Microplastics in the environment and organisms

Hardly a day goes by without a report about finding microplastics in different parts of the world from Antarctica to Amazon, different organisms from bacteria to whales, and different tissues from blood to brain. The amounts found naturally vary, but the particles are ubiquitous. With increasing use of plastics, the amounts found in different places naturally increase, but part of the increase can be attributed to development of detection methods. The methods available ten years ago would have left much of what is found today undetected.

The media attention to microplastics is alarmist. They are reported to cause health effects even when the data available do not allow such conclusions to be made. In fact, there are several problems in being able to conclude that microplastics really cause harm. The first is that most studies indicating harmful effects have been done with microplastics concentrations vastly exceeding the concentrations in the environment. The second is that studies normally use spherical shape of microplastic particles, whereas the environmental microplastic contamination contains all sorts of shape. The third is that the organismal differences are seldom taken into account. Finally, and personally I think this is the most important question of all: it may be that the plastic particle itself is inert, but being hydrophobic, acts as a vehicle – trojan horse – for hydrophobic toxicants to enter tissues. I would really like to see conclusive studies addressing this question. At least Katja Anttila’s group at the University of Turku, Finland is carrying out studies on this.

My musings of microplastic pollution were prompted by Richard C. Thompson et al. review in Science (Sept. 19): Twenty years of microplastics pollution research—what have we learned? (Science DOI: 10.1126/science.adl2746)