Water Pollution

Water pollutionFrom Wikipedia, the free encyclopediaJump to: navigation, search

Raw sewage and industrial waste in the New River as it passes from Mexicali to Calexico, California.

Water pollution is the contamination of water bodies (e.g. lakes, rivers, oceans, aquifers and groundwater). Water pollution occurs when pollutants are discharged directly or indirectly into water bodies without adequate treatment to remove harmful compounds.

Water pollution affects plants and organisms living in these bodies of water. In almost all cases the effect is damaging not only to individual species and populations, but also to the natural biological communities.

Contents

1 Introduction 2 Categories

o 2.1 Point sources o 2.2 Nonpoint sources

3 Groundwater pollution 4 Causes

o 4.1 Pathogens o 4.2 Chemical and other contaminants o 4.3 Thermal pollution

5 Transport and chemical reactions of water pollutants 6 Measurement

o 6.1 Sampling o 6.2 Physical testing o 6.3 Chemical testing

o 6.4 Biological testing 7 Control of pollution

o 7.1 Domestic sewage o 7.2 Industrial wastewater o 7.3 Agricultural wastewater o 7.4 Construction site stormwater o 7.5 Urban runoff (stormwater)

8 See also 9 References 10 External links

Introduction

Millions depend on the polluted Ganges river

Water pollution is a major global problem which requires ongoing evaluation and revision of water resource policy at all levels (international down to individual aquifers and wells). It has been suggested that it is the leading worldwide cause of deaths and diseases,[1][2] and that it accounts for the deaths of more than 14,000 people daily.[2] An estimated 700 million Indians have no access to a proper toilet, and 1,000 Indian children die of diarrheal sickness every day.[3] Some 90% of China's cities suffer from some degree of water pollution,[4] and nearly 500 million people lack access to safe drinking water.[5] In addition to the acute problems of water pollution in developing countries, developed countries continue to struggle with pollution problems as well. In the most recent national report on water quality in the United States, 45 percent of assessed stream miles, 47 percent of assessed lake acres, and 32 percent of assessed bays and estuarine square miles were classified as polluted.[6]

Water is typically referred to as polluted when it is impaired by anthropogenic contaminants and either does not support a human use, such as drinking water, and/or undergoes a marked shift in its ability to support its constituent biotic communities, such as fish. Natural phenomena such as volcanoes, algae blooms, storms, and earthquakes also cause major changes in water quality and the ecological status of water.

Categories

Surface water and groundwater have often been studied and managed as separate resources, although they are interrelated.[7] Surface water seeps through the soil and becomes groundwater. Conversely, groundwater can also feed surface water sources. Sources of surface water pollution are generally grouped into two categories based on their origin.

Point sources

Point source pollution – Shipyard – Rio de Janeiro.

Point source water pollution refers to contaminants that enter a waterway from a single, identifiable source, such as a pipe or ditch. Examples of sources in this category include discharges from a sewage treatment plant, a factory, or a city storm drain. The U.S. Clean Water Act (CWA) defines point source for regulatory enforcement purposes.[8] The CWA definition of point source was amended in 1987 to include municipal storm sewer systems, as well as industrial stormwater, such as from construction sites.[9]

Nonpoint sources

Nonpoint source pollution refers to diffuse contamination that does not originate from a single discrete source. NPS pollution is often the cumulative effect of small amounts of contaminants gathered from a large area. A common example is the leaching out of nitrogen compounds from fertilized agricultural lands. Nutrient runoff in stormwater from "sheet flow" over an agricultural field or a forest are also cited as examples of NPS pollution.

Contaminated storm water washed off of parking lots, roads and highways, called urban runoff, is sometimes included under the category of NPS pollution. However, this runoff is typically channeled into storm drain systems and discharged through pipes to local surface waters, and is a point source.

Groundwater pollution

See also: Hydrogeology

Interactions between groundwater and surface water are complex. Consequently, groundwater pollution, sometimes referred to as groundwater contamination, is not as easily classified as surface water pollution.[7] By its very nature, groundwater aquifers are susceptible to

contamination from sources that may not directly affect surface water bodies, and the distinction of point vs. non-point source may be irrelevant. A spill or ongoing releases of chemical or radionuclide contaminants into soil (located away from a surface water body) may not create point source or non-point source pollution, but can contaminate the aquifer below, defined as a toxin plume. The movement of the plume, called a plume front, may be analyzed through a hydrological transport model or groundwater model. Analysis of groundwater contamination may focus on the soil characteristics and site geology, hydrogeology, hydrology, and the nature of the contaminants.

Causes

The specific contaminants leading to pollution in water include a wide spectrum of chemicals, pathogens, and physical or sensory changes such as elevated temperature and discoloration. While many of the chemicals and substances that are regulated may be naturally occurring (calcium, sodium, iron, manganese, etc.) the concentration is often the key in determining what is a natural component of water, and what is a contaminant. High concentrations of naturally occurring substances can have negative impacts on aquatic flora and fauna.

Oxygen-depleting substances may be natural materials, such as plant matter (e.g. leaves and grass) as well as man-made chemicals. Other natural and anthropogenic substances may cause turbidity (cloudiness) which blocks light and disrupts plant growth, and clogs the gills of some fish species.[10]

Many of the chemical substances are toxic. Pathogens can produce waterborne diseases in either human or animal hosts.[11] Alteration of water's physical chemistry includes acidity (change in pH), electrical conductivity, temperature, and eutrophication. Eutrophication is an increase in the concentration of chemical nutrients in an ecosystem to an extent that increases in the primary productivity of the ecosystem. Depending on the degree of eutrophication, subsequent negative environmental effects such as anoxia (oxygen depletion) and severe reductions in water quality may occur, affecting fish and other animal populations.

Pathogens

A manhole cover unable to contain a sanitary sewer overflow.

Coliform bacteria are a commonly used bacterial indicator of water pollution, although not an actual cause of disease. Other microorganisms sometimes found in surface waters which have caused human health problems include:

Burkholderia pseudomallei Cryptosporidium parvum Giardia lamblia Salmonella Novovirus and other viruses Parasitic worms (helminths).[12][13]

High levels of pathogens may result from inadequately treated sewage discharges.[14] This can be caused by a sewage plant designed with less than secondary treatment (more typical in less-developed countries). In developed countries, older cities with aging infrastructure may have leaky sewage collection systems (pipes, pumps, valves), which can cause sanitary sewer overflows. Some cities also have combined sewers, which may discharge untreated sewage during rain storms.[15]

Pathogen discharges may also be caused by poorly managed livestock operations.

