The effect of benzene, phenol and catechol an the run of the logarithmic phase of growth of Chlorella vulgaris, Beijerinck 1890 cultures

We estimated the toxic effect of benzene, phenol, and catechol on the logarithmic phase of growth of Chlorella vulgaris, Beijerinck 1890 cultures; the compounds show various degrees of toxicity to the algae. A concept was developed concerning each compound's toxicity index EC50/(T2-T1) The concept assumes the calculation of the index as well as benzene, phenol, and catechof-ináuced inhibition of test cultures growth f(T2-T1,) in T2-T1, interval which corresponds in our experiment to the logarithmic phase of control culture growth. f(T2-T1,) was proved to remain in linear relation to the initial concentration of the investigated substances in culture medium. Also, it was found that the values of EC50/(T2-T1), calculated by probit methods, are characterized by confidence intervals comparable to those determined for EC50/96 and EC50/Tmax (the indexes were determined at hour 96 and Tmax, respectively)