Water pollution: Difference between revisions

{{Pollution sidebar|Water|image=[[File:Nrborderborderentrythreecolorsmay05-1-.JPG|upright=1.35|frameless]]thumb|caption=[[Raw sewage]] and [[industrial waste]] in the [[New River (California)|New River]] as it passes from [[Mexicali]] (Mexico) to [[Calexico, California]]}}]]

'''Water pollution''' (or '''aquatic pollution''') is the contamination of [[Body of water|water bodies]], usuallywith as a resultnegative ofimpact human activities,on so that it negatively affects itstheir uses.<ref name="Von Sperling"/>{{rp|6}} It is usually a result of human activities. Water bodies include [[lake]]s, [[river]]s, [[ocean]]s, [[aquifer]]s, [[reservoir]]s and [[groundwater]]. Water [[pollution]] results when [[contaminant]]s mix with these water bodies. Contaminants can come from one of four main sources:. These are [[sewage]] discharges, industrial activities, agricultural activities, and urban runoff including [[stormwater]].<ref name=Eckenfelder>{{Cite book |vauthors=Eckenfelder Jr WW |url=https://onlinelibrary.wiley.com/doi/book/10.1002/0471238961 |title=Kirk‐OthmerKirk-Othmer Encyclopedia of Chemical Technology |publisher=[[John Wiley & Sons]] |year=2000 |isbn=978-0-471-48494-3 |doi=10.1002/0471238961.1615121205031105.a01}}</ref> Water pollution ismay affect either [[surface water]] pollution or [[groundwater pollution|groundwater]]. This form of pollution can lead to many problems,. suchOne asis the [[environmental degradation|degradation]] of [[aquatic ecosystems]]. orAnother is spreading [[Waterborne diseases|water-borne diseases]] when people use polluted water for drinking or [[irrigation]].<ref>{{Cite web |date=July 23, 2013 |title=Water Pollution |url=https://www.hsph.harvard.edu/ehep/82-2/ |access-date=September 18, 2021 |website=Environmental Health Education Program |publisher=[[Harvard T.H. Chan School of Public Health]] |location=Cambridge, MA |archive-date=September 18, 2021 |archive-url=https://web.archive.org/web/20210918005228/https://www.hsph.harvard.edu/ehep/82-2/ |url-status=live}}</ref> AnotherWater problempollution is that water pollutionalso reduces the [[ecosystem service]]s (such as providing [[drinking water]]) thatprovided by the [[Water resources|water resource]] would otherwise provide. The European Parliament recently approved the Drinking Water Directive (EU) 2020/2184, which contains additional restrictions on the presence of potentially dangerous compounds in water meant for human consumption ([[Per- and polyfluoroalkyl substances|polyfluoroalkyl substances]] and [[Endocrine disruptor|EDCs]]).'''<ref name=":134">{{Cite journal |last=Bank |first=European Investment |date=2023-02-27 |title=Microplastics and Micropollutants in Water: Contaminants of Emerging Concern |url=https://www.eib.org/en/publications/20230042-microplastics-and-micropollutants-in-water |language=EN}}</ref>'''

Sources of water pollution are either [[point source]]s or [[non-point source]]s.<ref>{{Cite journal |last1=Schaffner |first1=Monika |last2=Bader |first2=Hans-Peter |last3=Scheidegger |first3=Ruth |date=August 15, 2009 |title=Modeling the contribution of point sources and non-point sources to Thachin River water pollution |url=http://dx.doi.org/10.1016/j.scitotenv.2009.05.007 |journal=Science of the Total Environment |volume=407 |issue=17 |pages=4902–4915 |doi=10.1016/j.scitotenv.2009.05.007 |issn=0048-9697}}</ref> Point sources have one identifiable cause, such as a [[storm drain]], a [[wastewater treatment plant]] or an [[oil spill]]. Non-point sources are more diffuse,. suchAn example is as [[Surface runoff|agricultural runoff]].<ref name="Moss2008">{{cite journal |vauthors=Moss B |title=Water pollution by agriculture |journal=Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences |volume=363 |issue=1491 |pages=659–666 |date=February 2008 |pmid=17666391 |pmc=2610176 |doi=10.1098/rstb.2007.2176}}</ref> Pollution is the result of the cumulative effect over time. Pollution may take themany formforms. ofOne would is toxic substances (e.g.,such as oil, metals, plastics, [[pesticide]]s, [[persistent organic pollutant]]s, and industrial waste products),. Another is stressful conditions (e.g.,such as changes of [[pH]], [[Hypoxia (environmental)|hypoxia]] or anoxia, increased temperatures, excessive [[turbidity]], or changes of [[salinity]]),. or theThe introduction of [[Pathogen|pathogenic organisms]] is another. Contaminants may include [[organic compound|organic]] and [[inorganic]] substances. A common cause of [[thermal pollution]] is the use of water as a [[coolant]] by [[power plants]] and industrial manufacturers.

