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At least 55 records · Page 3Linked to original sources
PubMed2000

Respiration during snow burial using an artificial air pocket.

CONTEXT: Asphyxia is the most common cause of death after avalanche burial. A device that allows a person to breathe air contained in snow by diverting expired carbon dioxide (CO2) away from a 500-cm3 artificial inspiratory air pocket may improve chances of survival in avalanche burial. OBJECTIVE: To determine the duration of adequate oxygenation and ventilation during burial in dense snow while breathing with vs without the artificial air pocket device. DESIGN: Field study of physiologic respiratory measures during snow burial with and without the device from December 1998 to March 1999. Study burials were terminated at the subject's request, when oxygen saturation as measured by pulse oximetry (SpO2) dropped to less than 84%, or after 60 minutes elapsed. SETTING: Mountainous outdoor site at 2385 m elevation, with an average barometric pressure of 573 mm Hg. PARTICIPANTS: Six male and 2 female volunteers (mean age, 34.6 years; range, 28-39 years). MAIN OUTCOME MEASURES: Burial time, SpO2, partial pressure of end-tidal CO2 (ETCO2), partial pressure of inspiratory CO2 (PICO2), respiratory rate, and heart rate at baseline (in open atmosphere) and during snow burial while breathing with the device and without the device but with a 500-cm3 air pocket in the snow. RESULTS: Mean burial time was 58 minutes (range, 45-60 minutes) with the device and 10 minutes (range, 5-14 minutes) without it (P=.001). A mean baseline SpO2 of 96% (range, 90%-99%) decreased to 90% (range, 77%-96%) in those buried with the device (P=.01) and to 84% (range, 79%-92%) in the control burials (P=.02). Only 1 subject buried with the device, but 6 control subjects buried without the device, decreased SpO2 to less than 88% (P=.005). A mean baseline ETCO2 of 32 mm Hg (range, 27-38 mm Hg) increased to 45 mm Hg (range, 32-53 mm Hg) in the burials with the device (P=.02) and to 54 mm Hg (range, 44-63 mm Hg) in the control burials (P=.02). A mean baseline PICO2 of 2 mm Hg (range, 0-3 mm Hg) increased to 32 mm Hg (range, 20-44 mm Hg) in the burials with the device (P=.01) and to 44 mm Hg (range, 37-50 mm Hg) in the control burials (P=.02). Respiratory and heart rates did not change in burials with the device but significantly increased in control burials. CONCLUSIONS: In our study, although hypercapnia developed, breathing with the device during snow burial considerably extended duration of adequate oxygenation compared with breathing with an air pocket in the snow. Further study will be needed to determine whether the device improves survival during avalanche burial.

Adult↗
PubMed2001

Cartographic modelling of aerotechnogenic pollution in snow cover in the landscapes of the Kola Peninsula.

The goal of this work was to develop computational techniques for sulphates, nickel and copper accumulation in the snow in the local pollution zone. The main task was to reveal the peculiarities of formation and pollution of snow cover on the region with complex cross-relief. A digital cartographic model of aerotechnogenic pollution of snow cover in the landscapes of the local zone has been developed, based on five-year experimental data. Data regarding annual emissions from the industrial complex, information about distribution of wind and the sum of precipitation from meteostation "Nikel" for the winter period, allowed the model to ensure: * material presentation in the form of maps of water capacity and accumulation of sulphates, nickel and copper in the snow over any winter period in retrospective; * calculation of water capacity and accumulation of pollutants for watersheds and other natural-territorial complexes; * solution of the opposite problem about the determination of the emissions of sulphates, nickel and copper from the enterprise by measuring snow pollution in datum points. The model can be used in other northern regions of the Russian Federation with similar physical-geographical and climatic conditions. The relationships between the sum of precipitation and water capacity in the landscapes of the same type and also the relationships between pollution content in snow and relief, pollution content in snow and distance from the source of emissions, were used as the basis for the model.

Copper↗
PubMed2003

Hypoxia and hypercapnia during respiration into an artificial air pocket in snow: implications for avalanche survival.

