How and why we need to get the lead out of our lives

Our love/hate relationship with lead is as old as history itself. The origin of "plumbing" comes from the Latin word for lead. But only in the 1970s did we realize the consequences of even low doses of the hazardous metal, and by then it was in our pipes, our paint and our fuel. Science correspondent Miles O’Brien examines the lasting health consequences.

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  • GWEN IFILL:

    Now the risks of lead exposure, particularly for children.

    After some debate, Congress appears poised to provide special aid to Flint, Michigan, and possibly other cities with lead in their water.

    Our science correspondent, Miles O'Brien, looks at why lead was used for so long in so many places, and the health concerns, part of our weekly series on the Leading Edge of science and technology.

    RICHARD TRETHEWEY, Plumber, "This Old House": My great-grandfather would be quite proud right now.

  • MILES O’BRIEN:

    But he also might be a little worried, because fourth-generation plumber Richard Trethewey is showing me the technique for molding, shaping and joining pipe made of lead.

    We met in the cellar of the latest renovation project for the venerable PBS series "This Old House." It's a 1909 arts and crafts home in Arlington, Massachusetts.

  • MAN:

    Let's get started by talking with Rich Trethewey, the plumber. Come on in.

  • MILES O’BRIEN:

    Trethewey has been part of this famous band of TV renovators since the show debuted in 1979.

  • RICHARD TRETHEWEY:

    So, in 1909, this was high living, because you had a basement laundry.

  • MILES O’BRIEN:

    He fired up a burner and put some lead in a pot to do some plumbing the old-fashioned way.

  • RICHARD TRETHEWEY:

    When this house was plumbed, that lead pot would've been going all day long.

  • MILES O’BRIEN:

    In those days, pipes were not mass-produced, but rather custom-tailored on the work site.

  • RICHARD TRETHEWEY:

    So, you could take sheets of lead and you could shape it into all sorts of things you need. You could shape it into a round pipe. The nice thing about it was, it was a relatively low melting point.

  • MILES O’BRIEN:

    Lead melts at about 620 degrees Fahrenheit, and it holds heat, so it's easy to mold, a lead pipe cinch.

    It is a work of art in a way.

  • RICHARD TRETHEWEY:

    I guess so. I guess so. It will kill you, but it's a work of art.

    (LAUGHTER)

  • MILES O’BRIEN:

    Yes. There is that little detail.

    Our love/hate relationship with the element lead is as old as history itself. The Romans used lead pipes to carry water from the aqueducts into their homes. In fact, the word plumbing comes from the Latin word for lead, plumbum. Even then, the Romans knew high exposure to lead was dangerous.

    The ancient physician Dioscorides once wrote: "Lead makes the mind give way."

    But, for centuries, no one knew the consequences of low doses of lead. That changed in the 1970s, thanks to this man. Pediatrician and child psychiatrist Herbert Needleman conducted a series of studies measuring lead in children's teeth.

    He published the first evidence that even relatively low lead exposure can reduce I.Q.s, shorten attention spans, delay language proficiency and cause behavioral problems.

  • DR. HERBERT NEEDLEMAN, Pediatrician:

    There is a broad consensus on the part of everybody, except the lead industry and its spokesmen, that lead is extremely toxic at extremely low doses.

  • MILES O’BRIEN:

    Up until the mid-20th century, lead was mined and manufactured for all kinds of things besides plumbing. Most notably, it was used for decades as an additive to gasoline and paint.

    In the bad old days, the average lead level in American children was high. In 1976, it was 15 micrograms per deciliter. But as lead was banned in consumer products, that number dropped precipitously. It is now about one microgram per deciliter, a decrease of more than 90 percent.

  • DAVID BELLINGER, Harvard Medical School:

    It's remarkable. It's a great public health achievement. But what we now know is that the job isn't finished.

  • MILES O’BRIEN:

    Epidemiologist David Bellinger is a professor of neurology at Harvard Medical School.

  • DAVID BELLINGER:

    In most places in the U.S., we use the children to tell us where the lead is. We wait for a child to be overexposed before there's investigation into that child's environment.

  • MILES O’BRIEN:

    Lead persists in the soil near busy highways or smelters, in old, flaking paint, and also in vintage plumbing still in use, as we discovered in Flint, Michigan.

  • DAVID BELLINGER:

    There are tremendous reservoirs of lead remaining in the environment as legacy of those past heavy uses. And those sources of lead, we can come in contact with remarkably easily.

  • MILES O’BRIEN:

    When lead gets in our system, it becomes an impostor. It is similar enough to calcium that our bodies get tricked, so cells seeking that essential element take on lead instead.

  • DAVID BELLINGER:

    It's really a global assault on multiple organ systems at multiple levels. It's just a really bad actor.

  • MILES O’BRIEN:

    Especially for children. They absorb more lead than adults and are much more likely to be harmed by it, because their brains are still in development.

  • DAVID BELLINGER:

    It introduces noise into the system, so the brain is not working as efficiently as it would in the absence of lead. The consensus now by multiple authoritative international bodies is, there is no safe level of lead.

  • MILES O’BRIEN:

    An estimated 10 million U.S. homes are still connected to the water main with an old lead pipe, usually buried under the front yard. It's bad, but it could be worse.

    Over time, other metals in the water interact with the lead, creating a barrier between the pipe and the water, so it can flow through without becoming contaminated with lead.

  • RICHARD TRETHEWEY:

    So you can see the layer, the coating on the inside right here. That's the dissolved oxygen. And where it's shiny is where it's going to leach. So, where I cut it, you can see it's leaching.

  • MILES O’BRIEN:

    To ensure that barrier is not washed away, municipalities usually add an anti-corrosive chemical to the water. In Flint, they stopped doing that when they changed water sources. The water gradually ate away the protective barrier.

  • RICHARD TRETHEWEY:

    It broke down that inner layer. So, here, it was perfectly encased, and all the lead wasn't going to leach.

    And now you change what happens inside with either chlorine or fluorides or some sort of change on the water chemistry, and now that inner coating is gone, and now it becomes really deadly.

  • MILES O’BRIEN:

    So, how would you know if your home was connected to the water main with lead pipes? Richard Trethewey says you need to find the where the service comes in and look for the distinctive gray color.

  • RICHARD TRETHEWEY:

    It's a soft, formable pipe, and you will really get — by eye, you will be able to tell it.

  • MILES O’BRIEN:

    If you see it, have your water tested right away.

    While the mineral liner might be enough to protect your water, the safest long-term solution is to get the lead out. Digging up and replacing it is neither cheap nor easy, but the alternative is a huge health risk to children that will persist for generations to come.

    Miles O'Brien, the "PBS NewsHour," Arlington, Massachusetts.

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