Bonk A., Dąbrowska A., Skawina A.

The presence of diverse plastic particles in aquatic environments and their influence on the ecosystems became a world-scale fact. Although the impact of plastics of different sizes on marine environments is under investigation for several years now, little is known about the presence and influence of these materials in freshwaters even if they are considered as likely places of original plastics’ load to the oceans. Several freshwater bivalve species were observed to be contaminated with microplastic fibres and spheres, however, there are currently no data on the presumable impact of this contact on plastic properties.

We treated adult Unio tumidus and Sphaerium sp. with the 20 μm polystyrene microspheres suspended in Scenedesmus algae for 2 hours. After this, bivalves were sacrificed, histological frozen sections were prepared and confocal microscopy used for analysis. Microspheres were detected in the intestine of both species, together with algae. Raman spectroscopy was used for acquiring spectra of both polystyrene spheres - suspended in algae and spheres from intestine content. Furthermore, we treated adult Unio tumidus with polystyrene nanoparticles (<20 nm). Although preliminary test on variants of sole polystyrene resulted in obtaining clear spectra, both bivalves’ induced samples: pre- and post- intestinal passage occurred as inaccessible for this method, but presumably for different reasons. The spectrum of spheres suspended in algae was presumably hidden in algae spectra, while particles from the intestine were likely precisely covered by the intestine content, which made access to the plastic and its measurement impossible. Nevertheless having in mind these difficulties we look for future methods of removal of biological contaminations to open the possibilities for testing the composition of the plastic particle in different moments of their passage through organisms and ecosystems.


Keywords: microplastic, freshwater, Unio tumidus, Sphaerium sp, Raman spectroscopy.


Acknowledgements: We are grateful to Barbara Pałys for the access to Raman spectroscopy, Piotr Maszczyk for sharing the microplastic sample, and to Piotr Bernatowicz for providing Scenedesmus algae suspension for these tests.


  1. Very nice poster! Interesting topic! Do you expect different behaviour for particles with irregular shape? What about fibers which are the most challenging micro-nanoplastics?

    1. Thank You. Yes, we certainly do. The subsequent experiments are already planned to check the influence of size, shape and a presence of functional groups. For a start. However, one thing is crucial here – the susceptible response parameter. Still validating what would be the best

  2. Hi,
    better to watch this in youtube at increased quality (over 720) resolution.
    Very nice study, good piece of science!
    How this particle size correspond to those found in the rivers inhabited by the species?

  3. Thank You for a comment!

    As for the question: although it would be more the topic for a long discussion (please feel invited for a one) than a short reply here, I will try:
    – so fare no knowledge available about the environmental presence of nanoplastics at this size as it is getting challenging more and more to monitor the debris in nature when size is below a few micrometers (+ all problems with self-contamination)
    – the fragmentation will lead to those (conclusion based on the results of laboratory aging experiments), so they are already or will be in the environment
    – the presence of micro debris of PS is confirmed in freshwaters and still increassing
    – the particles from scrubs (primary source of microplastics) fragment easily to nanosize

  4. Congratulations Agnieszka, very nice poster presentation! Thank you. If you are interested you can join the special disscussion room on microplastics effects on bivalves during special program at 17:35 at Room C led by Camilla Della Torre.

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