High Concentrations Of Organochlorines Research Articles

Review of organohalogen toxicants in fish from the Gulf of Finland

Abstract A literature survey identified 30 articles providing data on the concentrations of organohalogen compounds in fish caught from the Gulf of Finland: polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and biphenyls (PCBs), the chlorinated pesticide DDT and polybrominated diphenylethers (PBDEs). Results were found for 14 fish species in total, but mainly for herring (Clupea harengus), salmon (Salmo salar) and sprat (Sprattus sprattus), and the oldest data were for PCBs, from 1975. PCBs and PCDDs were the most prevalent organohalogens in the Gulf of Finland compared to other areas of the Baltic Sea. In particular, more local fish species and benthic feeders caught from the eastern parts of the Gulf of Finland appear to contain higher concentrations of organochlorines than those from the western parts. The concentration of dioxins plus dioxin-like PCBs as WHO-TEQPCDD/F + PCB in herring has demonstrated a decreasing trend since the late 1970s. However, the maximum allowable concentration of WHO-TEQPCDD/F + PCB in fish set by the EC was exceeded in all salmon and older herring specimens and in some whitefish (Coregonus lavaretus), bream (Abramis brama), sea trout (Salmo trutta) and flounder (Platichthys flesus). The respective limit concentration for fish used as animal feed was exceeded in most of the fish samples.

A marine sink for chlorine in natural organic matter

Chloride is abundant in oceans, but is relatively unreactive. Spectroscopic imaging reveals the presence of a chloride sink in organochlorine compounds that can be produced abiotically or by phytoplankton. Chloride—the most abundant ion in sea water1—affects ocean salinity, and thereby seawater density and ocean circulation. Its lack of reactivity gives it an extremely long residence time2. Other halogens are known to be incorporated into marine organic matter3,4,5. However, evidence of similar transformations of seawater chloride is lacking, aside from emissions of volatile organochlorine by marine algae6,7,8. Here we report high organochlorine concentrations from 180 to 700 mg kg−1 in natural particulate organic matter that settled into sediment traps at depths between 800 and 3,200 m in the Arabian Sea, taken between 1994 and 1995. X-ray spectromicroscopic imaging of chlorine bonding reveals that this organochlorine exists primarily in concentrated aliphatic forms consistent with lipid chlorination, along with a more diffuse aromatic fraction. High aliphatic organochlorine in particulate material from cultured phytoplankton suggests that primary production is a source of chlorinated organic matter. We also found that particulate algal detritus can act as an organic substrate for abiotic reactions involving Fe2+, H2O2 or light that incorporate chlorine into organic matter at levels up to several grams per kilogram. We conclude that transformations of marine chloride to non-volatile organochlorine through biological and abiotic pathways represent an oceanic sink for this relatively unreactive element.

Anthropometric, socioeconomic, and maternal health determinants of placental transfer of organochlorine compounds

The aim of this study was to relate placental transfer, quantified by the cord to maternal serum concentration ratio (C/M), of five organochlorine pesticides (OCP) hexachlorobenzene (HCB), β-hexachlorocyclohexane (β-HCH), γ-hexachlorocyclohexane (γ-HCH) , p,p'-DDT, p,p'-DDE and 15 polychlorinated biphenyl (PCB) congeners (28, 52, 101, 105, 114, 118, 123(+149), 138(+163), 153, 156(+171), 157, 167, 170, 180, and 189) to anthropometric, socioeconomic, and maternal health characteristics. We included into the study 1,134 births during the period 2002-2004 from two districts in eastern Slovakia with high organochlorine concentrations relative to other areas of the world. Only concentrations >LOD were taken into account. Variables as age, weight and height of mothers, parity, ethnicity, alcohol consumption, illness during pregnancy, smoking during pregnancy, hypertension, respiratory diseases, rheumatoid arthritis and diabetes mellitus, and birth weight were related to C/M. Results of regression analyses showed that C/M was predicted by several factors studied. Positive associations were observed for gestational alcohol consumption, fewer illnesses during pregnancy, maternal age, and maternal weight. Caucasians had a greater C/M compared to Romani for wet weight data of congeners 170 and 180 and in contrast C/M for HCB was greater in Romani. Our results show that drinking mothers compared to abstaining expose their fetuses not only to alcohol but to an increased level of several PCB congeners. A straightforward explanation of associations between C/M shifts and factors studied is very difficult, however, with regard to the high lipophilicity of OCPs and PCBs, changes in their kinetics probably reflect lipid kinetics.

