People in Northern Ireland love their tea, drinking an average of four to six cups a day. But when does a habit become a problem?
Possibly when all those cups result in millions of teabags which may end up in landfill, generating climate-changing methane, according to BBC.
But a tea-loving scientist at Queen's University Belfast has found a way of using that tea waste, which could improve health and save lives around the world as well as keep it out of landfills.
Dr. Chirangano Mangwandi, a lecturer in chemical engineering, suspected tea leaves could be used in wastewater treatment to remove pollutants. So, he collected the waste from a coffee shop on the university campus to test his theory.
He cleaned the used tea leaves and put them through several processes to make an absorbent product. He then tested that product's ability to remove heavy metals such as chromium and arsenic from wastewater. And it worked.
"It's just a simple case of measuring a known quantity that you put it in the wastewater, depending on the concentration level that you want to remove. Then you end up with clean water which is now free of chromium," he said.
"You also end up diverting the tea waste from landfills, which is also good for the environment," he added.
Chromium and other heavy metals are a major water pollution issue in places such as Bangladesh, where they are used in leather tanneries. They are linked to a number of health problems, including cancer.
"Being able to convert a material which is naturally abandoned into a product which can solve their problems, I think that is quite important," Dr. Mangwandi said. But the treated tea waste could have even wider applications. Dr. Mangwandi's team has been looking at its ability to remove dyes and traces of medication from water.