Blood lead levels (BLLs), exposure pathways and health impacts in South Asia: a comprehensive review

Abstract

Abstract Lead remains a pervasive toxicant in South Asia. We compiled published blood lead levels (BLLs), food, and environmental lead concentrations from South Asia (India, Bangladesh, Pakistan, Nepal and Sri Lanka) to identify the primary sources contributing to population exposure. Across all regions, reported BLLs frequently exceeded the current Centers for Disease Control and Prevention (CDC) reference value of 3.5 µg/dL. Elevated BLLs were consistently associated with adverse health outcomes, including neurocognitive impairment, anemia, hypertension, renal and hepatic dysfunction, and oxidative and genotoxic effects in both children and adults. Comparative assessment of lead concentrations across environmental media indicated significant contamination of dietary sources, with rice, vegetables and spices emerging as a major contributor to population exposure. However, airborne lead also played major role particularly in densely populated industrial settings. Correlation analysis demonstrated positive association between literature derived BLL and lead concentration in numerous environmental media, emphasizing the cumulative influence of multi pathway lead exposure. Despite heterogeneity in study designs and geographic coverage, the findings confirmed that non-fuel sources now dominate the lead exposure in South Asian regions. This review highlights the critical need for enhanced food safety regulations, reinforced environmental monitoring and targeted public health interventions in order to mitigate lead exposure and its related health impacts especially in vulnerable populations.