Making sense of ecotoxicological test results: towards application of process-based models
Jager, T., Heugens, E. H. W. snd Kooijman, S. A. L. M. 2006.
Making sense of ecotoxicological test results: towards application of process-based models.
Ectoxicology, 15: 305 - 314
Abstract
The environmental risk of chemicals is routinely assessed by comparing
predicted exposure levels to predicted no-effect levels for
ecosystems. Although process-based models are commonly used in
exposure assessment, the assessment of effects usually comprises
purely descriptive models and rules-of-thumb. The problems with this
approach start with the analysis of laboratory ecotoxicity tests,
because only a limited amount of information is extracted. Standard
summary statistics (NOEC, ECx, LC50) are of limited use in part
because they change with exposure duration in a manner that varies
with the tested species and the toxicant. As an alternative,
process-based models are available. These models allow for toxicity
measures that are independent of exposure time, make efficient use of
the available data from routine toxicity tests, and are better suited
for educated extrapolations (e.g., from individual to population, and
from continuous to pulse exposure). These capabilities can be used to
improve regulatory decisions and allow for a more efficient assessment
of effects, which ultimately will reduce the need for animal
testing. Process-based modeling also can help to achieve the goals
laid out in REACH, the new strategy of the European Commission in
dealing with chemicals. This discussion is illustrated with effects
data for Daphnia magna, analyzed by the DEBtox model.