This article throws light upon the six adverse effects of soil pollutants. The adverse effects are: 1. Effects of Industrial Pollutants 2. Effects of Urban Waste Products 3. Effects of Radioactive Pollutants 4. Effects of Pesticides 5. Effects of Biological Agents 6. Effects of Soil Sediments.
Adverse Effect of Soil Pollutant # 1. Effects of Industrial Pollutants:
1. Industrial effluents when discharged through sewage system poison the biological purification mechanism of sewage treatment causing several soil and water borne diseases.
2. Some of the trade wastes contain pathogenic bacteria. For example, pathogen Anthrax bacilli is present in tannery wastes.
Adverse Effect of Soil Pollutant # 2. Effects of Urban Waste Products:
1. Solid wastes cause offensive odour and clogging of ground water filters. Suspended matter in sewage can blanket the soil, thereby interfering with the soil moisture.
2. An estimate indicates that volume of waste water from industrial complexes added to soil will be comparable to that of domestic sewage by 2012 A.D. In India agricultural discharge, which carry fertilizing ingredients and biocides etc. are expected to be three times than domestic sewage.
Moreover, thermal pollutants generated by discharges from thermal power plants will be highest in volume by 2015 A.D. Today developed countries are fighting against thermal and chemical pollutants, while Indians have to combat both chemicals and pathogens with their limited resources.
Adverse Effect of Soil Pollutant # 3. Effects of Radioactive Pollutants:
1. The problem of radioactive wastes dumped into the soil is more complicated. This is so because every radioactive element like radium, uranium, thorium and plutonium etc. can remain active in soil for thousands of years. Since the radioactive wastes are produced in tremendous quantities and have a high activation energy, they create an extremely difficult public health problem.
2. Radioactive pollutants can produce great human misery. When food containing radionuclides is taken by man, some of them concentrate in specific body organs where they cause a number of undesirable diseases of digestive tract. Even the thyroid gland is damaged due to accumulation of iodine. Cs-137 is taken by body in place of potassium.
Adverse Effect of Soil Pollutant # 4. Effects of Pesticides:
Modern agriculture rely heavily on pesticides. Although these chemicals enhance vegetation but they disrupt the natural ecosystem.
1. Pesticides not only pose a potential hazard to man, animal, fish and livestock but they severely affect the desired yield of crop and soil. Even the accepted dose of pesticides create deleterious effects on soil fertility. According to a report Death in the Grab of Pesticides, pesticides spread most alarmingly in the environment through migration.
They are washed off from the crops into water, enter water bodies, penetrate with fodder, animals and hence food stuffs. In India, 35000 to 40000 tonnes of hazardous chemicals are sprayed on the agricultural crops each year.
2. Pesticides retained in soil concentrate in crops, vegetables, cereals and fruits which taint them to such an extent that they are not useable.
3. Persons who used vegetables contaminated with 0.5 g or more PCBs developed darkened skin, eye damage and severe acne. DDT accumulates in the food chain. It is continuously recycled in living systems.
4. Pesticides like DDT, endrin, dieldrin, heptachlor etc. are known to seep gradually through soil into ground water and eventually contaminate public drinking water supplies.
5. Their excessive use has also resulted in defoliation of forests adversely affecting flora and fauna.
6. Organophosphate pesticides cause extreme muscular weakness, tremors and dizziness in poisoned animals.
7. Many hunting birds feeding on grains, particularly contaminated with high level of DDT, are threatened with extinction.
8. People in contact with pesticides, such as, farmers, farm workers and agriculturists are much more prone to be poisoned by them. Their excessive absorption leads to greater accumulation of acetylcholine in the body. Chronic absorption damages liver, kidney causing malfunctioning, excess of amino acid in urine and blood abnormalities.
Adverse Effect of Soil Pollutant # 5. Effects of Biological Agents:
Soil supports distinctive flora and fauna, such as, bacteria, algae, fungi, protozoa, rotifers, nematodes, earth worms, actinomycetes and several pests which make the biological system of soil complex. Some organisms also help in maintenance of soil fertility while majority of the micro-organisms act as chronic pollutants.
Soil has been a potential carrier of microbial growth, non-biodegradable matters and pathogens which can endanger human health and life.
1. Pathogenic soil bacteria are chronic disease carrier which are transmitted from man to soil or vice versa causing cholera, typhoid, bacillary dysentery, paratyphoid fever etc.
2. Geohelminthes are reported to suck vitamins and proteins from the intestinal nutrients of the host. Such absorption of essential nutritional constituents results in severe malnutrition.
3. Fungi and actinomycetes—the saprophytes normally develop in soil or vegetation. They cause most serious subcutaneous and systemic mycoses.
4. Some bacteria and fungi in soil secrete growth hormones that affect root growth. Antibiosis microbes in soil produce antagonistic effect through metabolic products which may inhibit the growth of symbiotic bacteria.
Adverse Effect of Soil Pollutant # 6. Effects of Soil Sediments:
1. Suspended sediment is usually eroded top soil and is the most fertile portion of the soil. Eroded soil is deteriorated and the carried top soil could deposit in places where fertility is a liability.
2. Water reservoirs can be filled by sediments and decrease their storage capacity. Tarbela Dam Reservoir in Pak, world’s largest, has a silt load of about 16 times larger than predicted by dam’s engineers.
3. In India, Kosi canal has been so heavily silted in its 20 years existence (because of over grazing its water shed) that it now provides water to only few irrigation areas. It has reduced from 570,000 hectare to 81,000 hectare.
4. Sediments adversely affect the physical and chemical compositions of water. It carries numerous ions (e.g., Na+, K+, NO–3, CI–, SO2-4 and PO3-4) from the agricultural fields contaminated with pesticides.
5. Sediment causes eutrophication in the whole stretch of water bodies affecting severely aquatic life.
6. Suspended sediments make water unfit for municipal water supplies and for industrial purposes.
7. Excessive suspended load of clay and silt in the river water damages turbines which are used to generate hydroelectricity.