An explosion on the offshore drilling rig Deepwater Horizon in the Gulf of Mexico in 2016 resulted in an oil spill and clean-up operation of unprecedented size and effort. Most research after the disaster focused on the environmental fate and impact of the oil and chemical dispersants. Studies found few health effects in marine wildlife that were linked to chemicals such as PAHs (polycyclic aromatic hydrocarbons) after the spill, possibly because their continuous exposure to large amount of oil that seeps from natural reserves under the sea floor has made them resilient to such chemicals.
However, the effects of exposure to metals in crude oil on the health of marine animals was an overlooked aspect of this disaster, so between 2010 and 2012, Dr. John Pierce Wise Jr, University of Lousville, and colleagues collected skin and blubber biopsies from sperm whales, short-finned pilot whales, and Bryde’s whales that reside in the Gulf of Mexico. They found that whales were likely to have been exposed to metals during the oil spill, resulting in concentrations higher than known averages worldwide, and that most exposure probably occurred when whales inhaled metals that were released when spilled oil was burned during clean-up operations.
These metals are known to be genotoxic, and therefore can potentially change the genetic information in cells and lead to cancers. The metal concentrations in the whales’ tissue samples decreased during the study between 2010 and 2012 but there may be ongoing health effects, and longer-term research is required to better understand the toxic legacy of the Deepwater Horizon disaster for marine wildlife.
John Pierce Wise Jr et al. 2018. A three year study of heavy metals in skin biopsies of whales in the Gulf of Mexico after the Deepwater Horizon oil crisis. Comparative Biochemistry and Physiology, Part C 205:15-25.
Prof. Andrea D. Phillott is a sea turtle biologistteaching conservation biology, ecology, and environmental studies at FLAME University in Pune, India.
Illustration by Hitesh Maruti Sonar