Bioaccumulation and Neurotoxicity of Climate-driven Pollutants: A Critical Review

Abstract

Climate change is altering the environmental cycling of a diverse range of contaminants, with consequences for their bioaccumulation in food webs and their neurotoxic potential in wildlife and humans. Rising temperatures, permafrost and glacial thaw, wildfire activity, sea level rise, and altered precipitation patterns are remobilising legacy pollutants from long-term reservoirs, changing the biogeochemical conditions that govern methylation and bioavailability, and expanding the geographic and seasonal windows in which biotoxin-producing organisms proliferate. This review synthesises evidence on four broad classes of climate-modified neurotoxicants: mercury and other trace metals, legacy persistent organic pollutants together with emerging per- and polyfluoroalkyl substances, harmful algal bloom toxins, and microplastics. It examines how warming and associated hydrological change influence uptake, trophic transfer, and tissue retention of these substances, and considers the shared and distinct neurotoxic mechanisms through which they act on the central and peripheral nervous systems, including oxidative stress, blood–brain barrier disruption, neuroinflammation, and interference with neurotransmission. The review draws on peer-reviewed literature and authoritative institutional assessments to characterise exposure pathways, biomarkers, and vulnerable populations, and it identifies methodological gaps that constrain quantitative risk projections, particularly around multi-stressor interactions and the attribution of exposure trends to specific climate drivers. The synthesis indicates that climate-driven changes are unlikely to act on any single contaminant in isolation, and that cumulative, multi-pollutant exposure represents an underappreciated dimension of climate-related health risk. Future research priorities and policy implications are outlined, alongside limitations inherent to the narrative approach adopted here.