The problem of soil pollution is rapidly increasing in the rural, urban and industrial areas due to unscientific and irrational disposal of solid wastes generated by human beings from their domestic and industrial activities. In many rural parts of our country, daily thousands of people pollute the soil through their wastes, as toilet facilities are not available. In industrial areas heavy metals, plastics and other persistent organic compounds including msticides, are the major causes of soil pollution. Hazardous wastes in soil, often accummulate in the bodies of organisms including man, because they are not excreted. Once they enter the food chain, they become more concentrated at each level. Note in Fig. how DDT, a pes'ticide, becomes more concentrated as it passes along fmm producer to consumers. The story of DDT is one everybody should know. It was once a widely used pesticide. It is a substance that does not easily break down. It can persist in the environment for as long as fifteen years. It enters birds through the organisms they feed on which in turn get it from the organisms lower in the food chain. When a high concentration builds up in birds. their reproductive systems are affected. As a result they lay fragile eggs that easily break in the nests. Similarly other pesticides are also major soil pollutants, because of their retention in soil. The pesticides not only kill the targeted pests, but also kill many harmless and even beneficial insects. They cause more harm than benefit. Therefore, DDT and many such agrochemicals have been banned in many parts of the world.
What should be done to minimise soil pollution? First of all, in India, the use of open fields and banks of ponds and tanks as open toilets should be stopped, by providing latrines. Care should be taken while dumping wastes in the soil. Substances such as heavy metals, plastics and other substances that remain unchanged for very long time should not be added to the soil. Instead ways should be found for their reutilisation by various recycling processes. Utmost care should be taken so that the minimum necessary pesticides or other agrochemicals are used. In fact. biological control of pests and fixation of nitmgen should be urgently developed by rcsearch, so that dependence on widespread use of toxic chemicals is reduced.