A review of the toxicology of oil in vertebrates: what we have learned following the Deepwater Horizon oil spill

Abstract

In the wake of the Deepwater Horizon (DWH) oil spill, a number of government agencies, academic institutions, consultants, and nonprofit organizations conducted lab-and field-based research to understand the toxic effects of the oil. Lab testing was performed with a variety of fish, birds, turtles, and vertebrate cell lines (as well as invertebrates); field biologists conducted observations on fish, birds, turtles, and marine mammals; and epidemiologists carried out observational studies in humans. Eight years after the spill, scientists and resource managers held a workshop to summarize the similarities and differences in the effects of DWH oil on vertebrate taxa and to identify remaining gaps in our understanding of oil toxicity in wildlife and humans, building upon the cross-taxonomic synthesis initiated during the Natural Resource Damage Assessment. Across the studies, consistency was found in the types of toxic response observed in the different organisms. Impairment of stress responses and adrenal gland function, cardiotoxicity, immune system dysfunction, disruption of blood cells and their function, effects on locomotion, and oxidative damage were observed across taxa. This consistency suggests conservation in the mechanisms of action and disease pathogenesis. From a toxicological perspective, a logical progression of impacts was noted: from molecular and cellular effects that manifest as organ dysfunction, to systemic effects that compromise fitness, growth, reproductive potential, and survival. From a clinical perspective, adverse health effects from DWH oil spill exposure formed a suite of signs/symptomatic responses that at the highest doses/concentrations resulted in multi-organ system failure.

Introductory Chapter: Issues with Oil Spills and Remote Monitoring

“…In line with the basic definition, oil is an organic compound that is soluble or readily soluble in water but not readily soluble in other liquids and is found in crude oil. An oil spill occurs when oil floats on the surface of bodies of water and is carried by the wind, currents, and tides [1][2][3][4][5].…”

“…Even without the aid of wind and water currents, the oil will spread if its surface tension is low. Oil is more likely to spread in warmer waters than in extremely cold ones since increased temperatures can reduce a liquid's surface tension [1][2][3][4][5][6][7][8][11][12][13][14][15].…”

Oil Spill in Brazil—Analysis of Vulnerabilities and Socio-Environmental Conflicts

“…Turtles, shellfish, fish, algae, among other organisms were found with remnants of the oil and many fishermen/women reported the decrease of shellfish and fish in the affected regions. Environmental exposure to oil can trigger physiological changes that depend on the duration and geographic scale of exposure, the habitat diversity of the affected site, and increased sublethal effects [1,7,[34][35][36]. Thus, these effects may be even more intense with the new traces of oil on the Brazilian coast, demonstrating that the problem is still active in these territories.…”

“…Studies warn about the possibility of environmental imbalance in locus, and also in regions relatively distant from the main point of contamination, which increases the attention in areas more sensitive to changes, such as mangrove regions. Benthic and mangrove regions are environments that are more susceptible to impacts, through the sedimentation of this material in coastal micro and macrofauna, amplifying along the chain the toxicity, genetic alterations, and other damages of the contamination [36,37]. Although toxicological tests conducted in the Baixo Jaguaribe region in the state of Ceará indicated non-significant damage to the genetic material of shellfish due to the influence of oil pollutants [38], a recent study pointed out the relationship between exposure from the 2019 oil spill and decreased growth rate of a type of microalgae of the zooxanthella species Symbiodinium glynnii, mutualistically influencing the maintenance of corals, which may undergo bleaching processes [39].…”

Intraspecific Variation in the Sublethal Effects of Physically and Chemically Dispersed Crude Oil on Early Life Stages of Atlantic Cod (Gadus morhua)

“…Research on the effects of oil on marine fishes has expanded following the Deepwater Horizon oil spill in the Gulf of Mexico in 2010. Laboratory studies after the blowout identified adverse effects of petroleum exposure, including reduced growth, impaired reproduction, and increased incidence of death and disease in several fish species (Beyer et al, 2016; Grosell & Pasparakis, 2021; McGruer et al, 2019; Murawski et al, 2021; Pasparakis et al, 2016; Takeshita et al, 2021). Early life stages of fish are known to be particularly vulnerable because the fish inhabit the upper water column and are undergoing critical developmental stages (Incardona et al, 2014; McGruer et al, 2019; Pasparakis et al, 2017).…”