Transplacental Transfer of Polychlorinated Biphenyls, Polybrominated Diphenylethers, and Organochlorine Pesticides in Ringed Seals (Pusa hispida).

The transplacental transfer of persistent organic pollutants in marine mammals takes place at a formative developmental period, thereby exposing the fetus to endocrine-disrupting compounds. We evaluated the transplacental transfer of polychlorinated biphenyls (PCBs), polybrominated diphenylethers (PBDEs), and organochlorine pesticides (OCPs) in five pregnant ringed seals in Northern Labrador, Canada. PCBs, PBDEs, and OCPs were transferred from the mother to the fetus with average concentrations in the fetuses ranging from 0.3 ng/g lipid weight (lw) of mirex to 94 ng/g lw of PCBs. The average percent transferred to the blubber in the fetus was very low with <0.02 % for each of the compounds studied. Based on relationships observed, transfer for full-term fetuses is estimated to range from 0.03 to 0.27 %. Log K(ow) explained the transfer of PCBs (r (2) = 0.67, p < 0.001) and OCPs (r (2) = 0.62, p < 0.001) with those PCB congeners and OCP compounds having a log K(ow) of <6.0 and 4.6, respectively, because they are preferentially transferred to the fetus. Adult females transferred a contaminant mixture to their fetuses, which correlated with estimated fetal age (p < 0.001; r (2) = 0.697), with younger fetuses showing a greater proportion of compounds with low K(ow) compared with later-term fetuses. The implications for the prenatal exposure to these developmental toxicants remains unknown because current toxicity thresholds in marine mammals have only been derived from juveniles or adults.

Determination of arsenic species in edible periwinkles (Littorina littorea) by HPLC-ICPMS and XAS along a contamination gradient.

Arsenic is naturally found in the tissues of marine animals, usually as the non-toxic arsenical arsenobetaine, but exposure to elevated arsenic concentrations in the environment may alter the arsenic species distribution within tissues of the organism. This study examined the arsenic species in the tissues of the marine periwinkle (Littorina littorea) along an arsenic concentration gradient in the sediment. The arsenicals in L. littorea were examined using the complementary analytical methods high performance liquid chromatography coupled with inductively coupled plasma mass spectrometry (HPLC-ICPMS) and X-ray absorption spectroscopy (XAS). Total arsenic concentrations in the periwinkle tissues ranged from 56 to 840 mg·kg(-1) dry weight (equivalent to 13 to 190 mg·kg(-1) wet weight). Inorganic arsenicals were found to be positively correlated with total arsenic concentrations (R(2)=0.993) and reached 600 mg·kg(-1) dry weight, the highest reported to date in marine organisms. These high inorganic arsenic concentrations within this low trophic organism pose a potential toxicological risk to higher trophic consumers.

Arsenobetaine formation in plankton: a review of studies at the base of the aquatic food chain.

Arsenobetaine is one of the major organoarsenic compounds found in aquatic organisms, including seafood and fish meant for human consumption. It has been widely studied over the last 50 years because of its non-toxic properties, and its origin is postulated to be at bottom of the aquatic food chains. The present review focuses on arsenobetaine formation in marine and freshwater plankton, comparing the arsenic compounds found in the different plankton organisms, and the methods used to assess arsenic speciation. The main findings indicate that in the marine environment, phytoplankton and micro-algae contain arsenosugars, with the first traces of arsenobetaine appearing in herbivorous zooplankton, and becoming a major arsenic compound in carnivorous zooplankton. Freshwater plankton contains less arsenobetaine than their marine relatives, with arsenosugars dominating. The possible role and formation pathways of arsenobetaine in plankton organisms are reviewed and the literature suggests that arsenobetaine in zooplankton comes from the degradation of ingested arsenosugars, and is selectively accumulated by the organism to serve as osmolyte. Several arsenic compounds such as arsenocholine, dimethylarsinoylacetate or dimethylarsinoylethanol that are intermediates of this pathway have been detected in plankton. The gaps in research on arsenobetaine in aquatic environments are also addressed: primarily most of the conclusions are drawn on culture-based experiments, and few data are present from the natural environment, especially for freshwater ecosystems. Moreover, more data on arsenic in different zooplankton species would be helpful to confirm the trends observed between herbivorous and carnivorous organisms.

Arsenic speciation in blue mussels (Mytilus edulis) along a highly contaminated arsenic gradient.

