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Effect of dispersant on the composition of the water‐accommodated fraction of crude oil and its toxicity to larval marine fish
Author(s) -
Couillard Catherine M.,
Lee Kenneth,
Légaré Benoît,
King Thomas L.
Publication year - 2005
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1897/04-267r.1
Subject(s) - fundulus , dispersant , seawater , chemistry , environmental chemistry , larva , toxicity , bioavailability , zoology , composition (language) , acute toxicity , ecotoxicology , toxicology , biology , fish <actinopterygii> , ecology , fishery , dispersion (optics) , organic chemistry , bioinformatics , linguistics , physics , optics , philosophy
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 WAF. At 0.2 g/L, the addition of dispersant caused a two‐ and fivefold increase in the concentrations of total PAH (ΣPAH) 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; ΣPAH, 479 ng/ml). A reduction in body length was correlated with increased levels of ΣPAH ( r 2 = 0.65, p = 0.02) and not with HMWPAH. The EROD activity increased linearly with HMWPAH ( r 2 = 0.99, p = 0.001) and not with ΣPAH. Thus, chemical dispersion increased both the ΣPAH 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.