
Water pollution (or aquatic pollution) is the contamination of
water bodies
( Lysefjord) in Norway
Norway ( nb, ; nn, ; se, Norga; smj, Vuodna; sma, Nöörje), officially the Kingdom of Norway, is a Nordic countries, Nordic country in Northern Europe whose mainland territory comprises the western and nort ...

, usually as a result of human activities, in such a manner that negatively affects its legitimate uses.
Water pollution reduces the ability of the body of water to provide the
ecosystem services
Ecosystem services are the many and varied benefits to humans provided by the natural environment and from healthy . Such ecosystems include, for example, s, s, s and s. These ecosystems, functioning in healthy relationship, offer such things ...
that it would otherwise provide. Water bodies include for example
lake
A lake is an area filled with water, localized in a Depression (geology), basin, surrounded by land, and set apart from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the World Ocean, oc ...

s,
river
A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of wate ...

s,
ocean
The ocean (also the or the world ocean) is the body of that covers approximately 70.8% of the surface of and contains 97% of . Another definition is "any of the large bodies of water into which the great ocean is divided". s,
aquifer
An aquifer is an underground layer of -bearing , rock fractures or unconsolidated materials (, , or ). can be extracted using a water . The study of water flow in aquifers and the characterization of aquifers is called . Related terms include a ...

s,
reservoir
A reservoir (; from French
French (french: français(e), link=no) may refer to:
* Something of, from, or related to France
France (), officially the French Republic (french: link=no, République française), is a country primarily loca ...

s and
groundwater
Groundwater is the water
Water (chemical formula H2O) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living ...

. Water pollution results when
contaminant
Contamination is the presence of a constituent, impurity, or some other undesirable element that spoils, corrupts, infects, makes unfit, or makes inferior a material, physical body, natural environment, workplace, etc.
Nuances of contamination ...
s are introduced into these water bodies. In addition to damage to many
species
In biology, a species is the basic unit of biological classification, classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individu ...

, water pollution can also lead to
water-borne diseases
Waterborne diseases are conditions caused by pathogenic microorganism, micro-organisms that are transmitted in water. These Disease, diseases can be spread while bathing, washing, drinking water, or by eating food exposed to contaminated water. Wh ...
for people. Water pollution traditionally is attributed to four sources, which provide the organization of this article:
*sewage
*industry
*agriculture
*urban runoff including stormwater.
Water pollution can also be classified as
surface water
An example of surface water is Lake Kinney.
Surface water is water
Water is an Inorganic compound, inorganic, Transparency and translucency, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which ...
pollution (for example lakes, streams, estuaries, and parts of the ocean in
marine pollution
Marine pollution occurs when substances used or spread by humans, such as industrial waste, industrial, agricultural pollution, agricultural and municipal solid waste, residential waste, particle (ecology), particles, noise, excess carbon dioxi ...
) or
groundwater
Groundwater is the water
Water (chemical formula H2O) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living ...

pollution. Sources of water pollution are either
point source
A point source is a single identifiable ''localised'' source of something. A point source has negligible extent, distinguishing it from other source geometries. Sources are called point sources because in mathematical modeling, these sources can us ...
s or
non-point source
Nonpoint source (NPS) pollution is pollution resulting from many diffuse sources, in direct contrast to point source pollution which results from a single source. Nonpoint source pollution generally results from Surface runoff, land runoff, precipit ...
s. Point sources have one identifiable cause, such as a
storm drain
A storm drain, storm sewer (United Kingdom
The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain,Usage is mixed. The Guardian' and Telegraph' use Britain as a synonym for the Unite ...

or a
wastewater treatment plant
Wastewater treatment is a process used to remove contaminants
Contamination is the presence of a constituent, impurity, or some other undesirable element that spoils, corrupts, infects, makes unfit, or makes inferior a material, physical body ...
. Non-point sources are more diffuse, such as
agricultural runoff
Agriculture is the science, art and practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated
Domestication is a sustained multi-generat ...
.
Pollution is the result of the cumulative effect over time. Supplying clean
drinking water
Drinking water, also known as potable water, is that is safe to or use for . The amount of drinking water required to maintain good health varies, and depends on physical activity level, age, health-related issues, and environmental conditions ...

is an important ecosystem service provided by some freshwater systems, but approximately 785 million people in the world do not have access to clean drinking water because of pollution.
Definition
A practical definition of water pollution is: "Water pollution is the addition of substances or energy forms that directly or indirectly alter the nature of the water body in such a manner that negatively affects its legitimate uses".
Therefore, pollution is associated with concepts attributed to humans, namely the negative alterations and the uses of the water body. Water is typically referred to as polluted when it is impaired by
anthropogenic
Anthropogenic ("human" + "generating") is an adjective that may refer to:
* Anthropogeny, the study of the origins of humanity
Counterintuitively, anthropogenic may also refer to things that have been generated by humans, as follows:
* Human imp ...
contaminants. Due to these contaminants it either does not support a human use, such as
drinking water
Drinking water, also known as potable water, is that is safe to or use for . The amount of drinking water required to maintain good health varies, and depends on physical activity level, age, health-related issues, and environmental conditions ...

