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  • 1.
    Bighiu, Maria Alexandra
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Watermann, Burkard
    Guo, Xueli
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Carney Almroth, Bethanie
    Eriksson-Wiklund, Ann-Kristin
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Mortality and histopathological effects in harbour-transplanted snails with different exposure histories2017In: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514, Vol. 190, p. 11-20Article in journal (Refereed)
    Abstract [en]

    Contaminants are important stressors in the aquatic environment and may exert selective pressures on organisms. We hypothesized that snails originating from a metal-contaminated habitat (B) would have increased tolerance to harbour contaminants (e.g. metals from antifouling paints), compared to snails originating from a relatively clean habitat (A). We assessed tolerance to metals in terms of survival and histopathological alterations after 2, 4 and 8 weeks of in situ exposure in three Baltic Sea boat harbours and three reference sites. We also hypothesized that any potential tolerance to contaminants would be associated with differences in genetic diversity between the two snail populations (evaluated as mitochondrial cytochrome c oxidase subunit I, COI). The results show that snails from population A survived to a higher extent compared to population B, possibly indicating either a lack of adaptation to metals in snails B or impaired health condition due to contaminant pre-exposure or a higher resilience of snails A. Moreover, the genetic diversity of COI was low within each population and did not differ between populations. In general, 83% of all the types of histopathological alterations (e.g. lysis and necrosis of gonads and digestive gland or granulocytoma and phagocytosis in the storage tissue, among others) had a higher probability of occurrence among harbour-exposed snails compared to reference exposed snails, regardless of snail population origin. The only significant difference in histological effects between the two populations was in the frequency of parasite infestations and shell fouling, both being larger for population A than B. Interestingly, the rate of parasite infestations was higher for males than females from population A, whereas no sexual dichotomy was observed for population B. Our results show that exposure to harbour contaminants causes both lethal and sublethal toxicity to snails, and the association between many of the toxic responses and metals substantiates that antifouling substances contribute to the observed effects, although there is a large proportion of variation in our data that remains unexplained.

  • 2.
    Bradshaw, Clare
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Meseh, Dina A.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Alasawi, Hiba
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Qiang, Ma
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Snoeijs-Leijonmalm, Pauline
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Nascimento, Francisco J. A.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Joint effects of gamma radiation and cadmium on subcellular-, individual-and population-level endpoints of the green microalga Raphidocelis subcapitata2019In: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514, Vol. 211, p. 217-226Article in journal (Refereed)
    Abstract [en]

    Interpreting and predicting the combined effects of toxicants in the environment is an important challenge in ecotoxicology. How such effects are connected across different levels of biological organisation is an additional matter of uncertainty. Such knowledge gaps are particularly prominent with regards to how ionising radiation interacts with contaminants. We assessed the response of twelve endpoints at the subcellular, individual and population level in a green microalga when exposed singly and jointly to gamma radiation and cadmium (Cd). We used a fully factorial experimental design where observed effects were compared to those predicted by the Independent Action (IA) model for mixture toxicity to determine whether they deviated from additivity. Subcellular endpoints (e.g., catalase, thiamine diphosphate, xanthophyll cycle pigments) showed an increased antioxidant and/or photoprotective response. However, our results indicate that this protection was not sufficient to prevent lipid peroxidation, which also increased with dose. At ecologically relevant doses, most interactions between gamma radiation and Cd regarding subcellular-, individual- and population-level endpoints were additive as predicted by the IA model. However, exposure to binary mixtures displayed antagonistic interactions between gamma radiation and Cd at the higher end of the tested dose spectrum. No correlations were observed between subcellular endpoints and higher-level endpoints, but there were linkages between individual and population endpoints. Our results suggest that antagonistic interactions between gamma radiation and Cd can occur at higher doses and that these interactions seem to disseminate from subcellular and individual to population level. Possible consequences for aquatic primary production and food-web interactions are discussed.

  • 3.
    Broman, Elias
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Motwani, Nisha H.
    Bonaglia, Stefano
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. University of Southern Denmark, Denmark.
    Landberg, Tommy
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Nascimento, Francisco J. A.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Sjöling, Sara
    Denitrification responses to increasing cadmium exposure in Baltic Sea sediments2019In: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514, Vol. 217, article id 105328Article in journal (Refereed)
    Abstract [en]

    Benthic ecosystems have come under intense pressure, due to eutrophication-driven oxygen decline and industrial metal contamination. One of the most toxic metals is Cadmium (Cd), which is lethal to many aquatic organisms already at low concentrations. Denitrification by facultative anaerobic microorganisms is an essential process to transform, but also to remove, excess nitrate in eutrophied systems. Cd has been shown to decrease denitrification and sequester free sulfide, which is available when oxygen is scarce and generally inhibits complete denitrification (i.e. N2O to N2). In polluted sediments, an interaction between oxygen and Cd may influence denitrification and this relationship has not been studied. For example, in the Baltic Sea some sediments are double exposed to both Cd and hypoxia. In this study, we examined how the double exposure of Cd and fluctuations in oxygen affects denitrification in Baltic Sea sediment. Results show that oxygen largely regulated N2O and N2 production after 21 days of exposure to Cd (ranging from 0 to 500 μg/L, 5 different treatments, measured by the isotope pairing technique (IPT)). In the high Cd treatment (500 μg/L) the variation in N2 production increased compared to the other treatments. Increases in N2 production are suggested to be an effect of 1) enhanced nitrification that increases NO3− availability thus stimulating denitrification, and 2) Cd successfully sequestrating sulfide (yielding CdS), which allows for full denitrification to N2. The in situ field sediment contained initially high Cd concentrations in the pore water (∼10 μg/L) and microbial communities might already have been adapted to metal stress, making the effect of low Cd levels negligible. Here we show that high levels of cadmium pollution might increase N2 production and influence nitrogen cycling in marine sediments.

