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At least 127 records · Page 7Linked to original sources
PubMed1996

Analysis of organochlorine pesticides using solid-phase microextraction.

A solid-phase microextraction (SPME) procedure has been developed to successfully extract eighteen chlorine-containing pesticides from water. A fused-silica fiber coated with a non-polar polydimethylsiloxane stationary phase was used to extract the analytes from water samples over a concentration range of 0.001 to 100 ng/ml. Limits of detection at a ng/l level were achieved with GC and flame ionization detection, and improved to sub ng/l levels using GC-MS, or GC with electron-capture detection (ECD). The reproducibility of the measurements between fibers was found to be very good, with precision typically below 20% R.S.D. within a single fiber. Qualitative analysis was performed on river and lake samples from Southern Ontario. Samples from the Arctic region of Canada were analyzed quantitatively using a dual ECD system.

Arctic Regions↗
PubMed2003

Arctic health policy: contribution of scientific data.

In Western Hemisphere arctic regions, scientific findings in humans, wildlife, and the environment have resulted in major governmental policy formulations. Government policy resulted in establishment of an effective international organization to address scientifically identified problems, including health disparities in arctic indigenous populations. Western scientific data and indigenous knowledge from initial international programs led to international agreements restricting certain persistent organic pollutants. In recent years, scientific data, and indigenous traditional knowledge, have resulted in governmental policy in the United States, Canada, and Nordic countries that includes the full participation of indigenous residents in defining research agendas, interpreting data, communicating information, and local community policy formulation.

Adolescent↗
PubMed1990

An outbreak of toxoplasmosis in pregnant women in northern Québec.

An ongoing screening program for toxoplasmosis identified a cluster of four women from northern Québec who, over a 4-month period, seroconverted during their pregnancy. An epidemiologic investigation was carried out in an attempt to identify the source of this infection. All potential risk factors were assessed by a questionnaire administered to 22 Inuit women who had delivered babies in the previous year. Seroconversion was significantly associated with skinning of animals for fur (P = .015) and frequent consumption of caribou meat (P = .034). Compared to seronegative women, women who were seropositive were more than four times more likely to have eaten dried seal meat (P = .067), more than six times more likely to have eaten seal liver (P = .064), and more than eight times more likely to have consumed raw caribou meat more than once per week (P = .054). These observations have contributed to the development of guidelines for the prevention of toxoplasmosis in seronegative pregnant women in this arctic region.

Adolescent↗
PubMed2005

Polybrominated diphenyl ethers in airborne particulates collected during a research expedition from the Bohai Sea to the Arctic.

In July to September 2003, particulates in the oceanic atmosphere from the Bohai Sea to the high Arctic (37 degrees N to 80 degrees N) were collected aboard a research expedition icebreaker, Xuelong (Snow Dragon), under the 2003 Chinese Arctic Research Expedition Program (CHINARE 2003). These samples were analyzed to elucidate the atmospheric distributions of polybrominated diphenyl ethers (PBDEs) in the North Pacific Ocean and adjacent Arctic region. The levels of 11 PBDE congeners (BDE-28, -47, -66, -100, -99, -85, -154, -153, -138, -183, and -209; the sum was defined as sigma11PBDE) in the oceanic atmosphere of Far East Asia (34-48 degrees N/122-148 degrees E) ranged from 2.25 to 198.9 pg/m3 with a mean of 58.3 pg/m3. BDE-47, -99, -100, and -209 were the dominant congeners in all the samples, suggesting that the widely used commercial penta- and deca-BDE products were the original sources. The PBDE levels exhibited a decreasing trend from the mid- to high-latitudinal regions of the North Pacific Ocean, probably resulting from dilution, deposition, and decomposition of PBDEs during long-range transport of air masses. On the other hand, no apparent geographical pattern of PBDE distribution was observed within the Arctic, attributable to unstable air circulation and strong air mixing. Correlations among the PBDE congeners suggested that air masses collected from the North Pacific Ocean were relatively fresh, whereas those from the Arctic were aged as a result of photodecompoisiton. The higher average level (17.3 pg/m3) of PBDE congeners in the Arctic than those in the adjacent North Pacific Ocean (12.8 pg/m3) or other remote areas reported in the literature was attributed to the impact of the North American continent and temperature effects, which was consistent with the hypotheses of global fractionation.

