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The Arctic is one of the most rapidly warming regions of the Earth, with predicted temperature increases of 5–7 ∘C and the accompanying extensive retreat of Arctic glacial systems by 2100. Retreating glaciers will reveal new land surfaces for microbial colonisation, ultimately succeeding to tundra over decades to centuries. An unexplored dimension to these changes is the impact upon the emission and consumption of halogenated organic compounds (halocarbons). Halocarbons are involved in several important atmospheric processes, including ozone destruction, and despite considerable research, uncertainties remain in the natural cycles of some of these compounds. Using flux chambers, we measured halocarbon fluxes across the glacier forefield (the area between the present-day position of a glacier's ice-front and that at the last glacial maximum) of a high-Arctic glacier in Svalbard, spanning recently exposed sediments (<10 years) to approximately 1950-year-old tundra. Forefield land surfaces were found to consume methyl chloride (CH3Cl) and methyl bromide (CH3Br), with both consumption and emission of methyl iodide (CH3I) observed. Bromoform (CHBr3) and dibromomethane (CH2Br2) have rarely been measured from terrestrial sources but were here found to be emitted across the forefield. Novel measurements conducted on terrestrial cyanobacterial mats covering relatively young surfaces showed similar measured fluxes to the oldest, vegetated tundra sites for CH3Cl, CH3Br, and CH3I (which were consumed) and for CHCl3 and CHBr3 (which were emitted). Consumption rates of CH3Cl and CH3Br and emission rates of CHCl3 from tundra and cyanobacterial mat sites were within the ranges reported from older and more established Arctic tundra elsewhere. Rough calculations showed total emissions and consumptions of these gases across the Arctic were small relative to other sources and sinks due to the small surface area represented by glacier forefields. We have demonstrated that glacier forefields can consume and emit halocarbons despite their young age and low soil development, particularly when cyanobacterial mats are present.
2020
Atmospheric concentration of legacy (LFRs) and emerging flame retardants (EFRs) including 8 polybrominated diphenyl ethers (PBDEs), 6 novel brominated flame retardants (NBFRs), 2 dechlorane plus isomers (DP), and 8 chlorinated organophosphate flame retardants (OPFRs) were consecutively measured in eight major cities across Pakistan. A total of 96 samples (48 PM2.5 & 48 PUFs) were analyzed and the concentrations of ∑8PBDEs (gaseous+particulate) ranged between 40.8 and 288 pg/m3 with an average value of 172 pg/m3. ∑6NBFRs ranged between 12.0 and 35.0 pg/m3 with an average value of 22.5 pg/m3 while ∑8OPFRs ranged between 12,900–40,800 pg/m3 with an average of 24,700 pg/m3. Among the studied sites, Faisalabad city exhibited the higher concentrations of FRs among all cities which might be a consequence of textile mills and garment manufacturing industries. While analyzing the diurnal patterns, OPFRs depicted higher concentrations during night-time. The estimated risks of all groups of FRs from inhalation of ambient air were negligible for all the cities, according to USEPA guidelines. Nonetheless, our study is the first to report gaseous and particulate concentrations of FRs in air on a diurnal basis across major cities in Pakistan, offering insights into the atmospheric fate of these substances in urban areas in a sub-tropical region.
2020
2020
Car Tire Crumb Rubber: Does Leaching Produce a Toxic Chemical Cocktail in Coastal Marine Systems?