Chemical and other contaminants

Muddy river polluted by sediment. Photo courtesy of United States Geological Survey.

Contaminants may include organic and inorganic substances.

Organic water pollutants include:

Detergents Disinfection by-products found in chemically disinfected drinking water, such as

chloroform Food processing waste, which can include oxygen-demanding substances, fats and grease Insecticides and herbicides, a huge range of organohalides and other chemical

compounds Petroleum hydrocarbons, including fuels (gasoline, diesel fuel, jet fuels, and fuel oil) and

lubricants (motor oil), and fuel combustion byproducts, from stormwater runoff [16] Tree and bush debris from logging operations

Volatile organic compounds (VOCs), such as industrial solvents, from improper storage. Chlorinated solvents , which are dense non-aqueous phase liquids (DNAPLs), may fall to

the bottom of reservoirs, since they don't mix well with water and are denser. o Polychlorinated biphenyl (PCBs)o Trichloroethylene

Perchlorate Various chemical compounds found in personal hygiene and cosmetic products.

A garbage collection boom in an urban-area stream in Auckland, New Zealand.

Inorganic water pollutants include:

Acidity caused by industrial discharges (especially sulfur dioxide from power plants) Ammonia from food processing waste Chemical waste as industrial by-products Fertilizers containing nutrients--nitrates and phosphates—which are found in stormwater

runoff from agriculture, as well as commercial and residential use[16]

Heavy metals from motor vehicles (via urban stormwater runoff)[16][17] and acid mine drainage

Silt (sediment) in runoff from construction sites, logging, slash and burn practices or land clearing sites.

Macroscopic Pollution in Parks Milwaukee, WI

Macroscopic pollution—large visible items polluting the water—may be termed "floatables" in an urban stormwater context, or marine debris when found on the open seas, and can include such items as:

Trash or garbage (e.g. paper, plastic, or food waste) discarded by people on the ground, along with accidental or intentional dumping of rubbish, that are washed by rainfall into storm drains and eventually discharged into surface waters

Nurdles , small ubiquitous waterborne plastic pellets Shipwrecks , large derelict ships.

Thermal pollution

Main article: Thermal pollution

Thermal pollution is the rise or fall in the temperature of a natural body of water caused by human influence. Thermal pollution, unlike chemical pollution, results in a change in the physical properties of water. A common cause of thermal pollution is the use of water as a coolant by power plants and industrial manufacturers. Elevated water temperatures decreases oxygen levels (which can kill fish) and affects ecosystem composition, such as invasion by new thermophilic species. Urban runoff may also elevate temperature in surface waters.

Thermal pollution can also be caused by the release of very cold water from the base of reservoirs into warmer rivers.

Transport and chemical reactions of water pollutants

See also: Marine pollution

Most water pollutants are eventually carried by rivers into the oceans. In some areas of the world the influence can be traced hundred miles from the mouth by studies using hydrology transport models. Advanced computer models such as SWMM or the DSSAM Model have been used in many locations worldwide to examine the fate of pollutants in aquatic systems. Indicator filter feeding species such as copepods have also been 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 planktonic tissue. The Hudson discharge flows south along the coast due to coriolis force. Further south then are areas of oxygen depletion, caused by chemicals using up oxygen and by algae blooms, caused by excess nutrients from algal cell death and decomposition. Fish and shellfish kills have been reported, because toxins climb the food chain after small fish consume copepods, then large fish eat smaller fish, etc. Each successive step up the food chain causes a stepwise concentration of pollutants such as heavy metals (e.g. mercury) and persistent organic pollutants such as DDT. This is known as biomagnification, which is occasionally used interchangeably with bioaccumulation.

A polluted river draining an abandoned copper mine on Anglesey

Large gyres (vortexes) in the oceans trap floating plastic debris. The North Pacific Gyre for example has collected the so-called "Great Pacific Garbage Patch" that is now estimated at 100 times the size of Texas. Many of these long-lasting pieces wind up in the stomachs of marine birds and animals. This results in obstruction of digestive pathways which leads to reduced appetite or even starvation.

Many chemicals undergo reactive decay or chemically change especially over long periods of time in groundwater reservoirs. A noteworthy class of such chemicals is the chlorinated hydrocarbons such as trichloroethylene (used in industrial metal degreasing and electronics manufacturing) and tetrachloroethylene used in the dry cleaning industry (note latest advances in liquid carbon dioxide in dry cleaning that avoids all use of chemicals). Both of these chemicals, which are carcinogens themselves, undergo partial decomposition reactions, leading to new hazardous chemicals (including dichloroethylene and vinyl chloride).

Groundwater pollution is much more difficult to abate than surface pollution because groundwater can move great distances through unseen aquifers. Non-porous aquifers such as clays partially purify water of bacteria by simple filtration (adsorption and absorption), dilution, and, in some cases, chemical reactions and biological activity: however, in some cases, the pollutants merely transform to soil contaminants. Groundwater that moves through cracks and caverns 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 sinkholes as dumps in areas of Karst topography.

There are a variety of secondary effects stemming not from the original pollutant, but a derivative condition. An example is silt-bearing surface runoff, which can inhibit the penetration of sunlight through the water column, hampering photosynthesis in aquatic plants.

Measurement

Environmental Scientists preparing water autosamplers.

Water pollution may be analyzed through several broad categories of methods: physical, chemical and biological. Most involve collection of samples, followed by specialized analytical tests. Some methods may be conducted in situ, without sampling, such as temperature. Government agencies and research organizations have published standardized, validated analytical test methods to facilitate the comparability of results from disparate testing events.[18]

Sampling

Sampling of water for physical or chemical testing can be done by several methods, depending on the accuracy needed and the characteristics of the contaminant. Many contamination events are sharply restricted in time, most commonly in association with rain events. For this reason "grab" samples are often inadequate for fully quantifying contaminant levels. Scientists gathering this type of data often employ auto-sampler devices that pump increments of water at either time or discharge intervals.

