So Giammar proposed a second project for the Water Research Foundation just to study the lead +4 oxides. "They're fascinating solids," he says.
Then Giammar's lab picked up a third project. "A little over a year ago, I got a call from an environmental engineer in Washington, D.C., who was looking at something called galvanic corrosion and its potential to release lead into drinking water," he says.
This is the project that led to the centenarian lead pipe experiment now taking up much of the bench space in his lab.
Unlike some of the other water problems he has studied, galvanic corrosion is national in scope. The Environmental Protection Agency is concerned enough that it has appointed a science advisory board to make recommendations on how best to deal with it, Giammar says.
How low can we go?
It's difficult to talk about lead in a sensible way. The current threshold for drinking water is 15 micrograms per liter, Giammar says. And while there's talk in the community about lowering the allowable levels of some water contaminants, lead is not among them.
Environmental lead is ubiquitous and everyone has measurable levels of lead in their blood. We are exposed to it through dust and air as well as through water, thanks in part to the tetraethyl lead added to gasoline as an antiknock compound for 80 years.
"If your dominant exposure is through dust, there's little benefit to ratcheting down your exposure to water even further," Giammar says.
But, he says, because of the Lead and Copper Rule, water utilities now monitor lead levels. And he learned at a recent conference that during the most recent monitoring period, only 30 utilities had lead levels above the drinking water standard.
That may seem like a lot, he said, but there are roughly 54,000 water utilities in t
|Contact: Diana Lutz|
Washington University in St. Louis