Control of water pollution requires appropriate [[infrastructure]] and management plans as well as legislation. [[Technology]] solutions can include improving [[sanitation]], [[sewage treatment]], [[industrial wastewater treatment]], agricultural [[wastewater treatment]], [[erosion control]], [[sediment control]] and control of [[urban runoff]] (including stormwater management).

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"."<ref name="Von Sperling"/>{{rp|6}} Water is typically referred to as polluted when it is impaired by [[human impact on the environment|anthropogenic]] contaminants. Due to these contaminants, it either no longer supports a certain human use, such as [[drinking water]], or undergoes a marked shift in its ability to support its biotic communities, such as fish.

* [[Disinfection by-product]]s found in chemically [[disinfection|disinfected]] [[drinking water]] (whilst these chemicals can be a pollutant in the [[Water distribution system|water distribution network]], they are fairly volatile and therefore not usually found in environmental waters).<ref>{{cite journal |vauthors=Alexandrou L, Meehan BJ, Jones OA |title=Regulated and emerging disinfection by-products in recycled waters |journal=[[The Science of the Total Environment]] |volume=637-638637–638 |pages=1607–1616 |date=October 2018 |pmid=29925195 |doi=10.1016/j.scitotenv.2018.04.391 |bibcode=2018ScTEn.637.1607A |s2cid=49355478}}</ref>

* [[Hormone]]s (from [[animal husbandry]] and residue from human [[hormonal contraception]] methods) and synthetic materials such as [[phthalate]]s that mimic hormones in their action. These can have adverse impacts even at very low concentrations on the natural biota and potentially on humans if the water is treated and utilized for drinking water.<ref>{{cite web |title=Environment Agency (archive) – Persistent, bioaccumulative and toxic PBT substances |url=http://www.environment-agency.gov.uk/business/444304/1290036/1290100/1290353/1294402/1311542/?version=1&lang=_e |archive-url=https://web.archive.org/web/20060804195610/http://www.environment-agency.gov.uk/business/444304/1290036/1290100/1290353/1294402/1311542/?version=1&lang=_e |archive-date=August 4, 2006 |access-date=2012-11-14 |publisher=[[Environment Agency (UK)]]}}</ref><ref>[http://planetearth.nerc.ac.uk/news/story.aspx?id=297 Natural Environmental Research Council – River sewage pollution found to be disrupting fish hormones] {{Webarchive|url=https://web.archive.org/web/20150427112251/http://planetearth.nerc.ac.uk/news/story.aspx?id=297 |date=April 27, 2015 }}. Planetearth.nerc.ac.uk. Retrieved on 2012-12-19.</ref><ref>{{cite web |title=Endocrine Disruption Found in Fish Exposed to Municipal Wastewater |url=http://toxics.usgs.gov/highlights/wastewater_fish.html |archive-url=https://web.archive.org/web/20111015161223/http://toxics.usgs.gov/highlights/wastewater_fish.html |archive-date=October 15, 2011 |access-date=2012-11-14 |publisher=[[US Geological Survey]] |location=Reston, VA}}</ref>

* Illnesses in new-born infants ([[Blueblue baby syndrome]] from [[nitrate]])

* [[Helminth eggs]]<ref name="Von Sperling"/>{{rp|55}}<ref name="World Health Organization">{{cite book |url=http://www.susana.org/en/resources/library/details/1004|title=Guidelines for the Safe Use of Wastewater, Excreta and Greywater, Volume 4 Excreta and Greywater Use in Agriculture |date=2006 |publisher=[[World Health Organization]] |isbn=924154685992-4-154685-9 |edition=third |location=Geneva}}</ref>

| colspan=3 style="text-align: left;" |* Sources of these pollutants are municipalhousehold and industrial wastewater, urban runoff, agricultural and pasturestormwater drainage from agricultural activitiesareas<ref name="Von Sperling" />{{rp|7}}

