Trace Element Concentrations of Sewage Treatment Plant Effluents and Sludges; Their Interactions with Soils and Uptake by Plants

Abstract

AbstractMetropolitan sewage sludges and effluents were characterized in relation to their total and water extractable trace elements, their reactions with soils, and their effects on plants. The total concentrations of trace elements in sludges and effluents were highly variable depending on the source and were often much higher than concentrations found in soils. Concentrations of Cu, Zn, Ni, Co, and Cd were consistently greater in the saturation extracts obtained from sludges than those obtained from a large sampling of California soils. The effects of irrigating bean, barley, and tomato plants in a greenhouse sand culture experiment with diluted saturation extracts of sludges from different sources were all adverse but variable depending on the sludge source. Leaf samples from treated plants frequently contained toxic levels of B and excessive levels of one or more of the following elements: Cu, Mo, Ni, Co, Pb, and Cd.