Water testing in Chicago raises concerns about screening process for lead
Jenny Kelly pours water from her kitchen faucet in her Chicago home. Kelly had her water tested for lead by the Tribune, and while it was not over the legal action level, it was close, which worries her. (José M. Osorio/Chicago Tribune)
Those results suggest that the way water is screened for lead nationwide may inaccurately gauge how much of the toxic metal leaches into our water.
For example, the highest lead levels in most of 29 Chicago homes tested were found in the sixth or seventh liter of water, which is not tested by water utilities. Some lead levels were more than twice the federal standard.
In late spring, officials with the U.S. Environmental Protection Agency were surprised to find high lead levels in another small study of Chicago tap water. Now they are trying to determine why those levels were found and what it means for consumers as well as policies that govern water testing.
Experts say there is no safe level of exposure to lead, which can leach into water from lead pipes outside the home or from plumbing and fixtures inside. The heavy metal has been known to cause diminished IQs in children, even at low levels, and heart attacks and strokes in adults from chronic exposure.
When local utilities test tap water in homes, they must alert residents and try to lower lead levels if the lead concentrations found exceed 15 parts per billion in more than 10 percent of samples.
The city of Chicago hasn't exceeded that limit in nearly 20 years, and neither have the majority of communities across the nation. But regulators, scientists and public health officials are worried the flawless results are the result of outdated testing methods, government agencies gaming the system or both.
"There is a tendency of departments to try to downplay the problem because it is overwhelming to think about how to resolve it," said Bruce Lanphear, an epidemiologist and professor of health sciences at Simon Fraser University in Vancouver, British Columbia.
Lanphear reviewed the testing results from the EPA's most recent study in Chicago and said it is troubling that lead levels in some samples stayed high for multiple tests. Homeowners were instructed to take 12 one-liter samples in a row after not using water in their home for at least six hours. It would take about a minute and a half to three minutes for 12 liters to flow from a faucet, depending on water pressure and plumbing.
Eight homes in the study had five or more water samples that tested above 15 parts per billion for lead. One of those homes had 10 samples in a row with high lead levels. Yet that home, and all others tested, would have been considered safe under current federal guidelines because the first water samples came in under the action limit.
Miguel Del Toral, regulations manager for the EPA's Region 5 Ground Water and Drinking Water Branch, stresses that testing by EPA and utility officials is meant to mimic the worst-case scenario for lead exposure.
"You aren't getting that in every glass of water," he said.
Taking a shower, for example, could clear standing water from pipes coming into a house because a large amount of water is used. However, someone making a bottle for a baby with water from a kitchen faucet with separate pipes could still be using water with high lead levels. Running water for 30 or 45 seconds could reduce lead in that case, Del Toral said.
The EPA's testing shows that lead levels sometimes appeared to decrease the longer water was run. But three homes still had levels above 15 parts per billion on the 12th and last sample. The EPA would not release the location of the homes in Chicago.
Consumers often try to reduce their risk of lead by buying water filters, but most popular refrigerator pitchers, like Brita and PUR, don't filter out enough lead to meet the industry filtering standard. Many filters that connect to faucets or are installed under a sink do meet the standard but are less popular.
The testing that water utilities carry out is meant to gauge how corrosive water is as it flows through pipes. The more corrosive the water, the more it is going to cause lead to leach from pipes, solder and other plumbing materials.
Treatment plants add orthophosphate and other chemicals to water, which causes a white coating to form on the inside of pipes that is meant to stop lead from leaching into the water. But it isn't always effective.
One of the biggest challenges in testing for lead in water is accounting for variables. Water from two homes on the same block could have widely different lead levels, depending on the service lines that connect water mains to homes, the brass fittings that link pipes inside the home and repair work.
Del Toral said EPA officials know that lead is coming from lead service lines, but officials are also analyzing water samples to look for other sources, such as old galvanized pipes inside a home or brass faucets that can leach lead.
Some of the homes with high lead levels have had lead service lines "disturbed" in some way, meaning the pipe was rattled when street work was done or when a pipe was repaired. Such movement can cause protective coating inside a pipe to flake into water, adding lead because the coating already had pulled lead out of water. Once the coating flakes off, exposed pipe could also leach lead.
Testing done by Chicago's water department adds another wrinkle to the mystery of high lead levels in some homes. The city tested water in 24 homes, using different methodology than the EPA, and found that only one of 24 had a water sample with more than 15 parts per billion. The city took a first-draw sample and then more samples after one, three and five minutes.
When asked about the discrepancy in high lead levels found by the EPA and the low levels found by the city, water department Commissioner Thomas Powers said more testing needs to be done.
"This is an evolving study and is something that needs to be looked at," he said.
Del Toral said the EPA will continue to study the Chicago results and do another round of testing this month.
In addition to concern about testing methods, some public health experts are worried that the mark of 15 parts per billion isn't safe, as it was never meant to be a health-based standard. The limit, set in the 1990s, was based on a limit utilities could meet, taking cost into consideration. Many experts think it is too high, especially for infants, children and pregnant women.
The goal for lead in water is to get as close to zero as possible, said Jeffrey Griffiths, a physician who is chairman of a drinking water advisory board for the EPA and a professor of public health and medicine at Tufts University School of Medicine.
"The law is written so (15 parts per billion) is where you take action, but that doesn't mean that it is good," he said. "You'll still see adverse effects at lower levels."