| 1. |
- Backhaus, Thomas, 1967, et al.
(författare)
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Proposal for environmental mixture risk assessment in the context of the biocidal product authorization in the EU
- 2013
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Ingår i: Environmental Sciences Europe. - : Springer Science and Business Media LLC. - 2190-4715 .- 2190-4707. ; 25
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Background: The EU Council and Parliament recently agreed on a new regulation that will implement a new EU-wide, harmonized system for the authorization for biocidal products. Such products are in most cases multi-component mixtures of one or more active substances plus a range of co-formulants that serve different purposes, e.g. as stabilizers or preservatives. They are only allowed on the European market if their intended use does not lead to unacceptable risks for the environment. Consequently, the assessment of possible combination effects is a critically important step during the regulatory environmental risk assessment of biocidal products. However, no specific guidance is at hand on how combination effects should be accounted for during the regulatory environmental risk assessment of biocidal products. Results and Conclusions: A tiered approach was developed that accommodates different data situations, optimizes resource usage, limits biotesting as far as possible and ensures adequate protection of the environment. It mainly builds on using Concentration Addition as a component-based approach for mixture toxicity prediction, complemented by whole product tests where appropriate. Concentration Addition is either approximated by summing up PEC/PNEC ratios or as sums of toxic units. The competing concept of Independent Action was assessed as not being suitable for incorporation into a tiered approach without explicit confirmatory studies, as it might otherwise lead to an underestimation of the actual environmental risk.
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| 2. |
- Porsbring, Tobias, 1974, et al.
(författare)
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The pharmaceutical clotrimazole affects marine microalgal communities at picomolar concentrations
- 2009
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Ingår i: SETAC Europe 19th Annual Meeting, Gothenburg, Sweden.
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Konferensbidrag (refereegranskat)abstract
- Clotrimazole is a pharmaceutical that belongs to the group of 14alpha-demethylase inhibiting fungicides. It is widely used and has been identified as a priority pollutant for the marine environment. However, the toxicity of clotrimazole to marine primary producers is largely unknown. We therefore sampled natural microalgal communities (periphyton) and exposed them to concentration series of clotrimazole over 4 days. Already 50 pmol/L clotrimazole caused a concentration-dependent accumulation of C14alpha-methylated sterol precursors, which coincided with a decrease in normal C14-desmethyl sterols. This indicates an inhibition of algal 14alpha-demethylases already at environmental concentrations. A clotrimazole concentration of 500 pmol/L reduced total sterol content to 64% of control level. Clotrimazole concentrations in the picomolar range also reduced biomass of the microalgal community, and interfered with the diatom xantophyll cycling otherwise used for photoadaptation. Concentrations of 10 nmol/L and higher caused large reductions in community growth, and changed community pigment profiles. As clotrimazole concentrations in the marine environment can reach 100 pmol/L, an environmental risk for marine primary producers cannot be excluded.
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| 3. |
- Porsbring, Tobias, 1974, et al.
(författare)
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Toxicity of the pharmaceutical clotrimazole to marine microalgal communities
- 2009
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Ingår i: Aquatic Toxicology. - : Elsevier BV. - 0166-445X. ; 91, s. 203-211
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Tidskriftsartikel (refereegranskat)abstract
- Clotrimazole belongs to the group of 14α-demethylase inhibiting fungicides. It is widely used in human and veterinary medicine and has been identified as a priority pollutant for the marine environment. However, the toxicity of clotrimazole to marine primary producers is largely unknown. We therefore sampled natural microalgal communities (periphyton) and exposed them to concentration series of clotrimazole over 4 days. 50 pmol/L clotrimazole caused a concentration-dependent accumulation of C14α-methylated sterol precursors, which coincided with a decrease in algal-specific C14-desmethyl sterols. This indicates an inhibition of algal 14α-demethylases already at environmental concentrations. A clotrimazole concentration of 500 pmol/L reduced total sterol content to 64% of control level. Community chlorophyll a content was affected by clotrimazole in a bi-phasic manner with first reductions becoming visible at 500 pmol/L, along with indications of an altered cycling of photoprotective xanthophyll pigments. Concentrations of 10–100 nmol/L and higher caused large reductions in community growth, and changed community pigment profiles in a concentration-dependent monotonous manner. The study further indicated that diatoms use obtusifoliol as a natural substrate for 14α-demethylase, just as higher plants do but also utilize norlanosterol.
