| 1. |
- Dahlberg, Anna-Karin, et al.
(författare)
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Capping fiberbank sediments to reduce persistent organic pollutants (POPs) fluxes : A large-scale laboratory column experiment
- 2023
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Ingår i: Environmental Pollution. - : Elsevier BV. - 0269-7491 .- 1873-6424. ; 333
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Tidskriftsartikel (refereegranskat)abstract
- Deposits of contaminated wood fiber waste (fiberbanks), originating from sawmills and pulp and paper industries, have been found in the aquatic environment in boreal countries. In-situ isolation capping has been proposed as a remediation solution because it has the potential to prevent dispersal of persistent organic pollutants (POPs) from this type of sediment. However, knowledge about the performance of such caps when placed on very soft (un-consolidated), gaseous organic rich sediment is scarce. We investigated the effectiveness of conventional in-situ capping to limit POPs fluxes to the water column from contaminated fibrous sediments that produce gas. A controlled, large-scale laboratory column (40 cm diameter, 2 m height) experiment was performed over 8 months to study changes in sediment-to-water fluxes of POPs and particle resuspension before and after capping the sediment with crushed stones (& GE;4 mm grain size). Two different cap thicknesses were tested (20 and 45 cm) on two types of fiberbank sediment with different fiber type composition. Results showed that capping fiberbank sediment with a 45 cm gravel cap reduced the sediment-to-water flux by 91-95% for p,p'-DDD, o,p'-DDD, by 39-82% for CB-101, CB-118, CB-138, CB-153, CB-180 and by 12-18% for HCB, whereas for less hydrophobic PCBs, capping was largely ineffective (i.e. CB-28 and CB-52). Although cap application caused particle resus-pension, the long-term effect of the cap was reduced particle resuspension. On the other hand, substantial sediment consolidation released large volumes of contaminated pore water into the overlying water body. Importantly, both sediment types produced large amount of gas, observed as gas voids forming inside the sediment and gas ebullition events, which increased pore water advection and affected the structural integrity of the cap. This may limit the practical applicability of this method on fiberbank sediments.
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| 2. |
- Dahlberg, Anna-Karin, et al.
(författare)
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Dispersal of persistent organic pollutants from fiber-contaminated sediments : biotic and abiotic pathways
- 2021
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Ingår i: Journal of Soils and Sediments. - : Springer Science and Business Media LLC. - 1439-0108 .- 1614-7480. ; 21:4, s. 1852-1865
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Tidskriftsartikel (refereegranskat)abstract
- PurposeNumerous sites contaminated with fiber emissions from pulp and paper industries are found in coastal areas of the Baltic Sea, but there is limited knowledge about the magnitude of dispersal of persistent organic pollutants (POPs) from these anthropogenic, organic-rich sediments called fiberbanks. The aim of this study was to quantify and compare different POP dispersal pathways from such fiberbanks. Dispersal mechanisms studied included abiotic and biotic routes (dissolved in water, particle-bound, and bioaccumulation).Materials and methodsContaminated fibrous sediments located in Ångermanälven River estuary in north-eastern Sweden were studied in sediment types representing different fiber content (i.e., fiberbanks, fiber-rich sediments, and less fiber impacted sediments). Sediment-to-water fluxes of dissolved contaminants (polychlorinated biphenyls (PCBs), hexachlorobenzene (HCB), and dichlorodiphenyltrichloroethane (DDT)) were measured in situ using benthic flux chambers. Particle resuspension was measured by sampling bottom water, before and after disturbing the sediment surface. Benthic biota was collected to determine the body burden of contaminants and to determine biota-pore water accumulation factors (BAFPW) and biota-sediment accumulation factors (BSAFs). In addition, concentrations of dissolved POPs in the water column were measured in field using passive samplers. Instrumental analysis was performed using gas chromatography coupled to a triple quadrupole mass spectrometer (GC-MS/MS).Results and discussionThe flux of dissolved Σ20PCBs was approximately two times higher from one of the investigated fiberbanks (3.4 ng m− 2 day− 1) compared to the other. The average particle burden of PCBs was also higher at this fiberbank after artificial disturbance (15 ng g−1 particle), which indicates that larger amounts of contaminants are likely to disperse via particle resuspension from this site compared to the other fiberbank (4.8 ng g− 1 particle). The difference might be associated with a layer of recently settled minerogenic material that covers one of the fiberbanks, which probably functions as a protective barrier. The lack of benthic biota implies that contaminant release by bioturbation is negligible in the studied fiberbanks. However, benthic biota from fiber-rich sediment showed bioaccumulation and biomagnification of contaminants.ConclusionsThe importance of diffusive flux from fiberbanks under undisturbed conditions became apparent when the different dispersal pathways were quantified. However, no dispersal pathway could be judged as irrelevant, since even under undisturbed conditions, advective particle transport was significant. Additionally, the uptake by biota and trophic transfer can be considerable. Quantification of dispersal routes and understanding of the relative importance of various pathways is critical for proper risk assessment and management of contaminated sediments.
