Ski wax use contributes to environmental contamination by per- and polyfluoroalkyl substances

Per- and polyfluoroalkyl substances (PFAS) are used in a wide variety of consumer products, including ski waxes, and are widespread persistent and hazardous environmental contaminants. We examined the environmental impact of ski wax use at an outdoor recreation area with significant cross-country ski activity by measuring PFAS levels in melted snow, soil and water following a collegiate ski race. We found extremely high levels of long- and short-chain PFAS (C4-C14) contamination in snow at the race start line (∑[PFAS] 7600-10,700 ng/L), with the longer-chain analytes (C10-C14) predominating. The complement of 14 PFAS detected in snow matched what has been found in ski wax. This snow contamination was greatly reduced at a point 3.9 km into the race. Soil at the start line contained the four most predominant PFAS in snow at a mean individual concentration of 2.81 ng/g dry weight. Control soil contained only perfluorooctane sulfonic acid (PFOS), not found in other soil samples, at a concentration of 2.80 ng/g. Shallow groundwater from an on-site well contained only the shorter-chain PFAS (C4-C8), with a mean individual concentration of 4.95 ng/L. Our results suggest that ski wax use, from which fluorocarbons abrade at very high levels onto snow during a ski race, are the main source of PFAS contamination at our site. Regulation of ski wax use is warranted to reduce PFAS pollution.

Plasma Vitellogenin Reveals Potential Seasonal Estrogenicity in Fish from On-Site Wastewater Treatment Systems in Semi-Arid Streams Influenced by Snowmelt

Effluents from on-site wastewater treatment systems can influence surface water quality, particularly when infrastructure is aging, malfunctioning, and improperly installed. Municipal wastewater often contains chemical compounds that can lead to adverse biological effects, such as reproductive impairment, in organisms that are chronically exposed. A significant number of these compounds are endocrine-disrupting chemicals. Water quality influences of on-site systems are poorly studied in semi-arid regions where instream flows are seasonally dependent on snowmelt, and when instream dilution of wastewater effluents is minimal during other times of the year. Here we examined surface water estrogenicity in low order tributaries of two unique semi-arid streams with on-site wastewater treatment systems, for which seasonal instream flow fluctuations occur in Park City, UT, USA. Water samples were collected from a total of five locations along two lotic systems downstream from active on-site treatment systems. Samples were extracted for targeted chemical analyses and to perform in vivo and in vitro bioassays with juvenile rainbow trout. Estrogenic activity was measured by quantifying the concentration and expression of vitellogenin (VTG) in plasma and liver, respectively. Plasma VTG presented elevated levels in fish exposed to water samples collected at the two sites in close proximity to on-site systems and during seasons with low stream discharge, though the levels observed did not suggest severe endocrine disruption. However, long-term exposure to these surface water could compromise the fish populations. While the sensitivity of in vitro bioassays was low and targeted chemical analyses did not identify causative compounds, the use of complementary lines of evidence (e.g., in vivo biological models) was advantageous in identifying estrogenic activity in waters influenced by effluents from on-site wastewater systems.

Isotopic composition and hydrogeochemistry of a periglacial Andean catchment and its relevance in the knowledge of water resources in mountainous areas

Glacial and periglacial basins contain the largest reserves of fresh water in the world. These areas are extremely sensitive to global warming and climate change. The dry Andes of South America are characterized by large periglacial areas. This study focuses on the water isotopic composition and hydrochemistry of a typical periglacial environment of the Andes, in the Vallecitos catchment (2400-5500 m a.s.l.), Cordillera Frontal, Argentina. Detailed fieldwork was conducted between 2013 and 2017 with 240 samples collected for major ions and physicochemical parameters, and 67 samples analysed for ²H and ¹⁸O. The chemical composition of precipitation is typical Ca-HCO₃, while streams and groundwaters are Ca-MgSO₄ type. The isotope content of precipitation shows a wide dispersion. The snow samples are in general more depleted than the rainfall. Some springs vary their composition seasonally, associated to the melting of perennial snow patches. In general, all samples from the upper basin present depleted isotope contents related to recharge at higher altitudes, whereas samples from the lower basin show more enriched values. Intermediate compositions reflect the melting of snow and degrading ice-rich permafrost. These results will give a better understanding of the dynamics of water to manage water resources.

