Methods for monitoring of pellets and mesoplastic fragments on Dutch beaches

Four Dutch beaches were chosen to apply the monitoring method. The OSPAR beach selection criteria were used (2022). In addition, the proximity to sources (harbour or estuary outlet) was used as an additional beach selection criterion (Galgani et al., 2023). This led to the selection of the locations Neeltje Jans (close to the outlet of the Westerschelde estuary and indicated as pellet hotspot) and Monster (close to the outlet of the Nieuwe Waterweg and to the port of Rotterdam). Terschelling and Bergen, both national monitoring locations for beach litter, were also selected. These two beaches are standard monitoring locations for beach macro litter.