Comparative Rapid Toxicity Screening of Commercial and Potential “Green” Plasticizers Using Bioluminescent Bacteria

Abstract

The Vibrio fischeri bioluminescence inhibition assay (Microtox) was slightly modified to use an in-house diluent containing 2% DMSO and was successfully applied to perform a rapid toxicity screening of 24 compounds including commercial plasticizers and chemicals currently studied as potential green plasticizers. Comparison of the EC 50 values obtained indicated that 1,3-propanediol dibenzoate (PrDDB), 1,4-butanediol dibenzoate (BDDB), and dihexyl maleate (DHM) might not be good candidates as green plasticizers because of their higher toxicity (EC 50 < 1 mg L ―1 ). Results also indicated that Microtox is a useful technique to better understand the effect of key structural features on the toxicity of plasticizers. Comparison of EC 50 values of similar compounds having a different alkyl chain lengths indicated a decrease in toxicity of dibenzoate plasticizers with respect to increasing alkyl chain size. The Microtox technique that we adapted to test compounds having low solubility was proven to be useful to evaluate the toxicity of potential green plasticizers relative to commercial products. However, these results cannot be used alone to select the best candidates. The Microtox technique is complementary to biodegradation experiments and plasticizing properties tests and allows, at the development stage, the screening of a large number of potential green plasticizers on the basis of their relative toxicity.