A screening of persistent organohalogenated contaminants in hair of East Greenland polar bears

In this pilot study, we report on levels of persistent organohalogenated contaminants (OHCs) in hair of polar bears (Ursus maritimus) from East Greenland sampled between 1999 and 2001. To our knowledge, this is the first study on the validation of polar bear hair as a non-invasive matrix representative of concentrations and profiles in internal organs and blood plasma. Because of low sample weights (13-140 mg), only major bioaccumulative OHCs were detected above the limit of quantification: five polychlorinated biphenyl (PCB) congeners (CB 99, 138, 153, 170 and 180), one polybrominated diphenyl ether (PBDE) congener (BDE 47), oxychlordane, trans-nonachlor and β-hexachlorocyclohexane. The PCB profile in hair was similar to that of internal tissues (i.e. adipose, liver, brain and blood), with CB 153 and 180 as the major congeners in all matrices. A gender difference was found for concentrations in hair relative to concentrations in internal tissues. Females (n = 6) were found to display negative correlations, while males (n = 5) showed positive correlations, although p-values were not found significant. These negative correlations in females may reflect seasonal OHC mobilisation from periphery adipose tissue due to, for example, lactation and fasting. The lack of significance in most correlations may be due to small sample sizes and seasonal variability of concentrations in soft tissues. Further research with larger sample weights and sizes is therefore necessary to draw more definitive conclusions on the usefulness of hair for biomonitoring OHCs in polar bears and other fur mammals.     

Trans-generational and neonatal humoral immune responses in West Greenland sledge dogs (Canis familiaris) exposed to organohalogenated environmental contaminants

Previous investigations in the Arctic have suggested OHC (organohalogen contaminant) induced immune toxic effects on e.g. polar bears (Ursus maritimus). We therefore studied the dietary impact from minke whale blubber (Balaenoptera acutorostrata), rich in polyunsaturated fatty acids and OHCs, on the humoral immunity of 7 captive West Greenland sledge dog (Canis familiaris) bitches and their 4 pups constituting a sentinel model species for polar bears. A control group was composed of 8 bitches and their 5 pups all fed pork (Suis scrofa) fat. The study included serum IgG measurements (bitches and pups) and specific immune responses towards tetanus toxoid (bitches) and diphtheria toxoid (pups) as well as influenza virus (pups). The analyses showed that IgG concentrations were non-significantly lowest in exposed bitches and pups (t-test: all p > 0.05). In addition, significant lower antibody response was detected in exposed pups immunized with influenza virus at age 3 months (t-test: both p < 0.05). No clear group differences were found for tetanus toxoid in bitches and diphtheria toxoid in pups. The results suggest that the humoral immune system of sledge dogs may be suppressed by the dietary blubber composition of OHCs and polyunsaturated fatty acids while a larger follow-up study is recommended in order to investigate this relationship further.     

Differences between Arctic and Atlantic fjord systems on bioaccumulation of persistent organic pollutants in zooplankton from Svalbard

Differences in bioaccumulation of persistent organic pollutants (POPs) between fjords characterized by different water masses were investigated by comparing POP concentrations, patterns and bioaccumulation factors (BAFs) in seven species of zooplankton from Liefdefjorden (Arctic water mass) and Kongsfjorden (Atlantic water mass), Svalbard, Norway. No difference in concentrations and patterns of POPs was observed in seawater and POM; however higher concentrations and BAFs for certain POPs were found in species of zooplankton from Kongsfjorden. The same species were sampled in both fjords and the differences in concentrations of POPs and BAFs were most likely due to fjord specific characteristics, such as ice cover and timing of snow/glacier melt. These confounding factors make it difficult to conclude on water mass (Arctic vs. Atlantic) specific differences and further to extrapolate these results to possible climate change effects on accumulation of POPs in zooplankton. The present study suggests that zooplankton do biomagnify POPs, which is important for understanding contaminant uptake and flux in zooplankton, though consciousness regarding the method of evaluation is important.     