First snow, glacier and groundwater contribution quantification in the upper Mendoza River basin using stable water isotopes

The Mendoza River streamflow, South America (∼32 °S), derives almost exclusively from winter snow precipitation falling in the Andes. Almost 70% of the water feeding the river originates in the Cordillera Principal geological province. In addition to the snow that precipitates in this area, there are 951 cryoforms providing meltwater to the upper catchment. Given the high inter-annual variability of snowfall and the megadrought affecting the region since 2010, it is crucial to quantify the contribution from different water sources buffering the Mendoza River runoff. Combining instrumental records of streamflow from glaciers and rivers, meteorological data, remote sensing of snow-covered areas and ionic and stable isotope analysis of different water sources, this study attempts to understand the hydrological contribution of different water sources to the basin. We demonstrated for the first time the relevance of different water sources in addition to snow in a dry period. During the melting season, 65% of the streamwaters originated from the glaciers (i.e. 50 and 15% from glaciers and rock glaciers, respectively), representing a higher proportion compared to snowmelt (17%). Groundwater input showed relatively large contributions, averaging 18%. This work offers information to develop adaptation strategies for future climate change scenarios in the region.

Isotopic analysis of snow from Dome C indicates changes in the source of atmospheric lead over the last fifty years in East Antarctica

Lead (Pb) concentration and Pb isotope ratios have been determined in 109 snow pit samples collected at Dome C, on the East Antarctic Plateau, corresponding to the period 1971-2017. The Pb concentration was 8.2 ± 1.0 pg g^-1 (mean ± 95%-confidence interval), with a decreasing trend from the early 1990s (the median Pb concentration halved from 9.0 pg g^-1 in 1970-1980 to 4.4 pg g^-1 in 2010-2017). The ²⁰⁶Pb/²⁰⁷Pb and ²⁰⁸Pb/²⁰⁷Pb ratios were 2.419 ± 0.003 and 1.158 ± 0.003 (mean and 95%-confidence interval), respectively. The temporal variations of Pb isotopic composition from 1970 to mid-1990s reflect the changes in the consumption of Pb-enriched gasoline in the Southern Hemisphere, whereas the subsequent increase of the Pb isotope ratios is ascribed to a shift toward the natural isotopic signature. Accordingly, the anthropogenic Pb contribution decreased from (61 ± 3)% in 1980-1990 to (49 ± 10)% in 2010-2017. The measured ratios suggest that Australia has been a significant source of anthropogenic Pb to Antarctica, even in recent times. Differences and similarities among Pb content and isotopic composition in various sites across Antarctica have been displayed by principal component analysis, indicating that the altitude and the distance from the coast significantly affect the Pb content, while the Pb isotopic signatures are not influenced by these parameters.

Assessment of major ions and trace elements in snow: A case study across northeastern China, 2017-2018

A total of 60 snow samples from 16 sites across northeastern China were collected from December 2017 to March 2018. The snow samples were analyzed for pH value, major water-soluble ions (Cl^-, NO₃^-, SO₄^2-, Na⁺, NH₄⁺, K⁺, Ca²⁺, and Mg²⁺), and trace elements (Mn, Cr, Cd, Ni, Cu, Zn, Pb, As, and Fe). The results indicated that snow was slightly alkaline (mean pH value 7.54); Ca²⁺ and SO₄^2- were the major ions, contributing up to 33.87% and 22.72% of the major ions, respectively; Pb was the dominant element, contributing up to 62.84% of the trace elements. Both the concentration of major ions and trace elements peaked in the middle or later period of the entire snow season. Enrichment factor (EF) analysis indicated that ions (NO₃^-, NH₄⁺, and Ca²⁺) and trace elements (Pb, As, Cu, and Zn) were severely enriched by anthropogenic activities. Compared with previous studies, which sampled snow from the high altitude and latitude regions, the concentrations of most of the ions and trace elements in this study were found to be 1-3 and 1-4 orders of magnitude higher, respectively, indicating a threat to human health.

Transformation mechanism of ions on different waters in alpine region

The study investigates transformation mechanism of ions on different waters in Alpine region through analyzed the hydrochemical characteristics of the major ions of precipitation, glacier and snow meltwater, supra-permafrost water and river water in permafrost regions in the Tibetan Plateau under climate warming. The results showed that, The relation between recharge and discharge was the major ways for ionic transformation of each water body. Precipitation and glacier and snow meltwater are the main input sources for ionic transformation, and river water is the final output source. Different water bodies had different ionic concentrations and different hydrochemical types. However, different water bodies in different months (from June to September) also had different hydrochemical types. The water - rock interaction, reactions for ions, dilution effect and other effect for ions played an important role in the process of ion transformation. The increasing of temperature would lead to the accelerated melting of glaciers, permafrost and snow in the alpine regions, so the amount of supra-permafrost water and glacier and snow meltwater will increase, which leads to the increase of runoff. Meanwhile, the increase of temperature makes evaporation stronger. The strong of evaporation will accelerate the transformation of liquid water to gaseous water. Moreover, ion translation and water conversion are synchronous. Accordingly, ions are also accelerating transformation in the process of accelerated transformation of water body. Climate change is not only the main driving force for multiphase water transformation, but also the main driving force for the ion transformation of various water bodies.

