15052 IUPAC Gold Book - species sensitivity distribution 10.1351/goldbook.15052 15052 current initialism: SSD 1 Statistical relationship between exposure concentration and a defined effect derived from a combination of single-species test data to predict concentrations affecting only a certain percentage of the total number of species in a defined community. Single-species data [e.g., median lethal concentration (\(\pu{LC_{50}}\)) or no-observed-effect concentration (NOEC) values] for many species are fitted to a distribution relationship such as the log-normal or log-logistic curve. From this distribution of species sensitivities, a hazardous concentration (\(\pu{HC_{\textit{p}}}\)) is identified at which a certain percentage (\(p\)) of all species is likely to be affected. The most conservative form of this approach uses the lower \(\pu{95\%}\) tolerance limit of the estimated percentage to ensure that the specified level of protection is achieved community https://goldbook.iupac.org//terms/view/14531 hazardous concentration https://goldbook.iupac.org//terms/view/14738 no-observed-effect concentration https://goldbook.iupac.org//terms/view/14885 PAC, 2009, 81, 829. 'Glossary of terms used in ecotoxicology (IUPAC Recommendations 2009)' on page 948 (https://doi.org/10.1351/PAC-REC-08-07-09) https://goldbook.iupac.org/terms/view/15052/html https://goldbook.iupac.org/terms/view/15052/json https://goldbook.iupac.org/terms/view/15052/plain Citation: 'species sensitivity distribution' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.15052 The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) for individual terms. If you are interested in licensing the Gold Book for commercial use, please contact the IUPAC Executive Director at executivedirector@iupac.org . The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using. 2026-04-21T12:21:15+00:00