Sampling for biological testing involves collection of plants and/or animals from the surface water body. Depending on the type of assessment, the organisms may be identified for biosurveys (population counts) and returned to the water body, or they may be dissected for bioassays to determine toxicity.

Further information: Water quality#Sampling and Measurement

Physical testing

Common physical tests of water include temperature, solids concentrations (e.g., total suspended solids (TSS)) and turbidity.

Chemical testing

See also: water chemistry analysis and environmental chemistry

Water samples may be examined using the principles of analytical chemistry. Many published test methods are available for both organic and inorganic compounds. Frequently used methods include pH, biochemical oxygen demand (BOD),[19]:102 chemical oxygen demand (COD),[19]:104

nutrients (nitrate and phosphorus compounds), metals (including copper, zinc, cadmium, lead and mercury), oil and grease, total petroleum hydrocarbons (TPH), and pesticides.

Biological testing

Main article: Bioindicator

Biological testing involves the use of plant, animal, and/or microbial indicators to monitor the health of an aquatic ecosystem.

For microbial testing of drinking water, see Bacteriological water analysis.

Control of pollution

Domestic sewage

Main article: Sewage treatment

Deer Island Waste Water Treatment Plant serving Boston, Massachusetts and vicinity.

Domestic sewage is 99.9 percent pure water, while the other 0.1 percent are pollutants. Although found in low concentrations, these pollutants pose risk on a large scale.[20] In urban areas, domestic sewage is typically treated by centralized sewage treatment plants. In the U.S., most of these plants are operated by local government agencies, frequently referred to as publicly owned treatment works (POTW). Municipal treatment plants are designed to control conventional pollutants: BOD and suspended solids. Well-designed and operated systems (i.e., secondary treatment or better) can remove 90 percent or more of these pollutants. Some plants have additional sub-systems to treat nutrients and pathogens. Most municipal plants are not designed to treat toxic pollutants found in industrial wastewater.[21]

Cities with sanitary sewer overflows or combined sewer overflows employ one or more engineering approaches to reduce discharges of untreated sewage, including:

utilizing a green infrastructure approach to improve stormwater management capacity throughout the system, and reduce the hydraulic overloading of the treatment plant[22]

repair and replacement of leaking and malfunctioning equipment[15]

increasing overall hydraulic capacity of the sewage collection system (often a very expensive option).

A household or business not served by a municipal treatment plant may have an individual septic tank, which treats the wastewater on site and discharges into the soil. Alternatively, domestic wastewater may be sent to a nearby privately owned treatment system (e.g. in a rural community).

Industrial wastewater

Main article: Industrial wastewater treatment

Dissolved air flotation system for treating industrial wastewater.

Some industrial facilities generate ordinary domestic sewage that can be treated by municipal facilities. Industries that generate wastewater with high concentrations of conventional pollutants (e.g. oil and grease), toxic pollutants (e.g. heavy metals, volatile organic compounds) or other nonconventional pollutants such as ammonia, need specialized treatment systems. Some of these facilities can install a pre-treatment system to remove the toxic components, and then send the partially treated wastewater to the municipal system. Industries generating large volumes of wastewater typically operate their own complete on-site treatment systems.

Some industries have been successful at redesigning their manufacturing processes to reduce or eliminate pollutants, through a process called pollution prevention.

Heated water generated by power plants or manufacturing plants may be controlled with:

cooling ponds , man-made bodies of water designed for cooling by evaporation, convection, and radiation

cooling towers , which transfer waste heat to the atmosphere through evaporation and/or heat transfer

cogeneration , a process where waste heat is recycled for domestic and/or industrial heating purposes.[23]

Agricultural wastewater

Main article: Agricultural wastewater treatment

Riparian buffer lining a creek in Iowa

Nonpoint source controlsSediment (loose soil) washed off fields is the largest source of agricultural pollution in the United States.[10] Farmers may utilize erosion controls to reduce runoff flows and retain soil on their fields. Common techniques include contour plowing, crop mulching, crop rotation, planting perennial crops and installing riparian buffers.[24][25]:pp. 4-95–4-96

Nutrients (nitrogen and phosphorus) are typically applied to farmland as commercial fertilizer; animal manure; or spraying of municipal or industrial wastewater (effluent) or sludge. Nutrients may also enter runoff from crop residues, irrigation water, wildlife, and atmospheric deposition.[25]:p. 2-9 Farmers can develop and implement nutrient management plans to reduce excess application of nutrients.[24][25]:pp. 4-37–4-38

To minimize pesticide impacts, farmers may use Integrated Pest Management (IPM) techniques (which can include biological pest control) to maintain control over pests, reduce reliance on chemical pesticides, and protect water quality.[26]

Feedlot in the United States

Point source wastewater treatmentFarms with large livestock and poultry operations, such as factory farms, are called concentrated animal feeding operations or feedlots in the US and are being subject to increasing government

regulation.[27][28] Animal slurries are usually treated by containment in anaerobic lagoons before disposal by spray or trickle application to grassland. Constructed wetlands are sometimes used to facilitate treatment of animal wastes. Some animal slurries are treated by mixing with straw and composted at high temperature to produce a bacteriologically sterile and friable manure for soil improvement.

Construction site stormwater

Silt fence installed on a construction site.

Sediment from construction sites is managed by installation of:

erosion controls , such as mulching and hydroseeding, and sediment controls , such as sediment basins and silt fences.[29]

Discharge of toxic chemicals such as motor fuels and concrete washout is prevented by use of:

spill prevention and control plans, and specially designed containers (e.g. for concrete washout) and structures such as overflow

controls and diversion berms.[30]

Urban runoff (stormwater)

Main article: Urban runoffSee also: Green infrastructure

Retention basin for controlling urban runoff

Effective control of urban runoff involves reducing the velocity and flow of stormwater, as well as reducing pollutant discharges. Local governments use a variety of stormwater management techniques to reduce the effects of urban runoff. These techniques, called best management practices (BMPs) in the U.S., may focus on water quantity control, while others focus on improving water quality, and some perform both functions.[31]

Pollution prevention practices include low-impact development techniques, installation of green roofs and improved chemical handling (e.g. management of motor fuels & oil, fertilizers and pesticides).[32] Runoff mitigation systems include infiltration basins, bioretention systems, constructed wetlands, retention basins and similar devices.[33][34]

