Soil pollution is the presence of toxic chemicals pollutants or contaminants in soil, in an amount high enough concentration to pose a risk to human health and/or the ecosystem. In the case of contaminants, which occur naturally in soil, even when their levels are not high enough to pose a risk, soil pollution is still said to occur if the levels of the contaminants in soil exceed the levels that should naturally be present.
Soil acts as a natural sink for contaminants, by accumulating and sometimes concentrating contaminants which end up in soil from various sources. Tiny amounts of contaminants accumulate in the soil and – depending on the environmental conditions (including soil types) and the degradability of the released contaminant – can reach high levels and pollute the soil. If the soil is contaminated, home-grown vegetables and fruits may become polluted too. This happens because most of the soil pollutants present in the soil are extracted by the plants along with water every time they feed.
All soils, whether polluted or unpolluted, contain a variety of compounds (contaminants) which are naturally present. Such contaminants include metals, inorganic ions and salts (e.g. phosphates, carbonates, sulfates, nitrates), and many organic compounds (such as lipids, proteins, DNA, fatty acids, hydrocarbons, PAHs, alcohols, etc.). These compounds are mainly formed through soil microbial activity and decomposition of organisms (e.g., plants and animals). Additionally, various compounds get into the soil from the atmosphere, for instance with precipitation water, as well as by wind activity or other types of soil disturbances, and from surface water bodies and shallow groundwater flowing through the soil. When the amounts of soil contaminants exceed natural levels (what is naturally present in various soils), pollution is generated. There are two main causes through which soil pollution is generated: anthropogenic (man-made) causes and natural causes.
Soil Pollution Causes
There are numerous causes of soil pollution that occur every day or even every minute.
Man-made soil pollution originates in several types of processes, some deliberate and some accidental. Human-caused soil pollution can work in conjunction with natural processes to increase the toxic contamination levels in the soil.
Accidental spills and leaks during storage, transport or use of chemicals (e.g. leaks and spills of gasoline and diesel at gas stations, several of which goes unreported in Indian Urban warehouses
Foundry activities and manufacturing processes that involve furnaces or other processes resulting in the possible dispersion of contaminants in the environment;
Mining activities involving the crushing and processing of raw materials, for instance, heavy metals, emitting toxic substances; by creation of derelict land in Jharia, Raniganj and other coal mines.
Construction activities through construction dust may easily spread around through the air and is especially dangerous because of its lower particle size (less than 10 microns). Such construction dust that gets generated around NCR, Delhi can trigger respiratory illnesses such as asthma and bronchitis, and even cancer. Moreover, the sites that involve the demolition of older buildings can release asbestos, a toxic mineral that can act as a poison in soil. Asbestos particles can be redistributed by the wind. Construction sites are the most important triggers of soil pollution in urban areas, due to their almost ubiquitous nature. Almost any chemical substance handled at construction sites may pollute the soil.
Agricultural activities involving the diffusion of herbicides, pesticides and/or insecticides and fertilizers as in the fields of Punjab, Haryana, Western UP. Moreover, the soil of the crops is polluted to a large extent with pesticides, fertilizers, herbicides, slurry, debris, and manure.
Transportation activities, releasing toxic vehicle emissions
Chemical waste dumping, whether accidental or deliberate – such as illegal dumping that takes place in the vicinity of urban araes of Delhi, Gurugram
Urban waste consists of garbage and rubbish materials, dried sludge and sewage from domestic and commercial waste. Moreover the storage of waste in landfills, as the waste products may leak into groundwater or generate polluted vapors, such as what is happening in Deonar hills, Mumbai and Ghaziabad
Thus the Soil Contaminants include
Lead (Pb) from sources like- lead paint, mining, foundry activities, vehicle exhaust, construction activities, agriculture activities
Mercury (Hg) from sources like mining, incineration of coal, alkali and metal processing, medical waste,
Arsenic (As) from mining, coal-fired power plants, lumber facilities, electronics industry, foundry activities, agriculture, natural accumulation
Copper (Cu) from mining, foundry activities; construction activities
The Effects of Soil Pollution
Soil pollution affects plants, animals and humans alike. While anyone is susceptible to soil pollution, soil pollution effects may vary based on age, general health status and other factors, such as the type of pollutant or contaminant inhaled or ingested. However, children are usually more susceptible to exposure to contaminants, because they come in close contact with the soil by playing in the ground; combined with lower thresholds for disease, this triggers higher risks than for adults. Therefore, it is always important to test the soil before allowing your kids to play there, especially if you live in a highly industrialized area.
Diseases Caused by Soil Pollution
Humans can be affected by soil pollution through the inhalation of gases emitted from soils moving upward, or through the inhalation of matter that is disturbed and transported by the wind because of the various human activities on the ground. Soil pollution may cause a variety of health problems, starting with headaches, nausea, fatigue, skin rash, eye irritation and potentially resulting in more serious conditions like neuromuscular blockage, kidney and liver damage and various forms of cancer.
CONTROL OF SOIL POLLUTION
Soil pollution can be controlled in many ways. There can be many preventive ways
Go organic: Organic agriculture uses much fewer chemical fertilizers and pesticides, preventing chemicals from seeping into the soil.
Proper farming methods: Finding alternatives to chemical fertilizers and pesticides is an ideal way to avoid soil erosion. Rotational and mixed farming are also encouraged.
Dispose of household waste responsibly: Recycling waste and not dumping it in landfill will keep the soil free of pollution. Not throw in batteries and electrical items into household waste bins will help to keep the soil free of dangerous chemicals.
Prevent or Manage industrial waste: Properly managing industrial and domestic waste can help prevent soil erosion. Solid waste treatment is also a good preventive measure. Regular health and safety checks and adequate waste disposal methods will ensure that industrial chemicals and other waste are not allowed to contaminate our precious soil.
Community Awareness: Creating awareness about the effects of soil pollution can help prevent its occurrence.
Burn fewer fossil fuels: Cleaner air makes it easier for us to have cleaner soil. Fresh, pure rain will keep the soil free of pollutants.