Reliable Ultra Trace Analysis of Cd, U and Zn Concentrations in Greenland Snow and Ice by Using Ultraclean Methods for Contamination Control

This study presents ultraclean procedures used in the challenging task of determining trace elements at or below the pg/g concentration level encountered in Greenland snow and ice. In order to validate these ultraclean procedures, recent snowfall and Holocene ice from northwest Greenland were analyzed for Cd, U, and Zn concentrations. The total procedural blanks brought through the entire measurement procedure proved to be negligible, compared to trace element concentrations, measured in snow and ice samples. This validates the overall practicality of the proposed ultraclean procedures, thereby ensuring the reliable measurements of ultra-trace analysis. A comparison between our study and published data shows that improper procedures employed throughout all stages, from field sampling to analysis to elevate the concentrations by several orders of magnitude, relative to the reliable concentration ranges. The risk of contamination exposure for selected trace elements appears to increase in the order of U < As ≤ Pb < Cd < Zn. Reliable measurements of Cd, U, and Zn concentrations in snow and ice allowed us to interpret the data in terms of seasonal variations in the inputs of crustal and anthropogenic sources to Greenland ice sheet.

Source, contribution and microbial N-cycle of N-compounds in China fresh snow

The importance and contribution of nitrogen compounds and the related microbial nitrogen cycling processes in fresh snow are not well understood under the current research background. We collected fresh snow samples from 21 cities that 80% are from China during 2016 and 2017. Principal component analysis showed that SO₄^2- were in the first principal component, and N-compounds were the second. Furthermore, the main pollutant ions SO₄^2- and NO₃^- were from anthropogenic sources, and SO₄^2- contributed (61%) more to the pollution load than NO₃^- (29%), which were confirmed through a series of precipitation mechanism analysis. We selected five N-cycle processes (consist of oxidation and reduction processes) for molecular biology experiments, including Ammonia-oxidation process, Nitrite-oxidation process, Denitrification process, Anaerobic-ammoxidation process (Anammox) and Dissimilatory nitrate reduction to ammonium process (DNRA). Except ammonia-oxidizing archaeal (AOA) and bacterial (AOB) amoA genes (above 10⁷ copies g^-1), molecular assays of key functional genes in various nitrogen conversion processes showed a belowed detection limit number, and AOB abundance was always higher than AOA. The determination of the microbial transformation rate using the ¹⁵N-isotope tracer technique showed that the potential rate of five N-conversion processes was very low, which is basically consistent with the results from molecular biology studies. Taken together, our results illustrated that microbial nitrogen cycle processes are not the primary biological processes causing the pollution in China fresh snow.

Assessing the ecophysiological response of a mountain grassland community to ski slope management through isotopic composition

A scarce natural snow cover forces an increasing use of artificial snow on ski slopes and returns a small amount of snowmelt water available to plants outside the pistes at the beginning of the growing season. We tested if the use of artificial snow on the ski slopes and the decreased natural snow cover outside the ski slopes lead to changes in the leaf ecophysiology of dominant species in a ski area located in Northern Italy. Using carbon (¹³C/¹²C) and oxygen (¹⁸O/¹⁶O) stable isotope ratios in plant leaves, we estimated the intrinsic water use efficiency (iWUE) and we speculated about changes in photosynthesis and stomatal conductance. Furthermore, carbon and nitrogen concentration, pigments and dry matter content, and the specific area of leaves were measured. We found a higher iWUE of the plants on the ski slopes than outside, probably because the plants on the ski piste are exposed to a condition close to waterlogging that can lead them to regulate their stomata differently than the plants outside the pistes. This behaviour was observed particularly in Ranunculus acris and in Tussilago farfara, for these species the water surplus on the piste may have affected the plants' gas exchanges.

Atmospheric deposition of polychlorinated biphenyls to seasonal surface snow at four glacier sites on Svalbard, 2013-2014