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| 4. |
- Arrhenius, Åsa, 1973, et al.
(författare)
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Toxicity of the fungicide ketoconazole to freshwater microalgal communities
- 2015
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Ingår i: SETAC Europe 25th Annual Meeting, Barcelona Spain.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Antimycotic pharmaceuticals are widely used for treating fungal infections in humans and animals. They enter the aquatic environment either after passage through the body, or after being rinsed off if they are topically applied. However, substantial knowledge gaps currently hamper a proper environmental risk assessment of the individual antimycotics and their mixtures for marine and freshwater environments. Clotrimazole, a marine priority pollutant, affected sterol composition of marine microalgal communities already at 50 pmol/L which indicates effects already at environmental concentrations. In the present study we focus on ketoconazole (also an azole fungicide) and toxicity to freshwater microalgal communities. A concentration response curve was first established using pigment profiles (HPLC) as endpoint which resulted in an EC50 of around 1 micromol/L. During autumn 2014 we repeated the study but focused on the lower concentration range from 0.0001 to 1 micromol/L. Results on chlorophyll a show similar patterns as in the initial study. The experiments were finished during autumn 2014 and are currently under final evaluation and sterol analysis, species determinations and analytical confirmation of exposure concentrations are currently evaluated. The work is performed within the Swedish Formas-funded project “Aquatic Environmental Risk Assessment of Antimycotics”.
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| 5. |
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| 6. |
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| 7. |
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| 8. |
- Backhaus, Thomas, 1967, et al.
(författare)
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SINGLE-SUBSTANCE AND MIXTURE TOXICITY OF FIVE PHARMACEUTICALS AND PERSONAL CARE PRODUCTS TO MARINE PERIPHYTON COMMUNITIES
- 2011
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Ingår i: Environmental Toxicology and Chemistry. - : Wiley. - 0730-7268. ; 30:9, s. 2030-2040
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Tidskriftsartikel (refereegranskat)abstract
- The single-substance and mixture toxicity of five pharmaceuticals and personal care products (fluoxetine, propranolol, triclosan, zinc-pyrithione, and clotrimazole) to marine microalgal communities (periphyton) was investigated. All compounds proved to be toxic, with median effective concentration values (EC50s) between 1,800 nmol/L (triclosan) and 7.2 nmol/L (Zn-pyrithione). With an EC50 of 356 nmol/L, the toxicity of the mixture falls into this span, indicating the absence of strong synergisms or antagonisms. In fact, a comparison with mixture toxicity predictions by the classical mixture concepts of concentration addition and independent action showed a good predictability in the upper effect range. However, the mixture provoked stimulating effects (hormesis) in the lower effect range, hampering the application of either concept. An independent repetition of the mixture experiment resulted in a principally similar concentration-response curve, again with clear hormesis effects in the lower range of test concentrations. However, the curve was shifted toward higher effect concentrations (EC50 1,070 nmol/L), which likely is due to changes in the initial species composition. Clear mixture effects were observed even when all five components were present only at their individual no-observed-effect concentrations (NOECs). These results show that, even with respect to mixtures of chemically and functionally dissimilar compounds, such as the five pharmaceuticals and personal care products investigated, environmental quality standards must take possible mixture effects from low-effect concentrations of individual compounds into consideration. Environ. Toxicol. Chem. 2011;30:2030-2040. (C) 2011 SETAC
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| 9. |
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| 10. |
- Johansson, Henrik, 1984, et al.