Levels and spatial and temporal trends of contaminants in Greenland biota: an updated review

Knowledge of contaminant levels in Greenland biota has increased substantially in recent years, particularly for persistent organic pollutants. This paper reviews and updates knowledge of spatial and temporal trends of Cd, Hg and organochlorines (PCBs, DDTs, HCHs, HCB and chlordane-related compounds) in Greenland terrestrial, freshwater and marine biota. The most comprehensive studies of spatial trends of Cd and Hg in the terrestrial ecosystem concern lichens, with relatively complete coverage, and caribou (Rangifer tarandus), with coverage mainly in different regions of central West Greenland and Southwest Greenland. The Arctic char (Salvelinus alpinus) is the only freshwater organism for which studies of spatial trends of Hg levels have been completed. Information on spatial trends of Cd and Hg in the marine environment is available from studies of fish, seabirds, ringed seals (Phoca hispida) and polar bears (Ursus maritimus). Geographical patterns of Cd and Hg in Greenland biota were not always consistent among different species or different studies. In landlocked Arctic char the concentrations of Hg decreased from south to north. In marine animals levels of Hg tended to be higher in East Greenland than in West Greenland and Cd levels were highest in biota from Disko Island in central West Greenland. The observed regional differences are difficult to explain but in most cases the causes appear to be natural rather than anthropogenic. Only a few time series covering the last 20 years exist for Cd and Hg. The one time series indicating a temporal change is for ringed seals in Northwest Greenland, which shows an increasing trend of Hg and a decreasing trend of Cd since 1984. Whether the changes reflect anthropogenic inputs, seal behaviour or other environmental factors is unknown. The most significant new insights have concerned organochlorines. In general, levels of these compounds were very low in terrestrial biota compared to marine species. Concentrations in landlocked Arctic char were highest in Southeast Greenland and lowest in Northwest and Northeast Greenland. Marine species from East Greenland had consistently higher levels of SigmaPCB, SigmaDDT and SigmaHCH than marine species from West Greenland. Very few data exist to evaluate temporal changes of organochlorine levels in Greenland biota, and this is the most significant knowledge gap at present. The most pronounced change observed was a decrease of 78% in SigmaPCB levels in polar bears from East Greenland from 1990 to 2000. Levels of SigmaHCH in shorthorn sculpins (Myoxocephalus scorpius) and seals from both central West Greenland and central East Greenland appear to have decreased since 1994. Increasing trends of SigmaDDT from 1994 until now were found in both sexes of seals as well as in male sculpins from central West Greenland.     

Dietary composition in Greenland 2000, plasma fatty acids and persistent organic pollutants

Human exposure to pollution in the Arctic presents a potential future health risk for the local populations. Epidemiological studies in Greenland have shown that human blood levels of several organic contaminants are very high, especially in the North where people depend on local food. In East Greenland (Ittoqqortoormiit (Scoresbysund)) the population shows the highest blood levels of several persistent organic pollutants found in Arctic countries, especially PCB, the levels of which exceed Canadian guideline levels. As in other Arctic countries, the direct source of these contaminants is the diet, and it is, therefore important to monitor the composition of the diet along with other factors which may influence the metabolism and thereby the accumulation of toxic substances. This project is part of the human health program of the ongoing circumpolar 'Arctic Monitoring and Assessment Programme'. Dietary survey results (Semiquantitative Food Frequency questionnaire from 192 men and women from East Greenland and 48 men from Uummannaq West Greenland) were analysed along with other factors (lifestyle and anthropometric factors), blood lipids, fatty acid profiles, and concentrations of persistent organic pollutants (POPs). The dietary survey showed that the contributions of traditional food provided 25-30% of the total energy intake. However, the relative monthly meal intake of seal, whale, polar bear, fish and game, and the composition of imported food, varied between districts. The blood fatty acids (FA), e.g. the n-3/n-6 ratio (Uummannaq 0.70, Ittoqqortoormiit 0.37 Tassiilaq 0.45) showed moderate associations with the overall reported food composition. The n-3 fatty acids were associated with the well-known lowering effect on serum-triglyceride levels. The strongest associations between diet and plasma fatty acids were found for docosapentaenoic acid, C: 22.5.3 which strongly correlated with reported seal, and polar bear intake (P=0.01** and 0.04*, respectively), consistent with the fact that seal and polar bear blubber contain much higher concentrations of C: 22.5.3 than other sea mammals and fish. Seal and polar bear intake, and in particular all the plasma n-3 fatty acids, were significantly correlated with organic contaminant concentrations, (betaHCH, chlordanes, DDTs, Hexachlorobenzene, Mirex, PCBs, and toxaphenes) P<0.01**. CONCLUSIONS: The strongest correlations between POPs and fatty acids were found with C: 22.5.3, strongly indicating seal and polar bear blubber as the main contributors of POPs to the local population.     

