Editing Great Lakes (section)

===Pollution===
The first U.S. [[Clean Water Act]], passed by a Congressional override after being vetoed by U.S. President [[Richard Nixon]] in 1972, was a key piece of legislation,<ref>{{cite book |title = Evolution of the Great Lakes Water Quality Agreement |first1 = Paul |last1 = Muldoon |first2 = Lee |last2 = Botts |publisher = Michigan State University Press |year = 2005 }}</ref> along with the bi-national [[Great Lakes Water Quality Agreement]] signed by Canada and the U.S. A variety of steps taken to process industrial and municipal pollution discharges into the system greatly improved water quality by the 1980s, and Lake Erie in particular is significantly cleaner.<ref>{{cite web |url = http://www.michigan.gov/dnr/0%2C1607%2C7-153--145852--%2C00.html |archive-url = https://web.archive.org/web/20130830182201/http://www.michigan.gov/dnr/0%2C1607%2C7-153--145852--%2C00.html |archive-date = August 30, 2013 |title = Recovery of Lake Erie Walleye a Success Story |publisher = Michigan Department of Natural Resources |date = June 8, 2006 }}</ref> Discharge of toxic substances has been sharply reduced. Federal and state regulations control substances like [[Polychlorinated biphenyl|PCBs]]. The first of 43 "[[Great Lakes Areas of Concern]]" to be formally "de-listed" through successful cleanup was Ontario's Collingwood Harbour in 1994; Ontario's Severn Sound followed in 2003.<ref>{{cite web |work = binational.net |url = http://binational.net/ourgreatlakes/ourgreatlakes.pdf |archive-url = https://web.archive.org/web/20051227162745/http://binational.net/ourgreatlakes/ourgreatlakes.pdf |archive-date = December 27, 2005 |title = Our Great Lakes }}</ref> [[Presque Isle Bay]] in Pennsylvania is formally listed as in recovery, as is Ontario's Spanish Harbour. Dozens of other Areas of Concern have received partial cleanups such as the [[River Rouge (Michigan)|Rouge River (Michigan)]] and Waukegan Harbor (Illinois).<ref>{{cite web |url = http://www.epa.state.il.us/environmental-progress/v22/n1/waukegan-harbor.html |archive-url = https://web.archive.org/web/20141129040321/http://www.epa.state.il.us/environmental-progress/v22/n1/waukegan-harbor.html |archive-date = November 29, 2014 |title = Milestone in Waukegan Harbor PCB Cleanup |publisher = Illinois Environmental Protection Agency |date = Spring 1997 }}</ref>

Phosphate detergents were historically a major source of nutrient to the Great Lakes algae blooms in particular in the warmer and shallower portions of the system such as Lake Erie, [[Saginaw Bay]], [[Green Bay (Lake Michigan)|Green Bay]], and the southernmost portion of Lake Michigan. By the mid-1980s, most jurisdictions bordering the Great Lakes had controlled phosphate detergents.<ref>{{cite web |last = Knud-Hansen |first = Chris |date = February 1994 |url = http://www.colorado.edu/conflict/full_text_search/AllCRCDocs/94-54.htm |title = Historical Perspective of the Phosphate Detergent Conflict |archive-url = https://web.archive.org/web/20100528155811/http://www.colorado.edu/conflict/full_text_search/AllCRCDocs/94-54.htm |archive-date = May 28, 2010 |id = Working Paper 94-54 |via = Colorado.edu |access-date = December 7, 2016 }}</ref> Blue-green algae, or [[cyanobacteria]] blooms,<ref>{{cite web |url = https://www.weather.gov/cle/LakeErieHAB |title = Lake Erie Harmful Algal Bloom |publisher = National Weather Service }}</ref> have been problematic on Lake Erie since 2011.<ref>{{cite news |url = https://www.nytimes.com/2013/03/15/science/earth/algae-blooms-threaten-lake-erie.html |title = Spring Rain, Then Foul Algae in Ailing Lake Erie |date = March 14, 2013 |work = The New York Times }}</ref> "Not enough is being done to stop fertilizer and phosphorus from getting into the lake and causing blooms," said Michael McKay, executive director of the Great Lakes Institute for Environmental Research (GLIER) at the [[University of Windsor]]. The largest Lake Erie bloom to date occurred in 2015, exceeding the severity index at 10.5 and in 2011 at a 10.<ref name="windsorstar.com">{{cite news |url = https://windsorstar.com/news/local-news/large-lake-erie-algal-bloom-nearing-colchester-tested-for-toxicity |archive-url = https://web.archive.org/web/20190811140408/https://windsorstar.com/news/local-news/large-lake-erie-algal-bloom-nearing-colchester-tested-for-toxicity |archive-date = August 11, 2019 |title = Large Lake Erie algal bloom nearing Colchester tested for toxicity |work = Windsor Star |date = August 7, 2019 |first = Sharon |last = Hill |access-date = August 12, 2019 }}</ref> In early August 2019, satellite images depicted a bloom stretching up to 1,300 square kilometers on Lake Erie, with the heaviest concentration near [[Toledo, Ohio]]. A large bloom does not necessarily mean the cyanobacteria ... will produce toxins", said Michael McKay, of the University of Windsor. Water quality testing was underway in August 2019.<ref>{{cite news |url = http://www.uwindsor.ca/dailynews/2019-08-07/uwindsor-researchers-test-waters-harmful-algae-bloom |archive-url = https://web.archive.org/web/20190812145246/http://www.uwindsor.ca/dailynews/2019-08-07/uwindsor-researchers-test-waters-harmful-algae-bloom |archive-date = August 12, 2019 |title = UWindsor researchers test the waters for harmful algae bloom }}</ref><ref name="windsorstar.com" />

