Ecotoxicity of ionic liquids is determined in EC/LC/IC/LD50 values. CAn anyone help me to get some data which would be helpful to derive EC10, EC20 or EC25?
You use PROBIT to derive the E/LCs from experimental data from your IL.
The 'data' you are looking for could only come from two sources i.e. experimental results for the specific ionic liquid you are considering or extrapolated data from structurally similar ILs. For the latter option (which seems to be related to your actual question), you need in-depth knowledge on your molecule of interest to be able to potentially apply a read-across/grouping/QSAR approach from - the available literature on aquatic toxicity data for ILs.
If sufficient and reliable data are available you may also come up with a species sensitivity distribution (SSD), which would be a valid choice for risk assessment purposes, which appears to be what you are after as you asked for different effective concentrations.