Crumb rubber granulate (CRG) produced from end of life tires (ELTs) is commonly applied to synthetic turf pitches (STPs), playgrounds, safety surfaces and walkways. In addition to fillers, stabilizers, cross-linking agents and secondary components (e.g., pigments, oils, resins), ELTs contain a range of other organic compound and heavy metal additives. While previous environmental impact studies on CRG have focused on terrestrial soil and freshwater ecosystems, many sites applying CRG in Norway are coastal. The current study investigated the organic chemical and metal additive content of ‘pristine’ and ‘weathered’ CRG and their seawater leachates, as well as uptake and effects of leachate exposure using marine copepods (Acartia and Calanus sp.). A combination of pyrolysis gas chromatography mass spectrometry (py-GC-MS) and chemical extraction followed by GC-MS analysis revealed similar organic chemical profiles for pristine and weathered CRG, including additives such as benzothiazole, N-1,3-dimethylbutyl-N′-phenyl-p-phenylenediamine and a range of polycyclic aromatic hydrocarbons (PAHs) and phenolic compounds (e.g., bisphenols). ICP-MS analysis revealed g kg–1 quantities of Zn and mg kg–1 quantities of Fe, Mn, Cu, Co, Cr, Pb, and Ni in the CRG. A cocktail of organic additives and metals readily leached from the CRG into seawater, with the most abundant leachate components being benzothiazole and Zn, Fe, Co (metals), as well as detectable levels of PAHs and phenolic compounds. Concentrations of individual components varied with CRG source material and CRG to seawater ratio, but benzothiazole and Zn were typically the organic and metal components present at the highest concentrations in the leachates. While organic chemical concentrations in the leachates stabilized within days, metals continued to leach out over the 30-day period. Marine copepods exposed to high CRG leachate concentrations exhibited high mortalities within 48 h. The smaller lipid-poor Acartia had a higher sensitivity to leachates than the larger lipid-rich Calanus, indicating species-specific differences in vulnerability to leachates. The effect on survival was alleviated at lower leachate concentrations, indicating a dose-response relationship. Benzothiazole and its derivatives appear to be of concern owing to their proven toxicity, while bisphenols are also known to be toxic and were enriched in the leachates relative to the other compounds in the CRG.
2020
Satellite validation strategy assessments based on the AROMAT campaigns
The Airborne ROmanian Measurements of Aerosols and Trace gases (AROMAT) campaigns took place in Romania in September 2014 and August 2015. They focused on two sites: the Bucharest urban area and large power plants in the Jiu Valley. The main objectives of the campaigns were to test recently developed airborne observation systems dedicated to air quality studies and to verify their applicability for the validation of space-borne atmospheric missions such as the TROPOspheric Monitoring Instrument (TROPOMI)/Sentinel-5 Precursor (S5P). We present the AROMAT campaigns from the perspective of findings related to the validation of tropospheric NO2, SO2, and H2CO. We also quantify the emissions of NOx and SO2 at both measurement sites.
We show that tropospheric NO2 vertical column density (VCD) measurements using airborne mapping instruments are well suited for satellite validation in principle. The signal-to-noise ratio of the airborne NO2 measurements is an order of magnitude higher than its space-borne counterpart when the airborne measurements are averaged at the TROPOMI pixel scale. However, we show that the temporal variation of the NO2 VCDs during a flight might be a significant source of comparison error. Considering the random error of the TROPOMI tropospheric NO2 VCD (σ), the dynamic range of the NO2 VCDs field extends from detection limit up to 37 σ (2.6×1016 molec. cm−2) and 29 σ (2×1016 molec. cm−2) for Bucharest and the Jiu Valley, respectively. For both areas, we simulate validation exercises applied to the TROPOMI tropospheric NO2 product. These simulations indicate that a comparison error budget closely matching the TROPOMI optimal target accuracy of 25 % can be obtained by adding NO2 and aerosol profile information to the airborne mapping observations, which constrains the investigated accuracy to within 28 %. In addition to NO2, our study also addresses the measurements of SO2 emissions from power plants in the Jiu Valley and an urban hotspot of H2CO in the centre of Bucharest. For these two species, we conclude that the best validation strategy would consist of deploying ground-based measurement systems at well-identified locations.