, or undergoes a marked shift in its ability to support its biotic communities, such as fish.
Agriculture

Agriculture is a major contributor to water pollution. The use of fertilizers leads to
Nutrient pollution
Nutrient pollution, a form of water pollution
Water pollution (or aquatic pollution) is the contamination of water bodies
( Lysefjord) in Norway
Norway ( nb, ; nn, ; se, Norga; smj, Vuodna; sma, Nöörje), officially the King ...
, in which excess nutrients, usually caused by
nitrogen
Nitrogen is the chemical element
upright=1.0, 500px, The chemical elements ordered by link=Periodic table
In chemistry
Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science ...

- or
phosphorus
Phosphorus is a chemical element with the Symbol (chemistry), symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly Reactivity (chemistry), reactive, phosphor ...

-containing compounds that are the main components. Sources of nutrient pollution include
surface runoff
Surface runoff (also known as overland flow) is the flow of water
Water (chemical formula H2O) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydros ...
from farm fields and pastures, discharges from
septic tank
A septic tank is an underground chamber made of concrete, fiberglass, or plastic through which domestic wastewater (sewage) flows for Sewage treatment, basic treatment. Settling and Anaerobic digestion, anaerobic processes reduce solids and orga ...

s and
feedlot
A feedlot or feed yard is a type of animal feeding operation (AFO) which is used in intensive animal farming, notably beef
Beef is the culinary name for meat
Meat is animal flesh that is eaten as food. Humans have hunted and killed an ...

s (
sewage
Sewage (or domestic sewage, domestic wastewater, municipal wastewater) is a type of wastewater
Wastewater is generated after the use of fresh water
Water (chemical formula H2O) is an inorganic, transparent, tasteless, odorless, and n ...
- see below - is also high in nutrients). In addition to plant-focused agriculture, fish-farming is also a source of pollution.
Additionally, ag runoff often contains high levels of pesticides.
[
]
Industrial wastewater
Using the US as an example, the main industrial consumers of water (using over 60% of the total consumption) are power plants, petroleum refineries, iron and steel mills, pulp and paper mills, and food processing industries.[
Some industries discharge chemical wastes, including solvents and heavy metals (which are toxic) and other harmful pollutants such as nutrients. Certain industries (e.g. food processing) discharge high concentrations of ]biochemical oxygen demand
Biochemical oxygen demand (BOD) is the amount of dissolved oxygen
Oxygen saturation (symbol SO2) is a relative measure of the concentration of oxygen
Oxygen is the chemical element with the chemical symbol, symbol O and atomic nu ...
(BOD) and oil and grease. Some industrial discharges include persistent organic pollutant
Persistent organic pollutants (POPs), sometimes known as "forever chemicals", are organic compounds
, CH4; is among the simplest organic compounds.
In chemistry
Chemistry is the science, scientific study of the properties and behavior of ...
s such as per- and polyfluoroalkyl substances
Per- and polyfluoroalkyl substances (PFASs, also perfluorinated alkylated substances) are synthetic organofluorine chemical compounds that have multiple fluorine atoms attached to an alkyl chain. As such, they contain at least one perfluoroalkyl ...
(PFAS).
Sewage
Sewage typically consists of 99.9% water and 0.1% solids.
Globally, about 4.5 billion people do not have safely managed sanitation
Sanitation refers to public health conditions related to clean drinking water and adequate treatment and disposal of Human waste, human excreta and sewage. Risk management, Preventing human contact with feces is part of sanitation, as is hand was ...
as of 2017, according to an estimate by the Joint Monitoring Programme for Water Supply and Sanitation
The Joint Monitoring Programme (JMP) for Water Supply and Sanitation by WHO and UNICEF is the official United Nations mechanism tasked with monitoring progress towards the Sustainable Development Goal Number 6 (SDG 6) since 2016.
Previously, unti ...
.[WHO and UNICEF (2017]
Progress on Drinking Water, Sanitation and Hygiene: 2017 Update and SDG Baselines
Geneva: World Health Organization (WHO) and the United Nations Children's Fund (UNICEF), 2017 Lack of access to sanitation often leads to water pollution, e.g. via the practice of open defecation
Open defecation is the human practice of defecating
frame, Anatomy of the anus and rectum
Defecation is the final act of digestion
Digestion is the breakdown of large insoluble food
Food is any substance consumed to provide nutri ...
. Simple pit latrines
A pit latrine, also known as pit toilet, is a type of toilet
A toilet is a piece of sanitary hardware used for the collection or disposal of human urine and Human feces, feces. Toilets can be with or without flushing water (flush toilet o ...
may also get flooded during rain events. When sewers overflow during storm events this can lead to water pollution from untreated sewage. Such events are called sanitary sewer overflow
Sanitary sewer overflow (SSO) is a condition in which untreated sewage
Sewage, or domestic/municipal wastewater, is a type of wastewater that is produced by a community of people. It is characterized by volume
Volume is the quantity of t ...
s or combined sewer overflows.
Sewage contributes many classes of nutrients that lead to eutrophication. It is a major source of phosphate for example.
Sewage is often contaminated with diverse compounds found in personal hygiene
Hygiene is a series of practices performed to preserve health
Health, according to the World Health Organization
The World Health Organization (WHO) is a specialized agency of the United Nations
United Nations Specialized Agencies a ...

