Published on 07/10/2011
First Update 30/03/2017
Safe drinking water is a necessity for people in both the rural and urban India. The majority of people are concerned about clean water, yet may feel unaware. They may not know about the many sources of water pollution or the methods used to prevent and control it. They may not be aware of the rules and regulations adopted to protect our water. They could be intimidated by the science of water pollution control. Many of us know how important clean water is, but we may not know how to get involved to help protect it.
Socioeconomic losses due to water contagion have been grossly underestimated in India, sometimes due to lack of adequate database or due to ignoring the variety of health issues completely. Thus, there is an urgent need to have specific data bank of ground water worldwide. The UNEP stipulates that a country is considered “water-stressed” if its water availability is between 1000 to 1700 cubic meters per person. Per capita average annual availability of fresh water has reduced from 5177 cubic meters in 1951 to 1869 cubic meters in 2001 and predicted fall of up to 1341 cubic meters in 2025. According to United Nations Environmental Program (UNEP) India will possibly be “water-stressed” in coming years. About 200 millions (an estimated 90%) of the country’s water resources are polluted with untreated industrial and domestic wastes, pesticides and fertilizers. In India, ground water is being used as raw water for 85% public water supply. According to the World Health Report (1998) water supply varies widely in terms of region and country. In India, maximum population inhabits in village and slum areas where there is no safe drinking water supply. So they are always prone to loss of their lives or cost a big toll to save themselves from the occurrence of different water-borne diseases.
In India diarrhoeal disease kills 6,000 children every day apart from millions who are debilitated because of water born diseases which hinder their education and impair their ability to a decent livelihood in the future. Water contamination due to pathogenic agents, chemicals, heavy metals, pesticides, disinfectants and their by products as a consequence of industrial and agricultural activities, leaching from soil, rocks and soil, rocks and atmospheric deposition and other human activities has become a hazard to human health in several regions of the world. The microbial agents have been found commonly in drinking water are bacteria i.e. Escherchia coli, Yersinia entercolitica, Vibrio cholerae, Salmonella typhoid and different species of Campylobacter, protozoan’s i.e. Giardia intestinalis, Cryptosporidium and Entamoeba histolytica, viruses i.e. polio viruses, enteroviruses, and hepatitis viruses. Various parasitic worms and their larvae i.e. Drancunculus medinensis, ascaris, taenia, and ancylostoma have been found to make drinking water unsafe. The chemicals commonly found in drinking water above the prescribed permissible limits are fluoride, nitrate, arsenic, cadmium, chromium, lead, mercury, manganese and iron producing serious problems to human health.
Eutrophication of water bodies is caused due to diverse type of chemical and organic contaminants from various sources tend to form cyanobacterial blooms/scums on the surface of open water system and other microorganisms in different layers of water columns. The primary production rate of cyanobacterial bloom cause certain nuisance as depleting oxygen level needed for survival of aquatic fauna and cease the growth of other micro plant species. After the lysis of living or dead cells of cyanobacteria in late summer and early autumn season, produce secondary metabolites (organic compounds) which have unique structure and both poisonous and non-poisonous properties. The poisonous secondary metabolites are widely known as cyanobacteria toxins comprised into hepatotoxins, cytotoxins, neurotoxins and endotoxins which may cause deleterious effects in animals and human beings and finally result into their death. Toxic cyanobacteria (blue-green algae) found in eutrophic, municipal and residential water supplies are in increasing environmental hazard in several part of the world. Among the species causing death in livestock, Microcystis aeruginosa blooms are the most common. Since these organisms occur in both recreational and drinking water, lakes and rivers are known to be strong liver tumor promoters, they represent a health hazard to human population.
Several types of pesticides like atrazine, 2, 4-dichlorophenoxyacetic acid (2,4-D), aroclor, DDT and carbofuran have been reported in drinking water causing nausea, vomiting, dizziness and diarrhoea. Water disinfectant like chlorine in excess amount also form a number of by-products like chloramines, chlorite, trihalomethanes, chloral hydrate, bromated and chloroacetic acid with harmful long term effects on human health. Excessive level of iodine on drinking water also causes undesirable alterations in homeostasis of endocrine function.
Endemic Fluorosis is a major health issue which affects people in a number of states in India. Dental fluorosis, most symptomatically revealed through mottling of teeth and skeletal fluorosis, where the bones and joints become stiff are major concerns. Elevated fluoride levels in drinking water, a cause of fluoride related health problems have been extensively reported from Andhra Pradesh, Assam, Bihar, Delhi, Gujarat, Haryana, Jammu, & Kashmir, Karnataka, Kerala, Madhya Pradesh, Maharashtra, Orissa, Punjab, Rajasthan, Tamil Nadu, West Bengal and Uttar Pradesh. At the national level, a decade ago, the number of effected people was estimated at 66 million. Most problems are geogenic. Fluoride related problems tend to increase with age. One of the critical issues is the bioaccumulative nature of fluorides and its inverse relationship with Calcium. High altitude can also increase fluoride retention.
It has been estimated that more than five million people are at risk from arsenic poisoning and conservative figures suggest that there are over 300,000 patients who are suffering various stages of arsenicosis (UNIDO, 2001). Toxicological effects caused by arsenic are as: Hepatic response to insults by chemicals depends upon the intensity of the insults, the population of cells affected, and whether the exposure is acute or chronic. Organic arsenicals are responsible for Aplastic anaemia. Clinical manifestations include peripheral blood pancytopenia, reticulocytopenia, and bone marrow hypoplasia. Unlike most organ system, the immune system has the unique quality of not being confined to a single site within the body. Specific immunotoxic consequences of metal exposure are well documented in the literature. Metals usually exert immunosuppressive effects; however at lower concentrations, immunoenhancement is often observed. A low concentration of arsenic often leads to enhanced immune responses while exposure to higher concentrations results in immunosuppression.
Experience has shown that natural and anthropogenic hazards continue to be the primary concern in the developing and even in some of the developed countries. In India, in urban and peri-urban areas, water quality is critically affected because of intermittent supply systems. Given the poorly maintained water distribution systems, with innumerable leaks and unauthorized connections, ingression of faecally contaminated water occurs, when the pressure drops the situation is serious in the urban, peri-urban and rural areas which is reflected in the high endemicity of faecal and oral infections and other water and sanitation related diseases and periodic epidemics of the same. Water quality, its impact on human health and the standards for public consumption are issues of vital importance. Both chemical and microbial standards are critically linked to the safety and acceptability of drinking water. Development of standards and their enforcement are linked to a number of social, epidemiological and techno-economic factors. Technical, economic and institutional issues related to the water quality surveillance and management need thorough review and evaluation for the development of a time bound strategy and action plan.