Toxin Studies
Food Web Bioaccumulation Model for Resident Killer Whales from the Northeastern Pacific Ocean as a Tool for the Derivation of PBDE-Sediment Quality Guidelines. Alava, Juan José, et al. (2015)
Persistent organic pollutants in chinook salmon (Oncorhynchus tshawytschea): implications for resident killer whales of British Columbia and adjacent waters. Cullon, Donna L., et al. (2009)
Going viral: Concerns rise over potential impacts of disease on the ecosystem. Dunagan, C. (2015).
Vulnerability of a killer whale social network to disease outbreaks. Guimaraes, P.R., et al. (2007).
Killer Whales (Orcinus orca) Face Protracted Health Risks Associated with Lifetime Exposure to PCBs. Hickie, Brendan E., et al. (2007).
Effects of age, sex and reproductive status on persistent organic pollutant concentrations in "Southern Resident" killer whales. Krahn M, et al. (2009).
Persistent organic pollutants and stable isotopes in biopsy samples (2004/2006) from Southern Resident killer whales. Krahn M, et al. (2007).
Modulation in Persistent Organic Pollutant Concentration and Profile by Prey Availability and Reproductive Status in Southern Resident Killer Whale Scat Samples. Lundin J, et al. (2016).
Persistent Organic Pollutant Determination in Killer Whale Scat Samples: Optimization of a Gas Chromatography/Mass Spectrometry Method and Application to Field Samples. Lundin J, et al. (2015).
Risk factor determination and qualitative risk assessment of Mucormycosis in Harbor Porpoise, an emergent fungal disease in Salish Sea marine mammals. Norman, Stephanie A., et al. (2022).
Respiratory Microbiome of Endangered Southern Resident Killer Whales and Microbiota of Surrounding Sea Surface Microlayer in the Eastern North Pacific. Raverty, Stephen A., et al. (2017).
PBDEs, PBBs, and PCNs in Three Communities of Free-Ranging Killer Whales (Orcinus orca) from the Northeastern Pacific Ocean. Rayne, Sierra, et al. (2004).
Declining concentrations of persistent PCBs, PBDEs, PCDEs, and PCNs in harbor seals (Phoca vitulina) from the Salish Sea. Ross, Peter S., et al. (2013).
High PCB concentrations in free-ranging Pacific killer whales, Orcinus orca: Effects of age, sex and dietary preference. Ross, Peter S., et al. (2000).
Killer whales as sentinels of marine ecosystem contamination. Ross, Peter S. (2002).
Polybrominated Diphenyl Ethers in Marine Ecosystems of the American Continents: Foresight from Current Knowledge. Shaw, Susan D. and Kurunthachalam Kannan
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Alava, Juan José, Peter S. Ross & Frank A. P. C. Gobas (2015). Food Web Bioaccumulation Model for Resident Killer Whales from the Northeastern Pacific Ocean as a Tool for the Derivation of PBDE-Sediment Quality Guidelines. Arch Environ Contam Toxicol DOI 10.1007/s00244-015-0215-y.
ABSTRACT
Resident killer whale populations in the NE Pacific Ocean are at risk due to the accumulation of pollutants, including polybrominated diphenyl ethers (PBDEs). To assess the impact of PBDEs in water and sediments in killer whale Critical Habitat, we developed a food web bioaccumulation model. The model aims to estimate PBDE concentrations in killer whales based on PBDE concentrations in sediments and the water column throughout a lifetime of exposure. Calculated and observed PBDE concentrations exceeded the only toxicity reference value available for PBDEs in marine mammals (1500 µg/kg lipid) in southern resident killer whales but not in northern resident killer whales. Temporal trends (1993–2006) for PBDEs observed in southern resident killer whales showed a doubling time of ˜5 years. If current sediment quality guidelines available in Canada for PCBs are applied to PBDEs, it can be expected that PBDE concentrations in killer whales will exceed available toxicity reference values by a large margin. Model calculations suggest that a PBDE concentration in sediments of approximately 1.0 µg/kg dw produces PBDE concentrations in resident killer whales that are below the current toxicity reference value for 95% of the population, with this value serving as a precautionary benchmark for a management-based approach to reducing PBDE health risks to killer whales. The food web bioaccumulation model may be a useful risk management tool in support of regulatory protection for killer whales.
