Modeling time and temperature-dependent acute toxicity of
aromatic hydrocarbons

Tjalling Jager, Tom Parkerton, Eric Febbo, Bob Blattenberger, Martin Connelly, Dan 
Letinksi

Vrije Universiteit Amsterdam, Department of Theoretical Biology, 
Amsterdam NL
ExxonMobil Biomedical Sciences, Annandale, NJ, USA

Most toxicity tests are performed under constant exposure conditions. However, in many 
pollution cases such as oil spills, the organisms are exposed for a (short) time to varying 
concentrations and at a different temperature than in the test. Extrapolation from lab to 
field requires an understanding of the mechanisms of mortality. Several models for 
analyzing survival data explicitly consider toxicokinetics and are able to deal with data in 
time: a.o. DEBtox, critical body residue, and damage assessment models. These 
approaches are based on different assumptions on the processes underlying mortality. To 
test these models, acute toxicity experiments were performed, using trout as a model 
organism. Tests were conducted for three narcotic compounds (xylene, methyl 
naphthalene and phenanthrene) at two temperatures (5 and 18C). In these tests, survival 
was determined over time, and body residues were determined in live and dead fish. This 
data set is used to compare the performance of these models.  Implications for improving 
predictive effect modeling under field conditions will be discussed.