Use of joint toxic response to define the primary mode of toxic action for diverse industrial organic chemicals
- Environmental Protection Agency, Duluth, MN (United States). Environmental Research Lab.
- AScI Corp., Duluth, MN (United States)
An important aspect of understanding how multiple toxicants jointly act involves defining the primary mode of toxic action for the chemicals of interest. The authors have explored the use of 96-h acute toxicity tests with juvenile fathead minnows and primarily binary chemical mixtures to define the primary acute mode of toxic action for diverse industrial organic chemicals. Their investigation mainly considered the two special cases of noninteractive joint action known as concentration (simple similar) and response (independent) addition. The different forms of joint toxicity with binary mixtures were graphically illustrated by isobole diagrams. Designated as the mode of action-specific reference toxicants were 1-octanol, phenol, and 2,4-dinitrophenol. It was observed from binary isobole diagrams that a chemical with a similar primary mode of toxic action to that of a reference toxicant would display a concentration-addition type of joint action with the reference toxicant over the entire mixture ratio range. Dissimilar chemicals with very step concentration-response curves generally showed an interaction that was less-than-concentration additive, but consistently demonstrated a joint toxicity that was greater than predicted by the response-addition model. The more-than-concentration additive and complex isoboles that are indicative of interactive toxicity were not commonly observed in the experiments.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 118685
- Journal Information:
- Environmental Toxicology and Chemistry, Journal Name: Environmental Toxicology and Chemistry Journal Issue: 9 Vol. 14; ISSN 0730-7268; ISSN ETOCDK
- Country of Publication:
- United States
- Language:
- English
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