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Displaying: 81 - 100 of 103 Next
81. Health effects of increased UV exposure

Besides some beneficial effects of UV exposure, i.e. skin tanning and vitamin D production, UV ex-posure can have deleterious effects on human health. Deleterious effects are a.o. skin cancer, skin aging, wrinkling, cataract, snow blindness, and effects on the immune system. The objectives of this project are especially aimed at the detection of UV effects on the human immune system and as a consequence of the UV induced immunomodulation effects on the resistance to infections and tumors. Research activities Research activities are focussed at laboratory animal studies, studies with human volunteers, epidemiology and mathematical modelling.

Biological effects epidemiology UV radiation immunology Exposure Human health
82. 'NAR-2000' expedition

The 'NAR-2000' expedition was performed during August-September 2000. The overall programme of work includes: - monitoring of pollution in air, waters and bottom sediments of freshwater lakes, soils and terrestrial vegetation - soil/botanical studies - visual and remote sensing (aerial photos and video surveys) studies of damage to soil and vegetation cover. Samples of river water and bottom sediments from 25 freshwater bodies and samples from 16 terrestrial sites in the area of the Varandey and Toravey oil fields were taken for chemical analyses.

Biological effects Organochlorines PCBs Soils Catchment studies Heavy metals PAHs Pollution sources phenols Petroleum hydrocarbons Forest damage soil damage Persistent organic pollutants (POPs) Local pollution Sediments Atmosphere Oil and Gas Temporal trends detergents
83. Concentrations and interactions of selected elements in tissues of four marine mammal species harvested by Inuit hunters in arctic Alaska, with an intensive histologic assessment, emphasizing the beluga whale

