by Emily Anthes On a frigid February night in 2023, a freight train carrying toxic chemicals derailed in East Palestine, Ohio. For days, the train’s hazardous contents spilled into the surrounding soil, water and air. It was an environmental and public health catastrophe, and efforts are underway to monitor the long-term health effects on the people of East Palestine. But one team of scientists is focused on a different group of local residents: the dogs. After the derailment, the researchers recruited dog owners in and around East Palestine, asking them to attach chemical-absorbing silicone tags to their pets’ collars. The preliminary results, which have not yet been published, suggest that dogs living closest to the crash site were exposed to unusually high levels of certain chemicals. The researchers are now analyzing blood samples from the dogs to determine whether the chemicals may have triggered genetic changes associated with cancer. “This is what we should be doing in the wake of any of these disasters,” said Elinor Karlsson, a geneticist at UMass Chan Medical School and the Broad Institute, who is leading the research. “The pets that live in our homes are being exposed to the same things we’re going to be exposed to.” Our pets breathe the same air, drink the same water and often sleep in the same beds that we do. And yet, there is relatively little research on how environmental toxins and pollutants affect our animal companions. That is an enormous missed opportunity, experts said. Our pets, they argued, are ideally situated to act as environmental health sentinels, helping scientists identify hazards that transcend species barriers. Understanding more about how pollution affects pets could ultimately yield insights that improve animal and human health. “I do like to use the analogy of the canary in the coal mine, with this one distinction, which is that canaries were sacrificial,” said Dr. Audrey Ruple, a veterinary public health researcher at Virginia Tech. “Our dogs are not. We care deeply about our companion dogs and our companion animals.” The Air Out There In 2020, California experienced a record-setting wildfire season, one that often left the skies filled with smoke. On particularly bad days, Stephen Jarvis, a graduate student in the Bay Area, found himself with headaches, irritated eyes, shortness of breath and even chest pains. He also noticed the effects in his partner’s asthmatic cat, Manolo. “On days when the air quality was worse, his symptoms would flare and he would have a hard time breathing,” Jarvis said. Last week, Jarvis, now an assistant professor at the London School of Economics, published a paper suggesting that Manolo’s breathing problems were not a one-off. He and his colleagues reviewed five years of veterinary data from across Britain, alongside data on the levels of airborne fine particulate matter, which is one of the main pollutants in wildfire smoke and a well-known human health hazard. When air pollution rose, so did the number of veterinary visits for cats and dogs, the researchers found. If the nation kept air pollution below the threshold recommended by the World Health Organization, it could prevent between 80,000 and 290,000 vet visits per year, they concluded. “That’s a lot of angst and a lot of money off the table for pet owners,” Jarvis said. It’s a sobering finding, especially given the fact that climate change and intensifying wildfires are expected to make air quality worse in the coming decades. “When we are considering how to protect ourselves from unhealthy air, we should also be thinking about our pets and wildlife,” said Olivia Sanderfoot, an ecologist at Cornell University who studies the effects of smoke on wild animals. Smoke inhalation can cause an array of respiratory problems in animals, including coughing and shortness of breath. Studies have also begun to link wildfire smoke to other health consequences, including eye infections and cellular stress in dogs and heart problems and blood clots in cats. Birds are especially vulnerable because they are highly efficient breathers, extracting more oxygen from the air than mammals do. Unfortunately, Sanderfoot said, that means that they are also “processing higher concentrations of all of the nasty stuff” in polluted air. “They are more sensitive overall to air pollution than we are.” Heavy Burdens Cats and dogs, which tend to spend a lot of time on or near the ground, could be at elevated risk from other chemical contaminants. Compared with humans, they may have more exposure to cancer-causing chemicals used in lawn care or the heavy metals, like lead, that tend to accumulate in household dust. In 2014, when lead began leaching into the drinking water in Flint, Michigan, there was reason to believe that pets were especially vulnerable. Unlike people, pets usually “subsist wholly” on tap water, said John Buchweitz, a veterinary toxicologist at Michigan State University. After Buchweitz and his colleagues set up lead-screening clinics for local dogs, they found several animals whose results were of “extreme concern,” including three Australian shepherds all living in the same household. The dogs had been losing weight and behaving strangely, and all three had elevated lead levels in their blood. Buchweitz was alarmed; he knew that the family living there also had young children. “I personally reached out, contacted the health department and said, ‘This house needs to be investigated,’” he recalled. Officials subsequently found that the drinking water at the home contained enough lead to pose a clear danger to people and animals. Known Unknowns Although a chemical spill, wildfire or water crisis can present an acute, immediate health risk, many environmental health hazards are harder to identify: Does regular, low-level exposure to a particular pollutant, for instance, increase someone’s lifetime cancer risk? Pets have shorter lives than people, and are more likely to live them out in a single geographic location, making it easier for scientists to tease out some of these subtle effects. Plus, the devotion of pet owners helps facilitate data collection, experts said. “People are worried about their pets,” said Karlsson, who leads Darwin’s Dogs, a large community science project that aims to identify the genetic and environmental contributors to canine health and behavior. “And as a scientist, that’s an opportunity. Because if people are concerned about it, then they’re going to help us with the work.” Tens of thousands of American dog owners have enrolled their pets in Darwin’s Dogs and similar initiatives, including the Dog Aging Project and the Golden Retriever Lifetime Study. Among other data, these projects are collecting information on some of these dogs’ everyday exposure to chemicals, measuring the levels of herbicides in their urine, mailing out chemical-absorbing silicone dog tags and asking owners to submit samples of their dogs’ drinking water. To Ruple, who led the Dog Aging Project’s pilot studies with silicone tags and drinking water, the owners seemed more eager to participate than they would have been in research on their own environmental health risks. “I think that people are quite suspicious of science at this point in time,” she said. “But their love for their dogs overrides whatever distrust they might have.” And the dogs, in turn, can give back, helping scientists identify chemicals that put both humans and animals at risk. After all, Ruple noted, the word “sentinel” refers to someone whose job is keeping watch. “That’s what we have always used dogs for,” she said. “Guardians of our livestock, guardians of our family, guardians of our homes.” And in a toxic world, perhaps, guardians of our health. This article originally appeared in The New York Times.
