Declining concentrations of persistent PCBs, PBDEs, PCDEs, and PCNs in harbor seals (Phoca vitulina) from the Salish Sea
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Article history:Available online 1 June 2013
(PCDDs or dioxins) and polychlorinated dibenzofurans (PCDFs orfurans) (Bright et al., 1999; Hagen et al., 1997). Industrial activitieshave contaminated a number of sites, and contributed to heavypolychlorinated biphenyl (PCB) contamination in Puget Sound,
e and toxic. KillerOcean have beenstent Organet al., 200
et al., 2000a). While the salmon-eating resident killer whathought to reect in part a global POP signal (Cullon2009), harbor seals (Phoca vitulina) provide an indication of morelocalized food web contamination in the Salish Sea. Harbor sealsare relatively abundant, widely distributed, and have a limitedhome range (50 km2) (Cottrell, 1996; Olesiuk, 2009). Previouswork ascribed dioxins and furans in harbor seals to pulp and paperprocesses in the Strait of Georgia, PCBs to a history of industrial in-puts into Puget Sound, and a global contribution in seals from re-mote locations (Ross et al., 2004).
Corresponding author. Tel.: +1 250 363 6806; fax: +1 250 363 6807.E-mail addresses: email@example.com (P.S. Ross), firstname.lastname@example.org
(M. Nol), Dyanna.Lambourn@dfw.wa.gov (D. Lambourn), email@example.com (N. Dangereld), firstname.lastname@example.org (J. Calambokidis),
Progress in Oceanography 115 (2013) 160170
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elsSteven.Jeffries@dfw.wa.gov (S. Jeffries).agricultural activities, municipal waste water and urban runoff,petrochemical facilities, and a variety of other industrial activities(Waldichuk, 1983). Pulp and paper mills have, in the past, releasedlarge quantities of by-produced polychlorinated dibenzo-p-dioxins
icals considered to be persistent, bioaccumulativwhales (Orcinus orca) of the Northeast Pacicfound to be particularly contaminated with Persilutants (POPs), especially the legacy PCBs (Krahn0079-6611/$ - see front matter 2013 Elsevier Ltd. All rights reserved.http://dx.doi.org/10.1016/j.pocean.2013.05.027ic Pol-7; Rossles areet al.,1. Introduction
While boasting a rich diversity of aquatic species, the Salish Sea,comprising the Strait of Georgia, Juan de Fuca Strait and PugetSound on the Pacic coast of North America, has been at the receiv-ing end of household, agricultural and industrial contaminantsfrom both within and outside its watershed boundaries. Sourceswithin the watershed include major wood and paper industries,
Washington, USA (West et al., 2008). In addition to local contami-nant inputs, global contaminants are delivered to the Salish Seathrough atmospheric transport (Nol et al., 2009) and biologicaldelivery to coastal food webs by migratory species, including sev-eral species of salmon (Christensen et al., 2005; Krummel et al.,2005).
Situated atop coastal food webs, many marine mammals canprovide an integrated signal of food web contamination by chem-As high trophic level, non-migratory marine mammals, harbor seals (Phoca vitulina) inhabiting the Straitof Georgia, Juan de Fuca Strait and Puget Sound (collectively referred to as the Salish Sea) in northwesternNorth America provide an integrated measure of coastal food web contamination. We measured conge-ner-specic polychlorinated biphenyls (PCBs), polybrominated diphenylethers (PBDEs), polychlorinateddiphenylethers (PCDEs) and polychlorinated naphthalenes (PCNs) in blubber biopsies from free-rangingharbor seal pups inhabiting four sites in the Salish Sea in 2003. While legacy PCBs dominated the com-position of these contaminants in seals at all sites (PCBs > PBDEs > PCDEs > PCNs), PBDEs were notewor-thy in that they averaged as much as 59% of total PCB concentrations. We further evaluated temporaltrends in seals sampled at one of these sites (Puget Sound) for PCBs and PBDEs between 1984 and2009, and for PCDEs and PCNs between 1984 and 2003. PBDE concentrations doubled every 3.1 yearsbetween 1984 and 2003, but appeared to decline thereafter. Over the course of the 20 years between1984 and 2003, PCB concentrations had declined by 81%, PCDEs declined by 71%, and PCNs by 98%. Over-all, results suggest that regulations and source controls have noticeably reduced inputs of these contam-inants to the Salish Sea, consequently reducing the associated health risks to marine wildlife. Weestimate the total mass of these contaminants in the 53,000 harbor seals of the Salish Sea in 2009 tobe 2.6 kg PCBs and 1.0 kg PBDEs, compared to just trace amounts of the PCDEs and PCNs.
