Toxic legacy: Wash U researchers look for ways to keep lead out of drinking water
Dan Giammar collects something most people want to get rid of: lead pipes.
“This is just a great piece of lead pipe,” said Giammar, turning the smooth cylinder in his hands.
The Washington University professor of environmental engineering is testing ways to keep lead pipes from dissolving and leaching into drinking water. Using old pipes from across the country, Giammar’s lab is working to understand whether adding a non-toxic compound to drinking water could prevent lead release.
Water pipes were often made of lead until the 1940s, partly because it’s a soft material that’s easy to bend.
Lead pipes also last an average of 35 years — more than twice as long as iron.
But they also make us sick.
We now know lead pipes dissolve over time and contaminate drinking water, causing a multitude of health problems from reduced kidney function to premature birth.
Despite early warnings from medical professionals in the 1920s, lead pipes were installed in cities across the country until World War II.
For its part, the lead industry led a robust campaign to promote the use of lead in household goods, including a 1923 advertisement in National Geographic announcing “Lead helps to guard your health.”
St. Louis, like many cities, installed tens of thousands of lead service lines, which connect the water main to individual homes. Today, there are an estimated 50,000 lead service lines remaining in the city, but Giammar said this isn’t necessarily cause for alarm.
To keep lead from leaching into the water, the St. Louis Water Department adjusts the water pH.
“Our concentrations of lead in the water are among the lowest in the country,” he said. “The relatively high pH of our water and the hardness of the water — which is the calcium and magnesium, and the alkalinity — seem to be quite protective against lead release.”
Another option for controlling lead release is adding nontoxic corrosion inhibitors, such as orthophosphate, during water treatment.
This particular compound has a number of drawbacks, however.
Because orthophosphate is a nutrient, utilities must remove it before releasing wastewater into the environment. If unchecked, nutrient runoff can cause large-scale algal blooms in waterways, which kill fish and other wildlife.
Giammar’s lab at Wash U is now investigating an alternative compound for preventing lead-pipe corrosion, known as sodium silicate.
The compound, which is used in a variety of household and industrial products, can be irritating to the skin and eyes in large quantities, but is not toxic to humans.
Tucked in the back of his lab, Giammar has secured rows of old lead pipes from Buffalo, New York, and Providence, Rhode Island, to a tall metal rack.
Some of them look a little worse for wear.
“We actually start with old lead pipes that were dug out of the ground and sent to us from different utilities,” Giammar said. “I think our oldest one was installed in 1886. It was in service for about 130 years, and then it got dug up and sent here.”
Each lead pipe is hooked up to a small whirring pump that recirculates the water for 16 hours a day.
The water chemistry of every city — the pH, alkalinity, hardness and chlorine — is like a fingerprint.
For this experiment, it’s critical that the water running through the pipes is as close as possible to water from Buffalo and Providence.
“We’re not in Buffalo, so we make up what we call ‘artificial Buffalo water,’” Giammar said.
Then, once a week, they collect water samples and take them down to a windowless room in the basement to analyze their lead concentrations.
The big question remains: Will sodium silicate prevent lead from dissolving into the water? And, if so, how does it work?
For the answer, Giammar said, we’ll have to wait at least several months.
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