Descriptor D9 relates the protection of human health to the state of the marine environment. It is closely connected to MSFD Descriptor 8, as both consider chemical contaminants, but has the specific scope of safeguarding of the marine environment as a source of human food supply.
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D9 Commission Decision (EU) 2017/848 of 17 May 2017
Contaminants in fish and other seafood for human consumption do not exceed levels established by Union legislation or other relevant standards.
Criteria
D9C1 – Primary: The level of contaminants in edible tissues (muscle, liver, roe, flesh or other soft parts, as appropriate) of seafood (including fish, crustaceans, molluscs, echinoderms, seaweed and other marine plants) caught or harvested in the wild (excluding fin-fish from mariculture) does not exceed: 
(a) for contaminants listed in Regulation (EC) No 1881/2006, the maximum levels laid down in that Regulation, which are the threshold values for the purposes of this Decision; 
(b) for additional contaminants, not listed in Regulation (EC) No 1881/2006, threshold values, which Member States shall establish through regional or subregional cooperation.
Glossary
The term contaminants in Descriptor 9 is interpreted as "substances for which regulatory levels have been set for human consumption or for which their presence in fish is relevant"1. Hazardous substances are substances (i.e. chemical elements and compounds) or groups of substances that are toxic, persistent and liable to bio-accumulate, and other substances or groups of substances which give rise to an equivalent level of concern. 

Fish and other seafood are interpreted as including fish, crustaceans, molluscs, echinoderms, and seaweed or plants caught or harvested in the wild as well as farmed shellfish in the different (sub) regions, which are destined for human consumption. This excludes farmed fish since their contaminant burden is linked to their feed and additives. 

Levels established by Community legislation are considered to be the regulatory levels set in European Community legislation for public health reasons. 

Other relevant standards are other national and international (e.g. WHO, FAO...) standards and recommendations set for substances and/or for fish and other seafood which are not covered by and are not in contradiction with the European legislation.