, cosmetic
Cosmetic may refer to:
*Cosmetics, or make-up, substances to enhance the beauty of the human body, apart from simple cleaning
*Cosmetic, an adjective describing beauty, aesthetics, or appearance, especially concerning the human body
*Cosmetic, a top ...
s, pharmaceutical drugs
A medication (also referred to as medicine, pharmaceutical drug, medicinal drug or simply drug) is a drug
File:Aspirine macro shot.jpg, Uncoated aspirin Tablet (pharmacy), tablets, consisting of about 90% acetylsalicylic acid, along with a ...
] (see also drug pollution), and their metabolites Even at very low concentrations, hormones
A hormone (from the Greek
Greek may refer to:
Greece
Anything of, from, or related to Greece
Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country located in Southeast Europe. Its population is approximately 10.7 m ...

(from animal husbandry
Animal husbandry is the branch of agriculture
Agriculture is the science, art and practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary
Image:Family watching television 1958.jpg, Ex ...
and residue from human hormonal contraception
Hormonal contraception refers to birth control methods that act on the endocrine system. Almost all methods are composed of steroid hormones, although in India one selective estrogen receptor modulator is marketed as a contraceptive. The original h ...
methods) and synthetic materials such as phthalates
Phthalates (, ), or phthalate esters, are esters of phthalic acid. They are mainly used as plasticizers, i.e., substances added to plastics to increase their flexibility, transparency, durability, and longevity. They are used primarily to soften ...

that mimic hormones in their action, can have an adverse impacts. Water pollution due to environmental persistent pharmaceutical pollutants can have wide-ranging consequences:
Pathogens from sewage
The source of high levels of pathogens in water bodies can be from human feces
Human feces (or faeces in British English
British English (BrE) is the standard dialect
A standard language (also standard variety, standard dialect, and standard) is a language variety that has undergone substantial codification of gra ...

(due to open defecation
Open defecation is the human practice of defecating
frame, Anatomy of the anus and rectum
Defecation is the final act of digestion
Digestion is the breakdown of large insoluble food
Food is any substance consumed to provide nutri ...
), sewage
Sewage (or domestic sewage, domestic wastewater, municipal wastewater) is a type of wastewater
Wastewater is generated after the use of fresh water
Water (chemical formula H2O) is an inorganic, transparent, tasteless, odorless, and n ...
, blackwaterBlackwater or Black Water may refer to:
Health and ecology
* Blackwater (coal), liquid waste from coal preparation
* Blackwater (waste), wastewater containing feces, urine, and flushwater from flush toilets
* Blackwater fever, an acute kidney diseas ...
, manure
Manure is organic matter
Organic matter, organic material, or natural organic matter refers to the large source of Carbon compounds, carbon-based compounds found within natural and engineered, terrestrial, and aquatic environments. It is m ...

that has found its way into the water body. The cause for this can be lack of sanitation or poorly functioning on-site sanitation
Sanitation refers to public health
Public health has been defined as "the science and art of Preventive healthcare, preventing disease", prolonging life and improving quality of life through organized efforts and informed choices of society ...

systems (septic tank
A septic tank is an underground chamber made of concrete, fiberglass, or plastic through which domestic wastewater (sewage) flows for Sewage treatment, basic treatment. Settling and Anaerobic digestion, anaerobic processes reduce solids and orga ...

