Organic contaminants and trace elements from wildfires: environmental and health impacts with a focus on North America and the Arctic-Subarctic.

Wildfires are becoming more frequent and intense worldwide, with growing recognition of their role as important sources of environmental pollution. Wildfires not only release complex mixtures of contaminants, but also emit them in large quantities, in some cases exceeding emissions from anthropogenic sources. While research has largely focused on atmospheric particulate matter (PM) and trace gases, wildfire-derived toxic trace elements and persistent organic pollutants (POPs) are also released and can exert extended impacts across environmental compartments (and wildlife) beyond the atmosphere. Smoke plumes can degrade air quality locally and regionally; while surface runoff and atmospheric deposition of contaminant-laden ash and residues can contaminate soils, sediments, and aquatic systems. This review focuses on the impacts of wildfires on potential toxic elements and POP-like organic contaminants on the environment, wildlife, and human health, with particular emphasis on North America and the Arctic. It highlights the magnitude of wildfire emissions, the extent to which wildfires influence contaminant levels across environmental media, and the potential enhancement of mobility, bioavailability, bioaccumulation, and toxicity. The review then considers potential exposure risks through multiple pathways, with particular attention to dietary exposure through northern and Arctic food webs, and related health implications.