| 1. |
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| 2. |
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| 3. |
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| 4. |
- Arnoldsson, Kristina, 1961-, et al.
(författare)
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Retention and maternal transfer of environmentally relevant polybrominated dibenzo-p-dioxins and dibenzofurans, polychlorinated dibenzo-p-dioxins and dibenzofurans, and polychlorinated biphenyls in zebrafish (Danio rerio) after dietary exposure
- 2012
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Ingår i: Environmental Toxicology and Chemistry. - : John Wiley & Sons. - 0730-7268 .- 1552-8618. ; 31:4, s. 804-812
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Tidskriftsartikel (refereegranskat)abstract
- High levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), mono- and non-ortho polychlorinated biphenyls (PCBs), and polybrominated dibenzo-p-dioxins (PBDDs) are found in fish from coastal areas in the Baltic Sea, which may cause ecotoxicological effects. To increase our understanding of the persistency of the emerging pollutants polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs), fish feed was spiked with 21 PBDD/Fs, 17 PCDD/Fs, and 30 PCBs and fed to zebrafish. Concentrations in fish and eggs were examined during a six- or twelve-week uptake period, and a six-week elimination period. Steady-state was reached for 2, 3, 7, and/or 8-substituted tri- and tetra-BDD/Fs, with 2,3,7,8-tetra-BDD (2,3,7,8-TeBDD) being the most strongly retained. Steady-state was not reached for tetra- to hexa-CDDs. Non-2,3,7,8-congeners showed little of or no retention. Most PCBs had high retention and did not reach steady-state. Half-lives decreased in the order: PCBs > PCDD/Fs > PBDD/Fs. Concentrations of 2,3,7,8-penta- to octa-CDD/Fs decreased with their degree of chlorination suggesting that the rate-limiting factor for uptake is low bioavailability. Maternal transfer was observed for all retained compounds, with most transfer factors < 1, indicating that transfer rates are affected by the poor water solubility of the compounds. The limited retention of the major PBDD congeners found in Baltic Sea fish suggests that they are exposed to high or very high concentrations via either food or water.
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| 5. |
- Bergman, Åke, et al.
(författare)
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Science and policy on endocrine disrupters must not be mixed : a reply to a "common sense" intervention by toxicology journal editors
- 2013
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Ingår i: Environmental Health. - : BioMed Central (BMC). - 1476-069X. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- The "common sense" intervention by toxicology journal editors regarding proposed European Union endocrine disrupter regulations ignores scientific evidence and well-established principles of chemical risk assessment. In this commentary, endocrine disrupter experts express their concerns about a recently published, and is in our considered opinion inaccurate and factually incorrect, editorial that has appeared in several journals in toxicology. Some of the shortcomings of the editorial are discussed in detail. We call for a better founded scientific debate which may help to overcome a polarisation of views detrimental to reaching a consensus about scientific foundations for endocrine disrupter regulation in the EU.
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| 6. |
- Carlsson, Gunnar, et al.
(författare)
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Comparison of embryo toxicity using two classes of aquatic vertebrates
- 2014
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Ingår i: Environmental toxicology and pharmacology. - : Elsevier BV. - 1382-6689 .- 1872-7077. ; 37, s. 24-27
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Tidskriftsartikel (refereegranskat)abstract
- Toxicity tests of musk ketone (MK) and tetrabromobisphenol-A (TBBPA) on embryos were conducted in two amphibian species, Xenopus (Silurana) tropicalis and the Swedish native species Rana arualis. TBBPA was also tested on fish embryos of Danio rerio. All species were tested in similar experimental setup. Musk ketone caused decreased heart rates at concentrations from 10 and 100 mu g/L in R. arualis and X. tropicalis, respectively. TBBPA caused effects at 1000 mu g/L in all three species. The responses were comparable between all three species which supports the relevance for using data from non-native species in national risk assessment. (C) 2013 Elsevier B.V. All rights reserved.
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| 7. |
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| 8. |
- Carlsson, Gunnar, et al.
(författare)
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Thyroid disruption properties of three indoor dust chemicals tested in Silurana tropicalis tadpoles
- 2019
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Ingår i: Journal of Applied Toxicology. - : Wiley. - 0260-437X .- 1099-1263. ; 39:9, s. 1248-1256
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Tidskriftsartikel (refereegranskat)abstract
- Indoor dust contains a multitude of industrial chemicals, and ingestion of dust is considered an important exposure route to organic contaminants. Some of these contaminants have been shown to interfere with the thyroid system, which may result in significant consequences on public health. The amphibian metamorphosis is a thyroid hormone-dependent process, which can be used as an in vivo model for studies on thyroid hormone-disrupting potency. Three contaminants of indoor dust were tested on metamorphosing Silurana (Xenopus) tropicalis tadpoles. The tested chemicals were Tris (1,3-dichloroisopropyl) phosphate (TDCiPP), tetrabromobisphenol-A (TBBPA) and propylparaben (PrP). Measurements reflecting general growth, development progress and thyroid epithelial cell height were performed on the exposed tadpoles as well as chemical analyses of the exposure water. It was shown that TDCiPP acts as a thyroid hormone-disrupting chemical in metamorphosing tadpoles by causing increased epithelial cell height in thyroid glands after exposure to a nominal concentration of 0.010 mg/L and in higher concentrations. TBBPA caused reductions in general growth of tadpoles at the nominal concentration 0.125 mg/L, and PrP caused acute toxicity at the nominal concentration 12.5 mg/L. However, no evident indications of specific thyroid-disrupting effects caused by TBBPA or PrP were observed.
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| 9. |
- Carlsson, Gunnar, et al.
