Revegetation in Arid Zones: Environmental Impact of Treated Wastewater Irrigation in Al-Karak Province, Jordan

摘要

This study was conducted in an arid area in southern Jordan to investigate the appropriatencss of using treated wastewater for the cultivation of salt-tolerant fodder cover plants (i.e. Tamarix sativa, Medicago sati-va, Pennisetum glaucum, and Atriplex hallimus) in Al-Lajoun Valley and its environmental impact in terms of heavy metal concentrations like copper, lead, chromium, and cadmium in soils and leaves in the context of arid land revegetation. Although the treated wastewater contains higher concentrations of Cu, Pb, Cr, and Cd than the Jordanian recommended maximum concentration of metals in irrigation water, the results showed no accumulation of heavy metals in irrigated soils and plants. Concentrations of metals in wastewater-irrigated soils were much lower than the critical soil total concentration. In addition, heavy metal concentrations in leaves of the grown cover plants were within the normal range in plants, which is advantageous if such plants are to be used as fodder for animals. Pollution load index and plant concentration factor varied with the grown cover plants. High transfer values of Cu, Pb, and Cr from soil to particularly P. glaucum were observed. An inverse relationship between transfer factor and total metal concentrations also was observed. In conclusion, treated wastewater can be used, at least in the short term, as a practical solution for irrigation water shortage to minimize soil degradation and for revegetation purposes.