2020
Seabirds like gulls are common indicators in contaminant monitoring. The herring gull (Larus argentatus) is a generalist with a broad range of dietary sources, possibly introducing a weakness in its representativeness of aquatic contamination. To investigate the herring gull as an indicator of contamination in an urban‐influenced fjord, the Norwegian Oslofjord, we compared concentrations of a range of lipophilic and protein‐associated organohalogen contaminants (OHCs), Hg, and dietary markers in blood (n = 15), and eggs (n = 15) between the herring gull and the strict marine‐feeding common eider (Somateria mollissima) in the breeding period of May 2017. Dietary markers showed that the herring gull was less representative of the marine food web than the common eider. We found higher concentrations of lipophilic OHCs (wet weight and lipid weight) and Hg (dry weight) in the blood of common eider (mean ± SE ∑PCB = 210 ± 126 ng/g ww, 60 600 ± 28 300 ng/g lw; mean Hg = 4.94 ± 0.438 ng/g dw) than of the herring gull (mean ± SE ∑PCB = 19.0 ± 15.6 ng/g ww, 1210 ± 1510 ng/g lw; mean Hg = 4.26 ± 0.438 ng/g dw). Eggs gave opposite results; higher wet weight and lipid weight OHC concentrations in the herring gull (mean ± SE ∑PCB = 257 ± 203 ng/g ww, 3240 ± 2610 ng/g lw) than the common eider (mean ± SE ∑PCB = 18.2 ± 20.8 ng/g ww, 101 ± 121 ng/g lw), resulting in higher OHC maternal transfer ratios in gulls than eiders. We suggest that the matrix differences are due to fasting during incubation in the common eider. We suggest that in urban areas, herring gull might not be representative as an indicator of marine contamination but rather urban contaminant exposure. The common eider is a better indicator of marine pollution in the Oslofjord. The results are influenced by the matrix choice, as breeding strategy affects lipid dynamics regarding the transfer of lipids and contaminants to eggs and remobilization of contaminants from lipids to blood during incubation, when blood is drawn from the mother. Our results illustrate the benefit of a multispecies approach for a thorough picture of contaminant status in urban marine ecosystems. Integr Environ Assess Manag 2020;00:1–12. © 2020 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC)
2020
Polycyclic aromatic hydrocarbons (PAHs) are not declining in Arctic air despite reductions in their global emissions. In Svalbard, the Longyearbyen coal-fired power plant is considered to be one of the major local sources of PAHs. Power plant stack emissions and ambient air samples, collected simultaneously at 1 km (UNIS) and 6 km (Adventdalen) transect distance, were analysed (gaseous and particulate phases separately) for 22 nitro-PAHs, 8 oxy-PAHs, and 16 parent PAHs by gas chromatography in combination with single quadrupole electron capture negative ionization mass spectrometry (GC-ECNI-MS) and gas chromatography in combination with triple quadrupole electron ionization mass spectrometry (GC-EI-MS/MS). Results confirm low levels of PAH emissions (Sum 16 PAHs D 1:5 μg/kg coal) from the power plant. Phenanthrene, 9,10-anthraquinone, 9- fluorenone, fluorene, fluoranthene, and pyrene accounted for 85% of the plant emission (not including naphthalene). A dilution effect was observed for the transect ambient air samples: 1.26+/- 0.16 and 0.63+/- 0.14 ng/m3 were the sum of all 47 PAH derivatives for UNIS and Adventdalen, respectively. The PAH profile was homogeneous for these recipient stations with phenanthrene and 9-fluorenone being most abundant. Multivariate statistical analysis confirmed coal combustion and vehicle and marine traffic as the predominant sources of PAHs. Secondary atmospheric formation of 9- nitroanthracene and 2C3-nitrofluoranthene was evaluated and concluded. PAHs partitioning between gaseous and particulate phases showed a strong dependence on ambient temperatures and humidity. The present study contributes important data which can be utilized to eliminate uncertainties in model predictions that aim to assess the extent and impacts of Arctic atmospheric contaminants.
2020
Atmospheric turbulence and in particular its effect on tracer dispersion may be measured by cameras sensitive to the absorption of ultraviolet (UV) sunlight by sulfur dioxide (SO2), a gas that can be considered a passive tracer over short transport distances. We present a method to simulate UV camera measurements of SO2 with a 3D Monte Carlo radiative transfer model which takes input from a large eddy simulation (LES) of a SO2 plume released from a point source. From the simulated images the apparent absorbance and various plume density statistics (centre-line position, meandering, absolute and relative dispersion, and skewness) were calculated. These were compared with corresponding quantities obtained directly from the LES. Mean differences of centre-line position, absolute and relative dispersions, and skewness between the simulated images and the LES were generally found to be smaller than or about the voxel resolution of the LES. Furthermore, sensitivity studies were made to quantify how changes in solar azimuth and zenith angles, aerosol loading (background and in plume), and surface albedo impact the UV camera image plume statistics. Changing the values of these parameters within realistic limits has negligible effects on the centre-line position, meandering, absolute and relative dispersions, and skewness of the SO2 plume. Thus, we demonstrate that UV camera images of SO2 plumes may be used to derive plume statistics of relevance for the study of atmospheric turbulent dispersion.