Levels and trends of radioactive contaminants in the Greenland environment

Levels of radioactive contaminants in various Greenland environments have been assessed during 1999-2001. The source of 137Cs, 90Sr and (239,240)Pu in terrestrial and fresh water environments is mainly global fallout. In addition, the Chernobyl accident gave a small contribution of 137Cs. Reindeer and lamb contain the largest observed 137Cs concentrations in the terrestrial environment--up to 80 Bq kg(-1) fresh weight have been observed in reindeer. Due to special environmental conditions, 137Cs is transferred to landlocked Arctic char with extremely high efficiency in South Greenland leading to concentrations up to 100 Bq kg(-1) fresh weight. In these cases very long ecological half-lives are seen. Concentrations of 99Tc, 137Cs and 90Sr in seawater and in marine biota decrease in the order North-East Greenland and the coastal East Greenland current > South-West Greenland > Central West Greenland and North-West Greenland > Irmiger Sea-Faroe Islands. The general large-scale oceanic circulation combined with European coastal discharges and previous contamination of the Arctic Ocean causes this. As the same tendency is seen for the persistent organic pollutants (POPs) DDT and PCB in marine biota, it is suggested that long-distance oceanic transport by coastal currents is a significant pathway also for POPs in the Greenland marine environment. The peak 99Tc discharge from Sellafield 1994-1995 has only been slightly visible in the present survey year 2000. The concentrations are expected to increase in the future, especially in East Greenland. The Bylot Sound at the Thule Airbase (Pituffik) in North-West Greenland was contaminated with plutonium and enriched uranium in a weapons accident in 1968. Biological activity has mixed accident plutonium efficiently into the new sediments resulting in continued high surface sediment concentrations three decades after the accident. Transfer of plutonium to benthic biota is low--and lower than observed in the Irish Sea. This is supposed to be caused by the physico-chemical form of the accident plutonium. A recent study indicates that 'hot particles' hold considerably more plutonium than previously anticipated and that the Bylot Sound sediments may account for the major part of the un-recovered plutonium after the accident, i.e. approximately 3 kg.     

Life history as a source of variation for persistent organic pollutant (POP) patterns in a community of common bottlenose dolphins (Tursiops truncatus) resident to Sarasota Bay, FL

As apex predators within coastal ecosystems, bottlenose dolphins (Tursiops truncatus) are prone to accumulate complex mixtures of persistent organic pollutants (POPs). While substantial variations in POP patterns have been previously observed in dolphin populations separated across regional- and fine-scale geographic ranges, less is known regarding the factors influencing contaminant patterns within localized populations. To assess the variation of POP mixtures that occurs among individuals of a population, polychlorinated biphenyl (PCB), organochlorine pesticide (OCP) and polybrominated diphenyl ether (PBDE) concentrations were measured in blubber and milk of bottlenose dolphins resident to Sarasota Bay, FL, and principal components analysis (PCA) was used to explain mixture variations in relation to age, sex and reproductive maturity. PCA demonstrated significant variations in contaminant mixtures within the resident dolphin community. POP patterns in juvenile dolphins resembled patterns in milk, the primary diet source, and were dominated by lower-halogenated PCBs and PBDEs. A significant correlation between principal component 2 (PC2) and age in male dolphins indicated that juvenile contaminant patterns gradually shifted away from the milk-like pattern over time. Metabolically-refractory PCBs significantly increased with age in male dolphins, whereas PCBs subject to cytochrome p450 1A1 metabolism did not, suggesting that changes in male POP patterns likely resulted from the selective accumulation of persistent POP congeners. Changes to POP patterns were gradual for juvenile females, but changed dramatically at reproductive maturity and gradually shifted back towards pre-parturient profiles thereafter. Congener-specific blubber/milk partition coefficients indicated that lower-halogenated POPs were selectively offloaded into milk and changes in adult female contaminant profiles likely resulted from the offloading of these compounds during the first reproductive event and their gradual re-accumulation thereafter. Overall, these results indicate that significant variations in contaminant mixtures can exist within localized populations of bottlenose dolphins, with life history factors such as age and sex driving individual differences.     

