This visualization product displays marine litter material categories percentage per year per beach from 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

To calculate percentages, formula applied is : Material (%) = (∑number of items (normalized at 100 m) of each material category)/(∑number of items (normalized at 100 m) of all categories)*100

The material categories differ between reference lists. In order to apply a common procedure for all the surveys, the material categories have been harmonized.

Eleven material categories have taken into account for this product and information on data processing and calculation are detailed in the document attached p14.