  • 4.
    Ericson, Hanna
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Thorsen, Gunnar
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Kumblad, Linda
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Physiological effects of diclofenac, ibuprofen and propranolol on Baltic Sea blue mussels2010In: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514, Vol. 99, no 2, p. 223-231Article in journal (Refereed)
    Abstract [en]

    Pharmaceuticals are constantly dispersed into the environment and little is known of the effects on non-target organisms. This is an issue of growing concern. In this study, Baltic Sea blue mussels, Mytilus edulis trossulus, were exposed to diclofenac, ibuprofen and propranolol, three pharmaceuticals that are produced and sold in large quantities and have a widespread occurrence in aquatic environments. The mussels were exposed to pharmaceuticals in concentrations ranging from 1 to 10,000 mu g l(-1). The pharmaceuticals were added both separately and in combination. Mussels exposed to high concentrations of pharmaceuticals showed a clear response compared to controls. Firstly, they had a significantly lower scope for growth, which indicates that the organisms had a smaller part of their energy available for normal metabolism, and secondly, they had lower byssus strength and lower abundance of byssus threads, resulting in reduced ability to attach to the underlying substrate. Mussels exposed to lower concentrations showed tendencies of the same results. The concentration of diclofenac and propranolol was quantified in the mussels using both liquid chromatography coupled to mass spectrometry (LC-MS). The measurements showed a significantly higher concentration in the organisms as compared to the water the mussels were exposed to; the uptake reached concentrations two orders of magnitudes higher than found in sewage treatment plant effluents. This study showed that common pharmaceuticals are taken up and negatively affect the physiology of a non-target species at levels of two to three orders of magnitudes higher than found in sewage treatment plant effluents.

  • 5.
    Gardeström, Johanna
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Dahl, Ulrika
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Kotsalainen, Ola
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Maxson, Anders
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Elwing, Tina
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Grahn, Mats
    Bengtsson, Bengt-Erik
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Breitholtz, Magnus
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Evidence of population genetic effects of long-term exposure to contaminated sediments: A multi-endpoint study with copepods2008In: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514, Vol. 86, no 3, p. 426-436Article in journal (Refereed)
    Abstract [en]

    In the environment, pollution generally acts over long time scales and exerts exposure of multiple toxicants on the organisms living there. Recent findings show that pollution can alter the genetics of populations. However, few of these studies have focused on long-term exposure of mixtures of substances. The relatively short generation time (ca. 4–5 weeks in sediments) of the harpacticoid copepod Attheyella crassa makes it suitable for multigenerational exposure studies. Here, A. crassa copepods were exposed for 60 and 120 days to naturally contaminated sediments (i.e., Svindersviken and Trosa; each in a concentration series including 50% contaminated sediment mixed with 50% control sediment and 100% contaminated sediment), and for 120 days to control sediment spiked with copper. We assayed changes in FST (fixation index), which indicates if there is any population subdivision (i.e., structure) between the samples, expected heterozygosity, percent polymorphic loci, as well as abundance. There was a significant decrease in total abundance after 60 days in both of the 100% naturally contaminated sediments. This abundance bottleneck recovered in the Trosa treatment after 120 days but not in the Svindersviken treatment. After 120 days, there were fewer males in the 100% naturally contaminated sediments compared to the control, possibly caused by smaller size of males resulting in higher surface: body volume ratio in contact with toxic chemicals. In the copper treatment there was a significant decrease in genetic diversity after 120 days, although abundance remained unchanged. Neither of the naturally contaminated sediments (50 and 100%) affected genetic diversity after 120 days but they all had high within treatment FST values, with highest FST in both 100% treatments. This indicates differentiation between the replicates and seems to be a consequence of multi-toxicant exposure, which likely caused selective mortality against highly sensitive genotypes. We further assayed two growth-related measures, i.e., RNA content and cephalothorax length, but none of these endpoints differed between any of the treatments and the control. In conclusion, the results of the present study support the hypothesis that toxicant exposure can reduce genetic diversity and cause population differentiation. Loss of genetic diversity is of great concern since it implies reduced adaptive potential of populations in the face of future environmental change

  • 6.
    Gorokhova, Elena
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Löf, Marie
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Halldorsson, Halldor Palmar
    Tjärnlund, Ulla
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Lindström, Magnus
    Elfwing, Tina
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Sundelin, Brita
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Single and combined effects of hypoxia and contaminated sediments on the amphipod Monoporeia affinis in laboratory toxicity bioassays based on multiple biomarkers2010In: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514, Vol. 99, no 2, p. 263-274Article in journal (Refereed)
    Abstract [en]

    In estuaries, hypoxic conditions and pollution are among the major factors responsible for the declines in habitat quality, yet little is known about their combined effects on estuarine organisms. In this study, to investigate single and combined effects of hypoxia and contaminated sediment, the Baltic amphipod Monoporeia affinis was exposed for 5-9 days to four different combinations of oxygen conditions (moderate hypoxia vs. normoxia) and contamination (polluted vs. unpolluted sediments) at environmentally realistic levels. To detect oxidative stress, a suite of biomarkers was used - antioxidant enzymes [superoxide dismutases (SOD), catalase (CAT), and glutathione S-transferases (GST)], acetylcholinesterase (AChE), lipid peroxidation status (TBARS concentration), protein carbonyl content (PCC), and DNA strand breakage (DNA-SB). To assay effects at the organism level, we used RNA:DNA ratio as a proxy for growth and metabolic rate and mortality. There were significant increases in CAT and SOD activities and TBARS levels in response to both moderate hypoxia and contaminated sediment, while GST increased and AChE decreased in response to the contamination only. Significant positive correlations were observed among the antioxidant enzymes and between the enzyme activities and TBARS concentration, suggesting a complex response to the oxidative stress. No significant changes in PCC were recorded in any of the treatments. Furthermore, the negative effect of hypoxia on DNA integrity was significant; with frequency of DNA-SB increasing in animals exposed to hypoxia in contaminated sediment. Despite clear effect at the cellular and biochemical levels, no responses at the organism level were observed. Multivariate analyses of the dataset have allowed us to link exposure factors to individual biomarker responses. Of the potential biomarkers assessed in this study, CAT activity was found to be associated with hypoxia, while SOD, GST and AChE activities appear to predict best the effects of exposure to sediments containing several contaminants (e.g. heavy metals, PCBs and PAHs), and TBARS concentration is particularly indicative of combined effects of hypoxia and contamination. In addition to providing new knowledge on the combined effects of multiple stressors on estuarine organisms, the findings of the present study are also important to understand data from biomonitoring studies in the Baltic Sea and in other regions where multiple stress factors co-occur.

