Second-generation anticoagulant rodenticides were developed in the 1970s after rodents began evolving resistance to first-generation compounds such as warfarin. These newer compounds, including bromadiolone and difethialone, work by interfering with the vitamin K cycle, specifically the VKORC1 enzyme complex, which is essential for recycling vitamin K1 and producing functional clotting factors. A poisoned animal ultimately dies from internal hemorrhaging, but the process is slow, often taking several days. During that time, the animal can accumulate a lethal body burden of the compound and continue moving through the environment. Because SGARs are extremely persistent in liver tissue, with half-lives that can stretch from weeks to months, they do not simply vanish when the target rodent dies. Instead, they linger in the carcass and in the tissues of any animal that consumed the poisoned prey, creating a pathway for secondary poisoning up the food chain.

The research team, led by Luigi F. Richardson and Albrecht I. Schulte-Hostedde of Laurentian University, set out to answer a deceptively simple question: are the bait stations that pest management professionals deploy around buildings in urban and suburban settings leaking poison into the surrounding wild rodent community? To find out, they used snap traps to capture white-footed mice in urban wildland areas of Toronto and Vaughan, deliberately choosing trapping locations near ongoing professional baiting programs that used products containing bromadiolone and difethialone. White-footed mice are an ideal sentinel species for this kind of work. They are abundant, territorial, and have relatively small home ranges, which means that any residue found in their tissues likely reflects local exposure rather than long-distance movement from a contaminated area far away.

The results were unambiguous, if modest in absolute numbers. Out of 111 mice tested, nine carried detectable residues of bromadiolone and two carried difethialone. That is roughly one in ten animals carrying a potent anticoagulant poison in a population that was never the intended target. Concentrations in liver tissue ranged from 0.008 to 0.03 micrograms per gram for bromadiolone and from 0.008 to 0.023 micrograms per gram for difethialone. While these figures may sound vanishingly small, the authors note that concentrations in this range may be sublethal for raptors, meaning that a bird of prey feeding regularly on contaminated mice could accumulate a toxic burden over time even if no single mouse delivers a lethal dose.

Perhaps the most striking spatial finding is how far from the bait stations the contaminated mice were caught. SGAR residues were detected in individuals trapped at distances of 0 meters, 5 meters, 20 meters, 40 meters, 70 meters, and 100 meters from active rodenticide stations. This pattern suggests that the compounds are not simply leaking a few centimeters into the surrounding soil or being picked up only by animals that wander directly into a bait box. Instead, the exposure appears to be distributed across the landscape, likely through a combination of mechanisms. Poisoned commensal rodents may disperse into wildland areas before dying, contaminated carcasses may be scavenged or partially consumed by mice, and bait itself may be carried out of stations by target rodents or other animals. Invertebrates that feed on bait have also been proposed in the broader literature as a potential vector, though the present study did not directly test that pathway.

When the researchers compared the SGAR-positive mice with the SGAR-negative ones, they found no significant differences in sex, age, body condition, distance to the rodenticide source, capture date, or capture site. In other words, there was no obvious profile of the contaminated mouse. Exposure did not concentrate in juveniles, in animals in poor condition, or in individuals trapped closest to bait stations. This lack of pattern is itself informative. It suggests that exposure risk is broadly distributed across the local mouse population rather than confined to a particular demographic subset or a narrow zone around bait deployment. It also complicates any attempt to predict which individuals or areas are most at risk based on simple proximity measures.

That said, the study did note that four of the exposed individuals were classified as being in poor body condition. While the sample size is too small to draw firm conclusions about a causal relationship between rodenticide burden and physical condition, the observation is consistent with the possibility that sublethal exposure imposes physiological costs. Anticoagulant poisoning, even at doses that do not kill outright, can cause chronic internal bleeding, anemia, and reduced fitness. For a wild mouse, those costs could translate into reduced survival or reproductive output, and for the predators that depend on mice as prey, a population of weakened or poisoned rodents represents a hidden hazard embedded in a normal food source.

The broader context of this work is a growing body of evidence that anticoagulant rodenticides have become pervasive contaminants in urban and suburban food webs. Studies in Chicago have documented widespread exposure among common urban mesopredators, while research in British Columbia has found these compounds in endangered American badgers and fishers. Raptors in Ontario have already been shown to carry SGAR residues, and the compounds have been detected in unexpected places, from urban reptiles in Australia to frogs and freshwater fish in Germany. What has been missing, particularly in Ontario, is a clear understanding of the exposure pathways, the specific mechanisms by which the poison moves from a locked bait station to a hawk’s bloodstream. By demonstrating that nontarget wild rodents near professional baiting programs carry SGAR residues, this study helps fill that gap and points to a plausible link between routine pest control and the contamination of predators.

