Advancing Research on Understanding Environmental Effects of UV Filters from Sunscreens Proceedings of a Workshop (2023) / Chapter Skim
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Standardizing Approaches for Toxicity Testing
Standardizing Approaches for Toxicity Testing
Pages 14-26
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From page 14... ...
It is also critical, she pointed out, to ensure consistency in terms of water temperature, active ingredient level, salinity, pH level, analytical methodologies, and endpoints in order to generate data that will be comparable across species and laboratories and usable for ERAs. Standardized test methods are different for chronic and acute testing, but in either case, she said it is important to avoid open-ended toxicity values and establish species sensitivity distributions as a quantitative metric for understanding effects.
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From page 15... ...
In addition to long-established toxicity testing methods, Raimondo said that new approach methodologies can help to obtain reproducible, defensible, and environmentally and ecologically relevant endpoints for UV filter toxicity testing. The most important element of any testing approach, she continued, is to have a consistent, transferable test design with quantitative endpoints that show how organisms respond to a stressor, which can then be used to create higher-tier assessments that improve environmental realism and lead to ecologically relevant conclusions.
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From page 16... ...
Typically, the assumed concentration of UV filters in the water column is measured after a UV filter is added to the water vessel. However, Downs said it is important to recognize that some UV filters move out of the water column to the meniscus layer, vessel walls, or organisms' structural supports and could also be significantly affected by volatilization, all of which can lead to inaccurate measurements of the actual concentration.1 To combat this problem, he suggested using Teflon liners for beakers and conducting vigorous prescreening tests before introducing an organism in order to understand what confounding leachates may be present in exposure media.
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From page 17... ...
levels must be derived, typically using standard laboratory organisms. Until standardized toxicity tests are available, these PNEC levels can be used as surrogates to protect coral, freshwater sediment, and all nonstandard organisms.5, 6 5 Pawlowski, S., Moeller, M., Miller, I
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From page 18... ...
Chronic toxicity tests for coral fragments are in progress, and the team next plans to focus on coral bioaccumulation tests, with the goal of developing a standardized coral toxicity testing method that generates high-quality data in the next 5–10 years, Pawlowski said. Applied Development of Standardized Coral Toxicity Tests Abigail Renegar (Nova Southeastern University)
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From page 19... ...
To continue to refine and standardize testing approaches, Renegar said that it will be vital to overcome the challenges of analytical chemistry and balance testing standards and consistency with existing regulatory guidelines and metrics that are scalable for environmentally relevant exposures. Atlantic staghorn coral (Acropora cervicornis)
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From page 20... ...
Leonard also underscored that new test methodologies for coral should be biologically relevant to the taxonomically diverse assemblages of organisms that comprise coral reefs and stressed the importance of using species sensitivity distributions to identify and test the most sensitive species. Resource managers with the U.S.
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From page 21... ...
These methods can be adapted from existing EPA and OECD standards and guidelines, with modifications for nonstandard species and adequate quality assurance/quality control in order to enable reporting of reliable, relevant data for ERAs. Mitchelmore moderated an open discussion between panelists and workshop attendees that further explored toxicity testing challenges, the role of new approach methodologies and species sensitivity distributions, the importance of creating standards, and considerations specific to working with corals and mussels.
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From page 22... ...
New Approach Methodologies and Species Sensitivity Distributions Once relevant, reliable data have been generated, next steps for UV filters can be determined, but Davies noted that this process will take time. To speed progress, problem formulation is an important consideration.
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From page 23... ...
Creating Standards To work toward standardization in toxicity testing for UV filters, Raimondo stated that EPA is focused on reducing sources of variability or uncertainty in terms of factors like pH level, light, salinity, test chambers, water quality, and temperature, all of which can affect analyses. Mitchelmore agreed that water quality standards should include baseline exposure media to keep water quality stable.
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From page 24... ...
The challenges of identifying nonstandard species to target, reliably accessing those organisms, and resolving practical considerations for culturing them in a laboratory are not trivial. For many nonstandard species, the lack of a baseline understanding of behavior, genotype, characteristics, life cycles, and sensitivity hampers the ability to design culture conditions that mimic the natural environment and conduct toxicity tests that are appropriate and relevant.
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From page 25... ...
For this, it would likely be helpful to identify areas where exposure is highest, discover other exposure pathways beyond sunscreens, and generate robust, statistical endpoint data that would be useful in EPA ERAs. In terms of specific suggestions for future research, some participants mentioned investing in more studies of benthic organisms, sediment, and freshwater species; refining methods to culture nonstandard organisms for laboratory testing; studying multiple stressors separately; and working to further enhance, validate, and increase the use of new approach methodologies.
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From page 26... ...
Some participants suggested broadening ERAs to incorporate a wider range of evidence types and many participants reiterated the desire to find the right exposure media; identify the most important variables; use mesocosms to enable dose dependent responses, transportation, and location in the water column; use field exposures to give environmental context to laboratory tests; estimate biological responses for nonstandard organisms via modeling and nonstandard metrics for sublethal effects; and ask experts to translate toxicology work into real-world scenarios. From a broader perspective, some participants mentioned the usefulness of deep reflection on industry responsibility and ethics, a better understanding of consumer behavior, a holistic approach to ecosystem stability, an acknowledgment that animals should not be sacrificed unnecessarily, and a push for more open science practices.
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