Without healthy water for drinking, cooking, fishing, and farming, the human race would perish. Clean water is also necessary for recreational interests such as swimming, boating, and water skiing. Yet, when Congress began assessing national water quality during the early 1970s, it found that much of the country's groundwater and surface water was contaminated or severely compromised. Studies revealed that the nation's three primary sources of water pollution—industry, agriculture, and municipalities—had been regularly discharging harmful materials into water supplies throughout the country over a number of years.
These harmful materials included organic wastes, sediments, minerals, nutrients, thermal pollutants, toxic chemicals, and other hazardous substances. Organic wastes are produced by animals and humans, and include such things as fecal matter, crop debris, yard clippings, food wastes, rubber, plastic, wood, and disposable diapers. Such wastes require oxygen to decompose. When they are dumped into streams and lakes and begin to break down, they can deprive aquatic life of the oxygen it needs to survive.
Sediments may be deposited into lakes and streams through soil erosion caused by the clearing, excavating, grading, transporting, and filling of land. Minerals, such as iron, copper, chromium, platinum, nickel, zinc, and tin, can be discharged into streams and lakes as a result of various mining activities. Excessive levels of sediments and minerals in water can inhibit the penetration of sunlight, which reduces the production of photosynthetic organisms.
Nutrients, like phosphorus and nitrogen, support the growth of algae and other plants forming the lower levels of the food chain. However, excessive levels of nutrients from sources such as fertilizer can cause eutrophication, which is the overgrowth of aquatic vegetation. This overgrowth clouds the water and smothers some plants. Over time, excessive nutrient levels can accelerate the natural process by which bodies of water evolve into dry land.
Thermal pollution results from the release of heated water into lakes and streams. Most thermal pollution is generated by power plant cooling systems. Power plants use water to cool their reactors and turbines, and discharge it into lakes and tributaries after it has become heated. Higher water temperatures accelerate biological and chemical processes in rivers and streams, reducing the water's ability to retain dissolved oxygen. This can hasten the growth of algae and disrupt the reproduction of fish.
Toxic chemicals and other hazardous materials present the most imminent threat to water quality. The environmental protection agency (EPA) has identified 582 highly toxic chemicals, which are produced, manufactured, and stored in locations across the United States. Some chemical plants incinerate toxic waste, which produces dangerous by-products like furans and chlorinated dioxins, two of the most deadly carcinogens known to the human race. Other hazardous materials are produced or stored by households (motor oil, antifreeze, paints, and pesticides), dry cleaners (chlorinated solvents), farms (insecticides, fungicides, rodenticides, and herbicides), and gas stations and airports (fuel).
Water pollution regulation consists of a labyrinth of state and federal statutes, administrative rules, and common-law principles.
Federal statutory regulation of water pollution has been governed primarily by three pieces of legislation: the Refuse Act, the Federal Water Pollution Control Act, and the Clean Water Act. The Rivers and Harbors Appropriations Act of 1899, 33 U.S.C.A. § 401 et seq., commonly known as the Refuse Act, was the first major piece of federal legislation regulating water pollution. The Refuse Act set effluent standards for the discharge of pollutants into bodies of water. An effluent standard limits the amount of pollutant that can be released from a specific point or source, such as a smokestack or sewage pipe. The Refuse Act flatly prohibited pollution discharged from ship and shore installations.
The Refuse Act was followed by the Federal Water Pollution Control Act of 1948 (FWPCA), 33 U.S.C.A. § 1251 et seq. Instead of focusing on sources of pollution through effluent standards, the FWPCA created water quality standards, which prescribed the levels of pollutants permitted in a given body of water. Where the Refuse Act concentrated on deterring specific types of polluters, the FWPCA concentrated on reducing specific types of pollution.
Since 1972, federal regulation of water pollution has been primarily governed by the Clean Water Act (CWA) 33 U.S.C.A. § 1251 et seq., which overhauled FWCPA. The CWA forbids any person to discharge pollutants into U.S. waters unless the discharge conforms with certain provisions of the act. Among those provisions are several that call upon the EPA to promulgate effluent standards for particular categories of water polluters.
To implement these standards, the CWA requires each polluter to obtain a discharge permit issued by the EPA through the National Pollutant Discharge Elimination System (NPDES). Although the EPA closely monitors water pollution dischargers through the NPDES, primary responsibility for enforcement of the CWA rests with the states. Most states have also drafted permit systems similar to the NPDES. These systems are designed to protect local supplies of groundwater, surface water, and drinking water. Persons who violate either the federal or state permit system face civil fines, criminal penalties, and suspension of their discharge privileges.
The CWA also relies on modern technology to curb water pollution. It requires many polluters to implement the best practicable control technology, the best available technology economically achievable, or the best practicable waste treatment technology. The development of such technology for nontoxic polluters is based on a cost-benefit analysis in which the feasibility and expense of the technology is balanced against the expected benefits to the environment.
The CWA was amended in 1977 to address the nation's increasing concern about toxic pollutants. Pursuant to the 1977 amendments, the EPA increased the number of pollutants it deemed toxic from nine to 65, and set effluent limitations for the 21 industries that discharge them. These limitations are based on measures of the danger these pollutants pose to the public health rather than on cost-benefit analyses.
Many states have enacted their own water pollution legislation regulating the discharge of toxic and other pollutants into their streams and lakes.
The mining industry presents persistent water pollution problems for state and federal governments. It has polluted over a thousand miles of streams in Appalachia with acid drainage. In response, the affected state governments now require strip miners to obtain licenses before commencing activity. Many states also require miners to post bonds in an amount sufficient to repair potential damage to surrounding lakes and streams. Similarly, the federal government, under the Mineral Leasing Act, 30 U.S.C.A. § 201 et seq., requires each mining applicant to "submit a plan of construction,
operation and rehabilitation" for the affected area, that takes into account the need for "restoration, revegetation and curtailment of erosion."
The commercial timber industry also presents persistent water pollution problems. Tree harvesting, yarding (the collection of felled trees), and road building can all deposit soil sediments into watercourses, thereby reducing the water quality for aquatic life. State governments have offered similar responses to these problems. For instance, clear-cutting (the removal of substantially all the trees from a given area) has been prohibited by most states. Other states have created buffer zones around particularly vulnerable watercourses, and banned unusually harmful activities in certain areas. Enforcement of these water pollution measures has been frustrated by vaguely worded legislation and a scarcity of inspectors in several states.
State and federal water pollution statutes provide one avenue of legal recourse for those harmed by water pollution. The common-law doctrines of nuisance, trespass, negligence, strict liability, and riparian ownership provide alternative remedies.
Nuisances can be public or private. Private nuisances interfere with the rights and interests of private citizens, whereas public nuisances interfere with the common rights and interests of the people at large. Both types of nuisance must result from the "unreasonable" activities of a polluter, and inflict "substantial" harm on neighboring landowners. An injury that is minor or inconsequential will not result in liability under common-law nuisance. For example, dumping trace amounts of fertilizer into a stream abutting neighboring property will not amount to a public or private nuisance.
The oil and agricultural industries are frequently involved in state nuisance actions. Oil companies often run afoul of nuisance principles for improperly storing, transporting, and disposing of hazardous materials. Farmers represent a unique class of persons who fall prey to water pollution nuisances almost as often as they create them. Their abundant use of fungicides, herbicides, insecticides, and rodenticides makes them frequent creators of nuisances, and their use of streams, rivers, and groundwater for irrigation systems makes them frequent victims.
Nuisance actions deal primarily with continuing or repetitive injuries. Trespass actions provide relief even when an injury results from a single event. A polluter who spills oil, dumps chemicals, or otherwise contaminates a neighboring water supply on one occasion might avoid liability under nuisance law but not under the law of trespass. Trespass does not require proof of a substantial injury. However, only nominal damages will be awarded to a landowner whose water supply suffers little harm from the trespass of a polluter.