(författare)
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Toxicity of 15 veterinary Pharmaceuticals in zebrafish (Danio rerio) embryos
- 2013
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Ingår i: Aquatic Toxicology. - : Elsevier BV. - 0166-445X .- 1879-1514. ; 126, s. 30-41
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Tidskriftsartikel (refereegranskat)abstract
- Extensive use of veterinary pharmaceuticals may result in contamination of water bodies adjacent to pasture land or areas where animal manure has been applied. In order to evaluate the potential risk to fish embryos 15 veterinary pharmaceuticals were investigated by use of an extended zebrafish embryo toxicity test. Chemical analysis of the exposure medium was performed by solid phase extraction-liquid chromatography-tandem mass spectrometry (SPE-LC-MS/MS) for 11 of the compounds and potential metabolism by the embryos was studied for albendazole, febantel, fenbendazole and oxfendazole. Newly fertilized zebrafish eggs were exposed under static conditions in 96-well plates for 6 days to the pharmaceuticals: 5 antibacterials and 10 antiparasitics. Endpoints including mortality, malformations and other sublethal responses were recorded at 24, 48 and 144 h post fertilization (hpf). The pharmaceuticals causing the highest toxicity were antiparasitics whereas the tested antibacterials, danofloxacin, enrofloxacin, tylosine, trimethoprim and oxytetracyclin had a much lower toxic potency in zebrafish embryos. Most toxic were fenbendazole, albendazole and flumethrin with no observed effect concentrations (NOECs) around 0.02 mg/L. The overall NOEC was determined by lethality for the following pharmaceuticals: albendazole, fenbendazole and oxfendazole. Sublethal endpoints, including malformations, side-laying embryos, tremors, reduced movements and altered heart rate increased the sensitivity of the tests and determined the overall NOECs for febantel, doramectin, ivermectin, flumethrin and toltrazuril. Exposure to doramectin and ivermectin caused a decrease in movements at 24 hpf and a decrease in heart rate at 48 hpf. Flumethrin exposure resulted in decreased time to hatching, except at the highest concentrations, and caused an increase in heart rate at 48 hpf. In contrast, toltrazuril caused an increased time to hatching and a decrease in heart rate. Chemical analysis of the exposure medium after the tests revealed great differences between nominal and measured concentrations, emphasizing the need of including analysis of the actual exposure concentrations. The results indicated that metabolism of albendazole into its sulfoxide protected the embryos from toxicity. Albendazole was metabolized efficiently into albendazole sulfoxide at lower exposure concentrations, resulting in reduced toxicity. At higher concentrations, an increasing proportion of albendazole remained unmetabolized and embryo mortality occurred. Metabolism by the embryos of febantel into fenbendazole and oxfendazole and of fenbendazole into oxfendazole was demonstrated. It is suggested that the toxic effect of febantel in zebrafish embryos is due to metabolism into fenbendazole.
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| 10. |
- Carlsson, Gunnar, et al.
(författare)
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Toxicity screening of produced water extracts in a zebrafish embryo assay
- 2014
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Ingår i: Journal of Toxicology and Environmental Health, Part A: Current Issues. - : Informa UK Limited. - 1528-7394 .- 1087-2620. ; 77, s. 600-615
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Tidskriftsartikel (refereegranskat)abstract
- Produced water is the largest effluent discharge from oil and gas/condensate production facilities in the North Sea. There is concern that contaminants originating from the reservoir and chemicals used in the production process may affect marine organisms. Developmental toxicity of extractable organic compounds in produced water effluents from oil and gas/condensate production platforms in the Norwegian sector of the North Sea was assessed in a temporal and spatial manner using zebrafish (Danio rerio) embryos. Large-scale solid-phase extraction (SPE) and on-column fractionation of water-soluble fraction (WSF) and an oil/particulate fraction was used in a rapid screening bioassay for embryotoxicity. Exposure to produced water extracts increased rate of mortality and reduced pigmentation and heart rate, as well as delaying time to hatch. The oil/particulate fraction was 10-fold less toxic than WSF, indicating that toxicity was predominantly produced by moderately polar and bioavailable compounds. Large spatial and temporal variation in produced water toxicity was observed, displaying considerable variability in the reservoir, oil well, and effluent composition over time. The noted toxicity did not correlate well with either reported produced water composition or parameters such as total hydrocarbons, thus challenging chemical measurements as a reliable source of information for predicting complex effects. Although embryotoxicity was observed following exposure to the extracts, dilution and transformation of produced water in the recipient are expected to rapidly reduce the concentrations of compounds in the effluents to levels below the thresholds of observed effects.
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| 11. |
- Caspillo, Nasim Reyhanian, 1982-
(författare)
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Hitting the mark : studies of alterations in behaviour and fertility in ethinyl estradiol-exposed zebrafish and search related biomarkers
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis, we have analysed the effects of EE2 on non-reproductive behaviours and fertility. We have showed that two doses of EE2 in male adult short-term exposures evokes opposite behaviours in the novel tank test. A lower dose induced increased bottom-dwelling, a sign of increased anxiety and a higher dose increased surface-dwelling, which would likely expose themselves to predation in a natural environment. Increased shoaling was observed in both exposures, possibly affecting feeding and reproduction opportunities. Fertility analysis of these fish demonstrated a complete inhibition of spawning in the highest dose group. To investigate mechanisms behind the spawning failure, we examined expression levels of genes involved in zebrafish sex differentiation and maintenance of gonadal function. We found downregulated transcription levels of male-predominant genes, suggesting a demasculinization of the testes contributing to functional sterility in these fish. We have demonstrated that non-reproductive behaviour in zebrafish is highly sensitive to EE2 exposure during development. After exposing male and female zebrafish to low doses of EE2 followed by remediation in clean water until adulthood, the fish displayed increased anxiety and shoaling behaviour, demonstrating persistent effects of EE2. Furthermore, behavioural effects were transferred to their progeny. Decreased fertilisation success of the developmentally exposed fish was observed in both sexes when mated to untreated animals of the opposite sex. These fertility effects persisted although the fish had a long remediation period, implying likely reduced fitness of fish populations in aquatic environments. Based on our findings on non-reproductive behaviours and fertility, we performed RNAsequencing analysis of the brain and testes in order to investigate possible biological mechanisms behind the persistent effects. There is a need for biomarkers allowing detection of both reversible and irreversible effects in animals exposed to estrogenic substances, hopefully contributing to better risk assessments for EDCs. Results from RNA-sequencing would serve as a basis for continued studies in pursuit of potential biomarkers.
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| 12. |
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| 13. |
- Engwall, Magnus, 1965-, et al.
(författare)
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Cytochrome P450IA induction by a coplanar PCB, a PAH mixture, and PCB-contaminated sediment extracts following microinjection of rainbow trout sac-fry
- 1994
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Ingår i: Aquatic Toxicology. - : Elsevier BV. - 0166-445X .- 1879-1514. ; 30:4, s. 311-324
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Tidskriftsartikel (refereegranskat)abstract
- The 7-ethoxyresorufin-O-deethylase (EROD)-inducing potencies of a coplanar polychlorinated biphenyl (PCB) (3,3',4,3',5-pentachlorobiphenyl, IUPAC No. 126), a mixture of five polycyclic aromatic hydrocarbons (benzo(k)fluoranthene, benz(a)anthracene, benzo(a)pyrene, indeno(1,2,3-cd)pyrene and chrysene), and lipophilic compounds extracted from the sediments in a PCB-contaminated lake and from sediments in lakes up- and downstream, were studied in rainbow trout sac-fry in a 43-day study. The compounds/extracts were injected into the yolk sacs of newly hatched sac-fry and hepatic EROD activities and mortality rates were measured at various times after the injections. Five livers from each group were also examined by transmission electron microscopy. All the compounds/extracts induced hepatic EROD activities in the sac-fry. Ten days after injection the EROD activity caused by PCB No. 126 (1.3 ng per embryo) was 40-fold compared to the control activity. This was the highest induction rate observed in the experiment. For the sediment extracts, the highest induction rates were observed at the first sampling occasion, which for these groups was on day 24. The extract from the Lake Jarnsjon sediment was more potent as an EROD inducer than the extracts of sediments from the lakes up- and downstream from Lake Jarnsjon. None of the sediment extracts caused any significant mortality. In sac-fry injected with the PAH mixture, EROD was only slightly induced. The highest dose of PAHs (10 mu g per embryo) caused about 90% mortality by 24 days after injection. When the livers were examined by transmission electron microscopy, morphological alterations (e.g. hepatocyte degeneration and hypertrophy) were seen in the groups injected with Lake Jarnsjon sediment extract, PCB No. 126 and the highest dose of the PAH mixture (10 mu g per embryo).
