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Comparisons of PNEC derivation logic flows under example regulatory schemes and implications for ecoTTC
S E Belanger1, A Beasley2, J L Brill1
1The Procter & Gamble Company, Cincinnati, OH, USA.
Regulatory Toxicology and Pharmacology : RTP
|April 23, 2021
Summary
Environmental risk assessment uses Predicted No Effect Concentrations (PNECs) derived with application factors (AFs). Comparing methodologies revealed that chemical attributes and modes of action improve extrapolations, with algal data being crucial.
Area of Science:
- Environmental Chemistry
- Ecotoxicology
- Risk Assessment
Background:
- Predicted No Effect Concentrations (PNECs) are crucial for aquatic environmental risk assessment, derived using application factors (AFs) based on available ecotoxicity data.
- Regulatory jurisdictions differ in their application factor methodologies for deriving chemical-specific PNECs.
- The EnviroTox Platform provides a curated database and tools for consistent PNEC derivation.
Purpose of the Study:
- To compare PNEC derivation methodologies from different regulatory frameworks (US EPA and EU).
- To assess the impact of data availability (acute vs. chronic) on PNEC values.
- To investigate the influence of specific taxa, like algae, on PNEC estimations.
Main Methods:
- Applied two distinct PNEC derivation methodologies to a public ecotoxicity database (3647 compounds) using the EnviroTox Platform.
- Calculated ranked probability distributions and 5th percentile PNEC values for the entire dataset and specific data availability scenarios.
- Analyzed the influence of chemical attributes, modes of action, and algal data on PNEC values.
Main Results:
- Significant differences in estimated PNEC values were observed between the two methodologies.
- Full acute or chronic datasets resulted in measurably higher 5th percentile PNEC values compared to limited datasets.
- Algae, despite under-representation, disproportionately influenced PNEC values, highlighting their importance in hazard assessment.
- Categorization by chemical attributes and modes of action suggested improved extrapolation accuracy.
Conclusions:
- PNEC derivation methodologies significantly impact risk assessment outcomes.
- Comprehensive ecotoxicity datasets, including chronic and algal data, are essential for robust environmental hazard assessments.
- The EnviroTox Platform offers a transparent and consistent approach to PNEC derivation and distribution analysis, aiding regulatory science.
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