Arsenic is naturally present in marine ecosystems, and these can become contaminated from mining activities, which may be of toxicological concern to organisms that bioaccumulate the metalloid into their tissues. The toxic properties of arsenic are dependent on the chemical form in which it is found (e.g., toxic inorganic arsenicals vs nontoxic arsenobetaine), and two analytical techniques, high performance liquid chromatography coupled with inductively coupled plasma mass spectrometry (HPLC-ICP-MS) and X-ray absorption spectroscopy (XAS), were used in the present study to examine the arsenic species distribution in blue mussels (Mytilus edulis) obtained from an area where there is a strong arsenic concentration gradient as a consequence of mining impacted sediments. A strong positive correlation was observed between the concentration of inorganic arsenic species (arsenic compounds with no As-C bonds) and total arsenic concentrations present in M. edulis tissues (R(2) = 0.983), which could result in significant toxicological consequences to the mussels and higher trophic consumers. However, concentrations of organoarsenicals, dominated by arsenobetaine, remained relatively constant regardless of the increasing As concentration in M. edulis tissue (R(2) = 0.307). XANES bulk analysis and XAS two-dimensional mapping of wet M. edulis tissue revealed the presence of predominantly arsenic-sulfur compounds. The XAS mapping revealed that the As(III)-S and/or As(III) compounds were concentrated in the digestive gland. However, arsenobetaine was found in small and similar concentrations in the digestive gland as well as the surrounding tissue suggesting arsenobetaine may being used in all of the mussel's cells in a physiological function such as an intracellular osmolyte.

Arsenic species extraction of biological marine samples (Periwinkles, Littorina littorea) from a highly contaminated site.

Arsenic is ubiquitous in the tissues of marine organisms and in uncontaminated environments it is dominantly present as the highly soluble and easily extractable non-toxic arsenical, arsenobetaine. However in contaminated environments, higher proportions of inorganic arsenic, which is much less soluble, are accumulated into the tissues of marine organisms, resulting in lower extraction efficiencies (defined as the percent extracted arsenic of the total arsenic). This study carried out a comparative analysis between three different two-step arsenic extraction methods based on Foster et al. [27] from highly contaminated tissue of the marine periwinkle, Littorina littorea. The first extraction step used 100% water, 1:1 methanol-water, or a 9:1 methanol-water as the extraction solvent and the second step consisted of a gently heated dilute nitric acid extraction. The optimized two step extraction method was 1:1 methanol-water extraction followed by a 2% HNO(3) extraction, based on maximum amounts of extracted species, including organoarsenic species.

Validation of diabetes case definitions using administrative claims data.

AIMS: Our aim was to validate three diabetes case definitions for children and adolescents aged <20 years in Canada using administrative and clinical data in the province of British Columbia. METHODS: We identified potential cases of diabetes from physician claims, hospitalizations and prescription drug records between 1992/1993 and 2007/2008 using the three different case definitions, which included a national standard as well as two regionally developed case definitions. Each case definition used a different combination of administrative data; however, only one definition used prescription drug records. The sensitivity of each definition was calculated against the 'gold standard' of diagnosed cases recorded in British Columbia's Children's Hospital Endocrinology and Diabetes Unit clinical database. RESULTS: During this time period, 2611 patients were seen at the British Columbia's Children's Hospital. The sensitivities (95% CIs) of the national and two regional case definitions were 0.95 (0.941-0.958), 0.97 (0.964-0.977) and 0.82 (0.800-0.830), respectively. CONCLUSIONS: Our results highlight the benefit of regional case definitions that exploit the availability of different data sources, but also support that a nationally derived definition is sensitive among children and adolescents.

Long-term efficacy and safety of combined prolonged-release oxycodone and naloxone in the management of non-cancer chronic pain.

