Persistent organochlorines (OC) contaminants, including polychlorinated biphenyl (PCB) congeners, Dichlorophenyltrichloroethane (DDT)- and chlordane (CHL) related compounds, hexachlorocyclohexanes (HCH) isomers and chlorobenzenes (CBz) were determined in blubber of harp seals (Phoca groenlandica), ringed seals (Phoca hispida) and bearded seals (Eringnathus barbatus) as well as in fishes and invertebrates from the White Sea, in northwest Russia. Highest summation operator PCB and summation operator DDT concentrations were found in samples from two male bearded seals (means of 4150 ng/g lw and 3950 ng/g lw, respectively). Female harp seals had mean summation operator PCB and summation operator DDT concentrations of 1070+/-504 ng/g lw and 619+/-328 ng/g lw, respectively. Male and female adult ringed seals had similar mean summation operator PCB concentrations as harp seals (955+/-385 ng/g lw and 999+/-304 ng/g lw, respectively). summation operator CHL concentrations ranged from 63+/-29 ng/g lw in blubber of female adult ringed seals, to 322+/-156 ng/g lw in adult harp seals and averaged 465 ng/g lw in bearded seals. HCH isomers, mirex and chlorobenzenes were detected in all seal samples but were present at lower levels than summation operator CHL, summation operator DDT and summation operator PCB. Concentrations of summation operator CHL, summation operator DDT and summation operator PCB in ringed seals from the White Sea were within the range reported for the Barents Sea but lower than in ringed seals from the Kara Sea. Temporal trends were investigated by comparing concentrations of OCs in blubber of harp seal pups collected in 1992 with pups of the same age collected in 1998. The declines over the 6 year period ranged from approximately 33% for summation operator DDT to 60% for summation operator PCB. These declines are consistent with reports of declining concentrations summation operator DDT in seawater from the White Sea and inflowing rivers in the 1980's and early 1990s. The major OC contaminants in fishes from the White Sea were DDT-related compounds and PCBs. Navaga (Eleginus navaga) had the highest concentrations of the 5 fish species studied with mean summation operator PCB of 41+/-6 ng/g wet wt. while lowest mean concentrations were present in cod muscle (16+/-8 ng/g ww). Concentrations of hexachlorobenzene (HCB), DDT, CHL-related compounds and PCB congeners were strongly correlated with trophic level of the organisms assigned using delta(15)N values, while beta-HCH, gamma-HCH and cis-chlordane showed no relationship with trophic level. Food web magnification factors (FWMFs) for p,p'-DDE, alpha-HCH, oxychlordane and trans-nonachlor the White Sea were similar to those from marine food webs in the Barents Sea and the Canadian arctic, while FWMFs for HCB and PCBs were generally lower. Overall the results suggest that the White Sea marine food differs in terms of the availability of contaminants in comparison to studies of open ocean arctic food webs due to proximity to urban/industrial areas and greater importance of benthic food sources.
To trace the biomagnification of organochlorines in marine food chains near Svalbard, which may lead to the high organochlorine concentrations in top predators from the area, we compared concentrations and patterns of organochlorines in selected taxa. The pelagic crustaceans, Calanus spp. (copepods), Thysanoessa spp. (euphausiids), Parathemisto libellula (amphipod), and the fish species, Boreogadus saida (polar cod) and Gadus morhua (cod) were selected to represent the lower trophic levels in the food web. Four seabird species were chosen at the higher trophic levels, Uria lomvia (Brünnich's guillemot), Cepphus grylle (black guillemot), Rissa tridactyla (black-legged kittiwake) and Larus hyperboreus (glaucous gull). We found low concentrations of the organochlorines sigma hexachlorocyclohexanes (sigma HCHs), hexachlorobenzene (HCB), sigma Chlordanes, sigma DDTs and sigma polychlorinated biphenyls (sigma PCBs) in crustaceans (11-50 ng g-1 lipid wt.) and fish (15-222 ng g-1 lipid wt.). In seabirds, the organochlorine concentrations biomagnified one to three orders of magnitude dependent on species and compound class. Glaucous gulls had the highest concentrations of all organochlorines. The organochlorine levels in all taxa except glaucous gull were comparable to those recorded in similar species in the Canadian Arctic. The organochlorine pattern changed from crustaceans and fish to seabirds. Moving up the food chain, the relative contribution of sigma HCHs, HCB and sigma Chlordanes decreased, and the relative contribution of sigma DDTs, sigma PCBs, persistent compounds and metabolites increased. The results reflected trophic transfer of organochlorines along the food chain as well as different elimination potentials due to direct diffusion in crustaceans and fish, and higher contaminant metabolic activity in seabirds.
