I' d like to calculate lethal concentration (LC50) or effect concentration (EC50) in our study with daphnids. The US EPA suggest to derive values using both the probit method and the trimmed Spearman-Karber method. Do you know if there is a (free) software or an R code to perform these analyses?
Hi Diego,
You can use the R package 'drc' in order to analyse your data, typically growth or survival data. For reproduction, you may need more sophisticated statistical models to take into account the discrete nature of the data and a possible overdispersion. For reproduction data analysis specifically, I suggest you to visit the MOSAIC web site, http://pbil.univ-lyon1.fr/software/mosaic/, and to go the 'repro' module.
Best regards,
Sandrine
Thank Sandrine,
Did you use drc for 48h LC50 determination? drc uses probit or trimmed method?
I don't know another software for this calculations, but I'm sure that should be an option. Others researchers could help you better.
The MOSAIC server is currently on maintenance; it will available by the end of the day. I'm using drc when appropriate, but I don't know specifically for probit, sorry.
We use the POLO LeOra software to estimate LC50,LC95, etc. It´s a very useful and easy tool to use for Probit analysis.
try Dr. Russell Erickson's TRAP version 1.22 free download option from the EPA web site: http://www.epa.gov/med/Prods_Pubs/trap.htm
Dear Diego,
Try this: Stat4Tox:
http://ihcp.jrc.ec.europa.eu/our_labs/eurl-ecvam/laboratories-research/predictive_toxicology/qsar_tools/stat4tox
If you know your way around R, you should be OK. The package has a lot of methods. Problem: need to install a specific version for R (2.10.1) and some packages. Just follow the instructions.
Diego,
can you give me some informations about the use of R for LC50 calculation?
Best regards
Hi, Please check the link below,
Best
http://pages.ucsd.edu/~tkousser/Beck%20Notes/longitude20041short.pdf
Use Minitab, Tutorial available at
http://www.iasri.res.in/ebook/EBADAT/1-Computer%20Usage%20and%20Statistical%20Software%20Packages/10-MINITAB%20Some%20Exercises%20Using%20Minitab.pdf
Www.leora-software.com is the new website for the PoloSuite software. The 3rd Edition of Bioassays with Arthropods will be available this fall.
Recommend everyone who runs aquatic toxicity bioassays to include the TRAP program. It is free and will provide both good insights as to goodness-of-fit about your data as well as LC50s, etc. It can be downloaded here: https://archive.epa.gov/med/med_archive_03/web/html/trap.html
a free excel file is available in the internet based on Finney probit analysis method for LC50
Polo the best one and easier
Stat calc
Stat direct
Jmp
Ldp-line
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