http://www.miljodirektoratet.no/no/Publikasjoner/2015/Januar1/

http://www.miljodirektoratet.no/no/Publikasjoner/2015/Januar1/Sources-of-microplastic-pollution-to-the-marine-environment/

Sources of microplastic-pollution to the marine environment

The overall objective of this study ordered by the Norwegian Environment
Agency is to provide a good overview of the different sources
contributing to microplastic pollution both in Norway and globally. For
Norway, we also provide a first assessment of the type and amount of
microplastics each source contributes.
Importantly, we characterize the microplastic sources only at their
upstream origin, ideally just where the microplastic particles start
their ?life? as environmental pollutants, for example at ?the start of
the pipe?, on land or at sea.

http://www.miljodirektoratet.no/Documents/publikasjoner/M321/M321.pdf