OBJECTIVE: The aim of this study was to assess safety and efficacy of fixed combination oxycodone prolonged release (PR)/naloxone PR in terms of both analgesia and improving opioid-induced bowel dysfunction (OIBD) and associated symptoms, such as opioid-induced constipation (OIC), in adults with chronic non-cancer pain. STUDY DESIGN: These were open-label extension studies in which patients who had previously completed a 12-week, double-blind study received oxycodone PR/naloxone PR for up to 52 weeks. The analgesia study assessed pain using the modified Brief Pain Inventory-Short Form (BPI-SF). The bowel function study assessed improvements in constipation using the Bowel Function Index (BFI). RESULTS: At open-label baseline in the analgesia study (n = 379), mean score [+/- standard deviation (SD)] for the BPI-SF item 'average pain over the last 24 h' was 3.9 +/- 1.52, and this remained low at 6 months (3.7 +/- 1.59) and 12 months (3.8 +/- 1.72). Mean scores for BPI-SF item 'sleep interference', and the BPI-SF 'pain' and 'interference with activities' subscales also remained low throughout the 52-week study. In the bowel function study (n = 258), mean BFI score (+/- SD) decreased from 35.6 +/- 27.74 at the start of the extension study to 20.6 +/- 24.01 after 12 months of treatment with oxycodone PR/naloxone PR. Pain scores also remained low and stable during this study. Adverse events in both extension phases were consistent with those associated with opioid therapy; no additional safety concerns were observed. CONCLUSION: Results from these two open-label extension studies demonstrate the long-term efficacy and tolerability of fixed combination oxycodone PR/naloxone PR in the treatment of chronic pain. Patients experienced clinically relevant improvements in OIBD while receiving effective analgesic therapy.

Combined prolonged-release oxycodone and naloxone improves bowel function in patients receiving opioids for moderate-to-severe non-malignant chronic pain: a randomised controlled trial.

BACKGROUND: This randomised, double-blind, double-dummy, parallel-group multicentre study assessed the impact of a total daily dose of 60-80 mg oral oxycodone prolonged-release (PR)/naloxone PR (OXN PR) as fixed-ratio combination for patients with opioid-induced constipation (OIC) having moderate-to-severe, non-malignant pain. METHODS: During pre-randomisation patients receiving opioids for moderate-to-severe non-malignant pain were converted to oxycodone PR (OXY PR) and titrated to an effective analgesic dose. During randomisation 265 patients on a stable OXY PR dose (60-80 mg/day) and with OIC were included in the full analysis population to receive OXN PR or OXY PR alone. Primary outcome was improvement in symptoms of constipation as measured by the Bowel Function Index (BFI). Secondary/exploratory outcomes examined analgesic efficacy and other bowel function parameters. RESULTS: After 4 weeks of treatment, patients receiving OXN PR showed a significant improvement in bowel function compared with those in the OXY PR group (-14.9; 95% CI: -17.9, -11.9; p<0.0001) as measured by BFI which was seen after only 1 week of treatment continuing to the end of the study. After 4 weeks of treatment, patients receiving OXN PR had a median number of 3.0 complete spontaneous bowel movements (CSBM) per week compared with only 1.0 for OXY PR alone. Laxative intake was lower in the OXN PR than the OXY PR group. Furthermore, improvements in bowel function were achieved without loss of analgesic efficacy; pain intensity scores were comparable between the groups and consistent for duration of the study. Most frequently reported adverse events were consistent with those reported for opioid analgesics; no new or unexpected adverse reactions attributable to OXN PR used in higher doses were observed. CONCLUSION: This study shows that the fixed-ratio combination of OXN PR is superior to OXY PR alone in terms of bowel function, while providing effective equivalent analgesia.

Fixed-ratio combination oxycodone/naloxone compared with oxycodone alone for the relief of opioid-induced constipation in moderate-to-severe noncancer pain.

OBJECTIVE: Opioid therapy is frequently associated with treatment-limiting constipation. Naloxone is an opioid antagonist with low oral systemic bioavailability. This Phase III clinical trial assessed the safety and efficacy of an oral fixed-ratio combination of oxycodone prolonged-release (PR) and naloxone PR compared with oxycodone PR in relieving opioid-induced constipation. STUDY DESIGN: This double-blind, multicenter trial was conducted in specialist and primary care centers in four European countries in an out-patients setting. The study included 322 adult patients with moderate-to-severe, noncancer pain requiring opioid therapy in a range of >or=20 mg/day and

Patient assessment of a novel therapeutic approach for the treatment of severe, chronic pain.