Thermal pollution from runoff can be controlled by stormwater management facilities that absorb the runoff or direct it into groundwater, such as bioretention systems and infiltration basins. Retention basins tend to be less effective at reducing temperature, as the water may be heated by the sun before being discharged to a receiving stream.[31]:p. 5-58

See also

Water portal

Sustainable development portal

Environment portal

Book: Pollution

Aquatic toxicology Cultural eutrophication Interprovincial Cooperatives v. The Queen (Supreme Court of Canada) Oil spill Paper pollution Peak water (water resources planning concept) Trophic state index (water quality indicator for lakes) Watershed Central Streeter-Phelps equation

References

1. ̂ Pink, Daniel H. (April 19, 2006). "Investing in Tomorrow's Liquid Gold". Yahoo.2. ^ a b West, Larry (March 26, 2006). "World Water Day: A Billion People Worldwide

Lack Safe Drinking Water". About.3. ̂ "A special report on India: Creaking, groaning: Infrastructure is India’s biggest

handicap". The Economist. December 11, 2008.

4. ̂ "China says water pollution so severe that cities could lack safe supplies". Chinadaily.com.cn. June 7, 2005.

5. ̂ "As China Roars, Pollution Reaches Deadly Extremes". The New York Times. August 26, 2007.

6. ̂ United States Environmental Protection Agency (EPA). Washington, DC. "The National Water Quality Inventory: Report to Congress for the 2002 Reporting Cycle   – A Profile." October 2007. Fact Sheet No. EPA 841-F-07-003.

7. ^ a b United States Geological Survey (USGS), Denver, CO (1998). "Ground Water and Surface Water: A Single Resource." Circular 1139.

8. ̂ Clean Water Act, section 502(14), 33 U.S.C. §   1362 (14).9. ̂ CWA section 402(p), 33 U.S.C. §   1342(p) 10. ^ a b EPA. "Protecting Water Quality from Agricultural Runoff." Fact Sheet No. EPA-

841-F-05-001. March 2005.11. ̂ C. Michael Hogan (2010). "Water pollution.". Encyclopedia of Earth. Topic ed. Mark

McGinley; ed. in chief C. Cleveland. National Council on Science and the Environment, Washington, DC.

12. ̂ USGS. Reston, VA. "A Primer on Water Quality." FS-027-01. March 2001.13. ̂ Schueler, Thomas R. "Microbes and Urban Watersheds: Concentrations, Sources, &

Pathways." Reprinted in The Practice of Watershed Protection. 2000. Center for Watershed Protection. Ellicott City, MD.

14. ̂ EPA. “Illness Related to Sewage in Water.” Accessed February 20, 2009.15. ^ a b EPA. "Report to Congress: Impacts and Control of CSOs and SSOs." August 2004.

Document No. EPA-833-R-04-001.16. ^ a b c G. Allen Burton, Jr., Robert Pitt (2001). Stormwater Effects Handbook: A Toolbox

for Watershed Managers, Scientists, and Engineers. New York: CRC/Lewis Publishers. ISBN 0-87371-924-7. Chapter 2.

17. ̂ Schueler, Thomas R. "Cars Are Leading Source of Metal Loads in California." Reprinted in The Practice of Watershed Protection. 2000. Center for Watershed Protection. Ellicott City, MD.

18. ̂ For example, see Clescerl, Leonore S.(Editor), Greenberg, Arnold E.(Editor), Eaton, Andrew D. (Editor). Standard Methods for the Examination of Water and Wastewater (20th ed.) American Public Health Association, Washington, DC. ISBN 0-87553-235-7. This publication is also available on CD-ROM and online by subscription.

19. ^ a b Newton, David (2008). Chemistry of the Environment. Checkmark Books. ISBN 0-8160-7747-9.

20. ̂ "Environmental works: types of sewage. Encyclopaedia Britannica Online. N.p., 2009. Web. October 9, 2009. <http://www.search.eb.com/eb/article-72342>

21. ̂ EPA (2004)."Primer for Municipal Wastewater Treatment Systems." Document No. EPA 832-R-04-001.

22. ̂ EPA. "Green Infrastructure Case Studies: Philadelphia." December 9, 2008.23. ̂ EPA (1997). Profile of the Fossil Fuel Electric Power Generation Industry (Report).

Document No. EPA/310-R-97-007. p. 2424. ^ a b U.S. Natural Resources Conservation Service (NRCS). Washington, DC. "National

Conservation Practice Standards." National Handbook of Conservation Practices. Accessed March 28, 2009.

25. ^ a b c EPA. "National Management Measures to Control Nonpoint Source Pollution from Agriculture." July 2003. Document No. EPA-841-B-03-004.

26. ̂ EPA. "Integrated Pest Management Principles." March 13, 2008.27. ̂ EPA. "Animal Feeding Operations." December 15, 2008.28. ̂ Iowa Department of Natural Resources. Des Moines, IA. "Animal Feeding Operations

in Iowa." Accessed March 5, 2009.29. ̂ Tennessee Department of Environment and Conservation. Nashville, TN."Tennessee

Erosion and Sediment Control Handbook." 2002.30. ̂ EPA (2006). "Construction Site Stormwater Runoff Control." National Menu of

Stormwater Best Management Practices.31. ^ a b EPA (1999)."Preliminary Data Summary of Urban Storm Water Best Management

Practices." Chapter 5. Document No. EPA-821-R-99-012.32. ̂ EPA. "Fact Sheet: Low Impact Development and Other Green Design Strategies."

October 9, 2008.33. ̂ California Stormwater Quality Association. Menlo Park, CA. "Stormwater Best

Management Practice (BMP) Handbooks." 2003.34. ̂ New Jersey Department of Environmental Protection. Trenton, NJ. "New Jersey

Stormwater Best Management Practices Manual." April 2004.

