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]], with a negative impact on their 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-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 may affect either [[surface water]] or [[groundwater pollution|groundwater]]. This form of pollution can lead to many problems. One is the [[environmental degradation|degradation]] of [[aquatic ecosystems]]. Another 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> Water pollution also reduces the [[ecosystem service]]s such as [[drinking water]] provided by the [[Water resources|water resource]].

Sources of water pollution are either [[point source]]s or [[non-point source]]s.<ref>{{Cite journal |lastlast1=Schaffner |firstfirst1=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 Thethe 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. An example is [[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 many forms. One would is toxic substances such as oil, metals, plastics, [[pesticide]]s, [[persistent organic pollutant]]s, and industrial waste products. Another is stressful conditions such as changes of [[pH]], [[Hypoxia (environmental)|hypoxia]] or anoxia, increased temperatures, excessive [[turbidity]], or changes of [[salinity]]). The 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).

Bacteria, viruses, [[protozoan]]s and [[parasitic worm]]s are examples of pathogens that can be found in wastewater.<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), the latter also referred to as thermotolerant coliforms, such as ''[[Escherichia coli]]''.<ref name="Von Sperling"/>{{rp|52-5352–53}}

* 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>

As of 2022, [[Europe]] and [[Central Asia]] account for around 16% of global [[microplastic]]s discharge into the seas,<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/>

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=978-0-444-63607-2 |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=978-1-118-86383-1 |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" />

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 can be a low cost treatment option for sewage.<ref name="Von Sperling">{{Cite bookjournal|last=Von Sperling |first=Marcos |date=2007 |title=Wastewater Characteristics, Treatment and Disposal |journal=Water Intelligence Online |publisher=IWA Publishing|series=Biological Wastewater Treatment|volume=6 |doi=10.2166/9781780402086 |isbn=978-1-78040-208-6 |doi-access=free}}</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.76542733W}}</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>

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