Toxic effects of orally ingested oil from the Deepwater Horizon spill on laughing gulls

Authors

Katherine E. Horak, USDA/APHIS/WS National Wildlife Research CenterFollow
Steven J. Bursian, Michigan State UniversityFollow
C. K. Ellis, USDA National Wildlife Research Center
K. M. Dean, Abt Associates
J. E. Link, Michigan State UniversityFollow
Katie C. Hanson-Dorr, USDA National Wildlife Research CenterFollow
F. L. Cunningham, Mississippi State UniversityFollow
K. E. Harr, Urika Pathology, LLCFollow
C. A. Pritsos, University of NevadaFollow
Karen L. Pritsos, University of Nevada
Katherine A. Healy, US Fish and Wildlife ServiceFollow
Dave Cacela, Abt AssociatesFollow
S. A. Shriner, USDA/APHIS/WS National Wildlife Research CenterFollow

Document Type

Article

Date of this Version

2017

Citation

Ecotoxicology and Environmental Safety 146 (2017) 83–90.

Comments

U.S. government work.

Abstract

The explosion of the Deepwater Horizon oil rig released millions of gallons of oil into the environment, subsequently exposing wildlife, including numerous bird species. To determine the effects of MC252 oil to species relevant to the Gulf of Mexico, studies were done examining multiple exposure scenarios and doses. In this study, laughing gulls (Leucophaeus atricilla, LAGU) were offered fish injected with MC252 oil at target doses of 5 or 10 mL/kg bw per day. Dosing continued for 27 days. Of the adult, mixed-sex LAGUs used in the present study, 10 of 20 oil exposed LAGUs survived to the end of the study; a total of 10 of the oil exposed LAGUs died or were euthanized within 20 days of initiation of the study. Endpoints associated with oxidative stress, hepatic total glutathione (tGSH), oxidized glutathione (GSSG) and reduced glutathione (rGSH) significantly increased as mean dose of oil increased, while the rGSH:GSSG ratio showed a non-significant negative trend with oil dose. A significant increase in 3-methyl histidine was found in oil exposed birds when compared to controls indicative of muscle wastage and may have been associated with the gross observation of diminished structural integrity in cardiac tissue. Consistent with previous oil dosing studies in birds, significant changes in liver, spleen, and kidney weight when normalized to body weight were observed. These studies indicate that mortality in response to oil dosing is relatively common and the mortality exhibited by the gulls is consistent with previous studies examining oil toxicity. Whether survival effects in the gull study were associated with weight loss, physiologic effects of oil toxicity, or a behavioral response that led the birds to reject the dosed fish is unknown.