Polychlorinated dibenzo-p-dioxins, dibenzofurans and dioxin-like polychlorinated biphenyls in bivalve molluscs. Risk to Polish consumers?

Concentrations of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) were investigated in six species of bivalve mollusc purchased on the Polish retail market. The risk to consumers was calculated as a percentage of the tolerable weekly intake (TWI) (2 pg World Health Organization toxic equivalent (WHO-TEQ) kg^-1 body weight (b.w.)).

Altogether 32 samples were analysed using an isotope dilution technique with high resolution gas chromatography coupled with high resolution mass spectrometry.

Low levels of all analysed compounds were found. The range of PCDD/Fs was 0.08-0.37 pg WHO-TEQ g^-1 of wet weight (w.w.) and 0.04-0.41 pg WHO-TEQ g^-1 w.w. for DL-PCBs. The highest concentrations of all analysed compounds were found in Pacific oysters, at 0.30 pg WHO-TEQ g^-1 w.w. for the sum of PCDD/Fs and 0.19 pg WHO-TEQ g^-1 for the sum of DL-PCBs. These concentrations were 2-4 times higher than those detected in the other analysed mollusc species. Different species-dependent congener profiles were observed for PCDD/F concentrations, while PCB congener concentration profiles were species independent. The risk to consumers was assessed relating theoretical intakes of PCDD/Fs and DL-PCBs per 25, 50 and 100 g of consumption of molluscs per week to the TWI.

Taking into account the low consumption of molluscs in Poland and low concentrations of analysed compounds, neither adults nor children are likely to exceed the TWI by ingestion of food in this category.