| 1. |
- Augustsson, Anna, et al.
(författare)
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High metal reactivity and environmental risks at a site contaminated by glass waste
- 2016
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 154, s. 434-443
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Tidskriftsartikel (refereegranskat)abstract
- This study addresses the reactivity and risks of metals (Ba, Cd, Co, Cr, Cu, Ni, Pb, Zn, As and Sb) at a Swedish site with large glass waste deposits. Old glassworks sites typically have high total metal concentrations, but as the metals are mainly bound within the glass waste and considered relatively inert, environmental investigations at these kinds of sites are limited. In this study, soil and landfill samples were subjected to a sequential chemical extraction procedure. Data from batch leaching tests and groundwater upstream and downstream of the waste deposits were also interpreted. The sequential extraction revealed that metals in <2 mm soil/waste samples were largely associated with geochemically active fractions, indicating that metals are released from pristine glass and subsequently largely retained in the surrounding soil and/or on secondary mineral coatings on fine glass particles. From the approximately 12,000 m(3) of coarse glass waste at the site, almost 4000 kg of Pb is estimated to have been lost through corrosion, which, however, corresponds to only a small portion of the total amount of Pb in the waste. Metal sorption within the waste deposits or in underlying soil layers is supported by fairly low metal concentrations in groundwater. However, elevated concentrations in downstream groundwater and in leachates of batch leaching tests were observed for several metals, indicating on-going leaching. Taken together, the high metal concentrations in geochemically active forms and the high amounts of as yet uncorroded metal-rich glass, indicate considerable risks to human health and the environment.
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| 2. |
- Berggren Kleja, Dan
(författare)
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Old carbon in young fine roots in boreal forests
- 2015
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Ingår i: Biogeochemistry. - : Springer Science and Business Media LLC. - 0168-2563 .- 1573-515X. ; 125, s. 37-46
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Tidskriftsartikel (refereegranskat)abstract
- A large proportion of the soil carbon (C) in boreal forests originates from roots and ectomycorrhizal fungi, and accurate quantification of fine-root litter production is needed. Methods for determination of root turnover have been under debate in recent years. Two recently used methods-radiocarbon (C-14) dating and use of minirhizotrons (MR)-have yielded different results. This has been attributed to analysis of different roots by use of these methods. At Flakaliden, northern Sweden, in a long-term soil warming and irrigation experiment, we compared MR lifespan with the C-14-derived age of fine roots from soil cores of the same root diameter class. We also determined the C-14-derived age of ingrowth core roots of Norway spruce. The median lifespan of fine roots around MR tubes installed 15 years previously was shorter than 2.5 years whereas the C-14-derived age of the fine roots from soil cores varied from recently grown to 14 years. Correspondingly, the age of C-14 in fine roots harvested from ingrowth cores installed in soil 3 months previously was between 1 and 20 years. Thus, cellulose in these roots contained older C-14 than is possible from photosynthesis during the time of cellulose formation. By investigating whether the age of Norway spruce and Scots pine seedlings was less than their root C-14-derived age, we tested the possibility of root C originating from soil uptake. This was found to be unlikely, because fine roots of four and eight-year-old seedlings had C-14 that was dated to be as old as or younger than the seedlings. We propose that further effort is required to identify the ecological conditions leading to root growth utilization of stored or recycled C.
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| 3. |
- Berggren Kleja, Dan, et al.
(författare)
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Silver(I) Binding Properties of Organic Soil Materials Are Different from Those of Isolated Humic Substances
- 2016
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 50:14, s. 7453-7460
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Tidskriftsartikel (refereegranskat)abstract
- The solubility of silver(I) in many soils is controlled by complexation reactions with organic matter. In this work we have compared the ability of isolated humic and fulvic acids to bind silver(I) with that of mor and peat materials. One new data set for Suwannee River Fulvic Acid was produced, which was consistent with published data sets for isolated fulvic and humic acids. The ability of soil materials to bind silver(I) was studied as a function of pH in the range 2.5-5.0, at a wide range of silver(I)-to-soil ratios (10(-4.2) - 10(-1.9) mol kg(-1)). By calibrating the Stockholm Humic Model on the humic and fulvic acids data sets, we showed that binding of silver(I) to both types of soil materials was much stronger (up to 2 orders of magnitude) than predicted from the silver(I) binding properties of the isolated humic materials. Thus, the approach taken for many other metals, that is, to model solubility in soils by using metal and proton binding parameters derived from isolated humic and fulvic acids, cannot be used for silver(I). One possible explanation for the discrepancy could be that silver(I) predominately interacted with various biomolecules in the soil samples, instead of humic- and fulvic-acid type materials.
