Pilot project: Microplastics in Dutch marine sediments – method testing

In this pilot project, we explored several method options for the monitoring of microplastics in marine sediments. This project was performed by the NIVA microplastic laboratory in Oslo, Norway, for the first time.
Several method options (from NIVA and a modified Cefas method) were compared. Results indicate that additional cleanup of samples is needed, in particular of calcium-containing particles like foraminifera shells. Furthermore, the cleanup of organic material still needs to be improved, also because smaller filters are used for FTIR analysis which can be covered more easily by remaining natural particles.
Silicon filters were tested and appeared to give improved spectral results in the infrared fingerprint range. The use of smaller filters improved the efficiency of the FTIR analysis, and subsequent data analyses by a factor of four.
Data analysis using siMPle showed that sufficiently high polymer threshold values must be used, in order to avoid false positive identifications.