File Name: soil pollution causes effects and control .zip
Pollution is the introduction of contaminants into the natural environment that cause adverse change.
- Land Pollution: Causes, Effects, and Prevention
- Soil Contamination: Its Causes, Effects, and Solutions
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- What Is Soil Pollution?
When many of us think of pollution, images of smoggy cities and litter-infested oceans come to mind.
Land Pollution: Causes, Effects, and Prevention
Environmental Risk Assessment of Soil Contamination. Environment pollution is a burning topic of the day. Air, water and soil are being polluted alike. Soil being a "universal sink" bears the greatest burden of environmental pollution.
It is getting polluted in a number of ways. There is urgency in controlling the soil pollution in order to preserve the soil fertility and increase the productivity. Pollution may be defined as an undesirable change in the physical, chemical and biological characteristics of air, water and soil which affect human life, lives of other useful living plants and animals, industrial progress, living conditions and cultural assets.
A pollutant is something which adversely interfere with health, comfort, property or environment of the people. Generally most pollutants are introduced in the environment by sewage, waste, accidental discharge or else they are by-products or residues from the production of something useful. Due to this our precious natural resources like air, water and soil are getting polluted. The basis of agriculture is Soil. All crops for human food and animal feed depend upon it.
We are losing this important natural resource by the accelerated erosion 10 some extent. In addition to this the enormous quantities of man-made waste products, sludge and other product" from new waste treatment plants even polluted water are also causing or leading to soil pollution.
In order to preserve the fertility and the productivity of the soil, control measures are to be taken in a herculean manner, thereby improving the health of all living beings.
Assessing the ecological risk of contaminated soil, pesticide application, sewage sludge amendment, and other human activities leading to exposure of the terrestrial environment to hazardous substances is a complicated task with numerous associated problems.
Not only is terrestrial ecological risk assessment a relatively new field of science that has developed rapidly only since the mids, but it is also complicated by the fact that soil, in contrast to most aquatic environments, is very often on private lands and traded as real estate.
Professional and economic divergence between the interests of scientists, stakeholders, authorities, engineers, managers, lawyers, nongovernment organizations NGOs and regulators is therefore not unusual. Even neglecting those aspects, a number of unresolved problems exist in the way we currently assess risk and manage the impact of anthropogenic substances in the terrestrial environment.
This chapter does not intend to present a comprehensive review of all published data from ecological studies at contaminated sites. Instead, the observations from all case studies are used in the discussion and form the basis for the final conclusion.
In each case, we try to answer the following questions:. Soil pollution is defined as the build-up in soils of persistent toxic compounds, chemicals, salts, radioactive materials, or disease causing agents, which have adverse effects on plant growth and animal health [ 1 ].
Soil is the thin layer of organic and inorganic materials that covers the Earth's rocky surface. The organic portion, which is derived from the decayed remains of plants and animal, is concentrated in the dark uppermost topsoil. The inorganic portion made up of rock fragments, was formed over thousands of years by physical and chemical weathering of bedrock. Productive soils are necessary for agriculture to supply the world with sufficient food [ 2 ].
Inorganic residues in industrial waste cause serious problems as regards their disposal. They contain metals which have high potential for toxicity. Industrial activity also emits large amounts of arsenic fluorides and sulphur dioxide SO 2 [ 3 ]. Fluorides are found in the atmosphere from superphosphate, phosphoric acid, aluminium, steel and ceramic industries. Sulphur dioxide emitted by factories and thermal plants may make soils very acidic.
These metals cause leaf injury and destroy vegetation. Copper, mercury, cadmium, lead, nickel, arsenic are the elements which can accumulate in the soil, if they get entry either through sewage, industrial waste or mine washings. Some of the fungicides containing copper and mercury also add to soil pollution. Smokes from automobiles contain lead which gets adsorbed by soil particles and is toxic to plants.
The toxicity can be minimized by building up soil organic matter, adding lime to soils and keeping the soil alkaline [ 4 ]. Organic wastes of various types cause pollution hazards. Domestic garbage, municipal sewage and industrial wastes when left in heaps or improperly disposed seriously affect health of human beings, plants and animals [ 5 - 7 ].
Organic wastes contain borates, phosphates, detergents in large amounts. If untreated they will affect the vegetative growth of plants. The main organic contaminants are phenols and coal. Asbestos, combustible materials, gases like methane, carbon dioxide, hydrogen sulphide, carbon monoxide, sulphur dioxide, petrol are also contaminants.
The radioactive materials like uranium, thorium, strontium etc. Fallout of strontium mostly remains on the soil and is concentrated in the sediments [ 8 ]. Decontamination procedures may include continuous cropping and use of chelate amendments. Other liquids wastes like sewage, sewage sludge, etc. Soil pollution is often caused by the uncontrolled disposal of sewage and other liquid wastes resulting from domestic uses of water, industrial wastes containing a variety of pollutants, agricultural effluents from animal husbandry and drainage of irrigation water and urban runoff [ 9 - 10 ].
Irrigation with sewage water causes profound changes in the irrigated soils. Amongst various changes that are brought about in the soil as an outlet of sewage irrigation include physical changes like leaching, changes in humus content, and porosity etc. Sewage sludges pollute the soil by accumulating the metals like lead, nickel, zinc, cadmium, etc. This may lead to the phytoxicity of plants.
Heavy metals are elements having a density greater than five in their elemental form. They mostly find specific absorption sites in the soil where they are retained very strongly either on the inorganic or organic colloids. They are widely distributed in the environment, soils, plants, animals and in their tissues. These are essential for plants and animals in trace amounts.