The authors also raise the possibility that some of the exposure they detected may have come from residential SGAR use rather than from the professional baiting programs they focused on. In Ontario, as in many jurisdictions, consumers can purchase rodenticide products for home use, and these products are often deployed with less oversight than professional applications. Distinguishing between professional and residential sources of exposure is methodologically difficult, but the finding underscores that the problem is not confined to any single sector of the pest control industry. It is a landscape-scale contamination issue driven by the sheer volume of persistent anticoagulants being deployed across urban environments, whether by licensed technicians or by homeowners dealing with a mouse in the garage.

The implications for policy and practice are significant. Several jurisdictions, including parts of the United States and the European Union, have already moved to restrict public access to SGARs or to limit their use in certain settings, and Health Canada has imposed restrictions on commercial-class rodenticides in agricultural contexts. This study adds weight to the argument that urban and suburban baiting practices deserve similar scrutiny, particularly near wildland fragments that support native rodent populations and the predators that feed on them. The authors suggest that the pest management industry’s use of rodenticides in these settings is likely causing some degree of nontarget spillover in Toronto and the Greater Toronto Area. As cities continue to densify and the boundary between built and natural habitat grows ever more porous, the question is no longer whether rodenticides reach nontarget wildlife, but how much exposure ecosystems can absorb before the cumulative toll on predators and other wildlife becomes unsustainable. For now, the white-footed mice of Toronto’s ravines are carrying the answer in their livers, one contaminated individual at a time.

Subject of Research: Nontarget exposure of white-footed mice to second-generation anticoagulant rodenticides in urban Ontario

Article Title: Exposure of nontarget white-footed mice (Peromyscus leucopus) to second-generation anticoagulant rodenticides in an urban context

Article References: Richardson, L. F., & Schulte-Hostedde, A. I. (2026). Exposure of nontarget white-footed mice (Peromyscus leucopus) to second-generation anticoagulant rodenticides in an urban context. Environmental Monitoring and Assessment, 198(11), Article 1195. https://doi.org/10.1007/s10661-026-16038-x

Image Credits: AI Generated

DOI: 10.1007/s10661-026-16038-x

Keywords: anticoagulant rodenticides, SGARs, white-footed mouse, Peromyscus leucopus, bromadiolone, difethialone, urban wildlife, ecotoxicology, secondary poisoning, Toronto, pest control, nontarget exposure

The stakes of the study are considerable. Roughly one in three refugees worldwide experiences depression, anxiety, or post-traumatic stress, and these conditions can persist for decades after displacement. Yet the dominant frameworks used to understand and treat this suffering—what researchers call WEIRD psychology, shorthand for Western, Educated, Industrialized, Rich, and Democratic—tend to conceptualize trauma through a narrowly individual lens. This approach, the authors argue, overlooks the social, historical, and collective dimensions of refugee distress and produces siloed findings with limited relevance to the communities themselves. For the Eelam Tamil community, which fled a brutal 26-year armed conflict and genocide in Sri Lanka, the consequences are acute: Toronto now hosts the largest Tamil population outside Sri Lanka, an estimated 200,000 people, and the community is grappling with spiking suicide rates among its young adults—deaths that resurface intergenerational wounds largely unreported in the news.

Methodologically, the study is a third phase of a Decolonizing Participatory Action Research project, and its design reflects a deliberate refusal of extractive research practices. During early consultations, Tamil community members told the team they no longer wanted pathologizing studies about themselves or celebratory narratives of ‘superhero’ resilience. They asked instead for conversations about healing futures. The researchers responded with an arts-based sequence: participants first created memory-box autobiographies and body-map drawings—embodied, visual representations of lived experience—before moving into the study’s centerpiece, three virtual avatar-based community circles held on a 3D collaboration platform called FRAME. Each 90-minute circle brought together four participants, two Tamil peer researchers, and the lead author in an immersive space where everyone appeared as an avatar under a pseudonym.

The choice of avatars was not a gimmick but a technical and ethical solution to a real problem. Toronto’s Tamil community is tight-knit, and participants consistently asked whether they could remain anonymous when discussing sensitive topics. The platform also offered an antidote to the ‘Zoom fatigue’ that had accumulated through years of pandemic videoconferencing, fostering presence and creativity instead. Participants found the software intuitive—no one required a tutorial—and communicated verbally or through text chat. The circles drew methodological guidance from Indigenous talking-circle traditions and were intentionally loosely structured, with prompts following participants’ preferences. A licensed counsellor was available offline in case of distress, though no participant accessed that support. Notably, participants described the circles themselves as ‘a site of healing,’ with several asking for the sessions to continue beyond the study.

