Sewage water irrigation and heavy metals

Abstract

The use of industrial or municipal waste water in agriculture is a common practice in almost all the parts of the world. Changing scenario with economic development of the society towards large scale urbanization, increasing population and industrialization is leading to production of huge quantities of effluents in India. Industrial and domestic effluents are either used or disposed off on land for irrigation purposes that create both opportunities and problems. The sewage effluents from municipal origin provide a reliable source of water supply to the farmers and adding appreciable amounts of major and micronutrients and organic matter to the soils. Treatment of waste water usually produces effluents of suitable quality that can be used for irrigation purposes with minimum impacts on human health or environment, but this also contains variable amounts of heavy metals, which may limit the long term use of effluents for agricultural purposes. Transfer of these metal cations to the soil and subsequently to the plants that enter the feed and food chain, pose significant health concerns which is a matter that needs proper attention. Waste water irrigation may have significant contribution towards solving the problem of water shortage to some extent and safe disposal of sewage water to a larger extent. Hence most of the farmers, especially in urban areas, use sewage water because it is available free of cost and act as an effective fertilizer. However, its harmful effects on quality of produce which need to be studied for taking safety measures. The information generated by the team of scientists of AICRP on Ground Water Utilization, on soil pollution due to heavy metal accumulation, is quite useful for taking precautionary measures in advance especially in those area where sewage sludge is being disposed off and used by the farmers as organic manures. This bulletin embodies the useful information generated by the scientists on trace & heavy metal accumulation in soils and varieties of vegetable and field crops. Though the study confirms that the sewage water can effectively increase water resources for irrigation but there is need for continuous monitoring of the concentration of these metal cations in soils and plants. I congratulate and appreciate the scientists for their efforts in the preparation of this bulletin entitled `Sewage Water Irrigation and Heavy Metal Accumulation in Patna by-pass Area' and hope that this will be useful to the researchers, scientists, students, planners, environmentalists and farmers in sustainable use of waste waters for augmenting the agricultural production of the state.