Air Movements↗
PubMed2006

Research with Arctic peoples: unique research opportunities in heart, lung, blood and sleep disorders. Working group summary and recommendations.

Arctic peoples are spread over eight countries and comprise 3.74 million residents, of whom 9% are indigenous. The Arctic countries include Canada, Finland, Greenland (Denmark), Iceland, Norway, Russia, Sweden and the United States. Although Arctic peoples are very diverse, there are a variety of environmental and health issues that are unique to the Arctic regions, and research exploring these issues offers significant opportunities, as well as challenges. On July 28-29, 2004, the National Heart, Lung, and Blood Institute and the Canadian Institutes of Health Research co-sponsored a working group entitled "Research with Arctic Peoples: Unique Research Opportunities in Heart, Lung, Blood and Sleep Disorders". The meeting was international in scope with investigators from Greenland, Iceland and Russia, as well as Canada and the United States. Multiple health agencies from Canada and the United States sent representatives. Also attending were representatives from the International Union for Circumpolar Health (IUCH) and the National Indian Health Board. The working group developed a set of ten recommendations related to research opportunities in heart, lung, blood and sleep disorders; obstacles and solutions to research implementation; and ways to facilitate international comparisons. These recommendations are expected to serve as an agenda for future research.

Arctic Regions↗
PubMed1999

Does winter darkness in the Artic protect against cancer? The melatonin hypothesis revisited.

The melatonin hypothesis states that excess exposure to environmental light may contribute to breast cancer risks via impaired pineal secretion of melatonin. A corollary, not considered previously, is that a net annual increase in oncostatic melatonin would be expected in persons who experience a light deficit during extended winter darkness periods; thus, hormone-dependent cancers should occur less frequently in people who reside north, rather than south, of the Arctic circle. Consistent with our prediction, epidemiological data indicate uniformly low risks for hormone-dependent cancers in the Arctic. The available literature on genetic, reproductive, nutritional, life-style, and environmental risk factors provides no obvious clues to the observed cancer patterns. Moreover, diurnal and 24-hour melatonin concentrations in humans living in Arctic regions were reported as high in November-January, when light intensity is low. Since these observations are consistent with our corollary and the associated prediction, we suggest that research on a melatonin-inhibited carcinogenesis in the low-risk populations of the Arctic should be pursued.

Alaska↗
PubMed2001

Bioaccumulation of persistent organic pollutants in lichen-caribou-wolf food chains of Canada's Central and Western Arctic.

While biomagnification of persistent organic pollutants (POPs) in aquatic food chains is well documented, there have been few investigations of the trophodynamics of POPs in Arctic terrestrial food chains. This study presents field-collected concentration data and corresponding fugacities of various hydrophobic organic chemicals (ranging in octanol-water partition coefficients or K(OW) from approximately 10(3.8) to 10(9)) in two lichen species (Cladina rangiferina and Cetraria nivalis), willow leaves (Salix glauca), barren-ground caribou (Rangifer tarandus), and wolves (Canis lupus) from Canada's Central and Western Arctic region. The results show that, in contrast to aquatic food chains, persistent substances including beta-hexachlorocyclohexane and 1,2,4,5-tetrachlorobenzene with a K(OW) <10(5) can substantially biomagnify in lichen-caribou-wolf food chains in Canada's Central and Western Arctic. Strong positive correlations between the biomagnification factor and the octanol-air partition coefficients (K(OA)) of nonmetabolizable compounds were observed in wolves. In caribou, the biomagnification factors dropped slightly with increasing K(OA). K(OA) proved to be a better indicator of biomagnification than K(OW). Current management policies that consider only chemicals with K(OW) values >10(5) as bioaccumulative substances fail to identify substances that have the potential to biomagnify in Arctic terrestrial food chains despite a low K(OW) because of a high K(OA).

