How Pollution is Effecting the World's Water

Everyone knows pollution has become a problem, but I would like to learn more about extreme examples, similar to the Great Pacific Garbage Patch

Above: is an image of an estimated 3.5 million ton island of plastic and garbage floating in the pacific ocean.

Below: shows the location of this island that is close to twice the size of Texas.

Below: A full hour long documentary on Garbage Island 

This is relatively new information to me, so i was curious if there were other extreme examples to learn about, and what we can do in order to alleviate these issues