Chemical and Bioavailability of Lead, Zinc, Cadmium and Copper In Radish, Carrot, Spinach and Lettuce Grown In a Smelter Contaminated Soil.

The town of Spelter, WV is adjacent to a waste pile from a zinc smelting plant. Material from the pile has contaminated nearby residential soils with lead, zinc, cadmium and copper and there are concerns about the safety of food products grown on these soils. Four common garden species radish (Rapahanus sativus L.) var. Cherry Belle, carrot (Daucus carota L.) var. Sugarsnax, spinach (Spinacia oleracea L.) var. Corvair and lettuce (Lactuca sativa L.) var. Iceberg. Metal concentrations in roots, stems and leaves were compared to results from a multi-step sequential extraction. Edible tissue concentrations and publicly available consumption data were compared to World Health Organization human consumption regulatory criteria. The largest concentrations of each metal were Pb (125 mg kg^-1) and Zn (1500 mg kg^-1) in radish roots, Cd in carrot roots (40 mg kg^-1) and Cu in radish roots and carrot stems (25 mg kg^-1). The combined soluble and exchangeable fractions for Zn and Cd were similar to the whole plant tissue concentrations for each species. However, to account for Pb and Cu uptake, concentrations in the more recalcitrant fractions (weak acid soluble, reducible and oxidizable) had to be included. Uptake of Cd by carrot roots was 5 times larger than the regulatory limits for men, 8 times larger for women and 12 times larger for children. Uptake of Zn in carrots and lettuce was also above the regulatory limit for women and children. Cadmium concentrations in spinach did not exceed consumption thresholds except for children, perhaps because the high background Zn concentrations interfered with Cd uptake.