What are microplastics, where do they come from, and why are they a problem? Why are they so difficult to remove from the environment?
Dana Kühnel: Microplastics are either intentionally produced or formed by degradation and fragmentation of larger plastic items (primary and secondary microplastics). They are released into the environment by uncontrolled disposal of plastic waste and distributed widely through all environmental compartments. Principally, all living organisms should be able to live in an environment free of any pollution from human sources. Plastics litter of all size ranges is, however, widely distributed in all environmental compartments from the atmosphere to deep sea sediment.
For plastics, two additional factors make their wide appearance problematic: their persistency, as they degrade extremely slowly, and the additional distribution of various chemicals in the environment, as they contain various additives and other non-intentionally added substances. Furthermore, plastic is also subject to weathering processes, leading to the release of degradation products. Their mobility allows the transport from sources to all compartments, and hence exposure to various organisms. At the same time, removal of plastic pollution is impossible due to the small size of micro and nano-plastic particles, and their wide distribution, making them unavailable for any remediation efforts.
Microplastics have been found in the human body (in blood, in arterial plaques), what are the health risks of this? Are these materials a risk to other organisms and the wider environment as well?
Dana Kühnel: Health impacts of microplastic pollutions on humans are so far unknown, and for my understanding studies detecting microplastic in the human body need to be carefully considered regarding proper study design and application of detection techniques. To my knowledge, many studies are lacking proper controls, so that the option of cross contamination of samples by the ever-present plastic in our surroundings (background contamination of labs) cannot be ruled out. Hence, the findings so far need to be carefully re-assessed. In addition, there is a need for epidemiological studies, including cohort studies, to gain knowledge on health impacts. Certain additives in plastic products for vulnerable groups have been proven to be hazardous for humans (e.g. BPA in baby plastic bottles or toys)
There is currently no comprehensive EU law tackling microplastics, although tackling microplastic pollution is encompassed by the objectives of several laws and strategies (e.g., REACH amendment banning added microplastics; Strategy for Plastics in a Circular Economy; Zero Pollution Action Plan target of 30% reduction) – do you think EU measures are sufficient? What more could be done at the European level?
Dana Kühnel: Plastic pollution and also plastic use needs to be reduced on all possible levels we can influence. Furthermore, plastic production and use needs to take substantial steps towards circularity, and that does not mean only recycling. Proper recycling strategies are only one building block of a circular economy, and it is clear that we also need to cut the use of fossil fuels to reduce the release of greenhouse gasses. Therefore more development towards plastic products produced from natural resources are needed. So far, European Regulation is focussing on the restriction of single-use plastic, which is good, but far not enough to face the serious problem plastic pollution represents.
You work on science communication to communicate the environmental impacts of nanomaterials to wider audiences – why is this important? Are there steps at the individual level that can be taken to combat microplastic pollution?
Dana Kühnel: Communication of scientific results to the society and specifically to consumers on potential hazard of various technically produced materials is key to take informed decisions. Each individual can take steps to reduce plastic pollution: firstly, the avoidance of single-use plastics products and proper disposal, but most importantly a long use-phase for all plastic containing products (e.g. cars, smart phones…). Repairing is always better than recycling, as it keeps resources longer in the use-phase, whereas recycling of plastics is always down-cycling, resulting in plastics of reduced quality.