Arsenic, uranium still present at allowable levels

McCOOK, Neb. -- The McCook water treatment plant recently celebrated its ninth consecutive year without a drinking water standard violation, however, there are contaminants in the city water residents should be aware of.

Two regulated contaminants with a health risk at any level, arsenic and uranium mass, are present in McCook's water system at levels close to the highest level allowed, according to the Annual Water Quality Report released last week. The report lists several contaminants present in McCook's water and indicates all of them are at levels that meet the Environmental Protection Agency's water standards. Arsenic and Uranium, however, represent the only contaminants present that have a contaminant goal level of zero.

Arsenic is allowed in municipal water at levels up to 10 parts-per-billion and has a "Maximum Contaminant Level Goal" of zero. The goal level is set at the level where there is no known or expected risk to health, while the maximum allowed level is set as close to the goal level as is feasible given the best available treatment technology, according to the city drinking water report.

McCook's water contained 8.1 ppb of arsenic in 2015, up from the previous 7.31 ppb reported in 2012.

The major sources of arsenic in drinking water is erosion of natural deposits, runoff from orchards and runoff from glass and electronics production wastes, according to the EPA website. Some people who drink water containing arsenic well in excess of the MCL for many years could experience skin damage or problems with their circulatory system, and may have an increased risk of getting cancer, according to the EPA.

Uranium mass is allowed in municipal water at levels up to 30 ug/L (micrograms-per-liter) and also has a goal level of zero. McCook's water contained 22.5 ug/L of uranium in 2015, up from the 19.8 ug/L reported in 2014.

Certain rock types have naturally occurring trace amounts of "mildly radioactive" elements, leading to uranium contamination of water systems, according to the EPA website. Exposure to uranium in drinking water may result in toxic effects to the kidney. Some people who drink water containing alpha emitters, such as uranium, in excess of the MCL over many years may have an increased risk of getting cancer, according to the EPA.

More information about contaminants and potential health effects can be obtained by calling the EPA's Safe Drinking Water Hotline at 1-800-426-4791.

The City of McCook Annual Water Quality Report with information on other contaminants reported in 2015 is available online at: www.cityofmccook.com