title: Trophic dilution of cyclic volatile methylsiloxanes (cVMS) in the pelagic marine food web of Tokyo Bay, Japan.
abstract: Bioaccumulation and trophic transfer of cyclic volatile methylsiloxanes (cVMS), specifically octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), and dodecamethylcyclohexasiloxane (D6), were evaluated in the pelagic marine food web of Tokyo Bay, Japan. Polychlorinated biphenyl (PCB) congeners that are "legacy" chemicals known to bioaccumulate in aquatic organisms and biomagnify across aquatic food webs were used as a benchmark chemical (CB-180) to calibrate the sampled food web and as a reference chemical (CB-153) to validate the results. Trophic magnification factors (TMFs) were calculated from slopes of ordinary least-squares (OLS) regression models and slopes of bootstrap regression models, which were used as robust alternatives to the OLS models. Various regression models were developed that incorporated benchmarking to control bias associated with experimental design, food web dynamics, and trophic level structure. There was no evidence from any of the regression models to suggest biomagnification of cVMS in Tokyo Bay. Rather, the regression models indicated that trophic dilution of cVMS, not trophic magnification, occurred across the sampled food web. Comparison of results for Tokyo Bay to results from other studies indicated that bioaccumulation of cVMS was not related to type of food web (pelagic vs demersal), environment (marine vs freshwater), species composition, or location. Rather, results suggested that differences between study areas was likely related to food web dynamics and variable conditions of exposure resulting from non-uniform patterns of organism movement across spatial concentration gradients.
authors.affiliation: Dow Corning Corporation, Auburn, MI, USA. Electronic address: david.powell@dowcorning.com.
authors.forename: David E
authors.initials: DE
authors.lastname: Powell
authors.affiliation: Dow Corning Toray Co., Ltd., Chiba, Japan.
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Suganuma
authors.affiliation: Momentive Performance Materials Japan LLC, Gunma, Japan.
authors.forename: Keiji
authors.initials: K
authors.lastname: Kobayashi
authors.affiliation: Shin-Etsu Chemical Co., Ltd., Tokyo, Japan.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Nakamura
authors.affiliation: Wacker Asahikasei Silicone Co., Ltd., Tokyo, Japan.
authors.forename: Kouzo
authors.initials: K
authors.lastname: Ninomiya
authors.affiliation: JNC Corporation, Tokyo, Japan.
authors.forename: Kozaburo
authors.initials: K
authors.lastname: Matsumura
authors.affiliation: Shin-Etsu Chemical Co., Ltd., Tokyo, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Omura
authors.affiliation: Environmental Control Center Co., Ltd., Tokyo, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ushioka
mesh_terms: D000818:Animals; D061006:Bays; D004129:Dimethylpolysiloxanes / Q000032:analysis*; D004784:Environmental Monitoring; D020387:Food Chain; D014041:Tokyo; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D004129:Dimethylpolysiloxanes; D014874:Water Pollutants, Chemical
keywords: Benchmarking; Bioaccumulation; Bootstrap regression; Cyclic volatile methylsiloxanes (cVMS); Tokyo Bay, Japan; Trophic magnification