ROCCH, the french monitoring network carried out by Ifremer,  surveys chemical contaminants levels in coastal areas through two programmes, mussel watch programme and  sediment watch programme. In 2019, surface sediment samples were collected along french coast between Dunkerque harbour and Saint Michael Mount Bay for metallic and organic pollutants analyses. Chemical contaminant were analysed in whole sediment and co - factors like aluminium and organic carbon were simultaneously measured for normalisation procedures.