ROCCH is the french marine chemical monitoring network, divided in two parts : superficial sediment monitoring (ROCCHSED) and molluscs monitoring (ROCCHMV). It mesures chemical contaminants concentration (trace metals, organic pollutants).

In sediments, monitoring cycles imply 300 to 400 stations visited every 6 years during yearly oceanographic campaigns. Till now, ROCCHSED program include 3 completed cycles, for which the most recents campaigns are :

• East Channel in 2013 ;
• Bay of Biscaye in 2014 ;
• West Channel in 2015 ;
• Mediterranean sea in 2016 ;
• Mediterranean lagoons in 2017.

The 4th ROCCHSED cycle started with the 2019 ROCCHSED campaign in East Channel. Chemical analysis concern trace metals and organic pollutants considered for marine environmental protection, especially under international regulations (OSPAR convention, Barcelone Convention, European directives as water framework Directive WFD and marine strategy framework Directive MSFD ) : Hg, Cd, Pb, Zn, Cu, Ni, Cr, Ag, organochlorines (DDT, DDD, DDE, lindane, HCH), polychlorobiphenyls (number 28, 52, 101, 105, 118, 138, 153, 180), Polycyclic aromatic hydrocarbons (Naphtalene, Fluorene, Phenantrene, Anthracene, Acenaphtene, Acenaphtylene, Fluoranthene, Pyrene, Benzo(a)anthracene, Chrysene, Benzo(a)pyrene, Dibenzo(a,h)anthracene, Benzo(b)fluoranthene, Benzo(k)fluoranthene, Benzo(g,h,i)perylene, Indeno(1,2,3-cd)pyrene), organotins, with measurement of co-factors (grain size fractions, aluminium, lithium, organic carbon) to normalize concentrations for comparisons between observed data and to assement criteria.

New pollutants are included in the monitoring according to regulation evolution, such as polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDDs) introduced in 2014, as well bioassay (ecotoxicological test on oysters larvae) introduced in 2019. Microplastics detection on selected stations was realised in 2020 and 2021 campaigns.

Chemical Analysis are realised in the upper 1cm of sediment, after sieving (<2 mm) and freeze-drying. A part of each freeze-dried sample is stored in the ROCCH sample bank and can be available for further research works.