Pesticide and heavy metals residue in wastewater, soil and plants in wastewater disposal site near Al-Lajoun valley, Karak/Jordan

Disposal of raw wastewater and sludge creates the potential for pesticides and heavy metal contamination. A field study was conducted to determine the residue concentration level of chlorinated pesticides and four heavy metals (Zn, Pb, Cu and Ni) in raw wastewater, soils and plants at Karak raw wastewater disposal site. The results indicated that the investigated area was heavily contaminated with various types of pesticides. The distribution of different pesticides in soils and wastewater was influenced by the solubility of these pesticides such that the higher the solubility the more is present in water phase and vice versa. Vinclozoline was the dominant pesticide in most of the samples. Some pesticides of which application is restricted to be used in Jordan, such as DDT and its metabolites, were detected in the investigated area. Heavy metals existed in relatively higher concentrations in soils than in wastewater, which was due to the high pH of the wastewater enhancing its precipitation. Zinc was the highest among the analyzed heavy metals in both wastewater and soils. The residue level of both heavy metals and chlorinated pesticides were highest at the emission source decreasing gradually with distance.