Contaminants, diet, plasma fatty acids and smoking in Greenland 1999-2005

OBJECTIVES: The purpose of this study is to monitor and assess human exposure to pollution in the Arctic which presents a potential future health risk for the local populations. Epidemiological studies in Greenland have shown that human blood levels of several organic contaminants are very high, especially in the North where people depend on local food. In East Greenland (Ittoqqortoormiit (Scoresbysund)) the population shows the highest blood levels of several persistent organic pollutants found in Arctic countries, especially PCB, the levels of which exceed Canadian guideline levels. As in other Arctic countries, the predominant source of these contaminants is the local diet. However, other factors such as smoking may influence the metabolism and thereby the accumulation of toxic substances. STUDY DESIGN: This project is part of the human health program of the ongoing circumpolar "Artic Monitoring and Assessment Programme". Lifestyle, anthropometric factors, and dietary survey results covering 500 men and women from 6 Greenlandic districts were analyzed along with other factors blood lipids, fatty acid profiles, heavy metals and concentrations of persistent organic pollutants (POPs). RESULTS: The dietary survey showed that the traditional food on the average provided 20-30% of the total energy intake. However, the relative monthly meal intake of seal, whale, polar bear, fish and game, and the composition of imported food, varied between districts. Seal and polar bear intake, and, in particular all the plasma n-3 fatty acids, were significantly correlated with organic contaminant concentrations, (betaHCH, chlordanes, DDTs, Hexachlorobenzene, Mirex, PCBs, and toxaphenes) p<0.01(). After adjusting for age, district, dietary factors or plasma n-3 fatty acids, smoking was significantly correlated with high levels of all the above mentioned POPs. CONCLUSION: The main predictors of high contaminant levels in Greenland were age, district, male gender, smoking and high plasma n-3/n-6 ratio as a marker of high dietary intake of local marine mammals.     

Persistent organochlorine compounds in fetal and maternal tissues: evaluation of their potential influence on several indicators of fetal growth and health

Some organochlorine compounds, such as polychlorinated biphenyls (PCBs), have a tendency to bioaccumulate in humans and predators at the top of the food chain. We have recently confirmed the transplacental transfer of these compounds and the present study has been designed on the same material with the aim of investigating their potential health effects on newborns from 70 pregnant women, resident in a Northern Italy industrial town. Organochlorine compounds [namely, p,p′-dichlorodiphenyltrichloroethane (p,p′-DDT), p,p′-dichlorodiphenyldichloroethene (p,p′-DDE), hexachlorobenzene (HCB), and PCBs] have been analyzed both in cord and maternal serum, placenta, and maternal subcutaneous adipose tissue by GC-MSD. p,p′-DDT levels in the adipose tissue resulted significantly (p < 0.05) related to birth length. Mothers of neonates born by preterm programmed caesarean delivery showed significantly (p < 0.005 for both) higher serum p,p′-DDE serum concentrations and p,p′-DDT levels in the adipose tissue, as compared to mothers delivering at term.     

Levels and trends of poly- and perfluorinated compounds in the arctic environment

Poly- and perfluorinated organic compounds (PFCs) are ubiquitous in the Arctic environment. Several modeling studies have been conducted in attempt to resolve the dominant transport pathway of PFCs to the arctic—atmospheric transport of precursors versus direct transport via ocean currents. These studies are generally limited by their focus on perfluorooctanoate (PFOA) fluxes to arctic seawater and thus far have only used fluorotelomer alcohols (FTOHs) and sulfonamide alcohols as inputs for volatile precursors. There have been many monitoring studies from the North American and European Arctic, however, almost nothing is known about PFC levels from the Russian Arctic. In general, there are very few measurements of PFCs from the abiotic environment. Atmospheric measurements show the widespread occurrence of PFC precursors, FTOHs and perfluorinated sulfonamide alcohols. Further, PFCAs and PFSAs have been detected on atmospheric particles. The detection of PFCAs and PFSAs in snow deposition is consistent with the volatile precursor transport hypothesis. There are very limited measurements of PFCs in seawater. PFOA is generally detected in the greatest concentrations. Additional seawater measurements are needed to validate existing model predications. The bulk of the monitoring efforts in biological samples have focused on the perfluorinated carboxylates (PFCAs) and sulfonates (PFSAs), although there are very few measurements of PFC precursors. The marine food web has been well studied, particularly the top predators. In contrast, freshwater and terrestrial ecosystems have been poorly studied. Studies show that in wildlife perfluorooctane sulfonate (PFOS) is generally measured in the highest concentration, followed by either perfluorononanoate (PFNA) or perfluoroundecanoate (PFUnA). However, some whale species show relatively high levels of perfluorooctane sulfonamide (PFOSA) and seabirds are typically characterized by high proportions of the C₁₁-C₁₅ PFCAs. PFOA is generally infrequently detected and is present in low concentrations in arctic biota. Food web studies show high bioaccumulation in the upper trophic-level animals, although the mechanism of PFC biomagnification is not understood. Spatial trend studies show some differences between populations, although there are inconsistencies between PFC trends. The majority of temporal trend studies are from the Northern American Arctic and Greenland. Studies show generally increasing levels of PFCs from the 1970s, although some studies from the Canadian Arctic show recent declines in PFOS levels. In contrast, ringed seals and polar bears from Greenland continue to show increasing PFOS concentrations. The inconsistent temporal trends between regions may be representative of differences in emissions from source regions.     

