Metal accumulation and its effects in relation to biochemical response of vegetables irrigated with metal contaminated water and wastewater

Agricultural application of metal contaminated water resulted in elevated concentrations of metals in irrigated soil and vegetables. Metal enrichment in irrigated soil is in the sequence of Cr > Fe > Pb > Mn > Zn > Cu > Cd. High metal translocation was observed from soil to plants with varied accumulation pattern in different species. Fe, Mn, Cu, Zn, Cr showed higher translocation to the aerial parts, while Cd, Pb exhibits their restricted mobility and concentrated in roots and stems. Hyperaccumulation of metals in vegetative parts resulted significant decrease (p < 0.05) in total chlorophyll and soluble sugars, with elevated (p < 0.05) protein and proline content in cultivated vegetables. Oxidative stress due to high metal concentrations significantly induced (p < 0.05) the antioxidant-enzyme activity. Peroxidase (52-206%) and catalase (40-106%) activity was noticeably higher in all the examined species, while enhanced activity of ascorbate peroxidase (70-78%) was observed in pea and spinach.