| 1. |
- Schönlau, Christine, 1986-
(författare)
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Microplastics in the marine environment and the assessment of potential adverse effects of associated chemicals
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- During the last decade plastics have gained interest by scientists as emerging pollutants particularly in the marine environment due to their ubiquity and persistence. While several studies report the occurrence of microplastics in surface waters globally, there are no harmonized methods to sample and measure microplastics, and the knowledge of toxicological effects in the marine ecosystem is scarce. One of the concerns is that microplastics could transfer hazardous chemicals into organism upon ingestion.In this thesis chemical and bioanalytical methods were combined to address the hypothesis that plastic pollution poses a risk for marine ecosystems by exposure to plastic associated chemicals such as sorbed environmental pollutants, additives, and monomers. Six different pristine plastic polymers were studied which have been deployed in the marine and freshwater system for up to 12 months. Potential adverse effects of plastic associated chemicals were investigated with in vitro reporter gene assays which can be activated by several chemical classes. The main focus was on the aryl hydrocarbon receptor-mediated activity for the assessment of dioxin-like chemicals. Different groups of persistent environmental pollutants, which are present in the aquatic environment, were analyzed by gas chromatographic mass spectrometric methods. The contribution of the targeted chemicals to the measured biological activities was examined by conducting potency balance calculations. A better knowledge about the occurrence of microplastics in the waters surrounding Sweden was gained by sampling surface waters comparing two different sampling techniques, trawl and in-situ pump.The plastic pellets induced bioactivities in most tested reporter gene assays and the activities varied by type of polymer. In the majority of samples the contribution of the targeted environmental pollutants to the observed bioactivities was low. Concentrations of microplastics > 0.3 mm in surface waters around Sweden were observed to be low and the findings of this thesis suggest that the tested polymers with sizes 2-4 mm will not lead to an increased risk for marine ecosystems in terms of exposure to chemicals.
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| 2. |
- Beiras, R., et al.
(författare)
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Ingestion and contact with polyethylene microplastics does not cause acute toxicity on marine zooplankton
- 2018
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Ingår i: Journal of Hazardous Materials. - : Elsevier. - 0304-3894 .- 1873-3336. ; 360, s. 452-460
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Tidskriftsartikel (refereegranskat)abstract
- Toxicity of polyethylene microplastics (PE-MP) of size ranges similar to their natural food to zooplanktonic organisms representative of the main taxa present in marine plankton, including rotifers, copepods, bivalves, echinoderms and fish, was evaluated. Early life stages (ELS) were prioritized as testing models in order to maximize sensitivity. Treatments included particles spiked with benzophenone-3 (BP-3), a hydrophobic organic chemical used in cosmetics with direct input in coastal areas. Despite documented ingestion of both virgin and BP-3 spiked microplastics no acute toxicity was found at loads orders of magnitude above environmentally relevant concentrations on any of the invertebrate models. In fish tests some effects, including premature or reduced hatching, were observed after 12 d exposure at 10 mg L-1 of BP-3 spiked PE-MP. The results obtained do not support environmentally relevant risk of microplastics on marine zooplankton. Similar approaches testing more hydrophobic chemicals with higher acute toxicity are needed before these conclusions could be extended to other organic pollutants common in marine ecosystems. Therefore, the replacement of these polymers in consumer products must be carefully considered.
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| 3. |
- Geng, Dawei, 1986-, et al.
(författare)
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Effect of perfluorooctanesulfonic acid (PFOS) on the liver lipid metabolism of the developing chicken embryo
- 2019
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Ingår i: Ecotoxicology and Environmental Safety. - : Elsevier. - 0147-6513 .- 1090-2414. ; 170, s. 691-698
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Tidskriftsartikel (refereegranskat)abstract
- Perfluorooctanesulfonate (PFOS) is a well-known contaminant in the environment and it has shown to disrupt multiple biological pathways, particularly those related with lipid metabolism. In this study, we have studied the impact of in ovo exposure to PFOS on lipid metabolism in livers in developing chicken embryos using lipidomics for detailed characterization of the liver lipidome. We used an avian model (Gallus gallus domesticus) for in ovo treatment at two levels of PFOS. The lipid profile of the liver of the embryo was investigated by ultra-high performance liquid chromatography combined with quadrupole-time-of-flight mass spectrometry and by gas chromatography mass spectrometry. Over 170 lipids were identified, covering phospholipids, ceramides, di- and triacylglycerols, cholesterol esters and fatty acid composition of the lipids. The PFOS exposure caused dose dependent changes in the lipid levels, which included upregulation of specific phospholipids associated with the phosphatidylethanolamine N-methyltransferase (PEMT) pathway, triacylglycerols with low carbon number and double bond count as well as of lipotoxic ceramides and diacylglycerols. Our data suggest that at lower levels of exposure, mitochondrial fatty acid β-oxidation is suppressed while the peroxisomal fatty acid β -oxidation is increased. At higher doses, however, both β -oxidation pathways are upregulated.
