Characterization and environmental relevance of oil water preparations of fresh and weathered MC-252 Macondo oils used in toxicology testing

摘要: Abstract Comprehensive characterization of exposure media used in toxicology studies is still an area significant divergence when evaluating potential oil spill impacts. When preparing for testing, small variations simple parameters such as mixing energy, type and loading can significantly affect the concentration components to which test organisms are exposed. The key goal this study was compare contrast physical chemical compositions water mixtures prepared using fresh weathered Macondo-related oils under different conditions presence/absence dispersants. All samples were assessed presence droplets, droplet size distribution, detailed composition including polycyclic aromatic hydrocarbons (PAHs) total petroleum hydrocarbon by fluorescence (TPHF). Preparations also tested stability over a 96 h period relevant acute toxicity tests. results indicate that accommodated fractions (WAFs) produced consistent, free solutions with represented soluble used. As expected, chemically-enhanced WAFs (CEWAFs) high-energy (HEWAFs) generated large amounts micron-size droplets their corresponded closely whole oil. However, HEWAFs highly dynamic, unlike CEWAFs, much resurfaced within few hours initial preparation. Viscosity lack dispersability limiting factors preparation CEWAFs oils, did effectively introduce media. Despite benefit, sizes decreased increase weathering creating additional variable consider. Because contribution topic needs further investigation, interpretation from preparations be evaluated. TPAHs concentrations all at loadings compared publicly available water-column data analyzed during after DWH incident response they ranked above vast majority 10,828 reported. Until better column individual-component chemistry question environmental relevance pursuit toxicological more realistic continues challenge should explored.