Lead/cadmium contamination and lead isotopic ratios in vegetables grown in peri-urban and mining/smelting contaminated sites in Nanjing, China

Lead/cadmium contamination in vegetables grown in peri-urban area of Nanjing, China was assessed and the route for metals entering into plants was investigated through lead isotopic tracing. Results show that agricultural soils have been polluted with Cd. Contents of Pb (22.1-37.5 mg kg ^-1dw) and Cd (2.53-4.19 mg kg ^-1 dw) in vegetables' edible parts nearby a lead/zinc mining/smelting plant were beyond their maximum allowable limit prescribed in the (EC) No 1881/2006. Pb isotope ratios in plants differed from those in the corresponding soils, suggesting that soils were not the only contamination source of Pb and Cd in plants.