The No-Significant-Effect Concentration
An alternative toxicity estimate to the no-effect concentration (NEC) has been developed - the no-significant-effect concentration (NSEC). The no-effect concentration (NEC) is the preferred threshold metric for single-species toxicity tests applied to derive safe concentration thresholds for contaminants in the environment for use in species sensitivity distributions, but is only suitable when concentration–response (C-R) data exhibit a threshold response.
The no-significant-effect concentration (NSEC) is better suited to C-R data for which the response is a monotonically decreasing function of concentration and no threshold effects are evident. A flexible, three-parameter sigmoidal function is used to describe the C-R relationship and detail both Bayesian and frequentist approaches to estimation and inference for the NSEC.
Data and resources
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GitHub Repository link: NSECETandCHTML Open
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Fisher, R. and Fox, D.R. (2023), Introducing the No-Significant-Effect Concentration. Environ Toxicol Chem. https://doi.org/10.1002/etc.5610HTML Open
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Additional information
| Date (revision) | 2026-10-24 |
|---|---|
| Status | completed |
| Update frequency | asNeeded |
| Metadata language | en |
| License | Creative Commons Attribution 4.0 |
| Source metadata | ISO 19115 XML |
| Last updated | 2026-11-05 |
| Created | 2026-11-05 |
| API | package_show |