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  • 1.
    Björkvald, Louise
    et al.
    Stockholm University, Faculty of Science, Department of Geology and Geochemistry. Geokemi.
    Laudon, Hjalmar
    Borg, Hans
    Department of Applied Environmental Science (ITM).
    Mörth, Carl-Magnus
    Stockholm University, Faculty of Science, Department of Geology and Geochemistry.
    Trace metals and sulphur isotopes in samll boreal streams: the influence of landscape type2008In: 2008 Ocean Sciences Meeting: From the watershed to the global ocean, 2008, p. 1-Conference paper (Refereed)
    Abstract [en]

    The transport of trace metals (TM) and dissolved organic carbon (DOC) from headwater streams to the sea is influenced by various landscape elements. Our focus was to investigate the influence of major landscape elements on observed concentrations of dissolved metals (e.g. As, Cd, Co, Fe, Pb), DOC, sulphate, and sulphur isotope composition in streams, north- eastern Sweden, a coastal region characterized by peat wetlands and coniferous forests.

    Stream water samples collected from 10 streams (0.13 to 67 km2) in a boreal stream network reveal that landscape type (i.e. coverage of wetland and forest) is significant for river chemistry. Streams with different catchment characteristics responded differently to hydrological episodes. In forested streams, concentrations of TM, Fe and DOC increased, while they decreased in wetland influenced streams. Furthermore, Fe and Pb correlated positively with wetland coverage. Moreover, significantly lower average sulphate concentrations, but higher isotope values, were observed in wetland streams.

    This study emphasises the importance of understanding stream water chemistry from a landscape perspective in order to identify potential environments where climate change may induce enhanced metal mobilization in the future.

  • 2.
    Borg, H
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Inverkan av kalkning på metaller i vattendrag. Redovisning av delprojekt 2b.B inom IKEU-utvärderingen 20082008Report (Other academic)
  • 3.
    Borg, H
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Wällstedt, T
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Inverkan av kalkning på metaller i sjöar. Redovisning av delprojekt 2a.4 inom IKEU-utvärderingen 20082008Report (Other academic)
  • 4.
    Borg, Hans
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Andrén,
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Sundbom,
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Wilander, A.
    Wällstedt,
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Episodförsurning - Underlag till Naturvårdsverkets handbok för kalkning av sjöar och vattendrag.2007Report (Other (popular science, discussion, etc.))
  • 5.
    Borg, Hans
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Sundbom, Marcus
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Long-term trends of water chemistry in mountain streams in Sweden - slow recovery from acidification2014In: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 11, no 1, p. 173-184Article in journal (Refereed)
    Abstract [en]

    The water chemistry of streams and precipitation in the province of Jamtland, northern Sweden has been monitored since the 1980s to study long-term trends, occurrence of acid episodes, and effects of liming. The acidity in precipitation increased in the 1970s, followed by a loss of acid neutralizing capacity (ANC) and low pH in the streams. Sulfur deposition began to decrease in the 1980s, until approximately 2000, after which the decrease levelled out. Stream water sulfate concentration followed the precipitation trend but decreased more slowly and since the late 1990s a subtle increase was observed. Sulfate concentrations in the snow typically have been higher than or equal to the stream sulfate levels. However, during the period of rapid deposition decrease and also since 2005 stream sulfate has sometimes exceeded snow sulfate, indicating desorption of stored soil sulfate, possibly because of climate-related changes in runoff routes through the soil profiles, following shorter periods of frost. From 1982 to 2000, total organic carbon (TOC) increased by approximately 0.1 mg L-1 yr(-1). The mean trends in sulfate and TOC from approximately 1990 until today were generally opposite. Acidic episodes with pH 4.0 at flow peaks occurred frequently in the unlimed streams, despite relatively well-buffered waters at baseflow. To evaluate the main causes for the loss of ANC during episodes, the changes in major ion concentrations during high flow episodes were evaluated. The most important factors contributing to ANC loss were dilution of base cations (Na+, K+, Ca2+, Mg2+), enrichment of organic anions and enrichment of sulfate. Wetland liming started in 1985 after which the earlier observed extreme peak values of iron, manganese and aluminium, did not reoccur. The studied area is remote from emission sources in Europe, but the critical load of acidity is still exceeded. The long-term recovery observed in the unlimed streams is thus slow, and severe acidic episodes still occur.

