Chemical Composition of Vegetables Grown on an Agricultural Soil Amended with Sewage Sludges

Abstract

AbstractHeavy metals were analyzed in edible and nonconsumable parts of radish (Raphanus sativus L. cv. White Icicle), carrots (Daucus carota cv. Chantenay), cabbage (Brassica oleracea var. capitata L. cv. Market Topper), green beans (Phaseolus vulgaris cv. Tenderette), sweet corn (Zea mays L. rugosa cv. Silver Queen), and tomatoes (Lycopersicon esculentum cv. West Virginia '63) grown on a sandy loam soil to which four sewage sludges were applied in the field at 90 and 180 Mg ha−1. Cadmium, Cr, and Pb concentrations in the edible parts of the vegetables from sludge treated plots were no more than 1.0 mg kg−1 above those from the untreated control plots. However, considerably more of these elements accumulated in radish tops, bean leaves, and corn leaves grown on a soil treated with two of the sludges. Nickel concentrations in vegetables from plots receiving two of the sludges were significantly higher than in the controls for both edible and nonconsumable parts of most of the vegetables grown. More Ni was absorbed by vegetables grown on a plot treated with sludge which was relatively low in total Ni (270 mg kg−1) than with a sludge which contained more than 47 times as much total Ni. Copper and Zn levels in vegetables grown on some sludge‐treated soils were elevated; however, these were not so high to cause alarm. The results emphasize the need for more information about sewage sludge than just total elemental analyses prior to application onto land on which vegetables will be grown.