Hannes K. Imhof, Alexandra C. Wiesheu, Philipp M. Anger, Reinhard
Niessner, Natalia P. Ivleva, Christian Laforsch,
Variation in plastic abundance at different lake beach zones – A case study,
Science of The Total Environment, Volumes 613–614, 1 February 2018,
Pages 530-537, ISSN 0048-9697
Plastic particles in marine and freshwater environments span from macroscopic to microscopic size classes. Each may have a different
impact on individuals, populations and ecosystems, but still the wide variety of methods used in beach sediment sampling inhibit comparisons among studies and therefore hampers a risk assessment. A large portion of the uncertainties is due to differing sampling strategies.
By quantifying the alongshore distribution of macro- and microplastic particles within five beaches of Lake Garda, we aim to shed light on the accumulation behavior of microplastic particles at an exemplary lake which might give indications for potential sampling zones.
The identification of plastic at the single particle level with a spatial resolution down to 1 μm was performed by Raman microspectroscopy. Given the time consuming approach we reduced the number of samples in the field but increased the spatial area where a single sample was taken, by utilizing a transect approach in combination with sediment cores (5 cmdepth).
The study revealed that, in comparison to the water line and the high-water line, the drift line of all five beaches always contained
plastic particles. Since the drift line accumulate particulate matter on a relatively distinct zone, it will enable a comparable sampling of
microplastic particles. The applied sampling approach provided a representative method for quantifying microplastic down to 1 μm on a
shore consisting of pebbles and sand. Hence, as first step towards a harmonization of beach sediment sampling we suggest to perform sampling at the drift line, although further methodological improvements are still necessary.