  • 6.
    Breitholtz, Magnus
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Näslund, Maria
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Strae, Daniel
    Borg, Hans
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Grabic, Roman
    Fick, Jerker
    An evaluation of free water surface wetlands as tertiary sewage water treatment of micro-pollutants2012In: Ecotoxicology and Environmental Safety, ISSN 0147-6513, E-ISSN 1090-2414, Vol. 78, p. 63-71Article in journal (Refereed)
    Abstract [en]

    Increased attention is currently directed towards potential negative effects of pharmaceuticals and other micro-pollutants discharged into the aquatic environment via municipal sewage water. A number of additional treatment technologies, such as ozonation, have therefore been suggested as promising tools for improving the removal efficiency of pharmaceuticals in existing Sewage Treatment Plants (STPs). Constructed wetlands are also capable of removing a variety of micro-pollutants, including some pharmaceuticals, and could hence be a resource efficient complement to more advanced treatment technologies. The purpose of the present study was therefore to increase the knowledge base concerning the potential use of constructed wetlands as a treatment step to reduce emissions of organic micro-pollutants from municipal sewage effluents. Under cold winter conditions, incoming and outgoing waters from four Swedish free water surface wetlands, operated as final treatment steps of sewage effluent from municipal STPs, were sampled and analyzed for levels of a set of 92 pharmaceuticals and 22 inorganic components as well as assessed using subchronic ecotoxicity tests with a macro-alga and a crustacean. Sixty-five pharmaceuticals were detected in the range from 1 ng L-1 to 7.6 mu g L-1 in incoming and outgoing waters from the four investigated wetlands. Although the sampling design used in the present study lacks the robustness of volume proportional to 24 h composite samples, the average estimated removal rates ranged from 42% to 52%, which correlates to previous published values. The effects observed in the ecotoxicity tests with the macro-alga (EC(50)s in the range of 7.5-46%) and the crustacean (LOECs in the range of 11.25-90%) could not be assigned to either pharmaceutical residues or metals, but in general showed that these treatment facilities release water with a relatively low toxic potential, comparable to water that has been treated with advanced tertiary treatments. From the present study it can be concluded that constructed wetlands may provide a complementary sewage treatment option, especially where other treatment is lacking today. To fully remove micro-pollutants from sewage effluent, however, other more advanced treatment technologies are likely needed.

  • 7.
    Edberg, F
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Wällstedt, T
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Borg, H
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Kalkningsavslut i Tyresta – utvärdering och komplettering av kemi och metaller i vatten och sediment2008Report (Other academic)
  • 8.
    Edberg, Frida
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Hägglund, Anna
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Wällstedt, Teresia
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Borg, Hans
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Holmström, Sara J. M.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Geochemistry of metals in a former uranium open pit mine – size fractionation of the water columnManuscript (preprint) (Other academic)
  • 9.
    Eklund, B
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Elfström, M.
    Borg, H
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    TBT originates from pleasure boats in Sweden in spite of firm restrictions.2008In: Open Environmental Sciences, Vol. 2, p. 124-132Article in journal (Refereed)
  • 10. Fölster, J.
    et al.
    Borg, H
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Holmgren, K.
    Framtidens nationella kalkningsuppföljning inom IKEU. Redovisning av delprojekt 5 inom IKEU-utvärderingen 20082008Report (Other academic)
  • 11. Gantner, Nikolaus
    et al.
    Muir, Derek C.
    Power, Michael
    Iqaluk, Deborah
    Reist, James D.
    Babaluk, John A.
    Meili, Markus
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Borg, Hans
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Hammar, Johan
    Michaud, Wendy
    Dempson, Brian
    Solomon, Keith R.
    MERCURY CONCENTRATIONS IN LANDLOCKED ARCTIC CHAR (SALVELINUS ALPINUS) FROM THE CANADIAN ARCTIC. PART II: INFLUENCE OF LAKE BIOTIC AND ABIOTIC CHARACTERISTICS ON GEOGRAPHIC TRENDS IN 27 POPULATIONS2010In: Environmental Toxicology and Chemistry, ISSN 0730-7268, E-ISSN 1552-8618, Vol. 29, no 3, p. 633-643Article in journal (Refereed)
    Abstract [en]