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| 4. |
- Campos Pereira, H., et al.
(författare)
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Sorption of perfluoroalkyl substances (PFASs) to an organic soil horizon – Effect of cation composition and pH
- 2018
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 207, s. 183-191
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Tidskriftsartikel (refereegranskat)abstract
- Accurate prediction of the sorption of perfluoroalkyl substances (PFASs) in soils is essential for environmental risk assessment. We investigated the effect of solution pH and calculated soil organic matter (SOM) net charge on the sorption of 14 PFASs onto an organic soil as a function of pH and added concentrations of Al3+, Ca2+ and Na+. Often, the organic C-normalized partitioning coefficients (KOC) showed a negative relationship to both pH (Δlog KOC/ΔpH = −0.32 ± 0.11 log units) and the SOM bulk net negative charge (Δlog KOC = −1.41 ± 0.40 per log unit molc g−1). Moreover, perfluorosulfonic acids (PFSAs) sorbed more strongly than perfluorocarboxylic acids (PFCAs) and the PFAS sorption increased with increasing perfluorocarbon chain length with 0.60 and 0.83 log KOC units per CF2 moiety for C3–C10 PFCAs and C4, C6, and C8 PFSAs, respectively. The effects of cation treatment and SOM bulk net charge were evident for many PFASs with low to moderate sorption (C5–C8 PFCAs and C6 PFSA). However for the most strongly sorbing and most long-chained PFASs (C9–C11 and C13 PFCAs, C8 PFSA and perfluorooctane sulfonamide (FOSA)), smaller effects of cations were seen, and instead sorption was more strongly related to the pH value. This suggests that the most long-chained PFASs, similar to other hydrophobic organic compounds, are preferentially sorbed to the highly condensed domains of the humin fraction, while shorter-chained PFASs are bound to a larger extent to humic and fulvic acid, where cation effects are significant.
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| 5. |
- Cornelis, Geert, et al.
(författare)
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Solubility and transport of Cr(III) in a historically contaminated soil – Evidence of a rapidly reacting dimeric Cr(III) organic matter complex
- 2017
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 189, s. 709-716
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Tidskriftsartikel (refereegranskat)abstract
- Chromium is a common soil contaminant and, although it has been studied widely, questions about its speciation and dissolutions kinetics remain unanswered. We combined information from an irrigation experiment performed with intact soil columns with data from batch experiments to evaluate solubility and mobilization mechanisms of Cr(III) in a historically contaminated soil (>65 years). Particulate and colloidal Cr(III) forms dominated transport in this soil, but their concentrations were independent of irrigation intensity (2-20 mm h(-1)). Extended X-ray absorption fine structure (EXAFS) measurements indicated that Cr(III) associated with colloids and particles, and with the solid phase, mainly existed as dimeric hydrolyzed Cr(III) bound to natural organic matter. Dissolution kinetics of this species were fast (<= 1 day) at low pH (<3) and slightly slower (<= 5 days) at neutral pH. Furthermore, it proved possible to describe the solubility of the dimeric Cr(III) organic matter complex with a geochemical equilibrium model using only generic binding parameters, opening the way for use of geochemical models in risk assessments of Cr(III)-contaminated sites. (C) 2017 The Authors. Published by Elsevier Ltd.
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| 6. |
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| 7. |
- Ekström, Sara M., et al.
(författare)
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Reactivity of dissolved organic matter in response to acid deposition
- 2016
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Ingår i: Aquatic Sciences. - : Springer. - 1015-1621 .- 1420-9055. ; 78:3, s. 463-475
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Tidskriftsartikel (refereegranskat)abstract
- Fluvial export of organic matter from the terrestrial catchment to the aquatic system is a large and increasing carbon flux. The successful reduction in sulfuric acid deposition since the 1980s has been shown to enhance the mobility of organic matter in the soil, with more terrestrially derived dissolved organic matter (DOM) reaching aquatic systems. Changes in soil acidity also affect the quality of the DOM. In this study we explore the consequences this may have on the reactivity and turnover of the terrestrially derived DOM as it reaches the aquatic system. DOM of different quality (estimated by absorbance, fluorescence and size exclusion chromatography) was produced through extraction of boreal forest O-horizon soils from podzol at two sulfuric acid concentrations corresponding to natural throughfall in spruce forest in Southern Sweden around 1980 and today. Extraction was done using two different methods, i.e. field leaching and laboratory extraction. The DOM extracts were used to assess if differences in acidity generate DOM of different reactivity. Three reactivity experiments were performed: photodegradation by UV exposure, biodegradation by bacteria, and biodegradation after UV exposure. Reactivity was assessed by measuring loss of dissolved organic carbon and absorbance, change in fluorescence and molecular weight, and bacterial production. DOM extracted at lower sulfuric acid concentration was more susceptible to photooxidation, and less susceptible to bacterial degradation, than DOM extracted at a higher sulfuric acid concentration. Thus the relative importance of these two turnover processes may be altered with changes in acid deposition.
