Abstract

Consumption of food crops contaminated with heavy metals is a major food chain route for human exposure. In the present study, vegetables grown in the sewage and tube well water irrigation are Raphanus sativus, Daucus carrota and Brassica rapa. Concentration of Cd, Pb and Ni was significantly higher in sewage irrigated soil at all the four depths (0-15, 15-30, 30-45 and 45-60 cm), respectively. Cadmium, Lead and Nickel concentration are higher at the surface horizons and it decreases sharply with depth in both tube well and sewage irrigated soils. Extent of heavy metal built up in sewage irrigated soils was significant in both 0-15 and 15-30 cm depth. Higher concentration of Pb, Cd and Ni, were observed in the roots of all crops grown in sewage irrigated soils compared to that of crops grown on tube well irrigated soils. Sewage water irrigation has a great potential to contaminate the soil which may lead to the accumulation of heavy metals in crop plants and may cause harmful effect on animals and plants. Results, indicate that, long term and indiscriminate application of sewage water, which contains heavy metals may cause accumulation of heavy metals in surface and sub-surface soils and the buildup of heavy metals on soil profile may prove harmful not only to plants, but also to consumers of the harvested crops.

Key words: Crops, heavy metals, water, sewage, tube well.