HEAVY METAL ACCUMULATION BY SOME VEGETABLE CROPS GROWN ON SEWAGE-SLUDGE-AMENDED SOILS

Abstract

The use of sewage sludge on vegetable gardens is a public health concern. A growth chamber experiment was employed to investigate the effect of sewage sludge application on the copper, zinc, lead and cadmium content of lettuce, carrot and pea crops. No yield reduction or other toxicity symptoms were noted, although tissue levels of several metals were elevated. There were small increases in copper in the three vegetables, but zinc and cadmium increased considerably with sludge application. The higher Zn levels present no problem, but the higher Cd levels are undesirable. Cadmium uptake by vegetables and the increased dietary intake of Cd should be considered when sewage sludge is used on vegetable gardens.