Species Sensitivity Distribution (SSD) for endosulfan
Summary of 48- to 96-hour acute toxicity values (LC50 and EC50 values) for exposure of Australian an Non-Australian taxa to endosulfan.
data(endosulfan)
endosulfan
is a data frame with 3 columns, named ATV for Acute Toxicity Value
(geometric mean of LC50 ou EC50 values in micrograms per liter),
Australian (coding for Australian or another origin) and group
(arthropods, fish or non-arthropod invertebrates).
Hose, G.C., Van den Brink, P.J. 2004. Confirming the Species-Sensitivity Distribution Concept for Endosulfan Using Laboratory, Mesocosms, and Field Data. Archives of Environmental Contamination and Toxicology, 47, 511-520.
# (1) load of data # data(endosulfan) # (2) plot and description of data for non Australian fish in decimal logarithm # log10ATV <-log10(subset(endosulfan,(Australian == "no") & (group == "Fish"))$ATV) plotdist(log10ATV) descdist(log10ATV,boot=1000) # (3) fit of a normal and a logistic distribution to data in log10 # (classical distributions used for SSD) # and visual comparison of the fits # fln <- fitdist(log10ATV,"norm") summary(fln) fll <- fitdist(log10ATV,"logis") summary(fll) cdfcomp(list(fln,fll),legendtext=c("normal","logistic"), xlab="log10ATV") denscomp(list(fln,fll),legendtext=c("normal","logistic"), xlab="log10ATV") qqcomp(list(fln,fll),legendtext=c("normal","logistic")) ppcomp(list(fln,fll),legendtext=c("normal","logistic")) gofstat(list(fln,fll), fitnames = c("lognormal", "loglogistic")) # (4) estimation of the 5 percent quantile value of # logistic fitted distribution (5 percent hazardous concentration : HC5) # with its two-sided 95 percent confidence interval calculated by # parametric bootstrap # with a small number of iterations to satisfy CRAN running times constraint. # For practical applications, we recommend to use at least niter=501 or niter=1001. # # in log10(ATV) bll <- bootdist(fll,niter=101) HC5ll <- quantile(bll,probs = 0.05) # in ATV 10^(HC5ll$quantiles) 10^(HC5ll$quantCI) # (5) estimation of the 5 percent quantile value of # the fitted logistic distribution (5 percent hazardous concentration : HC5) # with its one-sided 95 percent confidence interval (type "greater") # calculated by # nonparametric bootstrap # with a small number of iterations to satisfy CRAN running times constraint. # For practical applications, we recommend to use at least niter=501 or niter=1001. # # in log10(ATV) bllnonpar <- bootdist(fll,niter=101,bootmethod = "nonparam") HC5llgreater <- quantile(bllnonpar,probs = 0.05, CI.type="greater") # in ATV 10^(HC5llgreater$quantiles) 10^(HC5llgreater$quantCI) # (6) fit of a logistic distribution # by minimizing the modified Anderson-Darling AD2L distance # cf. ?mgedist for definition of this distance # fllAD2L <- fitdist(log10ATV,"logis",method="mge",gof="AD2L") summary(fllAD2L) plot(fllAD2L)
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