Where are America's most toxic watersheds that harm human health and the environment?
Despite the United States passing a Clean Water Act nearly 50 years ago to dramatically reduce pollution and restore America's waterways, toxic substances are still dumped into many water sources, threatening the health of people and ecosystems.
Industrial facilities discharged 193 million pounds of toxic substances into U.S. waterways in 2020, according to a report by the advocacy group Environmental America Research and Policy Center.
Meanwhile, industrial and government facilities polluted about 1 in 3 local watersheds nationwide with toxic substances, the report found. A watershed is defined by the EPA as a land area that drains to one stream, lake or river affecting the nearby water's quality.
These toxic substances are linked to severe health problems. The report found that 1 million pounds of chemicals were linked to cancer, 4.5 million pounds had the potential to affect the development of children and fetuses, and 200,000 pounds could potentially cause reproductive problems.
Although releases happen nationwide, people who swim in, eat the inhabitants of, or drink near watersheds that "receive particularly large discharges of chemicals" may be more vulnerable, the report states.
Drinking water, in particular, is an area of concern.
A 2021 analysis by the Environmental Working Group found that the drinking water supplies serving roughly 60 million Americans were contaminated with elevated levels of nitrate compound chemicals, which are linked to a variety of severe health risks, including effects on development, blood and fatal births defects.
Animal processing plants and petroleum refiners are the largest sources of nitrate compounds, which also spur toxic algae blooms in lakes, rivers and oceans that can kill fish and other animals.
The report from Environmental America Research and Policy Center lists the 10 facilities that are responsible for releasing the most toxic substances into waters from creeks to continental-scale rivers in 2020.
Of note, the watershed that saw the greatest amount of toxins released into its waters was the Lower Ohio-Little Pigeon watershed in Indiana and Kentucky.
The majority of the 12 million pounds of toxic discharge released into areas of the Ohio River stemmed from the Cleveland-Cliffs Rockport Works steel plant in Rockport, Indiana, which released nearly 11 million tons of nitrates into the river, according to the Environmental America Research and Policy Center.
Top 10 watersheds in US with most toxins
Here's a list of the 10 watersheds and locations in the U.S. that saw the greatest amount of toxic chemicals released into its waters in 2020, according to the the Environmental America Research and Policy Center:
Lower Ohio-Little Pigeon
Toxics released:12,008,366 lbs.
States: Indiana, Kentucky
Toxics released: 10,266,141 lbs.
States: North Carolina, Tennessee, Virginia
Toxics released: 6,191,362 lbs.
States: Delaware, Maryland, Pennsylvania
Lower Cape Fear
Toxics released: 5,017,810 lbs.
State: North Carolina
Toxics released: 4,640,523 lbs.
Lower Big Sioux
Toxics released: 4,507,539 lbs.
States: Iowa, Minnesota, Nebraska, South Dakota
Toxics released: 3,866,978 lbs.
Toxics released: 3,784,822 lbs.
Toxics released: 3,524,720 lbs.
States: Indiana, Kentucky, Ohio
Toxics released: 3,069,016 lbs.
States: Illinois, Wisconsin
The companies listed in this report — APC Polytech LLC, Radford Army Ammunition Plant, Rio Tinto (owners of Kennecott Utah Copper Mine), The Chemours Company, Nucor Steel Marion Inc., Duke Energy, Lonza Companies (owners of Arch Wood Protection Inc.), CPS Energy — did not immediately respond to a request for comment.
Where are the most harmful chemicals found?
Environmental America Research and Policy Center's report also broke down the locations with the most chemicals that cause cancer, reproductive or developmental damage in 2020, based on the EPA's Risk-Screening Environmental Indicators tool that calculates the weights of chemical releases based on their toxicity to humans.
Toxic substances released in waterways — which include highly toxic pollutants like lead, chloroform and dioxin-like compounds — may cause damage to the heart, cardiovascular system, brain, eyes, kidneys, liver, respiratory and more, according to the group's report.
• South Carolina, Texas and Alabama: These states had the most cancer-causing toxins in their waterways, released mostly by paper and pulp mills.
• Texas, Indiana and Pennsylvania: Waterways here saw the most toxins that affect reproductive health, discharged by fossil fuel power plants and iron and steel mills.
• North Carolina, Wisconsin and Alabama: These states saw the largest amount of developmental toxic releases known to interfere with the body's growth and changes, particularly impacting the health of adolescents and fetuses. Pulp, paper and paperboard mills were the largest releasers.
More USA TODAY stories to read
Confusion, bravery, awe: What happened after train derailed in East Palestine, Ohio
Red tide is flaring up in Florida: How safe is it to eat fish and other seafood?
How sugar substitutes stack up: Erythritol, sucralose and aspartame
Camille Fine is a trending visual producer on USA TODAY's NOW team.
What's everyone talking about? Sign up for our trending newsletter to get the latest news of the day
This article originally appeared on USA TODAY: Waters that contain the most toxic chemicals to humans and environment