The first part of the present study evaluated tissue concentrations of twelve essential and non-essential elements in four arctic marine mammal species important as subsistence resources to indigenous Alaskans. Species sampled included: bowhead whales, beluga whales, ringed seals, and polar bears. Concentrations of As, Cd, Co, Cu, Pb, Mg, Mn, Hg, Mo, Se, Ag, and Zn, were analyzed in liver, kidney, muscle, blubber, and epidermis (the latter in cetaceans only). Elements that were identified as having tissue concentrations, which in domesticated species would have been considered higher than normal and/or even toxic, were Cd, Hg, Ag, and Se. However, the concentrations of these elements were consistent with previous reports for arctic marine mammals. Remaining elements were at concentrations within normal ranges for domesticated species, although Cu was found frequently at concentrations that would be considered marginal or deficient in terrestrial domesticated animals. Across-species comparisons revealed that Cd was highest in kidney, followed by liver in all four species. Its concentrations were frequently correlated with Cu, Zn, Hg, and Se. Cadmium accumulated with age in bowhead and beluga whales, especially in liver and kidney. The relationships between Cd and Hg, and between Cd and Se were believed to be due to mutual accretion with age, although direct interactions could not be ruled out, especially with respect to Cd and Se. Associations between Cd and Cu, and Cd and Zn were potentially attributable to mutual binding with the inducible protein, metallothionein. This assumption was supported by the observation that Cd:Zn ratios in liver and kidney displayed a significant linear relationship to age and that this ratio either increased slightly (in kidney and liver of bowheads) or remained constant (in kidney and liver of belugas) with age. In general, Se was highest in liver and kidney of all four species, where it was frequently at concentrations that would have been deemed elevated or toxic for domesticated species, although within ranges previously reported for arctic marine mammals. Selenium increased with age indices, and was highly correlated with Hg, and often with Cd as well. Mercury also increased with age, and liver contained the highest tissue concentration in the cetacean and pinniped species. The pattern of Se accumulation in polar bears differed, with highest concentrations found in kidney, which suggested that this tissue may be the primary site for Hg detoxification in this species, as is the case for terrestrial mammals. Compared to the other three species, bowhead whales had very low Hg concentrations in all tissues. The highly significant linear relationship between Hg and Se noted in various tissues (particularly liver) of all four species was presumed due to binding of these two elements to each other following demethylation of MHg. This assumption was supported by the observations that while Se and Hg both accumulated with age, the fraction of total Hg that was composed of MHg decreased with age. The quantity that represented the difference between total Hg measured directly and calculated total Hg [i.e., SHg = Hg(II) + MHg], also increased with age in beluga liver. This connoted that a portion of the total Hg present was in an organic form other than MHg, and that this form accumulated with age. Alternatively, this portion, which was apparently not measured by either the Hg(II) or MHg procedures, may have been lost during extraction. Species in this study had mean hepatic Hg:Se molar ratios that were below unity. This implies that Hg concentrations may have been below some threshold level, after which subsequent accumulation proceeds in a 1:1 molar ratio fashion with Se. Alternatively, it might suggest that a 1:1 Hg:Se molar ratio is not a prerequisite for protection from Hg toxcosis among marine mammals, because none of the animals in the present study exhibited lesions typically associated with Hg toxicosis. In beluga liver, concentrations of Ag were elevated when compared to domesticated species. The only element that showed a significant linear association to Ag was Cu—a relationship that was observed in all four species. This suggested that Ag and Cu may be associated through a common ligand, possibly metallothionein. The association between Ag and Se in beluga liver was less strong than that between Hg and Se; moreover, Ag did not increase with age. These findings indicate that Ag probably does not compete with Hg for Se binding, and therefore is unlikely to substantially inhibit detoxification of Hg in beluga whales. In the second portion of this research, tissues from bowhead whales, beluga whales and ringed seals were examined at both the gross and light microscopic level. The purpose of this evaluation was three-fold: to describe the normal histologic appearance of tissues; to perform a routine histologic survey of tissues that would contribute to a general health assessment, and; to scrutinize tissues for lesions that might support a diagnosis of toxicosis caused by Cd, Hg, Ag, or Se. Tissues examined were chosen on the basis of their propensity to be targets for toxicologic injury from the specified elements (with the exception of brain) and included, but were not limited to, the tissues analyzed chemically. Special stains were used to identify particular pigments or tissue components. Overall, the bowhead whales evaluated appeared healthy and had low parasite burdens. The most common lesion, which was observed in all bowheads, was a non-inflammatory chronic renal periglomerular and interstitial fibrosis. This lesion was not typical of Cd-induced nephropathy, and it did not appear to be associated with renal Cd burdens. Nevertheless, thresholds of Cd-induced renal injury are not known for cetacean species, and more whales need to be examined