Application of the target lipid model for deriving predicted no-effect concentrations for wastewater organisms.

The target lipid model (TLM) was applied to literature data from 10 microbial toxicity assays to provide a quantitative effects assessment framework for wastewater treatment plant organisms. For the nonpolar organic chemicals considered, linear relationships between the logarithm of the median effect concentrations (EC50) and log(K(OW)) conformed to the TLM for all endpoints with the exception of nitrification inhibition. Additional experimental data for the nitrification inhibition endpoint were generated for 16 narcotic chemicals using a procedure that allowed testing of volatile substances.