s, pit latrine
A pit latrine, also known as pit toilet, is a type of toilet
A toilet is a piece of sanitary hardware that collects human urine and Human feces, feces, and sometimes toilet paper, usually for disposal. Flush toilets use water, while dry ...
s), sewage treatment plants without disinfection steps, sanitary sewer overflow
Sanitary sewer overflow (SSO) is a condition in which untreated sewage
Sewage, or domestic/municipal wastewater, is a type of wastewater that is produced by a community of people. It is characterized by volume
Volume is the quantity of t ...
s and combined sewer overflows (CSOs) during storm events and intensive agriculture
Intensive agriculture, also known as intensive farming (as opposed to extensive farming
Extensive farming or extensive agriculture (as opposed to intensive farming) is an agricultural
Agriculture is the science, art and practice of cultiv ...
(poorly managed livestock operations). Pathogens can produce waterborne diseases
Waterborne diseases are conditions (meaning adverse effects on human health, such as death, disability, illness or disorders) caused by pathogenic microorganism, micro-organisms that are transmitted in water. The study of pathogenic microbes is a ...
in either human or animal hosts. Some microorganisms sometimes found in contaminated surface waters that have caused human health problems include: ''Burkholderia pseudomallei
''Burkholderia pseudomallei'' (also known as ''Pseudomonas pseudomallei'') is a Gram-negative, bipolar, Aerobic organism, aerobic, motile rod-shaped bacterium. It is a soil-dwelling bacterium endemic in Tropics, tropical and Subtropics, subtropica ...
,'' ''Cryptosporidium parvum
''Cryptosporidium parvum'' is one of several species that cause cryptosporidiosis, a parasitic disease
A parasitic disease, also known as parasitosis, is an infectious disease
An infection is the invasion of an organism's body Tissue (biology ...

,'' ''Giardia lamblia
''Giardia duodenalis'', also known as ''Giardia intestinalis'' and ''Giardia lamblia'', is a flagellate
's '' Artforms of Nature'', 1904
(''Giardia lamblia'')
('' Chlamydomonas'')
A flagellate is a cell or organism with one or more whip-like ...

,'' ''Salmonella
''Salmonella'' is a genus
Genus /ˈdʒiː.nəs/ (plural genera /ˈdʒen.ər.ə/) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruse ...
,'' norovirus
Norovirus, sometimes referred to as the winter vomiting bug, is the most common cause of gastroenteritis. Infection is characterized by non-bloody diarrhea, vomiting, and stomach pain. Fever or headaches may also occur. Symptoms usually develop ...
and other viruses, parasitic worms
Parasitic worms, also known as helminths, are large macroparasites; adults can generally be seen with the naked eye. Many are intestinal worms that are soil-transmitted helminth, soil-transmitted and intestinal parasite infection, infect the gas ...
including the ''Schistosoma
''Schistosoma'' is a genus
Genus /ˈdʒiː.nəs/ (plural genera /ˈdʒen.ər.ə/) is a taxonomic rank
In biological classification
In biology, taxonomy () is the scientific study of naming, defining (Circumscription (taxonomy), ci ...

'' type.'
A study published in 2017 stated that "polluted water spread gastrointestinal disease
Gastrointestinal diseases (abbrev. GI diseases or GI illnesses) refer to diseases involving the gastrointestinal tract
The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system
...
s and parasitic infections
Parasitism is a symbiotic
Symbiosis (from Ancient Greek, Greek , , "living together", from , , "together", and , bíōsis, "living") is any type of a close and long-term biological interaction between two different Organism, biological or ...
and killed 1.8 million people" (these are also referred to as waterborne diseases
Waterborne diseases are conditions (meaning adverse effects on human health, such as death, disability, illness or disorders) caused by pathogenic microorganism, micro-organisms that are transmitted in water. The study of pathogenic microbes is a ...
).
Urban runoff
Urban runoff is stormwater discharged to surface waters from rooftops, roads and parking lots, and reservoirs. Often it is captured in large retaining ponds. It is subject to high suspended solids as well and elevated nitrogen and phosphorus concentrations.[
]
Other forms of water pollution
Thermal pollution
Thermal pollution
Thermal pollution, sometimes called "thermal enrichment," is the degradation of water quality by any process that changes ambient water temperature
Temperature is a physical quantity that expresses hot and cold. It is the manifestation of ...
, sometimes called "thermal enrichment," is the degradation of water quality by any process that changes ambient water temperature. 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.
Biological pollution
The introduction of aquatic invasive organisms is a form of water pollution as well. It causes biological pollution.
By type of source
Sources of surface water pollution can be grouped into two categories based on their origin: point sources and nonpoint sources.
Point sources
Point source water pollution refers to contaminants that enter a waterway from a single, identifiable source, such as a pipe
Pipe(s) or PIPE(S) may refer to:
Common uses
* Pipe (fluid conveyance)
Carbon Steel Pipe in a storage yard
Plastic (PVC) pipes
A pipe is a tubular section or hollow cylinder
A cylinder (from ) has traditionally been a Solid geometry ...

or ditch
150px, Waterplants growing in a ditch in the Netherlands, showing ''Sagittaria sagittifolia'' to the right.
A ditch is a small to moderate divot created to channel water. A ditch can be used for drainage, to drain water from low-lying areas, alo ...