Combining data sets of organochlorines (OCs) in human plasma for the Russian Arctic

As part of AMAP's human circumpolar study of POPs, an international effort was initiated to extend coverage to communities across the Russian Arctic. Two additional laboratories were invited to join the analytical component of this effort, resulting in four participating analytical centres. Although quality assurance measures were put in place, and the level of performance of the laboratories was generally acceptable, deficiencies in the analytical protocols used were recognized subsequent to the collection and analyses of the plasma specimens. The current paper describes the criteria employed to critically appraise the four data bases and guide their integration into a single data set. Summary statistics are presented for plasma concentrations of major PCBs, p,p′-DDE, p,p′-DDT, β-HCH, and HCB for communities/regions across the arctic/subarctic Russian continent, and for one community located in the Aral Sea area of Uzbekistan (a control group). Highly exposed people were identified in the coastal communities of Chukotka, which appears mainly related to marine mammal intake, but recent pesticide use is also suspected. Other communities with intermediate levels of PCBs had relatively elevated β-HCH, p,p′-DDT and HCB concentrations and low DDE/DDT ratios (<10), suggesting recent pesticide use.     

Disruptive effects of persistent organohalogen contaminants on thyroid function in white whales (Delphinapterus leucas) from Svalbard

We analysed levels of 56 organohalogen contaminants (OHCs) including brominated flame retardants, polychlorinated biphenyls (PCBs), and organochlorine pesticides in the blubber of white (beluga) whales (Delphinapterus leucas) from Svalbard, Norway (N = 12; 6 adults [5 males and 1 female] and 6 subadults [4 males and 2 females]) collected in 1996-2001. We also measured circulating levels of thyroid hormones (THs) and thyroid stimulating hormone (TSH) in the whales. The results confirm that OHC levels in these white whales are among the highest levels recorded in wildlife from Svalbard, and at the high end of the range when compared to white whales from the North American Arctic. A projection to latent structure (PLS) model (subadults and adult males grouped together) revealed that known or suspected thyroid disruptive contaminants (polybrominated diphenylether [PBDE]-28, -47, -99, -100, and -154, hexachlorobenzene [HCB], and PCB-105) were negatively correlated with circulating levels of total thyroxin (TT4), free T4 (FT4) and free triiodothyronine (FT3). Most of these negative relationships were also confirmed using partial correlations controlling for length (and thus age) of the whales. The positive correlations of TT4, FT4 and FT3 with hexabromocyclododecane (HBCD), α-hexachlorocyclohexane (α-HCH), chlorinated bornanes CHB-40 and CHB-62 revealed by the PLS model were not confirmed by partial correlations. TH levels in the present study appeared to be somewhat lower than levels measured in beluga whales from the Canadian Arctic. However, we were not able to determine if this was caused by different levels of OHCs, or differences in biological factors (e.g. age, sex, moulting status, and season) and analytical methods between the studies. Although the sample sizes were low and statistical models cannot depict the biological cause-effect relationships, this study suggests negative influences of specific OHCs, particularly PBDEs, on thyroid hormone levels in white whales. The impact this might have on individual and population health is unknown.     

