Children's health impact in a smelter site area in China: modeling approaches for the identification and ranking of the most relevant lead exposure routes.

Abstract

Elevated blood lead levels (BLLs) in children still represent a major public health problem worldwide. In China, children's lead (Pb) exposure assessment constitutes a priority issue for research, also due to the scarce availability of human biomonitoring data and limited detailed exposure assessments outside urban areas. This work aims to analyze children's health impact by exploiting exposure modeling approaches to identify the most relevant Pb sources and exposure routes for 0-7-year-old children in a historical Pb-Zn smelter site in Yunnan province (southwestern China), characterized by heavy environmental pollution conditions. For this purpose, two exposure modeling tools, the Integrated Exposure Uptake Bio-Kinetic and MERLIN-Expo, were applied, using measured Pb concentrations in environmental media and food items from a local field campaign as input data. Simulated BLLs, including probabilistic estimates, were obtained and verified against real biomonitoring data from the literature. Model results for the simulated exposure scenario indicate significantly high children's BLLs (>10 µg/dl), which reflect the elevated Pb concentrations measured in environmental matrices and are mostly in agreement with previous biomonitoring data from the region. Moreover, soil and dust ingestion resulted to be the dominant exposure pathway, contributing more than 70% to the overall Pb exposure in children in all investigated scenarios. This work showed how tools for internal exposure modeling can contribute to Pb exposure assessment as complementary tools to demanding and invasive biomonitoring studies and can help identify priority exposure routes for improving risk management.