. Examples of sources in this category include discharges from a sewage treatment plant, a factory, or a city storm drain
A storm drain, storm sewer (United Kingdom
The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain,Usage is mixed. The Guardian' and Telegraph' use Britain as a synonym for the Unite ...

.
The U.S. Clean Water Act
The Clean Water Act (CWA) is the primary federal law
Federal law is the body of law created by the federal government of a country. A federal government is formed when a group of political units, such as state (subnational), states or province ...
(CWA) defines point source for regulatory
Regulation is the management of complex systems according to a set of rules and trends. In systems theory, these types of rules exist in various fields of biology and society, but the term has slightly different meanings according to context. For ...

enforcement purposes (see United States regulation of point source water pollution
Point source
A point source is a single identifiable ''localised'' source of something. A point source has negligible extent, distinguishing it from other source geometries. Sources are called point sources because in mathematical modeling, thes ...
). The CWA definition of point source was amended in 1987 to include municipal storm sewer systems, as well as industrial storm water, such as from construction sites.
Nonpoint sources
Measurement
Water pollution may be analyzed through several broad categories of methods: physical, chemical and biological. Some methods may be conducted ''in situ
''In situ'' (; often not italicized in English) is a Latin
Latin (, or , ) is a classical language
A classical language is a language
A language is a structured system of communication
Communication (from Latin ''communicar ...

'', without sampling, such as temperature. Others involve collection of samples, followed by specialized analytical tests in the laboratory. Standardized, validated analytical test methods, for water and wastewater samples have been published.
Common physical tests of water include temperature, Specific conductance or electrical conductance
The electrical resistance of an object is a measure of its opposition to the flow of electric current. Its Multiplicative inverse, reciprocal quantity is , measuring the ease with which an electric current passes. Electrical resistance shares so ...
(EC) or conductivity, solids concentrations (e.g., total suspended solids
Total suspended solids (TSS) is the dry-weight of suspended particles, that are not dissolved, in a sample of water that can be trapped by a filter
Filter, filtering or filters may refer to:
Science and technology Device
* Filter (chemistry), a ...
(TSS)) and turbidity
Turbidity is the cloudiness or haziness of a fluid
In physics, a fluid is a substance that continually Deformation (mechanics), deforms (flows) under an applied shear stress, or external force. Fluids are a Phase (matter), phase of matter ...

. Water samples may be examined using analytical chemistry
Analytical chemistry studies and uses instruments and methods used to separate, identify, and quantify matter. In practice, separation, identification or quantification may constitute the entire analysis or be combined with another method. Sepa ...
methods. Many published test methods are available for both organic and inorganic compounds. Frequently used parameters that are quantified are , biochemical oxygen demand
Biochemical oxygen demand (BOD) is the amount of dissolved oxygen
Oxygen saturation (symbol SO2) is a relative measure of the concentration of oxygen
Oxygen is the chemical element with the chemical symbol, symbol O and atomic nu ...
(BOD), chemical oxygen demand
In environmental chemistry
Environmental chemistry is the scientific study of the chemical and biochemical phenomena that occur in natural places. It should not be confused with green chemistry, which seeks to reduce potential pollution at its so ...
(COD), dissolved oxygen
Oxygen saturation (symbol SO2) is a relative measure of the concentration of oxygen
Oxygen is the chemical element
Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements
In c ...
(DO), total hardness, nutrients (nitrogen
Nitrogen is the chemical element
upright=1.0, 500px, The chemical elements ordered by link=Periodic table
In chemistry
Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science ...

and phosphorus
Phosphorus is a chemical element with the Symbol (chemistry), symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly Reactivity (chemistry), reactive, phosphor ...

compounds, e.g. nitrate
Nitrate is a polyatomic ion
A polyatomic ion, also known as a molecular ion, is a covalently bonded
A covalent bond is a chemical bond
A chemical bond is a lasting attraction between atoms, ions or molecules that enables the format ...

and orthophosphate
A phosphoric acid, in the general sense, is a phosphorus oxoacid in which each phosphorus
Phosphorus is a chemical element with the Symbol (chemistry), symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosph ...
s), metals (including copper, zinc
Zinc is a chemical element
In chemistry, an element is a pure Chemical substance, substance consisting only of atoms that all have the same numbers of protons in their atomic nucleus, nuclei. Unlike chemical compounds, chemical element ...

