Crude oils are comprised of thousands of compounds, and after refining, many more products are derived from crude oils. When crude oils or refined petroleum products are released into the environment, they are altered through a series of processes known as weathering. Determining exposure of cetaceans to oil is a challenging task due to the complexity of the substances that make up oil as well as the rapid metabolism and excretion of oil-derived compounds by vertebrate species. The effects of oil in cetaceans have been investigated to some extent following oil spills and in a small number of past experimental exposure studies, which are now prohibited. The wide range of reported effects include poor body condition, calcium imbalance, inflammation, reproductive failure, lung and adrenal gland damage, altered hepatobiliary function, immune changes and increased susceptibility to infections, impaired stress response, and death. The three main routes of oil exposure in cetaceans are respiratory, dermal, and oral, as in most animals. The limited number of published reports including historical in vivo studies relating to effects linked to a specific route are discussed. In the wild, cetaceans are likely to be exposed to oil via more than one route, and reported effects are rarely attributed to a specific pathway of exposure. To date, the greatest and most detailed source of information on the effects of oil exposure on cetaceans is related to the 2010 Deepwater Horizon (DWH) oil spill in the northern Gulf of Mexico. It is extensively reviewed along with other studies. Effects observed at both the organismal level and population effects (mortality events, reproductive success, and growth rate) are discussed along with effects observed in other relevant species. Overall, the historical literature, combined with recent substantive findings following the DWH oil spill, suggests that cetaceans are at high risk of adverse effects from oil exposures, and these effects have importance at both the individual and population levels. Future research needs and recommendations are provided together with a list of specific and general research questions that remain unanswered regarding long-term oil toxicity in cetaceans.
|Title of host publication||Marine Mammal Ecotoxicology|
|Subtitle of host publication||Impacts of Multiple Stressors on Population Health|
|Number of pages||19|
|State||Published - Sep 6 2018|
- Oil spill