Contrasting retinoid and thyroid hormone status in differentially-contaminated northern fulmar colonies from the Canadian Arctic, Svalbard and the Faroe Islands

The northern fulmar (Fulmarus glacialis) has previously been shown to accumulate a wide range, and occasionally high concentrations of organochlorines (OCs) (e.g., PCBs, chlorobenzenes, DDT- and chlordane-related compounds, dioxins and furans). The present study aimed to investigate, using a meta-analysis approach, the variations in cytochrome P450 (CYP) 1A-like enzyme induction based on ethoxyresorufin O-deethylase activity (EROD) and selected physiological variables (retinoids and thyroid hormones) in northern fulmar breeding in three differentially OC-exposed populations: Nunavut (Canadian Arctic), Svalbard (Norwegian Arctic) and the Faroe Islands. Substantially higher (roughly two-fold) OC levels were uncovered in the liver of this long-lived fulmarine petrel breeding in the Faroe Islands relative to Svalbard and Nunavut. Liver levels of PCDDs, PCDFs and non-ortho PCBs in Faroe Islands fulmars were amongst the highest reported thus far in any seabirds from the northern regions. Positive correlations were depicted in combined fulmars (all three populations) between hepatic EROD activity and concentrations of OCs, in which strongest associations were found for dioxin-like compound (PCDFs and PCDDs) and TEQ concentrations. Moreover, moderate to strong positive correlations were found between liver OC concentrations and plasma total thyroxin (TT4) levels and TT4/total triiodothyronine (TT3) level ratios, as well as strong negative correlations between the same suite of OCs and plasma TT3 levels. Hepatic OC concentrations (PCBs, PCDDs, PCDFs, HCB, p,p'-DDE and oxychlordane) also were positively correlated with hepatic retinyl palmitate levels which, in turn, were associated with a significant decrease in plasma retinol levels and somewhat unchanged liver retinol levels. The present meta-analysis investigation on northern fulmar breeding in three geographically-distant sites illustrated that OC exposure (mainly PCBs and dioxins/furans) may be associated with modulation of the thyroid and retinoid homeostasis. However, the impact of confounding environmental factors (e.g., temperature and nutritional status) on current physiological variable variations could not be ruled out, and thus any cause-effect linkages between thyroid and retinoid system perturbation and OC exposure cannot be ascertained.

Organochlorine pesticide and polychlorinated biphenyl residues in human milk from Tabriz, Iran

Human breast milk samples, collected during April 2007 in Tabriz, Iran, were analyzed for organochlorine (OC) pesticides, such as dichlorodiphenyltrichloroethane (DDT) and its metabolites, hexachlorobenzene (HCB), α, β, and γ-hexachlorocycloexane (HCH) isomers and six polychlorinated biphenyls (PCB) congeners (IUPAC Nos. 28, 52, 101, 138, 153, and 180). Organochlorine pesticides and OCB were both prevalent in the samples of human breast milk. Average concentrations of HCB, DDT, HCH, and PCB were 1020, 1930, 1660, and 690 ng g−1 lipid weight, respectively. A positive correlation was observed between concentration of OC in human breast milk and mothers age with primiparae. Women having higher OC concentrations than multiparae women suggests that these parameters influence the OC burden in lactating women. The estimated tolerable daily intakes (TDIs) of HCH, HCB and PCB solely from human breast milk were 100, 46, and 43% of samples, respectively, exceeding guideline thresholds given as TDI proposed by Health Canada. Although high daily intakes may raise concerns for possible adverse effects of OC, women in Tabriz are recommended to breastfeed due to the numerous advantages for mother and child.

