.