In vitro steroidogenic effects of mixtures of persistent organic pollutants (POPs) extracted from burbot (Lota lota) caught in two Norwegian lakes

This study investigated the effects of two mixtures of persistent organic pollutants (POPs) on steroidogenesis in the H295R cell line. The two mixtures were obtained from the livers of burbot (Lota lota) caught in two Norwegian lakes (Mjøsa and Losna) with different contaminant profiles. Steroid hormone levels in the cell culture medium and mRNA levels of 16 genes involved in steroidogenesis were investigated. The crude Lake Mjøsa extract had to be diluted ten times more than the Lake Losna extract in order to prevent cytotoxicity. The ten times diluted Lake Mjøsa mixture had higher levels of DDT and derivates (∑ DDTs, 1.7 times) and brominated flame retardants (∑ BDEs and HBCD, 15-25 times) than the Lake Losna mixture, which, on the other hand, had higher concentrations of ∑ PCBs (1.5 times higher) and also of HCB, ∑ HCH isomers and ∑ chlordane isomers (5-20 times higher).In the cell culture media, only cortisol levels were increased at the highest exposure concentration to the Lake Mjøsa mixture, while both cortisol and estradiol levels were increased following exposure to the two highest Lake Losna mixture exposure concentrations. Testosterone levels decreased only at the highest exposure concentration of the Lake Losna mixture. Multivariate models suggested that ∑ PCBs, and to a lesser extent ∑ DDTs, were responsible for the cortisol responses, while estradiol and testosterone alterations were best explained by HCB and ∑ PCBs, respectively. Exposure to the mixtures generally increased mRNA levels, with smaller effects exerted by the Lake Mjøsa mixture than the Lake Losna mixture. It was concluded that both mixtures affected steroidogenesis in the H295R cells. Small differences in mixture composition, rather than the high content of brominated flame retardants in the Lake Mjøsa mixture, were suggested to be the most probable reason for the apparent differences in potencies of the two mixtures.     

Brominated flame retardants in the Arctic environment — trends and new candidates

Polybrominated diphenyl ethers (PBDEs) containing two to 10 bromines are ubiquitous in the Arctic, in both abiotic and biotic samples. Hexabromocyclododecane (HBCD) is also ubiquitous in the Arctic, with the γ-HBCD isomer predominating in air, the α-HBCD isomer predominating in biota and similar concentrations of α-, β- and γ-HBCD found in marine sediments. Other brominated flame retardants (BFRs) found in some Arctic samples are polybrominated biphenyls (PBBs), tetrabromobisphenol A (TBBPA), 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), hexabromobenzene (HxBBz), pentabromoethylbenzene (PBEB), pentabromotoluene (PBT), and 1,2-dibromo-4-(1,2-dibromoethyl)cyclohexane (TBECH). Temporal trends of tetra- to heptaBDEs and HBCD show increasing concentrations or a tendency to levelling off depending on the matrix (air, sediment, biota) and location, but no uniform picture for the Arctic emerges. BDE-209 concentrations are increasing in air. PBDEs and HBCD spatial trends in seabirds and marine mammals are similar to those seen previously for polychlorinated biphenyls (PCBs), with highest concentrations found in organisms from East Greenland and Svalbard. These trends indicate western Europe and eastern North America as important source regions of these compounds via long range atmospheric transport and ocean currents. Latitudinal trends showed lower concentrations and fluxes of PBDEs at higher latitudes. The tetra-hexaBDEs and α-HBCD biomagnify in Arctic food webs. Results for BDE-209 are more conflicting, showing either only low or no biomagnification potential. PBDE and HBCD concentrations are lower in terrestrial organisms and higher in marine top predators such as some killer whale populations in Alaska and glaucous gulls from the Barents Sea area. Higher concentrations are seen near populated areas indicating local sources. Findings of BTBPE, HxBBz, PBEB, PBT and TBECH in seabirds and/or marine mammals indicate that these compounds reach the Arctic, most probably by long range atmospheric transport and accumulate in higher trophic level organisms and that increasing use as PBDE replacements will lead to increasing concentrations.     

