Chemical properties and toxicity of soils contamined by application of wastwater sludge of high heavy metals content

Abstract

Heavy metal (HM) contamination of agricultural soils is a worldwide ecological problem. Wastewater sludges (WWS) produced from communal wastewater treatment plants is commonly recognized as a significant basis of nutrient and soil conditioner for cultivating use. Determination of intensities of HMs in WWS is essential prior to application of the sludge to agriculture for of the intrinsic risk of HM toxicity to soil. Wastewater sludge created from different WW sources were analysed for a range of total HMs using ICP-AES. Most of the samples analysed show agreement with respect to the regulatory parameters established by the USEPA, South Africa and EU guidelines for levels of HMs in WWS envisioned for agricultural soil application. In this study, the concentrations of HMs (Cd, Cu, Ni, Pb, and Zn) were investigated in the agricultural soils before and after WWS applications.