Full paper HERE.
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Cullon, Donna L., Mark B. Yunker, Carl Alleyne, Neil J. Dangerfield, Sandra O'Neill, Michael J. Whiticar and Peter Ross (2009). Persistent organic pollutants in chinook salmon (Oncorhynchus tshawytschea): implications for resident killer whales of British Columbia and adjacent waters. Environmental Toxicology and Chemistry, Vol. 28, No. 1, pp. 148-161, 2009.
ABSTRACT
We measured persistent organic pollutant (POP) concentrations in chinook salmon (Oncorhynchus tshawytscha) in order to characterize dietary exposure in the highly contaminated, almon-eating northeastern Pacific resident killer whales. We estimate that 97 to 99% of polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), dichlorodiphenyltrichloroethane (DDT), and hexachlorocyclohexane (HCH) in returning adult chinook were acquired during their time at sea. Highest POP concentrations (including PCBs, PCDDs, PCDFs, and DDT) and lowest lipids were observed in the more southerly chinook sampled. While feeding by salmon as they enter some more POP-contaminated near-shore environments inevitably contribute to their contamination, relationships observed between POP patterns and both lipid content and ∑13C also suggest a migration-related metabolism and loss of the less-chlorinated PCB congeners. This has implications for killer whales, with the more PCB-contaminated salmon stocks in the south partly explaining the 4.0 to 6.6 times higher estimated daily intake for ∑PCBs in southern resident killer whales compared to northern residents. We hypothesize that the lower lipid content of southerly chinook stocks may cause southern resident killer whales to increase their salmon consumption by as much as 50%, which would further increase their exposure to POPs.
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Dunagan, Chris. 2015. Going viral: Concerns rise over potential impacts of disease on the ecosystem. Encyclopedia of Puget Sound.
ABSTRACT
From orcas to starfish to humans, disease affects every living creature in the ecosystem. Scientists are increasingly alarmed by its potential to devastate already compromised populations of species in Puget Sound.
Full article HERE.
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Guimaraes, P.R. Jr., M.A. de Menezes, R.W. Baird, D. Lusseau, P. Guimaraes, and S.F. dos Reis. 2007. Vulnerability of a killer whale social network to disease outbreaks. Physical Review E 76, 042901.
ABSTRACT
Emerging infectious diseases are among the main threats to conservation of biological diversity. A crucial task facing epidemiologists is to predict the vulnerability of populations of endangered animals to disease outbreaks. In this context, the network structure of social interactions within animal populations may affect disease spreading. However, endangered animal populations are often small and to investigate the dynamics of small networks is a difficult task. Using network theory, we show that the social structure of an endangered population of mammal-eating killer whales is vulnerable to disease outbreaks. This feature was found to be a consequence of the combined effects of the topology and strength of social links among individuals. Our results uncover a serious challenge for conservation of the species and its ecosystem. In addition, this study shows that the network approach can be useful to study dynamical processes in very small networks.
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Hickie, Brendan E., Peter S. Ross, Robie W. Macdonald, and John K. B. Ford (2007). Killer Whales (Orcinus orca) Face Protracted Health Risks Associated with Lifetime Exposure to PCBs. Environ. Sci. Technol., 41 (18), 6613 -6619.