2013 Elsevier Ltd. All rights reserved.a r t i c l e i n f o a b s t r a c tDeclining concentrations of persistent PCin harbor seals (Phoca vitulina) from the
Peter S. Ross a,, Marie Nol a,b, Dyanna Lambourn c, Na Institute of Ocean Sciences, Fisheries & Oceans Canada, P.O. Box 6000, 9860 West SaanbUniversity of Victoria, P.O. Box 3055, Victoria, British Columbia, Canada V8W 3P6cWashington Department of Fish and Wildlife, 7801 Phillips Road SW, Lakewood, WA 9dCascadia Research, 218 West 4th, Olympia, WA 98501, USA
journal homepage: www.s, PBDEs, PCDEs, and PCNslish Sea
l Dangereld a, John Calambokidis d, Steven Jeffries c
Road, Sidney, British Columbia, Canada V8L 4B2
evier .com/locate /pocean
The response of environmental compartments within the SalishSea to chemical regulations or source controls have been character-ized for a number of POPs, such as PCBs and polybrominated di-phenyl ethers (PBDEs) using sediment cores (Johannessen et al.,2008), dioxins and furans in Dungeness crab,Metacarcinus magister(Hagen et al., 1997), and PCBs and organochlorine pesticides in theeggs of double-crested cormorants, Phalacrocorax auritus (Harriset al., 2005). Despite such improvements, the regions killer whaleshave some of the highest PCB levels reported among the worldsmarine mammals, presenting troubling questions about the con-servation implications for POPs in marine food webs (Ross, 2006).
PCBs have represented a major toxicological concern for manyhigh trophic level species; they were banned in 1976 and 1977in the USA and Canada, respectively. PCBs have been associatedwith reproductive impairment, tumors, immunotoxicity and endo-crine disruption in captive and free-ranging marine mammals (DeSwart et al., 1994; Mos et al., 2006; Reijnders, 1986; Ross et al.,1996; Ylitalo et al., 2005). PBDEs have been widely used as ameretardants in electronics, furniture and other products; two ofthe three commercial formulations (penta- and octa-) were with-drawn from the market in 2004, while the third product is facinga North American phase-out in 2013. Less is known about the tox-icity of PBDEs to marine mammals, but similarities in structureswould suggest similar toxic effects. Studies demonstrate thatPBDEs affect the function of white blood cells in harbor seals (Frou-in et al., 2010). Polychlorinated diphenyl ethers (PCDEs) have beenattributed to impurities in pentachlorophenol (PCP) used as awood preservative in the lumber industry, as well as in a varietyof pesticides and other products (Becker et al., 1991). Polychlori-
Approximately 53,000 harbor seals are distributed over the17,000 km2 of the Salish Sea, feeding on Pacic hake (Merlucciusproductus), Pacic herring (Clupea pallasi), Pacic tomcod (Microga-dus proximus) and a variety of other pelagic and bottomsh species(Cullon et al., 2005; Lance et al., 2012; Olesiuk, 1993). They there-fore provide an integrated contaminant signal from the numeroussh and invertebrate prey species upon which they rely, and pro-vide insight into contamination hotspots and emerging contami-nants of concern (Cullon et al., 2005).
In this study, we evaluated spatial variation in PCB, PBDE, PCDEand PCN concentrations and patterns in harbor seals inhabitingsites throughout the transboundary waters of the Salish Sea. Inaddition, we evaluated temporal trends in the concentrations ofPCBs and PBDEs in harbor seals from southern Puget Sound duringthe period 19842009, and for PCDEs and PCNs for the period19842003.
2. Material and methods
2.1. Live-capture and sampling of seals for spatial assessment
We collected blubber biopsies from live-captured harbor sealpups from two locations in British Columbia, Canada (Hornby Is-land and the Fraser River estuary in Vancouver), and two locationsin Washington State, USA (Smith Island and Gertrude Island)(Fig. 1). Harbor seals were captured using one of two techniques.At the rocky Hornby Island site, individual seals were capturedby hand and using a sh landing net following a rapid yet careful
P.S. Ross et al. / Progress in Oceanography 115 (2013) 160170 161nated naphthalenes (PCNs) were intentionally produced as ameretardants and wood preservatives, but have also been describedas impurities in PCBs and as by-products of combustion ofchlorine-containing products (Falandysz, 1998; Yamashita et al.,2000).Fig. 1. Harbor seals were live-captured at four sites in 2003, including Hornby Island andStrait, Washington State, USA) and Gertrude Island (Puget Sound, Washington State, USAtemporal trend analyses.approach by a 3.5 m aluminum outboard boat (Cottrell et al.,2002). At the three remaining sites, which consisted of sandyhaul-out areas, multiple seals were captured at one time using arapidly deployed beach seine net (Jeffries et al., 1993). In all cases,body weight, body length, girth, and sex were determined for eachVancouver (Strait of Georgia, British Columbia, Canada), Smith Island (Juan de Fuca). Harbor seals were sampled during the period 19842009 from Gertrude Island for
2009 (n = 7). Samples from 1993, 1997 and 2009 were obtained
conditions, and quality assurance/quality control criteria used for
eanoPCBs by the Laboratory of Expertise for Aquatic Chemical Analysis(LEACA, Fisheries and Oceans Canada, Sidney BC) are describedelsewhere (Ikonomou et al., 2001; Ross et al., 2000a). The samplebatch for PCBs included a procedural blank, a replicate, and eithera certied reference material (CRM; herring) or a standard refer-ence material (SRM; harbor seal) sample (Ikonomou et al., 2001).Reference material data met established laboratory criteria of lessthan two standard deviations before batch data was deemedacceptable.