Snow avalanche case reports have documented the survival of skiers apparently without permanent hypoxic sequelae, after prolonged complete burial despite there being only a small air pocket on extrication. We investigated the underlying pathophysiological changes in a prospective, randomised 2 x 2 crossover study in 12 volunteers (28 tests) breathing into an artificial air pocket (1- or 2-l volume) in snow. Peripheral SpO(2), ETCO(2), arterialised capillary blood variables, air pocket O(2) and CO(2), snow density, and snow conditions at the inner surface of the air pocket were determined. SpO(2) decreased from a median of 99% (93-100%) to 88% (71-94%; P<0.001) within 4 min of breathing into the air pocket; the reduction was greater at 1 l, than 2 l, volume air pocket (P=0.013, intention to treat P=0.003) and correlated to snow density (r=0.50, P=0.021, partial correlation coefficient). ETCO(2) rose simultaneously from median 5.07 kPa (3.47-6.93 kPa) to 6.8 kPa (5.87-8.27 kPa; P<0.001), with consequent respiratory acidosis. Despite premature interruption due to hypoxia (SpO(2)</=75%) in 17 of 28 tests (61%), a respiratory steady state prevailed in five tests until protocol completion (30 min). We conclude that the degree of hypoxia following avalanche burial is dependent on air pocket volume, snow density and unknown individual personal characteristics, yet long-term survival is possible with only a small air pocket. Hence, the definition of an air pocket, "any space surrounding mouth and nose with the proviso of free air passages" is validated as the main criterion for triage and management of avalanche victims. Our experimental model will facilitate evaluating the interrelation between volume and inner surface area of an air pocket for survival of avalanche victims, whilst the present findings have laid the basis for future investigation of possible interactions between hypoxia, hypercapnia, and hypothermia (triple H syndrome) in snow burial.

Accidents↗
PubMed2002

Influence of ice and snow covers on the UV exposure of terrestrial microbial communities: dosimetric studies.

Bacillus subtilis spore biological dosimeters and electronic dosimeters were used to investigate the exposure of terrestrial microbial communities in micro-habitats covered by snow and ice in Antarctica. The melting of snow covers of between 5- and 15-cm thickness, depending on age and heterogeneity, could increase B. subtilis spore inactivation by up to an order of magnitude, a relative increase twice that caused by a 50% ozone depletion. Within the snow-pack at depths of less than approximately 3 cm snow algae could receive two to three times the DNA-weighted irradiance they would receive on bare ground. At the edge of the snow-pack, warming of low albedo soils resulted in the formation of overhangs that provided transient UV protection to thawed and growing microbial communities on the soils underneath. In shallow aquatic habitats, thin layers of heterogeneous ice of a few millimetres thickness were found to reduce DNA-weighted irradiances by up to 55% compared to full-sky values with equivalent DNA-weighted diffuse attenuation coefficients (K(DNA)) of >200 m(-1). A 2-mm snow-encrusted ice cover on a pond was equivalent to 10 cm of ice on a perennially ice covered lake. Ice covers also had the effect of stabilizing the UV exposure, which was often subject to rapid variations of up to 33% of the mean value caused by wind-rippling of the water surface. These data show that changing ice and snow covers cause relative changes in microbial UV exposure at least as great as those caused by changing ozone column abundance.

Antarctic Regions↗
PubMed2004

Simulating the influence of snow on the fate of organic compounds.

Snow scavenging, a seasonal snowpack, and a dynamic water balance are incorporated in a non-steady-state generic multimedia fate model in order to investigate the effect of snow on the magnitude and temporal variability of organic contaminant concentrations in various environmental media. Efficient scavenging of large nonpolar organic vapors and particle-bound organic chemicals by snow can lead to reduced wintertime air concentrations and incorporation in the snowpack. The snow cover functions as a temporary storage reservoir that releases contaminants accumulating over the winter during a short melt period, resulting in temporarily elevated concentrations in air, water, and soil. The intensity of these peaks increases with the length of the snow accumulation period. Organic chemicals of sufficient volatility (log KOA < 9; e.g., light polychlorinated biphenyls) can volatilize from the snowpack, resulting in springtime concentration maxima in the atmosphere. The behavior of fairly water-soluble chemicals during snowmelt depends on their relative affinity for the newly formed liquid water phase and the rapidly diminishing ice surface-quantitatively expressed by their interface-water partition coefficient (KIW). Chemicals with a preference for the dissolved phase (low KIW; e.g., pentachlorophenol) can become enriched in the first meltwater fractions and experience a temporary concentration peak in lakes and rivers. Organic chemicals that are neither volatile enough to evaporate from the snowpack nor sufficiently water soluble to dissolve in the meltwater (e.g., polybrominated diphenyl ethers) sorb to the particles in the snowpack. These particles may be sufficiently contaminated to constitute the major input route to the terrestrial environment upon release during snowmelt. Because wintertime deposition to the snowpack may be higher than to a non-snow covered surface, this can result in higher soil concentrations of persistent organic contaminants in the long term. The potential ecotoxicological significance of peak exposures demands a better understanding of the role of snow in the fate of organic contaminants.

