Bioaccumulation and trophic transfer of cyclic volatile methylsiloxanes (cVMS) in the aquatic marine food webs of the Oslofjord, Norway

David E Powell,Merete Schøyen,Sigurd Øxnevad,Reinhard Gerhards,Thomas Böhmer,Martin Koerner,Jeremy Durham,Darren W Huff

doi:10.1016/j.scitotenv.2017.11.237

David E Powell, Merete Schøyen + Show 6 more

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https://doi.org/10.1016/j.scitotenv.2017.11.237

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Abstract

The trophic transfer of cyclic methylsiloxanes (cVMS) in aquatic ecosystems is an important criterion for assessing bioaccumulation and ecological risk. Bioaccumulation and trophic transfer of cVMS, specifically octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), and dodecamethylcyclohexasiloxane (D6), were evaluated for the marine food webs of the Inner and Outer Oslofjord, Norway. The sampled food webs included zooplankton, benthic macroinvertebrates, shellfish, and finfish species. Zooplankton, benthic macroinvertebrates, and shellfish occupied the lowest trophic levels (TL ≈2 to 3); northern shrimp (Pandalus borealis) and Atlantic herring (Clupea harengus) occupied the middle trophic levels (TL ≈3 to 4), and Atlantic cod (Gadus morhua) occupied the highest tropic level (TL>4.0). Trophic dynamics in the Oslofjord were best described as a compressed food web defined by demersal and pelagic components that were confounded by a diversity in prey organisms and feeding relationships. Lipid-normalized concentrations of D4, D5, and D6 were greatest in the lowest trophic levels and significantly decreased up the food web, with the lowest concentrations being observed in the highest trophic level species. Trophic magnification factors (TMF) for D4, D5, and D6 were <1.0 (range 0.3 to 0.9) and were consistent between the Inner and Outer Oslofjord, indicating that exposure did not impact TMF across the marine food web. There was no evidence to suggest biomagnification of cVMS in the Oslofjord. Rather, results indicated that trophic dilution of cVMS, not trophic magnification, occurred across the sampled food webs.

Highlights

Marine ecosystems such as the Oslofjord typically have very complex food webs that are defined by multiple, interconnected food chains that are confounded by a great diversity in prey organisms and feeding relationships
It was not possible to benchmark or authenticate δ15N across the food web (Δ15N) for the sampled food webs because samples collected from Oslofjord in 2008 were not analyzed for a reference material (e.g. PCB)
Results reported here are in agreement with the previoulsy reported work and provide further support that trophic dilution of Cyclic volatile methylsiloxanes (cVMS), not trophic magnification, occurred across the sampled food webs in the Oslofjord

Summary

Introduction

Cyclic volatile methylsiloxanes (cVMS) are a class of silicone compounds having an unusual combination of physical-chemical properties These materials are widely used in industrial and consumer applications worldwide, including use as key intermediates for the manufacture of siloxane polymers (Allen et al, 1997; Hobson et al, 1997), in dry cleaning solvents and industrial cleaning fluids (Horii and Kannan, 2008; Wang et al, 2013), and in a variety of personal care products such as shampoos and hair-conditioners, skin creams, cosmetics, and deodorants (Montemayor et al, 2013).

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