During spring 2014 we collected annual surface snow from four glacial sites on Svalbard, an archipelago in the European Arctic. The sampling sites are 230 km apart from west to east, but are at varying elevations, affecting local atmospheric contaminant inputs. Samples were analyzed for 209 polychlorinated biphenyl (PCB) congeners. The western sites, Holtedahlfonna and Kongsvegen, had the highest ∑PCB flux (26.7 pg cm^-2 yr^-1 at Kongsvegen) while the lowest was at Lomonosovfonna, in central Svalbard (14.4 pg cm^-2 yr^-1). The greatest difference between sites was the trichlorobiphenyl homologue which was nearly four times greater at Kongsvegen than the eastern site at Austfonna. The most concentrated congeners at each site were PCB-52, 70 + 74, 95, 101, 110 comprising 32-39% of ∑PCB, similar to Clophen 40 which is comprised 27% of these congeners. Similar variance of these congeners in samples and Clophen 40 was verified by principal components analysis. Air mass back trajectories from likely source areas for all sites were similar, indicating no difference in frequency or distribution of PCB from long-distances, suggesting local PCB sources contributing to Kongsvegen. We found 2,3-DiCB (PCB-5) and 3,3'-DiCB (PCB-11) at all sites; neither was found in western commercial PCB mixtures. PCB-5 may be from the Russian PCB product "Trichlorobiphenyl" or is residue from production of pigment violet 23. PCB-11 may come from waste incineration in northern Europe containing various pigments. These results, in comparison to earlier data from Lomonosovfonna, suggest that PCB inputs are variable and are not declining over time.

Distribution of Policyclic aromatic hydrocarbons in a snow cover in the territory of Ivanovo city, Russia

The paper presents the results of a study of the content of 12 polyaromatic hydrocarbons (PAHs) in the snow cover of the city of Ivanovo (Russian Federation). It is shown that their average content exceeds the background level by 6.6 times, which made it possible to identify for which compounds the admission channels are associated with transboundary transport (naphthalene, pyrene, benz [b]fluorantin, benzo [a]pyrene and dibenz [a,h]anthracene), and for which with local emission sources (anthracene, phenanthrene, fluoranthene, chrysene, benz [k]fluorantin, and benzo [g,h,i]perylene). According to the known indicator ratios of the concentrations of PAHs, the main sources of release (pyrogenic and mixed) PAHs into the environment were estimated. The combination of experimental data in combination with factor analysis allowed identifying priority PAHs (naphthalene, fluoren, fluoranthene, benzo [a]pyrene and benzo [g,h,i]perylene), which should be included in the environmental monitoring programs of the region. Environmental risk assessments are given, which showed that the level of pollutant does not always adequately reflect the environmental impact for the territories. Thus, the contribution to the total PAH concentration of benz [b]fluorantin is only 9%, and to the amount of environmental risk - 51%. This must be taken into account in order to prioritize the control of individual components of PAHs in environmental objects.

Self-contamination from clothing in microplastics research

Self-contamination should not be underestimated when quantifying microplastics (MPs) in environmental matrices. Standardised and validated methodologies for MP sampling, extraction, and analysis are lacking. The various applications of plastics in our society have made them ubiquitous, even in clothing, rendering MP self-contamination inevitable. In the present study, we sampled lake sediment, snow, and ice, purposefully wearing red overalls composed of cotton; fibres from which we could quantify using Fourier-Transform Infrared Spectroscopy (FTIR), serving as an indication of possible self-contamination from clothes. The suitability of cotton as a representation of MP contamination was also evaluated. For all detected fibres, 25 ± 1%, 20 ± 7%, and 8 ± 6% for snow, ice, and sediment, respectively, originated from sampling attire. These findings demonstrate that self-contamination can play a significant role when quantifying MP pollution, highlighting that sampling conducted to date might have overestimated the presence of MP or even contaminated MP-free samples.

Microbial mercury methylation in the cryosphere: Progress and prospects

Mercury (Hg) is one of the most toxic heavy metals, and its cycle is mainly controlled by oxidation-reduction reactions carried out by photochemical or microbial process under suitable conditions. The deposition and accumulation of methylmercury (MeHg) in various ecosystems, including the cryospheric components such as snow, meltwater, glaciers, and ice sheet, and subsequently in the food chain pose serious health concerns for living beings. Unlike the abundance of knowledge about the processes of MeHg production over land and oceans, little is known about the sources and production/degradation rate of MeHg in cryosphere systems. In addition, processes controlling the concentration of Hg and MeHg in the cryosphere remains poorly understood, and filling this scientific gap has been challenging. Therefore, it is essential to study and review the deposition and accumulation by biological, physical, and chemical mechanisms involved in Hg methylation in the cryosphere. This review attempts to address knowledge gaps in understanding processes, especially biotic and abiotic, applicable for Hg methylation in the cryosphere. First, we focus on the variability in Hg concentration and mechanisms of Hg methylation, including physical, chemical, microbial, and biological processes, and transportation in the cryosphere. Then, we elaborate on the mechanism of redox reactions and biotic and abiotic factors controlling Hg methylation and biogeochemistry of Hg in the cryosphere. We also present possible mechanisms of Hg methylation with an emphasis on microbial transformation and molecular function to understand variability in Hg concentration in the cryosphere. Recent advancements in the genetic and physicochemical mechanisms of Hg methylation are also presented. Finally, we summarize and propose a method to study the unsolved issues of Hg methylation in the cryosphere.

