Research landscape of a global environmental challenge: Microplastics.

Microplastics can be found all over the world, in the remotest regions and even in the Arctic snow. Primary microplastic is either produced as microparticles or enters the natural environment already as microparticles. Whereas secondary microplastic is generated by fragmentation or abrasion of other products in the natural environment. Both pollute the global ecospheres and even enter the human food chain. This study aims at the evaluation of the global publication output on both types of microplastic referring to absolute and contextual numbers. Only since 2006, the focus on the environmental burden led to an enormous increase of publications on MP. While China, USA and Germany are leading players regarding the absolute numbers, Portugal, Chile and Ireland are among the top countries when including socio-economic features and research expenditures. The responsibility for the big plastic waste producers can be shown by significantly correlating numbers of articles and the plastic waste generation, albeit here China and USA fall behind. However, the biggest producers are not the most affected countries. Despite the strong international interest, our study shows that many countries play no role at all in the publication landscape of MP. For future planning, it is necessary to extend the international collaborations to reach sustainable solutions for the whole planet earth.