Ionic Liquids (ILs) are considered as the potential replacement of industrial organic solvents because of their salient physical and chemical properties, for example, ionic nature, low vapor pressure, and good solubility properties. These properties make ILs feasible for potential application. Industrialization of ILs has a potential to adversely affect and pose risk to the ecosystem because of their toxic nature. However, the conventional research on the ILs is mainly carried out by performing acute the toxicity assessment of individual species for individual ILs which is termed as effect assessment. Effect assessment for individual ILs is insufficient for the ecotoxicological risk assessment of ILs. Subsequently, effect assessment of single ILs on one species is not sufficient to evaluate risk. The main objective of the current research was to estimate the safe environmental concentrations (SECs) of ILs towards three bacterial strains V fischeri, E coli and S vacuolatus by Chemical Toxicity Distribution (CTD) method. CTDs provided the SECs for a group Imidazolium NTf2 ILs toward three bacteria. E coli was the most sensitive species amongst three species when exposed to the selected group of ILs with 2.976 � 10 -4 mmol/L as SEC. © Published under licence by IOP Publishing Ltd.