Soil pollution

Soil pollution

Intended Learning Outcomes

At the end of this session, students will be able to

• Explain soil Pollution

• Describe the factors effecting soil pollution

• Discuss the effect of soil pollution

• Discuss control of soil pollution

Content

• Soil Pollution

• Factors effecting soil pollution

• Effect of soil pollution

• Control of soil pollution

Soil pollution

• 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

• Soil is the thin layer of organic and inorganic materials that covers the Earth's rocky surface.

• Organic portion, which is derived from the decayed remains of plants and animals is concentrated in the dark uppermost topsoil

• 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

Types of Soil Pollution

• Agricultural Soil Pollution

i) Pollution of surface soil

ii) Pollution of underground soil

• Soil pollution by industrial effluents and solid wastes

i) Pollution of surface soil

ii) Disturbances in soil profile

• Pollution due to urban activities

i) Pollution of surface soil

ii) Pollution of underground soil

Soil Pollution

• Contaminations of the soil by human and natural activities which may cause harmful effects on living beings

• This may be due to the following factors

• Industrial wastes: Industries are the major causes for soil pollution Textiles, steel, paper,   Cement, oil, dyeing and other industries are responsible for soil pollution.  Toxic organic compounds and phenol destroy the fertility of the soil.

• Biological agents – Fungi, protozoa, bacteria are important Biological agents for soil pollution. The human and animal wastes, garbage, waste water generates heavy soil pollution

• Radio active pollutants: Atomic reactor, nuclear radioactive devices releases radioactive pollutants. These pollutants enter the land and accumulate there by causing soil pollution

• Pesticides: Pesticides pollute the soil.

There are of two types

(1) Chlorinated hydrocarbon insecticide

(2) Organic phosphorous pesticides

• Common chlorinated hydrocarbon insecticides are DDT, BHC

• Organo phosphorous insecticides are synthetic chemicals like Malathion and parathion. DDT reduces the activity of sex hormones of male and

• Land with fungicides insecticides causes diseases to human beings

• Fertilizers: These discharge N, Na, K, S, Nitrates etc., into the soil. The nitrate causes cancer

• Polymer, Plastics & other water:  These materials appear as garbage. Solid wastes and their quantities increase day by day. They pollute the atmospheres, land and also water badly

• Agricultural practices: Modern agriculture practices pollute the soil to a large extent.   Today huge quantities of fertilizers, pesticides, and weedicides are added to increase the crop field. Apart from these farm wastes, manure debris, soil erosion containing inorganic chemicals are causing

Effect of soil pollution

• Organic wastes enter the soil pores and decompose

• Pathogenic bacteria spread infection

• Compounds containing As, Hg, Cr, Ni, Zn and Fe are toxic to life

• Fluorides affect plant development

• Water logging and salinity increase the dissolved salt content in the soil

• Some plants are very sensitive to soil PH and salinity

• Thus land becomes unfit for irrigation

Control of soil pollution

• Treat the sewage before land disposal

• Rotate the crop pattern to allow the soil replenish the nutrients

• Preserve and protect top fertile soil, control soil erosion by tree plantation

• Fertilizers may be applied only after estimating the soil and crop measures

• Production of natural fertilizers Excessive use of chemical fertilizers and insecticides should be avoided.  Bio pesticides should be used instead of toxic chemical pesticides

• Proper hygienic condition- People should be trained regarding the sanitary habits

• Recycling and reuse of waster – The wastes such as paper, plastic, metals, glasses should be recycled and used.

Summary

• Contaminations of the soil by human and natural activities which may cause harmful effects on living beings

• Various factors are responsible for soil pollution like Industrial wastes, Biological agents etc

• Soil pollution may cause pathogenic bacteria spread infection etc

• Soil pollution can be controlled by treating the sewage before land disposal, Rotate the crop pattern to allow the soil replenish the nutrients etc