  • 7.
    Gorokhova, Elena
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Löf, Marie
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Reutgard, Martin
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Lindström, Magnus
    Sundelin, Brita
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Exposure to contaminants exacerbates oxidative stress in amphipod Monoporeia affinis subjected to fluctuating hypoxia2013In: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514, Vol. 127, p. 46-53Article in journal (Refereed)
    Abstract [en]

    Fitness and survival of an organism depend on its ability to mount a successful stress response when challenged by exposure to damaging agents. We hypothesized that co-exposure to contaminants may exacerbate oxidative stress in hypoxia-challenged benthic animals compromising their ability to recover upon reoxygenation. This was tested using the amphipod Monoporeia affinis exposed to hypoxia followed by reoxygenation in sediments collected in polluted and pristine areas. In both sediment types, oxygen radical absorbance capacity (ORAC) and antioxidant enzyme activities [superoxide dismutase (SOD) and catalase (CAT)] increased during hypoxia, suggesting that M. affinis has a strategy of preparation for oxidative stress that facilitates recovery after a hypoxic episode. Exposure to contaminants altered this anticipatory response as indicated by higher baselines of ORAC and SOD during hypoxia and no response upon reoxygenation. This coincided with significantly elevated oxidative damage evidenced by a marked reduction in glutathione redox status (ratio of reduced GSH/oxidized GSSG) and an increase in lipid peroxidation (TSARS levels). Moreover, RNA:DNA ratio, a proxy for protein synthetic activity, decreased in concert with increased TBARS, indicating a linkage between oxidative damage and fitness. Finally, inhibited acetylcholinesterase (AChE) activity in animals exposed to contaminated sediments suggested a neurotoxic impact, whereas significant correlations between AChE and oxidative biomarkers may indicate connections with redox state regulation. The oxidative responses in pristine sediments suggested a typical scenario of ROS production and removal, with no apparent oxidative damage. By contrast, co-exposure to contaminants caused greater increase in antioxidants, lipid peroxidation, and slowed recovery from hypoxia as indicated by CAT, GSH/GSSG, TBARS and AChE responses. These results support the hypothesized potential of xenobiotics to hamper ability of animals to cope with fluctuating hypoxia. They also emphasize the importance of understanding interactions between antioxidant responses to different stressors and physiological mechanisms of oxidative damage.

  • 8.
    Hahlbeck, Edda
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Griffiths, Richard
    Bengtsson, Bengt-Erik
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    The juvenile three-spined stickleback (Gasterosteus aculeatus L.) as a model organism for endocrine disruption I: Sexual differentiation2004In: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514, Vol. 70, no 4, p. 287-310Article in journal (Refereed)
    Abstract [en]

    Juvenile three-spined stickleback (Gasterosteus aculeatus L.) is introduced as a unique model organism for both androgenic and oestrogenic endocrine action. Intersex is often used as an indicator for disruption of sexual differentiation in fish exposed to different kinds of effluents from human activities. In wild fish it has exclusively been reported in terms of feminisation due to xenoestrogens in the environment. The assumption that the intersex individuals are feminised genetic males can only be proven by genetic sex identification of the intersexual individuals. Intersex and gonadal sex reversal were induced in three-spined sticklebacks by treatment with natural and synthetic steroid hormones. Juvenile sticklebacks were exposed to three nominal concentrations of 17β-oestradiol (E2); i.e. 0.01, 1.0 and 10.0 μg/L; which were administered to the water either continuously from hatching to the end of the experiment (39–58 days post hatch), during the first 2 weeks after hatching only, from 14 days after hatching onwards, or during the chorionated embryo stage until hatching. Other groups were exposed to 17α-ethinylestradiol (EE2) at 0.05 μg/L and 17α-methyltestosterone (MT) at 1.0 μg/L (nominal concentrations). MT was applied continuously, during the first 2 weeks post hatch only, or from 14 days after hatching onwards. Gonad histology was examined and the genetic sex was identified with male sex-linked PCR markers. Treatment with oestrogens caused feminisation at the two highest E2 concentrations and with EE2. Exposure to E2 before hatching had no effect. Intersexual individuals from oestrogen treatments were genetic males. The genetic sex marker identified apparent total reversal of the gonad type of genetic males. Treatment with MT did not reveal a clear picture, since intersex was observed in both genetic females and males. MT also caused severe testis abnormalities, mainly the development of large branched cavities with unidentified origin. The process of sex differentiation is most sensitive to the influence of external steroids during the first 2 weeks after hatching. A lower incidence of intersex could also be induced in sticklebacks exposed from 14 days after hatching by E2 treatment, but not with MT. The combination of gonad histopathology with genetic sex identification in juvenile sticklebacks is suggested as a tool for detecting endocrine disruption in laboratory studies, and might become very useful in field surveys.

  • 9.
    Hahlbeck, Edda
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Katsiadaki, Ioanna
    Mayer, Ian
    Adolfsson-Erici, Margaretha
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    James, Jonathan
    Bengtsson, Bengt-Erik
    The juvenile three-spined stickleback (Gasterosteus aculeatus L.) as a model organism for endocrine disruption II: kidney hypertrophy, vitellogenin and spiggin induction2004In: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514, Vol. 70, no 4, p. 311-326Article in journal (Refereed)
    Abstract [en]

    This study investigated the suitability of juvenile three-spined sticklebacks, Gasterosteus aculeatus L., for detecting both androgen- and oestrogen-induced endocrine disruption. The investigated endpoints were kidney hypertrophy and the induction of the protein markers spiggin and vitellogenin. Juveniles were exposed to steroid hormones 17β-oestradiol (E2: nominal 0.01, 1.0 and 10 μg/L), 17α-ethinylestradiol (EE2: nominal 0.05 μg/L) and 17α-methyltestosterone (MT: nominal 1.0 μg/L) from the day of hatching until the termination of the experiments between 39 and 58 days after hatching. E2 (10 μg/L) and MT were applied during different time windows: (a) 14 days after hatching only and (b) continuously with start 14 days after hatching.