(författare)
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Chronic toxicity of human pharmaceuticals to bacterial communities: evaluation of the mixture toxicity of sulfamethoxazole and trimethoprim.
- 2009
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Ingår i: SETAC Europe 19th Annual meeting, 31 May - 4 June, 2009, Göteborg..
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Human pharmaceuticals are mainly emitted into the aquatic environment after use and some occur in detectable levels in aquatic ecosystems. Trimethoprim and sulfamethoxazole, two antibiotics both acting on folic acid synthesis but at different stages, have been found to co-occur. They are also administered in combination when treating urinary tract infections due to their synergistic effects. The aim of the study was to determine if a binary mixture of sulfamethoxazole and trimethoprim exert any synergistic effect on natural bacterial communities, or if the effects were predictable using Independent Action (IA). Glass discs (1,5 cm2) were submerged in the stream of Mölndalsån (20 km East of Gothenburg), on which natural periphyton communities (attached bacterial, microalgal and cyanobacterial communities) were colonised. The periphyton communities were taken into the lab after seven days of colonisation and were exposed to the toxicants in a semi static test for 72 hours. Two different background concentrations of trimethoprim (50nm, 5000nM) were combined with six different concentrations of sulfamethoxazole (16nM – 5000nM). Effects on the periphytic bacteria were measured as changes in metabolic diversity with the so called Biolog Ecoplates®, i.e. changes in the ability of the bacterial communities to utilise 31 different carbon sources. This served as a measure of toxicant-induced effects on bacterial community biomass and taxonomic composition. The combination effects were predictable by IA and no synergistic effects were noticed.
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| 11. |
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| 12. |
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| 13. |
- Porsbring, Tobias, 1974, et al.
(författare)
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Effects of clotrimazole on the pigment composition of marine periphyton communities for use in predictive ecological mixture toxicity assessment
- 2006
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Ingår i: SETAC Europe 16th Annual Meeting, The Hague, The Netherlands.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Clotrimazole is a pharmaceutic fungicide classified as persistent and toxic according to EU Technical Guidance Document, and reaches the marine environment mainly from municipal waste water treatment plants together with several other pollutants. In a project to assess mixture toxicity of pharmaceuticals on microbial communities, clotrimazole effects on the development of periphyton were measured in two independent SWIFT tests in 2004 and 2005. Microalgal communities were precolonised in the Gullmar fjord on the west coast of Sweden on 1.5 cm2 glass discs. Following a 96h incubation in a concentration series of clotrimazole, periphyton pigment profiles were analysed using HPLC, and effects were calculated as Bray-Curtis dissimilarity indices. In both tests, a clotrimazole concentration of 11 microg/l had a significant effect on pigment composition with a NOEC of 3.45 microg/l (nominal). This indicates an approximately 5 times higher clotrimazole toxicity to algae than single species data, although comparisons to PEC values suggests a low risk for marine algae. However, the importance of clotrimazole for the risks of mixtures is further researched.
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| 14. |
- Porsbring, Tobias, 1974, et al.
