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- 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. |
- Adolfsson-Erici, Margaretha, et al.
(författare)
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Undersökning av det syntetiska sötningsmedlet sukralos med avseende på eventuella ekotoxikologiska effekter
- 2001
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Två släkten av kräftdjur: Nitocra spinipes och Gammarus oceanicus resp zaddachiexponerades för sukralos i ekotoxikologiskt relevanta koncentrationer i kroniska tester. Viarbetade utifrån följande hypoteser: skalömsning hos kräftdjur störs av höga halter sukralos iomgivande vatten samt att sukralos inte biokoncentreras i exponerade organismer.Långtidsexponering resulterade i högre dödlighet hos juvenila gammarider. Sukralos syntesinte påverka skalömsningstiden för de adulta honorna i ett pre-copula experiment. Inga teckenpå biokoncentrering kunde märkas. Exponeringen av Nitocra resulterade i att de djur somexponerats för de lägre koncentrationerna av sukralos var längre jämfört med kontrolldjurenmedan för individer exponerade för de högre koncentrationerna minskade längden medökande sukraloskoncentration. De kortaste individerna återfanns i den positiva kontrollen ochhade exponerats för 50 μg/L lindan. RNA-innehållet varierade mellan exponeringarna och denvar lägst i 500μg/L och högst i 5000 μg/L exponeringen Vi fann däremot inget signifikantsamband mellan RNA-innehåll och tillväxthastighet hos Nitocra. Detta kan möjligen vara eneffekt av sukralosexponering, eftersom linjära responser från tidigare experiment har noterats.Inga skillnader avseende medelutvecklingstiden var signifikanta. Renat avloppsvatten frånHenriksalsverken innehöll relativt höga koncentrationer sukralos liksom ytvatten från trereningsverksrecipienter.
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| 3. |
- Bejgarn, Sofia, et al.
(författare)
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Toxicity of leachate from weathering plastics : An exploratory screening study with Nitocra spinipes
- 2015
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 132, s. 114-119
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Tidskriftsartikel (refereegranskat)abstract
- Between 60% and 80% of all marine litter is plastic. Leachate from plastics has previously been shown to cause acute toxicity in the freshwater species Daphnia magna. Here, we present an initial screening of the marine environmental hazard properties of leachates from weathering plastics to the marine harpacticoid copepod [Crustacea] Nitocra spinipes. Twenty-one plastic products made of different polymeric materials were leached and irradiated with artificial sunlight. Eight of the twenty-one plastics (38%) produced leachates that caused acute toxicity. Differences in toxicity were seen for different plastic products, and depending on the duration of irradiation. There was no consistent trend in how toxicity of leachate from plastics changed as a function of irradiation time. Leachate from four plastics became significantly more toxic after irradiation, two became significantly less toxic and two did not change significantly. Analysis of leachates from polyvinyl chloride (PVC) by liquid chromatography coupled to a full-scan high-resolution mass spectrometer showed that the leachates were a mixture of substances, but did not show evidence of degradation of the polymer backbone. This screening study demonstrates that leachates from different plastics differ in toxicity to N. spinipes and that the toxicity varies under simulated weathering.
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| 8. |
- Breitholtz, Magnus, et al.
(författare)
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An evaluation of free water surface wetlands as tertiary sewage water treatment of micro-pollutants
- 2012
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Ingår i: Ecotoxicology and Environmental Safety. - : Elsevier BV. - 0147-6513 .- 1090-2414. ; 78, s. 63-71
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 9. |
- Breitholtz, Magnus, et al.
(författare)
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Are individual NOEC levels safe for mixtures? A study on mixture toxicity of brominated flame-retardants in the copepod Nitocra spinipes
- 2008
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 72:9, s. 1242-1249
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Tidskriftsartikel (refereegranskat)abstract
- In aquatic ecosystems organisms are exposed to mixtures of pollutants. Still, risk assessment focuses almost exclusively on effect characterization of individual substances. The main objective of the current study was therefore to study mixture toxicity of a common group of industrial substances, i.e., brominated flame–retardants (BFRs), in the harpacticoid copepod Nitocra spinipes. Initially, 10 BFRs with high hydrophobicity but otherwise varying chemical characteristics were selected based on multivariate chemical characterization and tested individually for effects on mortality and development using a partial life cycle test (six days) where silica gel is used as a carrier of the hydrophobic substances. Based on these findings, six of the 10 BFRs were mixed in a series of NOEC proportions (which were set to 0.008, 0.04, 0.2, 1, and five times the NOEC concentrations for each individual BFR), loaded on silica gel and tested in a full life cycle test (26 days). Significantly increased mortality was observed in N. spinipes after six and 26 days exposure at a NOEC proportion that equals the NOECLDR value (×1) for each BFR in the mixture (p = 0.0015 and p = 0.0105, respectively). At the NOEC × 5 proportion all animals were dead. None of the other NOEC proportions caused significant negative responses related to development and reproduction. This shows that low concentrations of individual substances can cause toxicity if exposed in mixtures, which highlights the need to consider mixture toxicity to a greater extent in regulatory work.
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| 10. |
- Breitholtz, Magnus, et al.
(författare)
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Calmodulin inhibition as a mode of action of antifungal imidazole pharmaceuticals in non-target organisms
- 2020
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Ingår i: Toxicology Research. - : Oxford University Press (OUP). - 2045-452X .- 2045-4538. ; 9:4, s. 425-430
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Tidskriftsartikel (refereegranskat)abstract
- To improve assessment of risks associated with pharmaceutical contamination of the environment, it is crucial to understand effects and mode of action of drugs in non-target species. The evidence is accumulating that species with well-conserved drug targets are prone to be at risk when exposed to pharmaceuticals. An interesting group of pharmaceuticals released into the environment is imidazoles, antifungal agents with inhibition of ergosterol synthesis as a primary mode of action in fungi. However, imidazoles have also been identified as competitive antagonists of calmodulin (CaM), a calcium-binding protein with phylogenetically conserved structure and function. Therefore, imidazoles would act as CaM inhibitors in various organisms, including those with limited capacity to synthesize sterols, such as arthropods. We hypothesized that effects observed in crustaceans exposed to imidazoles are related to the CaM inhibition and CaM-dependent nitric oxide (NO) synthesis. To test this hypothesis, we measured (i) CaM levels and its gene expression, (ii) NO accumulation and (iii) gene expression of NO synthase (NOS1 and NOS2), in the cladoceran Daphnia magna exposed to miconazole, a model imidazole drug. Whereas significantly increased CaM gene expression and its cellular allocation were observed, supporting the hypothesized mode of action, no changes occurred in either NO synthase expression or NO levels in the exposed animals. These findings suggest that CaM inhibition by miconazole leads to protein overexpression that compensates for the loss in the protein activity, with no measurable downstream effects on NO pathways. The inhibition of CaM in D. magna may have implications for effect assessment of exposure to mixtures of imidazoles in aquatic non-target species.
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