EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Sediment trapping as a method for monitoring microplastic flux rates and deposition at aquatic environments

Saija Saarni1, Samuel Hartikainen2, Emilia Uurasjärvi2, Senja Meronen3, Jari Hänninen4, Maarit Kalliokoski3,5, and Arto Koistinen2
Saija Saarni et al.
  • 1Ecosystems and Environment Research Programme, University of Helsinki, Helsinki, Finland (
  • 2SIB Labs, University of Eastern Finland, Kuopio, Finland
  • 3Department of Geography and Geology, University of Turku, Turku, Finland
  • 4Archipelago Reseach Station, University of Turku, Turku, Finland
  • 5Institute of Earth Sciences, University of Iceland, Reykjavik, Iceland

Microplastics are reported from wide range of aquatic environments with concentrations up to thousands of particles per kilogram of sediment. Due to a lack of temporal control, evaluation of the influx rate of microplastic pollution is not enabled. However, understanding the annual flux rate of microplastics to the aquatic environments is a crucial aspect for environmental monitoring and for risk assessment. A sediment trap method is widely applied in aquatic sedimentary studies in order to measure sedimentation rates and understand sedimentation processes. We have tested near-bottom sediment trap method in lacustrine and estuary environments, at central and coastal Finland, for measuring and quantifying the microplastic influx rate during one year. Near-bottom sediment traps with two collector tubes and known surface area, fixed one meter from the bottom, collect all particles that are about to accumulate on the basin floor of the water body. Controlled temporal interval of trap maintenance enables calculation and determination of local microplastic influx rate i.e. number of accumulating particles per time per surface area. The test results are very promising.  Near-bottom sediment traps can be used for long term monitoring in order to gain a deeper understanding of the microplastic transport and sedimentation processes, confirm and compare the feasibility and efficiency of different environmental conservation methods, setting threshold values for microplastic influx, and supervising that the defined target conditions are met.

How to cite: Saarni, S., Hartikainen, S., Uurasjärvi, E., Meronen, S., Hänninen, J., Kalliokoski, M., and Koistinen, A.: Sediment trapping as a method for monitoring microplastic flux rates and deposition at aquatic environments , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-18444,, 2020