Childhood Lead Exposure in an Industrial Town in China: Coupling Stable Isotope Ratios with Bioaccessible Lead

Fingerprinting based on stable isotopes of lead (Pb) in blood and environmental media helps to identify Pb exposure pathways in children. However, previous studies used stable isotopes of total Pb in media. In this study, a wire rope production town in China (Zhuhang) was selected for investigating the effectiveness of using isotope ratios in bioaccessible Pb to identify childhood Pb exposure pathways. Blood Pb levels of 115 children in Zhuhang were 1.7-20.4 mu g dL(-1), averaging 6.1 +/- 3.2 mu g dL(-1) (mean +/- standard deviation), and were similar to 1.6 times the national average in China (3.9 +/- 1.8 mu g dL(-1)). Among different environmental media (housedust, soil, PM10, vegetables, rice, and drinking water), housedust (695 +/- 495 mg kg(-1)) and vegetables [0.36 +/- 0.40 mg (kg of fresh weight)(-1)] contained elevated Pb concentrations. The isotope ratios (Pb-207/Pb-206 and Pb-208/Pb-206) of total Pb were the highest in housedust (0.8587 +/- 0.0039 and 2.1049 +/- 0.0087) but lower than blood Pb ratios (0.8634 +/- 0.0027 and 2.1244 +/- 0.0061). When using bioaccessible Pb in housedust (0.8639 +/- 0.0018 and 2.1171 +/- 0.0036), the isotope ratios overlapped with blood Pb ratios, suggesting that incidental ingestion of housedust was the predominant contributor to children's blood Pb. Coupling the stable isotope technique with bioaccessible Pb is more reliable for identifying Pb exposure pathways than total Pb determinations.