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| 4. |
- Hafner, Christoph, et al.
(författare)
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Investigations on sediment toxicity of German rivers applying a standardized bioassay battery
- 2015
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Ingår i: Environmental Science and Pollution Research. - : Springer Berlin/Heidelberg. - 0944-1344 .- 1614-7499. ; 22:21, s. 16358-16370
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Tidskriftsartikel (refereegranskat)abstract
- River sediments may contain a huge variety of environmental contaminants and play a key role in the ecological status of aquatic ecosystems. Contaminants adsorbed to sediments and suspended solids may contribute directly or after remobilization to an adverse ecological and chemical status of surface water. In this subproject of the joint research project DanTox, acetonic Soxhlet extracts from three German river sediments from the River Rhine (Altrip and Ehrenbreitstein with moderate contamination) and River Elbe (Veringkanal Hamburg heavily contaminated) were prepared and redissolved in dimethyl sulfoxide (DMSO). These extracts were analyzed with a standard bioassay battery with organisms from different trophic levels (bacteria, algae, Daphnia, fish) as well as in the Ames test and the umuC test for bacterial mutagenicity and genotoxicity according to the respective OECD and ISO guidelines. In total, 0.01 % (standard) up to 0.25 % (only fish embryo test) of the DMSO sediment extract was dosed to the test systems resulting in maximum sediment equivalent concentrations (SEQ) of 2 up to 50 g l(-1). The sediment of Veringkanal near Hamburg harbor was significantly more toxic in most tests compared to the sediment extracts from Altrip and Ehrenbreitstein from the River Rhine. The most toxic effect found for Veringkanal was in the algae test with an ErC50 (72 h) of 0.00226 g l(-1) SEQ. Ehrenbreitstein and Altrip samples were about factor 1,000 less toxic. In the Daphnia, Lemna, and acute fish toxicity tests, no toxicity at all was found at 2 g l(-1) SEQ. corresponding to 0.01 % DMSO. Only when increasing the DMSO concentration the fish embryo test showed a 22-fold higher toxicity for Veringkanal than for Ehrenbreitstein and Altrip samples, while the toxicity difference was less evident for the Daphnia test due to the overlaying solvent toxicity above 0.05 % dimethyl sulfoxide (DMSO). The higher toxicities observed with the Veringkanal sample are supported by the PAH and PCB concentrations analyzed in the sediments. The sediment extracts of Altrip andVeringkanal were mutagenic in the Ames tester strain TA98 with metabolic activation (S9mix). The findings allow a better ecotoxicological characterization of the sediments extensively analyzed in all subprojects of the DanTox project (e. g., Garcia-Kaeufer et al. Environ Sci Pollut Res. doi: 10.1007/s11356-014-3894-4, 2014; Schiwy et al. Environ Sci Pollut Res. doi: 10.1007/s11356-014-31850, 2014; Hollert and Keiter 2015). In the absence of agreed limit values for sediment extracts in standard tests, further data with unpolluted reference sediments are required for a quantitative risk assessment of the investigated polluted sediments.
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| 5. |
- Henriksson, Sara, 1975-, et al.
