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Investigation into the Levels of Environmental Contaminants in Scottish Marine and Freshwater Fin-Fish and Shellfish


Food contamination can occur due to chemicals present in the environment. Some occur naturally whilst others result from historical industrial activities, global or local pollution. In 2006 the FSA published data on ‘Dioxins and PCBs in wild and farmed fish and shellfish’ and ‘BFRs in farmed and wild fish, shellfish and fish oils’. These surveys included some Scottish samples but not all species of deep sea fish or fish caught and consumed by anglers from freshwater courses, sea lochs and estuaries.<P>
This project identified Scottish fishing grounds or aquatic habitats with a history of exposure to environmental contamination and the edible species of fish and shellfish that they support. Suitable samples of fish and shellfish were taken from selected locations c and analysed for environmental chemicals including metals, dioxins, polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), brominated flame retardants (BFRs), perfluorinated compounds (PFCs), polychlorinated naphthalenes (PCNs) and phthalates.

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Research Approach:<BR> A desk study was carried out to identify habitats that support edible species of fish and shellfish and rank them according to their risk of contamination by environmental contaminants. Samples of fish and shellfish were collected from those habitats identified as having the highest risk of contamination. Samples were then analysed for levels of heavy metals, dioxins, PCBs, PAHs, BFRs, PFCs, napthalenes and phthalates.
Results and Findings:<BR>This report represents the first study of such a comprehensive set of contaminants in fish and as such is unique.

A range of fish species from marine and freshwater habitats were obtained comprising 32 marine samples, 16 freshwater samples and 5 marine shellfish samples. These were analysed for the array of organic and inorganic contaminants. <P>

The results of this study confirm the occurrence of a wide range of environmental contaminants in these species and underline the ubiquity and persistence of these compounds. This is evident from the occurrence of both legacy contaminants (like PCNs and PCBs), as well as more recently introduced chemicals (such as brominated diphenylethers and PFCs).

Freshwater fish generally showed higher levels of the main contaminants investigated than marine species or shellfish(except for arsenic and mercury). However it is important to note that, for the organic contaminants, no fish or shellfish samples in this study breached the existing regulatory limits. The same was observed for the heavy metals, with some minor excursions beyond the maximum limits for mercury in ling and blue ling which were expected. The higher results in freshwater species suggest that these are more susceptible to localised pollution effects.

A parallel study on freshwater fish from unmanaged waterways in other parts of the UK is currently underway. The combined information from these two sets of complementary data may allow more refined estimates of human exposure.

<p>Find more about this project and other FSA food safety-related projects at the <a href="; target="_blank">Food Standards Agency Research webpage</a>.

FERA - Food and Environment Research Agency
Marine Scotland
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