BACKGROUND AND OBJECTIVES: Opioid-induced constipation can have a major negative impact on patients' quality of life. This randomised clinical trial evaluated patient assessment of the efficacy and tolerability of oral prolonged-release (PR) oxycodone when co-administered with oral naloxone PR. METHODS: Two hundred and two patients with chronic cancer- or non-cancer-related pain undergoing stable oxycodone PR therapy (40, 60 or 80 mg/day) were randomised to one of four intervention groups: 10, 20 or 40 mg/day naloxone PR or placebo. Following a 4-week maintenance phase, patients were followed-up for 2 weeks in which time they received oxycodone PR only. At the end of the maintenance phase, patients and investigators were asked to assess treatment efficacy and tolerability, as well as preference for the titration or maintenance phase. RESULTS: Patient and investigator global assessment of efficacy and tolerability improved with increasing naloxone dose. Efficacy was ranked as 'good' or 'very good' by 50.0%, 67.4% and 72.5% of patients in the 10, 20 and 40 mg naloxone PR dose groups, respectively, compared with 43.5% of patients in the placebo group. Patient assessment of tolerability was similar between treatment groups and placebo, being ranked as 'good' or 'very good' by 83.3%, 79.1% and 82.5% of patients in the 10, 20 and 40 mg/day naloxone PR dose groups, respectively, compared with 71.7% of patients in the placebo group. The maintenance treatment phase was preferred by patients in the naloxone groups. A 2 : 1 dose ratio of oxycodone to naloxone was also assessed. Efficacy was ranked as 'good' or 'very good' by 70.4% of patients treated with the 2 : 1 dose ratio compared with 43.5% of patients receiving placebo. Tolerability of the 2 : 1 dose ratio was ranked as being 'good' or 'very good' by 81.5% of patients compared with 71.1% for the placebo group and patients preferred the maintenance phase. CONCLUSIONS: The co-administration of oral naloxone PR with oxycodone PR improves patient assessment of analgesic opioid therapy for severe chronic pain, in terms of both efficacy and tolerability.

Anti-inflammatory properties of a liposomal hydrogel with povidone-iodine (Repithel) for wound healing in vitro.

A liposomal hydrogel with 3% povidone-iodine (PVP-ILH, Repithel) has shown clinical benefit in settings where inflammation and/or reactive oxygen species are thought to impede wound healing (e.g., burns, chronic wounds and in smokers). This in vitro study investigated whether PVP-ILH is able to reduce inflammatory events responsible for the impairment of the wound healing process in such patients. Therefore, the following assays were conducted with PVP-ILH (and derived control hydrogels to identify the component responsible for the effect): inhibition of reactive oxygen species production by human polymorphonuclear neutrophils (PMNs) and in a cell-free system, oxygen consumption assay of PMNs (prior to oxidative burst), inhibition of human complement (limiting the generation of complement factors), mast cell degranulation, nitric oxide production by murine macrophages and TNF-alpha production by human monocytes/macrophages. Where toxicity could cause cell inhibition, cell viability was assessed. PVP-ILH and its components interacted in our series of bioassays at various stages in the inflammation cascade. Scavenging of superoxide anions was the most pronounced effect. Furthermore, povidone-iodine inhibited PMN production of reactive oxygen species (inhibition of oxygen consumption) and a mast cell inhibitory (stabilising) activity was observed. Based on these results, the clinically observed, beneficial wound healing effects of PVP-ILH may also be attributed to an impediment of inflammatory activity, mainly by iodine's free radical scavenging. Controlling oxidative stress in the wound may be of great importance, especially since further reactions as, e.g., the formation of peroxynitrite from NO and ROS are prevented.

[Local therapy of grade IIa burns: efficacy and tolerability of a new hydrosome wound gel for the local treatment of grade IIa burns as compared with silver sulfadiazine ointment]. / Lokale Behandlung von Grad-IIa-Verbrennungen : Wirksamkeit und Verträglichkeit eines neuartigen hydrosomalen Wundgels im Vergleich zu Silbersulfadiazin-Creme.

BACKGROUND: A new hydrosome wound gel is based on a new mechanism of action. It contains hydrosomes that penetrate to the wound bed and supply the wound with phospholipids, which are identical to membrane phospholipids of human cells. In this manner it supports the proliferative processes during wound healing. PATIENTS AND METHODS: In a randomized, controlled, intraindividual comparative study of 47 patients with grade IIa burns, the hydrosome wound gel was tested against silver sulfadiazine cream. Digital pictures of the burn wounds were taken daily, and the wounds were analyzed in terms of their reepithelization rate. RESULTS: Wounds receiving the hydrosome wound gel healed 1.5-2 days faster than wounds treated with sulfadiazine cream (9.9+/-4.5 days vs. 11.3+/-4.9 days, p=0.015). In 66% of the patients, faster epithelization was observed with the hydrosome wound gel treatment. The hydrosome gel guaranteed secure prophylaxis against infection, and it was well tolerated and easy to apply. CONCLUSION: In this study, the treatment of grade IIa burn wounds with hydrosome wound gel led to faster wound closure compared with treatment with sulfadiazine cream. Therefore, hydrosome gel represents a good alternative to sulfadiazine cream.