    Among-lake variation in mercury (Hg) concentrations in landlocked Arctic char was examined in 27 char populations from remote lakes across the Canadian Arctic. A total of 520 landlocked Arctic char were collected from 27 lakes, as well as sediments and surface water from a subset of lakes in 1999, 2002, and 2005 to 2007. Size, length, age, and trophic position (delta N-15) of individual char were determined and relationships with total Hg (THg) concentrations investigated, to identify a common covariate for adjustment using analysis of covariance (ANCOVA). A subset of 216 char from 24 populations was used for spatial comparison, after length-adjustment. The influence of trophic position and food web length and abiotic characteristics such as location, geomorphology, lake area, catchment area, catchment-to-lake area ratio of the lakes on adjusted THg concentrations in char muscle tissue were then evaluated. Arctic char from Amituk Lake (Cornwallis Island) had the highest Hg concentrations (1.31 mu g/g wet wt), while Tessisoak Lake (Labrador, 0.07 mu g/g wet wt) had the lowest. Concentrations of THg were positively correlated with size, delta N-15, and age, respectively, in 88, 71, and 58% of 24 char populations. Length and delta N-15 were correlated in 67% of 24 char populations. Food chain length did not explain the differences in length-adjusted THg concentrations in char. No relationships between adjusted THg concentrations in char and latitude or longitude were found, however, THg concentrations in char showed a positive correlation with catchment-to-lake area ratio. Furthermore, we conclude that inputs from the surrounding environment may influence THg concentrations, and will ultimately affect THg concentrations in char as a result of predicted climate-driven changes that may occur in Arctic lake watersheds. Environ. Toxicol. Chem. 2010; 29: 633-643.

  • 12. Gantner, Nikolaus
    et al.
    Power, Michael
    Iqaluk, Deborah
    Meili, Markus
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Borg, Hans
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Sundbom, Marcus
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Solomon, Keith R.
    Lawson, Greg
    Muir, Derek C.
    MERCURY CONCENTRATIONS IN LANDLOCKED ARCTIC CHAR (SALVELINUS ALPINUS) FROM THE CANADIAN ARCTIC. PART I: INSIGHTS FROM TROPHIC RELATIONSHIPS IN 18 LAKES2010In: Environmental Toxicology and Chemistry, ISSN 0730-7268, E-ISSN 1552-8618, Vol. 29, no 3, p. 621-632Article in journal (Refereed)
    Abstract [en]

    Concentrations of mercury (Hg) have increased slowly in landlocked Arctic char over a 10- to 15-year period in the Arctic. Fluxes of Hg to sediments also show increases in most Arctic lakes. Correlation of Hg with trophic level (TL) was used to investigate and compare biomagnification of Hg in food webs from lakes in the Canadian Arctic sampled from 2002 to 2007. Concentrations of Hg (total Hg and methylmercury [MeHg]) in food webs were compared across longitudinal and latitudinal gradients in relation to delta C-13 and delta N-15 in periphyton, zooplankton, benthic invertebrates, and Arctic char of varying size-classes. Trophic magnification factors (TMFs) were calculated for the food web in each lake and related to available physical and chemical characteristics of the lakes. The relative content of MeHg increased with trophic level from 4.3 to 12.2% in periphyton, 41 to 79% in zooplankton, 59 to 72% in insects, and 74 to 100% in juvenile and adult char. The delta C-13 signatures of adult char indicated coupling with benthic invertebrates. Cannibalism among char lengthened the food chain. Biomagnification was confirmed in all 18 lakes, with TMFs ranging from 3.5 +/- 1.1 to 64.3 +/- 0.8. Results indicate that TMFs and food chain length (FCL) are key factors in explaining interlake variability in biomagnification of [Hg] among different lakes. Environ. Toxicol. Chem. 2010; 29: 621-632. (C) 2009 SETAC