Adrenocortical function of Arctic-breeding glaucous gulls in relation to persistent organic pollutants

Unpredictable changes in the environment stimulate the avian hypothalamo–pituitary–adrenal axis to produce corticosterone, which induces behavioural and metabolic changes that enhance survival in the face of adverse environmental conditions. In addition to profound environmental perturbations, such as severe weather conditions and unpredictable food shortages, many Arctic-breeding birds are also confronted with chronic exposure to persistent organic pollutants (POPs), some of which are known to disrupt endocrine processes. This study investigated the adrenocortical function of a top predator in the Arctic marine environment, the glaucous gull ( Larus hyperboreus). High concentrations of organochlorines, brominated flame retardants and metabolically-derived products in blood plasma of incubating glaucous gulls were associated with high baseline corticosterone concentrations in both sexes and a reduced stress response in males. Contaminant-related changes in corticosterone concentration occurred over and above differences in body condition and seasonal variation. Chronically high corticosterone concentrations and/or a compromised adrenocortical response to stress can have negative effects on the health of an individual. The results of the present study suggest that exposure to POPs may increase the vulnerability of glaucous gulls to environmental stressors and thus could potentially compromise their ability to adapt to the rapidly changing environmental conditions associated with climate change that are currently seen in the Arctic.

Perfluorinated, brominated, and chlorinated contaminants in a population of lesser black‐backed gulls (Larus fuscus)

AbstractProtein‐bound perfluorinated compounds (PFCs) and lipid‐soluble polybrominated diphenyl ethers (PBDEs) and organo‐chlorines (OCs) were measured in whole blood from a large number (n = 83) of breeding lesser black‐backed gulls (Larus fuscus) caught during two distinct sampling periods in a colony on the coast of northern Norway. We analyzed 14 PFCs (seven were detected in more than 75% of samples), 10 PBDEs (only BDE 47 was detected), and 27 OCs, including 12 polychlorinated biphenyl (PCB) congeners (14 OCs were detected). Median total PFC concentration was higher than median total OC concentration (43 vs 39 ng/g wet wt). Perfluorooctane sulfonate (PFOS) was the dominant PFC (mean relative contribution of PFOS to total contaminant concentration in blood [Σtotal contaminants] was 38%), whereas total PCB (26% of Σtotal contaminants) and p,p′‐DDE (2,2‐bis(4‐chlorophenyl)‐1,1‐dichloroethene; 13% of Σtotal contaminants) were the dominant OCs. No covariability was found between protein‐bound and lipid‐soluble compounds; individuals with high concentrations of PFCs did not have high concentrations of OCs or BDE 47. The concentrations of PFCs were lower in birds caught during the late sampling period compared to those of the early period, and females had lower levels of some PFCs compared with males, suggesting that females sequester fluorinated substances into eggs. For lipid‐soluble compounds, no significant sex or sampling period differences were found, except that trans‐nonachlor, cis‐nonachlor, and p,p′‐DDE concentrations were lower in birds caught during the late sampling period. The pattern of PFC compounds (relative to PFOS) and lipid‐soluble compounds (relative to PCB 153) differed between sampling periods in females but not in males. Finally, PFCs were distributed more uniformly within the population than the lipid‐soluble compounds, for which the distributions were strongly negatively skewed.

