Wildlife toxicology involves investigating how various environmental pollutants alter the physiology and anatomy of wildlife. These effects can determine the general fitness and survival of these animals by influencing their reproductive success, health and general well-being in the wild.
Animals in the wild can be exposed to many harmful pollutants through the food and water they eat, the air they breathe, as well as the environment in which they live. Researchers around the world have made major advances in understanding how the presence of many environmental pollutants can create challenges in wildlife conservation efforts. This research supported efforts to eventually develop measures to prevent the adverse effects of this pollution in the wild.
Recent estimates suggest that at least 14 million tons of plastic are dumped into the ocean each year. Since about 80% of water debris is made up of plastic pollutants, marine wildlife is inevitably affected, threatening the health and safety of many of the world’s food resources as well.
Previously, researchers were primarily interested in documenting animal ingestion of plastic, rather than focusing on the effects of plastic ingestion on marine wildlife. By shifting their focus, researchers can broaden their understanding of the physical symptoms and toxicity that ingestion of plastic can have on individual organisms, as well as its population-level effects on marine wildlife.
By understanding the impact of plastic ingestion at the marine population level, researchers can begin to clarify the degree to which animals are exposed to certain pollutants. Moreover, this information will provide new insights into the reproductive toxicity of these pollutants on different organisms.
In addition to demonstrating the impact of plastic ingestion at the population and organismal level, toxicologists are also interested in determining how different biological factors can influence the susceptibility of some wild animals to the effects of plastic ingestion. As a result, researchers can decide which animal groups to target for both research and conservation efforts.
Despite the implementation of both national and international bans, as well as regulations for the release of various industrial chemicals into the environment, the levels of these pollutants in different parts of the world, particularly the Arctic, remain consistently high. In addition to previously discovered chemicals, new and alternative Arctic chemicals have also been discovered and described as Chemicals of Emerging Arctic Concern (CEACs). Although some of the CEACs identified to date are considered to be less persistent than previous persistent organic pollutants (POPs), the distinct physical and chemical properties of these chemicals have led to increased concerns about their potential adverse biological effects.
Perfluorooctane sulfonic acid (PFOS) and hexabromocyclododecane (HBCDD) are two types of CEACs that possess high toxicity potential and have been identified throughout the Arctic. The accumulation of these chemicals, as well as ancient persistent organic pollutants that were also detected in high concentrations in top Arctic predators, have further complicated understanding of their combined effects on wildlife.
Indeed, the presence of both POPs and CEACs in Arctic wildlife increases the potential for their cumulative and/or synergistic effects on exposed wildlife. This can result in a wide range of immunological, reproductive, and endocrine effects on these organisms.
Taken together, toxicological research on these compounds in Arctic wildlife, especially top predators, is needed to understand the transfer of these chemicals into Arctic food webs and whether their levels are increasing, decreasing, or remaining the same. This information will subsequently provide insight into how the accumulation of these chemicals may threaten biodiversity in the Arctic.
The widespread use of pesticides worldwide has inevitably increased wildlife exposure to these chemicals. Although there are many media that can be used to monitor pesticide contamination, the atmospheric dispersal of these chemicals has remained a challenge for toxicology assessment.
Pesticides often pollute the air either through the evaporation of pesticide droplets before they reach their target, the drift of fumes after pesticides are sprayed from the target area, or by winds carrying contaminated soil particles to locations far from the target.
In addition to the risks of inhaling pesticide-contaminated air, wildlife can also be exposed to these chemicals through ingestion of leaves contaminated as a result of pesticide drift. Although it is unlikely that wildlife would suffer acute toxicity due to this route of exposure, chronic toxicity can cause a wide range of sub-lethal effects on wildlife that can affect various organ systems, as well as their offspring.
- Barton, C. C., & Inerua, Mo. (2020). Chapter 30- Environmental Toxicology: Wildlife. Information Sources on Toxicology (5th ed.); 337-344. doi: 10.1016/B978-0-12-813724-6.00030-X.
- Avery-Gomm, S., Borrelle, S.B., & Provencher, JF (2018). Linking plastic ingestion research to marine wildlife protection. Macro Ecology 637–638; 1492-1495. doi: 10.1016/j.scitotenv.2018.04.409.
- Sonne, C., Dietz, R., Jenssen, B.M., et al. (2021). Emerging pollutants and biological effects on Arctic wildlife. Trends in ecology and evolution 36(5); 421-429. doi: 10.1016/j.tree.2021.01.007.
- Zaller, J. G., Kruse-Pla, M., Schlectriemen, U., et al. (2022). Pesticides in ambient air, affected by surrounding land use and weather, pose a potential threat to biodiversity and humans. Total Ecology 838(2). doi: 10.1016/j.scietotenv.2022.156012.