  • 13. Helander, B.
    et al.
    Axelsson, J.
    Borg, Hans
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Holm, Karin
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Bignert, A.
    Ingestion of lead from ammunition and lead concentrations in white-tailed sea eagles (Haliaeetus albicilla) in Sweden2009In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 407, no 21, p. 5555-5563Article in journal (Refereed)
    Abstract [en]

    In this study we show for the first time that lead poisoning from ammunition is a significant mortality factor for white-tailed sea eagle (WSE) (Holiaeetus albicilla) in Sweden. We analyzed 118 WSEs collected between 1981 and 2004 from which both liver and kidney samples could be taken. A total of 22% of all eagles examined had elevated (>6 mu g/g d.w.) lead concentrations, indicating exposure to leaded ammunition. and 14% of the individuals had either liver or kidney lead concentrations diagnostic of lethal lead poisoning (>20 mu g/g d.w.). Lead concentrations in liver and kidney were significantly correlated. In individuals with lead levels <6 mu g/g, concentrations were significantly higher in kidney than in liver; in individuals with lead levels >20 mu g/g, concentrations were significantly higher in liver. The lead isotope ratios indicate that the source of lead in individuals with lethal concentrations is different from that of individuals exhibiting background concentrations of lead (<6 mu g/g d.w.) There were no significant sex or age differences in lead concentrations. A study from the Baltic reported in principle no biomagnification of lead, but background lead concentrations in WSE liver in this study were still four to >10 times higher than concentrations reported for Baltic fish from the same time period. in contrast to other biota there was no decrease in lead concentrations in WSE over the study period. The proportion of lead poisoned WSE remained unchanged over the study period, including two years after a partial ban of lead shot was enforced in 2002 for shallow wetlands. The use of lead in ammunition poses a threat to all raptors potentially feeding on shot game or offal. The removal of offal from shot game and alternatives to leaded ammunition needs to be implemented in order to prevent mortality from lead in raptors and scavengers.

  • 14.
    Hoppe, Sabina
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Gustafsson, J. -P
    Borg, Hans
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Breitholtz, Magnus
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Evaluation of current copper bioavailability tools for soft freshwaters in Sweden2015In: Ecotoxicology and Environmental Safety, ISSN 0147-6513, E-ISSN 1090-2414, Vol. 114, p. 143-149Article in journal (Refereed)
    Abstract [en]

    The Water Framework Directive (WFD) in Europe calls for an improved aquatic ecological status. Biotic ligand models (ELM) have been suggested as a possible tool assisting in the regulatory process. The aim of this study was therefore to investigate the applicability of ELM under the WFD to set environmental quality standards (EQS), in particular regarding copper in Swedish freshwaters of which many are softer than those used for model calibration. Three different BLMs, one acute and two chronic, were applied to water chemistry data from 926 lakes and 51 rivers (1530 data entries) and evaluated with respect to their calibration range for input parameters. In addition, the predicted no-effect concentration (PNEC) for copper was calculated. From the 1530 data entries, 750 ended up outside of the BLM calibration range, when looking at the chemical parameters Ca2+, alkalinity, pH and DOC, primarily due to low carbonate alkalinity. Furthermore, the calculated Cu PNECs were higher than the suggested Swedish limit for Cu (4 mu g L-1) in surface waters for 98% and 99% of the cases concerning lakes and rivers, respectively. To conclude, our findings show that water chemical characteristics outside of the calibration ranges are quite common in Sweden and that the investigated models differ in how they calculate toxicity concerning Cu under these conditions. As a consequence, additional work is required to validate the BLMs by use of bioassays with representative species of soft waters. Such results will show if these models can be used outside of their calibration ranges and also which of the models that gives the most reliable results.