2020
Plants rely on spectral cues present in their surroundings, generated by the constantly changing light environment, to guide their growth and reproduction. Photoreceptors mediate the capture of information by plants from the light environment over a wide range of wavelengths, but despite extensive evidence that plants respond to various light cues, only fragmentary data have been published showing patterns of diurnal, seasonal and geographical variation in the spectral composition of daylight. To illustrate patterns in spectral photon ratios, we measured time series of irradiance spectra at two distinct geographical and climatological locations, Helsinki, Finland and Gual Pahari, India. We investigated the drivers behind variation of the spectral photon ratios measured at these two locations, based on the analysis of over 400 000 recorded spectra. Differences in spectral irradiance were explained by different atmospheric factors identified through multiple regression model analysis and comparison to spectral irradiance at ground level simulated with a radiative transfer model. Local seasonal and diurnal changes in spectral photon ratios were related to solar elevation angle, atmospheric water-vapour content and total ozone column thickness and deviated from their long-term averages to an extent likely to affect plant photobiology. We suggest that future studies should investigate possible effects of varying photon ratios on terrestrial plants. Solar elevation angle especially affects the patterns of B:G and B:R ratios. Water vapour has a large effect on the R:FR photon ratio and modelled climate scenarios predict that increasing global temperatures will result in increased atmospheric water vapour. The development of proxy models, utilising available data from weather and climate models, for relevant photon ratios as a function of solar elevation angle and atmospheric factors would facilitate the interpretation of results from past, present and future field studies of plants and vegetation.
2020
The white-tailed eagle (Haliaeetus albicilla) in Scandinavia has suffered from impaired reproduction due to high exposure to industrial pollution between the 1960s and 1980s. While population numbers are rising again, new contaminants, such as per- and polyfluoroalkyl substances (PFAS), are increasingly found in high trophic avifauna and are of concern to potentially impact once again on population health. In the present study, we examined PFAS levels in plasma of white-tailed eagle nestlings from northern Norway over the last decade (2008–2017). While PFOA and PFNA exposure did not follow a significant time trend, PFOS and PFHxS concentrations decreased over time, and ≥C11 perfluorinated carboxylic acids only seem to level off during the last four years. This may in fact be the first evidence for a change in the trend for some of these compounds. Furthermore, since several PFAS are expected to be highly present in aqueous film-forming foams used at airports, we also investigate the potential of the two main airports in the region to act as hotspots for PFAS. Our results indeed show decreasing exposure to PFOA with distance to the airports. Altogether, our results seem to show that legislation actions are effective, and continued concern for PFAS exposure of high trophic wildlife is still warranted, even in the northern environment.
2020
Grouping strategies are needed for per- and polyfluoroalkyl substances (PFAS), in part, because it would be time and resource intensive to test and evaluate the more than 4700 PFAS on the global market on a chemical-by-chemical basis. In this paper we review various grouping strategies that could be used to inform actions on these chemicals and outline the motivations, advantages and disadvantages for each. Grouping strategies are subdivided into (1) those based on the intrinsic properties of the PFAS (e.g. persistence, bioaccumulation potential, toxicity, mobility, molecular size) and (2) those that inform risk assessment through estimation of cumulative exposure and/or effects. The most precautionary grouping approach of those reviewed within this article suggests phasing out PFAS based on their high persistence alone (the so-called “P-sufficient” approach). The least precautionary grouping approach reviewed advocates only grouping PFAS for risk assessment that have the same toxicological effects, modes and mechanisms of action, and elimination kinetics, which would need to be well documented across different PFAS. It is recognised that, given jurisdictional differences in chemical assessment philosophies and methodologies, no one strategy will be generally acceptable. The guiding question we apply to the reviewed grouping strategies is: grouping for what purpose? The motivation behind the grouping (e.g. determining use in products vs. setting guideline levels for contaminated environments) may lead to different grouping decisions. This assessment provides the necessary context for grouping strategies such that they can be adopted as they are, or built on further, to protect human and environmental health from potential PFAS-related effects.