Environmental Monitoring↗
PubMed2003

Coagulation and fibrinolytic responses to manual versus automated snow removal.

PURPOSE: The purpose of this study was to assess coagulation and fibrinolytic responses to snow removal. METHODS: Thirteen healthy male subjects (age = 26 +/- 5 yr, height = 179.0 +/- 7.0 cm, weight = 78.7 +/- 16.1 kg, .VO2max = 54.7 +/- 8.9 mL.kg-1.min-1) underwent maximal treadmill stress testing (TM), 10 min of snow shoveling (SS), and 10 min of snow removal using an automated snow thrower (ST). Blood was collected immediately before and after each test and analyzed for von Willebrand Factor antigen (vWF:ag), tissue plasminogen activator (tPA) antigen, and plasminogen activator inhibitor-1 (PAI-1) activity. Data were analyzed using a two-factor repeated-measures analysis of variance. RESULTS: vWF:ag significantly increased during TM (84.7 +/- 21.7% normal preexercise, 149.0 +/- 45.6% normal postexercise) but not SS or ST. TM resulted in significant increases in tPA antigen (6.54 +/- 2.76 ng.mL-1 preexercise, 21.39 +/- 10.56 ng.mL-1 postexercise) and both SS and TM caused significant reductions in PAI-1 activity (SS = 15.1 +/- 3.8 AU.mL-1 preexercise, 13.2 +/- 4.3 AU.mL-1 postexercise; TM = 15.3 +/- 3.6 AU.mL-1 preexercise, 10.5 +/- 5.3 AU.mL-1 postexercise). Postexercise PAI-1 activity was significantly lower for TM versus SS. tPA antigen was unchanged after SS and ST, and PAI-1 activity was unchanged after ST. CONCLUSION: vWF:ag is unchanged after self-paced snow shoveling and automated snow removal in young, healthy males. Snow shoveling acutely increases fibrinolytic potential in this population, although not to the degree observed after maximal treadmill exercise.

Adult↗
PubMedDate not supplied

Influence of manure application on surface energy and snow cover: field experiments.

Application of manure to frozen and/or snow-covered soils of high-latitude, continental climate regions is associated with enhanced P losses to surface water bodies, but the practice is an essential part of most animal farming systems in these regions. Field experiments of the fates of winter-applied manure P are so difficult as to make them essentially impractical, so a mechanistic, modeling approach is required. Central to a mechanistic understanding of manure P snow-melt runoff is knowledge of snowpack disappearance (ablation) as affected by manure application. The objective of this study was to learn how solid manure applied to snow-covered fields modulates the surface energy balance and thereby snow cover ablation. Manure landspreading experiments were conducted in Arlington, WI during the winters of 1998 and 1999. Solid dairy manure was applied on top of snow at a rate of 70 Mg ha(-1) in 1998, and at 45 and 100 Mg ha(-1) in 1999. Results showed that the manure retarded melt, in proportion to the rate applied. The low-albedo manure increased absorption of shortwave radiation compared with snow, but this extra energy was lost in longwave radiation and turbulent flux of sensible and latent heat. These losses result in significant attenuation of melt peaks, retarding snowmelt. Lower snowmelt rates beneath manure may allow more infiltration of meltwater compared with bare snow. This infiltration and attenuated snowmelt runoff may partially mitigate the enhanced likelihood of P runoff from unincorporated winter-spread manure.

Climate↗
PubMed2006

Polycyclic aromatic hydrocarbons and metals in snow along a highway.

Snow quality and its variations due to distance from the road were studied. Also, how the snow quality changes over time during the melting period was discussed. Snow samples were collected at three occasions during the winter of 2004. The samples were taken along a highway in the Luleå region, Sweden, with an average daily traffic load of 9200 vehicles. Snow samples were taken perpendicular to the road and at different distances. The snow samples were analysed for metals and polycyclic aromatic hydrocarbons (PAH). Also, weather parameters such as temperature, precipitation, and wind speed and wind direction were measured. The highest total metal and PAH concentrations were found at the sample site closest to the road and at the end of the season. Before the melting period started, 42-57% of the total amount of metals and PAH were found in the first 1 m of the snow pack. This information could be valuable when one is discussing how to achieve sustainable snow-handling management.

