Relating tooth‐ and blood‐lead levels in children residing near a zinc–lead smelter in India

Abstract

Lead toxicity particularly affects children because of their increased capacity for absorption and retention. Blood-lead (BPb) levels reflect recent exposure and are of limited value in predicting neurotoxicity, whereas in teeth, lead accumulates over a long period of time and provides an integrated record of lead exposure from intrauterine life until the teeth are shed. The present study aimed to relate tooth-lead (TPb) and BPb levels in children residing near a zinc-lead smelter in India, and to evaluate the effectiveness of primary teeth as bioindicators of life-long lead exposure. The lead levels in primary teeth and blood of 100 children aged between 5 and 13 years, living in the proximity of a zinc-lead smelter were measured by atomic absorption spectrophotometry. The mean levels were tabulated based on village, age, sex and tooth type, and analysed statistically. The mean BPb level was significantly influenced by proximity to the lead source, but not by age or sex. There was no consistent pattern of correlation between BPb and TPb levels. Primary teeth showed significantly high lead levels compared to blood; they reflect cumulative exposure to lead and prove to be better indicators of body lead burden.