Arsenic bioaccessibility and speciation in clams and seaweed from a contaminated marine environment.

The bioaccessible concentration and speciation of arsenic (soluble in a gastrointestinal medium and available for absorption into the bloodstream) were determined in softshell clams (Mya arenaria), harvested by local residents until 2005, and in seaweed (Fucus sp.) from an arsenic-contaminated marine site in Seal Harbour, Nova Scotia, Canada. Bioaccessibility extractions to simulate the human gastrointestinal environment (pH 1.5 and glycine for 1h followed by pancreatin, bile extract and pH adjustment to 7 for an additional 4h) and speciation of arsenic in extracts (HPLC-HG-AAS to target inorganic arsenic species) and whole samples (XANES) were carried out. Total arsenic for the clams from the contaminated area ranged from 218 to 228 ppm wet weight, with a bioaccessible fraction of 34-46%, and the major bioaccessible species of arsenic were inorganic. The seaweed from the contaminated area contained 27-43 ppm wet weight total arsenic, with the bioaccessible fraction ranging from 63% to 81%, and inorganic arsenic was also predominant. The predominantly inorganic nature of arsenic in the whole samples was confirmed by XANES. In concurrence with the closure of the area for clam harvesting, the clams and seaweed from Seal Harbour should probably not be used for human consumption.

A clinical study on the tolerability of a liposomal povidone-iodine nasal spray: implications for further development.

PURPOSE OF STUDY: This phase I study assessed tolerability and local effect of a liposome dispersion with povidone-iodine (polyvinylpyrrolidone-iodine, PVP-I) as nasal spray. PROCEDURES: Three groups received liposomal dispersion with PVP-I (2.2, 4.4 and 0% as control) in single and repeated use (3 days, three times a day). A set of functional and cytological tests as well as safety assessments were performed. RESULTS: No safety-relevant finding or serious adverse events were reported, no evidence for cyto- nor genotoxicity obtained. No clinically relevant changes in mucosa appearance, nor in olfactory sense, nor in ciliary activity (sensitive indicator of local tolerance) occurred and no complaints about nasal airflow obstruction were observed. All liposomal formulations had a positive effect on the nasal mucosa, challenged by allergy in some volunteers. CONCLUSIONS AND MESSAGE: Application of liposomal PVP-I spray to the nasal mucosa does not result in any demonstrable limitation of the nasal function nor in detectable damage to the multilayer ciliated epithelium of the nose. Improvement of various parameters of nasal function under liposomal PVP-I suggest improved mucociliary clearance. Explanation could be humidification, improved surfactant (phospholipid) level and/or sufficient mucolytic activity of iodide due to local application of the constituents.

[Efficacy of treatment with Repithel and Jelonet in comparison to treatment with Jelonet alone - a randomized clinical trial in patients receiving meshed skin grafts]. / Wirksamkeit der Behandlung mit Repithel und Jelonet im Vergleich zur alleinigen Anwendung von Jelonet - eine randomisierte klinische Studie an Meshgraft-Transplantationswunden.

UNLABELLED: Moist wound treatment is a well recognized method for the treatment of aseptic acute and chronic wounds. While the moist environment is beneficial to the woundhealing process, it also increases the risk of bacterial superinfection. We here report on the results of a clinical phase-III-study in which we tested the effect of a new PVP-iodine liposomal hydrogel (Repithel) on split-thickness skin grafts. This formulation optimizes moist wound treatment by improving the cell proliferation rate while preventing wound infection. AIM: The aim of this phase-III-study was to analyse the efficacy and tolerance of Repithel in patients receiving meshed skin grafts. METHODS: 167 patients with transplantation wounds were either treated with lipid gauze alone (control group) or with lipid gauze and Repithel. In both groups the extent of neoepithelization, the frequency and severity of graft losses and the time until complete wound closure was achieved were determined. Analysis of the re-epithelization was achieved by photoplanimetry. Impedance measurements gave additional information on the regeneration of the epidermal barrier. RESULTS: Wounds receiving Repithel showed a significantly faster neoepithelisation than wounds which were treated with lipid gauze alone. Treatment with Repithel significantly reduced both the number of graft losses and the size of area lost. The time until wounds were closed completely was significantly shorter in patients receiving Repithel than in controls. The positive effects of Repithel on wound healing were especially observed in smokers, patients with chronic wounds, burns or infected wounds. CONCLUSIONS: Repithel supports healing of meshgraft transplants and reduces the risk of graft loss. Patients who heal poorly benefit particularly from the Repithel treatment.