==== Mercury ====
Until 1970, [[Mercury (element)|mercury]] was not listed as a harmful chemical, according to the United States Federal Water Quality Administration. In the 21st century, mercury has become more apparent in water tests. Mercury compounds have been used in paper mills to prevent slime from forming during their production, and chemical companies have used mercury to separate chlorine from brine solutions. Studies conducted by the [[United States Environmental Protection Agency|Environmental Protection Agency]] have shown that when the mercury comes in contact with many of the bacteria and compounds in the fresh water, it forms the compound [[Methylmercury|methyl mercury]], which has a much greater impact on human health than elemental mercury due to a higher propensity for absorption. This form of mercury is not detrimental to a majority of fish types, but is very detrimental to people and other wildlife animals who consume the fish. Mercury has been known for health related problems such as birth defects in humans and animals, and the near extinction of eagles in the Great Lakes region.<ref>{{cite web |url = http://www.idph.state.il.us/envhealth/factsheets/mercuryspills.htm |title = Mercury Spills |publisher = Idph.state.il.us |access-date = February 19, 2011 }}</ref>

==== Sewage ====
The amount of raw sewage dumped into the waters was the primary focus of both the first Great Lakes Water Quality Agreement and federal laws passed in both countries during the 1970s. Implementation of secondary treatment of municipal sewage by major cities greatly reduced the routine discharge of untreated sewage during the 1970s and 1980s.<ref>{{cite web |url = http://ohioseagrant.osu.edu/_documents/publications/FS/FS-046%20Lake%20Erie%20water%20quality%20past%20present%20future.pdf |archive-url = https://web.archive.org/web/20060902100228/http://ohioseagrant.osu.edu/_documents/publications/FS/FS-046%20Lake%20Erie%20water%20quality%20past%20present%20future.pdf |archive-date = September 2, 2006 |url-status = live |title = Lake Erie Water Quality Past Present and Future |access-date = December 4, 2013 }}</ref> The [[International Joint Commission]] in 2009 summarized the change: "Since the early 1970s, the level of treatment to reduce pollution from waste water discharges to the Great Lakes has improved considerably. This is a result of significant expenditures to date on both infrastructure and technology, and robust regulatory systems that have proven to be, on the whole, quite effective."<ref name="ijc.org">{{Cite book |url = http://www.ijc.org/php/publications/pdf/ID1631.pdf |archive-url = https://web.archive.org/web/20100924165650/http://ijc.org/php/publications/pdf/ID1631.pdf |archive-date = September 24, 2010 |url-status = live |title = 14th Biennial Report on Great Lakes Water Quality }}</ref> The commission reported that all urban sewage treatment systems on the U.S. side of the lakes had implemented secondary treatment, as had all on the Canadian side except for five small systems.{{Citation needed|date=September 2012}}