Trespass requires proof that a polluter intentionally or knowingly contaminated a particular course of water. Yet, water contamination often results from unintentional behavior, such as industrial accidents. In such instances, the polluter may be liable under common-law principles of negligence. Negligence occurs when a polluter fails to exercise the degree of care that would be reasonable under the circumstances. Thus, a landowner whose water supply was inadvertently contaminated might bring a successful lawsuit against the polluter for common-law negligence where a lawsuit for nuisance or trespass would fail.
Even when a polluter exercises the utmost diligence to prevent water contamination, an injured landowner may still have recourse under the doctrine of strict liability. Under this doctrine, polluters who engage in "abnormally dangerous" activities are held responsible for any water contamination that results. Courts consider six factors when determining whether a particular activity is abnormally dangerous: the probability that the activity will cause harm to another, the likelihood that the harm will be great, the ability to eliminate the risk by exercising reasonable care, the extent to which the activity is uncommon or unusual, the activity's appropriateness for a particular location, and the activity's value or danger to the community.
The doctrine of strict liability arose out of a national conflict between competing values during the industrial revolution. This conflict pitted those who believed it was necessary to create an environment that promoted commerce against those who believed it was necessary to preserve a healthy and clean environment. For many years, courts were reluctant to impose strict liability on U.S. businesses, out of concern over retarding industrial growth.
Since the early 1970s, courts have placed greater emphasis on preserving a healthy and clean environment. In Cities Service Co. v. State, 312 So. 2d 799 (Fla. App. 1975), the court explained that "though many hazardous activities … are socially desirable, it now seems reasonable that they pay their own way." Cities Service involved a situation in which a dam burst during a phosphate mining operation, releasing a billion gallons of phosphate slime into adjacent waterways, where fish and other aquatic life were killed. The court concluded that this mining activity was abnormally dangerous.
Some activities inherently create abnormally dangerous risks to abutting waterways. In such cases, courts do not employ a balancing test to determine whether an activity is abnormally dangerous. Instead, they consider these activities to be dangerous in and of themselves. The transportation and storage of high explosives and the operation of oil and gas wells are activities courts have held to create inherent risks of abnormally dangerous proportions.
The doctrine of riparian ownership forms the final prong of common-law recovery. A riparian proprietor is the owner of land abutting a stream of water, and has the right to divert the water for any useful purpose. Some courts define the term useful purpose broadly to include almost any purpose whatsoever, whereas other courts define it more narrowly to include only purposes that are reasonable or profitable.
In any event, downstream riparian proprietors are often placed at a disadvantage because the law protects upstream owners' initial use of the water. For example, an upstream proprietor may construct a dam to appropriate a reasonable amount of water without compensating a downstream proprietor. However, cases involving thermal pollution provide an exception to this rule. For example, downstream owners who use river water to make ice can seek injunctive relief to prevent upstream owners from engaging in any activities that raise the water temperature by even one degree Fahrenheit.
Andreen, William L. 2003. "The Evolution of Water Pollution Control in the United States—State, Local, and Federal Efforts, 1789–1972." Stanford Environmental Law Journal 22 (January).
Findley, Roger W., Daniel A. Farber, and Jody Freeman. 2003. Cases and Materials on Environmental Law. 6th ed. St. Paul, Minn.: West.
Hipfel, Steven J. 2001. "Enforcement of Nonpoint Source Water Pollution Control and Abatement Measures Applicable to Federal Facilities, Activities and Land Management Practices under Federal and State Law." Environmental Lawyer 8 (September).
Houck, Oliver A. 2002. The Clean Water Act TMDL Program: Law, Policy, and Implementation. 2d ed. Washington, D.C.: Environmental Law Institute.
Ryan, Mark A., ed. 2003. The Clean Water Act Handbook. 2d ed. Chicago: Section of Environment, Energy, and Resources, American Bar Association.
"Water Pollution." West's Encyclopedia of American Law. . Encyclopedia.com. (February 20, 2017). http://www.encyclopedia.com/law/encyclopedias-almanacs-transcripts-and-maps/water-pollution
"Water Pollution." West's Encyclopedia of American Law. . Retrieved February 20, 2017 from Encyclopedia.com: http://www.encyclopedia.com/law/encyclopedias-almanacs-transcripts-and-maps/water-pollution
Water Pollution: Freshwater
Water Pollution: Freshwater
Freshwater pollution is the contamination of inland water (not saline) with substances that make it unfit for its natural or intended use. Pollution may be caused by fecal waste, chemicals, pesticides, petroleum, sediment, or even heated discharges. Polluted rivers and lakes are unfit for swimming or fishing; polluted water is unsafe to drink.
For centuries, fecal waste and other pollutants were dumped in rivers, with "dilution the solution" to pollution. In the mid-twentieth century, many American rivers and streams were open sewers, choking on everything from human waste to highly toxic industrial discharges. New York City alone pumped a half billion gallons of raw sewage into its harbor every day. As pollution levels grew, so did the impacts. "No swimming" signs became the norm. Lake Erie was dying. The Hudson River's commercial striped bass fishery, once valued at $40 million a year, was closed and it became illegal to sell oysters from Oyster Bay, Long Island. And then, in June 1969, Ohio's Cuyahoga River caught fire.
The damning image of a river in flames is credited by many for passage of the Federal Water Pollution Control Act of 1972. The U.S. Environmental Protection Agency (EPA) set standards to regulate the discharge of industrial and municipal waste—so-called end-of-the-pipe pollution. With them came significant federal funding to help localities improve wastewater treatment. Billions of dollars have been invested since 1972 building and upgrading sewage treatment facilities.
Improvements in municipal wastewater treatment have been matched by progress in the private sector. Nationally, more than thirty thousand major industrial dischargers pretreat their wastewater before it enters local sewers. By 2000, some 75 percent of toxic discharges, including heavy metals and PCBs, were being prevented.
Surface Water Pollution
Freshwater makes up less than three percent of earth's water, but is the source of virtually all drinking water. In 2002, each U.S. household used an average of 94,000 gallons of water per year. Some 55 percent of that water comes from reservoirs, rivers, and lakes, and a 2000 survey published in EPA's National Water Quality Inventory found almost 40 percent of U.S. rivers and 45 percent of lakes are polluted. These sources, called surface water, are vulnerable to pollution discharged out of pipes and precipitating out of the air but the primary source of their pollution today is runoff, pollutants washing off the land.
These nonpoint or scattered sources are not easily traceable. Pesticides and fertilizers used in agriculture and on golf courses and suburban lawns account for a major portion of nonpoint source pollution. Runoff from parking lots and roads flush spilled oil and gasoline and road salt into lakes and streams. Runoff containing manure from livestock and poultry producers has been a major source of surface water pollution. More than 150 pathogens found in livestock manure pose risks to humans. In 2003, concentrated animal feeding operation guidelines, or CAFO standards, were finalized requiring inspection of waste lagoons and outdoor manure tanks, as well as permits for applying manure on land.
Air pollutants such as dioxin and mercury along with sulfur and nitrogen oxides precipitate into lakes and rivers by rainfall in the form of acid rain. More than 95 percent of rainwater tested at four sites in Indiana between 2001 and 2002 contained unsafe levels of mercury according to a National Wildlife Federation report.
Point sources, such as chemical and municipal wastewater treatment plants, were the leading source of contamination for about ten percent of river and lake water according to the 2000 National Water Quality Inventory. Toxic chemicals, although now regulated, can still be discharged directly into surface water. AK Steel Corporation in Pennsylvania discharged the largest amount of any industrial pollutant, about 28 million pounds of nitrate compounds, to surface water between 1998 and 2000, according to the Toxic Release Inventory.
Other sources of surface water pollution include silt washed into streams and lakes that smothers organisms on the lake floor, upsetting or destroying aquatic ecosystems. Thermal pollution such as an influx of warm water from cooling towers for power ecosystems. plants also has a detrimental effect on aquatic
The recent discovery of surface-water contamination by minute amounts of pharmaceuticals and personal-care products, including synthetic hormones from birth control pills, is being investigated to determine whether it poses a threat to humans, aquatic species, or wildlife. Water Quality Act amendments of 1987 established a $400-million program to help states to develop and implement nonpoint source management programs based on watershed protection.
