Multiple efforts to address elevated selenium concentrations in the Lower Gunnison and Colorado Rivers within Colorado are on-going
The most active effort is related to the Selenium Management Program (SMP) facilitated by the US Bureau of Reclamation.
Details and archives can be found here
Additionally – there is a voluntary group of landowners, water users and agency folks working in a cooperative and proactive fashion to “protect the agricultural heritage” of the basin. Unfortunately technical difficulties have temporarily rendered the Gunnison Basin and Grand Valley Selenium Task Forces website inoperable. It is hoped that http://www.seleniumtaskforce.org/ will be back on line soon
In 2018, the USGS published a report analyzing streamflow and selenium loads in the Gunnison and its tributaries near Delta. It can be found here.