Applying species-sensitivity distributions in ecological risk assessment: Assumptions of distribution type and sufficient numbers of species

Autor: Tyler R. L. Christensen, Britt-Anne Anderson, Laurent C. Mézin, Michael C. Newman, Scott Lerberg, David R. Ownby, David C. Powell
Rok vydání: 2000
Předmět:
Zdroj: Environmental Toxicology and Chemistry. 19:508-515
ISSN: 1552-8618
0730-7268
DOI: 10.1002/etc.5620190233
Popis: Species-sensitivity distribution methods assemble single-species toxicity data to predict hazardous concentrations (HCps) affecting a certain percentage (p) of species in a community. The fit of the lognormal model and required number of individual species values were evaluated with 30 published data sets. The increasingly common assumption that a lognormal model best fits these data was not supported. Fifteen data sets failed a formal test of conformity to a lognormal distribution; other distributions often provided better fit to the data than the lognormal distribution. An alternate bootstrap method provided accurate estimates of HCp without the assumption of a specific distribution. Approximate sample sizes producing HC5 estimates with minimal variance ranged from 15 to 55, and had a median of 30 species-sensitivity values. These sample sizes are higher than those suggested in recent regulatory documents. A bootstrap method is recommended that predicts with 95% confidence the concentration affecting 5% or fewer species.
Databáze: OpenAIRE
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