External links

Wikimedia Commons has media related to: Water pollution

Overview Information

"Troubled Waters" - video from "Strange Days on Planet Earth" by National Geographic & PBS (US)

"Issues: Water" – Guides, news and reports from US Natural Resources Defense Council "Groundwater pollution" – U.S. Geological Survey of groundwater contamination

Analytical Tools and Other Specialized Resources

Water pollution advice for businesses from the Environment Agency EUGRIS – portal for Soil and Water Management in Europe Causal Analysis/Diagnosis Decision Information System (CADDIS) - EPA guide for

identifying pollution problems; stressor identification Ecotoxicology and Models - Eawag: Swiss Federal Institute of Aquatic Science &

Technology

[show]

v t

e

Pollution

[show]

v t e

Marine pollution

[show]

v t e

WaterView page ratingsRate this pageWhat's this?TrustworthyObjectiveCompleteWell-written

I am highly knowledgeable about this topic (optional) Categories:

Aquatic ecology Aquifers Environmental science Water and the environment Water chemistry Water pollution Water supply

Navigation menu

Create account Log in

Article Talk

Read

View source View history

Main page Contents Featured content Current events Random article Donate to Wikipedia

Interaction

Help About Wikipedia Community portal Recent changes Contact Wikipedia

Toolbox

Print/export

Languages

Afrikaans العربية বাং��লা� Català Česky Deutsch Eesti Español Esperanto Euskara فارسی Français Galego ગુ�જરા�તી� 한국어 हि�न्दी� Bahasa Indonesia Italiano עברית

ಕನ್ನ�ಡ Қазақша Magyar Македонски Bahasa Melayu Nederlands 日本語 Norsk (bokmål) Polski Português Русский सं�स्कृ� तम्� Српски / srpski Suomi Svenska தமி�ழ் తెలు�గు� ไทย Türkçe Tiếng Việt Walon 中文

This page was last modified on 20 January 2013 at 03:54. Text is available under the Creative Commons Attribution-ShareAlike License;

additional terms may apply. See Terms of Use for details.Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization.

Contact us

Privacy policy About Wikipedia Disclaimers Mobile view

SOIL POLLUTION Definition: Soil pollution is defined as the build-up in soils of persistent toxic

compounds, chemicals, salts,

radioactive materials, or disease causing agents, which have adverse effects on plant growth and animal

health. Soil is the thin layer of organic and inorganic materials that covers the

Earth's rocky surface. The organic portion, which is derived from the decayed remains of

plants and animals, is concentrated in the dark uppermost topsoil. The inorganic portion made up of rock

fragments, was formed over thousands of years by physical and chemical weathering of bedrock.

Productive soils are necessary for agriculture to supply the world with sufficient food.

There are many different ways that soil can become polluted, such as:

• Seepage from a landfill • Discharge of industrial waste into the soil • Percolation of contaminated water into the soil • Rupture of underground storage tanks • Excess application of pesticides, herbicides or fertilizer • Solid waste seepage The most common chemicals involved in causing soil pollution are: • Petroleum hydrocarbons • Heavy metals • Pesticides • Solvents

Types of Soil Pollution • Agricultural Soil Pollution i) pollution of surface soil ii) pollution of underground soil • Soil pollution by industrial effluents and solid wastes i) pollution of surface soil ii) disturbances in soil profile • Pollution due to urban activities i) pollution of surface soil ii) pollution of underground soil

Causes of Soil Pollution Soil pollution is caused by the presence of man-made chemicals or

other alteration in the natural soil environment. This type of contamination typically arises from the

rupture of underground storage links, application of pesticides, percolation of contaminated surface

water to subsurface strata, oil and fuel dumping, leaching of wastes from landfills or direct discharge of

industrial wastes to the soil. The

most common chemicals involved are petroleum hydrocarbons, solvents, pesticides, lead and other

heavy metals. This occurrence of this phenomenon is correlated with the degree of industrialization and

intensities of chemical usage. A soil pollutant is any factor which deteriorates the quality, texture and

mineral content of the soil or which disturbs the biological balance of the organisms in the

soil. Pollution in soil has adverse effect on plant growth. Pollution in soil is associated with • Indiscriminate use of fertilizers • Indiscriminate use of pesticides, insecticides and herbicides • Dumping of large quantities of solid waste • Deforestation and soil erosion Indiscriminate use of fertilizers Soil nutrients are important for plant growth and development. Plants

obtain carbon, hydrogen and oxygen from air and water. But other necessary nutrients like

nitrogen, phosphorus, potassium, calcium, magnesium, sulfur and more must be obtained from the soil.

Farmers generally use fertilizers to correct soil deficiencies. Fertilizers contaminate the soil with

impurities, which come from the raw materials used for their manufacture. Mixed fertilizers often contain

ammonium nitrate (NH4NO3), phosphorus as P2O5, and potassium as K2O. For instance, As, Pb and

Cd present in traces in rock phosphate mineral get transferred to super phosphate fertilizer. Since

the metals are not degradable, their accumulation in the soil above their toxic levels due to excessive

use of phosphate fertilizers, becomes an indestructible poison for crops. The over use of NPK fertilizers reduce quantity of vegetables and crops

grown on soil over the years. It also reduces the protein content of wheat, maize, grams, etc.,

grown on that soil. The carbohydrate quality of such crops also gets degraded. Excess

potassium content in soil decreases Vitamin C and carotene content in vegetables and fruits. The

vegetables and fruits grown on overfertilized soil are more prone to attacks by insects and disease. Indiscriminate use of pesticides, insecticides and

herbicides

Plants on which we depend for food are under attack from insects, fungi, bacteria, viruses,

rodents and other animals, and must compete with weeds for nutrients. To kill unwanted populations

living in or on their crops, farmers use pesticides. The first widespread insecticide use began at the end

of World War II and included DDT (dichlorodiphenyltrichloroethane) and gammaxene. Insects soon

became resistant to DDT and as the chemical did not decompose readily, it persisted in the

environment. Since it was soluble in fat rather than water, it biomagnified up the food chain and

disrupted calcium metabolism in birds, causing eggshells to be thin and fragile. As a result, large birds

of prey such as the brown pelican, ospreys, falcons and eagles became endangered. DDT has been now

been banned in most western countries. Ironically many of them including USA, still produce DDT for

export to other developing nations whose needs outweigh the problems caused by it.

