Organ weights and histopathology of double-crested cormorants (Phalacrocorax auritus) dosed orally or dermally with artificially weathered Mississippi Canyon 252 crude oil

• Published in: Ecotoxicology and environmental safety Vol. 146; pp. 52 - 61
• Main Authors: Harr, Kendal E., Reavill, Drury R., Bursian, Steven J., Cacela, Dave, Cunningham, Fred L., Dean, Karen M., Dorr, Brian S., Hanson-Dorr, Katie C., Healy, Kate, Horak, Katherine, Link, Jane E., Shriner, Susan, Schmidt, Robert E.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 01.12.2017
• Subjects: Administration, Cutaneous; Administration, Oral; Animals; Avian; Birds - growth & development; Deepwater Horizon; Feathers - chemistry; Female; Histopathology; Kidney - drug effects; Kidney - pathology; Myocardium - pathology; Oil; Organ Size - drug effects; Organ Specificity; Organ weights; Pancreas - drug effects; Pancreas - pathology; Petroleum - toxicity; Thyroid Gland - drug effects; Thyroid Gland - pathology; Toxicity Tests; Water Pollutants, Chemical - chemistry; Water Pollutants, Chemical - toxicity; Weather; Avian; Organ weights; Oil; Histopathology; Deepwater Horizon
• ISSN: 0147-6513; 1090-2414
• DOI: 10.1016/j.ecoenv.2017.07.011

A series of toxicity tests were conducted to assess the effects of low to moderate exposure to artificially weathered Deepwater Horizon Mississippi Canyon 252 crude oil on representative avian species as part of the Natural Resource Damage Assessment. The present report summarizes effects of oral exposure (n=26) of double-crested cormorants (DCCO; Phalacrocorax auritus) to 5 or 10ml oil kg−1 day−1 for up to 21 days or dermal application (n=25) of 13ml oil to breast and back feathers every three days totaling 6 applications in 21 days on organ weights and histopathology. Absolute and relative kidney and liver weights were increased in birds exposed to oil. Additionally, gross and/or histopathologic lesions occurred in the kidney, heart, pancreas and thyroid. Clinically significant renal lesions in the orally dosed birds included squamous metaplasia and increased epithelial hypertrophy of the collecting ducts and renal tubules and mineralization in comparison to controls. Gross cardiac lesions including thin walls and flaccid musculature were documented in both orally and dermally dosed birds and myocardial fibrosis was found in low numbers of dermally dosed birds only. Cytoplasmic vacuolation of the exocrine pancreas was noted in orally dosed birds only. Thyroid follicular hyperplasia was increased in dermally dosed birds only possibly due to increased metabolism required to compensate damaged feather integrity and thermoregulate. Gastrointestinal ulceration was found in orally dosed birds only. There were no significant hepatic histopathologic lesions induced by either exposure route. Therefore, hepatic histopathology is likely not a good representation of oil-induced damage. Taken together, the results suggest that oral or dermal exposure of DCCOs to artificially weathered MC252 crude oil induced organ damage that could potentially affect survivability. •Damage documented in low to moderate oral and dermal dosing caused morbidity and mortality.•Lesions were induced in the kidney, heart, pancreas, thyroid, and liver by oral and dermal exposure.•Renal lesions could impair ability to maintain homeostasis, causing morbidity or mortality.•Dermally exposed birds had thyroid lesions either directly caused by oil or secondary to feather damage.•Minimal histologic change in the heart and liver represented a false negative for dysfunction.