Occurrence of PCDD/Fs and PCBs in Edible Land Snails (Helix pomatia) from Poland: Tissue Distribution and Implications for Food Safety

Abstract

Terrestrial snails are recognised as bioindicators of environmental contamination and may represent a source of dietary exposure to persistent organic pollutants (POPs). However, data on polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/Fs), and polychlorinated biphenyls (PCBs) in edible land snails remain limited. This study investigated PCDD/Fs, dioxin-like PCBs (dl-PCBs), and non-dioxin-like PCBs (ndl-PCBs) in the foot muscle and hepatopancreas of free-living Helix pomatia (H. pomatia) collected from two regions of Poland. A total of 48 snails (24 per region) were analysed as three pooled replicates per tissue type in each region. Thirty-five congeners were determined using high-resolution gas chromatography coupled with high-resolution mass spectrometry (HRGC-HRMS). Overall, only trace concentrations of selected PCDFs and dl-PCBs were detected, exclusively in hepatopancreas samples. Among PCDFs, only 2,3,7,8-TCDF and 1,2,3,7,8-PeCDF were quantified, whereas PCB 77 was the only quantified dl-PCB congener. All analysed PCDD congeners and ndl-PCBs were below the limit of quantification. TEQ values calculated using 2005 WHO-TEFs remained very low in all analysed samples, including under the upper-bound approach. The preferential detection of contaminants in the hepatopancreas was consistent with the higher lipid content of this tissue. The results indicate very low contamination of H. pomatia with dioxins and PCBs and low toxicological relevance under the investigated conditions.