histologically in conjunction with analysis of tissue Cd residues. Acute myodegeneration was observed in cardiac and/or skeletal muscle of a few bowheads, and was presumed to reflect a hunting-induced exertional myopathy. The beluga whales examined were generally in good body condition and appeared healthy grossly, but they had much higher parasite burdens than bowhead whales. In particular, prevalence in belugas of pulmonary nematodiasis was high, being especially common among whales obtained from Pt. Hope compared to those from Pt. Lay. Grossly, firm, caseous nodules were associated with lungworms, while histologically, the associated pulmonary changes ranged from mild chronic inflammation and focal granuloma formation to catarrhal granulomatous and eosinophilic verminous bronchopneumonia. Another change observed in some belugas and believed to be associated with lungworm infection, was multifocal pulmonary arterial medial hypertrophy and degeneration. Beluga whales harvested at Pt. Lay (summer) frequently showed evidence of hepatic and pancreatic atrophy, while whales taken at Pt. Hope (spring) did not. This was believed to result from anorexia during migration—a supposition corroborated by the lack of stomach contents among Pt. Lay whales. Another prominent histologic finding among belugas was hepatic telangectasia, which occurred with significantly greater frequency and severity in Pt. Hope belugas than in those from Pt. Lay. The etiology and significance of this lesion could be not be ascertained, although it was not believed to be associated with any of the elements analyzed in this study. Mild thickening of Bowman’s capsule was seen frequently in belugas. However, this lesion was not typical of Hg or Cd-induced nephropathies, and did not appear correlated with kidney concentrations of these metals. This lesion was believed to be a normal consequence of aging in belugas, although a metal etiology for it could not be excluded irrefutably. In general, ringed seals were in good body condition and appeared healthy on gross examination. Among seals evaluated histologically, the most common finding was a mild, chronic, focal or periportal hepatitis, with focal hepatocellular necrosis sometimes apparent. Although a metal etiology for this lesion could not be definitively ruled out, in the absence of other lesions that would support a diagnosis of metal toxicosis, an infectious etiology was considered more credible. Two out of sixteen seals had embryologic remnants (an epidermoid cyst and an ultimobranchial cyst)—lesions that are usually considered incidental. While no toxic (metal or otherwise) etiology could be ascertained for these lesions, the incidence of retained embryologic remnants seemed high. A number of xenobiotics are known to be endocrine-disruptors, and the potential for such an etiology among these seals should be examined further. Lipofuscin deposition was ubiquitous among all three species examined histologically. Lipofuscin was most prevalent in hepatocytes, but also commonly was observed in various other tissue and cell types, especially in cardiac and skeletal myocytes, and in uriniferous tubular epithelial cells. The third portion of this study employed autometallographic (AMG) development of light microscopic tissue sections to amplify and localize deposition of inorganic Hg in liver and kidney of beluga and bowhead whales. No staining occurred among bowhead tissues, confirming the extremely low concentration of Hg determined through chemical analyses. In beluga kidney sections, AMG granules were seen throughout the uriniferous tubular epithelium, showing that Hg deposits throughout the nephric tubule, and not solely in the proximal tubular epithelium. In liver tissue, AMG granules were deposited primarily in periportal regions among whales with lower hepatic Hg burdens. In addition to periportal deposition, AMG granules were observed in pericentral and mid-zonal regions in the belugas sampled that had higher liver Hg concentrations (generally older animals). Granules were densely concentrated in stellate macrophages, especially near portal triads. Granules also were distributed in hepatocellular cytoplasm, generally concentrated toward the bile cannalicular domain of the cell. Granules were discrete, potentially indicating that Hg was confined within lysosomes. These observations suggested that inorganic Hg deposits initially in periportal regions of young animals, with subsequent accumulation occurring pericentrally, and finally, midzonally as the whales age. Computer-assisted densitometric analysis was used for semi-quantitative evaluation of AMG staining intensities. These AMG staining intensities were well correlated with concentrations of Hg determined via chemical analysis. Areas with AMG-staining were identified and compared with location of lipofuscin in the same field, visualized with fluorescent microscopy. While AMG granules and lipofuscin deposits sometimes were co-localized, they more often were not. In addition, abundant lipofuscin deposition was seen in livers of younger belugas with little to no Hg-catalyzed AMG staining. Also, lipofuscin concentrated predominantly in pericentral regions. These observations suggested that in the healthy marine mammals of this study, marked hepatic lipofuscin deposition most often occurred independently of Hg accumulation. Consequently, hepatic lipofuscin is likely to be a poor indicator of Hg-induced damage in belugas. The abundant lipofuscin deposition in livers of marine mammals was interpreted as most likely denoting a heightened exposure to oxidative stress that is probably inherent to a marine mammalian existence. These oxidative stressors may include a diet high in polyunsaturated fatty acids (PUFAs), alternating hypoxia and abundant oxygenation, and periodic bouts of anorexia associated with migration.