TheBacteria, majorviruses, groups[[protozoan]]s ofand pathogenic[[parasitic organismsworm]]s are: (a)examples bacteria,of (b)pathogens viruses,that (c)can protozoansbe andfound (d)in helminthswastewater.<ref name="Von Sperling"/>{{rp|47}} In practice, [[indicator organism]]s are used to investigate pathogenic pollution of water because the detection of pathogenic organisms in water sample is difficult and costly, because of their low concentrations. The indicators ([[indicator bacteria|bacterial indicator]]) of fecal contamination of water samples most commonly used are: total coliforms (TC), or fecal coliforms (FC), orthe latter also referred to as thermotolerant coliforms, E.such as ''[[Escherichia coli]]''.<ref name="Von Sperling"/>{{rp|4752–53}}

Pathogens can produce waterborne diseases in either human or animal hosts.<ref>{{Cite book |url=https://pubs.rsc.org/en/content/ebook/978-1-84973-648-0 |title=Pollution: Causes, effects, and control |date=2013 |publisher=[[Royal Society of Chemistry]] |vauthors=Harrison RM |editor-first1=R. M. |editor-last1=Harrison |isbn=978-1-78262-560-5 |edition=5th |location=Cambridge, UK |doi=10.1039/9781782626527 |oclc=1007100256}}</ref> Some microorganisms sometimes found in contaminated surface waters that have caused human health problems include: ''[[Burkholderia pseudomallei]],'' ''[[Cryptosporidium parvum]],'' ''[[Giardia lamblia]],'' ''[[Salmonella]],'' [[norovirus]] and other viruses, [[Helminths|and parasitic worms]] including the ''[[Schistosoma]]'' type.''<ref>Schueler, Thomas R. "Microbes and Urban Watersheds: Concentrations, Sources, & Pathways." Reprinted in [http://cwp.org/documents/cat_view/75-articles-from-the-practice-of-watershed-protection.html?limit=40&order=name&dir=DESC&start=80 ''The Practice of Watershed Protection.''] {{webarchive|url=https://web.archive.org/web/20130108194041/http://www.cwp.org/documents/cat_view/75-articles-from-the-practice-of-watershed-protection.html?limit=40&order=name&dir=DESC&start=80 |date=January 8, 2013}} 2000. Center for Watershed Protection. Ellicott City, MD.</ref>''

Organic substances that enter water bodies are often [[toxic]].<ref name="Laws-aquatic">{{cite book |vauthors=Laws EA |url=https://books.google.com/books?id=V5D2DQAAQBAJ |title=Aquatic Pollution<nowiki>:</nowiki> An Introductory Text |date=2018 |publisher=[[John Wiley & Sons]] |isbn=9781119304500978-1-119-30450-0 |edition=4th |location=Hoboken, NJ |via=[[Google Books]]}}</ref>{{rp|229}}

[[Per- and polyfluoroalkyl substances]] (PFAS) are [[persistent organic pollutant]]s.<ref name="ReferenceA">{{cite journal |vauthors = Johnson MS, Buck RC, Cousins IT, Weis CP, Fenton SE |title=Estimating Environmental Hazard and Risks from Exposure to Per- and Polyfluoroalkyl Substances (PFASs): Outcome of a SETAC Focused Topic Meeting |journal=[[Environmental Toxicology and Chemistry]] |volume=40 |issue=3 |pages=543–549 |date=March 2021 |pmid=32452041 |pmc=8387100 |doi=10.1002/etc.4784}}</ref><ref name="linkinghub.elsevier.com">{{cite journal |vauthors=Sinclair GM, Long SM, Jones OA |title=What are the effects of PFAS exposure at environmentally relevant concentrations? |journal=[[Chemosphere]] |volume=258 |pages=127340 |date=November 2020 |pmid=32563917 |doi=10.1016/j.chemosphere.2020.127340 |s2cid=219974801 |bibcode=2020Chmsp.258l7340S25827340S}}</ref>

* Salt: [[Freshwater salinization]] is the process of salty runoff contaminating [[freshwater ecosystem]]s.<ref name="Kaushal et al">{{cite journal |vauthors=Kaushal SS, Likens GE, Pace ML, Utz RM, Haq S, Gorman J, Grese M |title=Freshwater salinization syndrome on a continental scale |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=115 |issue=4 |pages=E574–E583 |date=January 2018 |pmid=29311318 |pmc=5789913 |doi=10.1073/pnas.1711234115 |bibcode=2018PNAS..115E.574K |doi-access=free}}</ref> Human-induced salinization is termed as secondary salinization, with the use of [[de-icing]] road salts as the most common form of runoff.<ref>{{cite journal |vauthors=Evans DM, Villamagna AM, Green MB, Campbell JL |title=Origins of stream salinization in an upland New England watershed |journal=[[Environmental Monitoring and Assessment]] |volume=190 |issue=9 |pages=523 |date=August 2018 |pmid=30116969 |doi=10.1007/s10661-018-6802-4 |bibcode=2018EMnAs.190..523E |s2cid=52022441}}</ref><ref name="Cañedo-Argüelles">{{cite journal |vauthors=Cañedo-Argüelles M, Kefford B, Schäfer R |title=Salt in freshwaters: causes, effects and prospects - introduction to the theme issue |journal=Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences |volume=374 |issue=1764 |date=December 2018 |pmid=30509904 |pmc=6283966 |doi=10.1098/rstb.2018.0002}}</ref>

