| 1. |
- Abel, Sebastian, 1988-, et al.
(författare)
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Chemical Activity-Based Loading of Artificial Sediments with Organic Pollutants for Bioassays : A Proof of Concept
- 2024
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Ingår i: Environmental Toxicology and Chemistry. - 0730-7268 .- 1552-8618. ; 43:2, s. 279-287
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Tidskriftsartikel (refereegranskat)abstract
- Persistent organic pollutants (POPs) pose a risk in aquatic environments. In sediment, this risk is frequently evaluated using total or organic carbon-normalized concentrations. However, complex physicochemical sediment characteristics affect POP bioavailability in sediment, making its prediction a challenging task. This task can be addressed using chemical activity, which describes a compound's environmentally effective concentration and can generally be approximated by the degree of saturation for each POP in its matrix. We present a proof of concept to load artificial sediments with POPs to reach a target chemical activity. This approach is envisioned to make laboratory ecotoxicological bioassays more reproducible and reduce the impact of sediment characteristics on the risk assessment. The approach uses a constantly replenished, saturated, aqueous POP solution to equilibrate the organic carbon fraction (e.g., peat) of an artificial sediment, which can be further adjusted to target chemical activities by mixing with clean peat. We demonstrate the applicability of this approach using four polycyclic aromatic hydrocarbons (acenaphthene, fluorene, phenanthrene, and fluoranthene). Within 5 to 17 weeks, the peat slurry reached a chemical equilibrium with the saturated loading solution. We used two different peat batches (subsamples from the same source) to evaluate the approach. Variations in loading kinetics and eventual equilibrium concentrations were evident between the batches, which highlights the impact of even minor disparities in organic carbon properties within two samples of peat originating from the same source. This finding underlines the importance of moving away from sediment risk assessments based on total concentrations. The value of the chemical activity-based loading approach lies in its ability to anticipate similar environmental impacts, even with varying contaminant concentrations.
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| 2. |
- Borgenvik, Anna, 1987-, et al.
(författare)
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Dormant SOX9-Positive Cells Facilitate MYC-Driven Recurrence of Medulloblastoma
- 2022
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Ingår i: Cancer Research. - : AMER ASSOC CANCER RESEARCH. - 0008-5472 .- 1538-7445. ; 82:24, s. 4586-4603
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Tidskriftsartikel (refereegranskat)abstract
- Relapse is the leading cause of death in patients with medulloblas-toma, the most common malignant pediatric brain tumor. A better understanding of the mechanisms underlying recurrence could lead to more effective therapies for targeting tumor relapses. Here, we observed that SOX9, a transcription factor and stem cell/glial fate marker, is limited to rare, quiescent cells in high-risk medulloblastoma with MYC amplification. In paired primary-recurrent patient samples, SOX9-positive cells accumulated in medulloblastoma relapses. SOX9 expression anti-correlated with MYC expression in murine and human medulloblastoma cells. However, SOX9-positive cells were plastic and could give rise to a MYC high state. To follow relapse at the single-cell level, an inducible dual Tet model of medulloblastoma was developed, in which MYC expression was redirected in vivo from treatment-sensitive bulk cells to dormant SOX9-positive cells using doxycycline treatment. SOX9 was essential for relapse initiation and depended on suppression of MYC activity to promote therapy resistance, epithelial-mesenchymal transition, and immune escape. p53 and DNA repair pathways were downregulated in recurrent tumors, whereas MGMT was upregulated. Recurrent tumor cells were found to be sensitive to treatment with an MGMT inhibitor and doxorubicin. These findings suggest that recurrence-specific targeting coupled with DNA repair inhibition comprises a potential therapeutic strategy in patients affected by medulloblastoma relapse.Significance: SOX9 facilitates therapy escape and recurrence in medulloblastoma via temporal inhibition of MYC/MYCN genes, revealing a strategy to specifically target SOX9-positive cells to prevent tumor relapse.
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| 3. |
- Eriksson Wiklund, Ann-Kristin, et al.
