Water quality objectives for mixtures of toxic chemicals: problems and perspectives

Vighi, Marco; Altenburger, Rolf; Arrhenius, Åsa; Backhaus, Thomas; Bödeker, Wolfgang; Blanck, Hans; Consolaro, F.; Faust, Martin L.; Finizio, Antonio; Froehner, K.; Gramatica, Paola; Grimme, L. Horst; Grönvall, Frederick; Hamer, V; Scholze, Martin; Walter, Helge

doi:10.1016/s0147-6513(02)00047-7

Cited by 88 publications

(42 citation statements)

References 22 publications

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“…Furthermore, ecosystem properties such as high biodiversity, species interactions, and ecological succession influence the impacts of stressors, and the ecological validity of single-species tests has been debated for decades because of their limitations in these respects [11,12]. This is obviously equally relevant in the context of mixture ecotoxicology, and hence, validation efforts of CA, under more ecologically realistic conditions than can be achieved in single-species tests, are clearly warranted, particularly for non-congeneric PSII inhibitors [13,14].…”

Section: Introductionmentioning

confidence: 99%

Mixture toxicity from photosystem II inhibitors on microalgal community succession is predictable by concentration addition

Porsbring

Backhaus

Johansson

et al. 2010

Enviro Toxic and Chemistry

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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.

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Section: Introductionmentioning

confidence: 99%

Mixture toxicity from photosystem II inhibitors on microalgal community succession is predictable by concentration addition

Porsbring

Backhaus

Johansson

et al. 2010

Enviro Toxic and Chemistry

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“…Whereas both models have been proved acceptable if the corresponding mechanistic assumptions are fulfilled, since exact modes of action are often unknown for many compounds, both CA and IA must be regarded as two special extreme cases [84,85] defining a frame where real values are contained. In practice, both models have been more or less successfully applied, being the results obtained with both of them not very different, with CA tending to overestimate and IA to underestimate toxicity in controlled experiments [86,87].…”

Section: Multichemical Risk Assessmentmentioning

confidence: 99%

Pollutants of Emerging Concern in Rivers of Catalonia: Occurrence, Fate, and Risk

Ginebreda

Pérez

Rivas

et al. 2015

The Handbook of Environmental Chemistry

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The present chapter provides a review of the occurrence, fate, and risk associated to different families or emerging and priority organic micropollutants in the rivers of Catalonia. Compounds belonging to diverse groups such as industrial compounds, perfluoroalkyl substances, pesticides, halogenated flame retardants, pharmaceuticals and hormones, personal care products, and illegal drugs, as well as their transformation products, are examined. Both emission levels from sewage systems and those found at the receiving water bodies are compared. Potential fate and transformation of the parent compounds is taken into consideration. Finally their environmental risk in terms of the associated ecotoxicity with respect to three trophic levels (Daphnia, algae, and fish) as recommended by the WFD is assessed. This prioritization exercise allows identifying those micropollutants that are more relevant in Catalonian Rivers.

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“…For example, most mixture experiments involve evaluation of at least 50 experimental units; thus, it often is not deemed feasible to run long-term studies. In addition, nearly all tests have been performed using single species and only a few studies have attempted to use CA models to predict toxic response at a community level (Vighi et al 2003;Arrhenius et al 2004). Further testing is needed to evaluate predictive models using chronic and multiple species designs.…”

Section: Size and Breadth Of Databasementioning

confidence: 99%

“…Thus, robust predictive models are needed that can estimate the toxicity of mixtures with acceptable accuracy (Vighi et al 2003;Lydy et al 2004). Furthermore, in order for mixture models to be useful in ecological risk assessments, knowledge of the uncertainty and potential bias of the models is necessary.…”

Section: Introductionmentioning

confidence: 99%

How well can we predict the toxicity of pesticide mixtures to aquatic life?

Belden

Gilliom

Lydy

2007

Integr Envir Assess & Manag

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Results of published pesticide mixture toxicity experiments conducted with aquatic organisms were compiled and evaluated to assess the accuracy of predictive mixture models. Three types of models were evaluated: Concentration addition (CA), independent action (IA), and simple interaction (SI). The CA model was the most often tested (207 experiments), followed by SI (59) and IA (37). The reviewed experiments are listed in the Supplemental material to provide a resource for future investigators. The predictive accuracy of each model was quantified for each experiment by the model deviation ratio (MDR), which was calculated by dividing the predicted toxicity by the observed toxicity. Eighty-eight percent of all experiments that evaluated the CA model had observed effective concentrations within a factor of 2 of predicted values (MDR values from 0.5-2.0). The median MDR was 1, about 5% of MDRs were less than 0.5, and about 5% were greater than 2, indicating unbiased estimates overall. The predictive accuracy of CA and IA models was influenced, however, by the different modes of action (MOA) of the pesticides. For experiments with pesticides with the same MOA, CA more accurately predicted effective concentrations for more experiments compared to IA, which tended to underpredict toxicity. The IA model was somewhat more accurate than the CA model for most mixtures with different MOAs, but in most cases there were relatively small differences between the models. Additionally, 80% of SI experiments had an MDR value below 2.0 despite a bias towards experiments that are likely to have an interaction. Thus, results indicate that the CA model may be used as a slightly conservative, but broadly applicable model with a relatively small likelihood of underestimating effects due to interactions.

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Water quality objectives for mixtures of toxic chemicals: problems and perspectives

Cited by 88 publications

References 22 publications

Mixture toxicity from photosystem II inhibitors on microalgal community succession is predictable by concentration addition

Mixture toxicity from photosystem II inhibitors on microalgal community succession is predictable by concentration addition

Pollutants of Emerging Concern in Rivers of Catalonia: Occurrence, Fate, and Risk

How well can we predict the toxicity of pesticide mixtures to aquatic life?

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