No one knows more about the risks and challenges of dealing with lead in drinking water than Marc Edwards. The Virginia Tech civil engineering professor not only helped hold a spotlight up to Flint, Michigan’s water crisis, but years earlier he investigated a public health disaster in Washington D.C. that ended with Congressional hearings in 2010.
Edwards says the challenges around lead in water begin with reliable lead testing because lead is often occurs in particulate form.
“Back, say 10 years ago, we used to think that lead was dissolved in water like sugar or salt. And if it’s dissolved there are many (testing) techniques you can use,” Edwards says.
But he discovered particulates start to flake off as plumbing degrades, creating a health risk. “And it creates a nightmare because it’s random…That means you can take 100 samples from a house looking for lead and in one of those samples you could have a massive hazardous exposure, and all the rest could be nondetectable (amounts of lead).”
That information has turned testing upside down.
Edwards says for the last 25 years, “we used to tell people of they take one sample and it was low, their water is safe. We now know that is not true. It doesn’t mean the next glass of water your child drinks won’t elevate their blood-lead from zero to above lead poisoning standards.”
Edwards says the limitations of testing for lead in water, make filters look more and more attractive. “Because the filters can eliminate the risk from these particles and they are cheaper than analyzing the water.”
He says researchers and public health officials are now debating how to best take care of the problem.
Edwards says lead particles do not only break loose when crews are working on a water main, or replacing old lead service lines. "As [the pipe] rusts and gets old, chunks of lead can fall off here and not there, and you have this random release.”
As long as lead is present in the plumbing system, a potential hazard exists, he says.
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