Dr T Esther Longkumer
CTO- Soil Science, KVK Phek, ICAR- NRCM, Porba
Soil pollution is the contamination of soil by human and natural activities which causes harmful effect on human being, plant and animal health. Soil pollution is caused by man-made chemicals such as agricultural runoff waters, industrial waste materials, acidic precipitates etc
Causes of Soil Pollution: The main causes of soil pollution are as under:-
• Seepage from a landfill
• Discharge of industrial waste into the soil
• Percolation of contaminated water into the soil
• Rupture of underground storage tanks
• Excess application of pesticides, herbicides or fertilizer
• Solid waste seepage
• Deforestation and Soil erosion
Types of Soil Pollution
Agricultural Soil Pollution: Plants on which we depend for food are under attack from insects, fungi, bacteria, viruses, rodents and other animals and compete with weeds for nutrients. Farmers use pesticides in order to kill unwanted populations and the remnants of such pesticides get adsorbed by the soil particles and contaminate root crops grown in that soil. The consumption of such crops causes the pesticides remnants to enter human biological systems, affecting them adversely. Agricultural effects are as follows:
• Reduced soil fertility
• Reduced nitrogen fixation
• Increased erodibility
• Deposition of silt in tanks and reservoirs
• Reduced crop yield
• Imbalance in soil fauna and flora
Industrial Soil Pollution: Large quantity of solid wastes like unused and rejected chemicals like sludge, press mud, saw dust, bottles, plastic materials and unwanted industrial wastes generated during manufacturing processes are dumped over on the surface of soil by almost all industries. The Industrial effects on soil are as under:
• Dangerous chemicals entering underground water
• Ecological imbalance
• Release of pollutant gases.
• Increased salinity.
• Reduced vegetation.
Soil Pollution due to Urbanization: Urban activities generate large quantities of city wastes including several biodegradable materials like vegetables, animal wastes, papers, wooden pieces, carcasses, plant twigs, leaves, cloth wastes as well as sweepings and many non-biodegradable materials such as plastic bags, plastic bottles, plastic wastes, glass bottles, glass pieces, stone/ cement pieces. If left uncollected and decomposed, they are a cause of several problems. Urbanization effects on soil are follows:
• Clogging of drains
• Inundation of areas
• Public health problems
• Pollution of drinking water sources
• Foul smell and release of gases
• Waste management problems
Remedial measures of soil pollution:
1. Soil erosion can be controlled by a variety of forestry and farm practices. Ex: Planting trees on barren slopes, Contour cultivation and strip cropping may be practiced instead of shifting cultivation. Terracing and building diversion channels may be undertaken. Reducing deforestation and substituting chemical manures by animal wastes also controls soil erosion in the long term.
2. Proper dumping of unwanted materials: Excess wastes by man and animals pose a disposal problem. Proper solid waste disposal should be followed.
3. Production of natural fertilizers: Bio-pesticides should be used in place of toxic chemical pesticides. Organic fertilizers should be used in place of synthesized chemical fertilizers. Ex: Organic wastes in animal dung may be used to prepare compost instead of throwing them wastefully and polluting the soil.
4. Proper hygienic condition: People should be trained regarding sanitary habits. Ex: Lavatories should be equipped with quick and effective disposal methods.
5. Public awareness: Public awareness programs should be imparted to educate people on health hazards through mass media, Educational institutions and voluntary agencies
6.Recycling and Reuse of wastes: To minimize soil pollution, the wastes such as paper, plastics, metals, glasses, organics, petroleum products and industrial effluents etc should be recycled and reused. Integrated waste treatment methods should be adopted like home composting.
7. Ban on Toxic chemicals: Ban should be imposed on chemicals and pesticides which are lethal to plants and animals. Nuclear explosions and improper disposal of radioactive wastes should also be banned.
Hence, recycling paper, plastics and other materials reduces the volume of refuse in landfills and reforestation helps prevent soil erosion and soil pollution.