Water contained in the pores of soil or in aquifers is called groundwater. About 40 percent of U.S. municipal water comes from groundwater and an additional forty million people, including most of the rural population, draw drinking water from domestic wells. Groundwater, while protected by the filtering action of soil, can be contaminated by leaking municipal landfills, sewage lagoons, and chemicals from industrial activity. Centers for Disease Control data shows that 318 waterborne disease outbreaks associated with groundwater systems occurred between 1971 and 1996. Leaking underground oil tanks and spills at gas stations account for oil and other chemicals such as benzene and methyl-tertiary-butyl ether (MBTE) found in ground-water. More than 400,000 leaking underground storage tanks were reported in the United States in 2001. Pesticides and agricultural fertilizers drain into groundwater polluting it with carcinogenic chemicals and nitrates.
The Safe Drinking Water Act of 1974 (SWDA) regulates groundwater. More than eighty possible contaminants are monitored, including carcinogens such as tetrachloroethylene, discharged from dry cleaners. Health effects of these contaminants range from increased cancer risk, intestinal lesions, kidney damage, and reproductive difficulties, to gastrointestinal distress. Municipal and private water suppliers are responsible for seeing that contaminants do not exceed the limits set by the EPA.
Human and Environmental Health Effects
Fertilizer, animal manure, and waste-treatment plant effluent all contain nutrients that stimulate excessive plant and algal growth in freshwater bodies. When the plants die and decompose, dissolved oxygen is depleted, causing die-offs of fish and other species living in the water. Persistent organochlorine insecticides, such as DDT, deposited in lake sediments can bioaccumulate, harming the fish and birds that eat them. Pyrethroid insecticides, though derived from chrysanthemums, are extremely toxic to aquatic organisms. Estrogen-mimicking substances such as some pesticides and industrially produced chemicals have been shown to interfere with the reproductive system of fish.
Human and animal fecal waste contain disease-carrying organisms such as the bacterium Escherichia coli (E. coli) and pathogens that causes cholera, typhoid, and cryptosporidiosis. Cholera is rarely seen in the United States, but E. coli outbreaks are not rare, and in 1993, more than fifty people died, and an estimated 400,000 became ill from a massive outbreak of cryptosporidiosis in Milwaukee, Wisconsin. The outbreak was attributed to a failure in drinking water treatment, allowing the cyst form of the parasite, introduced by animal waste, to pass into tap water and be ingested. Ten outbreaks of cryptosporidiosis were reported in the United States between 1990 and 2000.
Mercury bioaccumulates in fish and can damage the nervous systems and brains of humans. It can interfere with normal behavior in birds, such as loons, causing them to spend less time looking for food or incubating eggs. About one-quarter of breeding adult loons have higher-than-normal (10 parts per million) levels of mercury. To protect people from eating contaminated fish, states and local governments post fish-consumption advisories when contaminant levels become unsafe. There were 2,800 advisories posted in the United States in 2002, alerting people to high levels of mercury, PCBs, chlordane, dioxins, and DDT in fish.
Prevention and Abatement
Once water is contaminated, it is difficult, expensive, and sometimes impossible to remove pollutants. Technologies to remove contaminants from groundwater are air stripping, granular activated carbon, and advanced oxidation. Air stripping involves pumping out the contaminated water, then heating it to evaporate the contaminant. The cleaned water is reinjected into the ground. Pumping out contaminated water and absorbing the pollutant on activated charcoal can remove less volatile compounds. Ninety percent of trichloroethylene was removed from NASA's launch complex thirty-four groundwater cleanup site on Cape Canaveral Air Force Station by thermal treatment. In this method an electric current heats soil and water, evaporating some water and the contaminant, which is carried out of the ground by the force of the steam and collected in recovery wells.
Preventing pollution is obviously important. Drinking water suppliers have discovered that watershed protection is cost-effective because it reduces pollution and cuts the cost of drinking water treatment. A watershed is the area that drains into surface or groundwater and keeping that area free from development and agricultural runoff are among the goals of watershed protection. The Barnes Aquifer in Massachusetts supplies water to sixty thousand residents and the aquifer's recharge area is under heavy development pressure from large-scale residential subdivisions. Municipal wells have been contaminated with traces of ethylene dibromide and trichloroethylene. After learning about watershed protection, citizens voted against proposed changes to zoning that would have increased the number of new homes and increased the potential for groundwater pollution. And by investing $1 billion in watershed protection, New York City, with an enormous reservoir system, has avoided having to build water-filtration facilities, saving construction costs of some $8 billion.
The United Nations (UN) theme for World Environment Day 2003 was "Water: Two Billion People are Dying for It!" It was not en exaggeration. The UN reports that one person in six lives without regular access to safe drinking water. Over twice that number—2.4 billion people—lack access to adequate sanitation. Water-related diseases kill a child every eight seconds, and are responsible for 80 percent of all illnesses and deaths in the developing world. Cholera outbreaks, due to water contaminated with raw sewage, occur regularly in India and Bangladesh and less frequently in many other countries. In Africa in 1997, 5,853 deaths due to cholera were reported to the World Health Organization. It is a situation, the UN said, "made all the more tragic by our long-standing knowledge that these diseases are easily preventable."
see also: Acid Rain; Agriculture; Clean Water Act; Cryptosporidiosis; DDT (Dichlorodiphenyl trichloroethane); Health, Human; Nonpoint Source Pollution; PCBs (Polychlorinated Biphenyls); Point Source; Snow, John; Wastewater Treatment; Water Treatment.
Pielou, E.C. (1998). Fresh Water. Chicago and London: The University of Chicago Press.
Natural Resources Defense Council. "What's on Tap: Grading Water in 19 U.S. Cities." Available from http://www.nrdc.org/water/drinking/uscities/contents.asp.
U.S. Environmental Protection Agency. Browse EPA Topics. Available from http://www.epa.gov/ebtpages/alphabet.html.
U.S. Environmental Protection Agency. Clean Water Act. Available from http://www.epa.gov/r5water/cwa.htm.
U.S. Environmental Protection Agency. Concentrated Animal Feeding Operation Final Rule. Available from http://cfpub.epa.gov/npdes/afo/cafofinalrule.cfm.
U.S. Environmental Protection Agency. List of Drinking Water Contaminants and their MCLs. Available from http://www.epa.gov/safewater/mcl.html#mcls.
U.S. Environmental Protection Agency. Polluted Runoff (Nonpoint Source Pollution). Available from http://www.epa.gov/OWOW/NPS/facts/point1.htm.
U.S. Environmental Protection Agency. Proposed Groundwater Rule. Available from http://www.epa.gov/OGWDW/gwr.html.
U.S. Environmental Protection Agency. Safe Drinking Water Act. Available from http://www.epa.gov/safewater/sdwa/sdwa.html.
U.S. Environmental Protection Agency. 2000 National Water Quality Inventory. Available from http://www.epa.gov/305b/2000report.
U.S. Environmental Protection Agency's Water Science Great Lakes Initiative Topic. Available from http://www.epa.gov/ost/GLI/mixingzones/finalfact.html.
U.S. Environmental Protection Agency. Fish Advisories. Available from http://www.epa.gov/waterscience/fish.
U.S. Geological Survey National Water Quality Assessment Program. Available from http://water.usgs.gov/nawqa.
You can help prevent water pollution by simply not littering. Street trash that washes down storm drains is a major source of floatable debris. Properly dispose of used oil; oil poured down storm drains and sewers is a major source of petroleum pollution. Use nonphosphate detergents for dish and clothes washing. Don't overfertilize lawns and use integrated pest management practices to reduce pesticide use. Use hazardous waste collection programs to dispose of batteries, fluorescent lights that contain mercury, unused oil, paint remover, pesticides and old household chemicals.
The Great Lakes Basin includes areas of the eight Great Lakes states: New York, Pennsylvania, Ohio, Minnesota, Indiana, Illinois, Wisconsin, and Michigan. In 1995, the U.S. Environmental Protection Agency (EPA) and the Great Lakes states agreed to a plan called the Great Lakes Initiative, aimed at reducing pollution and restoring the health of the Great Lakes. The plan included setting water quality standards for twenty-nine pollutants. In 2000, the EPA initiated a ten-year phase-out of the use of mixing zones for bioaccumulative chemicals in the Great Lakes. The EPA says this ruling will reduce discharges of toxic chemicals by 700,000 pounds a year.