Repithel: removing the barriers to wound healing.

BACKGROUND: Various standardized and/or validated models exist to test wound healing products. This article discusses their usefulness in clinical practice. OBJECTIVES: Major barriers to wound healing have been identified after intense interaction of research and practitioners. Although extensively tested, wound healing products are still associated with trial and error due to the high variability and complexity associated with the treatment of wounds. Therefore, the results of preclinical testing are compared and contrasted with clinical observations of a liposomal hydrogel containing 3% povidone-iodine (Repithel, PVP-ILH) to assess their expressiveness and to give the practitioner more guidance in application. METHODS: Testing of PVP-ILH included physicochemical testing according to ISO norms, testing in in vitro and in vivo models. The obtained results are compared to the clinical profile of the obtained product in randomized controlled trials and ultimately expressive case studies. RESULTS: PVP-ILH displays good local tolerance, the basis for use in sensitive and predamaged tissue. As observed in laboratory testing, it readily provides moisture and takes up limited amounts of moisture. This was also seen in the clinical testing, as the ability to keep wounds moist and incorporate a certain -- but not large -- amount of exudates. Clinical results also show clean, well-debrided wounds, an effect that (in the absence of an established model for wound cleansing) was traced to the hydrogel component carbomer. DISCUSSION: Recent consensus advocates the concept of wound bed preparation as a systematic approach to removing barriers to healing (TIME). Based on the results, tissue (removing non-viable tissue and debris) and moisture (balance) can now be better understood, and infection/inflammation (control) and edge (progressing, non-advancing or undermining wound edges) are reviewed together with previously published data to assess all aspects potentially impeding wound healing. CONCLUSION: PVP-ILH successfully removes barriers to wound healing, thus laying the foundation to high-quality wound closure. Results from many scientific disciplines can help the user to better understand a product, standardization of testing is the only way of making results comparable.

Effect of polyvinylpyrrolidone-iodine liposomal hydrogel on wound microcirculation in SKH1-hr hairless mice.

AIM: Polyvinylpyrrolidone-iodine liposomal hydrogel (PVP-ILH) is a hydrogel formulation based on polyvinylpyrrolidone-iodine (PVP-I) and liposomes. The beneficial effects of PVP-ILH on wound healing have been previously shown. The aim of this study was to investigate the effects of topically applied PVP-ILH on wound microcirculation. MATERIALS AND METHODS: Experiments were performed on wounds in male SKH1-hr hairless mice (n = 48). Mice were randomized into five treatment groups: mice treated with polyacrylic acid (PAA) and PAA 1:10 as well as PVP-ILH and PVP-ILH 1:10. Mice treated with sodium chloride served as control. Immediately as well as 3, 7, and 14 days after wounding, intravital fluorescent microscopy (IFM) was performed to determine wound surface area and standard microcirculatory parameters. RESULTS: Topically administered PVP-ILH reduced wound size significantly faster compared to controls. Standard microcirculatory parameters, e.g. functional capillary density (FCD) and plasma leakage, showed no differences. FCD increases in all groups after wound creation. Using PVP-ILH, a trend towards higher FCD was observed. CONCLUSION: The wound model in hairless mice in combination with IFM is suitable to qualitatively assess wound microcirculation over a period of 2 weeks even after topical application of pigmented ointments. PVP-ILH showed a positive effect on dermal wound healing and wound microcirculation.

Biological responses to PCB exposure in shorthorn sculpin from Saglek Bay, Labrador.

