ENVIRONMENTAL IMPACT EVALUATION FOR REUSING DRAINAGE WATER FOR SOME VEGETABLE CROPS PRODUCTION IN ARID LANDS

Abstract

The accumulation of heavy metals in farmland has become an important issue related to food security and environmental risk. The results of this study indicate heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) concentrations in soil and different vegetable crops associated with wastewater discharge of Abou-Rawash wastewater treatment plant, southern Giza governorate, Egypt. The results demonstrated the following:- - Generally, the concentrations of studied metals in wastewater samples were within the national and international recommended standards. - The concentrations of heavy metals in study soils were higher than their concentration in water samples. Soil samples were below the critical limits of heavy metals contamination except for Cd, Cu and Zn. - The trend of heavy metal accumulation in different parts of the studied crops followed the order Zn > Cu > Pb > Ni > Cr > Cd. - The general low capability of the plants to accumulate high quantities of metals in aerial parts of studied vegetables, yielded small translocation factors (TF) and bio concentration factors (BF). - Faba bean is not heavy metals accumulators although it showed a relatively high translocation factors (TF). - The transfer factor of study metals showed that Pb and Cr had the greatest potential of food chain entry followed by Cu, Zn, Ni and Cd. - Health risk assessments performed showed that normal consumption of vegetables assessed poses relatively low risk from heavy metal toxicities since daily intake rates and the hazard indices obtained were below the minimal risk levels.