POLLUTION AND HOW IT AFFECTS WATER

If you don't think pollution affects your life or are unsure just how, the best place to start is with your drinking water. Pollution of drinking water causes many deaths and much illness among urban residents all over the world. Particularly in developing countries, urban water supplies are often fouled with wastes, and clean water is scarce. A pall of atmospheric pollution hangs over many big cities, both in developed and developing countries. Sanitation design and use of water often play a major role. Water and Sanitation Urbanization can dramatically increase per capita use of freshwater.

Fast population growth with accelerated urbanization, combined with scarce water supplies and poor sanitation, means that governments often cannot supply enough water to meet demand. The number of urban residents without access to improved water sources rose from 113 million in 1990 (5% of the total urban population) to 173 million in 2000 (6% of the total urban population), according to a study by WHO and UNICEF. WHO and UNICEF define "improved" water sources as those that are better than previous sources. The term does not necessarily mean that they are safe for household use. Water is often scarce in urban areas of developing countries.

For example, in Sierra Leone in 2000 the piped water supply covered just 23% of the country's 1.8 million urban dwellers. Moreover, at least one-third of urban water supplies in Africa and Latin America and one-half in Asia operate only intermittently. Most residents of Mombasa, Kenya, for example, have water pipes in their homes, but water flows into them for an average of only three hours per day. When piped water supplies are inconsistent, people turn to other sources of water that are usually more expensive and/or unsafe. Urban water supplies often are contaminated from a variety of sources, including discharge of untreated industrial wastes, leaching from waste dumps into surface and ground water, inadequate treatment of sewage, and poor solid waste management.

Few cities in developing countries have adequate sewerage systems, and they often are limited to more advantaged areas. Purification and recycling of wastewater in sewage treatment plants is rare. In Asia, for example, treatment plants process only an estimated 35% of wastewater, and in Latin America and the Caribbean, about 14%. Worldwide, two-thirds of the sewage from urban areas is pumped untreated into lakes, rivers, and coastal waters. Even fewer people have access to improved sanitation facilities than to improve water supplies. While the numbers with access increased slightly between 1990 and 2000, the increase just kept pace with population growth.

According to WHO, nearly two-thirds of urban populations in developing countries do not have adequate sanitation in that they lack a flush toilet, a sanitary latrine, or a pit that can be covered over. While conditions maybe better in developed countries, if such conditions were to be neglected the results would be a sharp incline in the same diseases now seen across the world. Water-Related Diseases and Pollution. Worldwide, about 2.3 billion people suffer from diseases that are linked to water problems. Water-related diseases kill millions of people each year, prevent millions more from leading healthy lives, and undermine development efforts.

Nearly half of urban residents in Africa, Asia, and Latin America suffer from one or more of the main diseases associated with the inadequate provision of water and sanitation. Water-related diseases include diarrheal diseases, schistosomiasis, trachoma, ascariasis, trichuriasis, and hookworm disease . Diarrheal diseases are the major water-borne malady, responsible for 90% of the health problems related to water supply and sanitation. An estimated 4 billion cases of diarrheal disease occur every year, causing 3 million to 4 million deaths, mostly among children. Other diseases such as cholera can become endemic when there is poor food hygiene, lack of sanitation, or unsafe drinking water. Such sad results can only be averted when the pollution of source waters can be stopped and the water supply then adequately examined and treated accordingly.