In 2012, researchers began collecting dragonfly larvae to reveal mercury pollution in protected waters. 13 years later, 21,000 samples helped create a model that can estimate freshwater mercury risk without testing every waterway

A tiny creature living beneath the surface of ponds, lakes and streams has helped scientists develop a new way to estimate mercury risk across freshwater ecosystems in the United States.

Researchers from the US Geological Survey and National Park Service used data from 21,000 dragonfly larvae collected over 13 years to develop a national-scale model that can estimate freshwater mercury risk in areas where direct monitoring data may not be available, as per a report.