| 1. |
- Denby, B. R., et al.
(författare)
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Road salt emissions : A comparison of measurements and modelling using the NORTRIP road dust emission model
- 2016
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Ingår i: Atmospheric Environment. - : Elsevier Ltd. - 1352-2310 .- 1873-2844. ; 141, s. 508-522
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Tidskriftsartikel (refereegranskat)abstract
- De-icing of road surfaces is necessary in many countries during winter to improve vehicle traction. Large amounts of salt, most often sodium chloride, are applied every year. Most of this salt is removed through drainage or traffic spray processes but a certain amount may be suspended, after drying of the road surface, into the air and will contribute to the concentration of particulate matter. Though some measurements of salt concentrations are available near roads, the link between road maintenance salting activities and observed concentrations of salt in ambient air is yet to be quantified. In this study the NORTRIP road dust emission model, which estimates the emissions of both dust and salt from the road surface, is applied at five sites in four Nordic countries for ten separate winter periods where daily mean ambient air measurements of salt concentrations are available. The model is capable of reproducing many of the salt emission episodes, both in time and intensity, but also fails on other occasions. The observed mean concentration of salt in PM10, over all ten datasets, is 4.2 μg/m3 and the modelled mean is 2.8 μg/m3, giving a fractional bias of −0.38. The RMSE of the mean concentrations, over all 10 datasets, is 2.9 μg/m3 with an average R2 of 0.28. The mean concentration of salt is similar to the mean exhaust contribution during the winter periods of 2.6 μg/m3. The contribution of salt to the kerbside winter mean PM10 concentration is estimated to increase by 4.1 ± 3.4 μg/m3 for every kg/m2 of salt applied on the road surface during the winter season. Additional sensitivity studies showed that the accurate logging of salt applications is a prerequisite for predicting salt emissions, as well as good quality data on precipitation. It also highlights the need for more simultaneous measurements of salt loading together with ambient air concentrations to help improve model parameterisations of salt and moisture removal processes. © 2016 The Authors
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| 2. |
- Wrange, Anna-Lisa, et al.
(författare)
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Monitoring biofouling as a management tool for reducing toxic antifouling practices in the Baltic Sea
- 2020
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Ingår i: Journal of Environmental Management. - : Academic Press. - 0301-4797 .- 1095-8630. ; 264
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Tidskriftsartikel (refereegranskat)abstract
- Over two million leisure boats use the coastal areas of the Baltic Sea for recreational purposes. The majority of these boats are painted with toxic antifouling paints that release biocides into the coastal ecosystems and negatively impact non-targeted species. Regulations concerning the use of antifouling paints differ dramatically between countries bordering the Baltic Sea and most of them lack the support of biological data. In the present study, we collected data on biofouling in 17 marinas along the Baltic Sea coast during three consecutive boating seasons (May–October 2014, 2015 and 2016). In this context, we compared different monitoring strategies and developed a fouling index (FI) to characterise marinas according to the recorded biofouling abundance and type (defined according to the hardness and strength of attachment to the substrate). Lower FI values, i.e. softer and/or less abundant biofouling, were consistently observed in marinas in the northern Baltic Sea. The decrease in FI from the south-western to the northern Baltic Sea was partially explained by the concomitant decrease in salinity. Nevertheless, most of the observed changes in biofouling seemed to be determined by local factors and inter-annual variability, which emphasizes the necessity for systematic monitoring of biofouling by end-users and/or authorities for the effective implementation of non-toxic antifouling alternatives in marinas. Based on the obtained results, we discuss how monitoring programs and other related measures can be used to support adaptive management strategies towards more sustainable antifouling practices in the Baltic Sea. © 2020 The Authors
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| 3. |
- Drake, Henrik, et al.