  • 15.
    Hoppe, Sabina
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Sundbom, Marcus
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Borg, Hans
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Breitholtz, Magnus
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Predictions of Cu toxicity in three aquatic species using bioavailability tools in four Swedish soft freshwaters2015In: Environmental Sciences Europe, ISSN 2190-4707, E-ISSN 2190-4715, Vol. 27, no 25Article in journal (Refereed)
    Abstract [en]

    Background

    The EU member countries are currently implementing the Water Framework Directive to promote better water quality and overview of their waters. The directive recommends the usage of bioavailability tools, such as biotic ligand models (BLM), for setting environmental quality standards (EQS) for metals. These models are mainly calibrated towards a water chemistry found in the south central parts of Europe. However, freshwater chemistry in Scandinavia often has higher levels of DOC (dissolved organic carbon), Fe and Al combined with low pH compared to the central parts of Europe. In this study, copper (Cu) toxicities derived by two different BLM software were compared to bioassay-derived toxicity for Pseudokirchneriella subcapitata, Daphnia magna and D. pulex in four Swedish soft water lakes.

    Results

    A significant under- and over prediction between measured and BLM calculated toxicity was found; for P. subcapitata in three of the four lakes and for the daphnids in two of the four lakes. The bioassay toxicity showed the strongest relationship with Fe concentrations and DOC. Furthermore, DOC was the best predictor of BLM results, manifested as positive relationships with calculated LC50 and NOEC for P. subcapitata and D. magna, respectively.

    Conclusion

    Results from this study indicate that the two investigated BLM softwares have difficulties calculating Cu toxicity, foremost concerning the algae. The analyses made suggest that there are different chemical properties affecting the calculated toxicity as compared to the measured toxicity. We recommend that tests including Al, Fe and DOC properties as BLM input parameters should be conducted. This to observe if a better consensus between calculated and measured toxicity can be established.

  • 16.
    Humborg, Cristoph
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Mörth, Carl Magnus
    Stockholm University, Faculty of Science, Department of Geology and Geochemistry.
    Sundbom, Marcus
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Borg, Hans
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Blenckner, Thorsten
    Stockholm University, Stockholm Resilience Centre, Baltic Nest Institute.
    Giesler, R.
    Ittekkot, V.
    CO2 supersaturation along the aquatic conduit in Swedish watersheds as constrained by terrestrial respiration, aquatic respiration and weathering2010In: Global Change Biology, ISSN 1354-1013, E-ISSN 1365-2486, Vol. 6, no 7, p. 1966-1978Article in journal (Refereed)
    Abstract [en]