Decreased survival in pancreatic cancer patients with high concentrations of organochlorines in adipose tissue

We analysed adipose tissue concentrations of persistent organic pollutants (POPs) in 21 cases with exocrine pancreatic cancer. The comparison group consisted of 59 subjects. Significantly increased concentrations of polychlorinated biphenyls (PCBs), hexachlorobenzene (HCB), sum of chlordanes and polybrominated diphenylethers (PBDEs) were found in the cases. For 1,1,-dichloro-2,2-bis( p-chlorophenyl)-ethylene ( p,p′-DDE) no significant difference was seen. For PCBs no odds ratio (OR) could be calculated since all cases had concentration > median in controls used as a cut-off. HCB yielded OR = 53.0, 95% confidence interval (CI) = 4.64–605 and sum of chlordanes OR = 18.4, 95% CI = 2.71–124 whereas OR was not significantly increased for p,p′-DDE or PBDEs. Body mass index (BMI) at the time of tissue sampling was significantly lower for the cases. This might have influenced the results. Using BMI one year previously or decreasing the concentrations of POPs with the same percentage as weight loss among the cases did not change the results. Survival of the cases was shorter in the group with the concentration of POPs > median among cases, significantly so for the sum of PCBs (147 vs. 294 days), p,p′-DDE (134 vs. 302 days), and sum of chlordanes (142 vs. 294 days) in the high and low group, respectively. The results were based on a low number of cases and should be interpreted with caution.

PERFLUORINATED, BROMINATED AND CHLORINATED CONTAMINANTS IN A POPULATION OF LESSER BLACK-BACKED GULLS

Protein-bound perfluorinated compounds (PFCs) and lipid-soluble polybrominated diphenyl ethers (PBDEs) and organochlorines (OCs) were measured in whole blood from a large number (n = 83) of breeding lesser black-backed gulls (Larus fuscus) caught during two distinct sampling periods in a colony on the coast of northern Norway. We analyzed 14 PFCs (seven were detected in more than 75% of samples), 10 PBDEs (only BDE 47 was detected), and 27 OCs, including 12 polychlorinated biphenyl (PCB) congeners (14 OCs were detected). Median total PFC concentration was higher than median total OC concentration (43 vs 39 ng/g wet wt). Perfluorooctane sulfonate (PFOS) was the dominant PFC (mean relative contribution of PFOS to total contaminant concentration in blood [Sigmatotal contaminants] was 38%), whereas total PCB (26% of Sigmatotal contaminants) and p,p'-DDE (2,2-bis(4-chlorophenyl)-1,1-dichloroethene; 13% of Sigmatotal contaminants) were the dominant OCs. No covariability was found between protein-bound and lipid-soluble compounds; individuals with high concentrations of PFCs did not have high concentrations of OCs or BDE 47. The concentrations of PFCs were lower in birds caught during the late sampling period compared to those of the early period, and females had lower levels of some PFCs compared with males, suggesting that females sequester fluorinated substances into eggs. For lipid-soluble compounds, no significant sex or sampling period differences were found, except that trans-nonachlor, cis-nonachlor, and p,p'-DDE concentrations were lower in birds caught during the late sampling period. The pattern of PFC compounds (relative to PFOS) and lipid-soluble compounds (relative to PCB 153) differed between sampling periods in females but not in males. Finally, PFCs were distributed more uniformly within the population than the lipid-soluble compounds, for which the distributions were strongly negatively skewed.

High Concentrations of Organochlorines in a Patient with Kidney Cancer and Anorexia-cachexia Syndrome

To determine persistent organic pollutants in adipose tissue in a patient with kidney cancer. Adipose tissue was sampled from the abdominal wall during autopsy of a 75-year old man who had died from a kidney cancer. The concentrations of polychlorinated biphenyls (PCBs), p,p'-dichlorodiphenyltrichloroethane (DDE), hexachlorobenzene (HCB), chlordanes and tetrabromodiphenyl ether (TeBDE) were determined on lipid basis. For comparison results from 29 male population based subjects aged 70-80 years were used. All concentrations except for TeBDE were very high in the patient; sum of PCBs 18 808 ng/g fat (median for controls 997), DDE 14 183 (median for controls 751), HCB 424 (median for controls 46), and sum of chlordanes 2 389 (median for controls 62). The patient lost weight from 80 kg to 48 kg when he died, which may have contributed wholly or partly to the very high concentrations of organochlorines. Changes in weight must be recorded in cancer patients and the concentrations of persistent organic pollutants should be normalized to weight. The concentrations in this patient were 10- to almost 40-times higher than in the controls. Such very high concentrations may give clinical symptoms in the final stage of a wasting cancer patient.

