Fresh water contamination is a perennial problem that needs to be tackled at the earliest, writes Dr Uma Rajarathnam.
The quality of fresh water is a cause for concern, not only in India but in most developing countries. Fresh water contamination is a perennial problem facing these countries with the source of contamination ranging from industrial effluents, untreated waste, run-off from agricultural fields, leaching from waste dumping sites and such others.
Of the 1,500 mld of sewage generated by the 23 macro cities in India, only a fraction of it is treated with the rest flowing freely into rivers and dumping grounds.
Industrial growth, increased urbanisation and the extensive use of synthetic organic substances have had a serious impact on fresh water bodies. Both ground as well as surface water are contaminated with heavy metals and persistent organic pollutants (POPs), besides nutrients that can cause adverse health effects.
In the urban areas, typically, fresh water pipes and sewage lines pass close to each other. Leaks in these pipes lead to the mixing of sewage water with fresh water. At times, this contamination happens at the source too. Pesticide run-off from agricultural fields is a major source of contamination in the rural areas. Pesticides contain carcinogens and can affect the nervous system and cause cancer.
Untreated sewage contains microbial pathogens and these are a major cause for the spread of diseases. Besides, the organic material in untreated municipal waste uses substantial quantities of oxygen for bio-degradation, thus upsetting the ecological balance of rivers and lakes. Similarly, the high level of nutrients such as phosphorous and nitrogen in both waste water and agricultural run-off can cause eutrophication in water bodies, besides increasing the level of nitrates in drinking water far above safety levels.
A serious cause for concern is the presence of POPs in both surface and ground water. POPs are the most harmful elements affecting human health. Typically, these find their way into aquatic life and in turn into the food chain. When sea food contaminated with these chemicals is consumed, it can lead to serious health effects.
Pollution can also be airborne where air pollutants such as sulphur dioxide from power plants, steel or motor vehicles can contaminate surface water. This contamination results in the acidification of water. Besides, chemicals such as arsenic and fluoride can occur naturally in ground water. Kolar and a few other districts in Karnataka have high levels of fluoride occurring naturally in its ground water.
While small quantities of fluoride can protect against dental caries and weakening of bones, large amounts can impair health by causing dental fluorosis and damage to the bones (skeletal fluorosis). Likewise, arsenic found in the earth crust affected drinking water in six districts of West Bengal. High arsenic leads to skin lesions.
Lead is another source of contamination and this finds its way into drinking water from the water pipes which use lead. Lead does not degrade and once accumulated in the body, leads to severe health effects, especially among children ranging from reduced IQ levels to serious damage to the central nervous system and kidneys in instances of high exposure.
While chemical pollutants have serious health effects, microbial pathogens - virus bacteria, protozoa and parasitic worms - present in water are the chief causes for intestinal (enteric) diseases. These are highly infectious and transmitted mainly through water. Hepatitis, cholera, dysentery and typhoid are the most common water-borne diseases. The E Coli bacteria is an important cause of watery diarrhoea in developing countries.
A World Bank study of 2000 put the number of yearly deaths in India among children due to dirty water at 2.06 million. The UNICEF estimates our losses in terms of medical costs and loss of health at Rs 3,600 crore. India spent Rs 2,745 crore to treat diarrhoea cases alone during the period 1989-2001. The Government of India has spent about Rs 6,700 crore annually on treating water and sanitation related diseases alone.
Given the high cost of contaminated water and the resultant water-borne diseases, the way ahead would be to take steps both at the micro and macro level. To begin with, changes in behavioural patterns such as washing hands, eating washed fruits, drinking boiled water would cut down incidences of microbial diseases. Similarly, measures like safe excreta disposal and improvement in water quality as well as quantity of potable water supplied, would go a long way in reducing the incidence of water-borne diseases.
While the use of unsustainable technologies needs to be checked, indigenous low cost, on site techniques should be encouraged. For example, ecological sanitation like reed bed technologies is essentially based on the traditional understanding of environment. Besides, steps like industrial effluent control, proper treatment of municipal sewage and solid waste, and good agricultural practices to reduce the quantum of nitrates in soil would help to stem fresh water contamination right at the source.
(The author is Head - Environment Practice, Enzen Global Solutions, an energy and environment consulting firm)
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