A local source of polychlorinated biphenyls (PCBs) in Saglek Bay, Labrador, has contaminated marine sediments and the coastal food web. As part of a larger assessment of ecological risks in the Bay, we evaluated biological responses to PCB concentrations in a northern fish species, the shorthorn sculpin (Myoxocephalus scorpius). Biological endpoints, including ethoxyresorufin-O-deethylase (EROD) activity in liver tissue, fish body condition, lipid content, and relative liver mass were examined in 35 sculpin collected during August-September 1999. Across a wide range of PCB concentrations (5.1-6920 ng/g wet weight (ww) in whole fish excluding liver), sculpin showed significant EROD induction (as much as 25-fold in the most exposed group). Responses varied directly with PCB concentrations but there was also an apparent threshold for induction at about 50 ng/g ww (whole fish excluding liver). A strong relationship between sculpin PCB concentrations and the concentrations of PCBs in the marine sediments of Saglek Bay suggests that concentrations above this threshold can arise from very low concentrations in sediments (2.3 ng/g dry weight). Other biological endpoints did not show significant responses to PCB concentrations, nor were they related to the observed EROD activity. Although PCDF compounds were present in trace amounts (primarily 2,3,4,7,8-PnCDF), mono-ortho and non-ortho substituted (coplanar) PCBs appeared to contribute the majority of the total dioxin toxic equivalent (TEQ) concentrations. Overall, the results indicate that biological responses occur in shorthorn sculpin with relatively low PCB concentrations (approximately 50 ng/g), which are not unrealistic for even mildly contaminated areas in northern Canada.

PCBs in sediments and the coastal food web near a local contaminant source in Saglek Bay, Labrador.

Polychlorinated biphenyls (PCBs) were measured in marine sediments and the coastal food web in Saglek Bay, Labrador, to investigate the influence of a local PCB source. Saglek Bay has been the site of a military radar station since the late 1950s and there was PCB-contaminated soil at a beach prior to cleanup in 1997-1999. PCB concentrations in marine sediments during 1997-1999 ranged from 0.24 to 62000 ng/g (dry weight) and decreased exponentially with distance from the contaminated beach. Given this gradient, spatial trends of PCBs in the food web were examined over four zones, according to distance from the contaminated beach: within 1.5 km--zone one, 1.5-4.5 km--zone two, 4.5-7.5 km--zone three, and greater than 7.5 km--zone four. PCB concentrations in a bottom-feeding fish (shorthorn sculpin, Myoxocephalus scorpius), decreased significantly from zone one to zone two, three, four, and distant Labrador reference sites. PCB concentrations in the eggs of a diving seabird (black guillemot, Cepphus grylle) were as high as 48000 ng/g during 1997-1999 and average concentrations in zones one and two were 84 and 13 times higher than in zone four. Marine invertebrates closely reflected the concentrations of PCBs in the associated sediment. In contrast to the benthic-based food web, anadromous arctic char (Salvelinus alpinus) showed no evidence of PCB accumulation from the contaminated sediments. Relatively high PCB concentrations were discovered in some great black-backed gulls (Larus marinus) and ringed seals (Phoca hispida) but appear to relate more to their high trophic level than sampling location. Those species that fed on or near the seabed and had limited foraging ranges were strongly influenced by the local contamination. Total PCB concentrations in the benthic-based food web were significantly higher than background levels for a distance of at least 7.5 km from the contaminated beach. This area is small in the context of widely distributed contamination from long-range transport but the area's high concentrations are comparable to levels associated with adverse effects elsewhere. Our findings should be useful to better assess the environmental impacts of PCB contamination at other coastal sites in the Arctic.

The relative influence of distant and local (DEW-line) PCB sources in the Canadian Arctic.

Soil PCB contamination has been delineated at 18 of 21 Distant Early Warning Line (DEW-line) stations being cleaned up by the Canadian Department of National Defence (DND). As a result, detailed surface soil delineation data has been reported for contamination exceeding 1 microg/g (dw total Aroclor), which is the remedial criteria for PCB contaminated soil under the DEW-line cleanup project. The results of this delineation work has allowed us to estimate the mass of PCB contained in surface soil at these sites and to quantify the DEW-line as a source of PCBs to both local and Arctic wide contamination. Our analysis of DEW-line cleanup delineation reports suggests that pre-cleanup surface soils (top 10 cm) with over 1 microg/g PCB constituted a source of PCBs that ranged from 0.8 to 43 kg with a mean of 18 kg. The total mass of PCB at all 18 sites was 119 kg. Previous studies have described a "halo-effect" that surrounds DEW-line sites, whereby PCB signatures in soil and plants up to 10 km from source areas were attributed to the local source. At Cambridge Bay (CAM-M), Nunavut, our inventory of PCB sources and redistribution suggests that up to 3.4 kg of PCB were exported from the site to the surrounding tundra prior to cleanup. The primary mechanism of transportation appears to be wind borne particulate. Potential vapour phase emissions of PCB from contaminated soil at DEW-line sites appears to have been negligible.