    Kidney hypertrophy is an androgen-dependent secondary sexual character in adult male sticklebacks and corresponds to the production of the glue protein spiggin during the breeding season. The kidneys were hypertrophied and spiggin levels were elevated in juvenile sticklebacks after treatment with MT. Paradoxically, slightly elevated spiggin levels and kidney hypertrophy were observed also in fish treated with high dose E2. Levels of vitellogenin, the oestrogen-inducible yolk precursor protein, were elevated in juvenile sticklebacks after E2 medium and high dose and EE2 treatment.

    The tested endpoints are suitable for the study of endocrine disruption in juvenile sticklebacks, a fish species that is easy to handle in laboratory and relevant for temperate geographical regions.

  • 10. Huang, Susie S. Y.
    et al.
    Benskin, Jonathan P.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Veldhoen, Nik
    Chandramouli, Bharat
    Butler, Heather
    Helbing, Caren C.
    Cosgrove, John R.
    A multi-omic approach to elucidate low-dose effects of xenobiotics in zebrafish (Danio rerio) larvae2017In: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514, Vol. 182, p. 102-112Article in journal (Refereed)
    Abstract [en]

    Regulatory-approved toxicity assays_such as the OECD Fish Embryo Toxicity Assay (TG236) allow correlation of chemical exposure to adverse morphological phenotypes. However, these assays are ineffective in assessing sub-lethal (i.e. low-dose) effects, or differentiating between similar phenotypes induced by different chemicals. Inclusion of multi-omic analyses in studies investigating xenobiotic action provides improved characterization of biological response, thereby enhancing prediction of toxicological outcomes in whole animals in the absence of morphological effects. In the current study, we assessed perturbations in both the metabolome and transcriptome of zebrafish (Danio rerio; ZF) larvae exposed from 96 to 120 h post fertilization to environmental concentrations of acetaminophen (APAP), diphenhydramine (DH), carbamazepine (CBZ), and fluoxetine (FLX); common pharmaceuticals with known mechanisms of action. Multi-omic responses were evaluated independently and integrated to identify molecular interactions and biological relevance of the responses. Results indicated chemical-and dose-specific changes suggesting differences in the time scale of transcript abundance and metabolite production. Increased impact on the metabolome relative to the transcriptome in FLX-treated animals suggests a stronger post-translational effect of the treatment. In contrast, the transcriptome showed higher sensitivity to perturbation in DH-exposed animals. Integration of `omic' responses using multivariate approaches provided additional insights not obtained by independent `omic' analyses and demonstrated that the most distinct overall response profiles were induced following low-dose exposure for all 4 pharmaceuticals. Importantly, changes in transcript abundance corroborated with predictions from metabolomic enrichment analyses and the identified perturbed biological pathways aligned with known xenobiotic mechanisms of action. This work demonstrates that a multi-omic toxicological approach, coupled with a sensitive animal model such as ZF larvae, can help characterize the toxicological relevance of acute low-dose chemical exposures.

  • 11.
    Jacobson, Therese
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Holmström, Katrin
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Yang, Gongda
    Ford, Alex T.
    Berger, Urs
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Sundelin, Brita
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Perfluorooctane sulfonate accumulation and parasite infestation in a field population of the amphipod Monoporeia affinis after microcosm exposure2010In: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514, Vol. 98, no 1, p. 99-106Article in journal (Refereed)
    Abstract [en]

    Perfluorooctane sulfonate (PFOS) is the focus of intense toxicity research due to its persistence and widespread occurrence in biota. Studies on benthic invertebrates have shown them to be subjects of high PFOS exposure. However, effects on benthic invertebrates exposed to PFOS in the field are still far from elucidated. To fill a knowledge gap on concentrations and effects in benthic invertebrates, a microcosm study on the benthic amphipod Monoporeia affinis was performed. Field collected M. affinis were analysed for PFOS and showed average background concentrations 39 and 58 ng/g (wet weight) in two different samplings. The field collected animals were exposed to three concentrations of PFOS (50, 200 and 5000 μg PFOS/L water) for 3 weeks during gonad development. Body burdens of PFOS were determined after experiment termination. Results showed negative effects on survival and reproduction effects such as decreased sexual maturation and decreased oocyte viability caused by PFOS exposure. Additionally, a follow-up experiment demonstrated a significant increase in the infection incidence by a microsporidian muscle parasite in animals exposed to PFOS at tissue concentrations in the range of concentrations found in field collected benthic amphipods. This is the first study to demonstrate increased microsporidian infection with pollutant exposure and it suggests that ecologically relevant PFOS concentrations could be sufficient to elicit these effects.

  • 12.
    Jacobson, Therese
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Sundelin, Brita
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Yang, Gongda
    Ford, Alex T.
    Low dose TBT exposure decreases amphipod immunocompetence and reproductive fitness2011In: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514, Vol. 101, no 1, p. 72-77Article in journal (Refereed)
    Abstract [en]

    The antifouling agent tributyltin (TBT) is a highly toxic pollutant present in many aquatic ecosystems. Despite of regulations on the usage of TBT, it remains in high concentrations in sediments both in harbors and in off-shore sites. The toxicity of TBT in mollusks is well documented. However, adverse effects in other aquatic organisms, such as crustaceans, are less well known. This study is an effort to assess the effects of environmentally realistic concentrations of TBT on an ecologically important species in Swedish fresh and brackish water ecosystems, the benthic amphipod Monoporeia affinis. Field collected animals were exposed during gonad maturation to TBT (70 and 170 ng/g sediment d wt) for five weeks in static microcosms with natural sediment. Exposure concentrations were chosen to reflect effects at concentrations found in Swedish coastal sediment, but below expected effects on survival. TBT exposure resulted in a statistically significant adverse effect on oocyte viability and a doubling of the prevalence of microsporidian parasites in females, from 17% in the control to 34% in the 170 ng TBT/g sediment d wt exposure. No effects on survival were observed. Borderline significant effects were observed on male sexual maturation in the 70 ng TBT/g d wt exposure and on ecdysteroid levels in the 170 ng/g sediment d wt exposure. Both reproduction and parasite infection effects are of ecological importance since they have the potential to affect population viability in the field. This study gives further evidence to the connection between low dose contaminant exposure and increases in microsporidian parasite infection.

