pollutant

Short-lived pollutants play a critical role in global warming.

"This study is a key first step in identifying pollutants in the water, even in some unexpected places like natural springs," said Arnold.

"Less studied chronic diseases such as dementia have also been shown to be associated with temperature and air pollutants," she said.

Mr Bojo Leju also says "produced water" - water released from the ground when oil is extracted and often containing hydrocarbons and other pollutants - was not properly treated.

The quality of the air can also deteriorate as pollutants build, especially in cities.