, cadmium
Cadmium is a chemical element
In chemistry, an element is a pure Chemical substance, substance consisting only of atoms that all have the same numbers of protons in their atomic nucleus, nuclei. Unlike chemical compounds, chemical eleme ...

, lead and mercury
Mercury usually refers to:
* Mercury (planet)
Mercury is the smallest planet in the Solar System and the closest to the Sun. Its orbit around the Sun takes 87.97 Earth days, the shortest of all the Sun's planets. It is named after the Roman g ...

), oil and grease, total petroleum
Petroleum, also known as crude oil and oil, is a naturally occurring, yellowish-black liquid
A liquid is a nearly incompressible
In fluid mechanics or more generally continuum mechanics, incompressible flow (isochoric process, isoc ...

hydrocarbons (TPH), surfactant
Surfactants are compounds that lower the surface tension
Surface tension is the tendency of liquid surfaces at rest to shrink into the minimum surface area possible. Surface tension is what allows objects with a higher density than wate ...

s and pesticide
Pesticides are substances that are meant to control pests
Pest or The Pest may refer to:
Science and medicine
* Pest (organism), an animal or plant detrimental to humans or human concerns
** Weed, a plant considered undesirable
* Infectious d ...
s.
Sampling
Biological testing
The use of a biomonitor is described as biological monitoring. This refers to the measurement of specific properties of an organism to obtain information on the surrounding physical and chemical environment. Biological testing involves the use of plant, animal or microbial indicators to monitor the health of an aquatic ecosystem
An aquatic ecosystem is an ecosystem in a body of water. Biocoenosis, Communities of biota (ecology), organisms that are dependent on each other and on their environment live in aquatic ecosystems. The two main types of aquatic ecosystems are ma ...

. They are any biological species
In biology, a species is the basic unit of biological classification, classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individu ...
or group of species whose function, population, or status can reveal what degree of ecosystem or environmental integrity is present. One example of a group of bio-indicators are the copepod
Copepods (; meaning "oar-feet") are a group of small crustaceans found in nearly every freshwater and saltwater habitat (ecology), habitat. Some species are planktonic (inhabiting sea waters), some are benthos, benthic (living on the ocean floor), ...

s and other small water crustacean
Crustaceans (Crustacea ) form a large, diverse arthropod taxon which includes such animals as crabs, lobsters, crayfish, Caridea, shrimp, krill, Dendrobranchiata, prawns, woodlice, barnacles, copepods, amphipoda, amphipods and mantis shrimp. The ...
s that are present in many water bodies. Such organisms can be monitored for changes (biochemical, physiological, or behavioral) that may indicate a problem within their ecosystem.
Prevalence
Water pollution is a problem in developing countries
A developing country is a sovereign state with a less developed Industrial sector, industrial base and a low Human Development Index (HDI) relative to other countries. However, this definition is not universally agreed upon. There is also no ...
as well as in developed countries
A developed country (or industrialized country, high-income country, more economically developed country (MEDC), advanced country) is a sovereign state
A sovereign state is a political entity that is represented by one centralized governmen ...
.
By country
For example, water pollution in India and China
China (), officially the People's Republic of China (PRC; ), is a country in East Asia
East Asia is the eastern region of Asia
Asia () is Earth's largest and most populous continent, located primarily in the Eastern Hemisphere ...
is wide spread. About 90 percent of the water in the cities of China is polluted.
Control and reduction
Pollution control philosophy
One aspect of environmental protection are mandatory regulations but they are only part of the solution. Other important tools in pollution control include environmental education, economic instruments, market forces and stricter enforcements. Standards can be "precise" (for a defined quantifiable minimum or maximum value for a pollutant), or "imprecise" which would require the use of Best Available Technology
The best available technology or best available techniques (BAT) is the technology approved by legislators or regulators for meeting output standards for a particular process, such as pollution abatement or pasteurization. Similar terms are ''best ...
(BAT) or Best Practicable Environmental Option (BPEO). Market-based economic instruments for pollution control can include: charges, subsidies, deposit or refund schemes, the creation of a market in pollution credits, and enforcement incentives.
Moving towards a holistic approach in chemical pollution control combines the following approaches: Integrated control measures, trans-boundary considerations, complementary and supplementary control measures, life-cycle considerations, the impacts of chemical mixtures.
Control of water pollution requires appropriate infrastructure
Infrastructure is the set of fundamental facilities and systems that support the sustainable functionality of households and firms. Serving a country, city, or other area, including the services and facilities necessary for its economy
An eco ...

