Margins of uncertainty in ecotoxicological hazard assessment

Abstract

Margins of uncertainty in predicting toxicity from one species to another, from acute to chronic exposures and from single species to higher levels of biological organization were determined by regression and correlation analyses. Based on the acute sensitivities of 35 aquatic species to 15 compounds, no species was found to be particularly sensitive to all chemicals and the 95% uncertainty factor (UF) ranged from 3 to 1,985. Analyses of acute and chronic sensitivities for the same species to 164 chemicals resulted in the acute/chronic relationship log NOEC = ‐1.28 + 0.95 log L(E)C50 (r = 0.89) and the UF of 25.6 (where NOEC is the no observed effect concentration). Comparison of the lowest acute and corresponding ecosystem effect levels for 34 chemicals indicated the relationship log NOEC(ecosystems) = ‐0.55 + 0.81 log L(E)C50 (r = 0.77) and the UF of 85.7. As to the predictability of ecosystem effect levels from chronic single‐species data, the following relationship was found: log NOEC(ecosystems) = 0.63 + 0.85 log NOEC (r = 0.85), with a UF of 33.5. These data indicate that acute testing is not pointless; it offers a statistical base for the use of acute toxicity information in the hazard assessment of chemicals in the aquatic environment.

Simultaneous prediction of toxicity of multiple chemicals to multiple species using multi‐dimensional functional relationships

“…Note that with incomplete data, the correlation matrix must be calculated element by element, for there may be few if any chemicals that have been tested on every species. It is known that the correlations tended to be stronger if the taxa were more closely related, see Suter et al (1983), Le Blanc (1984) and Sloof et al (1986). Just how we can use this information is not yet clear.…”

Comparisons of Acute Toxicity of Selected Chemicals to Rainbow Trout and Rats

“…Interspecies variation in sensitivity to chemicals is related to taxonomic position (Suter et al, 1983;Sloof et al, 1986;Hoekstra et al 1994) and associated toxicokinetic differences. In particular, route and duration of exposure influence absorption and subsequent metabolism of compounds.…”

Guidance for treatment of variability and uncertainty in ecological risk assessments of contaminated sites

“…The results can be generalized by aggregating pairs of congeneric species, species in different genera within a family, species in different families within an order, and species in different orders within a class (Suter et al 1983;Barnthouse et al 1990;Suter 1993). The prediction interval (PI) is the appropriate measure of the variance in these relationships (Sloof et al 1986;Barnthouse et al 1990;Suter 1993). Calabrese and Baldwin (1 994) adopted these results and generated more conservative factors by calculating the 95% tolerance interval on the 95% prediction interval.…”