Some Asian elephants are a little shy about their eating habits. They make their way to landfills near communities on the outskirts of their forested ranges and quickly devour garbage – plastic utensils, packaging and all that. But their sinful pleasure in fast food travels with them; Elephants carry plastic and other human debris deep into forests in parts of India.
“When they defecate, the plastic comes out of the dung and settles in the forest,” says Gitanjali Katlam, an environmental researcher from India.
While much research has been done on the spread of plastic from human pollution into the world’s oceans and seas, much less is known about how such waste travels with wildlife on land. But elephants are important seed dispersers, and a study published this month in the Journal for Nature Conservation shows that the same process that keeps ecosystems functioning can transport anthropogenic pollutants to national parks and other areas. This plastic could have a negative impact on the health of elephants and other species that consumed the material after it passed through the digestive system of large mammals.
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Katlam first noticed garbage-eating elephants using camera traps while working on her doctoral dissertation at Jawaharlal Nehru University. She studied what kind of animals visit garbage dumps on the outskirts of villages in northern India. At the time, she and her colleagues also noticed plastic in elephant dung. Together with the Nature Science Initiative, a non-profit environmental research organization in northern India, Katlam and her colleagues collected elephant dung in the state of Uttarakhand.
The researchers found plastic in all manure near village dumps and in a forest near the town of Kotdwar. According to Cutlam, they only walked 1-2 miles into the forest looking for dung, but the elephants likely carried the plastic much further. Asian elephants take about 50 hours to deliver food and can walk 6 to 12 miles a day. In the case of Kotdwar, this is a concern because the city is only a few miles from the national park.
“This supports the fact that plastic pollution is ubiquitous,” said Agustina Malizia, an independent researcher at the National Council for Scientific and Technological Research of Argentina, who was not involved in this study but studied the impact of plastic on terrestrial ecosystems. She said the study is “extremely needed” as it could be one of the first reports of a very large land animal ingesting plastic.
Plastic made up 85% of the waste found in elephant dung from Kotdwar. Most of this was in food containers and cutlery, followed by plastic bags and packaging. But the researchers also found glass, rubber, fabric and other waste. Cutlam said the elephants were probably looking for containers and plastic bags because they still had leftover food inside. The dishes were probably eaten in the process.
While the garbage passes through their digestive system, elephants can ingest chemicals such as polystyrene, polyethylene, bisphenol A and phthalates. It’s unclear how much damage these substances could cause, but Katlam fears they could help reduce elephant populations and survival rates.
“It is known from other animals that their stomachs can become filled with plastic, causing mechanical damage,” said Carolina Monmany Garcia, who works with Malizia in Argentina and was not involved in Cutlam’s study.
Other animals may consume the plastic again when it enters the forest via elephant dung. “It has a cascading effect,” Cutlam said.
Cutlam said governments in India should take solid waste management measures to avoid such problems. But people can help, too, by separating their food waste from containers so that plastic isn’t accidentally eaten in large quantities.
“This is a very simple step, but very important,” she said.
“We need to be aware and understand how the excessive use of plastic affects the environment and the organisms that inhabit it,” Mealicia said.