Plastic pollution is clearly a mammoth problem. Indeed, along with phosphorous pollution, the United Nations Environment Programme (UNEP - mentioned in my previous post on Eutrophication) lists plastic pollution in the oceans as one of the two main emerging issues in its 2011 Year Book (UNEP 2011).
The more I read about plastic pollution in the literature, the more I realised I could not tackle the issue in one post alone - there's simply too much information. As a result, I have decided to break down all this info into bite size chunks beginning with...
MICROPLASTICS (part 1):
As the name suggests, microplastics [Figure 1] are characterised by their small size. However, there seems to be no common consensus in the literature regarding a size "limit". For example, UNEP defines microplastics as plastic fragments measuring less than 5 millimeters in length (ibid), whereas Browne et al. (2007) consider them to be less than 1mm. Gregory and Andrady (2003, in Andrady 2011) place microplastic in the micrometer (μm) range, with anything big enough to pass through a 500μm sieve but small enough to be caught in a 67μm sieve, i.e. any plastic between approx. 0.06 and 0.5mm.
|Figure 1. Microplastics on a petri dish (Sea Education Association)|
My next post will cover the sources of microplastics and some of these may surprise you - at least they did me - so stayed tuned!