The Colorado health department announced Tuesday it’s OK to eat fish out of the Animas River, evidenced by results from extensive sampling following the Gold King Mine spill.
On Aug. 5, 2015, an Enivornmental Protection Agency led crew breached an earthen dam holding back mine wastewater in the Gold King Mine, about 10 miles north of Silverton, sending heavy-metal laden sludge down the Animas River.
Metal loading into the Animas watershed is not a new problem, but health officials held concerns that after the massive release, fish exposed to elevated levels of potentially toxic substances in the water as well as sediment on the river bottom would accumulate the toxins over time.
Indeed, the Colorado Department of Public Health and Environment’s results showed metal levels were higher in the spring samples of five brown and five rainbow trout than fish taken in the fall, but not at levels that would be of concern to human health.
“Detection limits for the metals in the spring were somewhat higher than those for the fall but ... all results fell below risk screening levels,” the announcement said.
The health department tested for 13 metals – aluminum, arsenic, beryllium, cadmium, cobalt, copper, lead, manganese, mercury, nickel, selenium, uranium and zinc. However, beryllium and cobalt were not tested in the spring samples.
According to the results, fish collected in August 2015 showed levels of beryllium, cadmium, lead, and uranium less than the detection limits, while low levels of the other metals were detected.
The fish collected in March 2016 showed detectable levels of aluminum, arsenic, and mercury, while all other metals were less than detection limits.
The two metals of concern – aluminum and mercury – showed increases from fall 2015 to spring 2016, which warrants further monitoring and testing, the health department said.
“While we have no concerns at this time with aluminum in the fish tissue with regards to human health, the apparent increase in aluminum levels from August to March could represent a slight accumulation of aluminum in fish tissue,” the department said.
For mercury, the only toxic substance the state of Colorado regulates for fish, tissue samples ranged from 0.03 to 0.22 mg/kg – below the state’s 0.3 mg/kg limit but above the EPA’s more stringent 0.15 mg/kg.
The results also showed an increase from fall to spring.
“Further investigation of mercury levels in Animas River fish may be warranted, but we do not yet have enough evidence to warrant concern for human health,” the state said.
The fish population in the Animas River over the past decade has declined, which is attributed to a number of factors, including less water in the river, urban runoff, higher water temperatures and chronic exposure to heavy metals.
A survey conducted by Colorado Parks and Wildlife this fall showed encouraging signs: more fish of quality size and proof that stocked juvenile fish were surviving winter.
“We haven’t seen that (survival rate) for a while,” said Jim White, an aquatic biologist with CPW. “Its been a really nice fish year. Its definitely been more abundant than years past.”
Local fishermen, too, noted the more favorable fishing conditions, with larger trout, more bugs and quality catches throughout summer. But, as is customary with people who intimately fish the Animas, there’s an unspoken understanding not to eat the catch.
“We don’t really encourage people to catch fish out of the Animas to eat them based on fact the water is high in metals and as a fly shop it’s more about sport than anything,” said Andy McKinley, a manager at Duranglers.
Cole Glenn, a shop manager at San Juan Anglers, also said he sways customers to release any catches in the river, if not for the questionable water quality, then to help preserve the fishery.
“The river’s not glowing or anything, but certainly there’s a little residual stuff in there,” he said.
Glenn couldn’t recall any fishing friends he knows that eat trout out of the Animas, but years ago, before he knew better, he tried some.
“It was all right.”
jromeo@durangoherald.com