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Improving the design and conduct of aquatic toxicity studies with oils based on 20 years of CROSERF experience
Citation:
Stubblefield, B., M. Barron, G. Bragin, M. DeLorenzo, B. de Jourdan, B. Echols, D. French-McCay, P. Jackman, J. Loughery, T. Parkerton, A. Renegar, AND J. Rodriguez-Gil. Improving the design and conduct of aquatic toxicity studies with oils based on 20 years of CROSERF experience. AQUATIC TOXICOLOGY. Elsevier Science Ltd, New York, NY, 261:106579, (2023). https://doi.org/10.1016/j.aquatox.2023.106579
Impact/Purpose:
The purpose of this article is to communicate recommendations for advancing oil spill science related to the toxicity testing of petroleum. The paper will be published in a high impact journal and will present consensus recommendations on laboratory toxicity testing of petroleum. The impact is that adoption of the recommended methods will faciliate greater standardization and utility of oil toxicity tests that will improve hazard assessment and ulimately may improve oil spill preparedness, response and impact assessment.
Description:
Laboratory toxicity testing is a key tool used in oil spill science, spill effects assessment, and mitigation strategy decisions to minimize environmental impacts. A major challenge in oil toxicity testing is how to replicate real-world spill conditions, oil types, weathering states, receptor organisms, and modifying environmental factors under laboratory conditions. Oils and petroleum-derived products are comprised of thousands of compounds with different physicochemical and toxicological properties, and this leads to challenges conducting and interpreting oil toxicity studies. Experimental methods used to mix oils with aqueous test media have been shown to influence the aqueous-phase hydrocarbon composition and concentrations, hydrocarbon phase distribution (i.e., dissolved phase versus in oil droplets), and the stability of oil:water solutions which, in turn, influence the bioavailability and toxicity of the oil containing media. Studies have shown that small differences in experimental methods can lead to large differences in test results. Therefore, it is imperative to standardize the methods used to prepare oil:water solutions in order to improve the realism and comparability of laboratory tests. The CROSERF methodology, originally published in 2005, was developed as a standardized method to prepare oil:water solutions for testing and evaluating dispersants and dispersed oil. However, it was found equally applicable for use in testing oils and oil-derived products. The goals of the current effort were to: (1) build upon two decades of experience to update existing CROSERF guidance for conducting aquatic toxicity tests and (2) to improve the design of laboratory toxicity studies for use in hazard evaluation and development of quantitative effects models that can then be applied in spill assessment. Key issues to be discussed and considerations for experimental designs include species selection (standard vs field collected), test chemical (single compound vs whole oil), exposure regime (static vs flow-through), exposure metrics, toxicity endpoints, and quality assurance and control.
URLs/Downloads:
DOI: Improving the design and conduct of aquatic toxicity studies with oils based on 20 years of CROSERF experience