(författare)
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Extreme fractionation and micro-scale variation of sulphur isotopes during bacterial sulphate reduction in deep groundwater systems
- 2015
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Ingår i: Geochimica Et Cosmochimica Acta. - : Elsevier BV. - 0016-7037 .- 1872-9533. ; 161, s. 1-18
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Tidskriftsartikel (refereegranskat)abstract
- This study conducted at the Aspo Hard Rock Laboratory, SE Sweden, determines the extent and mechanisms of sulphur-isotope fractionation in permanently reducing groundwater in fractured crystalline rock. Two boreholes > 400 m below the ground surface were investigated. In the 17-year-old boreholes, the Al instrumentation pipes had corroded locally (i.e., Al[oxy] hydroxides had formed) and minerals (i.e., pyrite, iron monosulphide, and calcite) had precipitated on various parts on the equipment. By chemically and isotopically comparing the precipitates on the withdrawn instrumentation and the borehole waters, we gained new insight into the dynamics of sulphate reduction, sulphide precipitation, and sulphur-isotope fractionation in deep-seated crystalline-rock settings. An astonishing feature of the pyrite is its huge variability in delta S-34, which can exceed 100 parts per thousand in total (i.e., -47.2 to +53.3 parts per thousand) and 60 parts per thousand over 50 mu m of growth in a single crystal. The values at the low end of the range are up to 71 parts per thousand lower than measured in the dissolved sulphate in the water (20-30 parts per thousand), which is larger than the maximum difference reported between sulphate and sulphide in pure-culture experiments (66 parts per thousand) but within the range reported from natural sedimentary settings. Although single-step reduction seems likely, further studies are needed to rule out the effects of possible S disproportionation. The values at the high end of the range (i.e., high delta S-34(py)) are much higher than could be produced from the measured sulphate under any biogeochemical conditions. This strongly suggests the development of closed-system conditions near the growing pyrite, i.e., the rate of sulphate reduction exceeds the rate of sulphate diffusion in the local fluid near the pyrite, causing the local aqueous phase (and thus the forming pyrite) to become successively enriched in heavy S (S-34). Consequently, the delta S-34 values of the forming pyrite become exceptionally high and strongly decoupled from the delta S-34 values of the sulphate in the bulk fluid. The Al-(oxy) hydroxide and calcite precipitates are explained by a combination of deposit and galvanic corrosion initiated by Al corrosion by H2S produced by sulphate-reducing microorganisms. (C) 2015 Elsevier Ltd. All rights reserved.
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| 4. |
- Eveborn, David, 1978-, et al.
(författare)
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Phosphorus in soil treatment systems : accumulation and mobility
- 2014
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Ingår i: Water Research. - : Elsevier. - 0043-1354 .- 1879-2448. ; 64, s. 42-52
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Tidskriftsartikel (refereegranskat)abstract
- In several western countries, septic tanks with subsequent soil treatment systems (STS) are a common treatment technique for domestic wastewater in rural areas. However the suitability of STS (especially relatively close to surface waters) can be questioned since the discharge of phosphorus (P) from such effluents is not well known. In this study, six STS in Sweden (11 to 28 years old) were investigated by means of batch and column experiments on samples taken from the unsaturated subsoil beneath the distribution pipes. At all sites the wastewater had clearly influenced the soil. This was observed through decreased pH, increased amounts of oxalate extractable metals and altered P sorption properties. The amount of accumulated P in the STS (defined as the amount of total P in the STS samples minus the amount of total P in unused soil samples) were found to be between 0.32 and 0.87 kg m-3, which in most cases was just a small fraction of the estimated P load (< 30%). Column studies revealed that remarkably high P concentrations (up to 6 mg L-1) were leached from the material when deionized water was applied. However, the response to deionized water varied between the sites. The affinity for P in the soils was well correlated to the amount of oxalate-extractable aluminium (as evidenced by a strong relationship between oxalate-extractable Al and oxalate-extractable P) and generally soils with high content of oxalate extractable Al was also less vulnerable to P leakage.
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| 5. |
- Lundberg, Joacim, 1991-, et al.
