Some Asian elephants are a little shy about their eating habits. They infiltrate garbage dumps near human settlements on the edges of their forested habitats and quickly gobble up the rubbish — plastic utensils, packaging and all. But their guilty pleasure of “fast food” is traveling with them; elephants are transporting plastic and other human waste to forests in certain parts of India.
“When they defecate, the plastic comes out of the manure and is deposited in the forest,” said Gitanjali Katlam, an ecological researcher in India.
While much research has been done on the spread of plastics with human pollution in the world’s oceans, much less is known about how these wastes move with wildlife on land.
Elephants are important seed dispersers, and research published this month in the Journal for Nature Conservation shows that the same process that keeps ecosystems functioning can carry human-made pollutants into national parks and other areas. This plastic can have negative health effects on elephants and other species that consume the material after it passes through the digestive system of large mammals.
Katlam first noticed elephants feeding on garbage with surveillance cameras during her doctoral work at Jawaharlal Nehru University. She was studying which animals visited dumps on the outskirts of villages in northern India. At the time, she and her colleagues also noticed plastic in elephant dung. With the Nature Science Initiative, a non-profit organization focused on ecological research in northern India, Katlam and her colleagues collected elephant dung in the state of Uttarakhand.
The researchers found plastic all over the dung near village dumps and in the forest near the city of Kotdwar. They only walked 1.5 to 3 kilometers in the forest looking for dung, but the elephants likely carried the plastic much further, Katlam said. Asian elephants take about 50 hours to digest and can walk 10 to 20 kilometers in a day. In the case of Kotdwar, this is worrying because the city is just a few kilometers from a national park.
“This adds evidence to the fact that plastic pollution is ubiquitous,” said Agustina Malizia, an independent researcher at Argentina’s National Council for Scientific and Technical Research, who was not involved in this research but has studied the effects of plastic on terrestrial ecosystems. She said the study was “extremely necessary” as it could be one of the first reports of a large land animal ingesting plastic.
Plastic constituted 85% of the waste found in elephant dung in Kotdwar. Most of it came from food containers and cutlery, followed by plastic bags and packaging. But the researchers also found glass, rubber, fabric and other residues. Katlam said the elephants were likely looking for plastic containers and bags because they might still contain food scraps. The cutlery was likely eaten in the process.
As the waste passes through their digestive systems, elephants could be ingesting chemicals like polystyrene, polyethylene, bisphenol A and phthalates. The harm these substances can do is uncertain, but Katlam fears they will contribute to reduced elephant populations and survival rates.
“Other animals have been known to have their stomachs filled with plastic, causing mechanical damage,” said Carolina Monmany Garzia, who works with Malizia in Argentina and was not involved in Katlam’s study.
Other animals may consume the plastic again as it is transported to the forest via elephant dung. “It has a ripple effect,” Katlam said.
Katlam said India’s governments must take steps to manage their solid waste and avoid these types of problems. But individuals can also help by separating their food scraps from the containers so the plastic doesn’t end up being eaten by accident.
“This is a very simple but very important step,” she said.
“We need to realize and understand how the overuse of plastics is affecting the environment and the organisms that inhabit it,” Malizia said.
Translated by Luiz Roberto M. Gonçalves