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| 14. |
- Förlin, Lars, 1950, et al.
(författare)
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A tiered test system for fish toxicity
- 2004
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Ingår i: Better chemicals control within Reach. - 9172837047 ; , s. 109-117
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 15. |
- Hellström, Anders, et al.
(författare)
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8. Aquaculture and Fish Health
- 2012. - 1
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Ingår i: Ecology and Animal Health. - Uppsala : Baltic University Press. - 9789186189129 ; , s. 63-72
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Bokkapitel (populärvet., debatt m.m.)
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| 16. |
- Hendriksen, Rene S., et al.
(författare)
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Global monitoring of antimicrobial resistance based on metagenomics analyses of urban sewage
- 2019
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- © 2019, The Author(s). Antimicrobial resistance (AMR) is a serious threat to global public health, but obtaining representative data on AMR for healthy human populations is difficult. Here, we use metagenomic analysis of untreated sewage to characterize the bacterial resistome from 79 sites in 60 countries. We find systematic differences in abundance and diversity of AMR genes between Europe/North-America/Oceania and Africa/Asia/South-America. Antimicrobial use data and bacterial taxonomy only explains a minor part of the AMR variation that we observe. We find no evidence for cross-selection between antimicrobial classes, or for effect of air travel between sites. However, AMR gene abundance strongly correlates with socio-economic, health and environmental factors, which we use to predict AMR gene abundances in all countries in the world. Our findings suggest that global AMR gene diversity and abundance vary by region, and that improving sanitation and health could potentially limit the global burden of AMR. We propose metagenomic analysis of sewage as an ethically acceptable and economically feasible approach for continuous global surveillance and prediction of AMR.
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| 17. |
- Holbech, Henrik, et al.
(författare)
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Comparison of zebrafish (Danio rerio) and fathead minnow (Pimephales promelas) as test species in the Fish Sexual Development Test (FSDT).
- 2012
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Ingår i: Comparative Biochemistry and Physiology - Part C. - : Elsevier BV. - 1532-0456 .- 1878-1659. ; 155:2, s. 407-15
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Tidskriftsartikel (refereegranskat)abstract
- Results are presented from a validation (with 5 laboratories) of the Fish Sexual Development Test (FSDT) developed to detect endocrine disrupters (EDs) and included in the OECD (Organisation for Economic Co-operation and Development) working program. The aromatase-inhibiting fungicide prochloraz was tested in zebrafish (Danio rerio) and fathead minnow (Pimephales promelas). The fish were exposed during sexual differentiation and development from 0 to 60 days post hatch (dph). After exposure, the vitellogenin (VTG) concentrations were quantified in head/tail homogenate and the sex ratio was determined (defined as female, male, intersex or undifferentiated). NOEC/LOEC and EC(x) designs were compared to optimize the test approach. Results show that both species are highly sensitive to prochloraz during sexual development. They respond by skewing of the sex ratio towards male phenotype and by a VTG decline in females. The NOEC/LOEC approach is preferred because sex ratio is difficult to analyze with a regression model. The mean NOEC/LOEC for prochloraz on the sex ratio was 43.3/134 μg/L and 101/293 μg/L for zebrafish and fathead minnow, respectively. The mean NOEC/LOEC on the decline in female VTG concentration was 65/110 μg/L and ~30/68 μg/L respectively. In conclusion, zebrafish and fathead minnow are suitable species in the FSDT and their sexual differentiation is equally labile to EDs.
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| 18. |
- Jakobsson, Christine, et al.
(författare)
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Preface
- 2012. - 1
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Ingår i: Sustainable Agriculture. - Uppsala : Baltic University Press. - 9789186189105 ; , s. 8-10
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Bokkapitel (populärvet., debatt m.m.)
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| 19. |
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| 20. |
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| 21. |
- Linderoth, Maria, et al.
(författare)
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Steroid biosynthetic enzyme activities in leachate-exposed female perch (Perca fluviatilis) as biomarkers for endocrine disruption
- 2006
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Ingår i: Science of the Total Environment. - : Elsevier B.V.. - 0048-9697 .- 1879-1026. ; 366:2-6, s. 638-648
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Tidskriftsartikel (refereegranskat)abstract
- Studies have shown that adult female perch in a freshwater lake, Molnbyggen, Sweden, have a reproductive disorder caused by unidentified endocrine disrupting compounds (EDCs) leaching from a local refuse dump. The adverse effects include shallow open sores, low ratio of sexually mature individuals, low gonadosomatic index and low circulating levels of androgens. We hypothesised that the low androgen levels could be a result of impaired production and/or stimulated excretion of androgens by EDCs. From October 2000 to November 2001, at time-points important in the perch reproductive cycle, adult female perch were collected in Molnbyggen and in the reference lake, Djursjön. The activities of three key enzymes in androgen biosynthesis: 17α-hydroxylase (17OHlase), 17,20-lyase (lyase) and 17β-hydroxysteroid dehydrogenase (17βHSD) were determined in head kidney or ovary. The relationship between enzyme activities and plasma steroid concentrations was examined. Ovarian histopathology and the determination of brain aromatase activity were also included in the study. Similar 17OHlase, 17βHSD and aromatase activities were found in Molnbyggen females and reference fish throughout the year. Head kidney 17OHlase showed a positive correlation to cortisol levels (r = 0.754; p < 0.001) but not to androgen levels. Molnbyggen females exhibited lower ovarian lyase activity during vitellogenesis than reference fish. Atretic oocytes were on most occasions more frequent in sexually immature than in sexually mature females. The results suggest that neither 17OHlase, 17βHSD nor aromatase is the target for EDCs disrupting the androgen homeostasis of exposed female perch. Further investigation is needed to establish the role of decreased ovarian lyase activity in endocrine homeostasis, but the possibility of increased excretion of androgens should also be examined.