Isotopic evidence for seasonality of microbial internal nitrogen cycles in a temperate forested catchment with heavy snowfall

The Hokuriku district of central Japan receives high levels of precipitation during winter, largely in the form of snow. This study aimed to elucidate the internal nitrogen dynamics in this temperate forested region with heavy snowfall using the triple oxygen and nitrogen isotopic compositions of NO₃^-. The isotopic compositions of NO₃^- in atmospheric depositions (P and Tf), with terrestrial components of the soil layer (A0, S25, S55, and S90), ground water (G), and output (St) were measured from 2015 to 2016 in a forested catchment located in the southern area of the Ishikawa Prefecture, Japan. Seasonal distributions of Δ¹⁷O(NO₃^-) showed a decreasing trend from the inputs to outputs of the ecosystem. We found relatively constant Δ¹⁷O(NO₃^-) values in the output components (G and St), but found highly fluctuating Δ¹⁷O(NO₃^-) values resulting from the seasonal variations in the nitrification activity within soil waters. Specifically, we observed a lower nitrifying activity in the top soil layer throughout cold periods, presumably due to the input of cold melted snow water. The general trend of increasing δ¹⁵N(NO₃^-) value from the input to output components, with the changes in denitrification hotspots from shallow to deeper soil layer, can be observed between warm and cold periods. Thus, the seasonal changes of hotspots related to microbial nitrification and denitrification could be noted due to the seasonal changes in the isotopic compositions of nitrate. The estimated ecosystem-scale gross nitrification and denitrification rates are low; however, the output components are relatively stable with low concentrations of nitrate, indicating that the plant uptake of nitrogen most probably occurs at greater rates and scales in this forested ecosystem. Future nitrogen deposition and the vulnerable dynamics of snow melting are likely to have impactful consequences on such localities.

Diversity of metals and metal-interactive bacterial populations in different types of Arctic snow and frost flowers: Implications on snow freeze-melt processes in a changing climate

Arctic snow has been shown to be a reactive interface for key physical, chemical, and microbiological processes, affecting the Arctic's oxidation, biodiversity, radiation, and climate. To explore the potential links between snow-borne metal contaminants and metal-interactive bacteria, to freezing/melting processes, we performed concurrent chemical characterization, genomic, and morphological analysis of five different Arctic snowpack (accumulated, blowing, fresh falling, surface hoar, and wind pack snow) and frost flower in Utqiaġvik (Barrow), Alaska, using Montreal urban snow as reference. Several complementary analytical techniques, including triple quad ICP-MS/MS along with various chromatography techniques, thermal ionization mass spectrometer (TIMS), high-resolution transition electron microscopy with electron dispersive X-ray spectroscopy (HR-TEM/EDS), and next generation sequencing (NGS), were deployed. Distinct metal composition and bacterial distribution among samples were observed. The concentration of 27 different transition, post-transition, rare, and radioactive metals were determined in molten snow and frost flower, as well as filtered samples. The range of three highest detected metal concentrations among samples were: Hg (3.294-134.485 μg/L), Fe (0.719-34.469 μg/L), and Sr (1.676-19,297.000 μg/L). NGS analysis led to the identification of metal interacting bacteria in all types of snow and frost flowers in the Arctic (blowing snow (1239), surface hoar snow (2243), windpack (2431), frost flowers (1440)), and Montreal urban snow (5498)) with specific bacterial genera such as: Acinetobacter, Arcenicella, Azospirillum (surface hoar snow), Arthrobacter, Paenibacillus (blowing snow), and Cycloclasticus, OM182 clade (frost flower). Several types of bacteria with confirmed or associated ice nucleation activity were observed in different types of snow, and frost flower including Pseudomonas genera (e.g., Pseudomonas fluorescens), Flavobacterium, Corynebacterium, and Pseudoxanthomonas. The implications of the above findings to snow-air interactions including nanoparticles, namely during melting and freezing cycles, and to probe the impact of various natural and anthropogenic activities are herein discussed.

REDUCTION IN AMBIENT GAMMA DOSE RATE FROM RADIOCESIUM DUE TO SNOW COVER

In the present study, variations in ambient gamma dose rate associated with snow cover were examined in a radioactive-contaminated site in Fukushima Prefecture, Japan. The ambient gamma dose rates decreased with increasing snow depth. The reduction trends were different between fresh snow (0.1-0.2 g/cm3) and granular snow (0.3-0.4 g/cm3) depending on snow density. Snow cover water content (snow water equivalent) calculated from snow depth and density was a key parameter governing the reduction in the ambient gamma dose rate. The ambient gamma dose rates reduced to 0.6 and 0.5 at 4 g/cm2 and 8 g/cm2 of snow water equivalent, respectively. Based on gamma-ray flux density distributions, the ambient gamma dose rates from the primary gamma rays decreased more compared to those from scattered gamma rays due to snow cover.

