Assessment of heavy metal accumulation and performance Of some physiological parameters in zea mays l. And Vic1a faba l. Grown on soil amended by sewage Sludge resulting from sewage water Treatment in the state of qatar

Abstract

Pot experiment was conducted to explore extent of concerns regarding agricultural use of sewage sludge for crop production in the state of Qatar. Extent of heavy metal accumulation and its subsequent impact on physiological performance in Zea mays and Viciafaba plants grown on sludge - amended soils was explored. Analysis revealed that all tested heavy metals were several times higher in pure sludge compared to pure garden soil. Plants grown in sludge -mixed soil accumulated large amounts of all the tested heavy metals, except Mn. Tissue content of all metals exhibited continuous increase as the ratio of sludge in soil mixtures increased. Compared to other metals, Zn and Cd were strongly accumulated. Magnitude of accumulation was greater in Vicia faba than in 7,ea mays. Growth, in response to sludge treatment, was slightly promoted in 7,ea mays and strongly reduced in Viciafaba. Toxicity or deficiency symptoms were noticed only on Vicia faba. Nodulation in Vicia faba was inhibited by sludge treatment. Chlorophyll synthesis was slightly promoted in Zea mays and retarded in Viciafaba plants in response to growth on sludge mixed soil. Nitrate reductasc activity and content of total soluble proteins in leaves, was generally, promoted in Zea mays and reduced in Vicia faba. PEP carboxylase activity in 7,ea mays and in Vicia faba was reduced. Results, generally, indicate that physiological performance was better in Z,ca mays than in Vicia faba. Results are discussed from the point of view of practicality of using sewage sludge in agriculture in the State of Qatar.