  • 13.
    Lage, Sandra
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Reis Costa, Pedro
    Moita, Teresa
    Eriksson, Johan
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Rasmussen, Ulla
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Jonasson Rydberg, Sara
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    BMAA in shellfish from two Portuguese transitional water bodies suggests the marine dinoflagellate Gymnodinium catenatum as a potential BMAA source2014In: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514, Vol. 152, p. 131-138Article in journal (Refereed)
    Abstract [en]

    The neurotoxin -N-methylamino-l-alanine (BMAA) and its putative role in multiple neurodegenera-tive diseases have been intensely studied since 2005 when the toxin was discovered to be producedby worldwide-distributed cyanobacterial species inhabiting terrestrial, marine, brackish, and freshwaterecosystems. Recently, BMAA production was also associated with one eukaryotic group, namely, diatoms,raising questions about its production by other phytoplanktonic groups. To test for BMAA bioavailabilityin ecosystems where abundant phytoplanktonic blooms regularly occur, samples of filter-feeding shell-fish were collected in two Portuguese transitional water bodies. BMAA content in cockles (Cerastodermaedule) collected weekly between September and November 2009 from Ria de Aveiro and at least once amonth from May to November from Ria Formosa, fluctuated from 0.079 ± 0.055 to 0.354 ± 0.066 g/g DWand from below the limit of detection to 0.434 ± 0.110 g/g DW, respectively. Simultaneously to BMAAoccurrence in cockles, paralytic shellfish toxins were detected in shellfish as a result of Gymnodiniumcatenatum blooms indicating a possible link between this marine dinoflagellate and BMAA production.Moreover, considerable high BMAA levels, 0.457 ± 0.186 g/g DW, were then determined in a laboratorygrown culture of G. catenatum. This work reveals for the first time the presence of BMAA in shellfishfrom Atlantic transitional water bodies and consubstantiate evidences of G. catenatum as one of the mainsources of BMAA in these ecosystems.

  • 14. Lammel, Tobias
    et al.
    Wassmur, Britt
    Mackevica, Aiga
    Chen, Chang-Er L.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. South China Normal University, China.
    Sturve, Joachim
    Mixture toxicity effects and uptake of titanium dioxide (TiO2) nanoparticles and 3,3 ',4,4 '-tetrachlorobiphenyl (PCB77) in juvenile brown trout following co-exposure via the diet2019In: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514, Vol. 213, article id 105195Article in journal (Refereed)
    Abstract [en]

    Titanium dioxide nanoparticles (n-TiO2) are among the man-made nanomaterials that are predicted to be found at high concentrations in the aquatic environment. There, they likely co-exist with other chemical pollutants. Thus, n-TiO2 and other chemical pollutants can be taken up together or accumulate independently from each other in prey organisms of fish. This can lead to dietary exposure of fish to n-TiO2-chemical pollutant mixtures. In this study, we examine if simultaneous dietary exposure to n-TiO2 and 3,3',4,4'-Tetrachlorobiphenyl (PCB77)-used as a model compound for persistent organic pollutants with dioxin-like properties-can influence the uptake and toxicological response elicited by the respective other substance. Juvenile brown trout (Salmo trutta) were fed custom-made food pellets containing n-TiO2, PCB77 or n-TiO2+PCB77 mixtures for 15 days. Ti and PCB77 concentrations in the liver were measured by ICP-MS and GC-MS, respectively. Besides, n-TiO2 uptake was assessed using TEM. Combination effects on endpoints specific for PCB77 (i.e., cytochrome P450 1A (CYP1A) induction) and endpoints shared by both PCB77 and n-TiO2 (i.e., oxidative stress-related parameters) were measured in intestine and liver using RT-qPCR and enzyme activity assays. The results show that genes encoding for proteins/enzymes essential for tight junction function (zo-1) and ROS elimination (sod-1) were significantly upregulated in the intestine of fish exposed to n-TiO2 and PCB77 mixtures, but not in the single-substance treatments. Besides, n-TiO2 had a potentiating effect on PCB77-induced CYP1A and glutathione reductase (GR) expression/enzyme activity in the liver. This study shows that simultaneous dietary exposure to nanomaterials and traditional environmental pollutants might result in effects that are larger than observed for the substances alone, but that understanding the mechanistic basis of such effects remains challenging.

  • 15. Larsson, D.G.J.
    et al.
    Adolfsson-Erici, M.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Parkkonen, J.
    Pettersson, Maria
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Berg, A.H.
    Olsson, P.-E.
    Förlin, L.
    Ethinyloestradiol – an undesired fish contraceptive?1999In: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514, Vol. 45, no 2-3, p. 91-97Article in journal (Refereed)
    Abstract [en]

    Environmental oestrogens are natural or synthetic substances present in the environment, which imitate the effects of endogenous oestrogen. Oestrogenic substances were identified by gas chromatography/mass spectrometry in effluent water from a Swedish sewage treatment works receiving mainly domestic wastewater. Substances found include the synthetic oestrogen used in contraceptives 17 alpha-ethinyloestradiol (4.5 ng l(-1)), the natural oestrogens oestrone (5.8 ng l(-1)) and 17 beta-oestradiol (1.1 ng l(-1)), and the weaker non-steroidal oestrogens 4-nonylphenol (840 ng l(-1)) and bisphenol A (490 ng l(-1)). Ethinyloestradiol exceeded levels shown to be oestrogenic to fish by 45 times. The oestrogenicity of the effluent water was investigated by introducing juvenile rainbow trout (Oncorhynchus mykiss) in cages downstream of the sewage treatment works. After 2 weeks, all oestrogens indicated were present in the bile of the fish, and the oestrogen inducible protein, vitellogenin, was found in large amounts in the plasma (1.5 mg ml(-1)), as determined by enzyme-linked immunosorbent assay and Western blotting. Thus, a widely used synthetic oestrogen affects the endocrine systems of fish exposed to sewage effluent water.

