Unexpectedly High PFAS Levels Found in Canadian Sea Otters Near Urban Centers

Oxford University Press reports that a paper published in Environmental Toxicology and Chemistry detected elevated concentrations of per- and polyfluoroalkyl substances (PFAS), often called forever chemicals, in Canadian sea otters along the Pacific coast. The study, titled Concentrations of Per- and Polyfluoroalkyl Substances in Canadian Sea Otters (Enhydra lutris) are Higher Near Urban Centers, links contamination to urban activity and common PFAS sources such as food packaging, nonstick cookware, textiles, cosmetics, firefighting foams, and electronics. PFAS are persistent in the environment and can bioaccumulate, potentially causing immunotoxicity, organ damage, endocrine disruption, and reproductive impairments in wildlife. Sea otters, long-lived and top predators, are especially vulnerable via prey exposure and possible maternal transfer. The findings highlight broader risks to marine ecosystems and food webs near urbanized coastlines. This summary is published by The GIST and provided by Oxford University Press.

Overview

The Environmental Toxicology and Chemistry study, summarized by The GIST and provided by Oxford University Press, reports unexpectedly high levels of per- and polyfluoroalkyl substances (PFAS) in Canadian sea otters (Enhydra lutris) found along the Pacific coast near urban centers. PFAS, often termed forever chemicals, have a broad range of industrial and consumer uses, including food packaging, nonstick cookware, waterproof textiles, cosmetics, firefighting foams, and electronics. The study suggests that urban activity and associated PFAS releases contribute to elevated exposures in wildlife that occupy coastal habitats.

“Forever chemicals persist in the environment and accumulate in wildlife,” - Environmental Toxicology and Chemistry study authors

Key Substances and Significance

PFAS constitute a large family of substances characterized by carbon-fluorine bonds that resist degradation. The Canadian otter samples showed concentrations of these substances that are concerning given the otters’ feeding habits and longevity. PFAS exposure can disrupt immune function, damage organs, interfere with hormonal systems, and affect reproduction in wildlife. While some PFAS have been banned or phased out in various regions, these chemicals remain pervasive due to their environmental persistence and long-range transport, making coastal otters vulnerable even far from industrial sites.

“Per- and polyfluoroalkyl substances travel through water, soil, and the atmosphere and resist degradation,” - Environmental Toxicology and Chemistry study authors

Exposure Pathways and Population Implications

Otters typically accrue PFAS through the food chain, consuming prey species that have themselves accumulated these substances. Maternal transfer and lactation may further contribute to exposure in offspring. The study emphasizes that long-lived, predatory marine mammals like sea otters are particularly susceptible to PFAS accumulation, which can influence population health across generations. This is especially pertinent for otters inhabiting or visiting urban-adjacent coastal areas where PFAS sources cluster.

“The concentrations were higher near urban centers,” - Environmental Toxicology and Chemistry study authors

Broader Ecological and Policy Implications

The findings contribute to growing concerns about PFAS in marine ecosystems, signaling potential ripple effects through marine food webs. The persistence of PFAS in the environment means coastal and marine mammals may carry higher body burdens, with possible consequences for disease susceptibility and reproductive success. The study underscores the need for continued monitoring, source-reduction strategies, and regulatory measures to curb PFAS releases, particularly in waterfront urban areas where wildlife interfaces with polluted waterways.

“Forever-chemicals have a lasting presence in ecosystems and demand stronger controls,” - Environmental Toxicology and Chemistry study authors

Publication and Research Context

The paper is published in Environmental Toxicology and Chemistry (2025), and the research was conducted on Canadian sea otters along the Pacific coast. The analysis highlights urban proximity as a key determinant of PFAS exposure, aligning with prior evidence of urban-industrial PFAS sources influencing nearby wildlife. The Oxford University Press summary notes the study’s significance for understanding how human activity near coastlines affects wildlife health and the resilience of marine ecosystems known to support predator-prey dynamics along temperate coasts.

For readers seeking more detail, the article references the DOI 10.1093/etojnl/vgaf226 and points to the study’s focus on urban-centered PFAS contamination as a driver of elevated levels in a sentinel species.