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- Arrhenius, Åsa, 1973, et al.
(author)
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Effects of three antifouling agents on algal communities and algal reproduction: Mixture toxicity studies with TBT, Irgarol, and Sea-Nine
- 2006
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In: Archives of Environmental Contamination and Toxicology. - : Springer Science and Business Media LLC. - 0090-4341 .- 1432-0703. ; 50:3, s. 335-345
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Journal article (peer-reviewed)abstract
- The toxicity of three antifoulants (Sea-Nine, Irgarol, and TBT) was determined individually and in mixtures in two tests with microalgae. Effects on periphyton community photosynthesis and reproduction of the unicellular green algae Scenedesmus vacuolatus were investigated. The tested antifoulants were highly toxic in both tests. Observed mixture toxicities were compared with predictions derived from two concepts: Independent Action (IA), assumed to be more relevant for the tested mixtures that were composed of dissimilarly acting substances, and Concentration Addition (CA), regarded as a reasonable worst-case approach in predictive mixture hazard assessment. Despite the corresponding mechanistic basis, IA failed to provide accurate predictions of the observed mixture toxicities. Results show the same pattern in both assays. Mixture effects at high concentrations were slightly overestimated and effects at low concentrations were slightly underestimated. Maximum observed deviations between observed and IA-predicted concentrations amount to a factor of 4. The suggested worst-case approach using CA was protective only in effect regions above 20%. Nevertheless, the application of any concept that accounts for possible mixture effects is more realistic than the present chemical-by-chemical assessment
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- Arrhenius, Åsa, 1973, et al.
(author)
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Marine Paint Optimisation: settling assays with marine periphyton communities and sea lettuce (Ulva lactuca)
- 2008
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In: The 14th International Congress on Marine Corrosion and Fouling, July 27-31, 2008, Kobe, Japan.
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Conference paper (other academic/artistic)abstract
- In the Marine Paint Optimisation project the major groups of fouling organisms will be studied. From each group of organisms one model organism was selected and used in settling assays to assess the efficacy of a number of individual antifoulants. A tentative list of existing and promising compounds include medetomidine, tolylfluanide, copper pyrithione, Sea-Nine, Irgarol, copper, Borocide, and Econea. Based on the produced data we will predict the joint effects of almost all possible combinations in terms of efficacy. The optimisation will be based both on high efficacy and low environmental risk. We will present and summarise the results from two settling assays with marine biofilms (microfouling) and the zoospores of the macroalga sea lettuce (Ulva lactuca). The microfoulers are important parts of the fouling community with a high number of different species and individuals which form the basis for all subsequent settlers. In this periphyton assay a multispecies microbial biofilm established in the field on Plexi glas (PMMA) are used to prepare an inoculum using a scrape, shake and sieve technique. Using this approach we include a large set of the potential species in the microbial fouling community. Ulva lactuca belongs to the most common family of fouling macroalgae. Thalli of Ulva lactuca were sampled in the field in September 2007, cultivated in the laboratory until further testing of the zoospores. Both assays are semistatic and run over three days and include both settling and growth. Efficacy data for a number of antifouling agents will be presented. This study is part of the Marine Paint research programme funded by MISTRA.
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- Arrhenius, Åsa, 1973, et al.
(author)
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Predictability of the mixture toxicity of 12 similarly acting congeneric inhibitors of photosystem II in marine periphyton and epipsammon communities
- 2004
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In: Aquatic Toxicology. - : Elsevier BV. - 0166-445X. ; 68:4, s. 351-367
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Journal article (peer-reviewed)abstract
- Testing of single chemicals with single species is common ecotoxicological practice in contrast to contaminated environments where highly diverse biological communities are exposed to highly diverse mixtures of chemical compounds. We, therefore, investigated whether mixture toxicity approaches that have been used successfully for single species, might also be applied on a community level of biological complexity. Twelve inhibitors of photosystem II, selected by QSAR and chemometrical approaches as the structurally most similar from a congeneric group of phenylurea herbicides, were tested singly and as mixtures on two types of marine microalgal communities, periphyton and epipsammon. Inhibition of photosynthesis was measured in short-term tests using incorporation of radiolabelled carbon (14C) to estimate photosynthetic rates. Two basic concepts, concentration addition (CA) and independent action (IA), were used to predict the toxicities of the mixtures. Congeneric and similar-acting substances such as the phenylureas are expected to comply with CA rather than IA. The aim of the present study was to evaluate whether these concepts can be used to predict mixture toxicity also to periphyton and epipsammon photosynthesis, i.e. at the level of natural communities. We found that deviations between observed and predicted mixture toxicity were relatively small but that CA predictions were the more accurate ones. The predictions proved to be robust, when based on single substance information even from different seasons, years, and sites. We conclude that the concept of CA for predicting mixture toxicity applies also at the community level of algal testing; at least when a physiological short-term effect indicator is used that matches the mechanism of action of the substances
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