ABSTRACT
Polychlorinated biphenyl (PCB) concentrations declined rapidly in environmental compartments and most biota following implementation of regulations in the 1970s. However, the metabolic recalcitrance of PCBs may delay responses to such declines in large, long-lived species, such as the endangered and highly PCB-contaminated resident killer whales (Orcinus orca) of the Northeastern Pacific Ocean. To investigate the influence of life history on PCB-related health risks, we developed models to estimate PCB concentrations in killer whales during the period from 1930 forward to 2030, both within a lifetime (~50 years) and across generations, and then evaluated these in the context of health effects thresholds established for marine mammals. Modeled PCB concentrations in killer whales responded slowly to changes in loadings to the environment as evidenced by slower accumulation and lower magnitude increases in PCB concentrations relative to prey, and a delayed decline that was particularly evident in adult males. Since PCBs attained peak levels well above the effects threshold (17 mg/kg lipid) in ~1969, estimated concentrations in both the northern and the more contaminated southern resident populations have declined gradually. Projections suggest that the northern resident population could largely fall below the threshold concentration by 2030 while the endangered southern residents may not do so until at least 2063. Long-lived aquatic mammals are therefore not protected from PCBs by current dietary residue guidelines.
Full paper HERE.
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Krahn, Margaret M., M. Bradley Hanson, Gregory S. Schorr, Candice K. Emmons, Douglas G. Burrows, Jennie L. Bolton, Robin W. Baird, Gina M. Ylitalo (2009). Effects of age, sex and reproductive status on persistent organic pollutant concentrations in "Southern Resident" killer whales. Mar. Pollut. Bull. (2009), doi:10.1016/j.marpolbul.2009.05.014.
ABSTRACT
"Southern Resident" killer whales (Orcinus orca) that comprise three fish-eating "pods" (J, K and L) were listed as "endangered" in the US and Canada following a 20% population decline between 1996 and 2001. Blubber biopsy samples from Southern Resident juveniles had statistically higher concentrations of certain persistent organic pollutants than were found for adults. Most Southern Resident killer whales, including the four juveniles, exceeded the health-effects threshold for total PCBs in marine mammal blubber. Maternal transfer of contaminants to the juveniles during rapid development of their biological systems may put these young whales at greater risk than adults for adverse health effects (e.g., immune and endocrine system dysfunction). Pollutant ratios and field observations established that two of the pods (K- and L-pod) travel to California to forage. Nitrogen stable isotope values, supported by field observations, indicated possible changes in the diet of L-pod over the last decade.
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Krahn, Margaret M., M. Bradley Hanson, Robin W. Baird, Richard H. Boyer, Douglas G. Burrows, Candice K. Emmons, John K.B. Ford, Linda L. Jones, Dawn P. Noren, Peter S. Ross, Gregory S. Schorr, Tracy K. Collier (2007). Persistent organic pollutants and stable isotopes in biopsy samples (2004/2006) from Southern Resident killer whales. Marine Pollution Bulletin xxx (2007) xxx-xxx.
ABSTRACT
"Southern Resident" killer whales include three "pods" (J, K and L) that reside primarily in Puget Sound/Georgia Basin during the spring, summer and fall. This population was listed as "endangered" in the US and Canada following a 20% decline between 1996 and 2001. The current study, using blubber/epidermis biopsy samples, contributes contemporary information about potential factors (i.e., levels of pollutants or changes in diet) that could adversely affect Southern Residents. Carbon and nitrogen stable isotopes indicated J- and L-pod consumed prey from similar trophic levels in 2004/2006 and also showed no evidence for a large shift in the trophic level of prey consumed by L-pod between 1996 and 2004/2006. ΣPPCBs decreased for Southern Residents biopsied in 2004/2006 compared to 1993-1995. Surprisingly, however, a three-year-old male whale (J39) had the highest concentrations of ΣPPBDEs, ΣPHCHs and HCB. POP ratio differences between J- and L-pod suggested that they occupy different ranges in winter.