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| 22. |
- Ljungvall, Karl, et al.
(författare)
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Sows exposed to octylphenol in early gestation: No estrogenic effects in male piglets, but increased rate of stillbirth
- 2012
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Ingår i: Theriogenology. - : Elsevier BV. - 0093-691X .- 1879-3231. ; 78, s. 1494-1499
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Tidskriftsartikel (refereegranskat)abstract
- Octylphenol is an industrial chemical with estrogenic effects both in vitro and in vivo. In this study the effects of short-term intramuscular exposure to 0.1 mg/kg of body weight and 1.0 mg/kg of body weight in early gestation were evaluated in pregnant sows with respect to reproductive parameters in the newborn male piglets, as compared with male piglets from unexposed control sows. The male piglets were examined immediately after birth with respect to the macroscopic appearance of the reproductive organs and testosterone concentration in serum. It was not possible to identify any estrogenic effects in the newborn male piglets. However, in the sows exposed at the highest level of octylphenol, there was an increased number of stillborn piglets and an increased proportion of sows with stillborn piglets in the litter (P < 0.05). This was an unexpected finding which has not been reported previously. (C) 2012 Elsevier Inc. All rights reserved.
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| 23. |
- Lundberg, G, et al.
(författare)
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Inmatning av sebrafisk, Brachydanio rerio, med halogenerade substanser extraherade från lax och ål. Studier av bioackumulering och reproduktionskapacitet.
- 1992
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Fiskoljor extraherades från ål (Anguilla anguilla) och lax (Salmo salar). Fiskarna var fångade i både förorenade och relativt opåverkade områden. Toxiciteten av oljorna samt en fraktion (triacylglyceroler och fria fettsyror) av oljorna testades med avseende på effekter orsakade av Extraherbar Organiskt bunden Klor (EOCl). Sebrafiskhonor (Brachydanio rerio) utfodrades med frystorkade mygglarver som kontaminerats med de olika fiskoljorna och fraktionerna varefter bioackumulering av EOCl och reproduktionskapacitet (antal lagda ägg och kläckningsprocent) studerades. Den fraktionerade oljan från ål fångad i ett förorenat område var mer toxisk än motsvarande fraktion från ett relativt opåverkat område. Utfodring med de ursprungliga fiskoljorna gav inga skillnader i reproduktionskapacitet trots skillnader i halten EOCl. Analyserad halt EOCl i oljorna visade god korrelation med koncentrationerna i oljorna även om upptagseffektiviteten varierade för de olika oljorna. De funna effekterna kunde inte enbart förklaras av EOCl-intaget men utfodringsförsöket visade ändå att exponering för kontaminerat foder är en relevant metod för att studera biologiska effekter orsakade av lipofila ämnen.
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| 24. |
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| 25. |
- Nieuwenhuijse, David F., et al.
(författare)
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Setting a baseline for global urban virome surveillance in sewage
- 2020
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- © 2020, The Author(s). The rapid development of megacities, and their growing connectedness across the world is becoming a distinct driver for emerging disease outbreaks. Early detection of unusual disease emergence and spread should therefore include such cities as part of risk-based surveillance. A catch-all metagenomic sequencing approach of urban sewage could potentially provide an unbiased insight into the dynamics of viral pathogens circulating in a community irrespective of access to care, a potential which already has been proven for the surveillance of poliovirus. Here, we present a detailed characterization of sewage viromes from a snapshot of 81 high density urban areas across the globe, including in-depth assessment of potential biases, as a proof of concept for catch-all viral pathogen surveillance. We show the ability to detect a wide range of viruses and geographical and seasonal differences for specific viral groups. Our findings offer a cross-sectional baseline for further research in viral surveillance from urban sewage samples and place previous studies in a global perspective.
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| 26. |
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| 27. |
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| 28. |
- Norman Haldén, Anna, et al.
(författare)
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Oral exposure of adult zebrafish (Danio rerio) to 2,4,6-tribromophenol affects reproduction
- 2010
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Ingår i: Aquatic Toxicology. - : Elsevier BV. - 0166-445X .- 1879-1514. ; 100, s. 30-37
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Tidskriftsartikel (refereegranskat)abstract
- The bromophenol 2,4,6-tribromophenol (TBP) is widely used as an industrial chemical, formed by degradation of tetrabromobisphenol-A, and it occurs naturally in marine organisms. Concentrations of TBP in fish have been related to intake via feed, but little is known about effects on fish health after oral exposure. In this study, we exposed adult male and female zebrafish (Danio rerio) to TBP via feed in nominal concentrations of 33, 330, and 3300??g/g feed (or control feed) for 6 weeks to assess the effects of TBP on reproductive output, gonad morphology, circulatory vitellogenin levels, and early embryo development. The aim was also to investigate the extent to which TBP was metabolised to 2,4,6-tribromoanisole (TBA) in dietary exposed zebrafish, and the amounts of TBP and TBA found in offspring. After 6 weeks of exposure, we found about 3% of the daily dose of TBP in adult fish and the mean concentration of TBA was 25–30% of the TBP concentration. TBP and TBA were detected in offspring with wet weight-based egg/fish concentration ratios well below one. Exposure to TBP significantly reduced the fertilization success and disturbed the gonad morphology, i.e. fewer spermatid cysts in males and increased presence of atretic follicles and oocytes with decreased vitellogenesis in females. In females, the disturbed gonad morphology was accompanied by increased levels of circulating vitellogenin. Significant effects were observed at 3300??g/g feed. Offspring early development was not significantly affected, but yolk-sac oedema tended to increase in frequency in exposed groups with time. Our results show that dietary exposure to TBP, at concentrations found in marine organisms that are part of the natural diet of wild fish, can interfere with reproduction in zebrafish. We also observed low accumulation from feed of TBP in zebrafish and biotransformation of TBP to TBA. This is the first paper showing gonadal histopathological changes and effects on fertility in TBP exposed fish
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| 29. |
- Norman Haldén, Anna, et al.