Mainly urban and industrial aerosols, combustion of fuels, liquid and solid from animals and human beings, mining wastes, industrial and agricultural chemicals etc. Heavy metals are present in all uncontaminated soils as the result of weathering from their parent materials.
Concentration of heavy metals in soils and plants is given in Table 1. In agricultural soils, however, the concentration of one or more of these elements may be significantly increased in several ways, like through applications of chemicals, sewage sludge, farm slurries, etc. Increased doses of fertilizers, pesticides or agricultural chemicals, over a period, add heavy metals to soils which may contaminate them. Certain phosphatic fertilizers frequently contain trace amounts of cadmium which may accumulate in these soils.
Likewise, some fertilizers when applied to soils, they add certain heavy metals which are given in Table 2. The range of heavy metal contents in sludges is given in Table 3. The fate of heavy metals in soil will be controlled by physical and biological processes acting within the soil.
Metal ions enter the soil solution from these various forms of combination in different rates they may either remain in solution or pass into the drainage water or be taken up by plants growing on the soil or be retained by the soil in sparingly soluble or insoluble forms. The organic matter of these soil have great affinity to heavy metals cations which form stable complexes thereby leading to reduced nutrient content [ 11 - 12 ].
Pesticides are quite frequently used to -control several types of pests now-a-days. Pesticides may exert harmful effects to micro-organisms, as a result of which plant growth may be affected. Pesticides which are not rapidly decomposed may create such problems.
Accumulation is residues of pesticides in higher concentrations are toxic. Pesticides persistence in soil and movement into water streams may also lead to their entry into foods and create health hazards. Pesticides particularly aromatic organic compounds are not degraded rapidly and therefore, have a long persistence time which can be seen in Table 4.
Mercury, cadmium and arsenic are common constituents of pesticides and all these heavy metals are toxic. At present DDT and a number of organochlorine compounds used as pesticides have been declared harmful and banned in U. It is due to the persistence of their residues in soils for considerable time without losing their toxicity. This has led to higher concentration of these pesticides in vegetation, in animal flesh and milk.
Eventually man has been affected. In view of their demerits, organochlorines have been replaced by organophosphate pesticides which are more toxic, but do not leave any residue. They do not pollute the soil. The rodenticides too add to soil pollution. A major method of checking this pesticidal pollution is to increase the organic matter content of the sol and choose such pesticides which are non-persistent and leave no harmful residue.
The sources which pollute the soil are twofold: Agricultural sources and non-agricultural sources. Figure 1 shows the different sources for the soil pollution. Soil pollution comes from different sources including agriculture and animal husbandry. Some of the agricultural practices lead to soil pollution.
They are animal wastes, use of long lived pesticides, herbicides, fungicides, nematocides, etc. Soil pollution by non-agricultural sources is usually the direct result of urban sprawl caused by rapidly increasing population and a rapidly per capita output of waste related to our modem way of life.
Its materials that find their entry into the soil system have long persistence and accumulate in toxic concentration and thus become sources of pollution. Some of those most important soil pollutants are inorganic toxic compounds. Soil pollution is caused by the presence of man-made chemicals or other alteration in the natural soil environment.
This type of contamination typically arises from the rupture of underground storage links, application of pesticides, and percolation of contaminated surface water to subsurface strata, oil and fuel dumping, leaching of wastes from landfills or direct discharge of industrial wastes to the soil. The most common chemicals involved are petroleum hydrocarbons, solvents, pesticides, lead and other heavy metals.
This occurrence of this phenomenon is correlated with the degree of industrialization and intensities of chemical usage. A soil pollutant is any factor which deteriorates the quality, texture and mineral content of the soil or which disturbs the biological balance of the organisms in the soil. Pollution in soil has adverse effect on plant growth. Oxygen from air and water but other necessary nutrients like nitrogen, phosphorus, potassium, calcium, magnesium, sulfur and more must be obtained from the soil.
Farmers generally use fertilizers to correct soil deficiencies. Fertilizers contaminate the soil with impurities, which come from the raw materials used for their manufacture.
Soil Contamination: Its Causes, Effects, and Solutions
We tend to look skywards when talking about pollution, but this problem is not confined to our skies. The soil in which our fruit and vegetables grow is also suffering its consequences, the effects of which getting to us directly, for instance, through the aforementioned foodstuffs. The time has come to look after what lies under our feet! Soil pollution is mostly caused by chemical substances produced by human activity. The soil is the skin of the earth, a mantle full of scars, thousand-year-old wrinkles and more recent injuries caused both by man and nature itself. Some of these ulcers are incurable — such as the extinction of species —, whereas others jeopardise health and food security, all of which threaten the well-being of the world's 3. This invisible affliction appears when the concentration of pollutants on the surface becomes so high that it harms land biodiversity and endangers health, particularly through food.
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. 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. These compounds are mainly formed through soil microbial activity and decomposition of organisms e. 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.
Effect: These pollutants affect and alter the chemical and biological properties of soil. As a result, hazardous chemicals can enter into human food chain from the.
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Soil contamination refers to the destruction of land that could be used constructively by human activities, either directly or indirectly. Presently, , ha of UK land is thought to be contaminated by toxic elements such as lead and arsenic. The same goes for the other industrialized nations which are the worst hit. The developing countries are also steadily but surely moving toward this direction.
Environmental Risk Assessment of Soil Contamination. Environment pollution is a burning topic of the day. Air, water and soil are being polluted alike. Soil being a "universal sink" bears the greatest burden of environmental pollution. It is getting polluted in a number of ways.
This includes chemical, physical and biological processes affecting flora, fauna, water, air and soil in relation to environmental pollution.
What Is Soil Pollution?
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