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| 3. |
- Goransson, Gunnel, et al.
(författare)
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Assessing the Risk of Contaminant Dispersion From Fibrous Sediments of Industrial Origin
- 2021
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Ingår i: Frontiers in Marine Science. - : Frontiers Media S.A.. - 2296-7745. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Unregulated discharges of wastewater from pulp and paper factories resulted in the formation of relatively thick organic (cellulose) rich sediments in shallow waters along the Swedish coast. These deposits are known as fiberbanks and are contaminated by persistent organic pollutants (POPs), metals and methylmercury, which can be dispersed by diffusion and advective processes coupled to propeller wash, high river discharges, strong wind waves and submarine landslides. Based on a case study of polychlorinated biphenyls (PCBs), one group of prevalent POPs in the fiberbanks, we present a probabilistic approach to estimate the potential risk of dispersion of fiberbank contaminants. The approach allows for estimation of the dispersal pathways that dominates the risk within a given time and provides more insight about the significance of various dispersion processes. We show that it is highly likely that chemical diffusion and advection triggered by ship-induced resuspension will disperse PCBs (sum of seven congeners; sigma 7PCB) above a threshold level for environmental impact, while the likelihood of river and wind-wave generated resuspension dispersion pathways are lower (similar to 20%, respectively). We further show that there is approximately 5% likelihood that a submarine landslide will disperse sigma 7PCB above the threshold level. The study implies that the governing parameters for risk assessment specifically should include reliable data on contaminant concentration, water depth above the fiberbank, estimation of concerned fiberbank areas, time duration of erosive fluid flows and measured diffusion. The approach provides insight into the importance of various dispersion processes. We suggest that it can be applied to support risk assessment, especially when there are limited available data and/or knowledge about the system under study.
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| 4. |
- Lehoux, Alizée, et al.
(författare)
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Extreme gas production in anthropogenic fibrous sediments : An overlooked biogenic source of greenhouse gas emissions
- 2021
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Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 781
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Tidskriftsartikel (refereegranskat)abstract
- Fibrous sediments that originated from old pulp and paper industry emissions are recognized as a potential threat to the aquatic environment because they are highly contaminated. In addition, biogenic degradation of the organic material from so-called "fiberbanks" has a high potential to produce greenhouse gases (GHG). In this study, X-ray tomography, optical sensors and gas analyzers were used to identify and quantify the gas produced and released from samples of two different fiberbanks. We show that a finer fibrous structure allows the formation of larger gas bubbles and higher gas production rates compared to coarser material composed of wood pieces. High contents of methane (average 56% to 65%) and carbon dioxide (average 18% to 20%) were measured in the gas emitted from both types of fiberbank. Measured methane production rates from the fiberbanks samples are one to three orders of magnitude higher than previously reported rates from sediments within the studied temperature range (between 0.03 and 0.51 mu m CH4/h/g dw over 4.7 to 20 degrees C). The potential for methane and carbon dioxide production in the fiberbank volume likely present in Sweden is estimated to correspond to 7% of Sweden's total known GHG emissions for 2019. These findings show that fiberbanks have the potential to be a significant emitter of GHG.
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| 5. |
- Wiberg, Karin, et al.
(författare)
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Spatial distribution of legacy pesticides in river sediment from the Republic of Moldova
- 2021
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 279
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Tidskriftsartikel (refereegranskat)abstract
- Historical use of organochlorine pesticides (OCPs) in the Republic of Moldova could pose a potential risk for the aquatic environment due to the persistence, bioaccumulation and toxic properties of these environmental pollutants. However, knowledge on environmental concentrations of legacy OCPs in Moldova is limited. In this study, surface sediment from the two main rivers; Dniester (8 sites, n = 15) and Prut (6 sites, n = 12), and two tributary rivers; Bic (11 sites, n = 11) and Raut (6 sites, n = 6), were collected during 2017-2018 and analyzed for hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethanes (DDTs) and their transformation products (DDDs and DDEs) using gas chromatography coupled to mass spectrometry (GC-MS/MS). Sediment concentrations of Sigma 6DDX (1.9-140 ng g(-1) dry weight (dw)) and Sigma(4)HCHs (n.d-2.5 ng g(-1) dw) were found. In the big rivers, the average Sigma 6DDX concentration (18 ng g(-1) dw) were 35 times higher than Sigma(4)HCHs (0.51 ng g(-1) dw). Whereas, in the small rivers the average Sigma 6DDX concentration (32 ng g(-1) dw) was approximately 41 times higher than Sigma(4)HCHs (0.77 ng g(-1) dw). Compared to previous studies from Eastern Europe, the sediment levels were generally similar as found in Moldova's neighboring countries (Romania and Ukraine). Overall, the contamination profile indicates long-term ageing of OCPs used in the past in the agricultural sector. Less than half of the sites (45%) had levels that pose a potential risk for benthic organisms. Hence, further work is needed to determine the bioaccumulation of OCPs in the aquatic food web in this region and the associated risks to ecosystems and human health.
