Polycyclic aromatic compounds (PACs) in the Canadian environment: Exposure and effects on wildlife

Area of Science:

• Environmental Science
• Toxicology
• Wildlife Ecology

Background:

• Polycyclic aromatic compounds (PACs) are widespread environmental contaminants.
• Wildlife, including fish, are chronically exposed to PACs through various environmental routes.
• Exposure levels are elevated near industrial sites (e.g., oil sands, aluminum smelters) and natural sources (e.g., forest fires).

Purpose of the Study:

• To review the exposure and toxicity of PACs to wildlife, with a specific focus on the Canadian environment.
• To assess current knowledge gaps regarding PACs' impact on diverse wildlife species.
• To inform regulatory strategies for protecting Canadian wildlife from PAC emissions.

Main Methods:

• Literature review of published field studies measuring PAC concentrations in wildlife tissues.
• Analysis of reported health effects associated with PAC exposure in various animal models.
• Evaluation of existing guidelines and their applicability to wildlife.

Main Results:

• Most studies measured PACs in invertebrates, fish, and birds; fewer examined amphibians and mammals.
• Generally, PAC concentrations in Canadian wildlife tissues were below the benzo[a]pyrene (BaP) guideline for human consumption.
• Documented health effects include embryotoxicity, deformities, cardiotoxicity, DNA damage, oxidative stress, endocrine disruption, and reproductive impairment.

Conclusions:

• PAC toxicity is linked to bioavailability and metabolic activation by cytochrome P450 enzymes.
• Further research is needed on diverse PACs, complex mixtures, and understudied wildlife groups (amphibians, reptiles, semi-aquatic mammals).
• Developing molecular markers for early biological response detection is crucial for robust wildlife protection strategies.