"Water Pollution: Freshwater." Pollution A to Z. . Encyclopedia.com. (February 20, 2017). http://www.encyclopedia.com/environment/educational-magazines/water-pollution-freshwater
"Water Pollution: Freshwater." Pollution A to Z. . Retrieved February 20, 2017 from Encyclopedia.com: http://www.encyclopedia.com/environment/educational-magazines/water-pollution-freshwater
Water Pollution: Marine
Water Pollution: Marine
Marine pollution is the release of by-products of human activity that cause harm to natural marine ecosystems. The pollutants may be sewage, farm waste, toxic chemicals, or inert materials that may smother, choke, or strangle living organisms.
Sewage, Animal Waste, and Fertilizers
Sewage, animal waste, and chemical fertilizers all have a high content of nitrogen and phosphorus. Artificially high levels of these substances in the water promote excessive growth of microscopic or macroscopic plants, in a process called eutrophication . When these plants accumulate, die, and decay, they cause low oxygen content in the water. Even if sewage is treated to remove solids, the liquid discharged contains high levels of nitrogen and phosphorus. Intensive cultivation of animals in feedlots, or application of more fertilizer than a crop can absorb, also cause runoff rich in nitrogen and phosphorus that find their way into rivers and estuaries. Vehicle exhausts and industrial chimneys are large sources of nitrogen compounds that are transported in the atmosphere and deposited in coastal waters.
On a global scale, agricultural runoff is the most important source of eutrophication, but atmospheric deposition is the fastest-growing source. It is the largest source of nitrogen off the coast of the northeastern United States, in the western Baltic Sea, and in the western Mediterranean Sea. International agencies consider that, worldwide, eutrophication is the most serious pollution problem in coastal waters. For example, in the Gulf of Mexico, off the mouth of the Mississippi River, water near the bottom has severely reduced oxygen content over a very large area, sixteen thousand square kilometers (6,200 square miles) by 1998. Mobile animals such as fish and shrimp leave the hypoxic area, but sedentary animals such as clams and worms are killed in large numbers.
A classic example of eutrophication and its treatment occurred in the estuary of the River Thames, near London, England. In the 1950s the water was severely hypoxic for thirty-five kilometers (twenty-two miles) below London Bridge. After several sewage treatment plants were built, the water returned to a well-oxygenated state and migratory fish such as salmon once again ascend the river. In the case of the Mississippi River, treatment of the eutrophication is more difficult because runoff from agricultural land is the major cause of the problem, and more than half of the agricultural land in the United States drains into the Mississippi basin. Cleaning up the pollution would involve changes in farming methods on a national scale.
Eutrophication has important indirect effects. The plants known as sea grasses, which grow in the shallow water of estuaries , provide food and shelter for a wide range of animals, including geese, turtles, manatees, and fish. In eutrophicated water, the dense microscopic plant life significantly reduces the penetration of light and smothers the sea grasses. In Chesapeake Bay, Maryland, eutrophication caused an area of sea grasses to decrease by twothirds between 1960 and 1980, and there was a corresponding decrease in landings of fish and crabs. Similar effects have been observed in Australia.
Red tides, or harmful algal blooms, are associated with eutrophication. Single species of phytoplankton multiply at the expense of all other species
and become so abundant that the water is discolored. Many bloom species produce toxic substances. During the 1990s in estuaries located in the southeastern United States, there were numerous cases of blooms of Pfiesteria piscida, a dinoflagellate that produced a toxin which killed thousands of fish. The source of the nutrients support Pfiesteria is believed to be agricultural runoff or sewage discharge. Other types of blooms are ingested by shellfish, which become toxic for humans who consume them, causing partial paralysis, memory loss, or even death. Toxic blooms have been reported much more frequently in the 1990s than in the past, and the spread of eutrophication is believed to be a contributing factor.
Pollution and Coral Reefs
On coral reefs, eutrophication causes seaweed to grow and smother the corals. Several kinds of environmental problems interact with eutrophication to cause the deterioration of coral reefs. Overharvesting of the fish and invertebrates that eat seaweed accelerates the smothering. Careless development along coastlines and in river basins leads to soil erosion and the transport of heavy loads of silt and clay, which settle on the corals and smother them. Oil spills also take their toll. When corals are exposed to abnormally high water temperature, they respond by discharging the microscopic algae living within their tissues. Sometimes they recover, but often they die. These episodes, called coral bleaching, became much more frequent during the 1990s and are believed to be caused by global warming. The result of pollution and global warming is that at least half of the area of coral reefs in southeast Asia is in poor condition, and in parts of the Caribbean Sea only 5 percent of the reef area consists of living coral.
Metals and Organic Contaminants
Industrial effluents often contain metallic compounds. For example, Halifax, a small city in eastern Canada, discharged into its harbor during the 1990s about thirty-three tons of zinc and thirty-one tons of lead per year, with lesser amounts of copper and other metals. These metals are held in the sediment in a relatively inert form, but if stirred up into the water column, they become oxygenated and toxic. Tin is another common pollutant in harbors. It occurs as tributyltin (TBT), which is used as a component of antifouling paints on the undersides of ships. When taken up by shellfish, it accumulates in their tissues and has proved toxic to the shellfish and to organisms that consume them. The United States began to phase out TBT in 1988, and it will be banned internationally beginning in 2008.
Industry also produces organic compounds such as polychlorinated biphenyls (PCBs) and various pesticides. These accumulate in the fatty tissue of plants and animals low in the food chain, and as they pass through the food web to larger and long-lived animals, there is an increase in concentration of the substances in their fat, a process known as bioaccumulation. The St. Lawrence River, which drains the Great Lakes, has accumulated large amounts of organochlorines , which have amassed in the tissues of Beluga whales. During the 1990s, the level of this pollution was much reduced, and the whales have been protected from hunting, but their population fails to increase. Many animals have tumors and disease. There is mounting evidence that chronic exposure to contaminants causes suppression of the immune responses of marine mammals. Similar problems have occurred with seals in the Baltic Sea.
The most serious types of oil pollution occur when an oil tanker goes ashore or hits a reef and spills its contents. As the oil drifts ashore, great damage is done to beaches, rocky shores, salt marshes, or mangrove forests. Cleanup is often attempted using mechanical means, or the application of dispersants, with mixed results. Usually, a proportion of native organisms are killed, but given time, the lighter fractions of oil evaporate, while the heavier fractions are decomposed by photochemical processes and microorganisms. International law now requires that vessel owners be responsible for any loss of oil, damage to existing ecosystems, and the costs of recommended cleanup.
Chronic low levels of oil pollution, resulting from accidental spills when loading or unloading, or from washing out oil tanks, are widespread and of significant concern. For example, it has been determined that corals around an oil terminal in the Red Sea have experienced lower growth rates and poor reproduction as a result of chronic low-level oil pollution.
Oil pollution of the open ocean is also a major concern. When Thor Heyerdahl crossed the South Pacific on the raft Kon-Tiki in 1947 he reported pristine waters, but his Ra expedition across the Atlantic twenty-two years later encountered oil slicks on forty-three of fifty-seven days at sea. The International Convention for Prevention of Pollution from Ships was devised in 1973 and modified by the Protocol of 1978. Oceangoing vessels are subject to strict regulations concerning the discharge of oil, bilge water, and ballast water, and are forbidden to dump garbage and other solid waste. Accidental spills must be reported.