The most important pesticides are DDT, BHC, chlorinated hydrocarbons, organophosphates,

aldrin, malathion, dieldrin, furodan, etc. The remnants of such pesticides used on pests may get

adsorbed by the soil particles, which then contaminate root crops grown in that soil. The consumption

of such crops causes the pesticides remnants to enter human biological systems, affecting them

adversely. An infamous herbicide used as a defoliant in the Vietnam War called

Agent Orange (dioxin), was eventually banned. Soldiers' cancer cases, skin conditions and

infertility have been linked to exposure to Agent Orange. Pesticides not only bring toxic effect on human and animals but also

decrease the fertility of the soil. Some of the pesticides are quite stable and their bio- degradation

may take weeks and even months. Pesticide problems such as resistance, resurgence, and heath effects

have caused scientists to seek alternatives. Pheromones and hormones to attract or repel

insects and using natural enemies or sterilization by radiation have been suggested. Dumping of solid wastes

In general, solid waste includes garbage, domestic refuse and discarded solid materials such as

those from commercial, industrial and agricultural operations. They contain increasing amounts of

paper, cardboards, plastics, glass, old construction material, packaging material and toxic or otherwise

hazardous substances. Since a significant amount of urban solid waste tends to be paper and food

waste, the majority is recyclable or biodegradable in landfills. Similarly, most agricultural waste is

recycled and mining waste is left on site. The portion of solid waste that is hazardous such as oils, battery

metals, heavy metals from smelting industries and organic solvents are the ones we have to pay

particular attention to. These can in the long run, get deposited to the soils of the surrounding area and

pollute them by altering their chemical and biological properties. They also contaminate drinking

water aquifer sources. More than 90% of hazardous waste is produced by chemical, petroleum and

metal-related industries and small businesses such as dry cleaners and gas stations contribute as well. Solid Waste disposal was brought to the forefront of public attention by

the notorious Love Canal case in USA in 1978. Toxic chemicals leached from oozing

storage drums into the soil underneath homes, causing an unusually large number of birth

defects, cancers and respiratory, nervous and kidney diseases. Deforestation Soil Erosion occurs when the weathered soil particles are dislodged and

carried away by wind or water. Deforestation, agricultural development, temperature

extremes, precipitation including acid rain, and human activities contribute to this erosion. Humans speed up

this process by construction, mining, cutting of timber, over cropping and overgrazing. It results in

floods and cause soil erosion. Forests and grasslands are an excellent binding material that keeps

the soil intact and healthy. They support many habitats and ecosystems, which provide

innumerable feeding pathways or food chains to all species. Their loss would threaten food chains and the

survival of many species. During the past few years quite a lot of vast green land has been converted

into deserts. The precious rain

forest habitats of South America, tropical Asia and Africa are coming under pressure of population

growth and development (especially timber, construction and agriculture). Many scientists believe that

a wealth of medicinal substances including a cure for cancer and aids, lie in these forests. Deforestation

is slowly destroying the most productive flora and fauna areas in the world, which also form vast tracts

of a very valuable sink for CO2.

Pollution Due to Urbanisation Pollution of surface soils Urban activities generate large quantities of city wastes including

several Biodegradable materials (like vegetables, animal wastes, papers, wooden pieces,

carcasses, plant twigs, leaves, cloth wastes as well as sweepings) and many non-biodegradable materials

(such as plastic bags, plastic bottles, plastic wastes, glass bottles, glass pieces, stone / cement

pieces). On a rough estimate Indian cities are producing solid city wastes to the tune of 50,000 - 80,000

metric tons every day. If left uncollected and decomposed, they are a cause of several problems

such as • Clogging of drains: Causing serious drainage problems including the

burst / leakage of drainage lines leading to health problems. • Barrier to movement of water: Solid wastes have seriously damaged

the normal movement of water thus creating problem of inundation, damage to foundation of

buildings as well as public health hazards. • Foul smell: Generated by dumping the wastes at a place. • Increased microbial activities: Microbial decomposition of organic

wastes generate large quantities of methane besides many chemicals to pollute the soil and

water flowing on its surface • When such solid wastes are hospital wastes they create many health

problems: As they may have dangerous pathogen within them besides dangerous medicines,

injections.

Pollution of Underground Soil Underground soil in cities is likely to be polluted by • Chemicals released by industrial wastes and industrial wastes • Decomposed and partially decomposed materials of sanitary wastes

Many dangerous chemicals like cadmium, chromium, lead, arsenic, selenium products are likely

to be deposited in underground soil. Similarly underground soil polluted by sanitary wastes generate

many harmful chemicals.These can damage the normal activities and ecological balance in the

underground soil Causes in brief: • Polluted water discharged from factories • Runoff from pollutants (paint, chemicals, rotting organic material)

leaching out of landfill • Oil and petroleum leaks from vehicles washed off the road by the rain

into the surrounding habitat • Chemical fertilizer runoff from farms and crops • Acid rain (fumes from factories mixing with rain) • Sewage discharged into rivers instead of being treated properly • Over application of pesticides and fertilizers • Purposeful injection into groundwater as a disposal method • Interconnections between aquifers during drilling (poor technique) • Septic tank seepage • Lagoon seepage • Sanitary/hazardous landfill seepage • Cemeteries • Scrap yards (waste oil and chemical drainage) • Leaks from sanitary sewers

Effects of Soil Pollution Agricultural • Reduced soil fertility • Reduced nitrogen fixation • Increased erodibility • Larger loss of soil and nutrients • Deposition of silt in tanks and reservoirs • Reduced crop yield • Imbalance in soil fauna and flora

Industrial • Dangerous chemicals entering underground water • Ecological imbalance • Release of pollutant gases • Release of radioactive rays causing health problems • Increased salinity • Reduced vegetation

Urban • Clogging of drains

• Inundation of areas • Public health problems • Pollution of drinking water sources • Foul smell and release of gases • Waste management problems

Environmental Long Term Effects of Soil Pollution

When it comes to the environment itself, the toll of contaminated soil is even more dire. Soil

that has been contaminated should no longer be used to grow food, because the chemicals can leech

into the food and harm people who eat it. If contaminated soil is used to grow food, the land will usually produce

lower yields than it would if it were not contaminated. This, in turn, can cause even more

harm because a lack of plants on the soil will cause more erosion, spreading the contaminants onto land

that might not have been tainted before. In addition, the pollutants will change the makeup of the soil and the

types of microorganisms that will live in it. If certain organisms die off in the area, the larger

predator animals will also have to move away or die because they've lost their food supply. Thus it's

possible for soil pollution to change whole ecosystems Effects of soil pollution in brief: • pollution runs off into rivers and kills the fish, plants and other

aquatic life • crops and fodder grown on polluted soil may pass the pollutants on

to the consumers • polluted soil may no longer grow crops and fodder • Soil structure is damaged (clay ionic structure impaired) • corrosion of foundations and pipelines • impairs soil stability • may release vapours and hydrocarbon into buildings and cellars • may create toxic dusts • may poison children playing in the area

Control of soil pollution The following steps have been suggested to control soil pollution. To

help prevent soil erosion, we can limit construction in sensitive area. In general we would need

less fertilizer and fewer pesticides

if we could all adopt the three R's: Reduce, Reuse, and Recycle. This would give us less solid waste.

