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 1980's.[1]


Content of the study

This paper 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 caused by 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. On a lipid weight basis (meaning the concentration of contaminants in the lipids) however no trend was observed. The reduced PBC concentration on a wet weight basis was caused by a reduced lipid content in the shrimp in recent years. The study therefore concluded that the PCBs concentrations in the Belgian sea didn't improve significantly in the 10 year period. The composition of the PCBs however did change during the monitoring period. The amount 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 when the PCB content doesn't change. The latter is therefore an indication the ban on the use and production of PCBs is effective.

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

References