HEAVY METALS IN VEGETABLES IRRIGATED WITH WASTEWATERS IN GAZIANTEP, TURKEY: A REVIEW OF CAUSES AND POTENTIAL FOR HUMAN HEALTH RISKS

摘要

Irrigating crops with municipal and industrial waste-waters may lead to elevated concentrations of heavy metals in both soil and agricultural products which, in turn, pose human health risk concerns. Using wastewater as an irrigation resource is common in many countries, including Turkey, which has one of the lowest per capita waste-water treatment plant rates in the world. Although total concentrations of certain contaminants in wastewater are sometimes monitored, there is a significant lack of robust concentration and chemical speciation data from both irrigated soil and the crops themselves. This information is vital to better understanding the risks posed to human health in Turkey through the use of wastewater for irrigation. Gaziantep, in south central Turkey, attracts a large number of immigrants from surrounding cities and the East Anatolia Region. Irrigation with municipal and industrial wastewater in the Gaziantep area affects approximately 150,000 acres of agricultural land, much of which is used to meet local demand for fruits and vegetables. Because analytical data indicate that both field soils and plants grown in those soils have metal concentrations that are in excess of recommended maximum tolerable levels proposed by FAO/WHO, WHO/EU and Turkish Regulations, risks from food consumption may be elevated. Further research is needed to better understand the degree of metal bioaccumu-lation, ion speciation, and the impacts to human health associated with crops from wastewater-irrigated soils.