(författare)
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Effects of PSII inhibitors on the succession of natural marine microalgal communities is predictable by Concentration Addition
- 2009
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Ingår i: SETAC Europe 19th Annual Meeting, Gothenburg, Sweden.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Aquatic ecosystems are always exposed to chemical mixtures, and it is not sufficient to assess the risks of single chemicals one at a time. Concentration Addition (CA) has received much attention as a predictive tool to assess mixture toxicity. The accuracy of the concept for mixtures of similarly acting chemicals has been extensively demonstrated under relatively simple biological conditions with single species tests. Because ecosystems contain a high diversity of inter-connected species it is necessary to evaluate CA also on at least a community level of biological organisation. We sampled natural marine periphyton communities (attached microalgal and cyanobacterial communities) on glass discs submerged on the West coast of Sweden, and exposed them to toxicants over a 4 days ecological succession in the SWIFT periphyton test. The test medium consisted of filtered (GF/F) seawater with added PO42- and NO3- (0.7 and 8 micromol/L respectively) and was renewed daily. Multi- Dimensional Scaling was used to assess similarity in ecological mode of action between 2 different reference sets of PSII (photosystem II) inhibitors, on community species composition and pigment profiles. One mixture comprised phenylureas a priori determined as sharing a high similarity in mode of action. The other mixture comprised non-congeneric inhibitors of PSII (a phenylurea, an s-triazin and a uracil). The PSII inhibitors caused similar changes in species composition and pigment profiles, demonstrating that they shared a high similarity in ecological mode of action. CA accurately predicted the effects of both mixtures on pigment profiles. This demonstrates that CA has a high relevance on a community level, and is a justified approach to predict the joint risk from co-occurring inhibitors of PSII.
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| 15. |
- Porsbring, Tobias, 1974, et al.
(författare)
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Mixture toxicity from PSII inhibitors on microalgal community succession is predictable by Concentration Addition
- 2010
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Ingår i: Environmental Toxicology and Chemistry. - : Wiley. - 0730-7268. ; 29:12, s. 2806-2813
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Tidskriftsartikel (refereegranskat)abstract
- The typical pollution situation Involves chemical mixtures and assessing the risks of single chemicals one at a time is not sufficient Concentration addition (CA) has been suggested as a predictive tool in mixture ecotoxicology The accuracy of CA for mixtures of similarly acting chemicals has been demonstrated under relatively simple biological conditions in single species tests To consider the high diversity of interconnected species in ecosystems one must evaluate CA on a community level of biological organization We sampled marine periphyton communities from the west coast of Sweden and exposed them to photosystem II (PSII) inhibiting herbicides for 4 d in the SWIFT test a semistatic small-scale laboratory test During this time the communities went through an ecological succession influenced by the toxicants in a concentration dependent manner Multidimensional scaling was used to assess similarities in the effects of two different sets of PSII inhibitors on pigment profiles which reflects the taxonomic structure and the physiological status of the microalgal community One mixture of structurally congeneric phenylureas and one mixture of non congeneric PSII inhibitors were tested All PSII inhibitors and their mixtures caused similar changes in the pigment profiles demonstrating that they not only have a similar biochemical mechanism of action but also are similarly acting on a community level Concentration addition accurately predicted the effects of both mixtures over the entire effect range This demonstrates that chemical congenericity is not required for a high predictive power of CA Instead in perfect analogy to the situation in single species tests a similar mode of action is a sufficient prerequisite for a successful application of CA Environ Toxicol Chem 2010 29 2806-2813 (C) 2010 SETAC
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| 16. |
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| 17. |
- Porsbring, Tobias, 1974, et al.
(författare)
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Observed and predicted combination effects of the antifouling agents irgarol 1051, TBT and Sea-Nine TM 211 on the structural and functional properties of marine microalgal communities
- 2004
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Ingår i: SETAC Europe 14th Annual meeting, Prague, Czech Republic.
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Konferensbidrag (refereegranskat)abstract
- Risks of mixtures of pollutants in ecosystems cannot be assessed when chemicals are treated as acting alone. This issue is increasingly recognised, but valid and useful tools for considering mixtures are needed. However the concepts Concentration Addition (CA) and Independent Action (IA) has been shown to have potential for predicting mixture toxicities. With the aim to evaluate CA and IA under ecologically realistic conditions the antifouling agents irgarol 1051, Sea-NineTM211 and TBT were tested singly and in an equieffective mixture on marine periphyton communities in a semistatic SWIFT test. Periphyton was established on 1.5 cm2 glass discs submerged in the Gullmar fjord, Sweden and then incubated for 96 h under constant light and temperature in a medium of GF/F filtered seawater with added phosphate, nitrate and toxicant(s). Effects were then quantified by comparing analysed pigment and species composition between treatments and controls using Bray-Curtis dissimilarity index. The observed mixture effect on species composition was in perfect agreement with CA, while IA was accurate for lower observed effects but overestimated the toxicity at higher. Using pigments for predictions was found to be sensitive as this reflected lower observed effects on species composition. IA and CA are beleived to apply for mixtures of toxicants with dissimilar and similar biochemical mechanisms of action respectively and as irgarol, TBT and Sea-Nine are dissimilarly acting the most accurate prediction should be IA. However biochemical modes of action may become less relevant for predictions in an ecological context where a mode of action could be defined more by impacts on specific species and trophic levels. Results indicates that risks of mixtures should be considered and are predictable.
