Tag: human influences on the environment

Water pollution can be identified by testing its PH level and Biological Oxygen Demand (BOD)  Water pollution is the contamination of water bodies (e.g. lakes, rivers, oceans, aquifers and groundwater). This form of environmental degradation occurs when pollutants are directly or indirectly discharged into water bodies without adequate treatment to remove harmful compounds. Acid rains, dumping of chemicals into the water by individuals, industries, and communities.; steam from coal mine drainage etc affect the pH of the water in its reservoir. Thus by testing the pH of water, on the scale from 1 to 14, the pollution in water can be identified.  Biochemical oxygen demand is a measure of the quantity of oxygen used by microorganisms (e.g., aerobic bacteria)  in the oxidation of organic matter. This value varies with the amount of pollution in water hence pollution can be determined by BOD.

Sewage is waste water having food residue, animal and human excreta, detergent, discharges from industrial and commercial establishments. Degree of impurity of water due to organic matter is measured in terms of BOD or biochemical oxygen demand. BOD is the oxygen in milligrams required for 5 days in one litre of water at 20 degree centigrade for the micro organisms to metabolise organic wastes. If the water, is polluted with sewage and other organic wastes, the BOD will increase.

Biochemical Oxygen Demand (BOD) is the oxygen in milligrams required  for 5 days in one litre of water at 20 degree centigrade for the micro organisms to metabolise organic wastes present in water.

Decomposition of organic matter by microbes requires oxygen. Degree of impurity of water due to organic matter is measured in terms of Biochemical oxygen demand or (BOD). 

Domestic sewage leads to organic loading or occurrence of excess organic matter inside water. Its putrefaction decreases dissolved oxygen. Blue green algae present in the bloom also release toxins. Both toxicity and decreased oxygen level kill aquatic animals. Anaerobic putrefaction produces pollutants like methane, hydrogen sulphide, and ammonia. They kill the bloom forming plants as well. The water body comes to have foul smell, brown colouration, bad taste and oil.

Bioindicators are organisms, which have a special requirement for some specific mineral or abiotic factor or show some specific response to a particular abiotic factor. Thus, they are good indicators of environmental health. Oxygen demand, presence of minerals, occurrence of petroleum products, radioactive minerals and pollution etc. are some of the responses that can be detected using bioindicators. Lichens are very sensitive to air pollution specially due to sulphur oxides and do not grow in areas having high sulphur dioxide pollution. It is a very commonly used bio-indicator.

Organic loading is occurrence of excess organic matter inside water due to sewage disposal and eutrophication. This leads to an increase in biological oxygen demand (BOD) for putrefaction. Explosive multiplication of alga leads to algal bloom. These conditions result in decrease in dissolved oxygen in water. Both toxicity due to algal toxins and decreased levels of dissolved oxygen kill aquatic animals.

Decomposition of organic matter by microbes requires oxygen. Degree of organic impurity of water is measured in terms of 'Biological Oxygen Demand' or BOD. BOD is the oxygen in milligrams required by microorganisms to metabolise organic wastes. When more organic matter are added to water, the BOD of the water will increase.

Organic loading is occurrence of excess organic matter inside water due to sewage disposal and eutrophication. This leads to an increase in biological oxygen demand (BOD) for putrefaction by microorganisms. Also explosive multiplication of blue green alga leads to algal bloom. These conditions result in decrease in dissolved oxygen in water. Both toxicity due to algal toxins and decreased levels of dissolved oxygen kill aquatic animals.

Degree of pollution or impurities in water due to organic matter is measured in terms of 'Biological Oxygen Demand' or BOD. Biological oxygen demand or BOD is the oxygen in milligrams required for five days in one litre of water at 20 degree centigrades for the microorganisms to metabolise organic waste.