is a large set of adverse effects upon water bodies (lakes, rivers, oceans, groundwater) caused by human activities. Although natural phenomena such as volcanoes, storms, earthquakes etc. also cause major changes in water chemistry and the ecological status of water, these are not deemed to be pollution. Water pollution has many causes and characteristics. Humans and other farmed organisms produce bodily wastes which enter River s, Lake s, Ocean s and other surface Water s. These wastes increase the solids suspended in the water (turbidity), they can increase the concentration of Bacteria and viruses leading to potential health impacts. Increases in Nutrient loading may lead to Eutrophication ). Organic wastes such as Sewage and farm waste impose high Oxygen demands on the receiving water leading to oxygen depletion with potentially severe impacts on the whole eco-system. Industries discharge a variety of pollutants in their Wastewater including Heavy Metals , organic toxins, oils, nutrients, and solids. Discharges can also have thermal effects, especially those form power stations, and these too reduce the available oxygen. Silt -bearing runoff from many activities including Construction sites , forestry and Farm s can inhibit the penetration of sunlight through the water column restricting Photosynthesis and causing blanketing of the lake or river bed which in turns damages the ecology.
Pollutants in water include of a wide spectrum of Chemical s, Pathogen s, and physical chemistry or sensory changes. Many of the chemical substances are Toxic or even Carcinogenic . Pathogens can obviously induce disease in either human or animal hosts. Alteration of water's physical chemistry include acidity, conductivity and temperature. excessive Nutrient loading ( Eutrophication ). Even many of the municipal water supplies in developed countries can present health risks. In the U.S.in 1972 stringent federal laws were enacted setting specific discharge limitations.
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http://financeyahoocom/columnist/article/trenddesk/3748
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Pink, Daniel H
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Yahoo
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Investing in Tomorrow's Liquid Gold
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April 19, 2006
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http://environmentaboutcom/od/environmentalevents/a/waterdayqahtm
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West, Larry
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About
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World Water Day: A Billion People Worldwide Lack Safe Drinking Water
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March 26, 2006
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Principal sources of water pollution are:
]]
Contaminants may include
Organic and
Inorganic substances.
Some salient organic water pollutants are:
Some inorganic water pollutants include:
Most water pollutants are eventually carried by the rivers into the oceans. In some areas of the world the influence can be traced hundred miles from the mouth. Indicator
Filter Feeding species such as
Copepods are used to study pollutant fates in the
New York Bight , for example. The highest
Toxin loads are not directly at the mouth of the
Hudson River , but 100 kilometers south, since several days are required for incorporation into
Plankton ic tissue. The Hudson discharge flows south along the coast due to the
Coriolis Force . Further south then are areas of
Oxygen Depletion , caused by chemicals using up oxygen and by
Algae Bloom s, caused by excess
Nutrient s from algal cell death and decomposotion. Fish and
Shellfish kills have been reported, because toxins climb the foodchain afer small fish consume
Copepods , then large fish eat smaller fish, etc. Each step up the food chain concentrates certain toxins like heavy metals and
DDT by approximately a factor of ten.
Many chemicals undergo reactive
Decay or change especially over long periods of time in
Groundwater reservoirs. A noteworthy class of such chemicals are the
Chlorinated Hydrocarbons such as
Trichloroethylene (used in industrial metal degreasing) and
Tetrachloroethylene used in the dry cleaning industry. Both of these chemicals, which are
Carcinogens themselves, undergo partial decomposition reactions leading to new hazardous chemicals.
s. Groundwater that moves through cracks and
Cave rns is not filtered and can be transported as easily as surface water. In fact this can be aggravated by the human tendency to use natural
Sinkhole s in seldomly occurring areas of
Karst topography.
There are a variety of secondary effects stemming not from the original pollutant, but a derivative condition. Some of these secondary impacts are:
In the
UK there are common law rights to protect the passage of water across land unfettered in either quality of quantity. Criminal laws dating back to the 16th century excercised some control over water pollution but it was not until the ''
River (Prevention Of Pollution )Acts 1951 - 1961 '' were enacted that any systematic control over water pollutuion was established. These laws were strengthened and extended in the ''
Control Of Pollution Act 1984 '' which has since been updated and modified by a series of further acts.
In the
USA Growing public awareness and concern for controlling water pollution led to enactment of the Federal Water Pollution Control Act Amendments of 1972. As amended in 1977, this law became commonly known as the
Clean Water Act . The Act established the basic mechanisms for regulating contaminant discharge. It established the authority for
EPA to implement wastewater standards for industry. The Clean Water Act also continued requirements to set water quality standards for all contaminants in surface waters. Further amplification of the Act continued including the enactment of the Great Lakes Legacy Act of 2002 (Public Law 107-303, November 27, 2002).
- David H.F. Liu, Bela G. Liptak, and Paul A. Bouis, '' Groundwater and Surface Water Pollution'', CRC Press (2000) ISBN 1-56670-511-8
- P.D. Abel, ''Water Pollution Biology'', Taylor & Francis (1996) ISBN 0-7484-0661-1
- Beychok, Milton R. (1967). ''Aqueous Wastes From Petroleum and Petrochemical Plants'', 1st Edition, John Wiley & Sons. LCCN 67-19834.