  • 16.
    Linderoth, Maria
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Ledesma, Maria
    Zebühr, Yngve
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Environmental Chemistry.
    Balk, Lennart
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Environmental Chemistry.
    Sex steroids in the female zebrafish (Danio rerio). Effects of cyproterone acetate and leachate-contaminated sediment extract2006In: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514, Vol. 79, no 2, p. 192-200Article in journal (Refereed)
    Abstract [en]

    In Molnbyggen, a leachate-contaminated lake in Sweden, effects on the reproductive system of perch included a decreased frequency of sexually mature female perch, reduced gonadosomatic index and decreased plasma levels of androstenedione and testosterone, but the contaminants responsible for these effects have not yet been identified. A biomarker-directed fractionation approach could be used to narrow the search for the compound(s) responsible for the adverse effects in Molnbyggen female perch. Thus, it is important to develop and test a suitable biomarker, which can be used in this type of approach. We evaluated if decreased concentrations of sex steroids could work as an in vivo end-point in female zebrafish fed an organic extract of bottom sediments from Molnbyggen. The responsiveness of zebrafish to endocrine alteration was evaluated using a positive control substance, cyproterone acetate (CA), which is known to inhibit steroid biosynthesis. After the 21-day exposure period the concentrations of testosterone (T) and estradiol (E2) were successfully determined by HRGC/HRMS in whole-body homogenates of individual fish. Median T concentrations were 1.7 pmol/g fish in controls and were decreased after exposure both to CA (0.55 pmol/g fish) and Molnbyggen sediment extract (1.2–1.3 pmol/g fish). Median E2 concentrations were 5.3 pmol/g fish in controls and were decreased after CA exposure (2.3 pmol/g fish) and after exposure to Molnbyggen sediment extract (4.0–4.5 pmol/g fish). This suggests that sex steroid concentrations in zebrafish are responsive to endocrine alteration and indicates that compounds with endocrine altering potency are present in Molnbyggen sediments.

  • 17.
    Lundström Belleza, Elin
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Brinkmann, Markus
    Preuss, Thomas G.
    Breitholtz, Magnus
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Population-level effects in Amphiascus tenuiremis: Contrasting matrix- and individual-based population models2014In: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514, Vol. 157, p. 207-214Article in journal (Refereed)
    Abstract [en]

    Environmental risk assessment (ERA) is generally based on individual-level endpoints, even though protection goals in ERA intend higher biological levels. Population models have the potential to translate individual-level endpoints to population-level responses and range from simple demographic equations to highly complex individual based models (IBMs). The aims of the current study were to develop a matrix model (MM) with the structure and parameterization proposed in the draft OECD guideline Harpacticoid copepod development and reproduction test with Amphiascus tenuiremis, and an IBM with the same data requirements. Experimental data from lindane exposure from validation studies of the OECD guideline was projected to the population level. Lindane does not only cause effects on survival and reproduction, but also on the time it takes to develop from larvae to adults. The two model approaches were contrasted in terms of their ability to properly project these effects on development. The MM projected smaller effects of the lindane treatments on population growth rate compared to the IBM since in its proposed structure, it did not include the delay in development explicitly. Population-level EC10 for population growth rate in the IBM was at the same level as the most sensitive individual-level endpoint, whereas the EC10 from the MM was not as sensitive. Based on these findings, our conclusion is that the IBM (or an improved MM) should be used for datasets including shifts in development, whereas the simpler MM is sufficient for datasets where only mortality and reproduction are affected, or as a screening tool in lower-tier population-level ERA.

  • 18.
    Lundström Belleza, Elin
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Brinkmann, Markus
    RWTH Aachen University, Institute for Environmental Research, Department of Ecosystem Analysis, Worringerweg 1, D-520 74, Aachen, Germany.
    Preuss, Thomas G.
    RWTH Aachen University, Institute for Environmental Research, Chair of Environmental Biology and Chemodynamics, Worringerweg 1, D-520 74, Aachen, Germany.
    Breitholtz, Magnus
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Population-level effects in Amphiascus tenuiremis: Contrasting simple and complex population modelsIn: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514Article in journal (Refereed)
  • 19.
    Lundström, Elin
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Björlenius, Berndt
    Brinkmann, Markus
    Hollert, Henner
    Persson, Jan-Olov
    Stockholm University, Faculty of Science, Department of Mathematics.
    Breitholtz, Magnus
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Comparison of six sewage effluents treated with different treatment technologies-Population level responses in the harpacticoid copepod Nitocra spinipes.2010In: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514, Vol. 96, no 4, p. 298-307Article in journal (Refereed)
    Abstract [en]

    Since conventional treatment technologies may fail in removing many micro-pollutants, there is currently a focus on the potential of additional treatment technologies for improved sewage treatment. The aim of the present study was to evaluate six different effluents from Henriksdal Sewage Treatment Plant in Stockholm, Sweden. The effluents were; conventionally treated effluent (chemical phosphorous removal in combination with an activated sludge process, including biological nitrogen removal and a sand filter), with additional treatments individually added to the conventional treatment; active carbon filtration, ozonation at 5mgl(-1), ozonation at 15mgl(-1), ozonation at 5mgl(-1)+moving bed biofilm reactor and irradiation with ultraviolet radiation+hydrogen peroxide. The evaluation was done by characterizing and comparing the effluents using a Lefkovitch matrix model based on a life cycle test with the harpacticoid copepod Nitocra spinipes, combined with analysis of juvenile development and survival over time. The conventionally treated effluent resulted in the most negative effects, leading to the conclusion that all additional treatments in the present study created effluents with less negative impacts on the copepod populations. The ozone treatments with the low dose treatment in particular, resulted in the overall least negative effects. Moving bed biofilm reactor combined with ozone did not improve the quality of the effluent in the sense that slightly more negative effects on the population abundance were seen for this treatment technology compared to ozonation alone. The active carbon treatment had more negative effects than the ozone treatments, most of which could possibly be explained by removal of essential metal ions. The effluent which was treated with ultraviolet radiation+hydrogen peroxide resulted in few developmental and survival effects over time, but still showed negative effects on the population level. Matrix population modeling proved a useful tool for biologically characterizing and comparing the effluents. Basing the assessment either on the individual level data (development and survival over time or total reproductive output) or the population level data (lambda values and projected population abundances) would not have resulted in the same conclusions as combining both analyses. The juvenile development and survival over time allowed for closer monitoring of the important molting process, whereas the population modeling provided an integrated measure of potential effects at the population level. If the dilution of the effluent in the recipient is considered, the biological effects recorded in the present study were not of substantial significance for the copepod populations, regardless of treatment technology.