Animals↗
PubMed1996

Organochlorine residues in marine mammals from the northern hemisphere--a consideration of the composition of organochlorine residues in the blubber of marine mammals.

Levels of organochlorines (PCBs, sigma DDT, lindane and its isomers, HCB, chlordane, and toxaphene) were determined in blubber of marine mammals from the northern hemisphere. Differences in both levels and ratios of organochlorine compounds were detected in different species of marine mammals living in the same region, e.g. blubber of harbour seals (Phoca vitulina) accumulated significantly lower levels of lindane, HCB, toxaphene, and DDT and its metabolites than harbour porpoises (Phocoena phocoena). Compared to such elementary differences in the organochlorine pattern in different marine mammals, the influence of age and sex on the results was only minimal. Varying ratios of contaminants in individual harbour porpoises were explained by migration. Constant PCB/DDT ratios were measured in harbour seals. Due to the sedentariness of harbour seals, even local sources of contaminants could be recognized. Careful evaluation of the organochlorine levels and ratios in marine mammals made it possible to monitor the transport of PCBs from the European continent to European Arctic regions.

Adipose Tissue↗
PubMed1997

Giardiasis in ringed seals from the western arctic.

Sixteen beluga whales (Delphinapterus leucas) and fifteen ringed seals (Phoca hispida) from the western arctic region of Canada were examined for giardiasis and cryptosporidiosis. Intestinal contents from the rectum and colon were collected from animals slaughtered by Inuit hunters. A fluorescent monoclonal antibody identified Giardia sp. cysts in three of 15 (20%) seals. Thus, ringed seals are implicated as a potential reservoir for this zoonosis in the arctic.

Animals↗
PubMed1978

[Epidemiology of rabies (author's transl)].

Rabies is widespread in all continents except Australia. As an anthropozoonosis its main importance is in areas with uncontrolled dog rabies, nowadays principally topical and subtropical regions. The greatest economic losses however are encountered in the cattle herds of South and Central America, where paralyssa prevails. In the northern hemisphere particularly rabies is enzootic among wildlife. Under the given ecological conditions only one or two species act as primary vectors of the infection. In Europe and parts of North America the red fox, in the arctic regions the arctic fox; in the middle West of the USA the skunk and in smaller foci the raccoon and mongoose are the reservoirs of rabies.

Animals↗
PubMed2000

Induced pigmentation in zooplankton: a trade-off between threats from predation and ultraviolet radiation.

Ultraviolet (UV) radiation is harmful to all life, and the ongoing depletion of the ozone layer is likely to affect interactions among both terrestrial and aquatic organisms. Some organisms have evolved adaptations to reduce radiation damage, such as the various types of protective pigmentation of freshwater zooplankton. However, strong pigmentation also increases vulnerability to visually hunting predators. Hence, where both UV radiation and predation are intense, zooplankton may be sandwiched between conflicting selective pressures: to be pigmented and to be transparent at the same time. Here, I show that the level of pigmentation in copepods is up to ten times higher in lakes without predatory fishes than where fishes are present. Moreover, animals from the same population exposed to either UV light or predator scent showed a 10% difference in pigmentation after only four days, suggesting that pigmentation is an inducible trait. Hence, individual copepods are not passive victims of selective predation or radiation damage, but adjust the level of pigmentation according to the prevailing threat. The ability to adjust pigmentation level rapidly may be especially useful in situations where risk assessment is difficult due to strong seasonal and spatial variation in risk variables, such as in Arctic regions. With progressive thinning of the ozone layer, the ability of some but not other organisms to adjust protection against UV radiation may lead to counter-intuitive, large-scale alterations in freshwater food webs.