* [[Environmental persistent pharmaceutical pollutant]]s, which can include various [[pharmaceutical drug]]s and their [[metabolite]]s (''see also'' [[drug pollution]]), such as [[antidepressant]] drugs, [[antibiotic]]s or the [[Oral contraceptive pill|contraceptive pill]].

* Metabolites of [[Illegal drug trade|illicit drugs]] (see also [[Wastewater-based epidemiology|wastewater epidemiology]]), for example [[methamphetamine]] and [[MDMA|ecstasy.]]<ref name="journals.biologists.com">{{Cite journal |vauthors=Knight K |date=2021 |title=Freshwater methamphetamine pollution turns brown trout into addicts |url=https://journals.biologists.com/jeb/article/224/13/jeb242971/270754/Freshwater-methamphetamine-pollution-turns-brown |journal=[[Journal of Experimental Biology]] |volume=224 |issue=13 |pages=jeb242971 |doi=10.1242/jeb.242971 |issn=0022-0949 |doi-access=free}}</ref><ref name="De Lorenzo">{{Cite web |last=De Lorenzo |first=D |title=MDMA Gangs Are Literally Polluting Europe |url=https://www.vice.com/en/article/qj83jw/mdma-gangs-are-literally-polluting-europe |date=2021-06-18 |website=Vice World News |publisher=[[Vice Media Group]] |location=Brooklyn, NY}}</ref>

Microplastics persist in the environment at high levels, particularly in [[Aquatic ecosystem|aquatic]] and [[marine ecosystem]]s, where they cause water pollution.<ref name=":9">{{Cite web |title=Development solutions: Building a better ocean |url=https://www.eib.org/en/essays/plastic-pollution |access-date=2020-08-19 |website=European Investment Bank}}</ref> 35% of all ocean microplastics come from textiles/clothing, primarily due to the erosion of polyester, acrylic, or nylon-based clothing, often during the washing process.<ref>{{Cite web |vauthors=Resnick B |date=2018-09-19 |title=More than ever, our clothes are made of plastic. Just washing them can pollute the oceans |url=https://www.vox.com/the-goods/2018/9/19/17800654/clothes-plastic-pollution-polyester-washing-machine |access-date=2021-10-04 |website=[[Vox (website)|Vox]]}}</ref>

Stormwater, untreated sewage water (96%) and wind (4%), are the primary conduits for microplastics from land to sea. Synthetic fabrics, tyres, and city dust are the most common sources of microplastics. These three sources account for more than 80% of all microplastic contamination.<ref name=":0">{{Cite journal web|last=Bank |firstauthor=((European Investment Bank))|date=2023-02-27 |title=Microplastics and Micropollutants in Water: Contaminants of Emerging Concern |url=https://www.eib.org/en/publications/20230042-microplastics-and-micropollutants-in-water |language=EN|access-date=2024-04-12}}</ref><ref>{{Cite web |title=Microplastics from textiles: towards a circular economy for textiles in Europe — European Environment Agency |url=https://www.eea.europa.eu/publications/microplastics-from-textiles-towards-a |access-date=2023-03-24 |website=www.eea.europa.eu |language=en}}</ref>

As of 2022, [[Europe]] and [[Central Asia]] account for around 16% of global microplastics[[microplastic]]s discharge into the seas.<ref>{{Cite journal |last=Ritchie |first=Hannah |last2=Roser |first2=Max |date=2018-09-01 |title=Plastic Pollution |url=https://ourworldindata.org/plastic-pollution |journal=Our World in Data}}</ref>,<ref name=":0" /><ref>{{Cite web |last=Ferris |first=Robert |title=Half of plastic trash in oceans comes from 5 countries |url=https://www.cnbc.com/2016/01/13/half-of-plastic-trash-in-oceans-comes-from-5-countries.html |access-date=2023-03-24 |website=CNBC |date=January 13, 2016 |language=en}}</ref> and although management of plastic waste and [[plastic recycling|its recycling]] is improving globally, the absolute amount of plastic pollution continues to increase unabated due to the large amount of plastic that is being produced and disposed of.<ref name=ritchie2023>{{Cite journal|last1=Ritchie |first1=Hannah|author1-link=Hannah Ritchie |last2=Samborska|first2=Veronika|last3=Roser |first3=Max |author3-link=Max Roser |year=2023|title=Plastic Pollution |url=https://ourworldindata.org/plastic-pollution |journal=Our World in Data|access-date=12 April 2024}}</ref> Even if sea plastic pollution were to stop entirely, microplastic contamination of the surface ocean would be projected to continue to increase.<ref name=ritchie2023/>

