http://www.newsweek.com/plastic-pollution-has-infested-pristine-antarctic-fjords-similar-level-open-1026178

In the middle of the last century, mass-produced, disposable plastic waste started washing up on shorelines, and to be found in the middle of the oceans. This has since become an increasingly serious problem, spreading globally to even the most remote places on Earth. Just a few decades later, in the 1970s, scientists found the same problem was occurring at a much less visible, microscopic level, with microplastics.

These particles of plastic are between 0.05mm and 5mm in size. Larger pieces of plastic can be broken down into microplastics but these tiny bits of plastic also come from deliberate additions to all sorts of products, from toothpaste to washing power.