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PCBs and organochlorine pesticides in shrimp from the Belgian North Sea

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Brown shrimp © Misjel Decleer.

Context of the study

During the last century organochlorine pesticides and PCBs have been widely distributed in the environment. They are persistent, meaning they are hard to break down, they bioaccumulate and biomagnify and are toxic. Concern about this combination of characteristics makes that these substances are routinely monitored in marine organisms since the 1980s. (Other studies on organochlorines: bethic species, algae and harbour porpoises) [1]


Content of the study

This study determined PCB and organochlorine pesticide concentrations in shrimp sampled between 1994 and 2004 in the Belgian part of the North Sea.


Main results of the study

Brown shrimp © Hans Hillewaert
PCB content averaged 3.4 µg/kg in the 10 year period. This is well below the Belgian threshold for consumption of fishery products (75 µg/kg). This is mostly because of the low fat content of shrimp (1,6%). On a wet weight basis (meaning the concentration of contaminants in the whole sample) a decrease in PCB concentrations was observed over the 10 year period. However, on a lipid weight basis (meaning the concentration of contaminants in the lipids) no trend was observed. So, the reduced PBC concentration on a wet weight basis was probably caused by a reduced lipid content in the shrimp in recent years. The study therefore concluded that the PCB content of the Belgian part of the North Sea didn't improve significantly in the 10 year period.

The composition of the PCBs did change during the monitoring period. The amount of PCBs with many chlorine atoms, increased relatively to the amount of PCBs with few chlorine atoms. This was, because the latter are more volatile and will be enriched in cold areas like the Arctic. This effect can be observed if the PCB content of an area doesn't change. The latter is therefore an indication that the ban on the use and production of PCBs is effective.

Most organochlorine pesticides were not detectable, or were present at low concentrations. DDT was found to be mainly present in its degradation products DDE and DDD. This indicates that no new (or very small) contaminations of DDT have happened in the Belgian North sea in recent years.[1]

References

  1. 1,0 1,1 Raemaekers, M.; Derveaux, S.; Parmentier, K. (2006). Polychlorinated biphenyls and organochlor pesticides in brown shrimp (Crangon crangon) of the Belgian Continental Shelf, in: Luten, J.B. et al. (Ed.) (2006). Seafood research from fish to dish: quality, safety and processing of wild and farmed fish. pp. 489-496
The main author of this article is Daphnis De Pooter
Please note that others may also have edited the contents of this article.