histology Biological effects Heavy metals health assessment Polar bear Arctic histopathology Marine mammals
84. Radionuclide contaminant burdens in arctic marine mammals harvested during subsistence hunting

We conducted gamma spectrometric analyses on more than 200 arctic marine mammal tissue samples. These samples were primarily provided by subsistence hunters from northern Alaska, with a smaller number of samples from the Resolute region in Canada. The majority of samples (>90% ) had detectable levels of the anthropogenic radionuclide 137Cs, with a mean level observed in all samples of 0.67 Bq kg-1 dry weight ±0.81 (SD). Converted to wet weight, the mean was 0.21 Bq kg-1 ±0.19 SD. The median activity observed was 0.45 Bq kg-1 dry weight (0.18 Bq kg-1 wet weight) with a range from detection limits to 6.7 Bq kg-1dry weight (1.1 Bq kg-l wet weight). These findings confirm expectations that current anthropogenic gamma emitter burdens in marine mammals used in the North American Arctic as subsistence food resources are well below activities that would normally merit public health concern (~1000 Bq kg-1 wet weight). Some differences among species and tissues were observed. Beluga tissues had slightly higher mean burdens of 137Cs overall, and epidermis and muscle tissues in bowhead and beluga whales typically had higher burdens than other tissues analyzed. Low levels of the neutron activation product l08mAg (half-life 418 yr.), probably bioaccumulated from bomb fallout sources, were observed in 16 of 17 beluga livers analyzed, but were not found in any other tissues of beluga or in any other species sampled. A subset of 39 samples of various tissues was analyzed for the alpha and beta emitters 239,240Pu and 90Sr. Plutonium levels were near the threshold of detectability (~0.1 Bq kg-1 dry weight) in 6 of the 39 samples; all other samples had no detectable plutonium. A detectable level of 90Sr (10.3 ±1.0 Bq kg-1 dry weight) was observed in only one of the 39 samples analyzed, a bowhead epidermis sample. Although the accumulation of 108mAg has not been previously reported in any marine mammal livers, all of our analytical measurements indicate that only very low levels of anthropogenic radioactivity are associated with marine mammals harvested and consumed in the North American Arctic.

silver-108m cesium-137 Radionuclides Arctic Marine mammals
85. Effects of Persistent Organic Pollutants (POPs) on the Immune Response of Glaucous Gull (Larus hyperboreus)

The present project includes one pilot study of wild adult glaucous gull (Larus hyperboreus) and one experimental study of glaucous gull chicks raised in captivity. The pilot study of adult gulls gave us enough blood and tissue samples to develop the methods needed for immune system analysis in the laboratory experiment. In the experimental study a total of 39 glaucous gull chicks were hatched and raised in captivity in Svalbard, Norway. The chicks were divided into two groups. One experimental group (20 chicks) was given food that mimicked the “natural” food found in the marine environment. The control group (19 chicks) was given “clean” food. After 56 days the chicks were sacrificed in order to collect samples for analyses of organochlorines (OCs) and immunocompetence measurements. The experimental group had 2.8, 3.9, 5.0, and 6.1 time’s higher concentrations of HCB, Oxychlordane, ?DDT, and ?PCB, respectively, compared to the control group at day 56. All chicks used in the experiment were immunised with various vaccines and sera in order to test their ability to respond against foreign antigens. The experimental chicks produced low levels of virus neutralising antibodies when tested against the herpes virus and reovirus. They produced higher levels of neutralising antibodies when tested to tetanus toxoid. There was, however, no difference between the experimental groups with regard to the mean antibody titres. The chicks in both groups also responded to the influenza virus by increasing the production of specific antibodies. However, the mean antibody titre in the exposed group was significantly lower than in the control group. The mitogen-induced response of blood lymphocytes to PHA and LPS was significantly higher in the exposed group compared to the control group. The specific response of blood lymphocytes to Con A, PWM, KLH, TET, and PPD was higher in the exposed group compared to the control group. However, do to high variance in the exposed group there was no significant difference between groups with regard to the lymphocyte response to these mitogens. The results from the present study indicate a toxic effect of OCs on the glaucous gull chicks, which induced a systematic activation of the immune system. Further work on data will be performed.

effects Biological effects Organochlorines PCBs Fish Long-range transport glaucous gull Persistent organic pollutants (POPs) Seabirds immune system Pesticides
86. Monitoring of forest damage in the eastern region of Finnmark, Norway

