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

Abstract
Recent screening survey has 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 non-target/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 chromatograph–high resolution time-of-flight mass spectrometer (GC×GC–HRToFMS) and magnetic sector GC–HRMS. Non-target analysis by GC×GC–HRToFMS revealed the detection of approximately 60 OHCs including unknown mixed halogenated compounds (UHC-Br3–5Cl) with molecular formulae of C9H6Br3ClO, C9H5Br4ClO, and C9H4Br5ClO in the mussel. Interestingly, UHC-Br3–5Cl 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 pattern differed from those of other OHCs. These results suggest that UHC-Br3–5Cl are ubiquitous in coastal waters of Hiroshima Bay and are derived from a specific source(s). The biota-sediment accumulation factors (BSAFs) of UHC-Br3–5Cl, estimated for a paired sample set of mussel (ng/g lw) and sediment (ng/g TOC), were one order of magnitude higher than those for POPs with similar Log Kow values, indicating their high bioaccumuative potential.
Funding Information
  • Ministry of Education, Culture, Sports, Science and Technology
  • Japan Society for the Promotion of Science (18H06497, 19H01167, 19K21559, 19K22911)
  • Nippon Life Insurance Foundation

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