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Lundin, Jessica I., Gina M. Ylitalo, Rebecca K. Booth, Bernadita Anulacion, Jennifer A. Hempelmann, Kim M. Parsons, Deborah A. Giles, Elizabeth A. Seely, M. Bradley Hanson, Candice K. Emmons, and Samuel K. Wasser (2016) Modulation in Persistent Organic Pollutant Concentration and Profile by Prey Availability and Reproductive Status in Southern Resident Killer Whale Scat Samples Environ. Sci. Technol., Article ASAP DOI: 10.1021/acs.est.6b00825
ABSTRACT
Persistent organic pollutants (POPs), specifically PCBs, PBDEs, and DDTs, in the marine environment are well documented, however accumulation and mobilization patterns at the top of the food-web are poorly understood. This study broadens the understanding of POPs in the endangered Southern Resident killer whale population by addressing modulation by prey availability and reproductive status, along with endocrine disrupting effects. A total of 140 killer whale scat samples collected from 54 unique whales across a 4 year sampling period (2010–2013) were analyzed for concentrations of POPs. Toxicant measures were linked to pod, age, and birth order in genotyped individuals, prey abundance using open-source test fishery data, and pregnancy status based on hormone indices from the same sample. Toxicant concentrations were highest and had the greatest potential for toxicity when prey abundance was the lowest. In addition, these toxicants were likely from endogenous lipid stores. Bioaccumulation of POPs increased with age, with the exception of presumed nulliparous females. The exceptional pattern may be explained by females experiencing unobserved neonatal loss. Transfer of POPs through mobilization of endogenous lipid stores during lactation was highest for first-borns with diminished transfer to subsequent calves. Contrary to expectation, POP concentrations did not demonstrate an associated disruption of thyroid hormone, although this association may have been masked by impacts of prey abundance on thyroid hormone concentrations. The noninvasive method for measuring POP concentrations in killer whales through scat employed in this study may improve toxicant monitoring in the marine environment and promote conservation efforts.
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Lundin, Jessica I., Russell L. Dills, Gina M. Ylitalo, M. Bradley Hanson, Candice K. Emmons, Gregory S. Schorr, Jacqui Ahmad, Jennifer A. Hempelmann, Kim M. Parsons, Samuel K. Wasser (2015) Persistent Organic Pollutant Determination in Killer Whale Scat Samples: Optimization of a Gas Chromatography/Mass Spectrometry Method and Application to Field Samples Arch Environ Contam Toxicol DOI 10.1007/s00244-015-0218-8
ABSTRACT
Biologic sample collection in wild cetacean populations is challenging. Most information on toxicant levels is obtained from blubber biopsy samples; however, sample collection is invasive and strictly regulated under permit, thus limiting sample numbers. Methods are needed to monitor toxicant levels that increase temporal and repeat sampling of individuals for population health and recovery models. The objective of this study was to optimizemeasuring trace levels (parts per billion) of persistent organic pollutants (POPs), namely polychlorinated-biphenyls (PCBs), polybrominated-diphenyl-ethers (PBDEs), dichlorodiphenyltrichloroethanes (DDTs), and hexachlorocyclobenzene, in killer whale scat (fecal) samples. Archival scat samples, initially collected, lyophilized, and extracted with 70 % ethanol for hormone analyses, were used to analyze POP concentrations. The residual pellet was extracted and analyzed using gas chromatography coupled with mass spectrometry.