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| 6. |
- Dahlberg, Anna-Karin, 1982-, et al.
(författare)
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Persistent organic pollutants in wood fiber–contaminated sediments from the Baltic Sea
- 2020
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Ingår i: Journal of Soils and Sediments. - : Springer Science and Business Media LLC. - 1439-0108 .- 1614-7480. ; 20:5, s. 2471-2483
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Tidskriftsartikel (refereegranskat)abstract
- Many coastal areas in the Baltic Sea are contaminated with wood fiber and pollutants from pulp and paper industries. These anthropogenic, organic-rich, sediments (fiberbanks) have not been characterized and knowledge about their role as secondary sources for dispersal of persistent organic pollutants (POPs) is limited. Hence, the aim of this study was to elucidate the fate of POPs and the relationships between sorption (KD and KTOC), sediment type, and compound hydrophobicity (KOW) in fiber-contaminated sediments.
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| 7. |
- Dahlberg, Helena, 1980, et al.
(författare)
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Open and Reflective Lifeworld Research: A Third Way
- 2020
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Ingår i: Qualitative Inquiry. - : SAGE Publications. - 1077-8004 .- 1552-7565. ; 26:5, s. 458-464
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Tidskriftsartikel (refereegranskat)abstract
- With the mission in mind to articulate an approach that is scientifically competent to meet the appeals from health care, education, social work, and other disciplines, the theme of this article is to rethink the essential ideas of phenomenological and hermeneutical research approaches, by exploring their philosophical underpinnings and especially the essential ontological idea of inseparability. We examine the fissure between approaches that favor description or interpretation and explore the arguments for a third approach that has the power to close the false epistemological methodological gap.
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| 8. |
- Volchko, Yevheniya, 1979, et al.
(författare)
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Assessing costs and benefits of improved soil quality management in remediation projects : A study of an urban site contaminated with PAH and metals
- 2020
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Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 707
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Tidskriftsartikel (refereegranskat)abstract
- Contaminants in the soil may threaten soil functions (SFs) and, in turn, hinder the delivery of ecosystem services (ES). A framework for ecological risk assessments (ERAs) within the APPLICERA - APPLICable site-specific Environmental Risk Assessment research project promotes assessments that consider other soil quality parameters than only contaminant concentrations. The developed framework is: (i) able to differentiate the effects of contamination on SFs from the effects of other soil qualities essential for soil biota; and (ii) provides a robust basis for improved soil quality management in remediation projects. This study evaluates the socio-economic consequences of remediation alternatives stemming from a Tier 1 ERA that focusses on total contaminant concentrations and soil quality standards and a detailed, site-specific Tier 3 Triad approach that is based on the APPLICERA framework. The present study demonstrates how Tier 1 and Tier 3 ERAs differ in terms of the socio-economic consequences of their remediation actions, as well as presents a novel method for the semi-quantitative assessment of on-site ES. Although the presented Tier 3 ERA is more expensive and time-consuming than the more traditional Tier 1 ERA approach, it has the potential to lower the costs of remediation actions, decrease greenhouse gas emissions, reduce other environmental impacts, and minimise socio-economic losses. Furthermore, the remediation actions stemming from the Tier 3 ERA were predicted to exert far less negative ES effects than the actions proposed based on the results of the Tier 1 ERA.
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| 9. |
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| 10. |
- Dahlberg, Helena, 1980, et al.
(författare)
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Den fenomenologiska forskningens evidensanspråk
- 2019
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Ingår i: Fenomenologi i praktiken. fenomenologisk forskning i ett skandinaviskt perspektiv / Helena Dahlberg, Sidsel Ellingsen, Bente Martinsen, Susanne Rosberg (red.). - Stockholm : Liber. - 9789147113453 ; , s. 155-189
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Bokkapitel (refereegranskat)
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