Environmental Conservation Division, Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Seattle, WA 98112, USA. firstname.lastname@example.org
Gray whales are coastal migratory baleen whales that are benthic feeders. Most of their feeding takes place in the northern Pacific Ocean with opportunistic feeding taking place during their migrations and residence on the breeding grounds. The concentrations of organochlorines and trace elements were determined in tissues and stomach contents of juvenile gray whales that were taken on their Arctic feeding grounds in the western Bering Sea during a Russian subsistence harvest. These concentrations were compared to previously published data for contaminants in gray whales that stranded along the west coast of the US during their northbound migration. Feeding in coastal waters during their migrations may present a risk of exposure to toxic chemicals in some regions. The mean concentration (standard error of the mean, SEM) of sigmaPCBs [1400 (130) ng/g, lipid weight] in the blubber of juvenile subsistence whales was significantly lower than the mean level [27,000 (11,000) ng/g, lipid weight] reported previously in juvenile gray whales that stranded in waters off the west coast of the US. Aluminum in stomach contents of the subsistence whales was high compared to other marine mammal species, which is consistent with the ingestion of sediment during feeding. Furthermore, the concentrations of potentially toxic chemicals in tissues were relatively low when compared to the concentrations in tissues of other marine mammals feeding at higher trophic levels. These chemical contaminant data for the subsistence gray whales substantially increase the information available for presumably healthy animals.
Persistent organochlorines, such as polychlorinated biphenyls (PCBs) including coplanar congeners, DDTs, HCHs, chlordanes (CHLs), and HCB, were determined in the blubber of Caspian seals (Phoca caspica) and their fish diet (Rutilus sp.) collected in 1993 from the northern Caspian Sea, Russia. Notable concentrations of DDTs and HCHs were found at mean values of 19 and 1.3 microg/g on wet-weight basis in adult male seals, respectively. PCB pollution in Caspian seals was not so considerable compared with those of seals that suffered mass mortality. Less gender difference of organochlorine residue levels in adult animals implies less excretion of organochlorines from the body of adult females through lactation and gestation, probably due to the higher rate of pregnancy failure. Immature seals had a wide range of organochlorine concentrations, which decreased as body length increased, suggesting dilution. Caspian seals can be considered to have higher degradation capacity for coplanar PCBs. Mean TEQs (2,3,7,8-TCDD toxic equivalents) for non-, mono- and di-ortho coplanar PCBs was 51 pg/g on wet-weight basis, which was lower than those in seals that have suffered mass mortality, but comparable to those found in Arctic seals.