[[File:Brayton Point Power Station.JPG|thumb|The [[Brayton Point Power Station]] in Massachusetts dischargesdischarged heated water to [[Mount Hope Bay]] until 2011.]]

The introduction of aquatic [[Invasive species|invasive organisms]] is a form of water pollution as well. It causes [[biological pollution]].<ref>{{cite journal |vauthors=Olenin S, Minchin D, Daunys D |title=Assessment of biopollution in aquatic ecosystems |journal=[[Marine Pollution Bulletin]] |volume=55 |issue=7–9 |pages=379–394 |date=2007 |pmid=17335857 |doi=10.1016/j.marpolbul.2007.01.010|bibcode=2007MarPB..55..379O }}</ref>

Sewage typically consists of 99.9% water and 0.1% solids.<ref>{{cite book |vauthors=Scholz M |title=Wetlands for Water Pollution Control |year=2016 |isbn=9780444636072978-0-444-63607-2 |pages=13–15 |chapter=Sewage Treatment |doi=10.1016/B978-0-444-63607-2.00003-4}}</ref> Sewage contributes many classes of nutrients that lead to eutrophication[[Eutrophication]]. It is a major source of phosphate for example.<ref name="WPC2">{{cite book |title=Water Pollution Control |year=2014 |isbn=9781118863831978-1-118-86383-1 |veditors=Nesaratnam ST |doi=10.1002/9781118863831}}</ref> Sewage is often contaminated with diverse compounds found in personal [[hygiene]], [[cosmetics]], [[pharmaceutical drug]]s (see also [[drug pollution]]), and their metabolites<ref>{{Cite journal |vauthorsname=Knight K |date=2021 |title=Freshwater methamphetamine pollution turns brown trout into addicts |url=https://"journals.biologists.com"/jeb/article/224/13/jeb242971/270754/Freshwater-methamphetamine-pollution-turns-brown |journal=[[Journal of Experimental Biology]] |volume=224 |issue=13 |pages=jeb242971 |doi=10.1242/jeb.242971 |issn=0022-0949 |doi-access=free}}</ref><ref name="De Lorenzo"/> Water pollution due to environmental persistent pharmaceutical pollutants can have wide-ranging consequences. When sewers overflow during storm events this can lead to water pollution from untreated sewage. Such events are called [[sanitary sewer overflow]]s or [[Combined sewer|combined sewer overflows]].[[File:AngleseyCopperStream.jpg|thumb|upright|A polluted river draining an abandoned [[copper mine]] on [[Anglesey]]]]

Industrial processes that use water also produce wastewater. This is called [[Industrial wastewater treatment|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.<ref name=Eckenfelder/> Some industries discharge chemical wastes, including solvents and heavy metals (which are toxic) and other harmful pollutants.

* [[Organic material|Organic]] matter and nutrients such as [[food waste]]: Certain industries (e.g. [[food processing]], [[slaughterhouse]] waste, paper fibers, plant material, etc.) discharge high concentrations of BOD, ammonia nitrogen and oil and grease.<ref>{{Cite book |url=https://www.worldcat.org/oclc/48053912 |title=Wastewater engineering: treatment and reuse |date=2003 |publisher=McGraw-Hill |vauthors=Tchobanoglous G, Burton FL, Stensel HD |isbn=0-07-041878-0 |edition=4th |location=Boston |chapter=Chapter 3: Analysis and Selection of Wastewater Flowrates and Constituent Loadings |oclc=48053912}}</ref>{{rp|180}}<ref name="Laws-aquatic" />

