Health effects in children aged 3–6 years induced by environmental lead exposure

Objectives To investigate the involvement of oxidative damage in lead-induced toxicity in children aged 3–6 years and to enlighten whether oxidative stress indicators are correlated with the known indices of lead toxicity. Methods Blood samples were collected from 408 subjects (217 boys and 191 girls) in the urban kindergartens. The age range of the subjects was 3–6 years. Blood lead levels (BLLs) were analyzed by flameless atomic absorption spectrophotometry. Activities of δ-aminolevulinic acid dehydratase (ALAD), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and contents of glutathione (GSH) in erythrocyte and levels of plasma malondialdehyde (MDA) were analyzed spectrophotometrically in these children. Results Children with BLLs >or=100 μg/L had significantly decreased erythrocyte ALAD activities and increased plasma MDA levels compared to the children with BLLs <100 μg/L. No significant changes were observed in erythrocyte SOD and GSH-Px activities and GSH levels associated with elevated BLLs in these children. Conclusion Present data indicate that oxidative damage could be induced by lead in children with BLLs >or=100 μg/L, and this may partly be attributed to the inhibited ALAD activities. Statistically significant changes of oxidative stress parameters in preschool children while BLLs were more than 100 μg/L could be implicated that oxidative damage might contribute to lead-induced intellectual impairment.