2020
Solar UV radiation measurements in Marambio, Antarctica, during years 2017–2019
In March 2017, measurements of downward global irradiance of ultraviolet (UV) radiation were started with a multichannel GUV-2511 radiometer in Marambio, Antarctica (64.23∘ S; 56.62∘ W), by the Finnish Meteorological Institute (FMI) in collaboration with the Servicio Meteorológico Nacional (SMN). These measurements were analysed and the results were compared to previous measurements performed at the same site with the radiometer of the Antarctic NILU-UV network during 2000–2008 and to data from five stations across Antarctica. In 2017/2018 the monthly-average erythemal daily doses from October to January were lower than those averaged over 2000–2008 with differences from 2.3 % to 25.5 %. In 2017/2018 the average daily erythemal dose from September to March was 1.88 kJ m−2, while in 2018/2019 it was 23 % larger (2.37 kJ m−2). Also at several other stations in Antarctica the UV radiation levels in 2017/2018 were below average. The maximum UV indices (UVI) in Marambio were 6.2 and 9.5 in 2017/2018 and 2018/2019, respectively, whereas during years 2000–2008 the maximum was 12. Cloud cover, the strength of the polar vortex and the stratospheric ozone depletion are the primary factors that influence the surface UV radiation levels in Marambio. The lower UV irradiance values in 2017/2018 are explained by the high ozone concentrations in November, February and for a large part of October. The role of cloud cover was clearly seen in December, and to a lesser extent in October and November, when cloud cover qualitatively explains changes which could not be ascribed to changes in total ozone column (TOC). In this study, the roles of aerosols and albedo are of minor influence because the variation of these factors in Marambio was small from one year to the other. The largest variations of UV irradiance occur during spring and early summer when noon solar zenith angle (SZA) is low and the stratospheric ozone concentration is at a minimum (the so-called ozone hole). In 2017/2018, coincident low total ozone column and low cloudiness near solar noon did not occur, and no extreme UV indices were measured.
2020
Arctic sea-ice loss intensifies aerosol transport to the Tibetan Plateau
The Tibetan Plateau (TP) has recently been polluted by anthropogenic emissions transported from South Asia, but the mechanisms conducive to this aerosol delivery are poorly understood. Here we show that winter loss of Arctic sea ice over the subpolar North Atlantic boosts aerosol transport toward the TP in April, when the aerosol loading is at its climatological maximum and preceding the Indian summer monsoon onset. Low sea ice in February weakens the polar jet, causing decreased Ural snowpack via reduced transport of warm, moist oceanic air into the high-latitude Eurasian interior. This diminished snowpack persists through April, reinforcing the Ural pressure ridge and East Asian trough, segments of a quasi-stationary Rossby wave train extending across Eurasia. These conditions facilitate an enhanced subtropical westerly jet at the southern edge of the TP, invigorating upslope winds that combine with mesoscale updrafts to waft emissions over the Himalayas onto the TP.
2020
The 2018 drought was one of the worst European droughts of the twenty-first century in terms of its severity, extent and duration. The effects of the drought could be seen in a reduction in harvest yields in parts of Europe, as well as an unprecedented browning of vegetation in summer. Here, we quantify the effect of the drought on net ecosystem exchange (NEE) using five independent regional atmospheric inversion frameworks. Using a network of atmospheric CO2 mole fraction observations, we estimate NEE with at least monthly and 0.5° × 0.5° resolution for 2009–2018. We find that the annual NEE in 2018 was likely more positive (less CO2 uptake) in the temperate region of Europe by 0.09 ± 0.06 Pg C yr−1 (mean ± s.d.) compared to the mean of the last 10 years of −0.08 ± 0.17 Pg C yr−1, making the region close to carbon neutral in 2018. Similarly, we find a positive annual NEE anomaly for the northern region of Europe of 0.02 ± 0.02 Pg C yr−1 compared the 10-year mean of −0.04 ± 0.05 Pg C yr−1. In both regions, this was largely owing to a reduction in the summer CO2 uptake. The positive NEE anomalies coincided spatially and temporally with negative anomalies in soil water. These anomalies were exceptional for the 10-year period of our study.
This article is part of the theme issue ‘Impacts of the 2018 severe drought and heatwave in Europe: from site to continental scale’.