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Norman SA, Huggins JL, Lambourn DM, Rhodes LD, Garner MM, Bolton JL, Gaydos JK, Scott A, Raverty S and Calambokidis J (2022) Risk factor determination and qualitative risk assessment of Mucormycosis in Harbor Porpoise, an emergent fungal disease in Salish sea marine mammals. Front. Mar. Sci. 9:962857. doi: 10.3389/fmars.2022.962857
ABSTRACT
Mucorales infections are increasing in frequency and are a One Health pathogen of concern. In humans and domestic animals, risk factors include being immunocompromised, elevated circulating serum iron, contaminated open wounds, or metabolic diseases such as ketoacidosis or uncontrolled diabetes. Mucormycosis was first identified in 2012 in Pacific Northwest marine mammals, predominantly in harbor porpoises. We performed an assessment to determine the overall qualitative risk, or risk score, of mucormycosis in harbor porpoises. Risk factors for this disease are unknown in aquatic mammals. In a separate risk factor analysis, potential risk factors such as pollutants, trace metals (e.g., iron), and co-infection with other pathogens (e.g., viruses and Brucella spp.) were examined in mucormycosis cases and noncases using a matched case-control study design, to determine the presence and strength of association of these factors with mucormycosis. Disease severity (gross and histopathology) and exposure scores were multiplied together to obtain the overall risk scores of 9 -16 which corresponded to moderate and severe, respectively. In the risk factor analysis, the factors most strongly associated with a mucormycosis case, relative to a control, were elevated liver iron, decreased blubber thickness, and the decreased ratio of the sum of PCB congeners/sum of PBDE congeners. The results of this study suggest that mucormycosis may pose an inordinately high risk to harbor porpoises (and potentially sympatric species in the Salish Sea such as southern resident killer whales) based on the detected prevalence and the severity of lesions observed at necropsy. However, the risk may be greater on an individual basis compared to the overall population, and is likely related to other factors such as increased POP and heavy metal burdens.
Full paper HERE.
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Raverty, Stephen A., Linda D. Rhodes, Erin Zabek, Azad Eshghi, Caroline E. Cameron, M. Bradley Hanson & J. Pete Schroeder (2017) Respiratory Microbiome of Endangered Southern Resident Killer Whales and Microbiota of Surrounding Sea Surface Microlayer in the Eastern North Pacific. Scientific Reports 7, Article number: 394
ABSTRACT
In the Salish Sea, the endangered Southern Resident Killer Whale (SRKW) is a high trophic indicator of ecosystem health. Three major threats have been identified for this population: reduced prey availability, anthropogenic contaminants, and marine vessel disturbances. These perturbations can culminate in significant morbidity and mortality, usually associated with secondary infections that have a predilection to the respiratory system. To characterize the composition of the respiratory microbiota and identify recognized pathogens of SRKW, exhaled breath samples were collected between 2006–2009 and analyzed for bacteria, fungi and viruses using (1) culture-dependent, targeted PCR-based methodologies and (2) taxonomically broad, non-culture dependent PCR-based methodologies. Results were compared with sea surface microlayer (SML) samples to characterize the respective microbial constituents. An array of bacteria and fungi in breath and SML samples were identified, as well as microorganisms that exhibited resistance to multiple antimicrobial agents. The SML microbes and respiratory microbiota carry a pathogenic risk which we propose as an additional, fourth putative stressor (pathogens), which may adversely impact the endangered SRKW population.
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Rayne, Sierra, Michael G. Ikonomou, Peter S. Ross, Graeme M. Ellis, Lance G. Barrett-Lennard (2004) PBDEs, PBBs, and PCNs in Three Communities of Free-Ranging Killer Whales (Orcinus orca) from the Northeastern Pacific Ocean. American Chemical Society
ABSTRACT
Polybrominated diphenyl ethers (PBDEs), polybrominated biphenyls (PBBs), and polychlorinated naphthalenes (PCNs) were quantified in blubber biopsy samples collected from free-ranging male and female killer whales (Orcinus orca) belonging to three distinct communities (southern residents, northern residents, and transients) from the northeastern Pacific Ocean. High concentrations of PBDE were observed in male southern residents (942 ± 582 ng/g lw), male and female transients (1015 ± 605 and 885 ± 706 ng/g lw, respectively), and male and female northern residents (203 ± 116 and 415 ± 676 ng/g lw, respectively). Because of large variation within sample groups, PBDE levels generally did not differ statistically with the exception of male northern residents, which had lower PBDE concentrations than male southern residents, male transients, and female transients, perhaps reflecting the consumption of less contaminated prey items. Male transient killer whales, which consume high trophic level prey including other cetaceans and occasionally spend time near populated areas, had PBDE concentrations approximately equal to southern residents. No significant age-related relationships were observed for PBDE concentrations. PBDE concentrations were approximately 1-3 orders of magnitude greater than those of PBB (3.0-31 ng/g lw) and PCN (20-167 ng/g lw) measured in a subset of samples, suggesting that PBDEs may represent a contaminant class of concern in these marine mammals.
