This visualization product displays marine macro-litter (> 2.5cm) material categories percentage per beach per year from Marine Strategy Framework Directive (MSFD) monitoring surveys.
EMODnet Chemistry included the collection 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: in order to follow the approach of OSPAR that it is not including these data anymore in the monitoring;
- Selection of MSFD surveys only (exclusion of other monitoring, cleaning and research operations);
- Exclusion of beaches without coordinates;
- Some litter types like organic litter, small fragments (paraffin and wax; items > 2.5cm) and pollutants have been removed. The list of selected items is attached to this metadata. This list was created using EU Marine Beach Litter Baselines and EU Threshold Value for Macro Litter on Coastlines from JRC (these two documents are attached to this metadata);
- Exclusion of the "feaces" category: it concerns more exactly the items of dog excrements in bags of the OSPAR (item code: 121) and ITA (item code: IT59) reference lists;
- Normalization of survey lengths to 100m & 1 survey / year: in some case, the survey length was not exactly 100m, so in order to be able to compare the abundance of litter from different beaches a normalization is applied using this formula:
Number of items (normalized by 100 m) = Number of litter per items x (100 / survey length)
Then, this normalized number of items is summed to obtain the total normalized number of litter for each survey.
Sometimes the survey length was null or equal to 0. Assuming that the MSFD protocol has been applied, the length has been set at 100m in these cases.
To calculate percentages for each material category, formula applied is:
Material (%) = (?number of items (normalized at 100 m) of each material category)*100 / (?number of items (normalized at 100 m) of all categories)
The material categories differ between reference lists (OSPAR, ITA, TSG_ML, UNEP, UNEP_MARLIN). In order to apply a common procedure for all the surveys, the material categories have been harmonized.
More information is available in the attached documents.
Warning: the absence of data on the map doesn't necessarily mean that they don't exist, but that no information has been entered in the Marine Litter Database for this area.
