Particulate plastics (nano- and microplastic particles; size < 5µm) are an extremely persistent pollutant in the environment. As a consequence, it is highly likely that even with a better management of plastic waste, their concentrations in the environment will continue to increase. These small particulate plastics have a higher bioavailability than large plastic debris and are therefore presumed to be even more hazardous to ecosystem health. However, there is currently little information on the fate, transport and bioavailability of particulate plastics in water bodies, especially in fresh waters. Importantly, systematic knowledge on their potential to interact with freshwater organisms and to impact food-webs is largely lacking.
In this line of research we focus on key interactions and processes that determine bioavailability, bioaccumulation and toxicity of particulate plastics in a simplified food chain in streams. Specifically, we use stream periphyton communities and aquatic snails feeding on periphyton as primary producers and a primary consumer, respectively. By combining analytical chemistry and biology approaches, we aim (1) to examine the interactions and processes driving fate of particulate plastics in complex freshwater environments such as streams, (2) to better understand how particulate plastics impact diversity, composition and functions of microbial communities in periphyton, and (3) to decipher the mechanisms underlying effects of particulate plastics on the aquatic grazers Physa acuta through dietary exposure.