Raman microspectroscopic identification of microplastic particles in freshwater bivalves (Unio pictorum) exposed to sewage treatment plant effluents under different exposure scenarios
We investigated the uptake of microplastic (MP, <5 mm) particles by using freshwater bivalves (Unio pictorum) as biological samplers in the environment. They were exposed either directly to the biologically purified sewage of a North Bavarian sewage treatment plant (STP) or placed in a small river up- and downstream of the wastewater discharge for 28 days and 6 months, respectively. A control group was maintained in a pond. After acid digestion, the soft tissue was analyzed for MP particles by means of Raman microspectroscopy (RM, over 3000 particles individually measured), which allows for identification and quantification of particles down to 1 μm. Only in the bivalve collective exposed to STP effluents MP was found, however a very small amount (maximum of nine MP particles in the bivalve sample exposed for 6 months). In the bivalves up- and downstream of the wastewater discharge and in control organisms from a pond, no microplastic was identified. The amount of microplastic particles was small in absolute terms and small in relative terms (ca. 1:100 (6 months) and below 1:1000 (28 days)) as hundreds of particles per sample were analyzed which turned out to be non-plastic. Including the results for the river, this indicates a rather low MP contamination level for organisms in close vicinity to a sewage treatment plant.
KeywordsMicroplastic (MP) Aquatic environment Raman microspectroscopy (RM) Freshwater bivalve Sewage treatment plant (STP)
This work was funded by the Bavarian State Ministry of the Environment and Consumer Protection.
- Faure F, Corbaz M, Baecher H, De Alencastri LF (2012) Pollution due to plastics and microplastics in Lake Geneva and in the Mediterranean Sea. Arch Sci 65:157–164Google Scholar
- Fliedner A, Rudel H, Teubner D, Buchmeier G, Lowis J, Heiss C, Wellmitz J, Koschorreck J (2016) Biota monitoring and the water framework directive-can normalization overcome shortcomings in sampling strategies? Environ Sci Pollut Res Int 23:21927–21939. https://doi.org/10.1007/s11356-016-7442-2 CrossRefGoogle Scholar
- Leslie HA, van Velzen MJM, Vethaak AD (2013) Microplastic survey of the Dutch environment: novel data set of microplastics in North Sea sediments, treated wastewater effluents and marine biota. Institute for Enviromental Studies, VU Amsterdam, AmsterdamGoogle Scholar
- Lithner D (2011) Environmental and health hazards of chemicals in plastic polymers and products. A PhD Thesis, University of Gothenburg, Schweden ISBN: 978–91–85529-46-9Google Scholar
- Paulus M, Teubner D, Rüdel H, Klein R (2015) Bioaccumulation and long-term monitoring in freshwater ecosystems – knowledge gained from 20 years of Zebra mussel analysis by the German Environmental Specimen Bank. In: Armon RH, Hänninen O (eds) Environmental indicators. Springer Netherlands, Dordrecht, pp 781–803. https://doi.org/10.1007/978-94-017-9499-2_44 Google Scholar
- Titow WV (1984) Rigid PVC: main products – production, properties and applications. In: PVC technology, Fourth edn. Springer Netherlands, Dordrecht, pp 849–900. https://doi.org/10.1007/978-94-009-5614-8