ABSTRACT
Heavy metal accumulation in farming soil depends mainly on the heavy metal concentration in fertilizers or amendments and the application rate of each. Use of municipal sewage sludge as soil amendment is of current interest because of environmental and economic concerns. Application of sludges, as sources of plant nutrients, to soil at rates consistent with the nutrient requirements of a crop are believed to be most beneficial. It has been observed that sludge application reduces the surface runoff and gives some protection against soil erosion [1]. The composition of sewage sludge varies greatly depending on the source of sewage (domestic, industrial, etc.) [2]. The undesirable consequence of sludge application arises from the heavy metal content of the sludge, which may be taken up by the plants [3] and will have indirect impacts on animal health, human health, and/or the environment.