  • 20. Noaksson, Erik
    et al.
    Linderoth, Maria
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Tjärnlund, Ulla
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Balk, Lennart
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Toxicological effects and reproductive impairments in female perch (Perca fluviatilis) exposed to leachate from Swedish refuse dumps2005In: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514, Vol. 75, no 2, p. 162-177Article in journal (Refereed)
    Abstract [en]

    We have previously found that leachate from a Swedish refuse dump caused toxicological effects, including endocrine disruption and reproductive failures, in feral female perch (Perca fluviatilis) from Molnbyggen and in brook trout (Salvelinus fontinalis) from Vadbäcken. This raised concerns that leachate-induced toxicity might affect fish in other leachate-contaminated lakes. This study looks at female perch from three different regions in Sweden, focusing on toxicological biomarkers (skin lesions, liver-somatic index (LSI), ethoxyresorufin O-deethylase (EROD) activity and DNA adducts) and reproductive biomarkers (number of mature females, gonadosomatic index (GSI), aromatase (P450arom), progesterone, 17α-hydroxyprogesterone (17α-OHP), testosterone (T) and 17β-estradiol (E2)). Five out of seven contaminated locations had lower numbers of mature females and most of them exhibited higher frequencies of fin erosion relative to their comparable reference sites. Females from Lake Nedre Vättern exhibited these effects, as well as body sores, high EROD activity, high levels of DNA adducts in the liver and the intestinal mucosa, low GSI and low plasma levels of T and E2, similar to the anti-estrogenic effects earlier found in SM perch from Molnbyggen in 1997 and in brook trout from Vadbäcken. No effects on LSI, GSI, aromatase, or circulating steroids were found in mature females from Molnbyggen in this study. This indicated less leachate-contamination, but low numbers of mature females in Lake Siljan, at the sewage treatment plant which now processes the leachate that earlier contaminated Molnbyggen and Vadbäcken, suggested insufficient sewage treatment at this site. All females in Lake Simshyttsjön were mature, and their high GSI and LSI, low EROD activity, high level of 17α-OHP and low level of T, suggest an estrogenic rather than an anti-estrogenic effect. The results show that our earlier findings in Molnbyggen and Vadbäcken are not common, but neither are they unique. This study also shows that refuse dumps should be considered as potential point-sources for environmental pollutants, and that uncontrolled leachate-contamination of lakes and freshwater reservoirs could be a serious environmental hazard for both wildlife and humans.

  • 21.
    Näslund, Johan
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Hedman, Jenny E.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Agestrand, Cecilia
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Effects of the antibiotic ciprofloxacin on the bacterial community structure and degradation of pyrene in marine sediment2008In: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514, Vol. 90, no 3, p. 223-7Article in journal (Refereed)
    Abstract [en]

    The ecological consequences of antibiotics in the aquatic environment have been an issue of concern over the past years due to the potential risk for negative effects on indigenous microorganisms. Microorganisms provide important ecosystem services, such as nutrient recycling, organic matter mineralization and degradation of pollutants. In this study, effects of exposure to the antibiotic ciprofloxacin on the bacterial diversity and pollutant degradation in natural marine sediments were studied using molecular methods (T-RFLP) in combination with radiorespirometry. In a microcosm experiment, sediment spiked with (14)C-labelled pyrene was exposed to five concentrations of ciprofloxacin (0, 20, 200, 1000 and 2000 microgL(-1)) in a single dose to the overlying water. The production of (14)CO(2) (i.e. complete mineralization of pyrene) was measured during 11 weeks. Sediment samples for bacterial community structure analysis were taken after 7 weeks. Results showed a significant dose-dependent inhibition of pyrene mineralization measured as the total (14)CO(2) production. The nominal EC(50) was calculated to 560 microgL(-1), corresponding to 0.4 microg/kg d.w. sediment. The lowest effect concentration on the bacterial community structure was 200 microgL(-1), which corresponds to 0.1 microg/kg d.w. sediment. Our results show that antibiotic pollution can be a potential threat to both bacterial diversity and an essential ecosystem service they perform in marine sediment.

  • 22.
    Reutgard, Martin
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Furuhagen, Sara
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Linking sub-cellular biomarkers to embryo aberrations in the benthic amphipod Monoporeia affinis2016In: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514, Vol. 173, p. 36-42Article in journal (Refereed)
    Abstract [en]

    To adequately assess and monitor environmental status in the aquatic environment a broad approach is needed that integrates physical variables, chemical analyses and biological effects at different levels of the biological organization. Embryo aberrations in the Baltic Sea key species Monoporeia affinis can be induced by both metals and organic substances as well as by hypoxia, increasing temperatures and malnutrition. This amphipod has therefore been used for more than three decades as a biological effect indicator in monitoring and assessment of chemical pollution and environmental stress. However, little is known about the sub-cellular mechanisms underlying embryo aberrations. An improved mechanistic understanding may open up the possibility of including sub-cellular alterations as sensitive warning signals of stress-induced embryo aberrations. In the present study, M. affinis was exposed in microcosms to 4 different sediments from the Baltic Sea. After 88-95 days of exposure, survival and fecundity were determined as well as the frequency and type of embryo aberrations. Moreover, oxygen radical absorption capacity (ORAC) was assayed as a proxy for antioxidant defense, thiobarbituric acid reactive substances (TBARS) level as a measure of lipid peroxidation and acetylcholinesterase (AChE) activity as an indicator of neurotoxicity. The results show that AChE and ORAC can be linked to the frequency of malformed embryos and arrested embryo development. The occurrence of dead broods was significantly associated with elevated TBARS levels. It can be concluded that these sub-cellular biomarkers are indicative of effects that could affect Darwinian fitness and that oxidative stress is a likely mechanism in the development of aberrant embryos in M. affinis.