Reducing chemical fertilizer and pesticide use Applying bio-fertilizers and manures can reduce chemical fertilizer and

pesticide use. Biological methods of pest control can also reduce the use of

pesticides and thereby minimize soil pollution. Reusing of materials Materials such as glass containers, plastic bags, paper, cloth etc. can

be reused at domestic levels rather than being disposed, reducing solid waste pollution. Recycling and recovery of materials This is a reasonable solution for reducing soil pollution. Materials such

as paper, some kinds of plastics and glass can and are being recycled. This decreases the

volume of refuse and helps in the conservation of natural resources. For example, recovery of one tonne

of paper can save 17 trees. Reforesting Control of land loss and soil erosion can be attempted through

restoring forest and grass cover to check wastelands, soil erosion and floods. Crop rotation or mixed

cropping can improve the fertility of the land. Solid waste treatment Proper methods should be adopted for management of solid waste

disposal. Industrial wastes can be treated physically, chemically and biologically until they are

less hazardous. Acidic and alkaline wastes should be first neutralized; the insoluble material if

biodegradable should be allowed to degrade under controlled conditions before being disposed. As a last resort, new areas for storage of hazardous waste should be

investigated such as deep well injection and more secure landfills. Burying the waste in locations

situated away from residential areas is the simplest and most widely used technique of solid waste

management. Environmental and aesthetic considerations must be taken into consideration before

selecting the dumping sites. Incineration of other wastes is expensive and leaves a huge residue

and adds to air pollution. Pyrolysis is a process of combustion in absence of oxygen or the

material burnt under controlled

atmosphere of oxygen. It is an alternative to incineration. The gas and liquid thus obtained can be used

as fuels. Pyrolysis of carbonaceous wastes like firewood, coconut, palm waste, corn combs, cashew

shell, rice husk paddy straw and saw dust, yields charcoal along with products like tar, methyl alcohol,

acetic acid, acetone and a fuel gas. Anaerobic/aerobic decomposition of biodegradable municipal

and domestic waste is also being done and gives organic manure. Cow dung which releases methane

into the atmosphere, should be processed further in 'gobar gas plants' to produce 'gobar gas'

and good manure.

Natural land pollution: Land pollution occurs massively during earth quakes, land slides,

hurricanes and floods. All cause hard to clean mess, which is expensive to clean , and may sometimes take

years to restore the affected area. These kinds of natural disasters are not only a problem in that they

cause pollution but also because they leave many victims homeless.

Thermal pollutionFrom Wikipedia, the free encyclopediaJump to: navigation, search

Potrero Generating Station discharged heated water into San Francisco Bay.[1] The plant was closed in 2011.[2]

Thermal pollution is the degradation of water quality by any process that changes ambient water temperature.

A common cause of thermal pollution is the use of water as a coolant, stormwater by power plants and industrial manufacturers. When water used as a coolant is returned to the natural environment at a higher temperature, the change in temperature decreases oxygen supply, and affects ecosystem composition. Urban runoff–stormwater discharged to surface waters from roads and parking lots–can also be a source of elevated water temperatures.

When a power plant first opens or shuts down for repair or other causes, fish and other organisms adapted to particular temperature range can be killed by the abrupt change in water temperature known as "thermal shock."

Contents

1 Ecological effects o 1.1 Warm water o 1.2 Cold water

2 Control of thermal pollution o 2.1 Industrial wastewater o 2.2 Urban runoff

3 See also 4 References

Ecological effects

Warm water

This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (March 2011)

Elevated temperature typically decreases the level of dissolved oxygen in water. This can harm aquatic animals such as fish, amphibians and other aquatic organisms. Thermal pollution may also increase the metabolic rate of aquatic animals, as enzyme activity, resulting in these organisms consuming more food in a shorter time than if their environment were not changed.[3]:179 An increased metabolic rate may result in fewer resources; the more adapted organisms moving in may have an advantage over organisms that are not used to the warmer temperature. As a result, food chains of the old and new environments may be compromised. Some fish species will avoid stream segments or coastal areas adjacent to a thermal discharge. Biodiversity can be decreased as a result.[4]:415-17 [5]:340

High temperature limits oxygen dispersion into deeper waters, contributing to anaerobic conditions. This can lead to increased bacteria levels when there is ample food supply. Many aquatic species will fail to reproduce at elevated temperatures.[3]:179-80

Primary producers are affected by warm water because higher water temperature increases plant growth rates, resulting in a shorter lifespan and species overpopulation. This can cause an algae bloom which reduces oxygen levels.

Temperature changes of even one to two degrees Celsius can cause significant changes in organism metabolism and other adverse cellular biology effects. Principal adverse changes can include rendering cell walls less permeable to necessary osmosis, coagulation of cell proteins, and alteration of enzyme metabolism. These cellular level effects can adversely affect mortality and reproduction.

A large increase in temperature can lead to the denaturing of life-supporting enzymes by breaking down hydrogen- and disulphide bonds within the quaternary structure of the enzymes. Decreased enzyme activity in aquatic organisms can cause problems such as the inability to break down lipids, which leads to malnutrition.

In limited cases, warm water has little deleterious effect and may even lead to improved function of the receiving aquatic ecosystem. This phenomenon is seen especially in seasonal waters and is known as thermal enrichment. An extreme case is derived from the aggregational habits of the manatee, which often uses power plant discharge sites during winter. Projections suggest that manatee populations would decline upon the removal of these discharges.

Cold water

Releases of unnaturally cold water from reservoirs can dramatically change the fish and macroinvertebrate fauna of rivers, and reduce river productivity. In Australia, where many rivers have warmer temperature regimes, native fish species have been eliminated, and macroinvertebrate fauna have been drastically altered. Due to the sudden fall of water temperature the contraction on dam and bridge pylon may take place.

