Water pollution, biological effects of water polluton and control of water pollution

Water pollution

       Water pollution adversely changes the quality of water. Bacteria, viruses and algae are biological pollutants. Organic and inorganic chemical, heavy metals like arsenic, lead cadmium and mercury are chemical pollutants. Hot water from industries and oil spills from oil carriers are physical pollutants. Domestic sewage and industrial effluents are the major pollutants of water.

Domestic sewage

           Liquid wastes from kitchen, toilet and waste of cattles constitute domestic sewage. It mostly carries organic wastes which are biodegradable.

Industrial effluent 

           Both small-scale and large-scale industrial activities produce wastewater. The waste products of refineries, chemical industries and tanning factories contaminate water. Most of the components of industrial effluents are non-biodegradable.

           When domestic sewage, industrial effluents and hot water from industries are discharged into the water sources, the water is drastically polluted and not suitable for drinking. Almost all the rivers of India including Ganges are polluted.

Biological effects of water pollution

1. Polluted water causes diseases like cholera, typhoid, jaundice, amoebiasis, polio, etc.

2. Cadmium polluted water can cause a disease called itai-itai. Pain in bones and joints is the major symptom of this disease.

3. Excess of nitrate in drinking water is dangerous for human health. It reacts with hemoglobin and forms non-functional hemoglobin called methaemoglobin. It impairs oxygen transport.

4. Arsenious contaminated water causes diarrhoea, failure of peripheral nerve system and skin cancer.

5. Higher the temperature of water, lower is the rate of dissolution of oxygen in water. The discharge of hot water from industries lowers the dissolved oxygen content in water.
             High amount of fluorine is present in drinking water in 13 states of India. The maximum amount of fluorine That the human body can tolerate is 1.5 mg per litre of water. When excess of fluoride in ingested over a long period of time, it causes fluorosis. Its symptoms are dental disorder and serve skeletal disorder. Hence it is very essential to check the fluoride content of water used for drinking and cooking purposes.

Control of water pollution

1. Domestic wastewater and industrial effluents are treated suitably before releasing them into the water bodies.

2. Proper filtering mechanism must be used to control water pollution.

3. Use of herbicide and pesticide should be minimized.