Comparison of empirical models for predicting lethal body burdens of neutral, organic compounds
- ENTRIX, Inc., Wilmington, DE (United States)
Three empirical models that predict lethal body burdens (LBBs) for neutral organic compounds were evaluated by using a probabilistic modeling technique. The models had the general form: log LBB = [(m log K{sub ow} + b) + (log K{sub ow} + log lipid content)]. The median and 95% predictive intervals from the model were compared to 14 independently-developed, residue-effect values from the literature for seven compounds and five aquatic species. One model, which was developed by calculating mean slopes (m) and intercepts (b) from thirteen published linear quantitative structure-activity relationships (QSARs), consistently overestimated the LBBs reported in the literature. A second model, which was developed by fitting Pimephales promelas toxicity data to a one compartment, first-order kinetic model, accurately predicted 7 of 14 (50%) reported LBBs. A third model was developed by fitting toxicity test data from three species (Cyprinodon variegatus, Mysidopsis bahia, and P. promelas) to a linear QSAR, and correctly predicted 13 of 14 (93%) reported LBBs. This study demonstrated that LBBs were accurately predicted on the basis of the toxicant`s octanol-water partition coefficient (K{sub ow}) and the lipid content of the exposed organism. The multi-species model was more accurate than the single-species model for predicting LBBs. An accurate multi-species model could not be estimated by calculating the mean slope and intercept of several single-species QSARs; the original data were required. These results verify that empirical, structure-based models are a valid approach for predicting the toxicity of neutral, organic compounds to a variety of species. This modeling approach has applications for assessing ecological risks, especially for species that have not been used in laboratory toxicity tests.
- OSTI ID:
- 212006
- Report Number(s):
- CONF-9511137--; ISBN 1-880611-03-1
- Country of Publication:
- United States
- Language:
- English
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