2020
2020
Aerosol particles are major short-lived climate forcers, because of their ability to interact with incoming solar radiation. Therefore, addressing mean levels and sources of Arctic aerosols is of high importance in the battle against climate change, due to the Arctic amplification. In the Eastern Arctic, from Finland to Alaska, only one monitoring station exists (HMO Tiksi) and the levels of the Arctic aerosols are usually recorded by sporadic campaigns, while other stations exist in Canada, Finland and Europe. From April 2015 to December 2016, the research station "Ice Base Cape Baranova" (79°16.82'N, 101°37.05'E), located on the Bolshevik island was established in the Siberian high Arctic. Samples were analyzed for equivalent Black Carbon (eBC), Organic Carbon (OC), Elemental Carbon (EC), water-soluble ions, and elements. To identify the spatial origin of the sources, the Potential Source Contributions Function (PSCF) was used in combination with FLEXPART emission sensitivities. OC is the most dominant PM compound in the Ice Cape Baranova station and mostly originates from gas flaring and other industrial regions at lower latitudes, as well as from biomass burning during summertime. Sulfate concentrations were affected by anthropogenic sources in the cold seasons and by natural sources in the warm ones showing distinct seasonal patterns. K+ and Mg2+ originate from sea-salt in winter and from forest fires in summer. The interannual variability of eBC was in good agreement with the general Arctic seasonal trends and was mainly affected by gas flaring, low latitude industrial sources and from biomass burning emissions. Cl− depletion was very low, while Na+ and Cl− originated from the locally formed sea spray.
2020
2020
Energetic particle precipitation is one of the main processes by which the sun influences atmospheric composition and structure. The polar middle atmosphere is chemically disturbed by the precipitation-induced production of nitric oxides (NOx) and hydrogen oxides (HOx) and the associated ozone (O3) loss, but the importance for the dynamics is still debated. The role of precipitating medium energy electrons (MEEs), which are able to penetrate into the mesosphere, has received increased attention, but has only recently begun to be incorporated in chemistry-climate models. We use the NCAR Whole Atmosphere Community Climate Model (WACCM) to study the climate impact from MEE precipitation by performing two idealized ensemble experiments under pre-industrial conditions, with and without the MEE forcing, over the period of the solar cycle 23 (only full calendar years, 1997–2007). Each experiment includes 20 11-year ensemble members, total 220 years. Our results indicate a strong month-to-month variability in the dynamical response to MEE throughout the winter period. We find a strengthening of the polar vortex in the northern hemisphere during December, but the signal decays rapidly in the following months. The polar vortex strengthening is likely attributable to planetary wave reduction due to increased zonal symmetries in upper stratospheric ozone heating, initially triggered by MEE-induced NOx advected into the sunlit regions. We also find a similar early winter polar vortex strengthening in the southern hemisphere during June. Changes in mean meridional circulation accompany these anomalous wave forcings, leading to dynamically-induced vertical temperature dipoles at high latitudes. The associated weakening of the stratospheric mean meridional circulation results in an upper stratospheric polar ozone deficit in early winter. This polar cap ozone deficit is strongest in the southern hemisphere and contributes to a polar vortex weakening in late winter, in concert with increased planetary wave forcing. In both hemispheres, the stratospheric polar vortex signal seems to migrate downwards into the troposphere and to the surface.
2020
Social-Environmental Analysis for the Management of Coastal Lagoons in North Africa
This study provides an overview of 11 lagoons in North Africa, from the Atlantic to the Eastern Mediterranean. Lagoons are complex, transitional, coastal zones providing valuable ecosystem services that contribute to the welfare of the human population. The main economic sectors in the lagoons included fishing, shellfish harvesting, and salt and sand extraction, as well as maritime transport. Economic sectors in the areas around the lagoons and in the watershed included agriculture, tourism, recreation, industrial, and urban development. Changes were also identified in land use from reclamation, changes in hydrology, changes in sedimentology from damming, inlet modifications, and coastal engineering. The human activities in and around the lagoons exert multiple pressures on these ecosystems and result in changes in the environment, affecting salinity, dissolved oxygen, and erosion; changes in the ecology, such as loss of biodiversity; and changes in the delivery of valuable ecosystem services. Loss of ecosystem services such as coastal protection and seafood affect human populations that live around the lagoons and depend on them for their livelihood. Adaptive management frameworks for social–ecological systems provide options that support decision makers with science-based knowledge to deliver sustainable development for ecosystems. The framework used to support the decision makers for environmental management of these 11 lagoons is Drivers–Activities–Pressures–State Change–Impact (on Welfare)–Responses (as Measures).