Low hepatic ethoxyresorufin‐o‐deethylase activity correlates with high organochlorine concentrations in Atlantic tomcod from the Canadian east coast

A suppression of hepatic ethoxyresorufin-O-deethylase (EROD) activity was reported recently in large-sized Atlantic tomcod (Microgadus tomcod) from the St. Lawrence Estuary (SLE; QC, Canada), possibly related to chronic exposure to persistent contaminants and/or to emaciation. In the present study, hepatic concentrations of organochlorine contaminants and biological responses were measured in female tomcods from three estuaries located on the Canadian east coast: The SLE, the Miramichi (ME), and the Richibucto (RE) Rivers Estuaries (NB, Canada). Tomcods from the SLE had higher hepatic concentrations of organochlorine contaminants than tomcods from the ME and RE. For example, concentrations of polychlorinated biphenyls (PCBs, lipid wt) were 2.5 to 4 times higher, and concentrations of mirex and chlordanes were 6 times higher, in tomcods from the SLE than in tomcods from the other sites. Concentrations of polycyclic aromatic hydrocarbons (PAHs) metabolites in the bile did not differ among sites. The pattern of biological responses differed markedly between the SLE and the two other sites. Tomcods from the SLE had 1.5 times higher concentrations of DNA adducts and 2 times higher rates of hepatocellular proliferation, but 20 times lower hepatic EROD activity, than tomcods from the ME and RE. Lipid content was not correlated with EROD activity, indicating that low hepatic lipid content alone does not cause suppression of EROD activity in Atlantic tomcod. In contrast, for the three sites combined, EROD activity decreased as concentrations of PCBs increased. Within sites, hepatic PCB concentrations increased as lipid content decreased. This study supports the hypothesis that low EROD activity in SLE tomcods is related to chronic exposure to organochlorine contaminants.

Spatial trends and factors affecting variation of organochlorine contaminants levels in Canadian Arctic beluga ( Delphinapterus leucas)

Organochlorine pesticides and PCBs were analysed in blubber from beluga ( Delphinapterus leucas), or white whales, collected at 15 sites in the Canadian Arctic between 1993 and 2001. The objective of the study was to define and interpret the spatial trends of major organic contaminants in northern beluga in terms of sources and transport pathways, and the biological factors influencing accumulation. When compared on a lipid weight basis, the concentrations of β-HCH, cis-CHL and ΣCHL, cis-nonachlor, heptachlor epoxide and p, p'-DDT were significantly higher in males than females at all five sites in the eastern Arctic where the two sexes were harvested. The differences were attributed to losses from the females during fetal development and lactation as reported in previous studies. Major compounds increased with age in males at most sites, however the lack of a significant increase with age at some sites was in part due to high organochlorine concentrations in young year classes (2–5 years), particularly at eastern sites such as Iqaluit and Pangnirtung. Lower concentrations of ΣHCH and ΣDDT compounds in young males in 2001 relative to 1995 at Hendrickson Island could be due to declining levels in the environment, changes in the diet, or differences in organochlorine loads transferred from the female after birth. Age-corrected least square mean concentrations in males showed significantly higher levels of many compounds, such as p, p'-DDE and ΣCHB, at south Baffin Island sites than those in the west. Two notable exceptions were HCBz and β-HCH which were higher in the west. Methoxyclor was detected in males at Sanikiluaq (58 ng g − 1 ) and in both sexes at Kimmirut, but at no other sites. Principal component analysis grouped the 16 sites into five major groupings based on the similarity of normalised organochlorine pesticide and PCB levels. Sites from the western Arctic were grouped by higher proportions of HCBz, β-HCH and γ-HCH and higher chlorinated PCBs. Endosulfan and α-HCH comprised a larger proportion of total organochlorine residues in the northern Hudson Bay sites, while methoxychlor, chlordane compounds and octachlorobiphenyls were enriched at Sanikiluaq in eastern Hudson Bay. The analysis showed that the relative amounts of several key compounds are similar in the beluga stocks over large spatial areas (i.e. eastern versus western sites), however, some stocks have distinct fingerprints which can be used to differentiate them from adjacent stocks. Ratios of major HCH isomers largely corresponded with air and surface water measurements conducted during the 1990s, but low α- / β- and α- / γ-HCH ratios in all three western Arctic collections indicate rapid losses of the α-isomer from the food web, proportionately higher β- and γ-isomers in the Beaufort Sea, or a combination of the two processes. Chlordane residue patterns generally correspond to those from previous studies, however, interpretation of spatial trends are difficult due to the aging of the probable sources in the south, possible atmospheric input from new sources and complex transport pathways.