PBDEs, PCDEs, and PCNs were analyzed by AXYS Analytical Ser-vices, Ltd. (Sidney, BC, Canada) according to their laboratory proce-dures and criteria. The PBDE method is based on the U.S.Environmental Protection Agency (EPA) draft analytical methodsand procedures no. 1614 (USEPA Ofce of Science and Technology,2003). The PCDE and PCN analyses were carried out using an in-house GC/HRMS method with isotope dilution or internal standardquantication. The sample batch for PBDEs, PCDEs and PCNs in-by biopsy from live-captured seal pups, while samples from 1984and 1990 were obtained from freshly deceased seal pups whichwere found stranded (i.e. no decomposition and deemed to beotherwise in good condition based on blubber thickness measure-ments; results not shown). Individual seal samples were analyzedfor PCBs for all sampling years, for PBDEs for years 2003 and 2009,and for PCDEs and PCNs for 2003. For other years, individual sam-ples were pooled prior to analysis. PCDEs and PCNs were not deter-mined in 2009 samples owing to their extremely lowconcentrations in 2003.
2.3. Determination of PCB, PBDE, PCDE and PCN concentrations
Harbor seal blubber samples were analyzed for congener-spe-cic (peaks including co-eluting) PCBs (n = 183), PBDEs (n = 40),PCDEs (n = 45), and PCNs (n = 50) using high-resolution gas chro-matography/high-resolution mass spectrometry (HRGC/HRMS).
Extraction and clean-up procedures, instrumental analysis andseal captured, while age was estimated on the basis of tooth erup-tion, pelage, alertness, umbilicus state and general condition.
Blubber samples were collected using an Acu-Punch 6 mm(diameter) biopsy sampler (Acuderm, Ft Lauderdale, FL, USA) fol-lowing site cleansing and application of a local anesthetic as de-scribed elsewhere (Simms et al., 2000). Samples were wrapped inhexane-rinsed aluminum foil, placed in cryovials, and stored at20 C (eld) and later at 80 C (laboratory) until analysis. Allprocedures were carried out under the auspices of the respectiveanimal care committees and scientic research permits forresearchers in British Columbia (Fisheries and Oceans Canada Ani-mal Care Committee, using guidelines from the Canadian Councilon Animal Care; Scientic Research Permit) and Washington State(United States Marine Mammal Protection Act Research PermitsNos. 835, 782-1812 and 13430). In all circumstances, capturestress and holding time was minimized, and seals were releasedfollowing sampling 2090 min after capture.
2.2. Harbor seals for temporal trend measurements
In addition to the study on spatial contaminant trends in 2003,we obtained blubber samples from harbor seals to provide an over-view of temporal trends for PCBs, PBDEs, PCDEs and PCNs from onesite (Gertrude Island, Puget Sound). This included samples from1984 (n = 10), 1990 (n = 10), 1993 (n = 11), 1997 (n = 10), and
162 P.S. Ross et al. / Progress in Occluded a procedural blank and standard reference material(SRM), wherein batch data were deemed acceptable when theSRM results were within a percentage recovery of 80 and 120.Briey, samples for PBDEs, PCDEs, and PCNs were spiked with13C-labeled surrogate standards and then ground with anhydroussodium sulfate. Samples were transferred to a soxhlet thimble, sur-rogate standard was added, and samples were reuxed for 16 hwith dichloromethane (DCM). The extract was eluted through agel permeation column with 1:1 DCM:hexane. The extract was ap-plied to a partially deactivated Fluorisil column and eluted withhexane followed by 15:85 DCM:hexane. Eluates were then com-bined and eluted with 1:1 DCM:hexane and each fraction concen-trated. Samples were analyzed using an Ultima HRMS (MicromassInc., Manchester, UK) equipped with a Hewlett Packard 5890 GC(Agilent Technologies, Wilmington, USA) and a DB-5 Durabondcapillary column (60 m 0.25 mm, 0.10 lm lm). Percent lipid insamples was determined using the gravimetric lipid determinationby weight of extract method with dichloromethane.
Mono- and di-BDE data were not used for interpretation assurrogate recoveries were less than 10%. Since the isotope dilu-tion method of quantication produces data that are recoverycorrected, the slight variances from the method acceptance cri-teria are deemed not to affect the quantication of these ana-lytes. Included with each batch of samples was a proceduralblank.
Many congeners were not detectable in samples of harbor sealblubber. Total concentrations for PCBs, PBDEs, PCDEs and PCNsare calculated as the sum of the concentrations of the peaks thatwere detectable in at least 70% of the seal samples from all sites.Where congeners were undetectable, the detection limit wassubstituted. Congeners that were detected in less than 70% of thesamples were not included in calculations. All results are expressedon a lipid weight (lw) basis.
2.4. Mass balance calculation