Surface debris were collected with a metal trowel over a square of 1 m² within a historical accumulation zone of plastic debris. They were collected in one shot close to the Seine river mouth (North France; 49.46452, 0.43911), the 28th of february 2020. Plastic debris higher than 6 mm were sorted and classified using the updated international MSFD and OSPAR classifications, joined as the J-list. They were then counted, weighed and data were reported in a csv file. Those data help identifying historical plastic pollution and its sources for future mitigation policies.

Figure showing the sampling localization. A, map of the Seine estuary with the sampling site (yellow star) and plastic producers (red stars). B, the sampled square meter. C, plastic debris collected and sorted in glass jars. D, plastic preproduction pellets. E, unidentified fragments 2.5 cm. Plastic debris classified by numb and by count according to the J-list (https://publications.jrc.ec.europa.eu/repository/handle/JRC121708).