Our waterways are versatile, but the colossal amount of toxins legally dumped on a yearly basis may surprise you.

In just one year, American waterways were filled with 206 million pounds of toxic chemicals, according to a report conducted by the Environment America Research and Policy Center. The report, Wasting Our Waterways, cites the mid-Atlantic, Ohio River and South Atlantic-Gulf Coast watershed regions as the most polluted, with more than 20 million pounds of toxicity released into each of those waterways.

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Environment America, a non-profit advocacy group that relies on citizen donations and foundation grants to perform these studies, notes in the 72-page report that Indiana leads the nation in total releases with more than 17 million pounds of toxic chemicals released into its waterways in 2012, the most recent year in which data is available.

It's important to note that these toxic dumps are done legally and are monitored by the U.S.Environmental Protection Agency. Each company is required to declare how much toxic material will be dumped, and the EPA will monitor each corporation to ensure they're not exceeding their limit.

Below is an interactive map that shows how much each state contributes to the final total.

The EPA requires companies to report how much toxic chemicals they will release using the agency's ToxicsRelease Inventory program. From there, the data is made publicly available so groups like Environment America can compile reports like Wasting Our Waterways.

The report was released as the EPA was set to enact new lawsto protect another two million miles of waterwayswith Clean Water Act requirements, Nature World News reports. Oct. 18 will mark the42ndanniversary of the Clean Water Act becoming law.

This is the third time Environment America has conducted a study of toxic dumping since 2007, the year the group was founded, Rumpler told weather.com.

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