Microplastic in the Alpine water cycle – example of Austria

Plastic waste as a persistent contaminant of our environment is a matter of increasing concern due to the largely unknown long-term effects on biota. Although freshwater systems are known to be the transport paths of plastic debris to the ocean, most research has been focused on marine environments. In recent years, freshwater studies have advanced rapidly, but they rarely address the spatial distribution of plastic debris in the water column. A methodology for measuring microplastic transport at various depths that is applicable to large rivers was recently developed for the Danube River by consortium partners. However, plastic contamination in the Austrian mountains is not yet been addressed at all. Likewise, there is no information about possible biodegradation by microbes. Yet, river corridors represent one of the most used and modified landscape elements in the Alps. They provide key ecosystem services (ES), but currently many of them are at risk or significantly degraded. Alpine rivers and catchments play a key role for water supply and nature preservation. In order to ensure their conservation or restoration, the effects of human uses on the rivers and ES need to be understood and tackled. Hence Alplast aims - for the first time - to quantify plastic occurrence in the Austrian Alps, ranging from the glaciers at the top, over steep mountain channels to medium sized lowland rivers. In a multi-step approach, hot-spots will be identified to measure microplastic in relevant Alpine areas. For identified hot-spots, particle counts and concentrations will be elaborated for description of the most abundant plastic types in the Alpine environment. If microplastic finds its way to these areas, possible transport paths will be evaluated. Also, temporal changes of microplastic load in the snow cover will be tackled by taking snow samples in snow pits with 10 cm depth resolution. Effort will be undertaken to improve sample evaluation. Hence purified enzymes will be used for the removal of lignocellulose without affecting other materials like polyesters contained in microplastic aiming to reduce sample evaluation effort. Furthermore, potential microplastics degrading microbes will be identified based on knowledge about biodegradation of the respective synthetic polymers. Therefore, modern methods of metagenome analysis will be used for the discovery of even un-culturable microbes and their enzymes. This shall also allow a prediction of the fate of “biodegradable” microplastic in the respective regions in the future. An interdisciplinary team will address the different research questions involving experts in glaciology from University of Graz as well as experts in river monitoring from BOKU Vienna, Microbiologists from BOKU Vienna and the partner Umweltbundesamt for analysis.