Ohio River

==Ecology==
{{See also|Water pollution in the United States}}
The Ohio River as a whole is ranked as the most polluted river in the United States, based on 2009 and 2010 data. The more industrial and regional West Virginia/Pennsylvania tributary, the [[Monongahela River]], ranked 17th for [[water pollution]], behind 16 other American rivers.<ref>{{cite news |newspaper=[[Pittsburgh Business Times]] |title=Report: Ohio River most polluted in U.S. |access-date=April 24, 2012 |url=http://www.bizjournals.com/pittsburgh/blog/morning-edition/2012/03/report-ohio-river-most-polluted-in-us.html |date=March 23, 2012 |archive-date=April 25, 2012 |archive-url=https://web.archive.org/web/20120425233358/http://www.bizjournals.com/pittsburgh/blog/morning-edition/2012/03/report-ohio-river-most-polluted-in-us.html |url-status=live}}</ref> The Ohio again ranked as the most polluted in 2013, and has been the most polluted river since at least 2001, according to the Ohio River Valley Water Sanitation Commission (ORSANCO). The Commission found that 92% of toxic discharges were [[nitrates]], including farm runoff and waste water from industrial processes such as steel production. The Commission also noted mercury pollution as an ongoing concern, citing a 500% increase in mercury discharges between 2007 and 2013.<ref>{{cite news |last=Bruggers |first=James  |title = Ohio River again tops list for industrial pollution |url = https://www.usatoday.com/story/news/nation/2015/03/14/ohio-river-tops-list-industrial-pollution/24784863/ |newspaper = Louisville Courier Journal |access-date = March 12, 2019 |archive-date = October 23, 2021 |archive-url = https://web.archive.org/web/20211023223447/https://www.usatoday.com/story/news/nation/2015/03/14/ohio-river-tops-list-industrial-pollution/24784863/ |url-status = live}}</ref>

For several decades beginning in the 1950s, the Ohio River was polluted with hundreds of thousands of pounds of [[Perfluorooctanoic acid|PFOA]], a fluoride-based chemical used in making [[teflon]], among other things, by the [[DuPont]] chemical company from an outflow pipe at its [[Parkersburg, West Virginia]], facility.<ref name=NYT>{{cite news |last=Rich |first=Nathaniel |title=The Lawyer Who Became DuPont's Worst Nightmare |url=https://www.nytimes.com/2016/01/10/magazine/the-lawyer-who-became-duponts-worst-nightmare.html?_r=0 |newspaper=The New York Times |date=January 6, 2016 |access-date=March 3, 2017 |archive-date=January 9, 2016 |archive-url=https://web.archive.org/web/20160109110502/http://www.nytimes.com/2016/01/10/magazine/the-lawyer-who-became-duponts-worst-nightmare.html?_r=0 |url-status=live}}</ref>

The Ohio was listed among [[America's Most Endangered Rivers]] of 2023 on the heels of contamination from a [[East Palestine, Ohio, train derailment|high-profile train derailment]], and following years as one of the most polluted watersheds in the United States.<ref>{{cite news |last1=Giffin |first1=Connor |title=Ohio River listed as endangered. What that means and what can be done to help. |url=https://www.courier-journal.com/story/news/local/2023/04/20/american-rivers-names-ohio-as-nations-second-most-endangered-river/70127473007/ |access-date=August 8, 2023 |work=The Courier-Journal |date=April 20, 2023}}</ref>