Adaptation, Physiological↗
PubMed1999

Distribution patterns of marine bird digenean larvae in periwinkles along the southern coast of the Barents Sea.

An important component of the parasite fauna of seabirds in arctic regions are the flukes (Digena). Different species of digeneans have life cycles which may consist of 1 intermediate host and no free-living larval stages, 2 intermediate hosts and 1 free-living stage, or 2 intermediate hosts and 2 free-living larval stages. This study examined the distribution of such parasites in the intertidal zones of the southern coast of the Barents Sea (northwestern Russia and northern Norway) by investigating 2 species of periwinkles (Littorina saxatilis and L. obtusata) which are intermediate hosts of many species of digeneans. A total of 26,020 snails from 134 sampling stations were collected. The study area was divided into 5 regions, and the number of species, frequency of occurrence and prevalence of different digenean species and groups of species (depending on life cycle complexity) were compared among these regions, statistically controlling for environmental exposure. We found 14 species of digeneans, of which 13 have marine birds as final hosts. The number of species per sampling station increased westwards, and was higher on the Norwegian coast than on the Russian coast. The frequency of occurrence of digeneans with more than 1 intermediate host increased westwards, making up a larger proportion of the digeneans among infected snails. This was significant in L. saxatilis. The prevalence of different species showed the same pattern, and significantly more snails of both species were infected with digeneans with complicated life cycles in the western regions. In L. saxatilis, environmental exposure had a statistically significant effect on the distribution of the most common digenean species. This was less obvious in L. obtusata. The causes of changing species composition between regions are probably (1) the harsh climate in the eastern part of the study area reducing the probability of successful transmission of digeneans with complicated life cycles, and (2) the distribution of different final hosts.

Animals↗
PubMed1995

[Genetic structure and origin of the tetraploid toad Bufo danatensis Pisanetz, 1978 (Amphibia, Bufonidae) of Central Asia. Differentiation of geographic forms and genetic relationship between diploid and tetraploid species].

A hierarchical system, consisting of several levels of genetic divergence, is formed by distribution of genetic distances between diploid taxa of the green toad species complex (subspecies Bufo viridis viridis--B. v. turanensis and species B. viridis--B. sp.) and taxa representing western (B. viridis s.l.) and eastern (B. raddei) Pale-arctic regions. Formally, genetic differentiation of the tetraploid toad B. danatensis from the parapatric diploid species reaches the species level. Genetic diversity of the tetraploid species is more than twofold higher than the total diversity of two modern diploid species. This suggests that B. danatensis was formed with the participation of other unknown species in the past. The polyploid species B. danatensis is assumed to have originated by hybridization of two species groups that arose approximately 2.6 million years ago in Mediterranean and Central Asian regions of the western Palearctic. The genetic heterogeneity of geographical populations of the polyploid species indicates its polyphiletic origin. The heterogeneity range suggests that formation of the tetraploid species continued for a very long period (about 1 million years).

Animals↗
PubMed2004

Feasibility of Dual-Energy X-ray Absorptiometry in Arctic field studies.

BACKGROUND: Bone strength decreases with age. Bone mineral density (BMD) is a measure of bone strength. Data on BMD in present-day Inuit are limited, and data on circumpolar populations using Dual Energy X-ray Absorptiometry (DEXA scanning) are lacking. OBJECTIVES: Our aims were to validate DEXA scanning for use in field studies in the Arctic region and to obtain data on BMD in Greenland Inuit. METHODS: We measured BMD in 52 healthy Inuit living in Ilulissat and Saqqaq in North Greenland using a portable peripheral DEXA scanner. The measurement sites were forearms and calcaneal bones. Two measurements were performed at both radii and both calcanei. Triplicate measurements were performed in eleven Inuit. RESULTS: The portable scanner fitted into a standard bag suitable for transportation in the arctic winter. Imprecision was well within 2% for all calibrations. CV% were 0.16% to 1.79% in the forearms and 0.38% to 1.53% in the heels. The overall CV% was 1.09% in forearm and 1.01% in heel. Mean BMD in men was 0.569 g/cm2 in forearms and 0.542 in heel. In women it was 0.479 in forearms and 0.468 in heel. CONCLUSION: DEXA scanning is a feasible, reliable and comfortable method in rural Greenland. BMD values are now available for Greenland Inuit.