Effect of organochlorine contaminants and individual biological traits on blubber retinoid concentrations in bottlenose dolphins (Tursiops truncatus)

Here we assessed retinoids as biomarkers of contaminant exposure by studying whether the sex, age, lipid content and organochlorine concentrations of bottlenose dolphins induced variation in retinoid status and its deposition in blubber. Blubber samples were collected from 47 individuals of known age and gender from Sarasota Bay in June 2000 and 2001. The sample included a representative cross-section of the resident dolphin community, with ages ranging from 2 to 50 years. Organochlorine levels showed the age- and sex-related variation commonly observed in other species, with concentrations increasing in youngsters of both sexes and in adult males, and decreasing in adult females after the onset of maturity. Blubber lipid content was low in the overall population and significantly decreased with age in adult males. Retinoid blubber concentrations were comparable to other odontocete species previously studied, and were strongly determined by lipid content. As a consequence of the latter, retinoid concentration was observed to decrease with age in adult males. This effect could not be statistically dissociated from the negative correlation observed between levels of organochlorines and retinoid blubber concentration. Consequently, we could not clarify whether high organochlorine loads in this population lowered retinoid concentrations or, conversely, whether depleted lipid reserves were indeed responsible for the high organochlorine concentrations and the low retinoid levels detected in blubber. With the current knowledge, both options should be considered and investigated, with initial focus on male dolphins.

Organochlorines Affect the Steroid Hormone Cortisol in Free-Ranging Polar Bears (Ursus maritimus) at Svalbard, Norway

Since the polar bear (Ursus maritimus) is among the most highly organochlorine-contaminated species of the Arctic mammals, there is growing concern that in addition to the natural stressors in the polar bear's environment, several organochlorines (OCs) may be able to change basic endocrine pathways. Alterations in the hypothalamic–pituitary–adrenal (HPA) axis may affect plasma cortisol concentrations and inhibit physiological processes involved in the maintenance of homeostasis in a way that may endanger the animal's health. Between 1995 and 1998, samples were collected from 121 male and 130 female free-ranging polar bears from the Svalbard area. The aim of the study was to investigate relationships between plasma cortisol concentrations, biological factors, and OCs. The variation in plasma cortisol concentrations was determined for the total sample. Axillary girth and body mass together with their interactions explained more than 50% of the variation in the plasma cortisol concentration. The sum of pesticides (Σpesticides) combined with the sum of polychlorinated biphenyls (ΣPCBs) and their interactions explained over 25% of the variation in the cortisol concentration. Although Σpesticides contributed negatively and ΣPCBs contributed positively to the variation in the plasma cortisol, the over-all contribution of the OCs to the plasma cortisol variation was negative. Despite the complexity on stress responses and the interactions with environmental factors, this study demonstrated that high concentrations of OCs in polar bears might alter plasma cortisol concentrations.