The aim of the project is to monitor forest health in the border areas between Norway and Russia. The impact on the forest ecosystems in the border areas is varying. In the areas close to the nickel smelter (in Nikel), the damage is serious, while the damage on the Norwegian areas are much less. Here the damage is mostly related to lack of lichen vegetation on birch stems. The moss vegetation in the bottom layer is also influenced. In some cases, when certain weather conditions fell together with high emissions of sulphur dioxide, visible damage has been developed on leaves of shrubs and trees, even on Norwegian territory. Even the emission normally does not cause visible damage on Norwegian territory; chemical influenced is traced over large Norwegian areas

Biological effects Biology Lichens Soils Heavy metals Acidification Monitoring vegetation Forest damage Biodiversity Food webs Ecosystems Mineral nutritients in plants
87. Intensive monitoring of forest ecosystem in an air pollution gradient from Nikel and westwards

The aim of the project Intensive monitoring of forest ecosystem in an air pollution gradient from Nikel and westwards, running in the period 1994-1998/99, has been to develop and perform environmental monitoring in the border areas between Norway and Russia. The project is a contribution to the joint Norwegian/Russian Environmental Co-operation. Russian scientists have established and performed analyses at four monitoring sites in Russia, while Norwegian scientists have done similar monitoring at adjacent Norwegian areas. The scientists have worked together in two workshops and in the field. The collaboration has been efficient carried out by extensive use of e-mail. An important result for of the project has been harmonised field methodology, which has been put into practice by means of common fieldwork. The impact on the forest ecosystems in the border areas is varying. In the areas close to the nickel smelter (in Nikel), the damage is serious, while the damage on the Norwegian areas are much less. Here the damage is mostly related to lack of lichen vegetation on birch stems. The moss vegetation in the bottom layer is also influenced. In some cases, when certain weather conditions fell together with high emissions of sulphur dioxide, visible damage has been developed on leaves of shrubs and trees, even on Norwegian territory. Even the emission normally does not cause visible damage on Norwegian territory; chemical influenced is traced over large Norwegian areas

Soil water Biological effects Biology Lichens Soils Heavy metals Acidification Monitoring vegetation Forest damage Biodiversity Food webs Ecosystems Mineral nutritients in plants
88. Terrestrial monitoring programme. Studies in vegetation ecology of boreal birch forests in Børgefjell National Park, N Norway

In 1990, the Directorate for Nature Management (DN) established an area for integrated monitoring within Børgefjell National Park, Røyrvik, N Trøndelag. Studies of vegetation-environment relationships in the area was performed by NINA. The area includes both subalpine birch forest and low alpine heath. The new established vegetation investigation included all together 80 different species. This material was processed numerically by using multivariate methods. Indirect gradient analyses were performed using Detrended Correspondence Analysis (DCA) and Local Nonmetric Multidimentional Scaling (LNMDS). Direct gradient analyses were performed by using rescaled hybrid Canonical Correspondence Analysis (CCA). Non-parametric correlation analyses, Kendall’s , were performed between environmental parameters and DCA axis values. The results of the numerical and statistical processing were used partly to provide a description of the vegetational structure in the material and partly to quantify how much each ecological parameters contributed to determination of vegetational structure. This work shows the species distribution along various complex gradients; moisture, nutrient conditions, light etc. The investigation is primarily designed to study vegetation dynamics along these gradients and whether changes in the number of species can be related to changes in physical, biotic and, not least, chemical parameters. Variance analysis was performed to assess to what extent the sample plots tends move in a determined direction from 1990 to 1995. The variation between the years were not significant along the primary complex gradients, but there were a significant displacement of species along the following gradients. The most important species were: Vaccinium vitis-idaea, Melampyrum sylvaticum and Hylocomium splendens), which showed an increase and some cryptogams like Brachythecium reflexum, B. salebrosum and Cladonia ecmocyna which declined.