Concentrations and determinants of organochlorine levels among pregnant women in Eastern Spain

Persistent organic pollutants (POPs) comprise a large variety of toxic substances with ample distribution. While exposure to these toxins occurs mainly through diet, maternal POP levels may be influenced by certain sociodemographic, environmental, or lifestyle factors. This is important given that these substances may have adverse effects on fetal development. The aim of this study is to examine the sociodemographic, environmental, lifestyle, and dietary determinants of the levels of hexachlorobenzene (HCB), b-hexachlorocyclohexane (b-HCH), 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (4,4′-DDT), 1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene (4,4′-DDE), and polychlorinated biphenyls (PCB congeners 118, 138, 153, 180) measured in the blood of pregnant women participating in a mother-child cohort study conducted in Valencia (Spain).The study population consisted of 541 pregnant women who formed part of the INMA (Childhood and the Environment) cohort (2004-2006). POP levels were determined in blood taken during the 12th week of pregnancy with the aid of gas chromatography with electron capture detection. Sociodemographic, environmental, and dietary information was obtained from a questionnaire. Multivariate Tobit regression models were constructed in order to assess the association between POP levels and selected covariates.The results showed that all the women had detectable levels of at least one of these compounds while in 43% of the subjects, all eight compounds were detected. The compounds found in the greatest number of women were 4,4′-DDE (100%) and PCBs 153 and 180 (95%). The most important determinants of high POP levels were the mother's age, country of origin, increased body mass index, and number of weeks of breastfeeding after previous pregnancies. With regard to diet, 4,4′-DDT and 4,4′-DDE levels increased with the intake of meat, fruit, and cereal. PCB 153 levels increased with the intake of seafood. The levels of HCB, b-HCH, 4,4′-DDT, and 4,4′-DDE observed in this study were slightly higher than in other studies, whereas the PCB levels were similar.     

Maternal levels of organochlorines in two communities in southern Vietnam

Some pesticides and PCBs continue to be reported as environmental problems in some areas of Vietnam. In 2005, a study among delivering women took place in two communities in south-central Vietnam (Khanh Hoa Province), namely the coastal city of Nha Trang and the rural district of Dien Khanh located about 10 km inland. The main findings in plasma (n = 189) were relatively high mean concentrations of p,p′-DDE (12.2 µg/l in Nha Trang and 11.4 µg/l in Dien Khanh) and p,p′-DDT (1.2 µg/l in Nha Trang and 1.1 µg/l in Dien Khanh) with no significant community differences. The ratio of p,p′-DDE/p,p′-DDT (11.5 in Nha Trang/12.7 in Dien Khanh) suggests, as in other Vietnamese OCs studies, a relatively recent use of this pesticide. Mean concentrations of PCB 153 (0.15 µg/l in Nha Trang and 0.10 µg/l in Dien Khanh) and other congeners were low in both communities. Age and parity (all compounds), as well as community of residence for PCB 153, were the most important predictors of plasma OCs concentrations.     

Contaminants in Svalbard polar bear samples archived since 1967 and possible population level effects

Blood plasma samples were collected in 1967 from 32 polar bears (Ursus maritimus) in eastern Svalbard. These samples were stored frozen until 2001 and then analyzed for 33 polychlorinated biphenyls (PCB), two toxaphene congeners, DDTs, chlordanes (CHL), hexachlorobenzene, hexachlorocyclohexanes (HCHs), and polybrominated flame retardants (biphenyls and diphenyl ethers). The 1967 pollutant levels were compared with values from 1993 to 1994 for adult females and adult males to obtain insights into the historical development of pollution in the Norwegian Arctic. Differences in the OC levels measured between 1967 and 1993-1994 ranged from a decrease (PCB 187 and p,p-DDE) to unchanged in both sexes (PCBs 105, 118, 209, and HCH) to an increase in females (PCBs 99, 128, and CHL), to increases in both sexes (PCBs 138, 153, 156, 157, 170, 180, 194, and 206). The maximum change was a nine-fold increase in PCB 157 in adult females. Changes from 1967 to 1993-1994 in contaminant pattern expressed relative to PCB 153 could be explained by a combination of selective metabolism and accumulation of organochlorines in polar bears and temporal changes in the contaminant mixture being transported to the Arctic. Harvest of polar bears in Svalbard ended in 1973 and it appears that most pollutant levels were increasing at the same time that the population was expected to recover from over-harvest. The mean age of adult females in the Svalbard population was similar to other populations where pollution levels are lower but harvest is intense. Females with cubs-of-the-year > or =16 years old are uncommon in the population for unknown reasons. The impacts of contaminants on the Svalbard polar bear population are inconclusive but there are suggestions of contaminant-related population level effects that could have resulted from reproductive impairment of females, lower survival rates of cubs, or increased mortality of reproductive females.     