and management plans. The infrastructure may include wastewater treatment plants
Wastewater is any water
Water is an Inorganic compound, inorganic, Transparency and translucency, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the main constituent of Earth's hydrosph ...
, for example sewage treatment plants and industrial wastewater
Industrial wastewater treatment describes the processes used for treating wastewater that is produced by industries as an undesirable by-product. After treatment, the treated industrial wastewater (or effluent) may be reused or released to a sa ...
treatment plants. Agricultural wastewater treatment
Agricultural wastewater treatment is a agenda for controlling pollution from that may be contaminated by chemicals in , , , crop residues or water.
Nonpoint source pollution
from farms is caused by from fields during rain storms. Agricultur ...
for farms, and erosion control
Erosion control is the practice of preventing or controlling wind or water erosion
In earth science, erosion is the action of surface processes (such as Surface runoff, water flow or wind) that removes soil, Rock (geology), rock, or dissolved ...
at construction sites can also help prevent water pollution. Effective control of urban runoff includes reducing speed and quantity of flow.
Water pollution requires ongoing evaluation
Evaluation is a
system
A system is a group of Interaction, interacting or interrelated elements that act according to a set of rules to form a unified whole.
A system, surrounded and influenced by its environment, is described by its bound ...

and revision of water resource policy at all levels (international down to individual aquifers and wells).
Sanitation and sewage treatment
Municipal wastewater (or sewage
Sewage (or domestic sewage, domestic wastewater, municipal wastewater) is a type of wastewater
Wastewater is generated after the use of fresh water
Water (chemical formula H2O) is an inorganic, transparent, tasteless, odorless, and n ...
) can be treated by centralized sewage treatment plants, decentralized wastewater systems, nature-based solutions
Nature-based solutions (NBS) refers to the sustainable management and use of nature for tackling socio-environmental challenges. The challenges include issues such as climate change
Climate change includes both global warming driven ...
[UN-Water (2018]
World Water Development Report 2018: Nature-based Solutions for Water
Geneva, Switzerland or in onsite sewage facilities and septic tank
A septic tank is an underground chamber made of concrete, fiberglass, or plastic through which domestic wastewater (sewage) flows for Sewage treatment, basic treatment. Settling and Anaerobic digestion, anaerobic processes reduce solids and orga ...

s. For example, waste stabilization pond
Waste stabilization ponds (WSPs or stabilization ponds or waste stabilization lagoons) are pond
A pond is an area filled with water, either natural or artificial, that is smaller than a lake
A lake is an area filled with water, localized ...
s are a low cost treatment option for sewage, particularly for regions with warm climates. UV light (sunlight) can be used to degrade some pollutants in waste stabilization ponds (sewage lagoons). The use of safely managed sanitation services would prevent water pollution caused by lack of access to sanitation.
Well-designed and operated systems (i.e., with secondary treatment stages or more advanced tertiary treatment) can remove 90 percent or more of the pollutant load in sewage. Some plants have additional systems to remove nutrient
A nutrient is a substance
Substance may refer to:
* Substance (Jainism), a term in Jain ontology to denote the base or owner of attributes
* Chemical substance, a material with a definite chemical composition
* Matter, anything that has mass and t ...
s and pathogens. While such advanced treatment techniques will undoubtedly reduce the discharges of micropollutants, they can also result in large financial costs, as well as environmentally undesirable increases in energy consumption and greenhouse gas emissions
Greenhouse gas emissions from human activities strengthen the greenhouse effect
The greenhouse effect is the process by which radiation from a planet's atmosphere warms the planet's surface to a temperature above what it would be without ...
.
Sewer overflows during storm events can be addressed by timely maintenance and upgrades of the sewerage system. In the US, cities with large combined systems have not pursued system-wide separation projects due to the high cost, but have implemented partial separation projects and green infrastructure
Green infrastructure or blue-green infrastructure refers to a network that provides the “ingredients” for solving urban and climatic challenges by building with nature.Hiltrud Pötz & Pierre Bleuze (2011). Urban green-blue grids for sustainable ...
approaches. In some cases municipalities have installed additional CSO storage facilities or expanded sewage treatment capacity.
Industrial wastewater treatment
Agricultural wastewater treatment
Management of erosion and sediment control
Sediment from construction sites can be managed by installation of erosion control
Erosion control is the practice of preventing or controlling wind or water erosion
In earth science, erosion is the action of surface processes (such as Surface runoff, water flow or wind) that removes soil, Rock (geology), rock, or dissolved ...
s, such as mulch
A mulch is a layer of material applied to the surface of soil. Reasons for applying mulch include conservation of soil moisture, improving soil fertility, fertility and health of the soil, reducing Weed control, weed growth and enhancing the vi ...