Absorptiometry, Photon↗
PubMed1992

Thyroid hormone changes during military field operations: effects of cold exposure in the Arctic.

This study examined the effect of prolonged physical activity in a cold environment upon circulating thyroid hormone levels. A secondary focus of the study involved the role of nocturnal habitat upon the thyroidal responses to the physical activity and cold exposure. Military personnel exposed to 10 d of field-based operations in the arctic region of Norway were studied. Blood samples were collected before (day 1), and at days 5 and 10 of the operations. Levels of total T4, free T4, total T3, free T3, and thyroid binding globulin were assessed in all blood samples. The results indicated considerable, significant (p less than 0.05) decreases in total thyroid hormone levels, while relative increases of free fractions of the hormones occur with the 10-d operations in the Arctic. However, no significant influence on thyroidal responses were observed due to the nocturnal habitat that the subjects lived in. The hormonal alterations noted are possibly brought about by the combined effects of physical activity and cold exposure acting synergistically to alter thyroid physiology (e.g., most likely the protein carrier binding affinity).

Adult↗
PubMed1989

No evidence for true HTLV-I or HIV-1 antibodies in Finnish Lapps.

Previous seroepidemiologic studies have suggested that in addition to certain subtropical and tropical parts of the world, human T cell leukemia virus type I (HTLV-I) may be endemic in the arctic regions, too. We studied 111 sera collected from original inhabitants of Finnish Lapland with ELISA and Western blot analysis for antibodies to HTLV-I and human immunodeficiency virus type 1 (HIV-1). No true positive sera for either virus were found in the confirmatory Western blot assays, albeit 6 and 2%, respectively, were positive in the screening ELISA assays. Despite the small sample size this survey does not support the hypothesis that HTLV-I would be endemic in the Arctic.

Arctic Regions↗
PubMed1992

Accidents in the Arctic. A psychological point of view.

The aim of this paper is to discuss the influence of arctic conditions on the occurrence of accidents especially from the point of view of the interaction between environment, activity and man. Special attention is paid to risk assessment, risk taking and risk compensation. According to the danger factor theory frostbites should be extremely common in arctic regions, but in reality serious frostbites appear rarely in accident statistics. This finding supports the interactive accident theories. Instead cold can be a contributing factor in accident and injury causation and the effect of cold is most often indirect. Frostbites can occur e.g. as a result of an accident, losing one's way because of darkness, snow storm etc., wet clothes, unexpected temperature changes, disease attack, alcohol-induced reasons such as immobility or excess risk taking etc. Temperatures below and above +20 degrees C increase unsafe behavior. In the Arctic it is impossible to remove all the potentially dangerous factors, because many typical features of working and living conditions are regulated by natural forces, the seasons etc. This makes accurate risk assessment and prediction especially important in accident prevention. If the person does not recognize the situations in which the risk factors exist, he/she cannot implement precautionary steps at the right moment and hence cannot avoid risks. Moreover, if better and safer machines, equipment and tools get people to take greater risks, the accident situation can even become worse.

Accident Prevention↗
PubMed2004

The Yana RHS site: humans in the Arctic before the last glacial maximum.

A newly discovered Paleolithic site on the Yana River, Siberia, at 71 degrees N, lies well above the Arctic circle and dates to 27,000 radiocarbon years before present, during glacial times. This age is twice that of other known human occupations in any Arctic region. Artifacts at the site include a rare rhinoceros foreshaft, other mammoth foreshafts, and a wide variety of tools and flakes. This site shows that people adapted to this harsh, high-latitude, Late Pleistocene environment much earlier than previously thought.

Animals↗