Structural alerts for the excess toxicity of acrylates, methacrylates, and propiolates derived from their short-term and long-term bacterial toxicity.

For eight acrylates, three methacrylates, and three propiolates as three subclasses of α,β-unsaturated esters, short-term and long-term bacterial toxicity with Vibrio fischeri was determined in terms of EC50 (effective concentration 50%) values for the 30-min bioluminescence and 24-h growth inhibition. To this end, experimental exposure concentrations were corrected for volatilization through a thermodynamic model based on Henry’s law constant of the compounds. Moreover, toxicity enhancements Te as the ratio of narcosis-predicted over actual EC50 were determined and discussed in terms of underlying mechanisms of reaction of the electrophiles with endogenous nucleophiles such as glutathione (GSH) and proteins. Overall, log EC50 [M] ranges from −2.28 to −3.70 (30 min) and from −2.80 to −5.28 (24 h), respectively, indicating a significantly larger sensitivity of the growth inhibition bioassay for the reactive toxicity of these Michael acceptors. The latter is also reflected in the observed toxicity enhanceme...