美国国家公共电台 NPR Where Lead Lurks And Why Even Small Amounts Matter（在线收听）

Where Lead Lurks And Why Even Small Amounts Matter

RENEE MONTAGNE, HOST:

Here's the latest on the lead in Flint, Michigan's water. It no longer rises to what the Environmental Protection Agency calls the action level. New water tests do show progress. But even as the city's water has dropped to barely below the level where the EPA urges action, there is still potential for dangerous lead levels in individual homes. NPR's Jessica Pupovac reports.

JESSICA PUPOVAC, BYLINE: To test water for lead, you have to send samples to a lab, like this one in Washington, D.C.. Tom Jacobus, the general manager of the Washington Aqueduct, says lately they've been overwhelmed.

TOM JACOBUS: Since the Flint concern was raised, we've had about 600 samples come to the lab.

PUPOVAC: He says that's about five times more than last year.

JACOBUS: But - I mean, this is a big story, and people are concerned.

PUPOVAC: Parents are concerned, teachers, public officials - they're all sending water off to labs. And when they get the results, they're comparing them against 15 parts per billion. That's the Environmental Protection Agency's action level. Results above that threshold are a red flag for water utilities, a sign that they might have a lead problem. In many cities, officials have assured parents when lead levels at schools are below that number. News outlets are repeating those assurances. In Youngstown, Ohio...

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UNIDENTIFIED WOMAN #1: They are below the federal maximum permitted, which is 15 parts per billion.

PUPOVAC: In Tacoma, Wash...

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UNIDENTIFIED MAN: Fifteen parts per billion...

PUPOVAC: And in Newark, N.J...

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UNIDENTIFIED WOMAN #2: Should not exceed 15 parts per billion...

PUPOVAC: But there's a problem because that EPA action level, 15 parts per billion, is not a measure of safety. It was never intended to be used that way.

JEFF COHEN: I think the 15 parts per billion's gotten a bit of mischaracterization.

PUPOVAC: Jeff Cohen helped develop the EPA's regulation to control lead in the water. It's called the Lead and Copper Rule. It went into effect in 1991. Here's how it works - water utilities have to take samples in a certain number of homes and test them for lead. They get to essentially toss out the worst 10 percent. If any of the remaining samples still have lead levels above that 15 parts per billion, it means they have a problem. They have to do something to fix it. That's why it's called an action level. But, says Cohen...

COHEN: It's an action level for water systems. In the home, it's a different story. Like for an individual homeowner, I wouldn't consider 15 parts per billion a safe level.

PUPOVAC: He said it's not based on medical research. Utilities came up with that number. It's just what they told the EPA they could manage.

COHEN: It was never designed to identify a safe level of lead in drinking water. The goal of the rule is zero lead in drinking water.

PUPOVAC: That's because no amount of lead is known to be safe. But with the amount of lead in the water distribution system, zero isn't realistic. Lead isn't like other contaminants. It isn't usually there when the water leaves the treatment plant. When there is lead in tap water, it tends to come from the pipes, most often the pipes at the very end of its journey connected to or inside the house. The main source of lead is usually the service line. That's what brings water from the utilities main under the street to the house. Millions of homes across the country have service lines made of pure lead.

YANNA LAMBRINIDOU: Having a lead service line in front of one's home is essentially like drawing your water through a lead straw.

PUPOVAC: Yanna Lambrinidou teaches in the civil and environmental engineering department at Virginia Tech. She's a leading advocate for zero lead.

LAMBRINIDOU: You'll drink your water. It will be fine, low levels, low levels. And then all of a sudden, you'll get a lead particle that has fallen out of your pipes.

PUPOVAC: Those particles can flake off whenever something jostles the pipes, like a heavy truck coming down the road. Lead can also seep into the water when that water just sits in the pipes for too long. Utilities use chemicals to slow the process down, but, says Lambrinidou...

LAMBRINIDOU: We can minimize. We can control it as much as possible, but we cannot prevent it entirely.

PUPOVAC: The EPA says it's working on revisions to the Lead and Copper Rule, but they haven't changed the action level since the rule was first introduced. The American Academy of Pediatrics recently called for tightening all federal regulations. They said the limits, quote, "create the illusion of safety."

BRUCE LANPHEAR: Virtually every standard for lead is based more on feasibility as opposed to the best science.

PUPOVAC: Dr. Bruce Lanphear was the lead author of that position paper. He says there's been a drastic decline in blood lead levels in recent decades.

LANPHEAR: And yet, even at these lower levels, what we're finding is evidence of toxicity, IQ deficits, increases in behavior problems like ADHD and conduct disorder.

PUPOVAC: That's for children. In adults, low-level lead exposure can lead to high blood pressure and kidney problems. There are no public disclosure requirements for lead service lines like there are for lead paint, so many people who are at risk have no idea. Kate Gilles in Washington, D.C., was one of those people.

Is now an OK time? Is it nap time?

KATE GILLES: It's great, yeah.

PUPOVAC: She has a master's degree in public health, and checked for lead in the paint. She said she thought she would have been notified about something like lead service lines.

GILLES: Or that it would be part of home inspection or in any number of places or that DC Water would have something on your bill that's, like, by the way, if you'd like your lead pipes replaced...

PUPOVAC: It turns out she's gone through two pregnancies in a home with lead service lines. But all of this was before the crisis in Flint and before she called and asked the local utility, DC Water.

GILLES: I feel silly for not checking into it, but I also feel really angry that there's nothing that flags it for homeowners.

PUPOVAC: After NPR inquired, DC Water published a full map of the known lead service lines in the city. But like most utilities, their inventory has gaps - more than 13,000 homes that may or may not have lead service lines. Lambrinidou, from Virginia Tech, says that's a problem because people need that information to take action.

LAMBRINIDOU: Anybody that has any portion of lead in their service line, they should take precautions.

PUPOVAC: She says that ultimately removing and replacing any lead is the best option, but not everyone can afford it.

LAMBRINIDOU: Alternatively, taking other precautions is a very good idea, and these can include using a lead-certified water filter or bottled water.

PUPOVAC: Kate Gilles asked DC Water for a testing kit.

GILLES: Dear Michael Gilles...

PUPOVAC: We were there when she got her results.

GILLES: So it says sample first draw lead level 0.7 and second draw 0.4.

PUPOVAC: Her lead levels were well under the EPA's action level, but she decided to have her service line replaced anyway. It cost $1,400. Jessica Pupovac, NPR News.

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MONTAGNE: And at npr.org, we have a tool to help you determine if there's a lead service line connected to your home. It's in English and Spanish.