Organochlorines Affect the Major Androgenic Hormone, Testosterone, in Male Polar Bears (Ursus Maritimus) at Svalbard

Normal sexual development and subsequent reproductive function are dependent on appropriate testosterone production and action. The regulation of steroid hormones, including androgens, can be influenced by both biological and environmental factors, including environmental chemicals. Concentrations of organochlorines are considerably greater in Svalbard polar bears than in polar bears from other regions. Between 1995 and 1998, samples were collected from 121 male polar bears (Ursus maritimus) from the Svalbard area. In this study, testosterone concentration variations were described for male polar bears during different seasons and for all age groups. To study possible relationships between plasma testosterone concentrations and biological factors, such as age, axial girth, and extractable plasma fat, and organochlorine contaminants including hexachlorocyclohexanes, hexachlorobenzene, chlordanes, p,p′–DDE, and 16 individual polychlorinated biphenyl (PCB) congeners, identical statistical analyses were performed on the total population and a subsample of reproductively active adults. Of the biological factors, axial girth showed a significant positive relationship and percentage extractable fat and a significant negative relationship with the testosterone concentrations. Both the Σpesticides and ΣPCBs made significant negative contributions to the variation of the plasma testosterone concentration. The continuous presence of high concentrations of organochlorines in male polar bears throughout their life could possibly aggravate any reproductive toxicity that may have occurred during fetal and early postnatal development.

How Will Global Climate Change Affect Risks from Long-Range Transport of Persistent Organic Pollutants?

Climate change and climate variability affect risk from contaminants by changing exposure to chemicals, either through the alteration of pathways or through alteration of environmental concentrating mechanisms. The alteration of pathways is affected by changing the balance between transport and deposition. Although the influence of temperature on multimedia partitioning can be modelled successfully, estimating alteration in other climate components such as distribution and form of precipitation provides a much greater challenge. To understand how climate change affects contaminant concentrations, we distinguish two types of environmental concentrating processes — solvent switching and solvent depletion. The first process, which is simply chemical partitioning, runs spontaneously toward equilibrium. This process alone can explain hemispheric-scale distributions of hexachlorocyclohexane, which partitions strongly into water, and high concentrations of organochlorines at the bottom of aquatic foodwebs. The latter process involves the maintenance of contaminant burdens during the loss of solvent, with the aquatic foodweb providing one of the better-known examples. Solvent reducing processes can produce contaminant concentrations well above thermodynamic equilibrium with a number of important examples provided by phase changes in water (freezing, snow melting). These solvent-reducing processes, which are poorly studied, provide some of the best circumstances for climate change to produce alteration in persistent organic pollutants exposure pathways.

Organochlorine and organotin compounds in Caspian seals ( Phoca caspica) collected during an unusual mortality event in the Caspian Sea in 2000

Polychlorinated biphenyls (PCBs), organochlorine pesticides and organotin compounds were determined in the blubber and liver of Caspian seals ( Phoca caspica) found stranded on the coast of the Caspian Sea during an outbreak of canine distemper virus (CDV) in 2000. Among organochlorines analyzed, DDTs were the most dominant contaminants with concentrations ranging from 6.3 to 470 μg/g on a lipid-weight basis. Caspian seals collected in 2000 during the epizootic had higher concentrations of organochlorines than healthy individuals sampled in 1998. However, the blubber layer was generally thinner in the seals collected in 2000 than those in the previous surveys. Although compositions of organochlorine pesticides in seals suggested that the contamination status in the Caspian Sea is improving, the levels found in Caspian seals in 2000 were comparable to those in other marine mammals that have suffered from epizootics. This implies that the present status of contamination found in Caspian seals poses a risk of immunosuppression. Concentrations of butyltin compounds in livers of seals ranged from 0.49 to 17 ng/g on a wet-weight basis and octyltin compounds were below limit of detection in all the samples analyzed, suggesting less contamination by organotin compounds in the Caspian Sea.