Four halogenated dimethyl bipyrroles (HDBPs), hypothesized to be naturally produced, were quantitated in marine mammal blubber from a number of species obtained from various locations worldwide. HDBPs were found in samples from all locations studied. Concentrations of total HDBPs (SigmaHDBPs) ranged from 0.4 ng/g lipid weight in ringed seals (Phoca hispida) from the White Sea to 2,540 ng/g lipid weight in Dall's porpoise (Phocoenoides dalli) from the northwestern North Pacific Ocean. At their highest levels, SigmaHDBPs made up 11% of the total quantitated organohalogen body burden of adult male Dall's porpoises. In two beluga (Delphinapterus leucas) data subsets, it was found that males contained significantly higher concentrations of SigmaHDBPs than females. No significant effects of age or sex on SigmaHDBPs were observed in harbor seal (Phoca vitulina) and bowhead whale (Balaena mysticetus) data subsets. The geographical distribution of concentrations did not resemble that of the ubiquitous anthropogenic organohalogen, polychlorinated biphenyl congener CB-153. Higher concentrations of HDBPs and different patterns of congeners were observed in samples from Pacific as opposed to non-Pacific Ocean influenced environments. Concentrations of HDBPs in beluga from the Arctic and St. Lawrence River were similar. Their high abundance in north Pacific Ocean biota and widespread occurrence suggest that HDBPs undergo extensive transport from a source located primarily in the Pacific Ocean. Evidence from HDBP congener patterns indicates that both ocean currents and atmospheric transport likely play a role in the movement of HDBPs. These results imply that HDBPs and anthropogenic organohalogens have different sources and support the natural production hypothesis.
Bitumen extraction from the oil sands of northern Alberta produces large volumes of process-affected water that contains substances toxic to wildlife. Recent monitoring has shown that tens of thousands of birds land on ponds containing this water annually, creating an urgent need to understand its effects on bird health. We emulated the repeated, short-term exposures that migrating water birds are thought to experience by exposing pekin ducks (Anas platyrhynchos domestica) to recycled oil sands process-affected water (OSPW). As indicators of health, we measured a series of physiological (electrolytes, metabolites, enzymes, hormones, and blood cells) and toxicological (metals and minerals) variables. Relative to controls, juvenile birds exposed to OSPW had higher potassium following the final exposure, and males had a higher thyroid hormone ratio (T3/T4). In adults, exposed birds had higher vanadium, and, following the final exposure, higher bicarbonate. Exposed females had higher bile acid, globulin, and molybdenum levels, and males, higher corticosterone. However, with the exception of the metals, none of these measures varied from available reference ranges for ducks, suggesting OSPW is not toxic to juvenile or adult birds after three and six weekly, 1 h exposures, but more studies are needed to know the generality of this result.
Concentration of three heavy metals (mercury (Hg), lead, (Pb), and cadmium, (Cd)) and one metalloid (arsenic [As]), were determined by atomic absorption spectrophotometry in five tissues (muscles, liver, kidneys, gills, and gonads) of five fish species (carp-Cyprinus carpio, tench-Tinca tinca, sval-Leuciscus svallizi, gray mullet-Mugil cephalus, and eel-Anguilla anguilla) taken out from the end fIow (last 20 km) of the river Neretva, south Croatia, in the wider region of town Metkovic, during the summer of the year 2003. Only Cd concentration in all fish types was higher than the maximal allowed concentration (MAC) in Croatia, but its concentration in muscles reaches this value only in four samples. However, in carp, tench, and mullet, Cd concentrations higher than MAC in some other countries were found. Hg concentration is much lower than MAC in the most countries. Pb is found in higher quantities only in carp, some values reaching MAC in Germany, and many values being higher than MAC in Denmark (with exception of gonads). As concentrations are much lower than MAC in all countries, but it seems that mullet tends to accumulate this metalloid, especially in the muscles. Therefore, in several samples, muscle As concentration in mullet reached half of the MAC value in the most countries. Of the analyzed fish types, eel, containing the smallest quantities of heavy metals, is recommended for human diet, while carp, consumed most frequently by local inhabitants and numerous tourists, shares with mullet the last place on the recommendation list. Also, it is suggested that meals prepared with analyzed fish sorts should not contain some inner organs (kidneys and liver), as well as gills (alternatively, the whole head). Our final conclusion is that fish types eating predominantly meat contain less heavy metal in their tissues, and therefore are more suitable for human diet.