    We tested the hypothesis that CO2 supersaturation along the aquatic conduit over Sweden can be explained by processes other than aquatic respiration. A first generalized-additive model (GAM) analysis evaluating the relationships between single water chemistry variables and pCO(2) in lakes and streams revealed that water chemistry variables typical for groundwater input, e.g., dissolved silicate (DSi) and Mg2+ had explanatory power similar to total organic carbon (TOC). Further GAM analyses on various lake size classes and stream orders corroborated the slightly higher explanatory power for DSi in lakes and Mg2+ for streams compared with TOC. Both DSi and TOC explained 22-46% of the pCO(2) variability in various lake classes (0.01-> 100 km2) and Mg2+ and TOC explained 11-41% of the pCO(2) variability in the various stream orders. This suggests that aquatic pCO(2) has a strong groundwater signature. Terrestrial respiration is a significant source of the observed supersaturation and we may assume that both terrestrial respiration and aquatic respiration contributed equally to pCO(2) efflux. pCO(2) and TOC concentrations decreased with lake size suggesting that the longer water residence time allow greater equilibration of CO2 with the atmosphere and in-lake mineralization of TOC. For streams, we observed a decreasing trend in pCO(2) with stream orders between 3 and 6. We calculated the total CO2 efflux from all Swedish lakes and streams to be 2.58 Tg C yr-1. Our analyses also demonstrated that 0.70 Tg C yr-1 are exported to the ocean by Swedish watersheds as HCO3- and CO(3)2- of which about 0.56 Tg C yr-1 is also a residual from terrestrial respiration and constitute a long-term sink for atmospheric CO2. Taking all dissolved inorganic carbon (DIC) fluxes along the aquatic conduit into account will lower the estimated net ecosystem C exchange (NEE) by 2.02 Tg C yr-1, which corresponds to 10% of the NEE in Sweden.

  • 17. Sjöstedt, C.
    et al.
    Wallstedt, T.
    Gustafsson, J.P.
    Borg, Hans
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Speciation of aluminium, arsenic and molybdenum in excessively limed lakes2009In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 407, no 18, p. 5119-5127Article in journal (Refereed)
    Abstract [en]

    The possible existence of the potentially toxic oxyanions of Al (AI(OH)(4)(-)). As (HAsO42-), and Mo (MoO42-) was examined in excessively limed lakes. In-situ dialysis (MWCO 1 kDa) was performed in the surface and bottom waters of two excessively limed lakes (pH 7.1-7.7) and one acidic lake (pH similar to 5.4). The dialysable metal concentrations were compared to the equilibrium distribution of species as calculated with the geochemical code Visual MINTEQ incorporating the CD-MUSIC and Stockholm Humic models for complexation onto colloidal ferrihydrite and dissolved organic matter. Arsenic and molybdenum in the excessively limed lakes were to a large extent present in the dialysable fraction (79% and 92% respectively). They were calculated to exist as free or adsorbed oxyanions. Most of the Al was observed to reside in the colloidal fraction (51-82%). In agreement with this, model predictions indicated aluminium to be present mostly as colloids or bound to dissolved organic matter. Only a small fraction was modelled as AI(OH)(4)(-) ions. In most cases, modelled values were in agreement with the dialysis results. The free concentrations of the three oxyanions were mostly low compared to toxic levels.

  • 18. Sjöstedt, Carin
    et al.
    Persson, Ingmar
    Hesterberg, Dean
    Kleja, Dan Berggren
    Borg, Hans
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Gustafsson, Jon Petter
    Iron speciation in soft-water lakes and soils as determined by EXAFS spectroscopy and geochemical modelling2013In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 105, p. 172-186Article in journal (Refereed)
    Abstract [en]

    Complexation of iron by organic matter can potentially compete with toxic metals for binding sites. Iron(III) forms both monomeric and di/trimeric complexes with fulvic and humic acids, but the nature and extent of complexation with natural organic matter samples from soft-water lakes has not been extensively studied. The aim of this study was to determine the coordination of iron in complexes with organic matter in two soft-water lakes and in the surrounding Oe soil horizons. Iron K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy was performed on particles and large colloids (>0.45 mu m) collected by in-line pre-filtration, and on smaller colloids isolated both on an AGMP-1 anion-exchange column and by concentration using 1000 Da ultrafiltration. The results showed that iron(III) was mainly present in monomeric complexes with organic matter, both in the lake water smaller colloids and in the soil samples. Evidence for iron(III) (hydr)oxides was found for the lake particles, in the ultrafiltration retentates, and in some of the soils. Overall, the results suggest that complexation of iron(III) to organic matter prevents hydrolysis into polymeric forms. Strong complexation of iron(III) would lead to competition with other metals for organic-matter binding sites.

