Studies show heavy metals in river meet standards
Several entities involved in conducting studies
- The University of Arizona's Karletta Chief is leading the research team
- The study used drinking water standards established by the U.S. Environmental Protection Agency.
- The Navajo Nation EPA also has been monitoring heavy metal levels in the river.
SHIPROCK — Two studies conducted in response to the Gold King Mine spill show levels for heavy metals in the San Juan River on the Navajo Nation meet water quality standards set by tribal and federal environmental agencies.
Karletta Chief, a hydrology professor at the University of Arizona, has been leading a research team to study heavy metals in the San Juan River since fall 2015.
The study — a collaboration between the university, Tó Bei Nihi Dziil, Northern Arizona University, Diné College, Fort Lewis College and the Navajo Nation Community Health Representatives program — is also examining sediment and human health.
The Aug. 5, 2015, released 3 million gallons of heavy metals, including iron, aluminum, magnesium, lead, manganese, copper and arsenic, from a closed mine near Silverton, Colo. The contaminants wound up in the Animas River and eventually the San Juan River.
While many of those metals occur naturally, concerns develop when they impact the health of humans, Chief said during a presentation today at the Shiprock Chapter house.
For the study, the group focused on lead and arsenic because exposure to both over a long period can be harmful to humans, she said.
Chief explained that 288 water samples were collected from the river, irrigation canals and wells located in Upper Fruitland, Shiprock and Aneth in November 2015, March 2016 and June 2016.
The study used drinking water standards established by the U.S. Environmental Protection Agency, and water standards for animals and plants were screened using standards set by the National Oceanic and Atmospheric Administration.
Chief said levels for arsenic and lead were within the standards for drinking water and for plants and animals.
The group is waiting for results for sediment tests. Information from health assessments conducted on 123 participants could be released in the fall, she said.
San Juan River Dineh Water Users Inc. CEO Martin Duncan said after listening to the report that people want to know if the river water is safe to use for irrigation.
"We need to find out if the water is safe now," Duncan said.
In response, Chief said results show the levels do meet water quality standards for agricultural purposes.
Another question came from Shiprock resident Graham Biyáál, who asked Chief if she would she plant crops this season if she were a farmer.
Chief said the decision to plant crops remains with the land owner, then reiterated that results show the water meets standards for agricultural activities.
"It's up to you, to look at this information and make an informed decision. …I don't want to make that decision for you," she said.
The Navajo Nation Environmental Protection Agency also has been monitoring heavy metal levels in the river since the spill.
Results from the study were presented by Steve Austin, a senior hydrologist with the Water Quality Program under the tribe's EPA.
Austin said the program has collected water and sediment samples from 10 locations along the river and from the Fruitland and Hogback canals, which supply river water to farms on the reservation. Samples were collected from August to October 2015 and in March 2016 to April 2017.
Those samples were measured using the tribe's surface water-quality standards from 2007, which also received approval by the U.S. Environmental Protection Agency, he said.
"For water quality, none of our irrigation standards have been exceeded since 2013. We don't see an issue with irrigating from the San Juan River," Austin said.
Austin said the only time the concentration of heavy metals has exceeded standards for irrigation use was when the Fruitland canal reopened. But levels subsided after the canal was flushed.
He added that program officials will continue monitoring the river, and they are waiting for results for fish tissue testing.
Noel Lyn Smith covers the Navajo Nation for The Daily Times. She can be reached at 505-564-4636.