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- 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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- 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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| 6. |
- 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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| 8. |
- 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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