(författare)
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Uptake and bioaccumulation of PCDD/Fs in earthworms after in situ and in vitro exposure to soil from a contaminated sawmill site
- 2017
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Ingår i: Science of the Total Environment. - Amsterdam, Netherlands : Elsevier. - 0048-9697 .- 1879-1026. ; 580, s. 564-571
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Tidskriftsartikel (refereegranskat)abstract
- Uptake of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) was studied in earthworms collected from a sawmill site in Sweden with severe PCDD/Fs contamination (the hot spot concentration was 690,000 ng TEQWHO2005/kg d.w.) in order to investigate the transfer of PCDD/Fs from the site to the biota. PCDD/Fs concentrations in the collected earthworms were compared to PCDD/Fs concentrations in laboratory exposed earthworms (Eisenia fetida), which were exposed to contaminated soils from the sawmill site for 34 days. All analyses were performed by high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS). PCDD/Fs concentrations in the earthworms ranged from 290 to 520,000 pg/g (f.w.). The main congeners found in both soils and earthworms were OCDF, 1234678-HpCDF, OCDD and 1234678-HpCDD. The study showed that the PCDD/Fs in the soil were biovailable to the earthworms and the PCDD/Fs concentrations in the soils correlated with the concentrations in the earthworms. Earthworm samples from soil with lower concentration had higher bioaccumulation factors than samples from soils with high concentration of contamination. Thus, a less contaminated soil could yield higher concentrations in earthworms compared to a higher contaminated soil. Assuming that when assessing risks with PCDD/F contaminated soil, a combination of chemical analysis of soil PCDD/Fs concentrations and bioavailability should be employed for a more comprehensive risk assessment.
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| 6. |
- Jacobsen, Annette V., et al.
(författare)
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Effects of perfluorooctane sulfonate on genes controlling hepatic fatty acid metabolism in livers of chicken embryos
- 2018
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Ingår i: Environmental Science and Pollution Research. - : Springer Berlin/Heidelberg. - 0944-1344 .- 1614-7499. ; 25:23, s. 23074-23081
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Tidskriftsartikel (refereegranskat)abstract
- Per- and polyfluoroalkyl substances (PFAS) are synthetic surfactants with a wide variety of applications; however, due to their stability, they are particularly resistant to degradation and, as such, are classed as persistent organic pollutants. Perfluorooctane sulfonate (PFOS) is one such PFAS that is still detectable in a range of different environmental settings, despite its use now being regulated in numerous countries. Elevated levels of PFOS have been detected in various avian species, and the impact of this on avian health is of interest when determining acceptable levels of PFOS in the environment. Due to its similarities to naturally occurring fatty acids, PFOS has potential to disrupt a range of biological pathways, particularly those associated with lipid metabolism, and this has been shown in various species. In this study, we have investigated how in ovo exposure to environmentally relevant levels of PFOS affects expression of genes involved in lipid metabolism of developing chicken embryos. We have found a broad suppression of transcription of genes involved in fatty acid oxidation and PPAR-mediated transcription with more significant effects apparent at lower doses of PFOS. These results highlight the need for more research investigating the biological impacts of low levels of PFAS to properly inform environmental policy governing their regulation.
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| 7. |
- Keiter, Susanne, et al.
(författare)
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Does perfluorooctane sulfonate (PFOS) act as chemosensitizer in zebrafish embryos?
- 2016
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Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 548-549, s. 317-324
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Tidskriftsartikel (refereegranskat)abstract
- Earlier studies have shown that perfluorooctane sulfonate (PFOS) increases the toxicity of other chemicals by enhancing their uptake by cells and tissues. The present study aimed at testing whether the underlying mechanism of enhanced uptake of chemicals by zebrafish (Danio rerio) embryos in the presence of PFOS is by interference of this compound with the cellular efflux transporter Abcb4. Modifications of uptake/clearance and toxicity of two Abcb4 substrates, the fluorescent dye rhodamine B (RhB) and vinblastine, by PFOS were evaluated using 24 and 48. h post-fertilization (hpf) embryos. Upon 90. min exposure of 24. hpf embryos to 1. μM RhB and different PFOS concentrations (3-300. μM) accumulation of RhB in zebrafish was increased by up to 11.9-fold compared to controls, whereas RhB increases in verapamil treatments were 1.7-fold. Co-administration of PFOS and vinblastine in exposures from 0 to 48. hpf resulted in higher vinblastine-caused mortalities in zebrafish embryos indicating increased uptake of this compound. Interference of PFOS with zebrafish Abcb4 activity was further studied using recombinant protein obtained with the baculovirus expression system. PFOS lead to a concentration-dependent decrease of the verapamil-stimulated Abcb4 ATPase activity; at higher PFOS concentrations (250, 500. μM), also the basal ATPase activity was lowered indicating PFOS to be an Abcb4 inhibitor. In exposures of 48. hpf embryos to a very high RhB concentration (200. μM), accumulation of RhB in embryo tissue and adsorption to the chorion were increased in the presence of 50 or 100. μM PFOS. In conclusion, the results indicate that PFOS acts as inhibitor of zebrafish Abcb4; however, the exceptionally large PFOS-caused effect amplitude of RhB accumulation in the 1. μM RhB experiments and the clear PFOS effects in the experiments with 200. μM RhB suggest that an additional mechanism appears to be responsible for the potential of PFOS to enhance uptake of Abcb4 substrates.
