Study shows human waste in San Juan County rivers
FARMINGTON — A two-year study examining pollution in San Juan County rivers found significant levels of bacteria that indicate the presence of human waste, according to a presentation of the results Thursday.
Geoffrey Smith, a New Mexico State University professor who worked on the study, said he's conducted three similar studies in New Mexico. Those studies found feces from birds — not humans — was the major source of river pollution, he said.
San Juan County, he said, is unique.
"This is disturbing," Smith said.
More than 40 residents, business people and government officials met at San Juan College to hear the final results of the study conducted in 2013 and 2014.
Farmington Mayor Tommy Roberts and other city officials were present, as was Linda Thompson, deputy county executive officer, and a Navajo Nation Environment Protection Agency official. New Mexico Environment Department officials were also in the audience.
The San Juan Soil and Water Conservation District, and San Juan Watershed Group partnered in the study that seeks to identify land-use practices contributing to river contamination. Both are local agencies.
The study analyzed samples collected from four sites along the San Juan and Animas rivers in San Juan County and one at the Colorado-New Mexico border. Laboratory tests run on the samples showed bacteria that indicate the presence of human and animal waste.
In 2014, source tracking was added to the sample site on the state line, and high levels of bacteria associated with human waste were found. The 2013 study examined only E. coli at that site, and low levels of that bacteria were found, leading officials to initially believe the pollution must be entering the rivers in the county. They now know that conclusion was wrong.
In the 2013 results, human feces bacteria was the most common bacterium at sample sites in the county, according to the study. In the 2014 results, lab tests also found high levels of human bacteria.
Concerned about the accuracy of the results, Smith contracted an independent lab to test the samples, and the results were similar.
"It's not good news," he said.
The methods used in conducting the study are common across the country, he said.
Officials involved in the study have said it indicates that leaking septic tanks or illegal waste dumping could be polluting the rivers. But New Mexico Environment Department spokesman Jim Winchester has said he doesn't know of any evidence to support that conclusion.
Melissa May, a San Juan Soil and Water Conservation District natural resource specialist, asked members of the audience after the presentation how they might collaborate to solve the problem.
One man suggested digging wells on properties close to the rivers to monitor ground water, and May said that would be a useful component of further tests.
Roberts asked what local governments should be telling their citizens and visitors about recreating in the rivers.
Smith said the Environment Department must make that determination. But for now, he suggested telling residents and visitors to not swim in rivers after rainstorms, which can wash pollution off the land and into the water.
After the presentation, Roberts said correcting the problem will be difficult until further studies identifying the pollution sources have been completed. But human feces — as well as feces from ruminants and birds — clearly is contaminating the rivers, he said.
He said he wants city residents not to worry about their drinking water.
"I want to stress that our drinking water meets all regulation standards and is completely safe to drink," he said.
E. coli pollution in the county's rivers is not news, said Neal Schaeffer, an Environment Department scientist who was in the audience Thursday. In 2002, he studied the San Juan, Animas and La Plata rivers in the county and found such high levels of E. coli that the San Juan Watershed Group was formed, Schaeffer said.
But as for the fact that it is human waste that is the major source of the E. coli contamination, "that's new news," he said.
After Schaeffer released his study, the Environmental Protection Agency listed sections of the three rivers as E. coli contaminated, he said. Those rivers, according to EPA documents, are still contaminated with E. coli.
And they're contaminated in other ways, too, according to EPA documents. Most of the La Plata River and all of the San Juan River exceed federal sedimentation standards. The La Plata River and half of the Animas River exceed federal nutrients standards. Half of the Animas River exceeds federal phosphorus standards. The San Juan River downstream of Farmington and half of the Animas River are too cloudy. The entire Animas River is too warm.
The two-year study shows the examined rivers are contaminated, Smith said.
"We have to pinpoint where this is coming from," he said.