(författare)
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Cardiotoxic and neurobehavioral effects of sucralose and acesulfame in Daphnia : Toward understanding ecological impacts of artificial sweeteners
- 2023
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Ingår i: Comparative Biochemistry and Physiology - Part C. - 1532-0456 .- 1878-1659. ; 273
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Tidskriftsartikel (refereegranskat)abstract
- Artificial sweeteners are widely used in food and pharmaceuticals, but their stability and persistence raise concerns about their impact on aquatic life. Although standard toxicity tests do not reveal lethal effects, recent studies suggest a potential neurotoxic mode of action. Using environmentally relevant concentrations, we assessed the effects of sucralose and acesulfame, common sugar substitutes, on Daphnia magna focusing on biochemical (acetylcholinesterase activity; AChE), physiological (heart rate), and behavioural (swimming) endpoints. We found dose-dependent increases in AChE and inhibitory effects on heart rate and behaviour for both substances. Moreover, acesulfame induced a biphasic response in AChE activity, inhibiting it at lower concentrations and stimulating at higher ones. For all endpoints, the EC50 values were lower for acesulfame than for sucralose. Additionally, the relationship between acetylcholinesterase and heart rate differed depending on the substance, suggesting possible differences in the mode of action between sucralose and acesulfame. All observed EC50 values were at μg/l levels, i.e., within the levels reported for wastewater, with adverse effects observed at as low as 0.1 μg acesulfame /l. Our findings emphasise the need to re-evaluate risk assessment thresholds for artificial sweeteners and provide evidence for the neurotoxic effects of artificial sweeteners in the environment, informing international regulatory standards.
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| 4. |
- Granberg, Maria, et al.
(författare)
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Microlitter in arctic marine benthic food chains and potential effects on sediment dwelling fauna
- 2020
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Ingår i: TemaNord report. - : Nordic Council of Ministers. ; :528
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Tidskriftsartikel (refereegranskat)abstract
- Marine litter pollution affects oceans globally and has today also made its way to the pristine arctic environment adding to the microlitter from local pollution sources. Marine litter pollution is recognized as a serious threat to the marine environment at all levels, from the UN to regional (EU, OSPAR, HELCOM) and national authorities. The risk posed by microlitter to marine biota is related to their documented ubiquity and long residence time in marine ecosystems. Risks are also mediated by intrinsic toxicity of added chemicals and potential adsorbance of other pollutants. When released into the marine environment, a major part of microlitter likely accumulate in beach sand and marine sediments either immediately or after acquiring a biofilm. It is therefore expected that benthic food chains will be key to understanding fate and effects (i.e. concentrations, potential trophic transfer and biological impact) of microlitter in the marine environment. The overall aim of the project was to determine abundance of microlitter pollution in marine sediments and benthic food chains in the Arctic, and to evaluate the abundance in relation to potential local sources and background levels. The aim was also to investigate potential effects of microplastic pollution on benthic organisms through laboratory studies using an arctic amphipod as a model organism. The field investigations in Svalbard, Norway and Greenland focused on determining microlitter particle concentrations and characteristics in marine sediments and biota collected close to and far from potential local pollution sources and pathways, i.e. outlets of untreated wastewater and effluents from a dumping site in Sisimiut, West Greenland and outlets of treated (Ny-Ålesund) and untreated (Longyearbyen) wastewater in Svalbard. Overall, higher concentrations and a higher diversity of microlitter types and polymers were found in sediments and organisms (blue mussels and cod) closer to human settlements (wastewater outlets and dumping sites) and in places where lost and/or dumped fishing gear accumulate. Thus, we can confidently conclude that local pollution sources for anthropogenic microlitter do exist in the Arctic. The experimental studies investigated whether environmentally relevant and future predicted concentrations of microplastics could impact feeding rate, microplastic ingestion, respiration and locomotion activity in an arctic sediment dwelling amphipod. The experimental results confirm previous microplastics studies on marine invertebrates showing effect only at very high concentrations not yet relevant in the arctic environment. The shape of the plastic particles was found to affect the particle fate. While microplastic fragments were ingested, short microplastic fibres attached to the carapace of the amphipods and likely obstructed normal ventilation behaviour. Furthermore, biofilm cover was found to affect the behaviour and effects of the particles. Microlitter naturally become covered by biofilms in the environment and our results stress the importance of effect experiments being carried out using naturally fouled plastics for ecological relevance. This report provides both environmental- and impact data related to microlitter pollution in the arctic marine environment. Although the levels of microplastics required to cause effects in experimental organisms in this study were much higher than what was detected in the field, there may be other species that are more sensitive than the one tested in nature. The currently relatively low microlitter concentrations detected in the field should be considered as a “window of opportunity” to act to at least reduce local pollution. Consequently, introduction of sustainable waste management and wastewater treatment should be an important focus of local management initiatives.