* [[Pharmaceuticals]], endocrine disrupting compounds, hormones, perfluorinated compounds, siloxanes, drugs of abuse and other hazardous substances<ref name="pmid25889547">{{cite journal |vauthors=Arvaniti OS, Stasinakis AS |title=Review on the occurrence, fate and removal of perfluorinated compounds during wastewater treatment |journal=[[The Science of the Total Environment]] |volume=524-525524–525 |issue= |pages=81–92 |date=August 2015 |pmid=25889547 |doi=10.1016/j.scitotenv.2015.04.023 |bibcode=2015ScTEn.524...81A}}</ref><ref name="pmid23320453">{{cite journal |vauthors=Bletsou AA, Asimakopoulos AG, Stasinakis AS, Thomaidis NS, Kannan K |title=Mass loading and fate of linear and cyclic siloxanes in a wastewater treatment plant in Greece |journal=[[Environmental Science & Technology]] |volume=47 |issue=4 |pages=1824–32 |date=February 2013 |pmid=23320453 |doi=10.1021/es304369b |bibcode=2013EnST...47.1824B |s2cid=39997737}}</ref><ref name="pmid27236142">{{cite journal |vauthors=Gatidou G, Kinyua J, van Nuijs AL, Gracia-Lor E, Castiglioni S, Covaci A, Stasinakis AS |title=Drugs of abuse and alcohol consumption among different groups of population on the Greek Island of Lesvos through sewage-based epidemiology |journal=[[The Science of the Total Environment]] |volume=563-564563–564 |issue= |pages=633–40 |date=September 2016 |pmid=27236142 |doi=10.1016/j.scitotenv.2016.04.130 |bibcode=2016ScTEn.563..633G |hdl=10067/1345920151162165141|s2cid=4073701 |hdl-access=free }}</ref>

* [[Microplastics]] such as polyethylene and polypropylene beads, polyester and polyamide<ref name="pmid30620926">{{cite journal |vauthors=Gatidou G, Arvaniti OS, Stasinakis AS |title=Review on the occurrence and fate of microplastics in Sewage Treatment Plants |journal=[[Journal of Hazardous Materials]] |volume=367 |issue= |pages=504–512 |date=April 2019 |pmid=30620926 |doi=10.1016/j.jhazmat.2018.12.081 |bibcode=2019JHzM..367..504G |s2cid=58567561}}</ref>

[[Carbon dioxide in Earth's atmosphere|Carbon dioxide concentrations in the atmosphere]] have increased since the 1850s due anthropogenic influences ([[Greenhouse gas emissions|emissions of greenhouse gases]]).<ref name="cald03" /> This leads to [[ocean acidification]] and is another form of water pollution from atmospheric contributions.<ref>{{cite journal |vauthors=Doney SC, Fabry VJ, Feely RA, Kleypas JA |title=Ocean acidification: the other CO2 problem |journal=[[Annual Review of Marine Science]] |volume=1 |issue=1 |pages=169–192 |date=2009-01-01 |pmid=21141034 |doi=10.1146/annurev.marine.010908.163834 |bibcode=2009ARMS....1..169D|s2cid=402398 }}</ref>

The use of a biomonitor or [[bioindicator]] is described as [[Biomonitoring|biological monitoring]]. This refers to the measurement of specific properties of an organism to obtain information on the surrounding physical and chemical environment.<ref name=":22">{{Cite report |date=March 2016 |title=National Rivers and Streams Assessment 2008-20092008–2009: A Collaborative Study |url=https://www.epa.gov/sites/production/files/2016-03/documents/nrsa_0809_march_2_final.pdf |publisher=EPA |id=EPA 841/R-16/007}}</ref> Biological testing involves the use of plant, animal or microbial indicators to monitor the health of an [[aquatic ecosystem]]. They are any biological species or group of species whose function, population, or status can reveal what degree of ecosystem or environmental integrity is present.<ref name="Karr">{{cite journal |vauthors=Karr JR |year=1981 |title=Assessment of biotic integrity using fish communities |journal=Fisheries |volume=6 |issue=6 |pages=21–27 |doi=10.1577/1548-8446(1981)006<0021:AOBIUF>2.0.CO;2 |bibcode=1981Fish....6f..21K |issn=1548-8446}}</ref> One example of a group of bio-indicators are the [[copepod]]s and other small water [[crustacean]]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.

