Blood Lead Levels in South African Inner-City Children

Abstract

Little is known about childhood lead absorption in South Africa. In this study a cross-sectional analytic survey was carried out to determine the blood lead levels and associated risk factors for inner-city, first-grade schoolchildren. Blood lead analyses, hematological and anthropometric measurements were conducted, and a pretested questionnaire was administered to parents to identify risk factors for lead exposure. In a detailed environmental study, daily air and dust samples were collected over a period of 1 year from several sites in the study area, contemporaneously with the blood and questionnaire surveys. Spatial and temporal variations in atmospheric lead were determined. It was found that 13% of mixed race children, but no white children, had blood lead levels greater than or equal to 25 micrograms/dL, the U.S. action level. Air lead levels averaged around 1 microgram/m3, and dust lead levels ranged from 410 to 3620 ppm. Environmental lead levels were significantly elevated near heavy traffic, where Environmental Protection Agency standards were exceeded mainly during winter months. Baseline exposure was of significance in influencing blood lead levels of children attending schools in direct proximity to heavy traffic, where blood lead levels were elevated irrespective of other influencing factors. Primary and secondary preventive measures are urgently needed in South Africa to reduce environmental lead exposure. At the time of the study, South Africa had one of the highest levels of lead in gasoline in the Western World, namely, 0.836 g/L. Although levels have subsequently been reduced, this is typical of the situation in many African countries today.