This app fits species sensitivity distributions to concentration data. The app is built from the R package ssdtools, and shares the same functionality. More information on ssdtools methods can be found in articles on the website.
Hint: Find and click the info icons throughout the app to find more information on a particular input.
| Concentration | Species | Group |
|---|---|---|
| 2.1 | Oncorhynchus mykiss | Fish |
| 2.4 | Ictalurus punctatus | Fish |
| 4.1 | Micropterus salmoides | Fish |
| 10 | Brachydanio rerio | Fish |
| 15.6 | Carassius auratus | Fish |
| 18.3 | Pimephales promelas | Fish |
| 6 | Daphnia magna | Invertebrate |
| 10 | Opercularia bimarginata | Invertebrate |
There are three options to provide data to the app:
Optionally, enter a toxicant name which will be used as the default plot title.
Finally, preview the data provided in the table on the right hand side of the tab. The dataset can be downloaded as CSV or XLSX.
Update fit to update the outputs after changing
selected distributions or data rescaling option.Additional information about the goodness of fit table: The columns in the goodness of fit table are the distribution (dist), the number of parameters (npars), the number of observations (nobs), the log-likelihood (log_lik), Akaike’s Information Criterion (aic), Akaike’s Information Criterion corrected for sample size (aicc), the Information Criterion differences (delta), the Information Criterion weights (wt), Bayesian Information Criterion (bic), the Anderson-Darling statistic (ad), the Kolmogorov-Smirnov statistic (ks), and the Cramer-von Mises statistic (cvm). The prediction is the model averaged (using aicc) estimate of the fit. The percent hazard concentration is the concentration of the chemical which is predicted to affect that percent of the species tested.
There are two options: Estimate the Concentration affecting/protecting a selected fraction of species (%) OR estimate the fraction of species (%) affected by a selected concentration. This affects the plot (dotted line), text displayed below the plot and calculations of confidence limits.
Select the number of bootstrap samples used to calculate
confidence limits. The recommended number of samples is 10,000,
although this can take some time to process. Select a lower number of
bootstrap samples to reduce processing time.
Distributions are treated as constituting a single mixture distribution
(as opposed to taking the mean) for calculation of model averaged
estimates. Distributions are not treated as constituting a single
distribution for calculating confidence intervals as this increases
processing time considerably.
Since confidence limits take time to calculate, they are not
calculated automatically; you must press the Get CL
button.
Format plot using various inputs in sidebar and download the plot as PNG or RDS and the confidence limits table as CSV or XLSX.
Generate a report in HTML or PDF format including the fitted distribution plot, goodness of fit table, model-averaged fit plot and table of estimated hazardous/protective concentrations. Any options selected in the app will be incorporated into the report.
Copy R code to reproduce outputs programmatically. Code is
dynamically generated based on user inputs and functions executed within
the app (e.g., code for generating confidence limits will appear after
Get CL button is clicked).