Marine beaches serve as natural traps for marine debris. Globally, the most common materials are plastics, followed by glass and metal. The chief dangers to marine life result from the ingestion of these fragments, which may block the gut, and from entangling, which may cause suffocation or prevent locomotion and feeding. In a survey of U.S. beaches close to urban centers, cigarette butts were the most abundant debris, followed by packaging items (boxes, bags, caps, lids), medical waste, and sewage. A high proportion of this material reached the sea by way of sewers. Even street litter can be washed into surface drains and then to the sea. The dumping of sewage and waste by ships is another source. Public revulsion at the state of U.S. beaches was a key factor in the enactment of stronger environmental protection laws, like the Ocean Dumping Ban Act of 1988 that prohibited the dumping of sewage into the ocean. On sites more remote from cities, pieces of rope and netting are the most common types of marine debris.
Reduction and Regulation of Marine Pollution
There is much that individuals can do to prevent marine pollution: avoid putting toxic substances into drains, avoid dropping litter, minimize the use of pesticides and fertilizers, reduce automobile emissions, and pressure your local government for sewage treatment in the community if it does not yet exist. Larger-scale problems require legislation and enforcement, ranging from the local laws of coastal states in the United States, through national laws such as the Clean Water Act and Clean Air Act, to international conventions such as the International Convention for the Prevention of Pollution from Ships. Such laws are effective only if they have the support of the people.
see also Acid Rain; Clean Water Act; Cryptosporidiosis; Fish Kills; Hypoxia; Mercury; Ocean Dumping; PCBs (Polychlorinated Biphenyls); Petroleum; Rivers and Harbors Appropriations Act; Snow, John; Water Treatment; Wastewater Treatment.
clark, r.b.; frid, c; and attrill, m. (2001). marine pollution, 5th edition. oxford, uk: oxford university press.
pelley, j. (1998). "is coastal eutrophication out of control?" environmental science and technology 32:462a–466a.
global investigation of pollution in the marine environment (gipme). "marine pollution programme." available from http://ioc.unesco.org/iocweb.
ocean conservancy. available from http://www.oceanconservancy.org.
Kenneth H. Mann
Coral grows a new layer each year, much as a tree adds a new ring each year. Scientists analyzing layers of Bermudan coral have discovered an environmental record dating back to the mid-1800s. Marine pollution can be measured across the Industrial Revolution. Marine levels of lead have dropped dramatically since the phaseout of leaded gasoline but levels of lead in the Atlantic are still double their preindustrial concentrations.
When Thor Heyerdahl, a Norwegian biologist (1914–2002), sailed the balsa wood raft named Kon-Tiki, from Peru to Polynesia in 1947, he saw no pollution in the Pacific Ocean. Just over twenty years later, in 1970, when sailing a papyrus reed boat from Morocco to Barbados, Heyerdahl saw extensive marine pollution including oily wastes, plastic bottles and other trash floating in the water. He radioed the United Nations to report that floating lumps of solidified, asphalt-like oil polluted over one thousand miles of the Atlantic Ocean. After seeing the extent of the ocean's pollution first hand, Heyerdahl became actively involved in fighting marine pollution. In 1999, with the Norwegian Shipowners Organization, he initiated the Thor Heyerdahl International Maritime Environmental Award to be given for improvement of the global environment.
Thousands of volunteers in every U.S. state and territory as well as in more than fifty other countries pick up tons of marine debris each fall in a one-day coastal cleanup. The Ocean Conservancy, which organizes the annual cleanup, collects data on the debris to determine sources of pollution. The most common item washed up on the shoreline? Cigarette butts and filters—a total of 1,640,614 were picked up in 2001. Volunteers also found 259 entangled animals, most snared in nylon fishing line.
"Water Pollution: Marine." Pollution A to Z. . Encyclopedia.com. (February 20, 2017). http://www.encyclopedia.com/environment/educational-magazines/water-pollution-marine
"Water Pollution: Marine." Pollution A to Z. . Retrieved February 20, 2017 from Encyclopedia.com: http://www.encyclopedia.com/environment/educational-magazines/water-pollution-marine
Water pollution occurs when undesirable foreign substances are introduced into natural water. The substances may be chemical or biological in nature. Common pollutants include human or animal waste; disease-producing organisms; radioactive materials; toxic metals such as lead or mercury; agricultural chemicals such as pesticides, herbicides, or fertilizers; acid rain ; and high-temperature water discharged from power plants, often called "thermal pollution." Pollutants in water are dangerous for human or animal consumption and harm crops. High temperatures may cause algae to grow rapidly, rendering water unfit for consumption.
Point sources of pollution, such as an oil leak from a pipeline or chemical waste from a factory, can often be controlled. Nonpoint sources, such as runoff sediment and nitrate-rich water from feedlots represent larger amounts of pollution and are difficult to identify and remedy. Pollution from nonpoint sources may pass into streams or aquifers, covering a wide area.
Although water has been identified on several planets, none has as much water as Earth, of which 70 percent is covered with water. Approximately 97.4 percent of the water on Earth is found in oceans and is too salty for human consumption. An additional 2.6 percent is freshwater found in underground bodies of water called aquifers or frozen in glaciers or polar ice caps. Less than 0.02 percent of Earth's water is present in lakes, rivers, or the atmosphere.
In a few places, water is pure enough to drink directly from wells or springs, but increasingly water must be treated to remove dangerous contaminants, and substances such as chlorine, chloramines, or ozone must be added to kill harmful bacteria.
Pollutants in water are commonly measured and reported as parts per million (ppm) or parts per billion (ppb). A solution that contains 2 grams(0.071 ounces) of lead in 1 million grams (2,205 pounds) of water (1,000 liters, or 264.2 gallons) is a 2 ppm solution. A 1 ppb solution of calcium contains 1 gram (0.036 ounces) of calcium in 1 billion grams (2,205,000 pounds) of water. A concentration of 1 ppm is the same as 1 milligram(3.6 × 10−5 ounces) per liter.
While it is impractical to remove all impurities from water, the Safe Drinking Water Act, passed by the U.S. Congress in 1974, gives the Environmental Protection Agency (EPA) the authority to set limits for harmful contaminants in water. For each substance, the EPA establishes Maximum Contaminant Level Goals (MCLGs), levels at which the substance can be consumed over a long period of time with no known adverse effects. This level is defined as the amount of impurity that could be present in two liters of water drunk by a person weighing 70 kilograms (154 pounds), each day for seventy years, without ill effects. In addition, the EPA sets Maximum Contaminant Levels (MCLs) of substances for exposure at any single time. A single exposure to concentrations of pollutants below the MCL is considered to be harmless. The MCLG of lead is 0; continuous exposure to lead in any concentration is considered hazardous. The MCL of lead is 0.015 ppm. Both the MCLG and MCL of mercury are set at 0.002 ppm.
Specialized analytical equipment allows technicians to monitor pollutants. In the field, pH meters are used to measure acidity and turbidometers measure the presence of suspended solids. Samples taken to laboratories are analyzed by gas chromatography to determine the presence of organic
compounds such as vinyl chloride, by emission spectroscopy to detect heavy metals , and by high performance liquid chromatography (HPLC) to detect pesticide residues. Such instruments are capable of detecting as little as one part per trillion of pollutants in water.
For much of history, humans used waterways and bodies of water as waste dumps. When the human population was low, fewer people were exposed to the effects of pollution, and the sources were fewer and produced less pollution. During the Industrial Revolution of the nineteenth century, water pollution was recognized as a danger to public health.
Even early settlers were concerned with water quality. Two hundred years before laws were written to protect consumers from lead poisoning, Benjamin Franklin wrote of a family that suffered gastrointestinal pains after drinking water collected from their lead roof. During the trek west, members of wagon trains avoided drinking from stagnant pools, some of which contained large amounts of alkali.
As populations and production grew, industrial and household refuse accumulated, and it became clear that many discarded materials did not simply disappear, but were spread through the water table, absorbed by lower forms of life and passed up the food chain, causing deaths, birth defects, and mental problems. Now, many beaches are closed occasionally or permanently due to pollution, and at a time when populations of fish have decreased, many areas are unsafe for fishing. Water pollution represents an especially dangerous problem in developing nations, which have high populations and manufacturing facilities that do not meet safety standards.
The most dangerous forms of water pollutants include sewage, which frequently contains dangerous pathogenic organisms; oil and hydrocarbons; heavy metals; radioactive substances; pesticides and herbicides; and corrosive substances such as acids and bases.