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| 8. |
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| 9. |
- Lam, Monika M., 1987-
(författare)
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Characterization of PAC-contaminated soil with the focus on availability, leachability and biological activities
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Current risk assessments of polycyclic aromatic compounds (PACs)-contaminated soil are often based on the 16 priority PAHs and do not consider availability of PACs in soil sufficiently. This may lead to uncertainties of the assessment, since important contaminants can be overlooked and only a small fraction of contaminants is available for the uptake for organisms. The overall aim of this thesis was to develop a refined and enhanced analytical approach based on both chemical and bioassay analysis coupled to passive sampling with polyoxymethylene (POM) and leaching tests that can provide a more comprehensive picture of chemical pollution at PAC-contaminated sites. To achieve this, bioassay-specific relative potency factors (REPs) of PACs were determined for the H4IIE-luc bioassay, detecting AhR-mediated activity, and for the VM7luc4E2 transactivation assay, detecting ER-mediated activity for the use in potency-balance analysis. Results of uptake-experiments of PACs in earthworms and POM suggested that POM is a suitable tool to study availability of AhR and ER agonists in soil. Availability and mobility of PACs in soil were investigated by the use of POM and leaching tests. The results of potency-balance analysis showed that in soil samples, in POM-fractions or in leachates, a large fraction of AhR- or ER-agonists remained unexplained, despite the use of a large number of REPs. In addition, coupling of chemical and biological analysis to passive sampling or leaching tests revealed that only a small fraction of the total mass of PACs in the soil is available or leachable in soil. The results suggests that the use of only the total concentration in soil while ignoring unknown toxicants will lead to great uncertainties in the risk assessment. Therefore, effect-based screening using bioassays, taking availability and mobility of compounds into account, as well as a widened chemical analysis should be included in modern hazard- and risk assessment of PAH contaminated soils.
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| 10. |
- Lam, Monika M., 1987-, et al.
(författare)
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Methylated PACs Are More Potent than Their Parent Compounds : A Study on AhR-mediated Activity, Degradability and Mixture Interactions in the H4IIE-luc Assay
- 2018
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Ingår i: Environmental Toxicology and Chemistry. - : John Wiley & Sons. - 0730-7268 .- 1552-8618. ; 37:5, s. 1409-1419
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Tidskriftsartikel (refereegranskat)abstract
- Twenty-six polycyclic aromatic compounds (PACs; including native polycyclic aromatic hydrocarbons [PAHs], hydroxylated PAHs, alkylated and oxygenated PAHs, and [alkylated] heterocyclic compounds) were investigated for their aryl hydrocarbon receptor (AhR)-mediated potencies in the H4IIE-luc bioassay. Potential degradabilities of PACs were investigated by use of various durations of exposure (24, 48, or 72 h), and various mixtures of PACs including PAHs, alkylated and oxygenated PAHs, and heterocyclic compounds were tested for their joint AhR-mediated potency. Additive behaviors of PACs in mixtures were studied by comparing observed mixture potencies with mixture potencies predicted by use of the concentration addition model. Methylated derivatives were more potent than their parent compounds in the H4IIE-luc assay. A time-dependent decrease in relative potency was observed for all AhR-active compounds, which may be indicative of in vitro biotransformation. Monomethylated compounds seemed to be more rapidly transformed than analogous unsubstituted compounds. In addition, the results showed that the predictive power of the concentration addition model increased with the number of compounds, suggesting additivity in multicomponent mixtures. Due to the greater potency of methylated derivatives and their ubiquitous occurrence, there is a need for further research on the toxicity and mixture behavior of these environmentally and toxicologically relevant compounds.
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