What it is
Microplastics reach even remote land habitats, but how landscape change shapes the amounts wild animals carry has been largely unknown. Between February 2021 and November 2022 the authors sampled blood from 26 lowland tapirs at three sites in Brazil (the Arc of Deforestation in the Amazon, an agricultural mosaic in the Cerrado and a relatively undisturbed cattle ranch in the Pantanal) and from 21 giant anteaters in the Cerrado, counted microplastic particles larger than 1 μm with confocal Raman spectroscopy, and paired the results with each animal's GPS tracking. Microplastics were found in the blood of all but four animals, at a mean of 73.8 particles per ml and a range of 0 to 1,211.3, within the range reported for human blood with spectroscopic methods. In the 40 animals with enough tracking data, concentrations rose with the maximum Human Footprint Index in an animal's home range and were higher the closer animals lived to development and to waste management facilities. Microplastics were also detected in the blood of every animal sampled in the Pantanal, more than 65 km from the nearest development and more than 112 km from the nearest waste facility.
Why it matters
Pairing each animal's GPS track with its blood sample links microplastic burdens in wild mammals to how near they range to development and waste sites. Earlier work on land wildlife mostly documented that microplastics were present; this study measures how burdens vary with individual habitat use, in a country whose mean Human Footprint Index rose by 42% from 2001 to 2020, by the authors' calculation from published Human Footprint maps. The model still predicted 10.5 particles per ml at a footprint of zero, which, with the Pantanal results, suggests to the authors that direct exposure to human-modified landscapes is unlikely to be the only driver; they point to transport by air and water as likely contributors. They suggest that limiting animals' proximity to development and waste infrastructure may reduce the burdens wildlife carries.
Underlined numbers link to their source. Every metric and quoted figure is listed under Sources and data below.
Filed underMicroplastics and Plastic Pollution, Pharmaceutical and Antibiotic Environmental Impacts, Environmental Toxicology and Ecotoxicology
