Assessing microbial toxicity of 2‐ethoxyethanol and BIS (2‐chloroethyl) ether by a modified spread plate method

Microbial populations indigenous to three industrial waste stabilization pond influents were assayed using the two organics separately and in combination. Individually, the LC50 values were 17,400 mgl−1 for 2‐ethoxyethanol and 2,160 mgl−1 for bis(2‐chloroethyl)ether. The growth inhibition of heterotrophic microorganisms exposed to combinations of the two organics could be accurately predicted by a multiplicative survival model based on individual exposures to the two organics. No synergism or antagonism was observed.