Impact of Sewage Water on Vegetable Crops and Soils of Bihar

Abstract

The study of present investigations revealed there is an accumulation of micronutrients and heavy metals in soils with maximum accumulation at the point of discharge. Continuous disposal of sewage-sludge, containing domestic and industrial effluents on agricultural land is a major source of plant nutrients, but it also contains a sufficient amount of non-essential and heavy metals causing soil pollution. Transfer of metals from added sewage sludge to the soils and subsequently uptake by the plants that enter the feed and food-chain which pose hazardous for human health and animals. Moreover, it is pointed out that continued monitoring or treatment of sewage water before disposal into the land or integrated water management are some of the suitable measures for effective utilization of poor quality water in sustainable agricultural production. The concentration of heavy metals like Ni, Cr, Cd and Pb in sewage sludge treated soils at nearby and distant sites from discharge point at Patna bye-pass were investigated. The study revealed that the sites nearest to discharge point contained appreciably higher concentration of these metal cations in comparison to the sites away from the discharge point of the sewage water. Plants growing on such soils accumulate excesses amount of micronutrients and heavy metals in their tissues which may enter in the system of animal and human being. Accumulation of trace metal cations in different plant species differed widely which varied from crop to crop and place to place. The relative accumulation of these metals in different plant species was noticed that leafy vegetables, viz. poi and red spinach (Amaranthus) accumulated most of trace metal cations to the greater extent in comparison to other crops. However, toxic concentration of these trace metal cations in plants and soils should be the matter of concern and indicate the need for continuous monitoring or treatment of sewage water before it is laid down into the field. Though the study during the investigations confirm that sewage water (domestic & urban origin) can certainly and effectively increase water resource for irrigation but there is need for regular monitoring of the concentrations of trace metal cations and potentially toxic elements in soils as well as in plants.