Some Asian elephants are a little shy about their eating habits. They sneak into landfills near human settlements on the fringes of their forest habitats and quickly gobble up waste — plastic utensils, packaging, and all. But their guilty pleasure for fast food travels with them – elephants transport plastic and other human waste deep into forests in 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 into the spread of plastic from human pollution to the world’s oceans and seas, significantly less is known about how such waste moves with wildlife on land. But 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 wild areas. This plastic can have negative health effects on elephants and other species that have eaten the material once it has passed through the digestive systems of large mammals.
dr. Katlam first saw elephants feeding on waste on trail cameras during her Ph.D. work at Jawaharlal Nehru University. She studied which animals visited garbage dumps on the outskirts of villages in northern India. At the time, she and her colleagues also saw plastic in the elephants’ dung. With the Nature Science Initiative, a non-profit organization focused on ecological research in Northern India, Dr. Katlam and her colleagues have elephant dung in Uttarakhand state.
The researchers found plastic in all the manure at village dumps and in the forest near the town of Kotdwar. They only walked a mile or two into the forest in search of dung, but the elephants probably carried the plastic much further, Dr Katlam said. Asian elephants take about 50 hours to pass food and can walk four to twenty kilometers in a day. In the case of Kotdwar, this is worrying as the town is only a few kilometers away 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 Scientific and Technical Research Council, who was not involved in this research but studied the effects of plastic on terrestrial ecosystems. She says the study is “extremely necessary” as it may be one of the first reports of a very large land animal ingesting plastic.
Plastic made up 85 percent of the waste in Kotdwar’s elephant dung. The bulk of this came from food containers and cutlery, followed by plastic bags and packaging. But the researchers also found glass, rubber, dust and other debris. dr. Katlam said the elephants were probably looking for containers and plastic bags because they still had food in them. The utensils were probably eaten during the process.
As waste passes through their digestive systems, the elephants may ingest chemicals such as polystyrene, polyethylene, bisphenol A and phthalates. It’s uncertain what harm these substances can do, but Dr. Katlam fears they could contribute to a decline in elephant numbers and survival rates.
“Other animals are known to have their stomachs filled with plastic, causing mechanical damage,” said Carolina Monmany Garzia, who works with Dr. Malizia in Argentina and was not involved in Dr. katlam.
Other animals can consume the plastic again once it has been transported into the forest via the elephant dung. “It has a cascading effect,” said Dr. katlam.
dr. Katlam said governments in India should take steps to manage their solid waste to avoid this type of problem. But private individuals can also help by separating their food waste from the containers, so that plastic is not accidentally eaten so much.
“This is a very simple step, but a very important one,” she said.
“We need to realize and understand how the overuse of plastic affects the environment and the organisms that live in it,” said Dr. mealizia.