Control of thermal pollution

Cooling tower at Gustav Knepper Power Station, Dortmund, Germany

Industrial wastewater

In the United States, about 75 to 82 percent of thermal pollution is generated by power plants.[5]:335 The remainder is from industrial sources such as petroleum refineries, pulp and paper mills, chemical plants, steel mills and smelters.[6][7] Heated water from these sources may be controlled with:

cooling ponds , man-made bodies of water designed for cooling by evaporation, convection, and radiation

cooling towers , which transfer waste heat to the atmosphere through evaporation and/or heat transfer

cogeneration , a process where waste heat is recycled for domestic and/or industrial heating purposes.[8]

Some facilities use once-through cooling (OTC) systems which do not reduce temperature as effectively as the above systems. For example, the Potrero Generating Station in San Francisco, which uses OTC, discharges water to San Francisco Bay approximately 10°C (20°F) above the ambient bay temperature.[9]

Urban runoff

During warm weather, urban runoff can have significant thermal impacts on small streams, as stormwater passes over hot parking lots, roads and sidewalks. Stormwater management facilities that absorb runoff or direct it into groundwater, such as bioretention systems and infiltration basins, can reduce these thermal effects. Retention basins tend to be less effective at reducing temperature, as the water may be heated by the sun before being discharged to a receiving stream.[10]

See also

Book: Pollution

Water cooling Water pollution Water quality

References

1. ̂ Selna, Robert (2009). "Power plant has no plans to stop killing fish." San Francisco Chronicle, January 2, 2009.

2. ̂ Pacific Gas & Electric Co. "Potrero Power Plant: Site Overview." Accessed 2012-07-17.

3. ^ a b Goel, P.K. (2006). Water Pollution - Causes, Effects and Control. New Delhi: New Age International. ISBN 978-81-224-1839-2.

4. ̂ Kennish, Michael J. (1992). Ecology of Estuaries: Anthropogenic Effects. Marine Science Series. Boca Raton, FL: CRC Press. ISBN 978-0-8493-8041-9.

5. ^ a b Laws, Edward A. (2000). Aquatic Pollution: An Introductory Text. New York: John Wiley and Sons. ISBN 978-0-471-34875-7.

6. ̂ U.S. Environmental Protection Agency (EPA). Washington, D.C. "Cooling Water Intake Structures - Basic Information." June 2, 2008.

7. ̂ EPA. "Technical Development Document for the Final Section 316(b) Phase III Rule." June 2006. Chapter 2.

8. ̂ EPA (1997). Profile of the Fossil Fuel Electric Power Generation Industry (Report). Document No. EPA/310-R-97-007. p. 24.

9. ̂ California Environmental Protection Agency. San Francisco Bay Regional Water Quality Control Board. "Waste Discharge Requirements for Mirant Potrero, LLC, Potrero Power Plant." Order No. R2-2006-0032; NPDES Permit No. CA0005657. May 10, 2006.

10. ̂ EPA. "Preliminary Data Summary of Urban Storm Water Best Management Practices." August 1999. Document No. EPA-821-R-99-012. p. 5-58.

Michael Hogan, Leda C. Patmore and Harry Seidman (1973). Statistical Prediction of Dynamic Thermal Equilibrium Temperatures using Standard Meteorological Data Bases. EPA Office of Research and Development, document no EPA-660/2-73-003. August 1973.

E.L. Thackston and F.L. Parker (1971). Effect of Geographical Location on Cooling Pond Requirements. Vanderbilt University, for Water Quality Office, EPA, Project no. 16130 FDQ, March 1971.

Edinger, J.E.; Geyer, J.C (1965). Heat Exchange in the Environment. New York: Edison Electric Institute.

[show]

v t e

Pollution

[hide]  Aquatic ecosystems – general and freshwater components

General Aquatic ecosystems Acoustic ecology Agent-based models Algal bloom Anoxic waters Aquatic adaptation

Aquatic animals Aquatic biodiversity research Aquatic biomonitoring Aquatic insects Aquatic layers Aquatic mammals Aquatic plants Aquatic predation Aquatic respiration Aquatic science Aquatic toxicology Benthos Bioluminescence Biomass Cascade effect Colored dissolved organic matter Dead zone Ecohydrology Eutrophication Fisheries science Food chain Food web GIS and aquatic science Hydrobiology Hypoxia Isotope analysis Microbial ecology Microbial food web Microbial loop Nekton Neuston Particle Photic zone Phytoplankton Plankton Productivity Ramsar Convention Schooling Sediment trap Siltation Spawning Substrate Thermal pollution Trophic level Underwater camouflage and mimicry Water column

Zooplankton More...

Freshwater

Freshwater ecosystems Brackish marsh Freshwater biology Freshwater biomes Freshwater fish Freshwater marsh Freshwater swamp forest Hyporheic zone Lake ecosystems Landscape limnology Limnology Lake stratification Macrophyte Pond Fish pond Rheotaxis River ecosystems Stream bed Stream pool Trophic state index Upland and lowland Water garden Wetland Environmental quality More...

Ecoregions

Freshwater ecoregions List of freshwater ecoregions Marine ecoregions List of marine ecoregions Ecology of the Everglades Ecology of the San Francisco Estuary Ecosystem of the North Pacific Subtropical Gyre Freshwater ecology of Maharashtra

[show]  Aquatic ecosystems – marine components

View page ratingsRate this pageWhat's this?

TrustworthyObjectiveCompleteWell-written

I am highly knowledgeable about this topic (optional) Categories:

Aquatic ecology Water pollution Pollution Environmental issues with energy

Navigation menu

Create account Log in

Article Talk

Read Edit View history

Main page Contents Featured content Current events Random article Donate to Wikipedia

Interaction

Help About Wikipedia Community portal Recent changes Contact Wikipedia

Toolbox

Print/export

Languages

العربية Español Français हि�न्दी� עברית ಕನ್ನ�ಡ മലയാ�ളം� Polski Português सं�स्कृ� तम्� Suomi தமி�ழ் 中文

This page was last modified on 22 January 2013 at 21:48. Text is available under the Creative Commons Attribution-ShareAlike License;

additional terms may apply. See Terms of Use for details.Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization.

Contact us

Privacy policy About Wikipedia Disclaimers Mobile view