(författare)
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Retention and maternal transfer of brominated dioxins in zebrafish (Danio rerio) and effects on reproduction, aryl hydrocarbon receptor-regulated genes, and ethoxyresorufin-O-deethylase (EROD) activity
- 2011
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Ingår i: Aquatic Toxicology. - Oxford : Elsevier. - 0166-445X .- 1879-1514. ; 102:3-4, s. 150-161
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Tidskriftsartikel (refereegranskat)abstract
- Brominated dioxins have recently been detected in Baltic Sea biota. Due to their similarities to the highly toxic chlorinated dioxins, concern has been raised about their potential biological effects. The present study investigated retention and effects of brominated dioxins in adult zebrafish, as well as maternal transfer and effects on offspring. We exposed adult zebrafish for nine weeks via feed to 2,3,7,8-tetrabromodibenzo-p-dioxin (TBDD) or to a mixture of brominated dioxins (Baltic Sea mixture), which was designed to reflect relative concentrations found in Baltic Sea biota. We studied spawning success, gonad morphology, hepatic vitellogenin gene expression, and offspring early life-stage development to investigate effects on zebrafish reproduction. Hepatic ethoxyresorufin-O-deethylase (EROD) activity and hepatic expression of a number of aryl hydrocarbon receptor (AHR)-regulated genes were studied to investigate if the brominated dioxins can activate gene transcription through the AHR pathway in zebrafish. In addition, glutathione reductase activity and expression of genes involved in adaptive responses to intracellular stress were studied to investigate potential stress effects of brominated dioxins. After nine weeks of exposure, all brominated dioxins spiked to the feed were detected in female fish and transferred to eggs. Exposure to the Baltic Sea mixture and TBDD clearly induced AHR-regulated genes and EROD activity. Exposure to TBDD reduced spawning success, altered ovarian morphology and reduced hepatic vitellogenin gene expression, which implies that TBDD has a similar effect pattern as the chlorinated analogue. Overall, our results show that dietary exposure to sublethal concentrations of brominated dioxins may impair reproductive physiology in fish and induce AHR-regulated genes. (C) 2011 Elsevier B.V. All rights reserved.
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| 30. |
- Norrgren, Kristina, et al.
(författare)
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Comparative renal, hepatic, and bone marrow toxicity of Cisplatin and radioactive Cisplatin (191Pt) in Wistar rats
- 2006
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Ingår i: Cancer Biotherapy and Radiopharmaceuticals. - : Mary Ann Liebert Inc. - 1084-9785 .- 1557-8852. ; 21:5, s. 528-534
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the study was to investigate the possibility to increase the therapeutic gain of the cytotoxic agent, cisplatin, by incorporation of radioactive platinum. In this study, we investigated how organs at risk (i.e., kidneys, bone marrow, and liver) are affected by treatment with 191Pt-cisplatin, compared to treatment with conventional cisplatin. Rats (total, n = 69) were divided into three groups and given 5 mg/kg 191Pt-cisplatin and 5 mg/kg nonradioactive cisplatin or saline. The weight of the animals and blood samples, including analysis of creatinine, bilirubin, alanine and aspartate aminotransferases and platelet count, was followed for 6 weeks after treatment. Histopathology examinations of kidney and liver tissues were performed. An initial decrease in weight gain was seen from 3 days after treatment with cisplatin and 191Pt-cisplatin and for 1 week onward; thereafter, the weight gain continued, following the same pattern as for the control group. Concentration of plasma creatinine was increased for both cisplatin groups but with no significant difference between treatment groups. No other significant differences in effect parameters were found. There was no increase in toxicity for radioactive cisplatin on liver, kidneys, and bone marrow, compared to conventional cisplatin. Further experimental and clinical studies on preparations of this type are thus warranted.
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| 31. |
- Norrgren, Leif
(författare)
-
33. Remediation of Lake Järnsjön, Sweden
- 2012. - 2
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Ingår i: Ecology and Animal Health. - Uppsala : Baltic University Press. - 9789186189129 ; , s. 265-267
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Bokkapitel (populärvet., debatt m.m.)
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| 32. |
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| 33. |
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| 34. |
- Norrgren, Leif
(författare)
-
Occurrence of oestrogenic pollutants and widespread feminisation of male tilapia in peri-urban dams in Bulawayo, Zimbabwe
- 2018
-
Ingår i: African Journal of Aquatic Science. - : National Inquiry Services Center (NISC). - 1608-5914 .- 1727-9364. ; 43, s. 17-26
-
Tidskriftsartikel (refereegranskat)abstract
- Peri-urban water bodies are at risk from excessive pollution as they are direct sinks for urban effluents. The occurrence of oestrogenic and androgenic endocrine disrupting chemicals (EDCs) in effluents and water bodies around the city of Bulawayo, Zimbabwe, and their effects on wild fish was investigated in 2013. Effluent and water were sampled from sewage treatment plants, an urban stream, and effluent-polluted dams, and were compared with a 'pristine' dam upstream of Bulawayo. Organic pollutants were extracted by solid-phase extraction and tested for EDCs using a yeast oestrogen/androgen screen. Oestrogenic and androgenic potencies were expressed as 17-oestradiol equivalent (EEq) or dihydrotestosterone equivalent (TEq). Tilapia and catfish from the dams were analysed for gonado-somatic indices and testis histopathology. Effluents from STPs, which directly flow into Umguza Dam, had EEq of 33 ng l(-1) and 55 ng l(-1), respectively. Umguza Dam, Khami Dam and Matsheumhlope Stream had EEqs of 237 ng l(-1), 9 ng l(-1) and 2 ng l(-1), respectively. Androgenic activity was detected in only one STP (TEq = 93 ng l(-1)). Tilapia sampled from effluent-polluted dams had high incidences of testis-ova, but catfish had no signs of reproductive dysfunction. These findings underscore the need for greater attention to EDCs in developing countries where there is scant literature regarding their occurrence and impacts.
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| 35. |
- Norrgren, Leif
(författare)
-
Optimizing the design of a reproduction toxicity test with the pond snail Lymnaea stagnalis
- 2016
-
Ingår i: Regulatory Toxicology and Pharmacology. - : Elsevier BV. - 0273-2300 .- 1096-0295. ; 81, s. 47-56
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents the results from two ring-tests addressing the feasibility, robustness and reproducibility of a reproduction toxicity test with the freshwater gastropod Lymnaea stagnalis (RENILYS strain). Sixteen laboratories (from inexperienced to expert laboratories in mollusc testing) from nine countries participated in these ring-tests. Survival and reproduction were evaluated in L. stagnalis exposed to cadmium, tributyltin, prochloraz and trenbolone according to an OECD draft Test Guideline. In total, 49 datasets were analysed to assess the practicability of the proposed experimental protocol, and to estimate the between-laboratory reproducibility of toxicity endpoint values. The statistical analysis of count data (number of clutches or eggs per individual-day) leading to ECx estimation was specifically developed and automated through a free web-interface. Based on a complementary statistical analysis, the optimal test duration was established and the most sensitive and cost-effective reproduction toxicity endpoint was identified, to be used as the core endpoint. This validation process and the resulting optimized protocol were used to consolidate the OECD Test Guideline for the evaluation of reproductive effects of chemicals in L stagnalis. (C) 2016 Elsevier Inc. All rights reserved.
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| 36. |
- Näslund, Johanna, et al.