  • 19. Skjelkvåle, B.L.
    et al.
    Borg, Hans
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Hindar, A.
    Wilander, A.
    Large scale patterns of chemical recovery in lakes in Norway and Sweden: Importance of seasalt episodes and changes in dissolved organic carbon2007In: Appl Geochem, Vol. 22, p. 1174-1180Article in journal (Refereed)
  • 20.
    Stiernström, Sara
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Enell, A.
    Wik, O.
    Borg, Hans
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Breitholtz, Magnus
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    An ecotoxicological evaluation of aged bottom ash for use in constructions2014In: Waste Management, ISSN 0956-053X, E-ISSN 1879-2456, Vol. 34, no 1, p. 86-92Article in journal (Refereed)
    Abstract [en]

    Municipal and Industrial Solid Waste Incineration (MISWI) bottom ash is mainly deposited in landfills, but natural resources and energy could be saved if these ash materials would be used in geotechnical constructions. To enable such usage, knowledge is needed on their potential environmental impact. The aim of this study was to evaluate the ecotoxicity of leachates from MISWI bottom ash, aged for five years, in an environmental relevant way using a sequential batch leaching method at the Liquid/Solid-ratio interval 1-3, and to test the leachates in a (sub)chronic ecotoxicity test. Also, the leachates were characterized chemically and with the technique of diffusive gradients in thin films (DGTs). By comparing established ecotoxicity data for each element with chemically analysed and labile concentrations in the leachates, potentially problematic elements were identified by calculating Hazard Quotients (HQ). Overall, our results show that the ecotoxicity was in general low and decreased with increased leaching. A strong correspondence between calculated HQs and observed toxicity over the full L/S range was observed for K. However, K will likely not be problematic from a long-term environmental perspective when using the ash, since it is a naturally occurring essential macro element which is not classified as ecotoxic in the chemical legislation. Although Cu was measured in total concentrations close to where a toxic response is expected, even at L/S 3, the DGT-analysis showed that less than 50% was present in a labile fraction, indicating that Cu is complexed by organic ligands which reduce its bioavailability.

  • 21.
    Sundbom,
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Andrén,
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Borg, Hans
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Edberg, Frida
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Persson, G.
    Wällstedt,
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Kalkningsavslut - Underlag till Naturvårdsverkets handbok för kalkning av sjöar och vattendrag.2007Report (Other (popular science, discussion, etc.))
  • 22. Wallstedt, T.
    et al.
    Edberg, Frida
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Borg, Hans
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Long-term water chemical trends in two Swedish lakes after termination of liming2009In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 407, no 11, p. 3554-3562Article in journal (Refereed)
    Abstract [en]

    Lime treatment has been extensively used as a remedial measure against acidification of surface waters. In view of the decreasing acid deposition, the possible consequences of a termination of liming are discussed intensively in Sweden. This paper presents the results of the first study of long-term effects of termination of liming. The temporal trends in water chemistry were studied in two lakes after termination of liming, in a still-limed lake and in an unlimed reference lake. The lime treatment was intentionally stopped in order to evaluate the effects on water chemistry and biota. After the last liming, pH decreased steadily in both reacidifying takes until annual mean values stabilised around 5.5-6.0 and 6.2-6.5 respectively. ANC and concentrations of non-marine Ca + Mg decreased after the termination of liming. The decreasing pH resulted in increasing trends of inorganic Al (Al-i), which during recent years exceeded the lowest known effect level for fish on several occasions. This indicates that the lime treatment may have been terminated to early from an ecological perspective and with respect to the critical load of acidifying substances during the study period. However, during the same time, non-marine sulphate decreased in all lakes in the study and pH and ANC increased in the unlimed reference lake.

  • 23.
    Wällstedt, T
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Borg, H
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Meili, M
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Mörth, C.M.
    Influence of liming on metal sequestration in lake sediments over recent decades.2008In: Sci. Tot. Environ., Vol. 407, p. 405-417Article in journal (Refereed)
1 - 23 of 23
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