Biological effects Biology Populations Soils Mapping Heavy metals Long-range transport Acidification Spatial trends Environmental management Climate change Forest damage Modelling Emissions Exposure Biodiversity Local pollution GIS Data management Temporal trends Ecosystems
89. Monitoring terrestrial ecosystems: Ecological investigation of vegetation in the boreal birch forest of Dividalen National park, county Troms, Norway.

In 1993, the Directorate for Nature Management (DN) established a new area for the monitoring of terrestrial ecosystems in Dividalen National Park in Troms County. This report presents the reanalysis of vegetation and soil from this terrestrial monitoring area. The area in Dividalen is located in the northern boreal birch forest, in a relatively continental section where the dominant type of vegetation is bilberry-mountain crowberry birch forest (A4c). The structure of the vegetation is analysed by multivariate methods (ordination). In Dividalen all together 131 species were found; 75 vascular plants, 18 mosses, 14 liverworts and 24 lichens. This is a decrease from the number of species recorded in 1993 when 141 species were found in the same mesoplots: 74 vascular plants, 24 mosses, 18 liverworts and 25 lichens. The decrease was not significant for the total number of species or for the total number of vascular plants. However the total number of cryptogames showed a slight significant decrease in number between 1993 and 1998. This may be due to increased cover of several ericoid species. In Dividalen we found no significant changes in vegetation composition for the periode 1993 – 1998 along the first four ordination axes. However, there were changes in mesoplots with high DCA1 values. The changes were in the direction towards lower species richness. Species like Myosotis decumbens, Poa alpina, Solidago virgaurea, Cerastium fontanum and Rumex acetosa ssp. lapponicus showed the largest decrease in these mesoplots. Species that showed the largest increase were Vaccinium vitis-idaea, Mnium spinosum and Polytrichum juniperinum. We have found no relations between these changes and acidification due to deposition of pollutans. Lack of disturbance factors in the area in the last years, which favours an increase in ericoid vegetation, is the probable explanation for the changes.

Biological effects Populations Long-range transport Acidification Spatial trends Environmental management Climate change Forest damage Biodiversity GIS Temporal trends Ecosystems
90. Effects of persistent organic pollutants on polar bears in Svalbard

The study covers many areas of ecotoxicology research on polar bears. Monitoring of POP levels and studies of effects on endocrine disruption, immune system, reproduction, and demography are all parts of the study.

Biological effects Biology Populations Organochlorines PCBs Heavy metals Spatial trends Climate change Polar bear Persistent organic pollutants (POPs) Reproduction Pesticides Temporal trends Marine mammals
91. Environmental Assessment in van Mijenfjorden, Svalbard

The project aims to describe the environmental status of marine sediments in van Mijenfjorden. This to provide baseline data of contaminants and biodiversity, as well as for monitoring of eventual contamination from industrial activities (coal mining).

Biological effects Glaciers Biology Populations Discharges Spatial trends Environmental management Mining Oceanography Biodiversity Arctic Sediments Temporal trends Ecosystems
92. Environmental Protection from Ionising Contaminants in the Arctic (EPIC)

(1) Collate information relating to the environmental transfer and fate of selected radionuclides through aquatic and terrestrial ecosystems in the Arctic. (2) Identify reference Arctic biota that can be used to evaluate potential dose rates to biota in different terrestrial, freshwater and marine environments (3) Model the uptake of a suite of radionuclides, both natural and anthropogenic to reference Arctic biota (4) Develop a reference set of dose models for reference Arctic biota (5) Compile data on dose-effects relationships and assessments of potential radiological consequences for reference Arctic biota (6) Integrate assessments of environmental impact from radionuclides with those for other contaminants.

Pathways Biological effects Radioactivity Radionuclides Modelling Arctic
93. Benthic fauna in the Kongsfjorden, Svalbard

Investigation of benthic faunal communities for: taxon distribution/ biodiversity mapping; examination of effects of glacial and physical disturbance on community structure; relation between faunal structure and sediment contaminants.