Athabasca oil sands region snow contains efficient micron and nano-sized ice nucleating particles

The Athabasca Oil Sands Region (AOSR) in Alberta, Canada, is an important source of atmospheric pollutants, such as aerosols, that have repercussions on both the climate and human health. We show that the mean freezing temperature of snow-borne particles from AOSR was elevated (-7.1 ± 1.8 °C), higher than mineral dust which freezes at ∼ -15 °C and is recognized as one of the most relevant ice nuclei globally. Ice nucleation of nanosized snow samples indicated an elevated freezing ability (-11.6 ± 2.0 °C), which was statistically much higher than snow-borne particles from downtown Montreal. AOSR snow had a higher concentration (∼2 orders of magnitude) of >100 nm particles than Montreal. Triple quadrupole ICP-(QQQ)-MS/MS analysis of AOSR and Montreal snow demonstrated that most concentrations of metals, including those identified as emerging nanoparticulate contaminants, were much more elevated in AOSR in contrast to Montreal: 34.1, 34.1, 16.6, 5.8, 0.3, 0.1, and 9.4 mg/m³ for Cr, Ni, Cu, As, Se, Cd, and Pb respectively, in AOSR and 1.3, 0.3, 2.0, <0.03, 0.1, 0.03, and 1.2 mg/m³ in Montreal snow. High-resolution Scanning Transmission Electron Microscopy/Energy-dispersive X-ray Spectroscopy (STEM-EDS) imaging provided evidence for various anthropogenic nano-materials, including carbon nanotubes resembling structures, in AOSR snow up to 7-25 km away from major oil sands upgrading facilities. In summary, particles characterized as coming from oil sands are more efficient at ice nucleation. We discuss the potential impacts of AOSR emissions on atmospheric and microphysical processes (ice nucleation and precipitation) both locally and regionally.

Snow gauge undercatch and its effect on the hydrogen and oxygen stable isotopic composition of precipitation

We investigated the influence of post-collection changes and snow gauge undercatch on the stable isotopic compositions of winter precipitation. Post-collection changes by evaporation or sublimation can be severe, and may be minimized, but not eliminated, by emptying collection gauges immediately after snowfall. Snow gauge undercatch caused two main effects: a small direct effect caused by preferential separation of snow particles during snowfall, and a much larger effect on the measured stable isotopic compositions of average annual precipitation as a result of under representation of winter precipitation. Despite these effects, however, we found little change to calculated local meteoric water lines (LMWL) for Saskatoon, SK, Canada. A comprehensive 27-year LMWL for Saskatoon which incorporates these effects can be described by δ²H = 7.69 ± 0.096 × δ¹⁸O - 2.22 ± 1.72 (r² = 0.97, n = 208).

Hydrochemical assessment (major ions and Hg) of meltwater in high altitude glacierized Himalayan catchment

Snowpack and glacial melt samples were collected to understand the hydrochemical, isotopic characteristics and the source of Hg contamination in high altitude glacierized Himalayan catchment. Both the snow and glacial melt were acidic in nature with calcium and magnesium as the dominant cations and bicarbonate and chloride as the dominant anions. The major ion concentrations for cations were found to be Ca²⁺ > Mg²⁺ > Na⁺ > K⁺ and HCO₃^- > Cl^- > SO₄^2- > NO₃^- for anions. The atmospheric processes like the precipitation source and aerosol scavenging control the snow chemistry and the weathering of the rocks modify the hydrochemistry of glacial melt. The samples of both the snow and glacial melt were classified as Ca-Mg-HCO₃^- type. The concentration of Hg in snow (154.95 ng L^-1) and glacial melt (112.04 ng L^-1) was highest (still lower compared to the maximum permissible limit (1000 ng L^-1) by WHO in drinking water) during summer season (August-September) and lowest (snow 2.2 and 40.01 ng L^-1 for glacial melt) during winter (November). The results reveal that mercury concentration in snowpacks is attributed to the combined mixing of long-range transport of pollutants via westerlies throughout the year and the industrial effluents coming from highly industrial belts of Panjab, Haryana, Rajasthan, Indo-Gangetic plains, and neighboring areas via southwest monsoons during August-September. However, in glacial melt, the Hg concentration was typically controlled by rate of melting, leaching, and percolation. Higher degree and rate of glacial melting decreases the Hg concentration in glacial melt. Stable isotopic analysis and backward air mass trajectory modeling also corroborate the source of precipitation from southwest monsoons during August-September, with its air mass trajectories passing through the highly industrialized belts of Indo-Gangetic plain and adjoining areas.