Through reflexive thematic analysis of the transcripts, field notes, and member-checking sessions, seven elements of community healing crystallized. The first is agency and self-determination. Participants described frustrating encounters with therapists who judged their decisions—such as maintaining contact with older family members—without understanding the collective logic behind them. One participant drew an analogy to harm reduction, noting that healthcare respects individual choice in addiction treatment but rarely extends the same courtesy to refugee family dynamics. The second element, historical trauma-informed care, addresses the exhaustion of having to explain genocide and its aftermath to every new provider. ‘I would want them to have some context that I don’t have to spoon feed,’ one participant said, ‘because I find it exhausting.’ Participants also warned that the label ‘trauma-informed’ is often applied vaguely, and that trauma may manifest somatically in South Asian communities in ways practitioners are not trained to recognize.

Cultural safety formed the third element: spaces where Tamil culture could be expressed with pride rather than translated for outsiders. Participants wanted Tamil practitioners and peer supports, while acknowledging that cultural safety is not guaranteed by shared identity alone—several noted that queer Tamils may not feel safe even within community-run spaces, an intersectional caveat the researchers take seriously. The fourth element, intergenerational connectedness and belonging, surfaced a poignant asymmetry: younger participants were hungry for elders’ stories, while parents and grandparents, protective by habit, guarded them from the worst. Participants proposed facilitated dialogues with community elders, noting that conversations flow more easily with those outside one’s own family, where judgment and tension give way to patience and active listening.

The fifth element, destigmatized access and delivery, generated some of the study’s most practical ideas. Shame around mental health—and classist stigma against those who seek community services—keeps many Tamil families away. Participants suggested embedding healing activities in spaces the community already trusts: temples, where sessions could be framed as religious programming for older generations, and even Tim Hortons, where Tamil workers already share vulnerable conversations over coffee. The sixth element, holistic and authentic approaches, produced a strikingly concrete inventory: Tamil-language classes that teach the vocabulary of mental health, communal cooking and gardening that celebrate rather than mourn the culture, music and dance workshops featuring porattam resistance songs at village get-togethers, financial literacy coaching to interrupt what participants identified as intergenerational financial trauma, an ‘Anna/Akka’ big-brother-big-sister mentorship program, and emotional wellness workshops teaching skills that many participants said their upbringing never provided.

The seventh element, truth telling as justice, proved the most politically charged. Participants argued that community healing cannot proceed while the genocide they fled remains publicly denied and their protests dismissed. Several drew painful comparisons to the global solidarity extended to Ukraine, contrasting it with the silence around state violence against Black and Brown populations—and, in one account, to arms supplied to the Sri Lankan government. For these young adults, acknowledgment, accountability, and reparations are not political luxuries appended to therapy; they are prerequisites for healing itself. The researchers frame this within liberation psychology, which privileges historical memory, testimony, and collective action over the forgiveness-first frameworks common in mainstream clinical work.

The authors synthesize these seven elements into what they call a praxis of community healing, ‘actively existing in a dialectic’: communities must simultaneously recognize and resist interlocking systems of oppression while cultivating radical hope for justice and liberation. Existing at either pole alone, they argue—drowning in resistance or detaching into fantasy—is detrimental; the act of holding both is itself a healing process. The study has limitations the authors acknowledge candidly: only one male participant took part, pointing to entrenched stigma around vulnerability for Tamil men, and queer Tamil representation was limited. The findings are context-specific and not generalizable, though the researchers argue the broader principles can transfer to other refugee communities if adapted through genuine partnership. As the first known use of avatar-based community circles in health sciences research, the method itself may prove durable—the lead author is already working with community organizations to establish ongoing virtual healing spaces. The study’s core message, distilled from its participants, is blunt and demanding: there is futility in saving parents from war only to lose their children to despair in a new country, and no ‘one size fits all’ intervention, however well-intentioned, can substitute for healing designed with, by, and for the community itself.

Subject of Research: Community healing and intergenerational trauma among second-generation Tamil refugee young adults studied through participatory avatar-based virtual reality circles

Article Title: Healing our intergenerational wounds: a praxis of community healing envisioned by refugee young adults engaging in participatory avatar-based community circles

Article References: Thambinathan, V., Wylie, L., Ganesh, D., Ramesh, L., & Kinsella, E. A. (2026). Healing our intergenerational wounds: a praxis of community healing envisioned by refugee young adults engaging in participatory avatar-based community circles. International Journal for Equity in Health, 25(1), Article 232. https://doi.org/10.1186/s12939-026-02993-x

Image Credits: AI Generated

DOI: 10.1186/s12939-026-02993-x

Keywords: refugee mental health, community healing, intergenerational trauma, Tamil diaspora, participatory action research, avatar-based circles, virtual reality, liberation psychology, cultural safety, historical trauma, decolonizing methodologies, Toronto