Certain populations of killer whales (Orcinus orca) have been extensively studied over the past 30 years, including populations that use Puget Sound, WA, the inside waters of British Columbia, Southeastern Alaska and Kenai Fjords/Prince William Sound, Alaska. Two eco-types of killer whales, 'transient' and 'resident', occur in all of these regions. These eco-types are genetically distinct and differ in various aspects of morphology, vocalization patterns, diet and habitat use. Various genetic and photo-identification studies of eastern North Pacific killer whales have provided information on the male-female composition of most of these resident pods and transient groups, as well as the approximate ages, reproductive status and putative recruitment order (birth order) of the individual whales. Biopsy blubber samples of free-ranging resident and transient killer whales from the Kenai Fjords/Prince William Sound, AK region were acquired during the 1994-1999 field seasons and analyzed for selected organochlorines (OCs), including dioxin-like CB congeners and DDTs. Concentrations of OCs in transient killer whales (marine mammal-eating) were much higher than those found in resident animals (fish-eating) apparently due to differences in diets of these two killer whale eco-types. Certain life-history parameters such as sex, age and reproductive status also influenced the concentrations of OCs in the Alaskan killer whales. Reproductive female whales contained much lower levels of OCs than sexually immature whales or mature male animals in the same age class likely due to transfer of OCs from the female to her offspring during gestation and lactation. Recruitment order also influenced the concentrations of OCs in the Alaskan killer whales. In adult male residents, first-recruited whales contained much higher OC concentrations than those measured in non-first-recruited (e.g. second recruited, third recruited) resident animals in the same age group. This study provides baseline OC data for free ranging Alaskan killer whales for which there is little contaminant information.
Polybrominated diphenyl ethers (PBDEs) were determined in blubber samples of 54 stranded adult beluga whales (Delphinapterus leucas) collected between 1988 and 1999 in the St. Lawrence Estuary (SLE), Quebec, Canada. Summed concentrations of 10 PBDE congeners (sigmaPBDEs) measured in beluga samples varied between 20 and almost 1000 ng/g wet weight. According to the PBDE concentrations in marine mammals reported in the scientific literature, SLE belugas appear to be relatively lightly contaminated. Only a few predominant congeners (namely, PBDE-47, -99, and -100) represent on average more than 75% of sigmaPBDEs in SLE belugas. The accumulation of sigmaPBDEs in both male and female belugas showed significant exponential increase throughout the 1988-1999 time period. The time necessary for beluga to double their blubber concentration of the most prevalent PBDE congeners was no longer than 3 years. The PBDE temporal changes reported in this study are generally faster but in agreement with the trend observed in other organisms collected in Canada, such as lake trout (Salvelinus namaycush) from the Great Lakes, ringed seal (Phoca hispida), and beluga whale from the Canadian Arctic. Some changes in the pattern of PBDEs in belugas were also observed during the time period investigated. The recent and important increase of PBDE levels in SLE belugas could explain the unexpected lack of statistical difference in PBDE contamination between males and females. This suggests that to date PBDEs tend to be accumulated by both male and female belugas, masking the elimination of PBDEs by females through post-natal transfer to their offspring. This study confirms that the growing use of PBDEs as flame retardants has resulted in rising contamination of Canadian aquatic environments. Additional studies are needed to assess the toxicological implications of the PBDE tissue levels found in SLE belugas.
The concentrations of mercury (Hg), cadmium (Cd), lead (Pb) and selenium (Se) were determined in liver, kidney and muscle samples from 20 Baltic ringed seals (Phoca hispida botnica) (3-32 years), and from 17 ringed seals (Phoca hispida) (0-20 years) from Svalbard, in the Arctic. The concentrations of Hg and Se were considerably higher in the Baltic ringed seals, but the Cd concentrations lower than in the Svalbard ringed seals. There was no big geographical difference with respect to Pb concentrations. Se and Hg concentrations showed a significant positive correlation in both regions. By comparison with earlier studies on Baltic seals, the metal concentrations have remained at the same level since the 1980s. Of the metals we studied, only the level of Hg in Baltic ringed seals can be considered high (mean 53 mg/kg, range 6.5-124 mg/kg wet wt. for liver), but probably not high enough to cause metal intoxication. No pathological changes associated with metal intoxication were observed in the seals.