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Ross, Peter S., Marie Noël, Dyanna Lambourn, Neil Dangerfield, John Calambokidis, Steven Jeffries (2013) Declining concentrations of persistent PCBs, PBDEs, PCDEs, and PCNs in harbor seals (Phoca vitulina) from the Salish Sea. Progress in Oceanography, Volume 115, August 2013, Pages 160–170.
ABSTRACT
As high trophic level, non-migratory marine mammals, harbor seals (Phoca vitulina) inhabiting the Strait of Georgia, Juan de Fuca Strait and Puget Sound (collectively referred to as the Salish Sea) in northwestern North America provide an integrated measure of coastal food web contamination. We measured congener-specific polychlorinated biphenyls (PCBs), polybrominated diphenylethers (PBDEs), polychlorinated diphenylethers (PCDEs) and polychlorinated naphthalenes (PCNs) in blubber biopsies from free-ranging harbor seal pups inhabiting four sites in the Salish Sea in 2003. While legacy PCBs dominated the composition of these contaminants in seals at all sites (PCBs > PBDEs > PCDEs > PCNs), PBDEs were noteworthy in that they averaged as much as 59% of total PCB concentrations. We further evaluated temporal trends in seals sampled at one of these sites (Puget Sound) for PCBs and PBDEs between 1984 and 2009, and for PCDEs and PCNs between 1984 and 2003. PBDE concentrations doubled every 3.1 years between 1984 and 2003, but appeared to decline thereafter. Over the course of the 20 years between 1984 and 2003, PCB concentrations had declined by 81%, PCDEs declined by 71%, and PCNs by 98%. Overall, results suggest that regulations and source controls have noticeably reduced inputs of these contaminants to the Salish Sea, consequently reducing the associated health risks to marine wildlife. We estimate the total mass of these contaminants in the 53,000 harbor seals of the Salish Sea in 2009 to be 2.6 kg PCBs and 1.0 kg PBDEs, compared to just trace amounts of the PCDEs and PCNs.
Full paper HERE.
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Dr. Peter S. Ross, Fisheries and Oceans Canada (2002) Killer whales as sentinels of marine ecosystem contamination.
Marine Ecosystem Health Program (MEHP)
ABSTRACT
The southern resident killer whale (Orcinus orca) population depends on the availability of prey in the shared coastal waters of Washington state and the province of British Columbia during much of the year. Declining population numbers (down 20% since 1996) have raised concerns in both Canada and the United States, leading to a threatened listing in Canada in 1999 and a recent petition to list this population under the terms of U.S. Endangered Species Act (ESA). Reports have cited diminishing prey (salmon) abundance, heavy vessel traffic and high contaminant levels. Contaminants including PCBs have been associated with adverse health effects in both humans and wildlife, including endocrine disruption, immunotoxicity and reproductive impairment. Our recent report citing northeast Pacific killer whales as among the most contaminated in the world underscores the need to better understand the source of toxic chemicals and their fate in killer whales at the top of the coastal food chain. We have initiated a two-year MEHP project (Year One: 2001; Year Two, this proposal: 2002) to evaluate the levels and patterns of Persistent Organic Pollutants (POPs; approximately 250 chemicals, including the PCBs, dioxins and pesticides) in the primary dietary component of southern resident killer whales, Chinook salmon. In Year One, we initiated a graduate student research project, set up working relationships with several laboratories, conducted preliminary experiments on stable isotopes and fatty acids, collected Chinook smolts and adults from two stocks in Puget Sound, subsampled and prepared tissues for contaminant and other analyses. Contaminant analysis is currently underway. In Year Two, we plan to complete fatty acid and stable isotope analyses, interpret data from these and contaminant analysis in the context of Chinook life history and ecology, killer whale data and food chain structure. This work will help to assess the relative importance of local vs. offshore sources of contaminants. Results will be linked to contaminant data from i) concurrent studies of Strait of Georgia fish; ii) southern resident killer whales; and iii) Puget Sound harbor seals. Results will be further interpreted using multivariate statistical evaluation of contaminant patterns and a food chain bioaccumulation model. Results will also be related to our ongoing research into the effects of POPs on the health of killer whales. This project will help to bridge Canadian and U.S. approaches to assessing contaminant levels in shared waters. Results from this research will be provided to stakeholders by way of a dedicated website and a published fact sheet. In this manner, we plan to better understand the state of contamination of the marine ecosystem in Puget Sound, the Strait of Georgia and Juan de Fuca Strait, and the risk that this contamination presents to killer whales and other high trophic level consumers.