Water pollution is a major global [[environmental problem]] because it can result in the degradation of all [[aquatic ecosystem]]s – fresh, coastal, and ocean waters.<ref name="HäderHelblingVillafañe2021">{{cite book |author1=Donat-P. Häder |author2=E. Walter Helbling |author3=Virginia E. Villafañe |date=30 September 2021 |title=Anthropogenic Pollution of Aquatic Ecosystems |publisher=Springer Nature |isbn=978-3-03030-07560275602-4 |url=https://books.google.com/books?id=ZtxFEAAAQBAJ |access-date=9 August 2022 |page=1 |quote=Pollution is a major stress factor affecting all aquatic ecosystems including fresh, coastal and open ocean waters.}}</ref> The specific contaminants leading to pollution in water include a wide spectrum of [[chemical]]s, pathogens, and physical changes such as elevated temperature. While many of the chemicals and substances that are regulated may be naturally occurring ([[calcium]], [[sodium]], iron, [[manganese]], etc.) the [[concentration]] usually determines 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 manhuman-made chemicals. Other natural and anthropogenic substances may cause turbidity (cloudiness) which blocks light and disrupts plant growth, and clogs the [[gill]]s of some fish species.<ref name="Davies-ColleySmith2001">{{cite journal |last1=Davies-Colley |first1=R. J. |last2=Smith |first2=D. G. |title=Turbidity, Suspended Sediment and Water Clarity: A Review |journal=Journal of the American Water Resources Association |date=October 2001 |volume=37 |issue=5 |pages=1085–1101 |issn=1093-474X |eissn=1752-1688 |doi=10.1111/j.1752-1688.2001.tb03624.x |bibcode=2001JAWRA..37.1085D |s2cid=129093839 |url=https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1752-1688.2001.tb03624.x |access-date=9 August 2022}}</ref>[[File:Dumping of faecal sludge into the river.jpg|thumb|[[septage|Fecal sludge]] collected from pit latrines is dumped into a river at the Korogocho slum in [[Nairobi, Kenya]].]]

A study published in 2017 stated that "polluted water spread [[gastrointestinal disease]]s and [[Parasitic disease|parasitic infections]] and killed 1.8&nbsp;million people" (these are also referred to as waterborne diseases).<ref>{{cite news |vauthors=Kelland K |date=2017-10-19 |title=Study links pollution to millions of deaths worldwide |publisher=Reuters |url=https://www.reuters.com/article/us-health-pollution/study-links-pollution-to-millions-of-deaths-worldwide-idUSKBN1CO39B}}</ref> Persistent exposure to pollutants through water are [[environmental health]] hazards, which can increase the likelihood for one to develop cancer or other diseases.<ref>Dovjak, Mateja; Kukec, Andreja (2019), "Health Outcomes Related to Built Environments", ''Creating Healthy and Sustainable Buildings'', Cham: Springer International Publishing, pp. 43–82, [[Doi (identifier){{doi|doi]]:10.1007/978-3-030-19412-3_2}}, [[{{ISBN (identifier)|ISBN]] [[Special:BookSources/978-3-030-19411-6|<bdi>978-3-030-19411-6</bdi>]]}}, [[{{S2CID (identifier)|S2CID]] 190160283, retrieved 2022-08-10}}</ref>

For example, [[water pollution in India]] and [[Water resources of China|China]] is wide spreadwidespread. About 90 percent of the water in the cities of China is polluted.<ref>{{cite news |url=http://www.chinadaily.com.cn/english/doc/2005-06/07/content_449451.htm |title=China says water pollution so severe that cities could lack safe supplies |work=China Daily |date=June 7, 2005}}</ref>{{world topic|Water pollution in|title=Water pollution by country|noredlinks=yes|state=expand}}

One aspect of environmental protection areis mandatory regulations, but theywhich are only part of the solution. Other important tools in pollution control include environmental education, economic instruments, market forces, and stricter enforcementsenforcement. 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]] (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.<ref name="Jones OA et al">{{Cite book |vauthors=Jones OA, Gomes RL |editor-first1=R. M. |editor-last1=Harrison |url=https://pubs.rsc.org/en/content/ebook/978-1-84973-648-0|title=Pollution: Causes, Effects and Control|publisher=Royal Society of Chemistry |year=2013 |isbn=978-1-84973-648-0 |edition=5th|chapter=Chapter 1: Chemical Pollution of the Aquatic Environment by Priority Pollutants and its Control|doi=10.1039/9781782626527 }}</ref>