ing and hydroseeding, Kent, UK
Image:T400Hydroseeder.jpg, 300px, A commercial hydroseeder
Hydroseeding (or hydraulic mulch seeding, hydro-mulching, hydraseeding) is a planting process that uses a slurry of seed and mulch. It is often used as an erosion control techniqu ...
, and sediment control 250px, Silt Fence installed on a construction site.
A sediment control is a practice or device designed to keep eroded soil
Soil (often stylized as SOiL) is an American rock band that was formed in Chicago
(''City in a Garden''); I Will
, ...
s, such as sediment basin
A sediment basin is a temporary pond built on a construction
Construction is a general term meaning the art and science to form Physical object, objects, systems, or organizations,"Construction" def. 1.a. 1.b. and 1.c. ''Oxford English Dicti ...
s and silt fences. Discharge of toxic chemicals such as motor fuels and concrete washout can be 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.
Erosion caused by deforestation
deforestation in 1750-2004 (net loss)
showing anthropogenic modification of remaining forest.
File:MODIS (2020-08-01).jpg, 300px, Dry seasons, exacerbated by climate change, and the use of slash-and-burn methods for clearing tropical forest ...

and changes in hydrology
Hydrology (from Ancient Greek, Greek wikt:ὕδωρ, ὕδωρ, ''hýdōr'' meaning "water" and wikt:λόγος, λόγος, ''lógos'' meaning "study") is the scientific study of the movement, distribution, and management of water on Earth and ...
(soil loss due to water runoff) also results in loss of sediment and, potentially, water pollution.
Control of urban runoff (storm water)
Legislation
Some examples for legislation to control water pollution are listed below:
* In the Philippines, Republic Act 9275, otherwise known as the Philippine Clean Water Act of 2004, is the governing law on wastewater management. It states that it is the country's policy to protect, preserve and revive the quality of its fresh, brackish and marine waters, for which wastewater management plays a particular role.
* The Clean Water Act
The Clean Water Act (CWA) is the primary federal law
Federal law is the body of law created by the federal government of a country. A federal government is formed when a group of political units, such as state (subnational), states or province ...
is the primary federal law in the United States governing water pollution in surface waters. It is implemented by the U.S. Environmental Protection Agency in collaboration with states, territories, and tribes. Groundwater
Groundwater is the water
Water (chemical formula H2O) is an , transparent, tasteless, odorless, and , which is the main constituent of 's and the s of all known living organisms (in which it acts as a ). It is vital for all known form ...

protection provisions are included in the Safe Drinking Water Act
The Safe Drinking Water Act (SDWA) is the principal United States federal law, federal law in the United States intended to ensure safe drinking water for the public. Pursuant to the act, the United States Environmental Protection Agency, Environme ...
, Resource Conservation and Recovery Act
The Resource Conservation and Recovery Act (RCRA), enacted in 1976, is the principal federal law in the United States
The United States of America (USA), commonly known as the United States (U.S. or US), or America, is a country Contiguous ...
, and the Superfund
The United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, stat ...
act.
See also
* Aquatic toxicology
Aquatic toxicology is the study of the effects of manufactured chemical
A chemical substance is a form of matter having constant chemical composition and characteristic properties. Some references add that chemical substance cannot be separate ...
*
* Pollution
Pollution is the introduction of contaminant
Contamination is the presence of a constituent, impurity, or some other undesirable element that spoils, corrupts, infects, makes unfit, or makes inferior a material, physical body, natural en ...

* Trophic state index
The Trophic State Index (TSI) is a classification system designed to rate water bodies based on the amount of biological productivity they sustain. Although the term "trophic index" is commonly applied to lakes, any surface water body may be inde ...
(water quality indicator for lakes)
* Water treatment
Water treatment is any process that improves the quality
Quality may refer to:
Concepts
*Quality (business), the ''non-inferiority'' or ''superiority'' of something
*Quality (philosophy), an attribute or a property
*Quality (physics), in respo ...

*Water resources management
Water resource management is the activity of planning, developing, distributing and managing the optimum use of water resources
Water resources are natural resources of water
Water is an Inorganic compound, inorganic, Transparency an ...
References
External links
UN Environment Program page on water pollution
{{DEFAULTSORT:Water Pollution
Aquatic ecology
Aquifers
Environmental science
Environmental science
Environmental science is an interdisciplinary academic field that integrates physical, biological and information science
Information science (also known as information studies) is an academic field which is primar ...
Water and the environment
Water supply
Sanitation
Articles containing video clips