  • 23. Rimayi, Cornelius
    et al.
    Odusanya, David
    Weiss, Jana M.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Swedish University of Agricultural Sciences, Sweden.
    de Boer, Jacob
    Chimuka, Luke
    Mbajiorgu, Felix
    Effects of environmentally relevant sub-chronic atrazine concentrations on African clawed frog (Xenopus laevis) survival, growth and male gonad development2018In: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514, Vol. 199, p. 1-11Article in journal (Refereed)
    Abstract [en]

    Sub-chronic toxicity of environmentally relevant atrazine concentrations on exposed tadpoles and adult male African clawed frogs (Xenopus laevis) was evaluated in a quality controlled laboratory for 90 days. The aim of this study was to determine the effects of atrazine on the survival, growth and gonad development of African clawed frogs. After exposure of tadpoles to atrazine concentrations of 0 (control), 0.01, 200 and 500 mu g L-1 in water, mortality rates of 0, 0, 3.3 and 70% respectively were recorded for the 90 day exposure period. Morphometry showed significantly reduced tadpole mass in the 500 mu g L-1 atrazine exposed tadpoles (p < 0.05). Light microscopy on testes of adult frogs exposed to the same atrazine concentrations using hematoxylin and eosin (H&E) and Van Gieson staining techniques revealed gonadal atrophy, disruption of germ cell lines, seminiferous tubule structure damage and formation of extensive connective tissue around seminiferous tubules of frogs exposed to 200 mu g L-1 and 500 mu g L-1 atrazine concentrations. Ultrastructural analysis of the cellular organelles using transmission electron microscopy (TEM) revealed significant amounts of damaged mitochondria in testosterone producing Leydig cells as well as Sertoli cells. Biochemical analysis revealed reduced serum testosterone levels in adult frogs at all exposure levels as well as presence of six atrazine metabolites in frog serum and liver. The results indicate that atrazine concentrations greater than the calculated LC50 of 343.7 mu g L-1 cause significant mortality in tadpoles, while concentrations >= 200 mu g L-1 adversely affect reproductive health of adult frogs and development of tadpoles sub-chronically exposed to atrazine.

  • 24.
    Tedengren, Michael
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Olsson, Björne
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Reimer, O
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Brown, D.C.
    Bradley, B.P.
    Heat pretreatment increase cadmium resistance and HSP 70 levels in Baltic Sea mussels2000In: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514, Vol. 48, no 1, p. 1-12Article in journal (Refereed)
    Abstract [en]

    The effects of heat treatment and cadmium exposure on the synthesis of a major stress inducible protein (hsp 70) and on the metabolism of the blue mussel Mytilus edulis L. from the Baltic Sea, were studied in a laboratory experiment. The mussels were kept in sea water of ambient salinity (6.3‰) and temperature (4°C). The effects of cadmium (20 μg l−1), measured as changes in physiological rates (oxygen consumption, ammonia excretion, clearance rates and scope for growth) and hsp 70 expression were studied at 4°C and in combination with a rapid rise in temperature to 20°C. Relatively low levels of hsp 70 were detected but the negative effect was reflected in a reduction of scope for growth of the exposed mussels compared to controls. This effect was more pronounced at 20°C. Mussels not exposed to cadmium in the first experiment were used in a second set of experiments. Heat shocked mussels were allowed to reacclimatise to 4°C for 5 days and then, along with the mussels already at 4°C, exposed to cadmium (20 μg l−1). The results clearly indicated that the mussels exposed to 20°C in the first experiment more rapidly induced synthesis of hsp 70 after cadmium exposure in the second experiment. Also the reacclimatised mussels exposed to heat shock but not to cadmium in the first experiment, induced some hsp 70 in the second experiment. This suggests that the rate of induction of heat shock or stress proteins in Baltic mussels is slower than what has been described for mussels from more marine environments. The mussels kept at 4°C throughout the experiment and exposed to cadmium showed low levels of hsp 70, again indicating a low rate of induction. The increasing levels of hsp 70 correlated well with a maintained level of physiological fitness, in terms of scope for growth, although the mussels showed increasing body burdens of cadmium.

  • 25.
    Ulfsdotter Turesson, Eva
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Stiernström, Sara
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Minten, Johanna
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Adolfsson-Erici, Margaretha
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Bengtsson, Bengt-Erik
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Breitholtz, Magnus
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Development and reproduction of the freshwater harpacticoid copepod Attheyella crassa for assessing sediment-associated toxicity2007In: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514, Vol. 83, no 3, p. 180-9Article in journal (Refereed)
    Abstract [en]

    Both freshwater and marine sediments are sinks for many anthropogenic substances. This may pose a risk to benthic and epibenthic organisms and it is crucial that toxicity tests that are available for environmental risk assessment can identify potentially adverse effects of sediment-associated substances on benthic organisms, such as harpacticoid copepods. While marine harpacticoids have been protected via a number of acute and chronic sediment tests, the freshwater harpacticoid copepod community has so far been neglected in such activities. The main aim of the present study was therefore to (a) find a suitable freshwater harpacticoid copepod, (b) establish robust laboratory mass cultures and (c) develop a chronic test for assessment of sediment-associated toxicity using spiked sediments. After several cultivation trials with a number of potential test species, the choice fell on the benthic freshwater harpacticoid copepod Attheyella crassa, a species that possesses many of the characteristic features identified as prerequisites for toxicity test organisms, e.g. it has a sexual reproduction, it is relatively easy to grow and keep in mass cultures in the laboratory, and it has a small body size. Owing to the relatively long generation time of freshwater harpacticoids (in relation to many marine harpacticoids), it was decided that the test should be separated into a development part (21 days) and a reproduction part (14 days) running in parallel. As a reference substance we used the fungicide tebuconazole, which is currently subject to risk assessment and which partitions to soil and sediment. Clear concentration-related responses were observed for all endpoints analyzed. Nauplia body length was the most sensitive endpoint with a measured time weighted LOEC(water) of 20microg/L. The corresponding LOEC(water) for larval mortality and offspring production was 65 and 62microg/L, respectively. In conclusion, A. crassa is an ecologically relevant test species for freshwater ecosystems and particularly for the cold, oligotrophic and often acidic lakes of Northern Europe. Regardless of the relatively long generation time of this species, our results clearly show that sediment-associated toxicity related to development and sexual reproduction can be assessed within 2-3 weeks exposure with the developed bioassay.

  • 26. Ulhaq, Mazhar
    et al.
    Sundström, Maria
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Larsson, Pia
    Gabrielsson, Johan
    Bergman, Åke
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Norrgren, Leif
    Örn, Stefan
    Tissue uptake, distribution and elimination of C-14-PFOA in zebrafish (Danio rerio)2015In: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514, Vol. 163, p. 148-157Article in journal (Refereed)
    Abstract [en]

    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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