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| 18. |
- Porsbring, Tobias, 1974
(författare)
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On Toxicant-Induced Succession in Periphyton Communities: Effects of Single Chemicals and Chemical Mixtures
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis deals with the effects of single chemicals and chemical mixtures on biological communities. Ecosystems are exposed to complex mixtures of chemicals, and because combination effects can occ... merur, it is necessary to assess the joint environmental risk from co-occurring contaminants. Two concepts are available to predict joint toxicity if the concentrations and toxicities of the single chemicals are known. Concentration Addition (CA) is believed to apply for mixtures of similarly acting chemicals, whereas the opposite concept of Independent Action (IA) was developed for dissimilarly acting chemicals. Most validation efforts of CA and IA have been performed under relatively simple biological conditions using single species tests. However, because the aim is to predict the risks of mixtures to complex and variable systems in nature, it is necessary to test the applicability of CA and IA on at least a community-level of biological complexity. Natural communities contain a tremendous biological diversity and thus a multitude of potential targets susceptible to toxicant exposure. In addition, species interact and a reduced ecological fitness of one species can thereby indirectly affect other species. This has the consequence that similarly acting chemicals on a biochemical/physiological level might be dissimilarly acting in a multispecies community, and ecological interactions alone are out of scope of both CA and IA. Natural marine periphyton communities were sampled from the environment on artificial substrata and incubated over a period of ecological succession together with single chemicals and chemical mixtures. Patterns and magnitude of toxicant-induced succession in the microalgal and cyanobacterial component of the biofilm were assessed by species counts using microscopy and/or chemotaxonomic analysis of pigment profiles. The resulting toxicant-induced changes were then used to assess similarity or dissimilarity between the chemicals in their ecological mode of action, and the precision with which CA and IA could predict effects from reference mixtures of similarly and dissimilarly acting chemicals. On a biochemical level similarly acting photosystem II-inhibiting herbicides acted similarly also in the periphyton communities, and CA provided an accurate prediction for their joint toxicity. CA was equally powerful for a mixture of non-congeneric PSII inhibitors assumed beforehand to have a less similar ecological mode of action. IA was slightly better than CA for predicting the joint effect from a mixture of dissimilarly acting pharmaceuticals and personal-care products. At a mixture concentration that caused a 50% reduction in biomass, IA deviated from the observed effect only by a factor of 1.1. However, lower concentrations of this mixture caused a stimulation of biomass, a phenomenon which is outside the scope of both CA and IA. The mixture studies further strengthens the evidence that joint toxicity needs to be considered in risk assessments even if the chemicals do not cause a discernible effect on their own. Furthermore, the findings show that both CA and IA are suitable to predict risks from co-occurring pollutants on community structure. The human pharmaceutical clotrimazole is regarded as a priority pollutant to the marine environment and its ecotoxicity was specifically evaluated. Clotrimazole is a fungicide that inhibits sterol synthesis at 14alpha-demethylase (14DM). Periphyton communities exposed to 50 pmol/L clotrimazole had a reduced 14DM functioning, and 500 pmol/L clotrimazole had profound effects on sterol biosynthesis which coincided with a decrease in biomass. Because up to 100 pmol/L clotrimazole has been detected in the marine environment, this indicates that the current use of clotrimazole is associated with a high environmental risk.
