Estimation of Toxicity of Chemicals from the MEIC List by Colony Radial Growth Rate Measurements in the Fungus Geotrichum Candidum

Abstract

The cytotoxicities of the first ten MEIC chemicals were assayed by estimation of IC50 values on cultures of the fungus Geotrichum candidum. Colony radial growth rates were measured between 24 and 48 hours after inoculation on solid media containing different concentrations of the chemicals. The IC50 values obtained in this study were higher than the human lethal blood concentrations obtained for the chemicals, but good correlation (r = 0.958) was found between human lethal blood concentrations and IC50 values obtained from growth rate measurements of G. candidum. Ferrous sulphate, methanol, ethanol and diazepam gave linear relationships between decrease in growth rates and concentration of the chemical. With ethylene glycol, the growth rate decreased linearly with the logarithm of ethylene glycol concentration.