Last updated on 17 February 2006
Dioxins and dioxin-like PCBs in farmed and wild fish and shellfish
Food Survey Information Sheet 03/06
In order to allow a robust dietary intake of dioxins and PCBs from fish to be estimated, composite samples of 47 species of farmed and wild fish and shellfish consumed in the UK were analysed for dioxins and PCBs. Individual samples were also tested to establish concentration ranges in five species. Dioxins and PCBs were detected at low concentrations in all samples, with slightly higher concentrations generally being found in oily than in non-oily fish.
Where comparisons are possible, concentrations are generally lower than found in previous surveys. Only one individual sample from the 158 analysed exceeded the regulatory limit for dioxins in fish. Based on the results of this survey, the Agency�s advice on the consumption of oily fish remains unchanged.
Dioxins and PCBs were analysed in 47 composite samples made up from 30 or 60 individual samples of single species of fish and shellfish, and additionally in up to 30 individual samples each of mackerel, herring, wild and farmed salmon and farmed trout.
Dioxins and PCBs were found at low concentrations in all of the samples analysed. Total TEQ concentrations were in the range 0.02 - 9.5 ng WHO-TEQ/kg fresh weight, with the exception of one sample of mackerel that contained a level of 28 ng WHO-TEQ/kg fresh weight.
A new limit for the combination of dioxins plus dioxin-like PCBs and a new action level for dioxin-like PCBs in fish have been agreed since the samples were obtained. One herring contained a total TEQ concentration above the new limit for dioxins plus dioxin-like PCBs, while one herring, one mackerel and the composite sardines/pilchards samples contained concentrations of dioxin-like PCBs that were above the new EC action level.
There were no significant differences between the levels of dioxins in wild and farmed salmon, but the levels of dioxin-like PCBs, and therefore of total TEQs, were higher in the latter. Organic salmon and trout had similar dioxin and dioxin-like PCB concentrations to the conventionally farmed fish.
Where a comparison was possible, concentrations were generally found to have fallen since previous surveys.
Based on the results of this survey, the Agency�s advice on the consumption of oily fish remains unchanged. Consumers should eat at least two portions of fish per week, one of which should be oily. Girls and women who may have a baby one day are advised to limit their consumption of oily fish to two portions per week while all other consumers are advised to limit their consumption of oily fish to four portions per week.
As some non-oily fish species contain higher levels of dioxins and PCBs than others, people who eat a lot of fish should vary the species of fish they eat.