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| 19. |
- Porsbring, Tobias, 1974, et al.
(författare)
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The SWIFT periphyton test for high-capacity assessments of toxicant effects on microalgal community development
- 2007
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Ingår i: Journal of Experimental Marine Biology and Ecology. - : Elsevier BV. - 0022-0981. ; 349:2, s. 299-312
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Tidskriftsartikel (refereegranskat)abstract
- The SWIFT periphyton test was developed as a simple and high-capacity approach for assessing toxicant effects on the succession of natural communities. Attached microbial communities (periphyton) were developed over a 7 to 9 day period on artificial glass substratum submerged at sea and then transferred to a controlled indoor environment for 4 day incubation with toxicants. Added nutrients and continuous light over the test phase facilitated periphyton growth and consequently accelerated the rate of ecological succession. The structure and physiology of the algal community can be analysed using any suitable method. In this paper we suggest HPLC-based analyses of community pigment profiles as a fast and less laborious alternative to e.g. microscopic species counts. Several crucial properties of the SWIFT test were evaluated: the biological complexity of the periphyton used for testing, the consequences of the 4 day incubation under artificial conditions, toxicant effects on community structure and the feasibility of using pigment profiles as descriptors of periphyton communities. The performance of SWIFT as an ecotoxicological test system was evaluated using the three antifouling agents irgarol 105 1, Sea-Nine(TM) 211 (DCOIT) and TBT (tri-n-butyltin). Periphyton communities used in SWIFT were of high taxonomic richness and diversity, and there were no indications for adverse changes in these characteristics over the 4 day test phase. Community pigment profiles discriminated between different communities with a resolution equally good to microscopic species counts. Comparative concentration-response studies with a two-week microcosm experiment and SWIFT revealed similar concentration and toxicant-dependent shifts in the relative abundances of species. This shows that despite the methodological simplifications in SWIFT, crucial ecological features such as competition and species sensitivity profiles were still the major factors determining the ecological succession under toxicant exposure. The sensitivity of SWIFT was equal to that of the flow-through microcosms for irgarol and TBT and lower for DCOIT, probably because of the semi-static test regime in SWIFT. Species composition and pigment profiles over seasons, together with toxicant-induced effects on the diatom xantophyll cycle and the relative content of beta-carotene, shows that pigment profiles reflect both the taxonomy and the physiology of a community. Similar to encountered changes in species composition, pigment profiles were specifically influenced by the tested toxicants. (C) 2007 Elsevier B.V. All rights reserved.
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| 20. |
- Wernersson, Ann-Sofie, 1969, et al.
(författare)
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The European technical report on aquatic effect-based monitoring tools under the water framework directive
- 2015
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Ingår i: Environmental Sciences Europe. - : Springer Science and Business Media LLC. - 2190-4715 .- 2190-4707. ; 27:11 March 2015
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Tidskriftsartikel (refereegranskat)abstract
- The Water Framework Directive (WFD), 2000/60/EC, requires an integrated approach to the monitoring and assessment of the quality of surface water bodies. The chemical status assessment is based on compliance with legally binding Environmental Quality Standards (EQSs) for selected chemical pollutants (priority substances) of EU-wide concern. In the context of the mandate for the period 2010 to 2012 of the subgroup Chemical Monitoring and Emerging Pollutants (CMEP) under the Common Implementation Strategy (CIS) for the WFD, a specific task was established for the elaboration of a technical report on aquatic effect-based monitoring tools. The activity was chaired by Sweden and co-chaired by Italy and progressively involved several Member States and stakeholders in an EU-wide drafting group. The main aim of this technical report was to identify potential effect-based tools (e.g. biomarkers and bioassays) that could be used in the context of the different monitoring programmes (surveillance, operational and investigative) linking chemical and ecological status assessment. The present paper summarizes the major technical contents and findings of the report.
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