Blood lead levels and risk factors for lead toxicity in children from schools and an urban slum in Delhi

This cross-sectional study was conducted to estimate the mean blood lead levels (BLL) and prevalence of lead toxicity in a representative sample of schoolchildren and children residing in an urban slum. In addition, the association of potential environmental risk factors with elevated BLL was studied. Children aged 4-6 years were selected from schools of the South zone of Delhi (n = 125) and from an urban slum (n = 65). Risk factors were recorded using a pre-tested questionnaire and blood lead and zinc protoporphyrin (ZPP) levels were estimated. The mean BLL was 7.8 mug/dl (SD 3.9) and the proportion of children with blood lead greater than or equal to 10 mug/dl was 18.4 per cent. Distance of the residence or school from a main road appeared to be associated with higher blood lead concentrations, but these differences were not statistically significant. In our setting, vehicular pollution may be a major contributing factor in lead contamination of the environment.