2020
Understanding the drivers and effects of exposure to contaminants such as mercury (Hg) and organochlorine compounds (OCs) in Antarctic wildlife is still limited. Yet, Hg and OCs have known physiological and fitness effects in animals, with consequences on their populations. Here we measured total Hg (a proxy of methyl-Hg) in blood cells and feathers, and 12 OCs (seven polychlorinated biphenyls, PCBs, and five organochlorine pesticides, OCPs) in plasma of 30 breeding female Antarctic petrels Thalassoica antarctica from one of the largest colonies in Antarctica (Svarthamaren, Dronning Maud Land). This colony is declining and there is poor documentation on the potential role played by contaminants on individual physiology and fitness. Carbon (δ13C) and nitrogen (δ15N) stable isotope values measured in the females' blood cells and feathers served as proxies of their feeding ecology during the pre-laying (austral spring) and moulting (winter) periods, respectively. We document feather Hg concentrations (mean ± SD, 2.41 ± 0.83 μg g−1 dry weight, dw) for the first time in this species. Blood cell Hg concentrations (1.38 ± 0.43 μg g−1 dw) were almost twice as high as those reported in a recent study, and increased with pre-laying trophic position (blood cell δ15N). Moulting trophic ecology did not predict blood Hg concentrations. PCB concentrations were very low (Σ7PCBs, 0.35 ± 0.31 ng g−1 wet weight, ww). Among OCPs, HCB (1.02 ± 0.36 ng g−1 ww) and p, p’-DDE (1.02 ± 1.49 ng g−1 ww) residues were comparable to those of ecologically-similar polar seabirds, while Mirex residues (0.72 ± 0.35 ng g−1 ww) were higher. PCB and OCP concentrations showed no clear relationship with pre-laying or moulting feeding ecology, indicating that other factors overcome dietary drivers. OC residues were inversely related to body condition, suggesting stronger release of OCs into the circulation of egg-laying females upon depletion of their lipid reserves. Egg volume, hatching success, chick body condition and survival were not related to maternal Hg or OC concentrations. Legacy contaminant exposure does not seem to represent a threat for the breeding fraction of this population over the short term. Yet, exposure to contaminants, especially Mirex, and other concurring environmental stressors should be monitored over the long-term in this declining population.
2020
Dichloromethane (CH2Cl2) and perchloroethylene (C2Cl4) are chlorinated very short lived substances (Cl‐VSLS) with anthropogenic sources. Recent studies highlight the increasing influence of such compounds, particularly CH2Cl2, on the stratospheric chlorine budget and therefore on ozone depletion. Here, a multiyear global‐scale synthesis inversion was performed to optimize CH2Cl2 (2006–2017) and C2Cl4 (2007–2017) emissions. The approach combines long‐term surface observations from global monitoring networks, output from a three‐dimensional chemical transport model (TOMCAT), and novel bottom‐up information on prior industry emissions. Our posterior results show an increase in global CH2Cl2 emissions from 637 ± 36 Gg yr−1 in 2006 to 1,171 ± 45 Gg yr−1 in 2017, with Asian emissions accounting for 68% and 89% of these totals, respectively. In absolute terms, Asian CH2Cl2 emissions increased annually by 51 Gg yr−1 over the study period, while European and North American emissions declined, indicating a continental‐scale shift in emission distribution since the mid‐2000s. For C2Cl4, we estimate a decrease in global emissions from 141 ± 14 Gg yr−1 in 2007 to 106 ± 12 Gg yr−1 in 2017. The time‐varying posterior emissions offer significant improvements over the prior. Utilizing the posterior emissions leads to modeled tropospheric CH2Cl2 and C2Cl4 abundances and trends in good agreement to those observed (including independent observations to the inversion). A shorter C2Cl4 lifetime, from including an uncertain Cl sink, leads to larger global C2Cl4 emissions by a factor of ~1.5, which in some places improves model‐measurement agreement. The sensitivity of our findings to assumptions in the inversion procedure, including CH2Cl2 oceanic emissions, is discussed.
