Implications of (micro)plastics: from environmental impacts to policy considerations

Prof. Denise M. Mitrano, partment of Environmental Systems Science,
E-mail contact: denise.mitrano@usys.ethz.ch

Numerous studies have made the ubiquitous presence of plastic in the environment undeniable, and thus it no longer comes as a surprise when scientists measure the accumulation of macroplastic litter and microplastic fragments in both urban and remote sites. Ultimately, the different physical and chemical characteristics of the different size classes of plastic pollution (macroplastic, microplastic and nanoplastic) will result in divergent fate and hazards. Analytical difficulties to detect (nano- and micro)plastics in complex matrices are challenging to overcome, and thus mechanistic studies to understand the fate, transport and biological interactions of these materials are limited. While progress is still ongoing to develop protocols to measure particulate plastic in field studies, researchers who study these processes in bench top or pilot scale studies can take advantage of an entirely different approach. In the last years, we have synthesized a variety of particulate plastics with an embedded inorganic fingerprint which can be used as a proxy to detect plastic by common analytical techniques for trace metals analysis. In practice, this affords for quicker and more accurate sampling and subsequently allows us to investigate the basic processes and pathways which control particulate plastic fate and impacts in the environment and hazards to biota. We have used these materials in a number of different test systems including in aquatic, terrestrial and biological contexts, which will be discussed. We also address how the presence of plastics in the environment can impact natural environmental conditions; such as changing nutrient transport cycles and green-house gas emissions. Work must strive to capture the complexity of this contaminant suite and the broad diversity of impacts at all ecological scales. The presence of plastic in the environment has sparked considerable discussion amongst scientists, regulators and the general public as to how industrialization and consumerism is shaping our world. Restrictions on the intentional use of primary microplastics are under discussion globally, and there are incentives to replace certain plastics in some contexts, which can stimulate innovation of new, more competitive and environmentally conscious materials. Balancing the needs of next generation plastics will also be discussed. Collectively, our research aims to understand the implications of (nano- and micro)plastics in the environment and provide information to make more sound and sustainable choices in relation to plastic use and waste management.