Environmental Monitoring↗
PubMedDate not supplied

[Relation of the snow cover to the structure of vegatation in the alpine communities of the eastern Tsinghai-Tibet Plateau].

The type of snow cover considerably influences the sctructure of vegetation and production-related processes in alpine communities of diverse regions. The relation of snow cover thickness to the structure of apline plant communities in the eastern Tsinghai-Tibet Plateau (Sichuan, People's Republic of China) was studied by analyzing the vegetation in 251 sample areas grouped in five transects along the gradient of mesotopographic conditions and wintertime snow cover thickness. Considerable differentiation of plant communities related to snow cover thickness in revealed along the line from the northern to the southern slope. It is shown that the influence of snow cover on the distribution of particular plant species is significantly greater than the influence of soil properties (pH, content of humus, total phosphorus, potassium, and ammonia nitrogen in the upper strata of soil). Among the 56 herbaceous plant species and 7 shrub species studied, 52 herbaceous and all the 7 shrub species showed significant (P < 0.05) correlation (positive or negative) to snow cover thickness. Snow cover thickness appeared also significantly correlated to a number of soil properties: soil thickness, content of water, total phosphorus, and humus. But, in contrast to the alpine communities of the Caucasus and the Alps, no considerable acidification of the soil under snowflakes, due to perpetual removal of cations by melt water, was observed.

Adaptation, Physiological↗
PubMed2005

Polychlorinated naphthalenes in air and snow in the Norwegian Arctic: a local source or an Eastern Arctic phenomenon?

PCNs were measured in air and snow during separate field campaigns at Ny-Alesund (April 2001) and Tromsø (February/March 2003) in the Norwegian Arctic. Air concentrations ranged from 27 to 48 and 9 to 47 pg sigmaPCN m(-3) for Ny-Alesund (n=6) and Tromsø (n=10), respectively. These concentrations (including the tri-chlorinated naphthalenes) greatly exceeded concentrations previously measured in the Canadian Arctic, but did fall within the upper range of concentrations observed over the eastern Arctic Ocean and regional seas. Local sources appear to be affecting concentrations observed at both sites, with the presence of several hexa-chlorinated naphthalenes at Tromsø probably attributed to local/regional sources. Use of air mass back trajectories at Tromsø revealed that background air concentrations in the Norwegian Arctic are likely to range between <9 and 20 pg sigmaPCN m(-3) and that contemporary concentrations derived close to potential sources (i.e. arctic towns) may equal or exceed those of PCBs. The mean concentration in surface snow was 350 and 240 pg sigmaPCN L(-1) (meltwater) (or 0.014 and 0.01 pg g(-1) (snow)) at Ny-Alesund and Tromsø, respectively. The wide variation in concentrations observed between fresh snowfalls could be explained by different snow densities (as a surrogate of snow surface area), rather than attributed to varying air concentrations. A statistically significant inverse relationship was found between snow density and concentrations of tri- to penta-chlorinated homologues and compliments similar findings for the polychlorinated biphenyls (PCBs). This suggests that the vapour-sorbed quantity changes rapidly with snow ageing/compaction; with implications for the fate of these chemicals in the Arctic.

Journal Article↗
PubMed2002

Mercury speciation in the French seasonal snow cover.

Snow samples have been collected in the French Alps in 1998, 1999 and 2000 in order to measure both total Hg (HgT) and reactive Hg (HgR). Concentrations of HgT were between 13 and 130 pg g(-1) and HgR concentrations were below the detection limit (approximately 0.8 pg g(-1)). Hg speciation in snow was evaluated on the basis of ionic complexation equilibrium with chloride, hydroxide, oxalate. The pH of the snow was found to be an important parameter for Hg speciation. For pH values near 3, HgC2O4 is predominant in snow samples except for snow strongly influenced by anthropogenic sources (in which case HgCl2 predominates). When pH > 4, Hg(OH)2 and HgOHCl are predominant. These latter pH values are observed for precipitation not influenced by anthropogenic sources but more by soil erosion, e.g. Saharan dusts. The knowledge of Hgr speciation in snow is a key question for understanding the mechanisms of transformation of these complexes in snow after precipitation.

Journal Article↗
PubMed1990

Fate of Ice Nucleation-Active Pseudomonas syringae Strains in Alpine Soils and Waters and in Synthetic Snow Samples.