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Ross, Peter S.; G. M. Ellis; M. G. Ikonomou; L. G. Barrett-Lennard; and R. F. Addison (2000) High PCB concentrations in free-ranging Pacific killer whales, Orcinus orca: Effect of age, sex and dietary preference Marine Pollution Bulletin 40:504-515.
ABSTRACT
Blubber biopsy samples were obtained for contaminant analysis from two discrete populations of killer whales (Orcinus orca) which frequent the coastal waters of British Columbia, Canada. Detailed life history information for the fish-eating 'resident' population, comprising two distinct communities, and the marine mammal-eating 'transient' killer whale population, provided an invaluable reference for the interpretation of contaminant concentrations. Total PCB concentrations (sum of 136 congeners detected) were surprisingly high in all three communities, but transient killer whales were particularly contanimated. PCB concentrations increased with age in males, but were greatly reduced in reproductively active females. The absence of age, sex and inter-community differences in concentrations of polychlorinated- dibenzo-p-dioxins (PCDDs) and- dibenzofurans (PCDFs) may have partly reflected low dietary levels, but more importantly, metabolic removal of dioxin-like compounds in killer whales. While information on toxic thresholds does not exist for PCBs in cetaceans, total 2,3,7,8-TCDD Toxic Equivalent (TEQ) in most killer whales sampled easily surpassed adverse effects levels established for harbour seals, suggesting that the majority of free-ranging killer whales in this region are at risk for toxic effects. The southern resident and transient killer whales of British Columbia can now be considered among the most contaminated cetaceans in the world.
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Shaw, Susan D. and Kurunthachalam Kannan 2009. Polybrominated Diphenyl Ethers in Marine Ecosystems of the American Continents: Foresight from Current Knowledge. Reviews on Environmental Health 24 (2009) 157-229.
ABSTRACT
Polybrominated diphenyl ethers (PBDEs) are a class of synthetic halogenated organic compounds used in commercial and household products, such as textiles, furniture, and electronics, to increase their flame ignition resistance and to meet fire safety standards. The demonstrated persistence, bioaccumulation, and toxic potential of these compounds in animals and in humans are of increasing concern. The oceans are considered global sinks for PBDEs, as higher levels are found in marine organisms than in terrestrial biota. For the past three decades, North America has dominated the world market demand for PBDEs, consuming 95% of the penta-BDE formulation. Accordingly, the PBDE concentrations in marine biota and people from North America are the highest in the world and are increasing. Despite recent restrictions on penta- and octa-BDE commercial formulations, penta-BDE containing products will remain a reservoir for PBDE release for years to come, and the deca-BDE formulation is still in high-volume use. In this paper, we review all available data on the occurrence and trends of PBDEs in the marine ecosystems (air, water, sediments, invertebrates, fish, seabirds, and marine mammals) of North and South America. We outline here our concerns about the potential future impacts of large existing stores of banned PBDEs in consumer products, and the vast and growing reservoirs of deca-BDE as well as new and naturally occurring brominated compounds on marine ecosystems.
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