David Weindorf of Texas Tech University and Kevin Lombard of New Mexico State University say they found patches of discolored sludge containing elevated levels of iron, copper, zinc, arsenic and lead along the Animas River.
Weindorf says the concentrations of metals in the sludge were higher than at other sites they tested on the banks and on nearby irrigated and non-irrigated land.
About 3 million gallons of wastewater rushed out of the mine Aug. 5 after a cleanup crew supervised by the Environmental Protection Agency inadvertently breached a debris dam.