Municipal wastewater can be treated by centralized sewage treatment plants, [[decentralized wastewater system]]s, [[nature-based solutions]]<ref name=":2">UN-Water (2018) [http://www.unwater.org/publications/world-water-development-report-2018/ World Water Development Report 2018: Nature-based Solutions for Water], Geneva, Switzerland</ref> or in [[Onsite sewage facility|onsite sewage facilities]] and septic tanks. For example, [[waste stabilization pond]]s arecan be a low cost treatment option for sewage, particularly for regions with warm climates.<ref name="Von Sperling">{{Cite journal |last=Von Sperling |first=Marcos |date=2007 |title=Wastewater Characteristics, Treatment and Disposal |urljournal=https://www.iwapublishing.com/books/9781843391616/wastewater-characteristics-treatment-and-disposalWater Intelligence Online |journalpublisher=IWA Publishing|series=Biological Wastewater Treatment|volume=6 |doi=10.2166/9781780402086 |isbn=9781780402086978-1-78040-208-6 |doi-access=free}} [[File:CC-BY_icon.svg|50x50px]] Text was copied from this source, which is available under a [[creativecommons:by/4.0/|Creative Commons Attribution 4.0 International License]]</ref>{{rp|182}} UV light (sunlight) can be used to degrade some pollutants in waste stabilization ponds (sewage lagoons).<ref>{{cite journal |vauthors=Wang Y, Fan L, Jones OA, Roddick F |title=Quantification of seasonal photo-induced formation of reactive intermediates in a municipal sewage lagoon upon sunlight exposure |journal=[[The Science of the Total Environment]] |volume=765 |pages=142733 |date=April 2021 |pmid=33572041 |doi=10.1016/j.scitotenv.2020.142733 |s2cid=225156609 |bibcode=2021ScTEn.765n2733W76542733W}}</ref> The use of [[safely managed sanitation service]]s would prevent water pollution caused by lack of access to sanitation.<ref name="JMP2017" />

Well-designed and operated systems (i.e., with secondary treatment stages or more advanced tertiary treatment) can remove 90 percent or more of the [[Measures of pollutant concentration|pollutant load]] in sewage.<ref>{{cite report |title=Primer for Municipal Wastewater Treatment Systems |url=https://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=20017KBE.txt |date=2004 |publisher=[[EPA]] |page=11 |id=EPA 832-R-04-001}}</ref> Some plants have additional systems to remove [[nutrient]]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]].<ref>{{cite journal |vauthors=Jones OA, Green PG, Voulvoulis N, Lester JN |title=Questioning the excessive use of advanced treatment to remove organic micropollutants from wastewater |journal=[[Environmental Science & Technology]] |volume=41 |issue=14 |pages=5085–5089 |date=July 2007 |pmid=17711227 |doi=10.1021/es0628248 |bibcode=2007EnST...41.5085J}}</ref>

[[Sanitary sewer overflow|Sewer overflows]] during storm events can be addressed by timely maintenance and upgrades of the [[Sewerage|sewerage system]]. In the US, cities with large combined systems have not pursued system-wide separation projects due to the high cost,<ref>{{cite web |vauthors=Renn AM |title=Wasted: How to Fix America's Sewers |url=https://media4.manhattan-institute.org/sites/default/files/R-AR-0216.pdf |date=2016-02-25 |page=7 |publisher=Manhattan Institute |location=New York, NY}}</ref> but have implemented partial separation projects and [[green infrastructure]] approaches.<ref>{{cite report |title=Greening CSO Plans: Planning and Modeling Green Infrastructure for Combined Sewer Overflow Control |url=https://www.epa.gov/sites/production/files/2015-10/documents/greening_cso_plans_0.pdf |date=March 2014 |publisher=[[EPA]] |id=832-R-14-001}}</ref> In some cases municipalities have installed additional CSO storage facilities<ref>{{cite web |url=https://www.dcwater.com/clean-rivers-projectcleanrivers |title=Clean Rivers Project |author=<!--Not stated--> |publisher=[[District of Columbia Water and Sewer Authority]] |location=Washington, DC |access-date=20212024-0904-2113}}</ref> or expanded sewage treatment capacity.<ref>{{cite web |title=United States and Ohio Reach Clean Water Act Settlement with City of Toledo, Ohio |url=http://yosemite.epa.gov/opa/admpress.nsf/b1ab9f485b098972852562e7004dc686/59f70abeaacc274885256c24005e6240?OpenDocument |date=2002-08-28 |publisher=EPA |archive-url=https://web.archive.org/web/20160113095352/http://yosemite.epa.gov/opa/admpress.nsf/b1ab9f485b098972852562e7004dc686/59f70abeaacc274885256c24005e6240?OpenDocument |archive-date=2016-01-13 |id=Press release.}}

* {{sectionlinksection link|Environmental impact of pesticides|Water}}

{{Library resources box |by=no |onlinebooks=no |others=yes lcheading=Water --– Pollution}}

* [https://www.unep.org/explore-topics/water/what-we-do/tackling-global-water-pollution Tackling global water pollution] -– UN Environment Programme