This visualization product displays plastic bags abundance per beach per year obtained during research & cleaning operations.

EMODnet Chemistry included the gathering of marine litter in its 3rd phase. Since the beginning of 2018, data of beach litter have been gathered and processed in the EMODnet Chemistry Marine Litter Database (MLDB). The harmonization of all the data has been the most challenging task considering the heterogeneity of the data sources, sampling protocols and reference lists used on a European scale. Preliminary processing were necessary to harmonize all the data : - Exclusion of OSPAR 1000 protocol, - Separation of monitoring surveys from research & cleaning operations - Exclusion of beaches with no coordinates - Normalization of survey lengths and survey numbers per year - Some categories & some litter types have been removed

Abundances have been calculated on each beach and year using the following computation: Plastic bags abundance=(∑number of plastic bags (normalized at 100m))/(Number of surveys on the year)

Percentiles 50, 75 & 95 have been calculated taking into account data from all years.

Plastic bags reference codes taken into account for this product and information on data processing (some normalization have been necessary) and calculation are detailed in the document attached p15.