First of all, humans need to stop adding more and more pollutants into the water system. This is a very important and current subject that needs to be taken seriously by companies polluting water systems, but also by the average consumer who purchases and uses products containing chemical pollutants. Not only do you not want these products on (or in) your body, they are terrible for the planet and for wildlife.
That said, these tiny plastic particles, micobeads, in particular are directly contributing to water pollution and the endangerment of fresh-water and marine wildlife, and what's worse is that they are specifically designed to be washed down the drain! Aside from simply filling water systems with tiny bits of plasic, these small plastic chemical pollutants are often confused as fish eggs by fish and other marine wildlife who eat them thinking they are food. Thus, the plastics are making their way into the food chain. Many environmentalists are calling for a ban of the use of these plastic particles and products containing them. New York, for example, is poised to be the first state to ban microbead scrubs, with California likely to follow suit.
Do your part to keep these plastics out of our water systems and out of the food chain by not purchasing products which contain microbeads or any microbead plastic exfoliant. Read the ingredients and do not use products containing plastics - often labelled simply as "PE", "PP" or "PMMA" in the product ingredients, also look for polyethylene and polypropylene and avoid these ingredients as well.
And if simply using plastic on your face and polluting water and fish doesn't bother you, think about the long term effects on the food chain, as fish eat plastic and bigger fish and other animals eat the fish, eventually these plastics will be making their way on to your own plate and into your stomach!
Read this article for more on this subject, and/or do a search engeine search for "microbead ban" for much more information on the subject. In the meantime, discontinue your use of products containing these harmful ingredients...and please share this information with others!
Article on the proposed ban of microbeads by The New York Times: http://www.nytimes.com/2014/02/11/nyregion/ban-sought-on-microbeads-in-beauty-items.html?_r=0