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| 5. |
- Lagerström, Maria, 1986, et al.
(författare)
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Antifouling paints leach copper in excess – study of metal release rates and efficacy along a salinity gradient
- 2020
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Ingår i: Water Research. - : Elsevier BV. - 0043-1354 .- 1879-2448. ; 186
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Tidskriftsartikel (refereegranskat)abstract
- Antifouling paints are biocidal products applied to ship and boat hulls in order to prevent the growth and settlement of marine organisms, i.e. fouling. The release of biocides from the surface of the paint film act to repel or poison potential settling organisms. Currently, the most commonly used biocide in antifouling paints is cuprous oxide. In the EU, antifouling products are regulated under the Biocidal Products Regulation (BPR), which states that the recommended dose should be the minimum necessary to achieve the desired effect. For antifouling products, the dose is measured as the release rate of biocide(s) from coating. In this study, the release rates of copper and zinc from eight different coatings for leisure boats were determined through static exposure of coated panels in four different harbors located in Swedish waters along a salinity gradient ranging from 0 to 27 PSU. The results showed the release rate of copper to increase with increasing salinity. Paints with a higher content of cuprous oxide were also found to release larger amounts of copper. The coatings’ ability to prevent biofouling was also evaluated and no significant difference in efficacy between the eight tested products was observed at the brackish and marine sites. Hence, the products with high release rates of copper were equally efficient as those with 4 – 6 times lower releases. These findings suggest that current antifouling paints on the market are leaching copper in excess of the effective dose in brackish and marine waters. Additionally, the results from the freshwater site showed no benefit in applying a copper-containing paint for the purpose of fouling prevention. This indicates that the use of biocidal paints in freshwater bodies potentially results in an unnecessary release of copper. By reducing the release rates of copper from antifouling paints in marine waters and restricting the use of biocidal paints in freshwater, the load of copper to the environment could be substantially reduced.
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| 6. |
- Lagerström, Maria, et al.
(författare)
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Flawed risk assessment of antifouling paints leads to exceedance of guideline values in Baltic Sea marinas
- 2020
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Ingår i: Environmental Science and Pollution Research. - : Springer Science and Business Media LLC. - 0944-1344 .- 1614-7499. ; 27:22, s. 27674-27687
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Tidskriftsartikel (refereegranskat)abstract
- The seasonal variations of dissolved and bioavailable copper (Cu) and zinc (Zn) were studied in two recreational marinas in Sweden and Finland. The time series from the two marinas were characterized by rising concentrations during the spring boat launching, elevated concentrations all through the peak boating season, and decreasing concentrations in autumn when boats were retrieved for winter storage. This pattern shows a clear link between Cu and Zn concentrations and boating activity, with antifouling paints as the principal source. The leaching from antifouling paints was also found to significantly alter the speciation of dissolved Cu and Zn in marina waters, with an increase of the proportion of metals that may be considered bioavailable. This change in speciation, which occurred without any change in dissolved organic carbon (DOC), further increases the environmental risk posed by antifouling paints. In the Swedish marina, dissolved Cu and Zn exceed both Environmental Quality Standards (EQS) and Predicted No Effect Concentrations (PNEC), indicating that the current Swedish risk assessment (RA) of antifouling paints is failing to adequately protect the marine environment. An evaluation of the RA performance showed the underlying cause to be an underestimation of the predicted environmental concentration (PEC) by factors of 2 and 5 for Cu and Zn, respectively. For both metals, the use of inaccurate release rates for the PEC derivation was found to be either mainly (Cu) or partly (Zn) responsible for the underestimation. For Zn, the largest source of error seems to be the use of an inappropriate partitioning coefficient (K-D) in the model. To ensure that the use of antifouling coatings does not adversely impact the sensitive Baltic Sea, it is thus recommended that the K-D value for Zn is revised and that representative release rates are used in the RA procedure.
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| 7. |
- 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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| 8. |
- Ytreberg, Erik, 1980, et al.
