The Economic Times

In 2011, Colorado linked 90% of Lower Gunnison River selenium pollution to farming. 11 years later, farm work cut selenium by 50%, helping the river meet standards today

For years, selenium from irrigated farmland posed a challenge for Colorados Lower Gunnison River. Irrigation can mobilize naturally occurring selenium from shale-rich soils and carry it into waterways. Efforts to improve irrigation and reduce selenium runoff began changing that picture. By 2019, the rivers selenium load at Whitewater had fallen about 46% from 1986 levels. In 2021, 66 miles downstream from Delta met the states selenium standard.