Biological effects Glaciers Biology Mapping Physical disturbance Spatial trends Pollution sources Environmental management Climate change Biodiversity Arctic Sediments Temporal trends Ecosystems
94. Environmental assessment of the Isfjorden complex, Svalbard

The project aims to carry out an environmental assessment of the marine environment close to the three main settlements in the Isfjorden complex; Barentsburg, Longyearbyen and Pyramiden. The study comprises analyses of sediment geochemistry and soft-bottom benthic fauna. Attention is given to distinguishing atmospheric transport of contaminants from those arising from local sources.

Biological effects Sources Pollution sources Contaminant transport Mining Primary recipient Radionuclides Modelling Dioxins/furans Sediments Pesticides Waste secondary recipient Biology Organochlorines PCBs Mapping Heavy metals PAHs Long-range transport Discharges Spatial trends Environmental management Petroleum hydrocarbons Biodiversity Arctic Persistent organic pollutants (POPs) Local pollution Data management Temporal trends Ecosystems
95. Effects of metals and POPs on marine fish species

To clarify whether metals and/or POPs affect marine fish species - Atlantic cod (Gadus morhua) and plaice (Pleuronectes platessa)

Biological effects PAH-metabolites Organochlorines Pleuronectes platessa Heavy metals Fish EROD PAHs Long-range transport Gadus morhua ALA-D metallothionein
96. Metal effects in Arctic seals

To clarify whether effects of metals (Cd, Hg) affects biochemical markers (MT) in seal kidneys

Biological effects kidney Cd seal metallothionein Marine mammals
97. Monitoring epiphytic lichens on birch (Betula pubescens)

The aim of this project is to monitor epiphytic lichen communities in a way that enables us to separate between natural variation and the effects of acidification and long range transported air pollutants.

Biological effects Long-range transport Acidification Epiphytic lichens Biodiversity Temporal trends Birch forests
98. Endocrine disruption in arctic marine mammals

Assess the effects of POP mixtures present in the food on the endocrine system of marine mammals. Effects of these mixtures on steroid synthesis in adrenals and gonads will be studied in vitro. Further, hormone mimicking effects of contaminant mixtures will be studied. Contaminant receptor binding and responses of the contaminant-receptor complex are studied using estrogen/androgen receptor binding assays in combination with reporte gene assays.

Biological effects Arctic Persistent organic pollutants (POPs) Marine mammals
99. Xenobiotic impact on Arctic charr: Nutritional modulation and physiological consequences

The objectives are to test the hypothesis that the tissue re-distribution of PCB are linked to the metabolic status of the Arctic charr and that the tissue re-distribution of PCB associated with fasting will decrease the overall performance characeristics of the Arctic charr.

Biological effects Organochlorines PCBs Fish Exposure Persistent organic pollutants (POPs)
100. Mercury in Salluit : phase 2 : Effects of mercury on oxydative status and sensorimotor functions

Among all contaminants present in different aquatic ecosystems in Canada, methylmercury (MeHg) is a major source of concern for public health. Currently, it is difficult to reliably determine the threshold of MeHg concentration at which functional changes occur. On the other hand, it is well known that chronic MeHg exposure is very harmful for the nervous system. Oxidative reactions appear to be of central importance to mercury toxicity. Therefore, it is important and urgent to determine with precision the minimal dose at which oxidative stress and neurotoxic effects can be identified since some studies suggest that MeHg toxicity can be detected at level far below the minimal exposure level proposed by the World Health Organization. The main goal of this project is to investigate the effects of mercury on sensorimotor functions in the population of Salluit. We will examine the relationship between the level of MeHg and sensorimotor performance. Afterwards, specific recommendations based on quantitative evidence will be made to the concerned populations so as to diminish long-term risk on health.

Biological effects Populations Heavy metals Fish Indigenous people Exposure Diet Temporal trends Human health Human intake