(författare)
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Wet Dust Sampler : a Sampling Method for Road Dust Quantification and Analyses
- 2019
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Ingår i: Water, Air and Soil Pollution. - : Springer. - 0049-6979 .- 1573-2932. ; 230:8
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Tidskriftsartikel (refereegranskat)abstract
- In northern countries, the climate, and consequently the use of studded tyres and winter traction sanding, causes accumulation of road dust over winter and spring, resulting in high PM10 concentrations during springtime dusting events. To quantify the dust at the road surface, a method—the wet dust sampler (WDS)—was developed allowing repeatable sampling also under wet and snowy conditions. The principle of operation is flushing high-pressurised water over a defined surface area and transferring the dust laden water into a container for further analyses.In this paper, the latest version of the WSD is presented together with an evaluation of its performance. To evaluate the WDS, the ejected water amount was measured, as well as water losses in different parts of the sampling system, together with indicative dust measurement using turbidity as a proxy for dust concentration. The results show that the WDS, when accounting for all losses, have a predictable and repeatable water performance, with no impact on performance based on the variety of asphalt surface types included in this study, given undamaged surfaces. The largest loss was found to be water retained on the surface, and the dust measurements imply that this might not have as large impact on the sampled dust as could be expected. A theoretical particle mass balance shows small particle losses, while field measurements show higher losses. Several tests are suggested to validate and improve on the mass balances. Finally, the WDS is found to perform well and is able to contribute to further knowledge regarding road dust implications for air pollution.
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| 6. |
- Campeau, Audrey, et al.
(författare)
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Current forest carbon fixation fuels stream CO 2 emissions
- 2019
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Ingår i: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- Stream CO 2 emissions contribute significantly to atmospheric climate forcing. While there are strong indications that groundwater inputs sustain these emissions, the specific biogeochemical pathways and timescales involved in this lateral CO 2 export are still obscure. Here, via an extensive radiocarbon ( 14 C) characterisation of CO 2 and DOC in stream water and its groundwater sources in an old-growth boreal forest, we demonstrate that the 14 C-CO 2 is consistently in tune with the current atmospheric 14 C-CO 2 level and shows little association with the 14 C-DOC in the same waters. Our findings thus indicate that stream CO 2 emissions act as a shortcut that returns CO 2 recently fixed by the forest vegetation to the atmosphere. Our results expose a positive feedback mechanism within the C budget of forested catchments, where stream CO 2 emissions will be highly sensitive to changes in forest C allocation patterns associated with climate and land-use changes. © 2019, The Author(s).
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| 7. |
- Lagerström, Maria, 1986, et al.
(författare)
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In situ release rates of Cu and Zn from commercial antifouling paints at different salinities
- 2018
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Ingår i: Marine Pollution Bulletin. - : Elsevier BV. - 0025-326X .- 1879-3363. ; 127, s. 289-296
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Tidskriftsartikel (refereegranskat)abstract
- Antifouling paints are environmentally risk assessed based on their biocidal release rates to the water phase. In situ release rates of copper (Cu) and zinc (Zn) were derived for five commercial paints in two recreational marinas with different salinities (5 and 14 PSU) using an X-Ray Fluorescence spectrometer (XRF). Salinity was found to significantly affect the Cu release, with twice the amount of Cu released at the higher salinity, while its influence on the Zn release was paint-specific. Site-specific release rates for water bodies with salinity gradients, e.g. the Baltic Sea, are therefore necessary for more realistic risk assessments of antifouling paints. Furthermore, the in situ release rates were up to 8 times higher than those generated using standardized laboratory or calculation methods. The environmental risk assessment repeated with the field release rates concludes that it is questionable whether the studied products should be allowed on the Swedish market.
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| 8. |
- Ivarsson, Magnus, 1975-, et al.
(författare)
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Intricate tunnels in garnets from soils and rivere sediments in Thailand - possible endolithic microborings
- 2018
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Ingår i: PLOS ONE. - Niagara University, USA : Public Library of Science (PLoS). - 1932-6203. ; 13:8
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Tidskriftsartikel (refereegranskat)abstract
- Garnets from disparate geographical environments and origins such as oxidized soils and river sediments in Thailand host intricate systems of microsized tunnels that significantly decrease the quality and value of the garnets as gems. The origin of such tunneling has previously been attributed to abiotic processes. Here we present physical and chemical remains of endolithic microorganisms within the tunnels and discuss a probable biological origin of the tunnels. Extensive investigations with synchrotron-radiation X-ray tomographic microscopy (SRXTM) reveal morphological indications of biogenicity that further support a euendolithic interpretation. We suggest that the production of the tunnels was initiated by a combination of abiotic and biological processes, and that at later stages biological processes came to dominate. In environments such as river sediments and oxidized soils garnets are among the few remaining sources of bio-available Fe2+, thus it is likely that microbially mediated boring of the garnets has trophic reasons. Whatever the reason for garnet boring, the tunnel system represents a new endolithic habitat in a hard silicate mineral otherwise known to be resistant to abrasion and chemical attack.