(författare)
-
Diclofenac affects kidney histology in the three-spined stickleback (Gasterosteus aculeatus) at low mu g/L concentrations
- 2017
-
Ingår i: Aquatic Toxicology. - : Elsevier BV. - 0166-445X .- 1879-1514. ; 189, s. 87-96
-
Tidskriftsartikel (refereegranskat)abstract
- Diclofenac, a commonly used non-steroidal anti-inflammatory drug, is considered for regulation under the European water framework directive. This is because effects on fish have been reported at concentrations around those regularly found in treated sewage effluents (similar to 1 mu g/L). However, a recent publication reports no effects on fish at 320 mu g/L. In this study, three-spined sticklebacks (Gasterosteus aculeatus) were exposed to 0, 4.6, 22, 82 and 271 mu g/L diclofenac in flow-through systems for 28 days using triplicate aquaria per concentration. At the highest concentration, significant mortalities were observed already after 21 days (no mortalities found up to 22 mu g/L). Histological analysis revealed a significant increase in the proportion of renal hematopoietic tissue (renal hematopoietic hyperplasia) after 28 days at the lowest concentration and at all higher concentrations, following a clear dose-response pattern. Skin ulcerations of the jaw were noted by macroscopic observations, primarily at the two highest concentrations. No histological changes were observed in the liver. There was an increase in the relative hepatic mRNA levels of c7 (complement component 7), a gene involved in the innate immune system, at 22 mu g/L and at all higher concentrations, again following a clear dose-response. The bio-concentration factor was stable across concentrations, but lower than reported for rainbow trout, suggesting lower internal exposure to the drug in the stickleback. In conclusion, this study demonstrates that diclofenac causes histological changes in the three-spined stickleback at low mu g/L concentrations, which cause concern for fish populations exposed to treated sewage effluents.
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| 37. |
- Näslund, Johanna, et al.
(författare)
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Naproxen affects multiple organs in fish but is still an environmentally better alternative to diclofenac
- 2020
-
Ingår i: Aquatic Toxicology. - : Elsevier BV. - 0166-445X .- 1879-1514. ; 227
-
Tidskriftsartikel (refereegranskat)abstract
- © 2020 The Author(s) The presence of diclofenac in the aquatic environment and the risks for aquatic wildlife, especially fish, have been raised in several studies. One way to manage risks without enforcing improved wastewater treatment would be to substitute diclofenac (when suitable from a clinical perspective) with another non-steroidal anti-inflammatory drug (NSAID) associated with less environmental risk. While there are many ecotoxicity-studies of different NSAIDs, they vary extensively in set-up, species studied, endpoints and reporting format, making direct comparisons difficult. We previously published a comprehensive study on the effects of diclofenac in the three-spined stickleback (Gasterosteus aculeatus). Our present aim was to generate relevant effect data for another NSAID (naproxen) using a very similar setup, which also allowed direct comparisons with diclofenac regarding hazards and risks. Sticklebacks were therefore exposed to naproxen in flow-through systems for 27 days. Triplicate aquaria with 20 fish per aquarium were used for each concentration (0, 18, 70, 299 or 1232 μg/L). We investigated bioconcentration, hepatic gene expression, jaw lesions, kidney and liver histology. On day 21, mortalities in the highest exposure concentration group unexpectedly reached ≥ 25 % in all three replicate aquaria, leading us to terminate and sample that group the same day. On the last day (day 27), the mortality was also significantly increased in the second highest exposure concentration group. Increased renal hematopoietic hyperplasia was observed in fish exposed to 299 and 1232 μg/L. This represents considerably higher concentrations than those expected in surface waters as a result of naproxen use. Such effects were observed already at 4.6 μg/L in the experiment with diclofenac (lowest tested concentration). Similar to the responses to diclofenac, a concentration-dependent increase in both relative hepatic gene expression of c7 (complement component 7) and jaw lesions were observed, again at concentrations considerably higher than expected in surface waters. Naproxen bioconcentrated less than diclofenac, in line with the observed effect data. An analysis of recent sales data and reported concentrations in treated sewage effluent in Sweden suggest that despite higher dosages used for naproxen, a complete substitution would only be expected to double naproxen emissions. In summary, naproxen and diclofenac produce highly similar effects in fish but the environmental hazards and risks are clearly lower for naproxen. Hence, if there are concerns for environmental risks to fish with diclofenac, a substitution would be advisable when naproxen presents an adequate alternative from a clinical point-of-view.
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| 38. |
- Pohl, Johannes, et al.
(författare)
-
Effects of ozonated sewage effluent on reproduction and behavioral endpoints in zebrafish (Danio rerio)
- 2018
-
Ingår i: Aquatic Toxicology. - : Elsevier BV. - 0166-445X .- 1879-1514. ; 200, s. 93-101
-
Tidskriftsartikel (refereegranskat)abstract
- Pharmaceutical residues and other micro-contaminants may enter aquatic environments through effluent from sewage treatment plants (STPs) and could cause adverse effects in wild fish. One strategy to alleviate this situation is to improve wastewater treatment by ozonation. To test the effectiveness of full-scale wastewater effluent ozonation at a Swedish municipal STP, the added removal efficiency was measured for 105 pharmaceuticals. In addition, gene expression, reproductive and behavioral endpoints were analyzed in zebrafish (Danio rerio) exposed on-site over 21 days to ozonated or non-ozonated effluents as well as to tap water. Ozone treatment (7 g O-3/m(3)) removed pharmaceuticals by an average efficiency of 77% in addition to the conventional treatment, leaving 11 screened pharmaceuticals above detection limits. Differences in biological responses of the exposure treatments were recorded in gene expression, reproduction and behavior. Hepatic vitellogenin gene expression was higher in male zebrafish exposed to the ozonated effluent compared to the non-ozonated effluent and tap water treatments. The reproductive success was higher in fish exposed to ozonated effluent compared to non-ozonated effluent and to tap water. The behavioral measurements showed that fish exposed to the ozonated STP effluent were less active in swimming the first minute after placed in a novel vessel. Ozonation is a capable method for removing pharmaceuticals in effluents. However, its implementation should be thoroughly evaluated for any potential biological impact. Future research is needed for uncovering the factors which produced the in vivo responses in fish.
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| 39. |
- Pohl, Johannes, et al.