Influence of sex, maturity and reproduction on PCB and p,p′DDE concentrations and repartitions in the European hake (Merluccius merluccius, L.) from the Gulf of Lions (N.W. Mediterranean)

The main objective of this work was to establish the influence of sex, maturity and reproduction on the contamination of the demersal fish Merluccius merluccius by organochlorine compounds. Polychlorinated biphenyls (PCBs) and p,p′DDE were quantified in muscle, liver and gonads of female and male hakes collected in the Gulf of Lions in 2004 and 2005. Observed levels appeared higher than the population of the Bay of Biscay and lower than the population of the Thyrrenian Sea. Contaminant fingerprints were roughly constant whatever the studied organ and the hake biological condition. Concentrations varied significantly according to the sex and maturity of hakes. Mature specimens were more contaminated than immature, and males presented higher levels than females. This sex effect can be linked to a lower growth rate of males, and a contaminant elimination during female spawning. Gonadal contamination depends on the importance of lipid content and increases with the maturation degree. Although the main organ of energy and PCB storage is the liver, muscle appears as the main contributor to the gonad contamination.     

Environmental contaminants and human health in the Canadian Arctic

The third Canadian Arctic Human Health Assessment conducted under the Canadian Northern Contaminants Program (NCP), in association with the circumpolar Arctic Monitoring and Assessment Programme (AMAP), addresses concerns about possible adverse health effects in individuals exposed to environmental contaminants through a diet containing country foods. The objectives here are to: 1) provide data on changes in human contaminant concentrations and exposure among Canadian Arctic peoples; 2) identify new contaminants of concern; 3) discuss possible health effects; 4) outline risk communication about contaminants in country food; and 5) identify knowledge gaps for future contaminant research and monitoring. The nutritional and cultural benefits of country foods are substantial; however, some dietary studies suggest declines in the amount of country foods being consumed. Significant declines were found for most contaminants in maternal blood over the last 10 years within all three Arctic regions studied. Inuit continue to have the highest levels of almost all persistent organic pollutants (POPs) and metals among the ethnic groups studied. A greater proportion of people in the East exceed Health Canada's guidelines for PCBs and mercury, although the proportion of mothers exceeding these guidelines has decreased since the previous assessment. Further monitoring and research are required to assess trends and health effects of emerging contaminants. Infant development studies have shown possible subtle effects of prenatal exposure to heavy metals and some POPs on immune system function and neurodevelopment. New data suggest important beneficial effects on brain development for Inuit infants from some country food nutrients. The most successful risk communication processes balance the risks and benefits of a diet of country food through input from a variety of regional experts and the community, to incorporate the many socio-cultural and economic factors to arrive at a risk management decision that will be the most beneficial in Arctic communities.     

Atmospheric monitoring of organic pollutants in the Arctic under the Arctic Monitoring and Assessment Programme (AMAP): 1993-2006

Continuous and comparable atmospheric monitoring programs to study the transport and occurrence of persistent organic pollutants (POPs) in the atmosphere of remote regions is essential to better understand the global movement of these chemicals and to evaluate the effectiveness of international control measures. Key results from four main Arctic research stations, Alert (Canada), Pallas (Finland), Storhofdi (Iceland) and Zeppelin (Svalbard/Norway), where long-term monitoring have been carried out since the early 1990s, are summarized. We have also included a discussion of main results from various Arctic satellite stations in Canada, Russia, US (Alaska) and Greenland which have been operational for shorter time periods. Using the Digital Filtration temporal trend development technique, it was found that while some POPs showed more or less consistent declines during the 1990s, this reduction is less apparent in recent years at some sites. In contrast, polybrominated diphenyl ethers (PBDEs) were still found to be increasing by 2005 at Alert with doubling times of 3.5 years in the case of deca-BDE. Levels and patterns of most POPs in Arctic air are also showing spatial variability, which is typically explained by differences in proximity to suspected key source regions and long-range atmospheric transport potentials. Furthermore, increase in worldwide usage of certain pesticides, e.g. chlorothalonil and quintozene, which are contaminated with hexachlorobenzene (HCB), may result in an increase in Arctic air concentration of HCB. The results combined also indicate that both temporal and spatial patterns of POPs in Arctic air may be affected by various processes driven by climate change, such as reduced ice cover, increasing seawater temperatures and an increase in biomass burning in boreal regions as exemplified by the data from the Zeppelin and Alert stations. Further research and continued air monitoring are needed to better understand these processes and its future impact on the Arctic environment.