State says high lead reading in Jackson water report no cause for alarm

Last month, Jackson released its annual water quality report and though one test site was found to be in excess of the safe range for lead, the Missouri Department of Natural Resources says that customers can consider their water to be safe.

The Environmental Protection Agency requires that community water systems circulate a Consumer Confidence Report each year no later than July 1. For contaminants that are not expected to vary significantly year to year, the state allows monitoring less than once per year. Testing dates on Jackson's report range from 2006 to 2011.

The one reading that fell outside of safe levels was lead. During the 2008-2010 period, reported values ranged from 1.09 parts per billion to 15.8 parts per billion.

Although the goal is for drinking water to contain no lead at all, the action level, or concentration that the DNR says should trigger action by water suppliers for lead is 15 parts per billion, just under the highest reading in the range Jackson reported.

However, the standard to use to judge whether the water is generally safe is Jackson's "90th percentile" reading of 10.7 parts per billion, said Renee Bungart, director of communications for the DNR. That means that 10 percent of test results fall above 10.7 parts per billion and 90 percent fall below that level.

"Water suppliers are allowed to have 10 percent of their samples be above 15 parts per billion with no consequences," Bungart said. "If 90 percent of their samples are good, then regulators are reasonably sure that there is not a corrosion problem with the water. However, the department does encourage systems to follow up on high samples and retest those homes. They usually come back below 15 parts per billion."

The one Jackson site that tested high for lead was a vacant single-family residence on East Main Street, according to Erica Collins, Jackson staff engineer. The sample was recorded in August 2010 and the DNR did not request retesting, she said. The next-highest reading fell below the action level, she said. All report samples were taken at city residences, not at the system's six well sources.

Lead is rarely found in source water, according to the EPA. It usually enters tap water through corrosion of plumbing materials.

"Homes built before 1986 are more likely to have lead pipes, fixtures and solder. However, new homes are also at risk: even legally 'lead-free' plumbing may contain up to 8 percent lead. The most common problem is with brass or chrome-plated brass faucets and fixtures which can leach significant amounts of lead into the water, especially hot water," said the EPA in information available online to consumers.

The Centers for Disease Control and Prevention says that "most studies show that exposure to lead-contaminated water alone would not be likely to elevate blood lead levels in most adults," even exposure to water with a lead content close to 15 parts per billion. Risks vary depending upon "the individual, the circumstances, and the amount of water consumed. For example, infants who drink formula prepared with lead-contaminated water may be at a higher risk because of the large volume of water they consume relative to their body size."

Overall, the report shows that Jackson had no violations of drinking water regulations in 2011. Readings fell below safe limits for all other tested contaminants, including arsenic, barium, chromium, fluoride, nitrate-nitrite, disinfection byproducts, copper, radium and other radioactive particles, calcium carbonate, calcium, chloride, carbonate, iron, magnesium, manganese, n-Butylbenzene, nickel, potassium, sodium, sulfate, xylene and zinc. The total dissolved contaminants and acidity were also evaluated and found to be below the DNR's maximum contaminant level.

salderman@semissourian.com

388-3648

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101 Court St., Jackson, MO