title: Effect of dispersant on the composition of the water-accommodated fraction of crude oil and its toxicity to larval marine fish.
abstract: Newly hatched mummichog (Fundulus heteroclitus) were exposed in a 96-h static renewal assay to water-accommodated fractions of dispersed crude oil (DWAF) or crude oil (WAF) to evaluate if the dispersant-induced changes in aqueous concentrations of polycyclic aromatic hydrocarbons (PAH) affected larval survival, body length, or ethoxyresorufin-O-deethylase (EROD) activity. Weathered Mesa light crude oil (0.05-1 g/L) and filtered seawater with or without the addition of Corexit 9500 were used to prepare DWAF and WAE At 0.2 g/L, the addition of dispersant caused a two- and fivefold increase in the concentrations of total PAH (sigmaPAH) and high-molecular-weight PAH (HMWPAH) with three or more benzene rings. Highest mortality rates (89%) were observed in larvae exposed to DWAF (0.5 g/L; sigmaPAH, 479 ng/ml). A reduction in body length was correlated with increased levels of sigmaPAH (r2 = 0.65, p = 0.02) and not with HMWPAH. The EROD activity increased linearly with HMWPAH (r2 = 0.99, p = 0.001) and not with sigmaPAH. Thus, chemical dispersion increased both the sigmaPAH concentrations and the proportion of HMWPAH in WAF. Dispersed HMWPAH were bioavailable, as indicated by a significantly increased EROD activity in exposed mummichog larvae, and this may represent a significant hazard for larval fish.
authors.affiliation: Environmental Sciences Branch, Department of Fisheries and Oceans, Maurice Lamontagne Institute, P.O. Box 1000, Mont-Joli, Quebec G5H 3Z4, Canada. couillardc@dfo-mpo.gc.ca
authors.forename: Catherine M
authors.initials: CM
authors.lastname: Couillard
authors.forename: Kenneth
authors.initials: K
authors.lastname: Lee
authors.forename: Benoît
authors.initials: B
authors.lastname: Légaré
authors.forename: Thomas L
authors.initials: TL
authors.lastname: King
mesh_terms: D000818:Animals; D019363:Cytochrome P-450 CYP1A1 / Q000378:metabolism; D005393:Fish Diseases / Q000139:chemically induced* / Q000378:metabolism; D023781:Fundulidae / Q000033:anatomy & histology / Q000378:metabolism*; D007814:Larva; D010578:Petroleum / Q000032:analysis / Q000378:metabolism / Q000633:toxicity*; D011084:Polycyclic Aromatic Hydrocarbons / Q000737:chemistry / Q000493:pharmacokinetics / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000493:pharmacokinetics / Q000633:toxicity*
chemical_list: D010578:Petroleum; D011084:Polycyclic Aromatic Hydrocarbons; D014874:Water Pollutants, Chemical; D019363:Cytochrome P-450 CYP1A1