Patterns of incubation and nest‐site attentiveness in relation to organochlorine (PCB) contamination in glaucous gulls

SummaryAlthough experimental studies show that organochlorines (OC) can affect bird behaviour, field assessments are invariably confounded by ecological differences between contaminated and uncontaminated sites. The behaviour of individual birds in the field has rarely been related to the contaminant burden.We examined individual patterns of incubation and nest‐site attentiveness in relation to OC burden, measured as polychlorinated biphenyl (PCB) concentration in the blood, of 27 glaucous gullsLarus hyperboreusin two breeding areas at Bear Island, in the north‐eastern Atlantic.Blood PCB concentrations ranged from 52 ng g‐1to 1079 ng g‐1(wet weight). There were significant differences between the two breeding areas, and females had significantly lower concentrations than males.Gull behaviour differed significantly between breeding areas and sexes independently of PCB. Females incubated more than males (54% vs. 46%) but spent more time away from the nest site than males, both overall (23% vs. 12%) and when not incubating (50% vs. 21%). They were also absent for longer periods (4·5 vs. 2·8 h). Moreover, length of incubation bouts (6·4 vs. 4·4 h), the amount of time absent from the nest site when not incubating (51% vs. 25%) and length of absences (5·6 vs. 1·8 h) differed between breeding areas, probably due to different feeding specializations.After controlling for these area and sex effects, the proportion of time absent from the nest site when not incubating, and the number of absences, were both significantly related to blood concentration of PCB.Increased absence from the nest site in individual glaucous gulls with high blood concentrations of OC suggests effects on reproductive behaviour. We speculate that endocrine disruption or neurological effects might be involved, leading to increased energetic costs during incubation and reduced reproductive output.

Biomagnification of organochlorines along a Barents Sea food chain

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 Σhexachlorocyclohexanes (ΣHCHs), hexachlorobenzene (HCB), ΣChlordanes, ΣDDTs and Σpolychlorinated biphenyls (ΣPCBs) 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 ΣHCHs, HCB and ΣChlordanes decreased, and the relative contribution of ΣDDTs, ΣPCBs, 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.

Exposure of Inuit in Greenland to Organochlorines Through the Marine Diet

High organochlorine concentrations have been found among the Inuit in eastern Canada and in Greenland. The present study was undertaken to assess the exposure to organochlorines in relation to age, sex, and diet in a general population sample of Inuit from Greenland. Survey data and plasma concentrations of 14 polychlorinated biphenyl (PCB) congeners and 16 pesticides, including 5 toxaphene congeners, were recorded in a random population survey of 408 adult indigenous Greenlanders. In a two-stage design, the survey response rate was 66%, and 90% of those randomly selected for blood testing participated. This was equivalent to an overall response rate of 59%. The median plasma concentration of the sum of PCB congeners was 13.3 µg/L; the lipid-adjusted value was 2109 µg/kg. The PCB concentration was twice as high as among the Inuit of Nunavik, Canada, 25 times higher than in a control group from southern Canada, and several times higher than the values found in European studies. Concentrations were similarly elevated for all PCB congeners and pesticides. The PCB congener pattern was similar to previous observations from the eastern Canadian Arctic and Greenland. Concentrations showed statistically significant positive associations with age, marine diet, and male sex in multiple linear regression analyses. The exceptionally high plasma concentrations of several organochlorines among the Inuit of Greenland are attributed to a lifelong high intake of seafood, in particular marine mammals. Concentrations of PCB adjusted for the consumption of marine food increased until approximately 40 yr of age, which is equivalent to the birth cohorts of the early 1950s. The age pattern indicates that bioaccumulation of PCB started in the 1950s, which is a likely date for the introduction of the compounds into the Arctic environment.