Descriptor 9: Contaminants in Seafood
“Contaminants in fish and other seafood for human consumption do not exceed levels established by Community legislation or other relevant standards”
Marine fish and other seafood such as crustaceans, mollusks or seaweed constitute an important food source for human consumption.
Why should we pay attention to the contamination of fish and seafood?
Substances accumulating in an organism are likely to be transferred in the food chain, also referred to as biomagnification, a process where the concentration of a contaminant increases within the food chain. This has been observed for pesticides, which work their way into rivers and the marine environment from their use in agricultural practices, and which are then taken up by aquatic organisms, which are eaten by fish, which in turn are eaten by larger fish, birds, animals living on land or humans. Negative impacts on human health due to exposure to chemical components have been observed. An example is methylmercury, to which people can be exposed if they eat fish and shellfish which contain that substance. Exposure in the womb to methylmercury, from a mother's consumption of intoxicated fish or shellfish, can adversely affect a baby's growing brain and nervous system.
Important marine contaminants giving rise to concern and for which regulatory levels have been laid down (see box “Link to relevant European legislation") include organochlorine pesticides, organotin compounds, phthalates, brominated flame retardants, polyflourinated compounds, polycyclic aromatic hydrocarbons (PAH), dioxins, dioxin-like PCBs and non-dioxin-like PCBs, heavy metals (mercury, cadmium, lead), radionuclides and arsenic.
To achieve Good Environmental Status (GES), the Marine Directive says that the concentration of all contaminants should be below the maximum level set for human consumption, and preferably, should be declining. Indeed, concentrations of contaminants in fish and sea food, which are not in compliance with regulatory levels and which exceed them, are also indicators of bad environmental status.
What are the sources for the contamination of fish and seafood?
Contamination of marine organisms from human activities can come from many different sources, either from activities that are directly connected to the marine environment, such as accidental spills from offshore platforms, aquaculture and shipping lines, or from waste spread to the marine waters via land-based activities, such as agriculture or discharge from urban areas.
There are a number of contaminants in the marine environment which give rise to concern both from an environmental and a public health point of view.
These are contaminants which are known to bio-accumulate in marine organisms. Bioaccumulation occurs when an organism absorbs a toxic substance (from its environment or from dietary sources) at a rate greater than that at which the substance is lost, leaving the organism with a high internal concentration. Thus, the slower the rate of decomposition of the toxic substance the greater the risk of chronic poisoning, even if environmental levels of the toxin are not very high.
What can be done?
Similarly to Descriptor 8, some measures can reduce the number of compounds, sources and waste of contaminants. The EU REACH Regulation (Registration, Evaluation, Authorisation and Restriction of Chemical substances), which was introduced in 2007, aims to improve the protection of human health and of the environment through better and earlier identification of the intrinsic properties of chemical substances.
Under the REACH regime, manufacturers and importers are required to gather information on the properties of their chemical substances and to register the information. The Regulation also calls for the progressive substitution of the most dangerous chemicals when suitable alternatives have been identified. By registering and limiting the use of dangerous chemicals in the industrial production chain, REACH will indirectly reduce the contamination of marine waters and marine organisms by toxic substances, hence decrease the risk of contamination of fish and seafood for human consumption.