In developed countries, few direct sources of water pollution should exist, but homeowners still discharge motor oil, antifreeze, pet waste, and paint into storm sewers, and small manufacturers sometimes ignore proper disposal procedures. In developing countries, businesses and households often discharge wastes directly into streams or ponds that are also used for water supplies. Many sources contaminate water supplies indirectly. Indirect sources of pollution include runoff of waste from feedlots or runoff of agricultural chemicals from farmlands; leaking oil from pipelines, wells, or platforms; and large amounts of sediment from streets and parking lots.
Most industrial operations are required to treat wastewater before discharging it into rivers. Wastes from feedlots are collected in lagoons, settled, collected, and used for fertilizer. Heavy metals and organic compounds from industry are often reclaimed from wastewater and recycled, decreasing manufacturing costs. Sewage from homes undergoes at least two stages of treatment. Primary treatment consists of sedimentation and dyeing of solids, which may be used as fertilizer. Secondary treatment consists of aeration of the remaining liquid, through a process of stirring, trickling over filters, and spraying; aerobic bacteria oxidize much of the remaining organic matter. Tertiary treatment, using antibacterial agents such as chlorine or ozone, may be used to produce effluent water that is safe for further use.
see also Neurotoxins; Toxicity; Water; Water Quality.
Dan M. Sullivan
MacKenzie, Susan Hill (1996). Integrated Resource Planning and Management: The Ecosystem Approach in the Great Lakes Basin. Washington, DC: Island Press.
Stanitski, Conrad L.; Eubanks, Lucy P.; Middlecamp, Catherine H.; and Pienta, Norman J. (2003). Chemistry in Context: Applying Chemistry to Society, 4th edition. Boston: McGraw-Hill.
"Water Pollution." Chemistry: Foundations and Applications. . Encyclopedia.com. (February 20, 2017). http://www.encyclopedia.com/science/news-wires-white-papers-and-books/water-pollution
"Water Pollution." Chemistry: Foundations and Applications. . Retrieved February 20, 2017 from Encyclopedia.com: http://www.encyclopedia.com/science/news-wires-white-papers-and-books/water-pollution
water pollution, contamination of water resources by harmful wastes; see also sewerage, water supply, pollution, and environmentalism.
In the United States industry is the greatest source of pollution, accounting for more than half the volume of all water pollution and for the most deadly pollutants. Some 370,000 manufacturing facilities use huge quantities of freshwater to carry away wastes of many kinds. The waste-bearing water, or effluent, is discharged into streams, lakes, or oceans, which in turn disperse the polluting substances. In its National Water Quality Inventory, reported to Congress in 1996, the U.S. Environmental Protection Agency concluded that approximately 40% of the nation's surveyed lakes, rivers, and estuaries were too polluted for such basic uses as drinking supply, fishing, and swimming. The pollutants include grit, asbestos, phosphates and nitrates, mercury, lead, caustic soda and other sodium compounds, sulfur and sulfuric acid, oils, and petrochemicals.
In addition, numerous manufacturing plants pour off undiluted corrosives, poisons, and other noxious byproducts. The construction industry discharges slurries of gypsum, cement, abrasives, metals, and poisonous solvents. Another pervasive group of contaminants entering food chains is the polychlorinated biphenyl (PCB) compounds, components of lubricants, plastic wrappers, and adhesives. In yet another instance of pollution, hot water discharged by factories and power plants causes so-called thermal pollution by increasing water temperatures. Such increases change the level of oxygen dissolved in a body of water, thereby disrupting the water's ecological balance, killing off some plant and animal species while encouraging the overgrowth of others.
Other Sources of Water Pollution
Towns and municipalities are also major sources of water pollution. In many public water systems, pollution exceeds safe levels. One reason for this is that much groundwater has been contaminated by wastes pumped underground for disposal or by seepage from surface water. When contamination reaches underground water tables, it is difficult to correct and spreads over wide areas. In addition, many U.S. communities discharge untreated or only partially treated sewage into the waterways, threatening the health of their own and neighboring populations.
Along with domestic wastes, sewage carries industrial contaminants and a growing tonnage of paper and plastic refuse (see solid waste). Although thorough sewage treatment would destroy most disease-causing bacteria, the problem of the spread of viruses and viral illness remains. Additionally, most sewage treatment does not remove phosphorus compounds, contributed principally by detergents, which cause eutrophication of lakes and ponds. Excreted drugs and household chemicals also are not removed by present municipal treatment facilites, and can be recycled into the drinking water supply.
Rain drainage is another major polluting agent because it carries such substances as highway debris (including oil and chemicals from automobile exhausts), sediments from highway and building construction, and acids and radioactive wastes from mining operations into freshwater systems as well as into the ocean. Also transported by rain runoff and by irrigation return-flow are animal wastes from farms and feedlots, a widespread source of pollutants impairing rivers and streams, groundwater, and even some coastal waters. Antibiotics, hormones, and other chemicals used to raise livestock are components of such animal wastes. Pesticide and fertilizer residues from farms also contribute to water pollution via rain drainage.
Large and small craft significantly pollute both inland and coastal waters by dumping their untreated sewage. Oil spilled accidentally or flushed from tankers and offshore rigs (900,000 metric tons annually) sullies beaches and smothers bird, fish, and plant life. In 1978 in one of the world's worst single instances of water pollution, the Amoco Cadiz broke in two on the coast of Brittany, France, and spilled 1.6 million barrels of oil, causing great environmental destruction. Oil well blowouts during offshore drilling, such as the 1979 Ixtoc 1 blowout in Gulf of Mexico off Mexico and the 2010 Deepwater Horizon blowout in the Gulf of Mexico off Louisiana, have also caused severe oil pollution. In addition to its direct damage to wildlife, oil takes up fat-soluble poisons like DDT, allowing them to be concentrated in organisms that ingest the oil-contaminated water; thus such poisons enter the food chains leading to sea mammals and people (see ecology).
Both DDT, which has been banned in the United States since 1972, and PCBs are manufactured in many parts of the world and are now widespread in the Atlantic and Pacific oceans. In addition, tarry oil residues are encountered throughout the Atlantic, as are styrofoam and other plastic rubbish. Plastic bits litter sections of the Pacific and Atlantic, accumulating in greater concentrations to form "garbage patches" where the currents are slack. Garbage, solid industrial wastes, and sludge formed in sewage treatment, all commonly dumped into oceans, are other marine pollutants found worldwide, especially along coastal areas.
Dangers of Water Pollution
Virtually all water pollutants are hazardous to humans as well as lesser species; sodium is implicated in cardiovascular disease, nitrates in blood disorders. Mercury and lead can cause nervous disorders. Some contaminants are carcinogens. DDT is toxic to humans and can alter chromosomes. PCBs cause liver and nerve damage, skin eruptions, vomiting, fever, diarrhea, and fetal abnormalities. Along many shores, shellfish can no longer be taken because of contamination by DDT, sewage, or industrial wastes.
Dysentery, salmonellosis, cryptosporidium, and hepatitis are among the maladies transmitted by sewage in drinking and bathing water. In the United States, beaches along both coasts, riverbanks, and lake shores have been ruined for bathers by industrial wastes, municipal sewage, and medical waste. Water pollution is an even greater problem in the Third World, where millions of people obtain water for drinking and sanitation from unprotected streams and ponds that are contaminated with human waste. This type of contamination has been estimated to cause more than 3 million deaths annually from diarrhea in Third World countries, most of them children.
Legislation and Control
The United States has enacted extensive federal legislation to fight water pollution. Laws include the Federal Water Pollution Control Act (1948), the Clean Water Act (1972), the Marine Protection, Research, and Sanctuaries Act (1972), the Safe Drinking Water Act (1974), and the Federal Insecticide, Fungicide, and Rodenticide Act, as amended in 1988. International cooperation is being promoted by the Inter-Governmental Maritime Consultive Organization (IMCO), a UN agency. Limitation of ocean dumping was proposed at the 80-nation London Conference of 1972, and in the same year 12 European nations meeting in Oslo adopted rules to regulate dumping in the North Atlantic. An international ban on ocean dumping in 1988 set further restrictions.
