Predicting the aquatic toxicity of commercial pesticide mixtures

Coors, Anja; Frische, Tobias

doi:10.1186/2190-4715-23-22

Cited by 43 publications

(32 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It would be less likely that frequent interactions would result in a uniform distribution, especially because lower MDR values were typically noted in studies where toxicity tests were conducted within a single method design instead of across laboratories (Belden et al 2007a). Previous analysis conducted similarly on a larger set of commercial formulas (n ¼ 274) reported a median MDR of 1, also suggesting no systematic bias toward synergy (Coors and Frische 2011). Ideally, all studies for individuals and mixtures would have definitive effective concentrations in order to most accurately calculate MDR values.…”

Section: Case Studies Using Pesticide Mixturesmentioning

confidence: 98%

“…Thus, experimental variability for mixture studies within the context of ERAs will likely be higher than that found in a single randomized test design common for mixture toxicity testing in literature. For example, Coors and Frische (2011) evaluated the predictability of mixture toxicity by CA of commercially sold pesticide products for which heterogeneity of the input data was likely high. Deviation from the CA model (higher percentage of MDR values >2) was found to be higher than reported in previous review papers focused on peerreviewed literature (Belden et al 2007a;Cedergreen 2014).…”

Section: Deviation From Mixture Modelsmentioning

confidence: 99%

“…Thus, all mixtures as reviewed by Belden et al (2007a) and Cedergreen (2014) that exceeded an MDR of 5 would be empirically tested on the basis of this recommendation. Other pesticides and classes may also be identified; for example, Coors and Frische (2011) linked iodosulfuron to synergy in aquatic invertebrates and fish. Second, other a priori knowledge about the toxicity of the formulative mixture may suggest testing is necessary.…”

Section: Formulative Mixtures Of Greater Concernmentioning

confidence: 99%

“…However, they typically do not evaluate the impact of formulation ingredients other than active ingredients. The analysis conducted by Coors and Frische (2011) was based on testing of formulations and comparing to active ingredients. The elevated number of mixtures that had MDR values of greater than 5 could result from either increased toxicity due to contribution of components of the formulation not considered active ingredients or higher than expected variability during toxicity testing.…”

Section: Establishing Mdr Limit Based On Variabilitymentioning

confidence: 99%

See 3 more Smart Citations

Incorporating the joint toxicity of co‐applied pesticides into the ecological risk assessment process

Belden

Brain

2017

Integr Envir Assess & Manag

View full text Add to dashboard Cite

Pesticides are frequently formulated as mixtures of active ingredients. Although traditionally ecological risk assessments (ERAs) have focused on individual active ingredients, there is an ongoing effort in many jurisdictions to more formally include assessment of mixtures. The overall goal of this project was to describe an approach for conducting ERA of jointly applied pesticides. We suggest that standard testing of formulation mixtures is not warranted due to the low probability of synergy occurring at a high-enough magnitude to be measurable above experimental variability. Thus, empirical testing should focus on formulations for which there is a greater likelihood of synergy due to known toxicological interactions of the pesticide class or a priori knowledge of synergy, such as intellectual property claims. Additionally, empirical testing should focus on species that are above levels of concern and limit testing on species for which it is unlikely that synergy would significantly change the outcome of the ERA. If empirical testing is warranted, we suggest that results be compared to the concentration addition model (CA). If the empirical data deviates from the model by a factor of greater than 5, then synergy is considered likely and the ERA is based on the empirical data. Otherwise, the ERA may use CA to calculate risk quotients or be based on the most toxic active ingredient. To evaluate the approach, we reviewed formulation mixtures for which data were available. Only 3 of 24 mixture studies were found to deviate from CA by more than 5. The majority of the studies had a single component that dominated toxicity, suggesting that the ERA for these formulations will not be meaningfully different if based on the most toxic active ingredient. Overall, this approach balances risk assessment conservatism and reduces testing that would likely not result in improvement of the ERA. Integr Environ Assess Manag 2018;14:79-91. C 2017 SETAC

show abstract

Section: Case Studies Using Pesticide Mixturesmentioning

confidence: 98%

Section: Deviation From Mixture Modelsmentioning

confidence: 99%

Section: Formulative Mixtures Of Greater Concernmentioning

confidence: 99%

Section: Establishing Mdr Limit Based On Variabilitymentioning

confidence: 99%

See 2 more Smart Citations

Incorporating the joint toxicity of co‐applied pesticides into the ecological risk assessment process

Belden

Brain

2017

Integr Envir Assess & Manag

View full text Add to dashboard Cite

show abstract

“…The general notion is that especially CA provides a quite reliable tool for predicting and assessing the joint ecotoxicity of chemicals, which has been quantitatively analyzed in a range of meta-reviews, often focusing on pesticides and pesticide products [6,23,24].…”

Section: Component-based Approachesmentioning

confidence: 99%

Proposal for environmental mixture risk assessment in the context of the biocidal product authorization in the EU

et al. 2013

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Mixture toxicity of wood preservative products in the fish embryo toxicity test

Coors

Dobrick

Möder

et al. 2012

Enviro Toxic and Chemistry

Self Cite

View full text Add to dashboard Cite

Wood preservative products are used globally to protect wood from fungal decay and insects. We investigated the aquatic toxicity of five commercial wood preservative products, the biocidal active substances and some formulation additives contained therein, as well as six generic binary mixtures of the active substances in the fish embryo toxicity test (FET). Median lethal concentrations (LC50) of the single substances, the mixtures, and the products were estimated from concentration-response curves and corrected for concentrations measured in the test medium. The comparison of the experimentally observed mixture toxicity with the toxicity predicted by the concept of concentration addition (CA) showed less than twofold deviation for all binary mixtures of the active substances and for three of the biocidal products. A more than 60-fold underestimation of the toxicity of the fourth product by the CA prediction was detected and could be explained fully by the toxicity of one formulation additive, which had been labeled as a hazardous substance. The reason for the 4.6-fold underestimation of toxicity of the fifth product could not be explained unambiguously. Overall, the FET was found to be a suitable screening tool to verify whether the toxicity of formulated wood preservatives can reliably be predicted by CA. Applied as a quick and simple nonanimal screening test, the FET may support approaches of applying component-based mixture toxicity predictions within the environmental risk assessment of biocidal products, which is required according to European regulations.

show abstract

Predicting the aquatic toxicity of commercial pesticide mixtures

Cited by 43 publications

References 32 publications

Incorporating the joint toxicity of co‐applied pesticides into the ecological risk assessment process

Incorporating the joint toxicity of co‐applied pesticides into the ecological risk assessment process

Proposal for environmental mixture risk assessment in the context of the biocidal product authorization in the EU

Mixture toxicity of wood preservative products in the fish embryo toxicity test

Contact Info

Product

Resources

About