Cyclic volatile methylsiloxanes in fish from the Baltic Sea Amelie Kierkegaard a,⇑ , Anders Bignert b , Michael S. McLachlan a a Department of Applied Environmental Science (ITM), Stockholm University, SE-106 91 Stockholm, Sweden b Department of Contaminant Research, Swedish Museum of Natural History, SE-104 05 Stockholm, Sweden article info Article history: Available online 21 November 2012 Keywords: cVMS D5 Herring Seal abstract Laboratory studies suggest that the cyclic volatile methylsiloxanes (cVMS) octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6) will persist in the aquatic environment and bioaccumulate in fish. Here these cVMS were measured in herring collected in the Swedish waters of the Baltic Sea and the North Sea and in grey seals from the Baltic Proper. D4, D5, and D6 were present in herring muscle at concentrations around 10, 200, and 40 ng g 1 lipid weight, respectively. The ratio of these concentrations was similar to the relative magnitude of estimated emis- sions to water, suggesting that the efficiency of overall transfer through the environment and food web was similar (within a factor 2–3) for the three chemicals. The concentrations of D5 and D6 were similar in herring caught in the highly populated Baltic Proper and in the less populated Bothnian Sea and Bothnian Bay. The D4 concentrations were lower at the most remote northern station, suggesting that D4 is less persistent than D5 and D6. Herring from the North Sea had lower levels of all three chemicals. The con- centrations of D4, D5 and D6 in grey seal blubber were lower than the lipid normalized concentrations in herring, indicating that they do not biomagnify in grey seals. Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction Three cyclic volatile methylsiloxanes (cVMS), namely octa- methylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6), have been identi- fied as priority chemicals for environmental risk assessment (How- ard and Muir, 2010). They are high production volume chemicals used in the production of silicone polymers and as solvents or fra- grance carriers in personal care products, household products, and cleaning agents (Horii and Kannan, 2008; Brooke et al., 2009a,b,c). Use of these products results in emissions to wastewa- ter, and despite effective removal in sewage treatment plants a small fraction of the cVMS is present in the plant effluent (Dewil et al., 2006). Risk assessments prepared by the United Kingdom indicate that the major environmental exposure pathway of con- cern for these chemicals begins with discharge of sewage treatment plant effluent to recipient waters. There it is expected that the very hydrophobic properties of the cVMS (log K OW of 6.49, 8.03, and 9.06, respectively (Brooke et al., 2009a,b,c)) will result in them partition- ing to sediment, where they will persist, accumulate, and bioaccu- mulate in aquatic food webs. These chemicals are under consideration for regulation as very persistent, very bioaccumula- tive (vPvB) substances in the European Union (Brooke et al., 2009a,b,c). Field measurements demonstrating exposure of aquatic organ- isms to cVMS are scanty. All three cVMS have been detected in fish collected from the vicinity of wastewater discharges (Schlabach et al., 2007; Warner et al., 2010). Off Svalbard, D5 and D6 were also quantified in 1 of 5 and 2 of 5 fish, respectively, collected at a site remote from wastewater discharges (Warner et al., 2010). cVMS were also occasionally detected in biota samples analyzed in a screening study conducted in the Nordic countries. There the con- centrations ranged from <5–100 ng g 1 wet weight (ww), whereby detectable levels appeared to be associated with diffuse/urban sources (Kaj et al., 2005). To date there is little information avail- able on cVMS levels in biota distant from suspected sources. This information is needed to assess the potential for long range trans- port of cVMS in the aquatic environment and to establish the spa- tial implications of cVMS emissions. In this study we analyze cVMS concentrations in biota from the Baltic Sea. The Baltic is a marginal sea with a large population (85 million) within its watershed and a long water residence time (25 years), which makes it susceptible to anthropogenic contam- ination. We analyzed cVMS in herring that were collected from around the Baltic Sea and in grey seals sampled in the Baltic Proper. 0045-6535/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.chemosphere.2012.10.048 ⇑ Corresponding author. Tel.: +46 8 674 7182. E-mail address: amelie.kierkegaard@itm.su.se (A. Kierkegaard). Chemosphere 93 (2013) 774–778 Contents lists available at SciVerse ScienceDirect Chemosphere journal homepage: www.elsevier.com/locate/chemosphere