Projections of long-term human multimedia exposure to metal(loid)s and the health risks derived from atmospheric deposition: A case study in the Pearl River Delta region, South China

This is one of a limited number of studies that investigates multimedia exposure to metal(loid)s and the related human health risks caused by atmospheric deposition in China and Asia. The aggregate multimedia human exposure included the accidental ingestion and dermal adsorption of soil and surface water, as well as the intake of grains, fruits, vegetables, meats and eggs, milk and dairy products, and freshwater fish. The values and variabilities of atmospheric deposition and exposure factors were identified as two major uncertainty sources. The annual variations in wet and bulk deposition were propagated from the variabilities of particulate matter (PM) xprecipitation and the linear regressed coefficients of flux similar to PM x precipitation, and the annual variation in dry deposition was propagated by subtracting the wet deposition from the bulk deposition. The variabilities in the exposure factors were updated based on the latest published regional data. Long-term atmospheric deposition was identified as a vital source of Cd contamination in surface soil and freshwater bodies and As accumulation in freshwater fish. The noncarcinogenic (NC) risk probabilities caused by Cd were the highest, followed by As. The overall uncertainties related to the NC risk probabilities were much lower for both adults and 6- to 17-year-old children/adolescents, while those related to the carcinogenic risk (CR) probabilities were much lower for 2- to 5-year-old children and 6- to 17-year-old children/adolescents. Our results could help infer the cobenefits due to the current regional air pollution control policy.