Even remote wildlife carries microplastics – but human proximity matters

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Microplastics are widespread worldwide and are increasingly reaching even remote habitats. This poses a threat to wildlife, as these particles can enter the body and potentially cause adverse health effects. However, little is still known about the factors that determine how much microplastic accumulates in wild mammals. An international research team led by professor Marcia Ferraz (group leader at LMU's Gene Center Munich and University of British Columbia Okanagan) and professor Michael Noonan (University of British Columbia Okanagan), has now investigated the link between human land use and microplastic burdens in free-ranging mammals in Brazil for the first time.

For their research, the scientists combined measurements of microplastic exposure in 47 wild lowland tapirs and giant anteaters with high-resolution GPS tracking data. The animals were studied in three regions of Brazil: the Amazon's Arc of Deforestation, an agricultural mosaic in the Cerrado and a relatively undisturbed ranch in the Pantanal wetland.

Highest levels found near settlements and waste disposal facilities

Their findings show that microplastics can be found even in the blood of wild animals living dozens of kilometers away from the nearest town or dump. The highest concentrations are found in animals whose habitats are closest to human settlements and waste disposal facilities. "This is one of the first studies to link what's inside a wild animal's body to where that animal lives and travels," says Noonan.

The researchers detected microplastic particles in all but four of the animals. Concentrations varied widely, ranging from zero to more than 1,200 particles per milliliter, with an average of 73.8 particles per milliliter. That average falls within the range previously reported in human blood.

Even remote habitats like the Pantanal offer no protection

In the Pantanal, the world’s largest wetland, the extent of the problem was most evident: Every animal sampled there carried microplastics, despite living more than 65 kilometres from the nearest development and more than 112 kilometres from the nearest waste facility.

Even where the human footprint was effectively zero, the team’s model still predicted a baseline of about 10 particles per millilitre. That suggests living in a remote place isn’t enough to avoid exposure. The authors point to wind- and water-borne transport as likely routes.

Health effects still unknown

“We don’t yet know what these particles are doing to the animals’ health. Most health studies use unrealistically high doses. In our own lab work, using concentrations found in reproductive fluids, microplastics affected sperm and eggs. Now we need to understand what happens in wild animals,” says Ferraz. “73 particles per millilitre may sound small. But these animals are also dealing with habitat loss, pesticides, climate change and wildfires. Plastic adds to that load, understanding their health effects is the next step.”

The researchers emphasize that the study measured exposure, not harm. It didn't assess whether the particles affect the animals' health. The authors also stress that the work shows an association rather than direct cause and effect, and that sampling the surrounding environment alongside the animals would strengthen the link.

Marcia de Almeida Monteiro Melo Ferraz et al.: Human land use drives microplastic abundance in terrestrial wildlife. Nature 2026