EGU2020-22616
https://doi.org/10.5194/egusphere-egu2020-22616
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Field studies for detecting microplastic in environmental compartments and a novel tomography approach for analysis of undisturbed soil or sediment cores

Sascha Oswald, Lena Katharina Schmidt, Eva Bauer, and Christian Tötzke
Sascha Oswald et al.
  • Institute of Environmental Science and Geography, University of Potsdam, Potsdam, Germany

In recent years we all had to realize that plastics has not only been accumulating in the oceans, but as microplastics also has entered surface waters, soils and partly organisms in large numbers. Thus, as with other pollutants in the environment in the past, we need detection and monitoring methods for quantifying their distribution, fate and pathways. By that we can better understand where they are emitted, where they are present and what are the key mechanisms they undergo. However, this means a new challenge and need for novel approaches because they are different to other pollutants.  In one study we have monitored presence of microplastic particles and some of their properties in a surface water course and groundwater wells close the river banks, detecting them by a novel and fast imaging technique after processing of surface water samples. Furthermore, soil and sand samples from different places were separated by density and then manually analyzed, and the results indicated an extensive presence of microplastic particles. Finally, we have developed a tomography approach to detect microplastic particles also in undisturbed sandy soil or sediment samples. This has the advantage that cores can be taken and analyzed that show the real distribution of microplastic particles, and obtain also some information on their size and shape. Overall, this also can contribute to understand their deposition and displacement in the past. We will demonstrate how a combination of X-ray and neutron tomography could be used to identify microplastic particles non-invasively, for test samples as well as first environmental samples.

How to cite: Oswald, S., Schmidt, L. K., Bauer, E., and Tötzke, C.: Field studies for detecting microplastic in environmental compartments and a novel tomography approach for analysis of undisturbed soil or sediment cores, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-22616, https://doi.org/10.5194/egusphere-egu2020-22616, 2020

Comments on the presentation

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Presentation version 1 – uploaded on 02 May 2020
  • CC1: Comment on EGU2020-22616, Alexandra FOETISCH, 06 May 2020

    Dear Sacha,

    Thank you for this very interesting presentation. I am not familiar with tomography, thus I have some questions:

    • What parameters do you use to treshold and eliminate the bulk sand? Is it density?
    • I suppose sediment can contain a little amount of organic matter, how do you differenciate it from plastic?
    • What is the minimum size of the plastic particles you can detect with this method?
    • Does X-ray tomography allows to identify the polymer type?

    Best,

     

    Alexandra Foetisch

     

  • AC1: Comment on EGU2020-22616, Sascha Oswald, 06 May 2020

    Dear Alexandra,

    thanks for your questions. And no worries, also people familiar with tomography have asked some similar ones in the session chat.

    1. tresholding. Is based on attenuation for neutrons or X-rays (of the facility). In case of the latter this is related to density, but at least neutron attenuation is more specific to particular elements (and their isotopes).

    2. organic matter. One can try to degrade (a part of ) organic matter by chemical treatment beforehand. There may be more options to deal with remaining larger organic matter particles. It is also a matter of size. Organic matter much smaller than sediment graines will rather contribute to the background than being taken as microplastic particle.

    3. size of microplastic particles that can be detected. It worked well for microplastic particles of about one mm size, thus the largest size fraction of microplastic particles. The spatial resolution of the tomography methods is substantially finer, and thus it seems possible that also smaller microplastic particles can be detected, down to something like a few 100 micrometers. Needs to be explored. Even microplastic content of particles smaller than that could possibly be visualized, but not as individual particles.

    4. Polymer type. Not possible to identify by our tomography approach directly. But after the tomographies are done one could follow up with any destructive method, also in respect to identifying polymer type.

    Regards,
    Sascha