Impact of salinity on PAH and halogenated PAH contamination and risks during the pickling of Chinese pickles

In this study, solid-phase extraction coupled with gas chromatography–triple quadrupole mass spectrometry was used for analyzing PAHs and XPAHs in pickles. The concentrations were 43.0±3.9 μg/kg for PAH24 (including EPA PAH 16 and EU PAH15+1) and 0.52±0.07 μg/kg for XPAH18 (including 11 chlorinated PAHs and 7 brominated PAHs) in commercially available xuecai, and 28.3±8.7 μg/kg for PAH24 and 0.25±0.11 μg/kg for XPAH18 in laboratory-pickled radish. Throughout the pickling process, concentrations of PAHs generally decreased, while XPAHs in xuecai and chlorinated PAHs (ClPAHs) in radish initially increased before declining. The elevated ClPAH levels in fermented radish compared to their unfermented counterparts, along with the newly formed 1-chlorinated pyrene in xuecai, highlighted the generation of ClPAHs during pickling. At lower salinity levels, the greater reduction in concentrations of PAHs corresponds with the largest increase in ClPAHs, suggesting potential chlorination of some PAHs into ClPAHs via microbial activity. Although concentrations of ClPAHs rose after pickling, the toxic equivalent quotients of PAH42 (including PAH24 and XPAH18) in pickles after fermentation were lower than those in both unfermented and fermenting samples, indicating that mature pickles did not increase the overall toxicity risk associated with PAHs and XPAHs.