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Quantifying the precision of ecological risk: Conventional assessment factor method vs. species sensitivity
1National Institute for Advanced Industrial Science and Technology, Research Institute of Science for Safety and Sustainability, 16-1 Onogawa, Tsukuba, Ibaraki 305-8569, Japan.
Ecotoxicology and Environmental Safety
|August 4, 2019
Summary
The choice between Assessment Factor (AF) and Species Sensitivity Distribution (SSD) methods for ecological risk assessment depends on data. Larger sample sizes improve both methods, while low species sensitivity variation favors the AF approach.
Area of Science:
- Environmental Toxicology
- Ecotoxicology
- Risk Assessment
Background:
- Ecological risk assessment relies on Predicted No Effect Concentration (PNEC) derivation.
- Two primary methods exist: Assessment Factor (AF) and Species Sensitivity Distribution (SSD).
- The AF method uses a fixed factor, while SSD estimates a Hazardous Concentration for 5% of species (HC5).
Purpose of the Study:
- To compare the performance of AF and SSD methods in ecological risk assessment.
- To determine the most appropriate Assessment Factor (AF) values.
- To evaluate the effectiveness of each method under varying conditions.
Main Methods:
- Comparison of AF and SSD methods based on PNEC derivation.
- Performance evaluation using the criterion: more PNECs lower than HC5 indicates a better method.
- Analysis of the influence of sample size and species sensitivity variation.
Main Results:
- Both AF and SSD method performance improve with increased sample size (more toxicity data).
- The AF method performs better with low species sensitivity variation.
- AF method performance declines as species sensitivity variation increases.
Conclusions:
- Method performance is contingent on sample size and species sensitivity variation.
- Increased data availability enhances both AF and SSD methods.
- Understanding the drivers of species sensitivity variation is crucial for accurate ecological risk assessment.
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