Microplastic contamination in an urban area: case of greater Paris

International audienceMicroplastics have been defined as particles < 5 mm. While the marine plastic pollution has been well documented, there has been limited focus on the continental contamination where their sources and their dynamics remain largely unknown. This study investigates the microplastic contamination of both urban compartments (wastewater and total atmospheric fallout) and surface water in continental environment. These first investigations on urban environment confirm the presence of microplastics in sewage, freshwater and total atmospheric fallout and provide knowledge on the type and size distribution of microplastics in the [100 – 5 000 µm] range.Whatever the matrix considered, microplastic were observed. For the first time, microplastics, mostly fibers, were found in atmospheric fallout (29 to 280 particles/m2/day). High levels of fibers are also found in wastewater (260-320 x103 particles/m3). In treated effluents, the contamination significantly decreases to 14-50 x103 particles/m3. No millimetric fiber was observed in treated effluent attesting to their removal. In river Seine, two sampling devices are used to collect both large and small microplastic particles: i) a plankton net (80 µm mesh) and ii) a manta trawl (330 µm mesh). Sampling with the plankton net shows a predominance of fibers with concentrations ranging from 3 to 108 particles/m3. A greater diversity of both microplastic shapes and types is encountered during manta trawl sampling but at much lower concentrations (0.28-0.47 particles/m3). This combined approach could be relevant and implemented in future studies to provide an accurate overview of microplastic distribution in freshwater