Bioavailability of Heavy Metals and Their Health Risk to Inhabitants through the Consumption of Vegetables around a Lead-Zinc Mining Plant in Nanjing, China

Contents of heavy metals in six vegetable species and the corresponding rhizospheric soils around a lead-zinc mining and smelting plant in Nanjing, China were investigated to assess the possible risks of heavy metal posed to human health through food chain and to discuss the relationships of heavy metals contents in vegetables and the corresponding rhizospheric soils. Compared to national sanitation standards for food and environmental quality standards for soil in China, both vegetables and rhizospheric soils were heavily contaminated by Cd, Zn and Pb. Enrichment coefficients of heavy metals differed greatly among vegetable species. CaCl₂-extractable metal contents were better than total metal contents in predicting the bioavailability of heavy metals. Health risk indices show that oral intake of Cd and Pb through vegetables poses a high health risk to local residents.