Elucidation of contamination sources for poly- and perfluoroalkyl substances (PFASs) on Svalbard (Norwegian Arctic)

A combination of local (i.e. firefighting training facilities) and remote sources (i.e. long-range transport) is assumed to be responsible for the occurrence of per- and polyfluoroalkyl substances (PFASs) in Svalbard (Norwegian Arctic). However, no systematic elucidation of local PFASs sources has been conducted yet. Therefore, a survey was performed aiming at identifying local PFAS pollution sources on the island of Spitsbergen (Svalbard, Norway). Soil, freshwater (lake, draining rivers), seawater, meltwater run-off, surface snow and coastal sediment samples were collected from Longyearbyen (Norwegian mining town), Ny-Ålesund (research facility) and the Lake Linnévatnet area (background site) during several campaigns (2014-2016) and analysed for 14 individual target PFASs. For background site (Linnévatnet area, sampling during April to June 2015), ΣPFAS levels ranged from 0.4 to 4 ng/L in surface lake water (n = 20). PFAS in meltwater from the contributing glaciers showed similar concentrations (~ 4 ng/L, n = 2). The short-chain perfluorobutanoate (PFBA) was predominant in lake water (60-80% of the ΣPFASs), meltwater (20-30%) and run-off water (40%). Long-range transport is assumed to be the major PFAS source. In Longyearbyen, five water samples (i.e. 2 seawater, 3 run-off) were collected near the local firefighting training site (FFTS) in November 2014 and June 2015, respectively. The highest PFAS levels were found in FFTS meltwater run-off (118 ng/L). Perfluorooctane sulfonic acid (PFOS) was the most abundant compound in the FFTS meltwater run-off (53-58% PFASs). At the research station Ny-Ålesund, seawater (n = 6), soil (n = 9) and freshwater (n = 10) were collected in June 2016. Low ΣPFAS concentrations were determined for seawater (5-6 ng/L), whereas high ΣPFAS concentrations were found in run-off water (113-119 ng/L) and soil (211-800 ng/g dry weight (dw)) collected close to the local FFTS. In addition, high ΣPFAS levels (127 ng/L) were also found in freshwater from lake Solvatnet close to former sewage treatment facility. Overall, at both FFTS-affected sites (soil, water), PFOS was the most abundant compound (60-69% of ΣPFASs). FFTS and landfill locations were identified as major PFAS sources for Svalbard settlements.

Light-absorbing impurities in snow of the Indian Western Himalayas: impact on snow albedo, radiative forcing, and enhanced melting

Seasonal snow cover in the Himalayas acts as source of fresh water for several Asian rivers such as Indus, Ganges, Brahmaputra, and Yangtze. Early loss of seasonal snow exposes the ice layer of the glaciers directly to sunlight, consequently leading to their ablation and alterations in discharge of glacier-fed rivers. Therefore, any alteration in the melting rate of the Himalayan snow pack can significantly affect the ecological balance in the region. Besides global warming, enhanced melting of snow, caused by light-absorbing impurities (LAIs) such as dust and elemental carbon (EC), has also been recognized as prominent cause of enhanced melting of snow in the Himalayas of China and Nepal. However, in light of vast area of the Himalayas and persistent emissions from India, studies, emphasizing the potential of LAIs to substantially affect the snow radiation budget of snow cover in IWHs, are still scanty. Therefore, in this study, field campaigns were made on three glaciers, i.e., Hamta, Beas Kund, and Deo Tibba, in IWHs to collect snow samples for estimation of LAIs. Snow of the studied glaciers was observed to be contaminated with 13.02 to 74.57 ng/g of EC and 32.14 to 216.54 μg/g of dust. Albedo simulations done using SNow and ICe Aerosol Radiation (SNICAR) model indicated that besides the changes caused by increased grain size, EC and dust, cumulatively induced 0.60 to 32.65% reduction in albedo of snow. Further assessment, constrained by measurements, illustrated that radiative forcing (RF), of 1.8 to 80 W/m², was instigated due to enhanced thermal absorption of snow. Ten hours of daily mean RFs in this range could correspond to 3 to 9.65 mm/d of snow melt and contribute significantly in reducing the seasonal snow cover in IWHs. Considering the consequences of LAIs-induced snow melt and lack of in situ observations in the IWHs, the outcomes of this study could assist researchers and policy makers in developing efficient climate models and framing mitigation measures, respectively.

