By Emily Ornberg, Contributing Writer

Hydrogen and oxygen may not be the only elements found in Chicago’s tap water.

The City of Chicago and the U.S. Environmental Protection Agency are reconsidering the way they test for lead in homeowners’ drinking water after EPA researchers discovered last year that the sampling method they have used for 20 years may need to be revised.

Standard practice calls for testing the lead level in the first liter of water drawn from the tap to see if it contains more than 15 parts per billion of lead, the level that triggers regulatory action. If no more than 10 percent of tested homes exceed the limit, the city is considered in compliance under the Safe Drinking Water Act, as it has been since the EPA set the standards in 1991, but the EPA recently studied a new testing procedure in which the lead level in the first 14 liters of water drawn from a tap is considered.

They found half of the 29 homes they visited had at least one sample with more than 15 parts per billion of lead, which didn’t show up until the seventh to ninth liters were drawn.

Lead, even at low levels, can cause a range of health problems, including behavioral disturbances, learning disabilities and brain damage. Typically, the source of lead in drinking water is the pipes in a

house’s plumbing.

Older homes sometimes have lead pipes that can erode, allowing some of the lead to seep into tap water.

Miguel Del Toral, regulations manager for the EPA Region 5 Ground Water and Drinking Water Branch, said Chicago has been taking action to minimize lead contamination since the EPA established its Lead and Copper Rule in 1991.

“Chicago has been treating the water way before [this] project started,” Del Toral said, noting that since 1992 the city has added small doses of a phosphate mixture called orthophosphate to the water. “The orthophosphate chemically binds with the lead pipes, and it forms the protective film on the inside.”

Chicago’s water has “met or exceeded all standards for water quality” since the Lead and Copper rule was established, said Tom LaPorte, spokesman for the Chicago Department of Water Management.

“We are working with U.S. EPA on review of [the] Lead and Copper Rule,” LaPorte said. “In the meantime, we have no choice but to follow current protocols. However, we are awaiting guidance from the U.S. EPA.”

The review of the Lead and Copper Rule has been in progress for approximately one year.

“We conducted three rounds of testing in the spring, summer and fall of 2011 to take a look at the current sampling protocol to evaluate whether we need to make any changes,” Del Toral said.

LaPorte explained that the current protocol for sampling is to draw a single one-liter sample from the tap after the water has been sitting stagnant for at least six hours. But EPA researchers are studying whether sequential testing using multiple one-liter samples taken from the same tap is more revealing of problems, LaPorte said.

Del Toral said a decision on future test methods will be forthcoming.

“We will be writing up the results [of the testing], and it will be reviewed externally,” he said. “If they agree with the findings, it’ll be published.”

LaPorte suggested that anyone concerned about lead should run tap water for five minutes before ingesting it. The more time water has been sitting in metal pipes, the more lead it may contain. The higher the lead level is, according to Del Toral, the more adverse the health effects. Children 6 years old and younger are most at risk.

“So we strongly recommend that pregnant women, infants and children should eliminate or minimize any lead exposure … because of the vulnerability of the children,” Del Toral said. “They have a much smaller body mass and the concentration can get much higher in their blood.”

LaPorte added that everyone should be cautious, not just high-risk groups.

“There is no safe level of lead,” he said. “Our goal is to eliminate it.”