The stability of the ice nucleation activity (INA) and viability of INA Pseudomonas syringae 31a, used as an ice nucleator in the manufacture of synthetic snow, was determined in snow. The viability of P. syringae 1-2b, a rifampin-resistant mutant selected from strain 31a to improve recovery from test samples, was determined in laboratory tests of three alpine soil and water samples from three different sources. Snow samples were exposed to environmental conditions or held in darkness at -20 degrees C. Samples of soil and water were maintained in darkness at 0, 7.5, or 15 degrees C. Parent strain 31a INA decreased significantly (>99.0%) in snow exposed to sunlight and freeze-thaw, while the INA of the cell population in snow held in darkness at -20 degrees C remained essentially unchanged. No viable strain 31a was detected in snow exposed to the environment after 7 days, while the viability of strain 31a in snow held in darkness at -20 degrees C decreased to <3% of the original inoculation at the test conclusion. Mutant strain 1-2b viability was undetectable or had decreased significantly 19 days postinoculation in soil samples held at 0 or 15 degrees C. In contrast, 1-2b viability remained detectable at low levels for the duration of the test in soils held at 7.5 degrees C. The 1-2b population demonstrated a significantly longer half-life in peatlike soil than in the loam soils tested. The rate of decrease in 1-2b viability was essentially the same in the three alpine water samples tested with respect to water temperature and sample location.

Journal Article↗
PubMed2004

A report of dangerously high carbon monoxide levels within the passenger compartment of a snow-obstructed vehicle.

BACKGROUND: We sought to determine how quickly carbon monoxide would accumulate in the passenger compartment of a snow-obstructed vehicle. METHODS: A 1992 sedan was buried in snow to the level of the undercarriage, the ignition was then engaged and carbon monoxide levels recorded at 2.5-minute intervals. The primary outcome was the time at which a lethal carbon monoxide level was detected. Six trials were conducted: windows closed; windows open one inch; windows open 6 inches; windows closed and tailpipe swept clear of snow; windows closed and one cubic foot of snow removed around tailpipe; windows closed and tailpipe completely cleared of snow to ground level in a path 12 inches wide. RESULTS: Lethal levels of carbon monoxide occurred within 2.5 minutes in the vehicle when the windows were closed, within 5 minutes when the widows were opened one inch, and within 7.5 minutes when the widows were opened six inches. Dangerously high levels of carbon monoxide were detected within the vehicle when the tailpipe had been swept clear of snow and when a one cubic foot area had been cleared around the tailpipe. When the tailpipe was completely unobstructed the carbon monoxide level was zero. CONCLUSIONS: Lethal levels of carbon monoxide occurred within minutes in this snow-obstructed vehicle.

Journal Article↗
PubMed1993

Serum concentrations of oestradiol and progesterone and frequency of sexual behaviour during the normal oestrous cycle in the snow leopard (Panthera uncia).

Serum oestradiol and progesterone concentrations were measured at weekly intervals for six months, and correlated with daily behavioural observations in two adult female snow leopards (Panthera uncia). Three oestradiol peaks (> 21 pg ml-1; interval 3.6 weeks) were identified in a snow leopardess housed alone (two more were probably missed because of the weekly sampling schedule), and three oestradiol peaks were identified in a snow leopardess housed with a male as a breeding pair (interval 6 weeks). Daily frequencies of feline reproductive behaviour averaged 1.77 observations per observation period during weeks of high oestradiol and 0.62 during weeks of low oestradiol. Progesterone concentrations did not rise above baseline values (< 2 ng ml-1) in the isolated animal, but 6 weeks of high progesterone concentrations (4.9-38.8 ng ml-1) was recorded in the paired snow leopardess following mating. No offspring were produced. Snow leopards were observed daily for an additional 4.5 years. Sexual behaviour peaks could be clearly identified from December through April, and average daily sexual behaviour scores were higher during these months than during the rest of the year. Intervals between sexual behaviour peaks for the isolated snow leopardess averaged 3.03 weeks. The sexual behaviour of the paired snow leopards decreased for 8-9 weeks following mating when no offspring were produced, and decreased for 13 weeks in one year when a single cub was born.

Animals↗
PubMed2003

Collecting, shipping, storing, and imaging snow crystals and ice grains with low-temperature scanning electron microscopy.