"water pollution." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. (February 20, 2017). http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/water-pollution
"water pollution." The Columbia Encyclopedia, 6th ed.. . Retrieved February 20, 2017 from Encyclopedia.com: http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/water-pollution
Water pollution exists when water is contaminated by impurities or its quality is otherwise adversely affected, for example, by solid matter or thermal discharges. Water pollution problems have a long history that can be traced to antiquity, and the attempts of communities to control such problems have an equally long track record. The nature of water pollution problems has changed over time, and their geographic scale has steadily increased, as has the scale of institutional solutions that have been adopted to control them. This entry explores the key changes in the nature and scale of water pollution and in the institutional solutions that have been adopted as a response to it.
Pollution of water by human wastes was a key public health problem when today’s developed countries urbanized in the 1800s. Urban life expectancies decreased because contaminated water supplies caused epidemics of cholera, typhoid fever, and other water-borne diseases and increased people’s susceptibility to all illnesses. These problems were initially local, when wells and ground water were used for water supplies, and communities responded to them with local public health and sanitation regulations. The construction of networked water supplies and sewer systems after the mid-1800s increased the scale of water pollution. Local regulations proved powerless when sources of pollution were increasingly outside the local jurisdiction. This situation gave rise to the first state and national water pollution policies, which successfully safeguarded public health but which largely failed to improve in-stream water quality.
The nature of water pollution changed in industrialized countries around the time of World War II (1939–1945) because the war effort and postwar reconstruction resulted in the rapid growth of industrial production and increased discharge of industrial effluents. New innovations such as organic pesticides and synthetic detergents also proved potent water pollutants. The decades after the war witnessed several widely publicized environmental disasters, including mercury pollution in Minamata, Japan, that caused “Minamata disease” in the 1950s; the Torrey Canyon (1967) and Amoco Cadiz (1978) supertanker disasters in Europe; and the Santa Barbara, California, oil spill in 1969. Furthermore, there was controversy over asbestos-containing discharges from Reserve Mining into Lake Superior in Silver Bay, Minnesota, in the 1970s; the leak of toxic chemicals from the Sandoz factory in Basel, Switzerland, in 1986; and the cyanide spill from a gold mine in Baia Mare, Romania, which polluted the Tisza and Danube rivers in 2000. More recently, in November 2005, an explosion in a chemical plant in Jilin, China, polluted the Songhua River with benzene and nitrobenzene.
Water pollution continues to be a public health problem in the developing world. Worldwide, one child out of six under five years of age dies of a diarrheal disease such as cholera, typhoid fever, dysentery, and gastroenteritis, which are caused by the contamination of water by human wastes. Moreover, weak enforcement or the nonexistence of environmental and safety regulations in developing countries means that agriculture, horticulture, and mining are major sources of toxic water pollutants such as pesticides and mercury. Such pollutants have caused grave public health consequences across the developing world, but particularly in severely polluted areas such as the Aral Sea region in Central Asia. In some places, such as in Bangladesh, naturally occurring arsenic pollutes certain layers of ground water on which many communities depend for their water supply.
Most developed countries have adopted water pollution policies that have reduced conventional water pollutants from point sources. Conventional pollutants include biochemical oxygen demand (BOD), total suspended solids (TSS), fecal coliform, oil and grease, and pH (acidity and alkalinity). Point sources include municipal sewage treatment plants, industrial establishments, and other facilities, which only contributed about half of all conventional pollutants in the United States when the Clean Water Act of 1972, with its focus on point sources, was adopted. Water pollution originating from nonpoint sources, such as agriculture, streets and roads, and storm sewers, was not originally controlled with the same level of effectiveness. National policies have also been less successful in reducing the amount of nonconventional pollutants, such as those of toxic chemicals. More recently, market-based instruments such as fertilizer, manure, and pesticide taxes have been used in many countries for controlling water pollution from nonpoint sources. Other market based instruments, particularly tradable effluent permits and sewerage charges, have increasingly been used also for controlling conventional water pollutants.
The incentives and capacity of states to control pollution from sources that lie outside their jurisdictions is limited, however. International environmental agreements have been negotiated to address this problem, including early agreements on the transportation of dangerous substances on the River Rhine in western Europe, which came into force between 1900 and 1902, and the Boundary Waters Treaty between the United States and Canada, which took effect in 1909. International agreements since 1970 have addressed, for example, the pollution of the marine environment by oil and dumping; the pollution of transboundary bodies of water such as the Baltic Sea, the North Sea, and the Mediterranean; the elimination of persistent organic compounds; and the international transport of hazardous materials and liability for damages caused by their transport. Some of these conventions, such as the 1992 Baltic Sea Convention, have been successful, while others have made little difference to the quality of the marine environment to date.
SEE ALSO Pollution; Pollution, Air; Pollution, Noise
Andrews, Richard N. L. 2006. Managing the Environment, Managing Ourselves: A History of American Environmental Policy. 2nd ed. New Haven, CT: Yale University Press.
Jamison, Dean T., et al., eds. 2006. Disease Control Priorities in Developing Countries. 2nd ed. New York: Oxford University Press.
Kirchner, Andree, ed. 2003. International Marine Environmental Law: Institutions, Implementation, and Innovations. New York and The Hague, Netherlands: Kluwer.
Paavola, Jouni. 2004. Law: Water and Air Pollution. In The Encyclopedia of World Environmental History, Vol. 2, eds. Shepard Krech III, J. R. McNeill, and Carolyn Merchant, 778–786. London and New York: Routledge.
Tarr, Joel A. 1996. The Search for the Ultimate Sink: Urban Pollution in Historical Perspective. Akron, OH: Akron University Press.
"Pollution, Water." International Encyclopedia of the Social Sciences. . Encyclopedia.com. (February 20, 2017). http://www.encyclopedia.com/social-sciences/applied-and-social-sciences-magazines/pollution-water
"Pollution, Water." International Encyclopedia of the Social Sciences. . Retrieved February 20, 2017 from Encyclopedia.com: http://www.encyclopedia.com/social-sciences/applied-and-social-sciences-magazines/pollution-water
Water Pollution and Biological Purification
Water pollution and biological purification
Water pollution may derive from several sources, including chemical pollutants from industry, runoff of chemicals used in agriculture, or debris from geological process, but the greatest source of pollution is organic waste. Although chemical pollutants may become diluted, they can also radically alter the ecosystem to allow the overproduction of certain forms of algae and bacteria that pollute the water with respect to its use by humans.
Once in the water, the growth of microorganisms can be exacerbated by environmental factors such as the water temperature and the chemical composition of the water. For example, runoff of fertilizers from suburban properties can infuse watercourses with nitrogen, potassium, and phosphorus. All these are desirable nutrients for bacterial growth.
With specific respect to microorganisms, water pollution refers to the presence in water of microbes that originated from the intestinal tract of humans and other warm-blooded animals. Water pollution can also refer to the presence of compounds that promote the growth of the microbes. The remediation of polluted water—the removal of the potentially harmful microorganisms or the reduction of their numbers to acceptable levels—represents the purification of water.
Microorganisms that reside in the intestinal tract find their way into fresh and marine water when feces contaminate the water. Examples of bacteria that can pollute water in this way are Escherichia coli, Salmonella, Shigella, and Vibrio cholerae. Warm-blooded animals other than humans can also contribute protozoan parasites to the water via their feces. The two prominent examples of health relevance to humans are Cryptosporidium parvum and Giardia lamblia. The latter two species are becoming more common. They are also resistant to chlorine, the most popular purification chemical.
Normally, the intestinal bacteria do not survive long in the inhospitable world of the water. However, if they are ingested while still living, they can cause maladies, ranging from inconvenient intestinal upset to life-threatening infections. An example of the latter is Escherichia coli O157:H7. Pollution of the water with this strain can cause severe intestinal damage, life-long damage to organs such as the kidney, and—especially in the young, elderly, and those whose immune systems are compromised—death.