(författare)
-
Embryotoxicity of ozonated diclofenac, carbamazepine, and oxazepam in zebrafish (Danio rerio)
- 2019
-
Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 225, s. 191-199
-
Tidskriftsartikel (refereegranskat)abstract
- Pharmaceutical residues are polluting the surface water environments worldwide. Sewage and wastewater treatment, therefore, needs to be improved in order to remove pharmaceutical residues from the effluent. One such treatment improvement is effluent ozonation. Even though ozonation has proven to be very efficient in reducing pharmaceutical parent compound concentrations in wastewater effluents, much remains unclear regarding potentially toxic ozonation by-product (OBP) formation. In this study, we sought to elucidate the aquatic toxicity of ozonated pharmaceuticals in zebrafish (Danio rerio) embryos in a static 144 h post fertilization (hpf) fish embryotoxicity (ZFET) assay. Three pharmaceuticals commonly detected in wastewater effluents, i.e. carbamazepine, diclofenac, and oxazepam, were selected for testing. Toxicity was assessed before and after 1 min ozonation (0.053 mg L-1 peak O-3 concentration) and 10 min ozonation (0.147 mg L-1 peak O-3 concentration). Chemical analysis showed that carbamazepine and diclofenac were largely removed by ozone (90 +/- 11% and 97 +/- 3.8%), whereas oxazepam was removed to a lesser extent (19 +/- 5.7%). The ZFET assay revealed diverging toxicities. Diclofenac embryotoxicity decreased with increasing ozonation. Oxazepam did not cause embryotoxicity in the ZFET assay either pre- or post ozonation, but larvae swimming activity was affected at 144 hpf. Carbamazepine embryotoxicity, on the other hand, increased with increasing ozonation. Chemical analysis showed the formation of two OBPs (carbamazepine-10,11-epoxide and 10,11-dihydrocarbamazepine), possibly explaining the increased embryotoxicity. The results of this study highlight the importance of new chemical and toxicological knowledge regarding the formation of OBPs in post-ozonated effluents. (C) 2019 The Authors. Published by Elsevier Ltd.
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| 40. |
- Pohl, Johannes, et al.
(författare)
-
Toxicological evaluation of water from stormwater ponds using Xenopus tropicalis embryos
- 2015
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Ingår i: Wetlands Ecology and Management. - : Springer Science and Business Media LLC. - 0923-4861 .- 1572-9834. ; 23, s. 1091-1098
-
Tidskriftsartikel (refereegranskat)abstract
- The establishment of stormwater ponds for treatment of runoff water can be beneficial for amphibians due to creations of new habitats which often develop vegetative characteristics similar to that of natural wetlands. These ponds might help to promote stability in amphibian populations if the benefits of creation of new habitats exceed the risk for toxic impact. In the present study, Swedish stormwater ponds were searched for larval amphibians. Further, the impact of stormwater quality on embryo development was tested using Xenopus (Silurana) tropicalis. Data suggest that most of the studied stormwater ponds had water of proper quality for promoting amphibian embryo development. However there were sites in which the water caused premature hatching and/or reduced heart rate in X. tropicalis embryos. Pollutant toxicity might be one explanation for sublethal effects caused by some of the stormwater samples. In a majority of ponds, no amphibian larvae were detected and this may partly be explained by toxic compounds in the waters.
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| 41. |
- Rattfelt Nyholm, Jenny, et al.
(författare)
-
Maternal transfer of brominated flame retardants in zebrafish (Danio rerio)
- 2008
-
Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 73:2, s. 203-208
-
Tidskriftsartikel (refereegranskat)abstract
- In many species reproduction and embryonic development have been shown to be sensitive to environmental contaminants. Understanding embryonic exposure to environmental contaminants is thus highly important. In this study concentrations of brominated flame retardants (BFRs) were measured in zebrafish eggs after parental exposure for 42 days via the diet. Zebrafish were exposed to two doses of eleven structurally-diverse BFRs. Eight BFRs were detected in the female zebrafish and maternal transfer to eggs was evident for all eight compounds. The highest concentrations in eggs were observed for hexabromocyclododecane (HBCD) and 2,4,4′-tribromodiphenyl ether (BDE 28), followed by 2,2′,3,4,4′,5′,6-heptabromodiphenyl ether (BDE 183) and tetrabromobisphenol A 2,3-dibromopropyl ether (TBBPA DBPE). Five potential BFR metabolites were tentatively identified in female fish and maternal transfer was observed also for these compounds. The lipid adjusted concentrations in eggs were significantly higher than the concentrations in female fish for several of the BFRs. Further, the results showed a generally higher transfer in the lower exposure level and also indicated a dependency on the physico-chemical properties of the compounds.
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| 42. |
- Rattfelt Nyholm, Jenny, et al.
(författare)
-
Uptake and biotransformation of structurally-diverse brominated flame retardants in zebrafish (Danio Rerio) after dietary exposure
- 2009
-
Ingår i: Environmental Toxicology and Chemistry. - Hoboken : John Wiley & Sons. - 0730-7268 .- 1552-8618. ; 28:5, s. 1035-1042
-
Tidskriftsartikel (refereegranskat)abstract
- Zebrafish (Danio rerio) were fed a diet containing a mixture of 11 structurally diverse brominated flame retardants (BFRs) at nominal concentrations of either 1 or 100 nmol/g for up to 42 d, followed by an elimination period of 14 d. Uptake rates and elimination constants for five of the BFRs were calculated from measurements of their concentrations in the male fish during the exposure and elimination phases. Observed uptake efficiencies were highest for 2,4,4′-tribromodiphenyl ether (BDE 28) and 1,2-dibromo-4-(1,2-dibromoethyl)cyclohexane (TBECH) and were lowest for decabromodiphenyl ether (BDE 209). Estimated half-lives for TBECH and 2,4,6-tribromophenol were short (<2 d). Four BFR metabolites were identified in the fish: 2,2′,3,4′,5′,6-Hexabromodiphenyl ether (BDE 149), 2,2′,4,4′,5,6′-hexabromodiphenyl ether (BDE 154), 2,4,6-tribromoanisole, and 1,2,4,5-hexabromobenzene. These metabolites were still present in the zebrafish after the 14-d elimination period. No relationship between the BFR concentrations in the zebrafish and their log octanol-water partition coefficient (KOW) values was found. Generally, low tendencies to bioaccumulate were observed for perbrominated and hydroxylated compounds. The observed accumulation of BFR metabolites in fish, however, shows that low concentration of a BFR does not provide, in isolation, a sound indication that the BFR poses low risks.
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| 43. |
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| 44. |
- Svenson, Anders, et al.
(författare)
-
Östrogena effekter av kommunala och industriella avloppsvatten i Sverige
- 2000
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Östrogena effekter har undersökts i 18 kommunala reningsverk med varierande metoder för rening och tolv industriutsläpp. Kommunala avloppsvatten innehåller ämnen med östrogena effekter. Uppmätta effekter i utgående, behandlade avloppsvatten motsvarade
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| 45. |
- Ul haq, Mazhar, et al.