2020
Measurements of solar ultraviolet radiation (UVR) performed between January and June 2020 at 10 Arctic and subarctic locations are compared with historical observations. Differences between 2020 and prior years are also assessed with total ozone column and UVR data from satellites. Erythemal (sunburning) UVR is quantified with the UV Index (UVI) derived from these measurements. UVI data show unprecedently large anomalies, occurring mostly between early March and mid‐April 2020. For several days, UVIs observed in 2020 exceeded measurements of previous years by up to 140%. Historical means were surpassed by more than six standard deviations at several locations in the Arctic. In northern Canada, the average UVI for March was about 75% larger than usual. UVIs in April 2020 were elevated on average by about 25% at all sites. However, absolute anomalies remained below 3.0 UVI units because the enhancements occurred during times when the solar elevation was still low.
2020
An overview of the uses of per- And polyfluoroalkyl substances (PFAS)
Per- and polyfluoroalkyl substances (PFAS) are of concern because of their high persistence (or that of their degradation products) and their impacts on human and environmental health that are known or can be deduced from some well-studied PFAS. Currently, many different PFAS (on the order of several thousands) are used in a wide range of applications, and there is no comprehensive source of information on the many individual substances and their functions in different applications. Here we provide a broad overview of many use categories where PFAS have been employed and for which function; we also specify which PFAS have been used and discuss the magnitude of the uses. Despite being non-exhaustive, our study clearly demonstrates that PFAS are used in almost all industry branches and many consumer products. In total, more than 200 use categories and subcategories are identified for more than 1400 individual PFAS. In addition to well-known categories such as textile impregnation, fire-fighting foam, and electroplating, the identified use categories also include many categories not described in the scientific literature, including PFAS in ammunition, climbing ropes, guitar strings, artificial turf, and soil remediation. We further discuss several use categories that may be prioritised for finding PFAS-free alternatives. Besides the detailed description of use categories, the present study also provides a list of the identified PFAS per use category, including their exact masses for future analytical studies aiming to identify additional PFAS.
2020
Validation of the TROPOspheric Monitoring Instrument (TROPOMI) surface UV radiation product
The TROPOspheric Monitoring Instrument (TROPOMI) onboard the Sentinel-5 Precursor (S5P) satellite was launched on 13 October 2017 to provide the atmospheric composition for atmosphere and climate research. The S5P is a Sun-synchronous polar-orbiting satellite providing global daily coverage. The TROPOMI swath is 2600 km wide, and the ground resolution for most data products is 7.2×3.5 km2 (5.6×3.5 km2 since 6 August 2019) at nadir. The Finnish Meteorological Institute (FMI) is responsible for the development of the TROPOMI UV algorithm and the processing of the TROPOMI surface ultraviolet (UV) radiation product which includes 36 UV parameters in total. Ground-based data from 25 sites located in arctic, subarctic, temperate, equatorial and Antarctic areas were used for validation of the TROPOMI overpass irradiance at 305, 310, 324 and 380 nm, overpass erythemally weighted dose rate/UV index, and erythemally weighted daily dose for the period from 1 January 2018 to 31 August 2019. The validation results showed that for most sites 60 %–80 % of TROPOMI data was within ±20 % of ground-based data for snow-free surface conditions. The median relative differences to ground-based measurements of TROPOMI snow-free surface daily doses were within ±10 % and ±5 % at two-thirds and at half of the sites, respectively. At several sites more than 90 % of cloud-free TROPOMI data was within ±20 % of ground-based measurements. Generally median relative differences between TROPOMI data and ground-based measurements were a little biased towards negative values (i.e. satellite data < ground-based measurement), but at high latitudes where non-homogeneous topography and albedo or snow conditions occurred, the negative bias was exceptionally high: from −30 % to −65 %. Positive biases of 10 %–15 % were also found for mountainous sites due to challenging topography. The TROPOMI surface UV radiation product includes quality flags to detect increased uncertainties in the data due to heterogeneous surface albedo and rough terrain, which can be used to filter the data retrieved under challenging conditions.
2020