Occurrence of anthropogenic and naturally-produced organohalogenated compounds in tissues of Black Sea harbour porpoises

Harbour porpoises are one of the three cetacean species inhabiting the Black Sea. This is the first study to report on polybrominated diphenyl ethers (PBDEs) and naturally-produced compounds, methoxylated PBDEs (MeO-PBDEs) and polybrominated hexahydroxanthene derivatives (PBHDs), in tissues (kidney, brain, blubber, liver, muscle) of male harbour porpoises (11 adults, 9 juveniles) from the Black Sea. Lipid-normalized concentrations decreased from muscle > blubber > liver > kidney > brain for the sum of polychlorinated biphenyls (PCBs) and for the sum of PBDEs. Among the naturally-produced compounds, levels of PBHDs were higher than of MeO-PBDEs, with tri-BHD and 6-MeO-BDE 47 being the dominant compounds for both groups, respectively. Concentrations of naturally-produced compounds decreased from blubber to brain, similarly to the sum of DDT and metabolites (DDXs). Concentrations of DDXs were highest, followed by PCBs, HCB, PBHDs, PBDEs and MeO-PBDEs. Levels of PCBs and PBDEs in blubber were lower than concentrations reported for harbour porpoises from the North Sea, while concentrations of DDXs were higher

Use of Physiologically Based Pharmacokinetic (PBPK) Models in Marine Mammal Toxicology

peer reviewedPhysiologically based pharmacokinetic (PBPK) models are mathematical models that are largely based upon the physiological characteristics of the species and the biochemical properties of the chemical of interest. They quantitatively describe and predict the kinetics of pollutants inside the body and can be of major importance for risk assessment of chemicals in marine mammals. PBPK models which consist of five compartments (liver, blubber, kidney, brain, and the rest of the body) were made for selected polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in order to address the bioaccumulation of these compounds in tissues of harbour porpoises (Phocoena phocoena). Harbour porpoises have relatively long life spans, are common cetaceans in the North Sea, a heavily polluted area, and are known to be very sensitive to pollution. Models developed for all compounds (some PCBs and PBDEs) were evaluated using existing datasets from the literature and from analyses performed by GC-MS, the latter being obtained from stranded porpoises in the Black Sea and the North Sea over a period of 18 years (1990–2008) to assess spatial and temporal trends in bioaccumulation of the respective PCBs and PBDEs. We demonstrate that PBPK models are a feasible computational approach that can be used as a non-destructive tool for predicting the chemical pollution status of the marine mammals

Overview of the Current State-of-the-Art for Bioaccumulation Models in Marine Mammals

Information regarding the (toxico)kinetics of a chemical in organisms can be integrated in mathematical equations thereby creating bioaccumulation models. Such models can reconstruct previous exposure scenarios, provide a framework for current exposures and predict future situations. As such, they are gaining in popularity for risk assessment purposes. Since marine mammals are protected, the modeling process is different and more difficult to complete than for typical model organisms, such as rodents. This review will therefore discuss the currently available models for marine mammals, address statistical issues and knowledge gaps, highlight future perspectives and provide general do’s and don’ts

Toxicology of marine mammals: new developments and opportunities

It is widely recognized that marine mammals are exposed to a wide variety of pollutants, with a weight of evidence indicating impacts on their health. Since hundreds of new chemicals enter the global market every year, the methods, approaches and technologies used to characterize pollution levels or impacts are also in a constant state of flux. However, legal and ethical constraints often limit the type and extent of toxicological research being carried out in marine mammals. Nevertheless, new and emerging in vivo, in vitro as well as in silico research opportunities abound in the field of marine mammal toxicology. In the application of findings to population-, species-, or habitat-related risk assessments, the identification of causal relationships which inform source apportionment is important. This, in turn, is informed by a comprehensive understanding of contaminant classes, profiles and fate over space and time. Such considerations figure prominently in the design and interpretation of marine mammal (eco)toxicology research. This mini-review attempts to follow the evolution behind marine mammal toxicology until now, highlight some of the research that has been done and suggest opportunities for future research. This Special Issue will showcase new developments in marine mammal toxicology, approaches for exposure-effect research in risk assessment as well as future opportunities

Concentrations of legacy persistent organic pollutants and naturally produced meo-Pbdes in dugongs (Dugong dugon) from Moreton Bay, Australia

Dugongs (Dugong dugon)are an iconic and strictly herbivorous species. They inhabit coastal areas, which brings them in contact with urban and agricultural pollutant sources, yet their exposure and susceptibility to environmental pollutants is still largely unknown. The goal of this study was to investigate the presence of several legacy compounds such as polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs)and pesticides as well as naturally produced MeO-PBDEs in male and female dugongs from Moreton Bay (n = 24), a semi-enclosed embayment close to Australia's third largest city, Brisbane. Results show that concentrations of all investigated compounds are low in general

PCBs, PBDEs AND THEIR HYDROXYLATED METABOLITES IN SERUM OF FREE-RANGING HARBOUR SEALS (PHOCA VITULINA): LEVELS AND PROFILES

The objective of the present study was to investigate the levels and profiles of PCBs, PBDEs and their hydroxylated metabolites in blood of free-ranging harbour seals in order to elucidate the metabolism of PCBs and PBDEs

Bioaccumulation of organohalogenated compounds in sharks and rays from the southeastern USA

Organohalogenated compounds are widespread in the marine environment and can be a serious threat to organisms in all levels of aquatic food webs, including elasmobranch species. Information about the concentrations of POPs (persistent organic pollutants) and of MeO-PBDEs (methoxylated polybrominated diphenyl ethers) in elasmobranchs is scarce and potential toxic effects are poorly understood. The aims of the present study were therefore to investigate the occurrence of multiple POP classes (PCBs, PBDEs, DDXs, HCB, CHLs) and of MeO-PBDEs in various elasmobranch species from different trophic levels in estuarine and marine waters of the southeastern United States. Overall, levels and patterns of PCBs, PBDEs, DDXs, HCB, CHLs and of MeO-PBDEs varied according to the species, maturity stage, gender and habitat type. The lowest levels of POPs were found in Atlantic stingrays and the highest levels were found in bull sharks. As both species are respectively near the bottom and at top of the trophic web, with juvenile bull sharks frequently feeding on Atlantic stingrays, these findings further suggest a bioaccumulation and biomagnification process with trophic position. MeO-PBDEs were not detected in Atlantic stingrays, but were found in all shark species. HCB was not found in Atlantic stingrays, bonnetheads or lemon sharks, but was detected in the majority of bull sharks examined. Comparison with previous studies suggests that Atlantic stingrays may be experiencing toxic effects of PCBs and DDXs on their immune system. However, the effect of these compounds on the health of shark species remains unclear

Maternal transfer of organohalogenated compounds in sharks and stingrays

Elasmobranchs can bioaccumulate considerable amounts of persistent organic pollutants (POPs) and utilize several reproductive strategies thereby influencing maternal transfer of contaminants. This study provides preliminary data on the POP transfer from pregnant females to offspring of three species (Atlantic stingrays, bonnethead, blacktip sharks) with different reproduction modes (aplacental, placental viviparity). Polychlorinated biphenyl (PCB) levels were generally higher than any other POPs. Stingrays and blacktip shark embryos contained the lowest POP concentrations while bonnetheads and the blacktip adult female had the highest concentrations. Results suggest that are more readily transferred from the mother to the embryo compared to what is transferred to ova in stingrays. Statistically significant differences in levels of selected POPs were found between embryos from the left and right uterus within the same litter as well as between female and male embryos within the same litter for bonnetheads, but not for the blacktip sharks