World's Dirtiest Rivers and Lakes

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Mouth of the Matanza-Riachuelo River Buenos Aires Photo
6 of 15

While small compared to the others on this list (only 65 miles), the Matanza-Riachuela River, running through the heart of Buenos Aires, is referred to as the largest open pit toilet in the world, absorbing over 325,000 tons of sewage each day. Lead, mercury, cadmium, nitrates and copper all pollute this river and affect drinking water supplies for the over 5 million people living in the area.

Mouth of the Matanza-Riachuelo River in Buenos Aires. Image via: FJTU on Flickr.com