Looking up

Preliminary water tests show improvement

by Missy Votel

Dilution appears to be the solution as heavy metal loads along Cement Creek and the Animas River are easing.

According to the EPA, the toxic plume from the Gold King Mine had reached the confluence of the San Juan River by Saturday morning. A flyover of the area by the EPA's Airborne Spectral Photometric Environmental Collection Technology (ASPECT) team found the plume had reached Kirtland, N.M., by 4 p.m., where it appeared diluted and "far less defined." The water was reported to be muddy with an orange tinge rather than the disturbing shade of neon orange it had in Durango.

Although the breached adit at Gold King was still discharging approximately 500 gallons per minute, the flow appeared to be tailing off. The construction of new settling ponds had been completed, where the discharge was being diverted and will be treated before entering Cement Creek. Thus far, the treatment appears to be working, according to the EPA.

Also on Saturday, the EPA released the anxiously awaited results of its water testing, which showed ph levels in Cement Creek and the Animas River near Silverton returning to pre-event conditions. Heavy-metal loads were also trending to pre-spill levels, according to samples taken immediately after the blow-out, which occurred on the morning of Wed., Aug. 5.

Water samples were collected from seven locations between Silverton and 32nd Street from Aug. 5-6. Two of the locations were on Cement Creek and five were on the Animas, including a control site above Cement Creek as well as sites at Baker's Bridge and 32ndt Street. The locations were selected because historical baselines already existed for them.

According to the results, which were published in graph form, sites mimicked a sharp rise and fall in metal loads as the plume passed through. Concentrations throughout the first day showed elevated levels for copper, lead, zinc and manganese at all sites where the plume had reached, according to analysis from the EPA. (The plume had not yet completely passed through Baker's Bridge and had not reached 32nd Street at the end of the first round of testing.)

According to the graph, the Animas River below Silverton showed levels of manganese more than three times the historical average. Likewise, zinc levels were nearly five times the historical average and copper levels were 100 times the norm.

Rises in levels of lead and cadmium, which historically are in low concentration, were undetectable on the EPA graph and no numerical values were given. Arsenic and mercury were not included on the graphs.

Although low levels of many heavy metals are vital for body function, in high levels they can accumulate in the soft tissue, leading to heavy metal poisoning and severe physical and neurological damage. The heavy metals most commonly associated with poisoning of humans are lead, mercury, arsenic and cadmium.

By the morning of Thurs., Aug. 6, levels for manganese, zinc and copper at the site below Silverton had returned, or were only slightly higher than, historical averages.

The final results are preliminary and results will not be officially validated for another several days, and results may vary pending the validation process, the EPA cautioned.

In other news, Colorado Parks and Wildlife reported that the spill thus far has appeared to have minimal impacts on wildlife, in and out of the river. More than 100 fish were being monitored in cages along the river to see if the exposure to the toxic slug would result in mortality. As of Friday, only one had died - possibly from natural causes.

The Mountain Studies Institute also released promising results Saturday of tests it had conducted on macro-invertebrates – or small insects – before and after the spill.

According to the study, 20 hours after the pulse moved through, many of the small insects that inhabit the river were still intact.

This bodes well for the overall health of the river as insects are excellent indicators of water quality and stream health. Furthermore, they are the base of the food chain that supports all other aquatic life on the river.

MSI staff raced to collect data from multiple sites in Durango before the polluted water reached the city, including spots at 32nd Street and 15th Street. Furthermore, MSI has historic data at 32^nd Street that will enable comparisons of this event with the long-term status of the river.

“As soon as we heard about the release, we began sampling and testing for water quality and invertebrates. We continued to take water quality samples every one to two hours as the release hit downtown,” said Aaron Kimple, MSI's Director of Water Quality and Forest Health.

MSI's aquatic ecologist Scott Roberts noted the group does not yet know how larger-sized insects fared, as the larger invertebrates are harder to collect. Likewise, he said the ability of fish to survive depends on their ability to find food – i.e. insects – and process any metals that were absorbed through their gills and skin.

“Continued monitoring may reveal substantial impacts to aquatic life over a longer period of time, but it is good news that widespread acute mortality did not immediately occur,” says Roberts. 

For up to the date information on the Gold King Mine disaster or to see the preliminary results from the Aug. 5-6  water sampling, go to www.epaosc.org/GoldKingMine.