In "Water Quality Report 2008," published April 2009, Marshall Municipal Utilities reported the results of a "source water assessment" by Missouri Department of Natural Resources, which looked for potentials for contamination of MMU's wells.
"In the ... report, we basically report only on those contaminants that we detect that are regulated," said MMU Environmental Services Director Ginny Ismay.
She said MMU added the unregulated substances calcium, magnesium, sodium and potassium to the report.
"We put them in anyway for quick and easy reference," Ismay added.
As stated in the publication, "(d)rinking water, including bottled water, reasonably may be expected to contain at least some small amount of contaminants. The presence of contaminants does not pose a health risk."
The concentration of barium in MMU's wells was reported as 0.044 parts per million, or ppm, which is below the maximum contaminant level, or MCL, of 2.0 ppm.
Fluoride, which is both naturally occurring in water and added to "promote strong teeth," according to the publication, was found to be present at an average of 1.06 ppm. The MCL of fluoride is 4.0 ppm.
Nitrate is toxic to humans in that it renders hemoglobin unable to carry oxygen and is responsible for so-called "blue baby syndrome." In MMU's wells, nitrates were found in concentrations of less than 0.12 ppm, far below the MCL of 10.0 ppm.
Combined nitrate and nitrites also have their MCL set at 10.0 ppm and were found in concentrations of 0.12 ppm.
Haloacetic acids were found in concentrations of 24.1 parts per billion, or ppb, which is less than half the MCL of 60.0 ppb.
Concentrations of total trihalomethanes were found at levels of 54.8 ppb, below the MCL of 80.0 ppb.
Both haloacetic acids and trihalomethanes are a by-product of drinking water disinfection.
Chlorine, which is added to control levels of microbes in water, was found at an average residual level of concentration of 1.36 ppm, which is lower than the maximum residual level of 4.0 ppm. This was the only substance not analyzed in a DNR-certified laboratory, and was instead analyzed onsite by MMU personnel, according to the publication.
Other unregulated contaminants were also found. Calcium was detected at a concentration of 19.5 ppm, magnesium at 17.9 ppm, potassium at 3.47 ppm and sodium at 23.0 ppm.
Copper and lead were found in the system, as is fairly common in areas with older buildings, due to the metals that comprise piping in those buildings.
Copper was found in concentrations at or below 0.081 ppm in 90 percent of areas checked. The MCL for copper is 1.3 ppm.
Lead was found in concentrations at or below 5.2 ppb in 90 percent of areas checked. The MCL for lead is 15 ppb.
Susceptibility to contaminants in drinking water varies from person to person. Those at the greatest risk, according to the document, are the very young and very old and those with compromised immune systems, including persons undergoing chemotherapy, persons with AIDS and those who have undergone organ transplants.
Ismay said consumers can go to the MMU Web site to see determined concentration levels of inorganic chemicals, volatile organic chemicals and synthetic organic chemicals, as well as "other analysis."
"It will show everything that we test for, the testing frequency, when it was last analyzed," she said.
The document directs consumers who want more information about contaminants to call Environmental Protection Agency's Safe Drinking Water Hotline at 1-800-426-4791.