Influence of wastewater application and fertilizer use on the quality of irrigation water, soil and food crops: case studies from Northwestern India

摘要

This paper summarizes the available information on the pollution of groundwater and water bodies from anthropogenic sources in northwestern states of India leading to contamination of the soil-plant-animal-human foodchain, and possible mitigation options. Excessive applications of fertilizers to field and vegetable crops lead to nitrate and phosphate leaching and contamination of groundwater and water bodies. In certain situations, nitrates exceed the dangerous level of 10 mg N/L. Industrial effluents, released without any treatment to sewage drains, contain potentially toxic elements in concentrations that are several fold higher than those in domestic sewage water and exceed the maximum permissible limits for their disposal onto agricultural lands. The mean concentrations of Pb, Cr, Cd and Ni in sewage water were, respectively, 21, 133, 700, and 2200 times higher than those in tubewell water. The water of several shallow hand-pumps installed in vicinity of a sewage-water drain had several fold higher concentration of Pb, Cr, Cd and Ni than in deep tubewell water.