Though contrary to federal laws in both countries, those treatment system upgrades have not yet eliminated [[combined sewer]] overflow events.{{citation needed|date=December 2013}} This describes when older sewerage systems, which combine storm water with sewage into single sewers heading to the treatment plant, are temporarily overwhelmed by heavy rainstorms. Local sewage treatment authorities then must release untreated effluent, a mix of rainwater and sewage, into local water bodies. While enormous public investments such as the [[Deep Tunnel]] projects in Chicago and [[Milwaukee]] have greatly reduced the frequency and volume of these events, they have not been eliminated. The number of such overflow events in Ontario, for example, is flat according to the International Joint Commission.<ref name="ijc.org"/> Reports about this issue on the U.S. side highlight five large municipal systems (those of Detroit, Cleveland, Buffalo, Milwaukee and [[Gary, Indiana|Gary]]) as being the largest current periodic sources of untreated discharges into the Great Lakes.<ref>{{cite web |url = http://healthylakes.org/press-releases/new-report-solving-region%E2%80%99s-sewage-crisis-will-create-jobs-restore-great-lakes/ |title = New Report: Solving Region's Sewage Crisis Will Create Jobs, Restore Great Lakes |archive-url = https://web.archive.org/web/20141129035802/http://healthylakes.org/press-releases/new-report-solving-region%E2%80%99s-sewage-crisis-will-create-jobs-restore-great-lakes/ |archive-date = November 29, 2014 |work = Healthylakes.org |date = August 9, 2010 |access-date = December 7, 2016 }}</ref>
[[File:Diatoms_through_the_microscope.jpg|thumb|upright=1.3|Diatoms of different sizes seen through the microscope. These minuscule [[phytoplankton]] are encased within a [[silicate]] [[cell wall]].]]

The fish of the Great Lakes have anti-depressant drugs meant for humans in their brains, which has caused concerns. The number of American adults who take anti-depressant drugs rose from 7.7% of all American adults in 1999–2002 to 12.7% in 2011–2014. As the anti-depressant drugs pass out of human bodies and through sanitation systems into the Great Lakes, this has resulted in fish in the Great Lakes with twenty times the level of anti-depressants in their brains than what is in the water, leading to the fish being exceedingly happy and hence less risk-averse, to the extent of damaging the fish populations.<ref name="The Economist">{{cite news |title = Antidepressants are finding their way into fish brains |url = https://www.economist.com/united-states/2018/02/08/antidepressants-are-finding-their-way-into-fish-brains |access-date = January 15, 2023 |newspaper = The Economist |date = February 8, 2018 }}</ref>

==== Plastic ====
Researchers have found that more than {{convert|22|e6lb}} of plastic end up in the Great Lakes each year.<ref name=agl>{{cite web |title = Great Lakes Plastic Pollution |url = https://greatlakes.org/great-lakes-plastic-pollution-fighting-for-plastic-free-water/ |access-date = April 21, 2023 |publisher = Alliance for the Great Lakes |language = en-US }}</ref> Plastics in the water break up into very small particles known as [[microplastics]]. Microplastics can also come from synthetic clothing washed down our drains.<ref name=varsity>{{cite news |first = Nicole |last = Szabo |date = September 5, 2021 |title = U of T researchers discover microplastics in all samples of Great Lakes fish |url = https://thevarsity.ca/2021/09/04/ontario-freshwater-microplastics-lakes/ |access-date = April 21, 2023 |website = The Varsity |language = en-US }}</ref> [[Plastic waste]] found in the lakes include [[single-use plastic]]s, plastics used in packaging, takeout containers as well as [[Plastic pellet pollution|pre-production pellets]] produced by [[plastics industry]].<ref>{{cite news |first1 = Inayat |last1 = Singh |first2 = Alice |last2 = Hopton |date = October 1, 2021 |title = Industrial plastic is spilling into Great Lakes, and no one's regulating it, experts warn |publisher = CBC News |url = https://www.cbc.ca/news/science/plastics-waste-great-lakes-water-1.6185621 |access-date = April 21, 2023 }}</ref> High concentrations of microplastics were discovered in 100 percent of the fish that were studied by researchers from the Rochman Lab. About {{convert|50|e6lb}} of fish is harvested each year from Great Lakes which has raised concerns on how this might affect human health.<ref name=varsity/> Microscopic pieces of plastic have also been found in drinking water coming from Great Lakes. It is estimated that nearly 40 million people in the region rely on drinking water from the Great Lakes.<ref name=agl/>

A number of self-operating floating devices called Seabin, were put in the Great Lakes to capture plastic trash as part of the Great Lakes Plastic Cleanup project. The project captured 74,000 pieces of trash using this technology between 2020 and 2021; however, it does not claim to catch up with {{convert|22|e6lb}} of plastic that ends up in Great Lakes every year. The production, consumption, and throwing away of plastics seems to remain the core of Great Lakes trash problem.<ref>{{Cite web |last = Redelmeier |first = Rebecca |date = October 14, 2022 |title = How a fleet of robots could help solve the Great Lakes plastic pollution problem |url = https://www.theverge.com/2022/10/14/23401381/great-lakes-plastic-pollution-cleanup-tech-robots |access-date = April 21, 2023 |website = The Verge |language = en-US }}</ref>