By Suzette Osei.
Climate change and well-water draining of SLV aquifers may be elevating the concentration of heavy metals in drinking water. According to a recent update released by the San Luis Valley Ecosystem Council’s well water quality testing, initial results reveal elevated levels of several heavy metals including arsenic, uranium, manganese, lead and copper. These findings from community-wide well water sampling were part of a 5-year study to assess the impacts of drought on water quality and quantity. The study is led by Dr Kathy James and is a partnership between the SLV Ecosystem Council, the University of Colorado and the School of Public Health.
Seven hundred, thirty-six well water samples were taken from wells in six counties in the SLV including Saguache, Alamosa, Rio Grande and Costilla Counties. Of these, 21% of samples had at least one metal above the Environmental Protection Agency (EPA) recommended levels and 4% had at least two metals above the EPA recommendation.
The elevated levels of heavy metals which naturally occur in groundwater systems in the SLV included arsenic (10% of wells), uranium (7%), manganese (7%), tungsten (3%), copper (4%) and lead (2%). The update from the Council notes that while trace amounts of these heavy metals were found in the samples, the percentage of wells with clinically significant levels decreases when one considers the EPA and other local health agency thresholds. For example, the EPA regulations limit lead in drinking water to 15 micrograms per liter (ug/L). In the council’s study, the incidence of lead above 5ug/L in their study was 1%. By contrast, the EPA sets the level of arsenic at 10ug/L and the council’s study shows that levels of arsenic in their study above 5ug/L was 15%. These findings are therefore preliminary since they do not report specifically on EPA standards.
Many of these heavy metals are naturally occurring chemical elements widely distributed in the Earth’s crust, and levels can vary by locality. The effects of lead toxicity on the mental and physical development—in particular of children—are well known. The effects of the other heavy metals such as arsenic, uranium, manganese and copper range from gastrointestinal, nervous system, and kidney effects up to the potential for cancer with long term exposure. The researchers plan to provide mappings of regions for particular risks including the presence of compaction of soil structures within various aquifers. The latter may lead to the withdrawal of water such that water cannot be recharged in a way to decrease the accumulation of heavy metals.
Recently, the Crestone Charter School discovered elevated lead levels when water testing at the school. Director Thomas Cleary indicated that—as part of state regulatory requirements—water testing done at the school during the past summer showed higher than recommended lead levels in low-flow faucet pipes. This finding was confirmed on repeat testing. A risk assessment conducted by the school’s staff confirmed that high-flow pipes located in the kitchen did not have a similar concern. The low-flow pipes are located in the bathroom areas and project zones (art room and science room) which are not drinking water sources for the school kids.
As an additional precaution Cleary said signs were placed at low-flow pipe areas to emphasize that kids should not use these as drinking water sources. Remediation measures include the placement of drinking jugs throughout the building for student use. In addition, the state is funding water filtration bottle-filling stations which are being set up at low-flow pipe areas and will be tested to ensure lead levels are below threshold before the school children are permitted to access these stations.
Baca Water and Sanitation District’s manager, Diego Martinez, confirmed that routine testing, which includes the source of water to pipes and well water, have been conducted appropriately and that there is no concern for lead or other heavy metals.