Development
and Practical Application of Petroleum
and Dispersant Interspecies Correlation Models for Aquatic Species
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Abstract
Assessing
the acute toxicity of oil has generally relied on existing
toxicological data for a relatively few standard test species, which
has limited the ability to estimate the impacts of spilled oil on
aquatic communities. Interspecies correlation estimation (ICE) models
were developed for petroleum and dispersant products to facilitate
the prediction of toxicity values to a broader range of species and
to better understand taxonomic differences in species sensitivity.
ICE models are log linear regressions that can be used to estimate
toxicity to a diversity of taxa based on the known toxicity value
for a surrogate tested species. ICE models have only previously been
developed for nonpetroleum chemicals. Petroleum and dispersant ICE
models were statistically significant for 93 and 16 unique surrogate-predicted
species pairs, respectively. These models had adjusted coefficient
of determinations (adj-<i>R</i><sup>2</sup>), square errors
(MSE) and positive slope ranging from 0.29 to 0.99, 0.0002 to 0.311,
and 0.187 to 2.665, respectively. Based on model cross-validation,
predicted toxicity values for most ICE models (>90%) were within
5-fold
of the measured values, with no influence of taxonomic relatedness
on prediction accuracy. A comparison between hazard concentrations
(HC) derived from empirical and ICE-based species sensitivity distributions
(SSDs) showed that HC values were within the same order of magnitude
of each other. These results show that ICE-based SSDs provide a statistically
valid approach to estimating toxicity to a range of petroleum and
dispersant products with applicability to oil spill assessment