There are several common ways in which microorganisms can pollute water. Runoff from agricultural establishments,
particularly where livestock is raised, is one route of contamination. Seasonal runoff can occur, especially in the springtime when rainfall is more pronounced.
Water purification seeks to convert the polluted water into water that is acceptable for drinking, for recreation, or for some other purpose. Techniques such as filtration and exposure to agents or chemicals that will kill the microorganisms in the water are common means of purification. The use of chlorination remains the most widely used purification option. Other approaches are the use of ultraviolet radiation, filters of extremely small pore size (such that even viruses are excluded), and the use of a chemical known as ozone . Depending on the situation and the intended use of the finished water, combinations of these techniques can be used.
Purification of drinking water aims to remove as many bacteria as possible, and eliminate those bacteria of intestinal origin. Recreational waters need not be pristine. But bacterial numbers need to be below whatever standard has been deemed permissible for the particular locale.
Another microbiological aspect of water pollution that has become recognized only within the past several years has been the presence in water of agents used to treat bacteria in other environments. For example, a number of disinfectant compounds are routinely employed in the cleaning of household surfaces. In the hospital, the use of antibiotics to kill bacteria is an everyday occurrence. Such materials have been detected in water both before and after municipal wastewater treatment . The health effect of these compounds is not known at the present time. However, looking at similar situations, the low concentration of such compounds might propogate the development of resistant bacterial populations.
Natural wetlands also contribute to the purification of water. Wetlands can serve as a depositional sump and provide biological filtering. Normal percolation through soil layers also provides a significant source of water purification.
See also Aquifer; Artesian; Drainage basins and drainage patterns; Estuary; Hydrologic cycle
"Water Pollution and Biological Purification." World of Earth Science. . Encyclopedia.com. (February 20, 2017). http://www.encyclopedia.com/science/encyclopedias-almanacs-transcripts-and-maps/water-pollution-and-biological-purification
"Water Pollution and Biological Purification." World of Earth Science. . Retrieved February 20, 2017 from Encyclopedia.com: http://www.encyclopedia.com/science/encyclopedias-almanacs-transcripts-and-maps/water-pollution-and-biological-purification
Water Pollution and Purification
Water pollution and purification
With respect to microorganisms , water pollution refers to the presence in water of microbes that originated from the intestinal tract of humans and other warm-blooded animals. Water pollution can also refer to the presence of compounds that promote the growth of the microbes. The remediation of polluted water—the removal of the potentially harmful microorganisms—or the reduction of their numbers to levels considered to be acceptable for whatever purpose the water is used, represents the purification of water.
Microorganisms that reside in the intestinal tract find their way into fresh and marine water when feces contaminate the water. Examples of bacteria that can pollute water in this way are Escherichia coli, Salmonella, Shigella, and Vibrio cholerae. Warm-blooded animals other than humans can also contribute protozoan parasites to the water via their feces. The two prominent examples of health relevance to humans are Cryptosporidium parvum and Giardia lamblia. The latter two species are becoming more prominent. They are also resistant to chlorine, the most popular purification chemical.
Normally, the intestinal bacteria do not survive long in the inhospitable world of the water. But, if they are ingested while still living, they can cause maladies, ranging from inconvenient intestinal upset to life-threatening infections. A prominent example of the latter is Escherichia coli O157:H7. Pollution of the water with this strain can cause severe intestinal damage, life long damage to organs such as the kidney and—especially in the young, elderly and those whose immune systems are compromised—death.
There are several common ways in which microorganisms can pollute water. Runoff from agricultural establishments, particularly where livestock is raised, is one route of contamination . Seasonal runoff can occur, especially in the springtime when rainfall is more pronounced. The feeding of birds (e.g., ducks) is now recognized as a contributing factor. For example, a large numbers of ducks that congregate can contribute large quantities of fecal material to localized ponds and lakes.
Once in the water, the growth of microorganisms can be exacerbated by environmental factors such as the water temperature, and by the chemical composition of the water. For example, runoff of fertilizers from suburban properties can infuse watercourses with nitrogen, potassium, and phosphorus. All these are desirable nutrients for bacterial growth .
Water purification seeks to convert the polluted water into water that is acceptable for drinking, for recreation, or for some other purpose. Techniques such as filtration and exposure to agents or chemicals that will kill the microorganisms in the water are common means of purification. The use of chlorination remains the most widely used purification option. Others approaches are the use of ultraviolet radiation, filters of extremely small pore size (such that even viruses are excluded), and the use of a chemical known as ozone. Depending on the situation and the intended use of the finished water, combinations of these techniques can be used.
Purification of drinking water aims to remove as many bacteria as possible, and to completely eliminate those bacteria of intestinal origin. Recreational waters need not be that pristine. But bacterial numbers need to be below whatever standard has been deemed permissible for the particular local.
Another microbiological aspect of water pollution that has become recognized only within the past several years has been the presence in water of agents used to treat bacteria in other environments. For example in the household a number of disinfectant compounds are routinely employed in the cleaning of household surfaces. In the hospital, the use of antibiotics to kill bacteria is an everyday occurrence. Such materials have been detected in water both before and after municipal wastewater treatment . The health effect of these compounds is not known at the present time. However, by analogy with other systems, the low concentration of such compounds might provide selective pressure for the development of resistant bacterial populations.
See also Chlorination; Waste water treatment; Water quality
"Water Pollution and Purification." World of Microbiology and Immunology. . Encyclopedia.com. (February 20, 2017). http://www.encyclopedia.com/science/encyclopedias-almanacs-transcripts-and-maps/water-pollution-and-purification
"Water Pollution and Purification." World of Microbiology and Immunology. . Retrieved February 20, 2017 from Encyclopedia.com: http://www.encyclopedia.com/science/encyclopedias-almanacs-transcripts-and-maps/water-pollution-and-purification
Water covers more than 70 percent of Earth's surface. It is essential to all life. Organisms can survive longer without food than without water. It is one of our most valuable resources.
Pollute means to make impure or unclean. In that sense, water pollution has always occurred as a natural phenomenon. Forest fires, storms, volcanoes, or a heavy leaf fall can contaminate a water body. However, these organic materials are broken down or biodegraded naturally.
Pollution as we know it began when humans started discarding waste including sewage and toxic chemicals. By the middle of the twentieth century, the extent of water pollution became apparent when Ohio's Cuyahoga River caught fire as a result of widespread oil pollution.
The Clean Water Act of 1972 and its subsequent amendments reduced surface-water pollution by prohibiting the dumping of toxic chemicals and medical waste, and by establishing a permitting system to reduce the direct discharge of pollutants. The Safe Drinking Water Act of 1974, later amended in 1987, set maximum allowable contaminant levels for drinking water and called for the regular monitoring of groundwater. And the Ocean Dumping Ban prohibited the marine disposal of sewage and industrial waste after 1991.
Water pollution is described as point source or nonpoint source. Point source means one can pinpoint and reduce pollution at its source. Point source pollution may come from an industrial discharge pipe, a wastewater treatment plant, or a capsized oil tanker. Nonpoint source pollution occurs when substances such as fertilizer, pesticides, and soil from erosion enter water bodies through rain runoff. Other pollutants include heavy metals such as mercury, salt, acid rain, silt, hot water, petroleum products, excess nutrients such as nitrogen and phosphorus, sewage, and animal waste. Since polluted water is extremely difficult and costly to clean up, prevention is by far the best approach to this form of environmental pollution.
see also Acid Rain; Agriculture; Clean Water Act; Cryptosporidiosis; Fish Kills; Hypoxia; Mercury; Nonpoint Source Pollution; PCBs (Polychlorinated Biphenyls); Rivers and Harbors Appropriations Act; Sedimentation; Water Pollution; Water Treatment; Wastewater Treatment.
epa clean water act. available from http://www.epa.gov/r5water/cwa.htm.
u.s. environmental protection agency. "ocean dumping ban act of 1988." available from http://www.epa.gov/history.
"Water Pollution." Pollution A to Z. . Encyclopedia.com. (February 20, 2017). http://www.encyclopedia.com/environment/educational-magazines/water-pollution
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