Fig. 3. Toxic unit (TU) additive median lethal concentration (LC50mix) of (A) Perionyx excavatus and (B) Eisenia andrei exposed to a mixture of methyl tert-butyl ether (MTBE)
and tert-butyl alcohol (TBA) for 24, 48, and 72 h. Bars represent the 95% upper and lower confidence limits of LC50mix
.