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| 9. |
- Egeskog, Andrea, 1981, et al.
(författare)
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Actions and opinions of Brazilian farmers who shift to sugarcane : an interview-based assessment with discussion of implications for land-use change
- 2016
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Ingår i: Land use policy. - Kidlington : Elsevier. - 0264-8377 .- 1873-5754. ; 57, s. 594-604
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Tidskriftsartikel (refereegranskat)abstract
- Sugarcane ethanol systems can deliver large greenhouse gas emissions savings if emissions associated with land-use change are kept low. This qualitative study documents and analyzes actions and opinions among Brazilian farmers who shift to sugarcane production. Semi-structured interviews were held with 28 actors associated with sugarcane production in three different regions: one traditional sugarcane region and two regions where sugarcane is currently expanding. Most farmers considered sugarcane a land diversification option with relatively low economic risk, although higher risk than their previous land use. Beef production was considered a low-risk option, but less profitable than sugarcane. In conjunction with converting part of their land to sugarcane, most farmers maintained and further intensified their previous agricultural activity, often beef production. Several farmers invested in expanded production in other regions with relatively low land prices. Very few farmers in the expansion regions shifted all their land from the former, less profitable, use to sugarcane. Very few farmers in this study had deforested any land in connection with changes made when shifting to sugarcane. The respondents understand "environmental friendliness" as compliance with the relevant legislation, especially the Brazilian Forest Act, which is also a requirement for delivering sugarcane to the mills. Indirect land-use change is not a concern for the interviewed farmers, and conversion of forests and other native vegetation into sugarcane plantations is uncontroversial if legal. We derive hypotheses regarding farmers' actions and opinions from our results. These hypotheses aim to contribute to better understanding of what takes place in conjunction with expansion of sugarcane and can, when tested further, be of use in developing, e.g., policies for iLUC-free biofuel production.
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| 10. |
- Gren, Johan, et al.
(författare)
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Molecular and microstructural inventory of an isolated fossil bird feather from the Eocene Fur Formation of Denmark
- 2017
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Ingår i: Palaeontology. - : Blackwell Publishing. - 0031-0239 .- 1475-4983. ; 60:1, s. 73-90
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Tidskriftsartikel (refereegranskat)abstract
- An isolated, yet virtually intact contour feather (FUM-1980) from the lower Eocene Fur Formation of Denmark was analysed using multiple imaging and molecular techniques, including field emission gun scanning electron microscopy (FEG-SEM), X-ray absorption spectroscopy and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Additionally, synchrotron radiation X-ray tomographic microscopy (SRXTM) was employed in order to produce a digital reconstruction of the fossil. Under FEG-SEM, the proximal, plumulaceous part of the feather revealed masses of ovoid microstructures, about 1.7 μm long and 0.5 μm wide. Microbodies in the distal, pennaceous portion were substantially smaller (averaging 0.9 × 0.2 μm), highly elongate, and more densely packed. Generally, the microbodies in both the plumulaceous and pennaceous segments were aligned along the barbs and located within shallow depressions on the exposed surfaces. Biomarkers consistent with animal eumelanins were co-localized with the microstructures, to suggest that they represent remnant eumelanosomes (i.e. eumelanin-housing cellular organelles). Additionally, ToF-SIMS analysis revealed the presence of sulfur-containing organics – potentially indicative of pheomelanins – associated with eumelanin-like compounds. However, since there was no correlation between melanosome morphology and sulfur content, we conclude these molecular structures derive from diagenetically incorporated sulfur rather than pheomelanin. Melanosomes corresponding roughly in both size and morphology with those in the proximal part of FUM-1980 are known from contour feathers of extant parrots (Psittaciformes), an avian clade that has previously been reported from the Fur Formation.
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