(författare)
-
Comparison of developmental toxicity of seven perfluoroalkyl acids to zebrafish embryos
- 2013
-
Ingår i: Environmental toxicology and pharmacology. - : Elsevier BV. - 1382-6689 .- 1872-7077. ; 36, s. 423-426
-
Tidskriftsartikel (refereegranskat)abstract
- The toxicity of individual perfluoroalkyl acids (PFAAs) has been suggested to be determined by the carbon chain length as well as the functional group attached. We tested seven different PFAAs including both sulfonic and carboxylic PFAAs with different chain length to evaluate the developmental toxicity in zebrafish embryos. Generally, the acute toxicity of PFAAs is relatively low to zebrafish embryos. The EC50 values ranged from 1.5 to 2200 mg/L. We observed a relationship between higher toxicity with longer carbon chain. In addition, we also observed a higher toxicity for sulfonic PFAAs than for carboxylic PFAAs. (C) 2013 Elsevier B.V. All rights reserved.
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| 46. |
- Ul haq, Mazhar, et al.
(författare)
-
Locomotor behavior in zebrafish (Danio rerio) larvae exposed to perfluoroalkyl acids
- 2013
-
Ingår i: Aquatic Toxicology. - : Elsevier BV. - 0166-445X .- 1879-1514. ; 144, s. 332-340
-
Tidskriftsartikel (refereegranskat)abstract
- Perfluoroalkyl acids (PFAAs) are persistent organic contaminants that have been detected in wildlife, humans and the environment. Studies have shown that the toxicity of PFAAs is determined by the carbon chain length as well as the attached functional group. The locomotor activity of zebrafish larvae has become widely used for evaluation of chemicals with neurotoxic properties. In the present study the behavioral effects of seven structurally different PFAAs (i.e. TFAA, PFBA, PFOA, PFNA, PFDA, PFBS and PFOS) were evaluated in zebrafish larvae. Exposure to high concentrations of TFAA, PFNA, PFBS and PFOS resulted in distinct changes in behavioral patterns. Based on redundancy analysis, our results demonstrate three main factors affecting zebrafish larval locomotor behavior. The strongest effect on behavior was determined by the carbon chain length and the attached functional group. PFAAs with longer carbon chain length as well as PFAAs with attached sulfonic groups showed larger potential to affect locomotor behavior in zebrafish larvae. Also the concentration of the PFAAs determined the behavior responses. The results of the present study are in agreement with previous studies showing correlations between the chemical structure of PFAAs and the toxicological effects. (C) 2013 Elsevier B.V. All rights reserved.
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| 47. |
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| 48. |
- Ulhaq, Mazhar, et al.
(författare)
-
Tissue uptake, distribution and elimination of C-14-PFOA in zebrafish (Danio rerio)
- 2015
-
Ingår i: Aquatic Toxicology. - : Elsevier BV. - 0166-445X .- 1879-1514. ; 163, s. 148-157
-
Tidskriftsartikel (refereegranskat)abstract
- Perfluorooctanoic acid (PFOA) is a long-chain perfluorinated chemical that has been shown to be non-degradable and persistent in the environment. Laboratory studies on bioconcentration and compound-specific tissue distribution in fish can be valuable for prediction of the persistence and environmental effects of the chemicals. In the present study male and female zebrafish (Danio redo) were continuously exposed to 10 mu g/L of radiolabeled perfluorooctanoic acid (C-14-PFOA) for 40 days, after which the exposed fish were transferred to fresh clean water for another 80 days wash-out period. At defined periodic intervals during the uptake and wash-out, fish were sampled for liquid scintillation counting and whole body autoradiography to profile the bioconcentration and tissue distribution of PFOA. The steady-state concentration of C-14-PFOA in the zebrafish was reached within 20-30 days of exposure. The concentration-time course of C-14-PFOA displayed a bi-exponential decline during washout, with a terminal half-life of approximately 13-14 days. At steady-state the bioconcentration of C-14-PFOA into whole-body fish was approximately 20-30 times greater than that of the exposure concentration, with no differences between females and males. The bioconcentration factors for liver and intestine were approximately 100-fold of the exposure medium, while in brain, ovary and gall bladder the accumulation factors were in the range 15-20. Whole-body autoradiograms confirmed the highest labeling of PFOA in bile and intestines, which implies enterohepatic circulation of PFOA. The C-14-PFOA was also observed in maturing vitellogenic oocytes, suggesting chemical accumulation via yolk proteins into oocytes with plausible risk for adverse effects on early embryonic development and offspring health. The bioconcentration at several C-14-PFOA exposure concentrations were also investigated (0.3-30 mu g/L). This showed that bioconcentration increased linearly with tank exposure in the present in vivo model under steady-state conditions. From this model tissue concentrations of PFOA can be predicted when the external exposure level is known. The present study has generated experimental data on PFOA kinetics in zebrafish that can be valuable for aquatic environmental risk assessment.
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| 49. |
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| 50. |
- Örn, Stefan, et al.
(författare)
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Sexual disruption in zebrafish (Danio rerio) exposed to mixtures of 17α-ethinylestradiol and 17β-trenbolone
- 2016
-
Ingår i: Environmental toxicology and pharmacology. - : Elsevier BV. - 1382-6689 .- 1872-7077. ; 41, s. 225-231
-
Tidskriftsartikel (refereegranskat)abstract
- Environmental estrogens and androgens can be present simultaneously in aquatic environments and thereby interact to disturb multiple physiological systems in organisms. Studies on interaction effects in fish of androgenic and estrogenic chemicals are limited. Therefore, the aim of the present study was to evaluate feminization and masculinization effects in zebrafish (Danio rerio) exposed to combinations of two synthetic steroid hormones detected in environmental waters: the androgen 17 beta-trenbolone (Tb) and the oestrogen 17 alpha-ethinylestradiol (EE2). Juvenile zebrafish were exposed between days 20 and 60 post-hatch to different binary mixtures of Tb (1, 10, and 50 ng/L) and EE2 (2 and 5 ng/L). The endpoints studied were whole-body homogenate vitellogenin concentration at 40 days post-hatch, and sex ratio including gonad maturation at 60 days post-hatch. The feminizing potency of 5 ng/L of EE2, alone as well as in combination with Tb, was clear in the present study, with exposures resulting in almost all-female populations and females being sexually immature. Masculinization effects with male-biased sex ratios were observed when fish were exposed to 2 ng/L of EE2 in combination with Tb concentrations. Intersex fish were observed after exposure to mixtures of 2 ng/L EE2 with 50 ng/L Tb. Sexual maturity generally increased among males at increasing concentrations of Tb. The results of the present study show that exposure to environmentally relevant mixtures of an oestrogen and androgen affects the process of gonad differentiation in zebrafish and lead to sexual disruption. (C) 2015 Elsevier B.V. All rights reserved.
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