Ecotoxicology

, Volume 10, Issue 1, pp 25–34 | Cite as

Estimating the 5-Percentile of the Species Sensitivity Distributions Without Any Assumptions about the Distribution

  • Nelly Van der Hoeven

Abstract

A non-parametric method is described to estimate the hazardeous concentration for p% of the species, the HCp, and the confidence limits for this value, the HCp(α). For this method, all observed sensitivities are ordered from high to low sensitivity. The HC5 is the k-th observation were k is the largest integer below 0.05×(n+1). It is described how the HCp(α) can be calculated. A table is presented for easy calculation of several conservative confidence limits for the HC5. For the HC5(0.05), a second table is presented which can be used to interpolate between the conservative estimate of the HC5(0.05) and the next higher observed concentration. The non-parametric HC5 and HC5(0.05) estimation is illustrated with an example of sensitivity data on malathion. For this data set, the log-normal HC5 and HC5(0.05) estimations appear to be conservative compared with the non-parametric estimate. It is stressed that HC5 and HC5(0.05) estimates will often be much more affected by the non-randomness of the species set for which sensitivity data are available than by the choice of the statistical method.

beta distribution hazardous concentration 

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References

  1. Aldenberg, T. and Slob, W. (1993). Confidence limits for hazardous concentrations based on the logistically distributed NOEC toxicity data. Ecotoxicol. Enυiron. Saf. 25, 48–63.Google Scholar
  2. Jagoe, R.H. and Newman, M.C. (1997). Bootstrap estimation of community NOEC values. Ecotoxicology 6, 293–306.Google Scholar
  3. Kooijman, S.A.L.M. (1987). A safety factor for LC50 values allowing for differences in sensitivity among species. Water Res. 21, 269–76.Google Scholar
  4. Newman, M.C., Ownby, D.R., Mezin, L.C.A., Powell, D.C., Christensen, T.R.L., Lerberg, S.B. and Anderson, B.A. (2000). Applying species sensitivity distributions in ecological risk assessment: assumptions of distribution type and sufficient number of species. Enυiron. Toxicol. Chem. 19, 508–15.Google Scholar
  5. van Straalen, N.M. and Denneman, C.A. (1989). Ecotoxicological evaluation of soil quality criteria. Ecotoxicol. Enυiron. Saf. 18, 241–51.Google Scholar
  6. Wagner, C. and Løkke, H. (1991). Estimation of ecotoxicological protection levels for NOEC toxicity data. Water Res. 25, 1237–42.Google Scholar

Copyright information

© Kluwer Academic Publishers 2001

Authors and Affiliations

  • Nelly Van der Hoeven
    • 1
  1. 1.ECOSTATLeidenThe Netherlands

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