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| 8. |
- Enell, Anja, et al.
(författare)
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Combining Leaching and Passive Sampling To Measure the Mobility and Distribution between Porewater, DOC, and Colloids of Native Oxy-PAHs, N-PACs, and PAHs in Historically Contaminated Soil
- 2016
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 50:21, s. 11797-11805
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Tidskriftsartikel (refereegranskat)abstract
- Different methods to quantify soil porewater concentrations of contaminants will provide different types of information. Passive sampling measurements give freely dissolved porewater concentrations (C-pw,C-free), while leaching tests provide information on the mobile concentration (C-pw,C-leach), including contaminants associated with dissolved organic carbon (DOC) and particles/colloids in the porewater. This study presents a novel combination of these two measurements, to study the sorption and mobility of polycyclic aromatic compounds (PACs) to DOC and particulate organic carbon (POC) in 10 historically contaminated soils. The PACs investigated were polycyclic aromatic hydrocarbons (PAHs), oxygenated-PAHs, and nitrogen containing heterocyclic PACs. Observed C-pw,C-leach was up to 5 orders of magnitude higher than C-pw,C-free; implying large biases when C-pw,C-leach is used to assess bioavailability or soil partitioning. Sorption of PACs to DOC and POC was important for the mobility of compounds with log K-OW > 4. Average DOC/water-partitioning coefficients (K-DOC) correlated well with KOW (log K-DOC = 0.89 x log K-OW +1.03 (r(2) = 0.89)). This relationship is likely more accurate for historically contaminated soils than previously published data, which suffer from artifacts caused by problems in measuring C-pw,C-free correctly or not using historically contaminated soils. POC/water-partitioning coefficients (K-POC) were orders of magnitude larger than corresponding K-DOC, suggesting sorption to mobile particles/colloids is the dominant mechanism for PAC mobility.
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| 9. |
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| 10. |
- Gustavsson, Jakob, et al.
(författare)
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Influence of natural organic matter on the extraction efficiency of flame retardants from surface waters
- 2017
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Ingår i: Journal of Chromatography A. - : Elsevier BV. - 0021-9673 .- 1873-3778. ; 1524, s. 74-86
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Tidskriftsartikel (refereegranskat)abstract
- The influence of natural organic matter (NOM) on the solid-phase extraction (SPE) efficiency was investigated for legacy and emerging flame retardants (FRs; n =26) in surface water. Three different groups of FRs were analyzed: polybrominated diphenyl ethers (PBDEs), halogenated flame retardants (HFRs), and organophosphorus flame retardants (OPFRs). In addition, five sorbents (Amberlite XAD-2, Amberlite IRA-743, Oasis HLB, Chromabond HR-P, and Chromabond HR-X) were evaluated for the extraction of FRs (n=33) in water, of which Oasis HLB eluted with dichloromethane and acetone:n-hexane (1:1, v/v) provided the highest overall recoveries. In subsequent NOM experiments, where FRs were extracted from water containing different NOM concentrations, both increased and decreased extraction efficiency with increasing NOM level were observed. Physicochemical and semi-empirical quantum chemistry properties were calculated for the FRs and used for analyzing relations between FRs. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) showed that the FRs separated into four different groups based on their properties. The FRs within each group responded similarly to increasing NOM, while differences in behavior were observed between the groups. This suggests that the structural properties of micropollutants highly influence NOM-FR interaction mechanisms. For instance, at high NOM levels, recoveries decreased substantially for FRs containing a moiety that can form strong hydrogen bonds (such as the double-bonded oxygen in e.g., OPFRs). Many of the compounds showed maximum extraction efficiency at higher levels of NOM. This suggests that binding of NOM to the sorbent and subsequent interaction between sorbent-bound NOM and FRs is an important mechanism for extraction of micropollutants from surface waters. (C) 2017 Elsevier B.V. All rights reserved.
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