Scientists Detect Microplastics in Animals From Brazil’s Most Pristine Wetland

Deep in Brazil’s Pantanal, the largest and most pristine wetland in the world, the iconic tapir roams, its short snout snuffling the dirt, feeding off the twigs and seeds embedded in the ecosystem’s fertile soil. For these pony-sized mammals it’s a remote paradise, miles from any kind of human development. But running through some of their veins is an all-too-familiar imprint of industry: microplastics.

New research published Thursday in the journal Nature tracked the movements of giant anteaters and tapirs and measured the amount of microplastics in their blood.

The research found, rather unsurprisingly, that proximity to people lead to a higher level of microplastics. But more striking is that 14 animals sampled in the remote Pantanal, more than 40 miles away from the nearest town or building, also had plastic in their blood, underscoring the staggering reach of these tiny particles, which can travel through air and water.

“I honestly wish we had found no microplastics in those animals,” says Marcia Ferraz, the paper’s lead author. “Brazil has some of the most unique wildlife in the world, and it is also a place where that wildlife faces serious pressure, so finding plastic inside these animals, even in the most preserved places, was hard to see.”

The paper adds to a growing body of researching documenting microplastics in some of the world’s most untouched places. A study published in October found them in the snowpack that blankets remote parts of the Sierra Nevada. Microplastics have been linked to health problems including heart disease and cognitive decline, making their ubiquity concerning and urgent to understand.

While studies have measured where microplastics are present and how they move through marine food webs, there’s relatively little research studying all the direct and indirect ways microplastics accumulate on land. “This project nicely goes beyond simple observation of plastics contamination to quantifying the plastics and assessing a spatial relationship with a human footprint,” says Matthew Campen, an expert on microplastics in the body at the University of New Mexico, who wasn’t involved with the paper.

“From the terrestrial side of things, I would say this is new,” adds Susanne Brander, who directs scientific advancement with The Pew Charitable Trusts' safer chemicals project and was also not involved with the new study.

Ferraz, who is a professor and veterinarian and works with local governments on wildlife conservation, decided in 2018 to launch this research with one of her co-authors Michael Noonan, an assistant professor at the University of British Columbia Okanagan who studies conservation, animal movement, and statistical modeling.

Brazil, where Ferraz is from, proved in many ways an ideal spot to study how tiny bits of plastic pollute wilderness. The country is rich in diverse biomes and has seen, over the past two decades, a remarkable increase in human development in these once-remote parts. From 2001 to 2020 the human footprint index increased 26 percent globally, but in Brazil it increased by 42 percent. There were also local organizations already tracking these animals, giving the study authors data to then examine how proximity to people affected their levels.

Some of the findings were unexpected. Ferraz notes that the amount of detectable plastic was relatively consistent across the species they observed despite their different sizes, shapes, and diets. “It means that plastics are everywhere,” she says. “It’s independent of your food chain.”

One of the youngest animals observed had the highest level of microplastics in their blood. Ferraz hypothesizes it could be because younger animals are more curious. “Maybe they’re getting closer to people,” she says.

These animals weren’t picked by accident; they are integral to the ecosystem and culture of Ferraz’s homeland. She remembers drawing giant ant eaters when she was a little girl in school. Tapirs, the largest mammal native to the country, however, has garnered a somewhat less esteemed reputation. To tell someone they’re being clueless or an airhead, a Brazilian might called them an anta, the Portuguese word for tapir. But these odd-looking creatures are crucial pollinators who digest and widely disperse seeds.

“They’re the gardeners of the forest,” says Ferraz. “Without them ecosystems could collapse.”

The giant anteater’s population, meanwhile, is in decline across much of the country. In the savannah of Brazil’s Cerrado, historically a stronghold for the species, development has accelerated, increasing concerns about the well-being of the population, says Noonan. As more roads are built through their habitats to sustain the country's rapid development, anteaters are more frequently being struck by vehicles. (Read more about the work to save Brazil’s anteaters from vehicle strikes.)

One gap in the research is that the scientists’ technology was unable to measure some of the smallest and most nefarious of plastic derivatives, nanoplastics. These more readily absorb into the bloodstream, says Campen. “I do not think this changes the conclusions from the study,” he adds. “In fact, I think it would only hammer home the point further if they had provided such data.”

The study also stopped short of investigating whether there were health impacts linked to the plastics in these animals’ blood. In controlled settings, Ferraz has found that microplastics have effects on fertility, but conducting those experiments in remote parts, at times only reachable by helicopter, proves a bigger challenge.

The findings also emphasize another broad challenge to microplastic research. In the quest to understand the effects of plastic pollution, it’s becoming harder to find control zones, or places untouched by it.

“Plastic production, chemical production, it's not something we can contain in urban areas or in factories,” says Brander. “These chemicals and particles are mobile. They move around in water, they move around in the atmosphere.”