Nontarget and Target Screening of Organohalogen Compounds in Mussels and Sediment from Hiroshima Bay, Japan: Occurrence of Novel Bioaccumulative Substances

摘要

Recent screening surveys have shown the presence of unknown halogenated compounds in the marine environment at , comparable levels to persistent organic pollutants (POPs). However, their exposure levels and profiles in marine organisms and bioaccumulative potentials remain unclear. The present study performed nontarget/target screening of organohalogen compounds (OHCs) in mussel and sediment samples collected from Hiroshima Bay, Japan, in 2012 and 2018 by using integrated analyses of two-dimensional gas chromatography- high resolution time-of-flight mass spectrometry (GC×GC-HRToFMS) and magnetic sector GC-HRMS. Nontarget analysis by GC×GC-HRToFMS revealed the detection of approximately 60 OHCs including unknown mixed halogenated compounds (UHC-Br_(3-5)Cl) with molecular formulae of C_9H_6Br_3ClO, C_9H_5Br_4ClO, and C_9H_4Br_5ClO in the mussel. Interestingly, UHC-Br_(3-5)Cl concentrations in the mussel samples, which were semi-quantified by GC-HRMS, were comparable to or higher than those of POPs at all the locations surveyed, and their geographical distribution patterns differed from those of other OHCs. These results suggest that UHC-Br_(3-5)Cl are ubiquitous in coastal waters of Hiroshima Bay and derived from a specific source(s). The biota-sediment accumulation factors (BSAFs) of UHC-Br_(3-5)Cl, estimated for a paired sample set of mussel (ng/g lw) and sediment (ng/g TOC), were 1 order of magnitude higher than those for POPs with similar log K_(OW) values, indicating their high bioaccumulative potential.