Perfluorinated alkyl substances in snow as an atmospheric tracer for tracking the interactions between westerly winds and the Indian Monsoon over western China

Snow is an efficient scavenger for the deposition of contaminants. Atmospheric transport and snow deposition jointly control the distribution of pollutants in remote mountain/polar regions. But can the contaminants contained within snow be used to reflect the interactions of air circulation patterns? The physicochemical properties of perfluoroalkyl substances (PFASs) are unique because of their high water solubilities. Taking advantage of this, 15 surface-snow and 3 snow-pit samples were collected across a vast area of western China (spanning 20° of latitude and 25° of longitude), to investigate the concentrations, composition profiles (fingerprints), and deposition fluxes of PFASs. Both a high concentration (3974 pg/L) and deposition flux (4.0 μg/m²/yr) for a total of 16 PFASs were found in the snow at Yulong, the most southern sample site, possibly because of its close proximity to source regions of pollutants in South Asia and high rate of snow deposition. Perfluorobutanoic acid was the most commonly found chemical in snow, but in general the PFAS composition in the snow of western China showed large spatial differences, with long-chain (C > 10) PFASs being relatively dominant in the north and west of the region and short-chain (C < 6) PFASs in the south and east. On the basis of the different compositions of PFASs in the snow of western China and the previously reported features of pollutant sources in Europe and India, we found that PFASs in snow can be used as an atmospheric tracer for tracking the interactions between westerly winds and the Indian Monsoon. The belt along 33°N is a key location where both the Indian Monsoon and westerly winds can arrive/interact; however, the contribution of the monsoon was found to be above 70%, while that of the westerly winds can be lower than 30%. The western part of the 33°N belt was found to be more vulnerable to the Indian Monsoon, and could be grouped into the monsoon domain, while the influence of the westerly winds increased from west to east along the belt. This finding is opposite to previous results, which reported that the western part of the 33°N belt was mainly under the influence of the westerly winds, and for the first time quantifies the relative contribution of westerly winds and the Indian Monsoon to the atmospheric transport of chemicals.

Effect of snowmelt infiltration on groundwater recharge in a seasonal soil frost area: a case study in Northeast China

The effect of spring snowmelt infiltration in a seasonal soil frost area on groundwater recharge was evaluated by systematically monitoring meteorological factors, soil temperature and humidity, groundwater table and temperature, electrical conductivity, and the value of δ¹⁸O in a small field site over a 2-year period. The variation of soil temperature and humidity, groundwater table during the freezing period, and the snowmelt period respectively, as well as their correspondence to the relevant environmental factors, and the influencing factors of the permeability of frozen layer were analyzed. The results showed that the evaluation of precipitation infiltration in seasonal soil frost areas should be divided into three stages: a non-freezing period, a freezing period, and a snowmelt period. Snow is the main form of precipitation during the freezing period, and groundwater cannot be recharged. During the snowmelt period of spring, the snow cover that accumulated during the freezing period infiltrates together with rainfall and has a significant effect on groundwater recharge. The general precipitation infiltration process occurs after the frozen soil thaws completely. These research results can improve the accuracy of groundwater recharge calculations for snowmelt infiltration in the seasonal soil frost area of Northeast China and provide a scientific basis for the evaluation and management of regional water resources.

Environmental conditions affecting re-release from particulate matter of 4-Nonylphenol into an aqueous medium

4-nonylphenol is a persistent organic pollutant with endocrine-disrupting properties. A nonpolar product of microbial degradation derived from the surfactant nonylphenol polyethoxylate, 4-nonylphenol is capable of long-range transport attached to particulates. Bioactive concentrations of 4-nonylphenol have been found in the surface water, soils, snow, and particulate matter of the Eastern Sierra Nevada Mountains (USA) hundreds of miles from their origins. As a result of particulate deposition, seasonal and glacial snow pack concentrations measured 20 to 100 times higher than in surface waters. Batch desorption assays were run on particulate matter dosed with 4-nonylphenol. Desorption was measured in 63 to 500 μm particles under 2 different temperature conditions with varying fractions of organic carbon in turbulent or undisturbed states. Lower temperatures (4 °C) decreased the mean percentage of 4-nonylphenol released from particulates in disturbed and undisturbed conditions, whereas the mean percentage of 4-nonylphenol released at 20 °C was reduced by agitation. The effect of agitation at 4 °C was not practically or statistically significant. Particulates with a higher percentage of organic carbon (75%) released very little of the bound 4-nonylphenol (0.53%) compared with particulates containing 4 to 5% of organic carbon that released up to 13%. Larger particles released the least amount of 4-nonylphenol, whereas smaller particles released the most amount. Water and sediment samples taken from below the Palisades Glacier in the Sierra Nevada Mountains showed the greatest 4-nonylphenol concentrations directly below the glacier, implying that glacial particulates will release adsorbed 4-nonylphenol. Environ Toxicol Chem 2019;38:350-360. © 2018 SETAC.