Methods to collect, transport, and store samples of snow and ice have been developed that enable detailed observations of these samples with a technique known as low-temperature scanning electron microscopy (LTSEM). This technique increases the resolution and ease with which samples of snow and ice can be observed, studied, and photographed. Samples are easily collected in the field and have been shipped to the electron microscopy laboratory by common air carrier from distances as far as 5,000 miles. Delicate specimens of snow crystals and ice grains survive the shipment procedures and have been stored for as long as 3 years without undergoing any structural changes. The samples are not subjected to the melting or sublimation artifacts. LTSEM allows individual crystals to be observed for several hours with no detectable changes. Furthermore, the instrument permits recording of photographs containing the parallax information necessary for three-dimensional imaging of the true shapes of snowflakes, snow crystals, snow clusters, ice grains, and interspersed air spaces. This study presents detailed descriptions of the procedures that have been used successfully in the field and the laboratory to collect, ship, store, and image snow crystals and ice grains.

Cold Temperature↗
PubMed1988

Heavy metal concentrations in urban snow as an indicator of air pollution.

Manganese, Zn, Pb, Cu, Cr and Cd concentrations in snow collected in and around urban areas and from snow dumping stations in Hokkaido were determined by Zeeman-type atomic absorption spectrophotometry. We compared the heavy metal concentrations in the snow with background levels to see whether they could be used as an effective indicator of urban air pollution. The heavy metal concentrations in the snow clearly increased towards the center of the city of Sapporo; they were influenced by local pollution in the industrial area of the city and by the effect of the seasonal wind from the northwest. In the cities, we found the greatest influence on heavy metal concentrations was air pollution caused by industrial activities. The elemental concentrations in urban snow were from several to tens of times higher than background levels. The mean concentrations of the elements studied were in the order Mn greater than Zn greater than Pb greater than Cu greater than Cr greater than Cd, the same as in water except for Pb. We propose that data on trace metal concentrations in snow are a reliable guide to the degree of air pollution, and can be used as a simple and effective indicator of urban air pollution.

Air Pollution↗
PubMed2004

Investigating the occurrence of persistent organic pollutants (POPs) in the arctic: their atmospheric behaviour and interaction with the seasonal snow pack.

POPs in the Arctic are the focus of international concern due to their occurrence and accumulation in Arctic food webs. This paper presents an overview of the major pathways into the Arctic and details contemporary studies that have focused on the occurrence and transfer of POPs between the major Arctic compartments, highlighting areas where there is a lack of quantitative information. The behaviour of these chemicals in the Arctic atmosphere is scrutinised with respect to long-term trends and seasonal behaviour. Subtle differences between the PCBs and OC pesticides are demonstrated and related to sources outside of the Arctic as well as environmental processes within the Arctic. Unlike temperate regions, contaminant fate is strongly affected by the presence of snow and ice. A description of the high Arctic snow pack is given and the physical characteristics that determine chemical fate, namely the specific surface area of snow and wind driven ventilation, are discussed. Using a well-characterised fresh snow event observed at Alert (Canadian high Arctic) [Atmos. Environ. 36(2002) 2767] the flux of gamma-HCH out of the snow is predicted following snow ageing. Under conditions of wind (10 m/s) it is estimated that approximately 75% of the chemical may be re-emitted to the atmosphere within 24 h following snowfall, compared with just approximately 5% under conditions of no wind. The implications of this are raised and areas of further research suggested.

Air Pollutants↗
PubMed2006

Scavenging of gaseous mercury by acidic snow at Kuujjuarapik, Northern Québec.

One fate of gaseous elemental mercury (GEM) in the Arctic has been identified as gas phase oxidation by halogen-containing radicals, leading to abrupt atmospheric mercury depletion concurrent with ozone depletion. Rapid deposition of oxidized mercury leads to snow enrichment in mercury. In this report, we describe experiments that demonstrate the ability of snow to directly scavenge atmospheric mercury. The study was conducted at Kuujjuarapik, Québec, Canada (latitude 55 degrees 17'N). A mercury depletion event (MDE) caused the mercury concentration in the surface snow of the coastal snowpack to double, from (9.4+/-2.0) to (19.2+/-1.7) ng/L. Independent of the MDE, mercury concentrations increased five-fold, from (10.0+/-0.1) to (51.4+/-6.0) ng/L, upon spiking the snow with 500 microM hydrogen peroxide under solar irradiation. Total organic carbon in the spiked irradiated snow samples also decreased, consistent with the formation of strongly oxidizing species. The role of the snowpack in releasing GEM to the atmosphere has been reported; these findings suggest that snow may also play a role in enhancing deposition of mercury.

Air Pollutants↗