(författare)
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Environmental risk assessment of using antifouling paints on pleasure crafts in European Union waters
- 2021
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Ingår i: Journal of Environmental Management. - : Elsevier BV. - 0301-4797 .- 1095-8630. ; 281
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Tidskriftsartikel (refereegranskat)abstract
- The Authors To ensure sustainable use of antifouling paints, the European Union have developed a new environmental risk assessment tool, which a product must pass prior to its placement on the market. In this new tool, environmental concentrations are predicted based on estimated release rates of biocides to the aquatic environment and risk characterization ratios are calculated in regional spreadsheets. There are currently two methods in use to predict release rates of biocides; a calculation method and a laboratory method. These methods have been believed to overestimate environmental release of biocides and therefore fixed correction factors to reduce the release rate can be applied. An alternative method, known as the XRF method, has recently been developed and used to derive field release rates from antifouling paints. The aim of this study was to review the new environmental risk assessment tool and assess how the choice of release rate method and application of correction factors impact the approval of antifouling paint products. Eight coatings were environmentally risk assessed for usage in four European marine regions; Baltic, Baltic Transition, Atlantic and Mediterranean; by applying release rates of copper and zinc determined with the different methods. The results showed none of the coatings to pass the environmental risk assessment in the Baltic, Baltic Transition and the Mediterranean if field release rates were used. In contrast, most of the coatings passed if the correction factors were applied on the release rates obtained with the calculation or laboratory method. The results demonstrate the importance of release rate method choice on the outcome of antifouling product approval in EU. To reduce the impact of antifouling paints on the marine environment it is recommended that no correction factors should be allowed in the environmental risk assessment or preferably that site-specific field release rates are used. If the regulation in the European Union (and elsewhere) continues to allow correction factors, the pressure of biocides to the environment from leisure boating will result in degradation of marine ecosystems.
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| 9. |
- Ytreberg, Erik, 1980, et al.
(författare)
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Förbättrad riskbedömning av båtbottenfärger
- 2020
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Ett obehandlat båtskrov riskerar att snabbt bli beväxt av tusentals olika växt- och djurarter. Detta så kallade påväxttryck varierar stort mellan olika vattenområden och är t.ex. lägre i Östersjön än vad det är i Kattegatt. Påväxten ökar friktionen mellan skrov och vatten vilket gör att båten går långsammare. För att bibehålla samma fart krävs en högre bränsleförbrukning vilket leder till ökade luftutsläpp. För att förhindra påväxt målas oftast fritidsbåtsskrov med giftig, biocidinnehållande båtbottenfärg, även kallade antifoulingfärg. Dessa färger är designade att läcka biocider till det omgivande vattnet och skapar därigenom en hög koncentration av biociden vid gränsskiktet mellan skrov och vatten vilket förhindrar att påväxtorganismer kan fästa till båtskrovet. Färger som innehåller och läcker biocider måste tillståndsprövas innan de får lanseras på marknaden inom Europeiska Unionen (EU). I denna tillståndsprövning måste färgtillverkaren genomföra en miljöriskbedömning av färgen för att visa att läckaget av biocider inte ger oacceptabla risker för miljön. Vid miljöriskbedömningen är läckagehastigheten av biocider från färg till vatten den viktigaste parametern, vilken styr om produkten kommer få ett godkännande för användning eller ej. I dagsläget används två olika standardiserade tekniker för att bestämma läckagehastigheter, en laborativ och en matematisk. Vid en jämförelse med andra fältmetoder har dock dessa metoder visat sig ha begränsad förmåga att prediktera läckagehastigheter. Med en ny metod, baserad på röntgenflourescens (XRF), kan läckagehastigheter från olika färger bestämmas på ett snabbt och enkelt sätt. Genom att måla paneler med färger innehållande olika koncentrationer av koppar och zink kan metoden först användas för att mäta mängd metaller som finns i det målade färgskiktet. Därefter kan panelen antingen sänkas ned i olika hamnar eller fästas på skrov och efter en viss tid i vatten åter analyseras med XRF. Genom att mäta med XRF-metoden före nedsänkandet och sedan efter en viss tid i vatten, får man information om hur mycket koppar och zink som läckt ut från färgen till havsmiljön.
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