Lead In D.C.’s Drinking Water

From 2001 to 2004, tens of thousands of people in Washington, D.C., unknowingly drank tap water that contained lead. The “D.C. lead-in-water crisis” was one of the most serious episodes of heavy-metal contamination of drinking water in modern U.S. history. Although officials working for D.C.’s water utility, the Washington Area Sewer Authority (WASA), the D.C. Department of Health (DC DOH), and the U.S. EPA knew about the problem, the public was in the dark. The contamination persisted for three years before the Washington Post informed D.C. residents about the situation in a story published in 2004. dc_lead.jpgThe news outraged parents who were worried about their children’s health, angered politicians who hadn’t been told, and created anxiety among public-health experts who initially feared a community-wide crisis. Children’s health was the focus of concern because lead’s effects on neurodevelopment are notorious—low levels of exposure can cause a long list of problems that include hyperactivity, decreased learning ability, and trouble paying attention. In the aftermath of the crisis, public-health experts, including scientists from the U.S. Centers for Disease Control & Prevention, examined blood lead data collected by DC DOH and water lead data collected by WASA and concluded that there had been little if any harm to the public. This “no harm” conclusion defied previous studies that showed that drinking water contaminated with high levels of lead can markedly raise children’s blood lead levels, and the results were very influential. But a study published today in Environmental Science & Technology (DOI: 10.1021/es802789w) reveals that hundreds of babies and toddlers in D.C. were affected by the contamination from 2001 to 2003. In babies under 16 months of age living all over the city, the contaminated tap water caused the incidence of elevated blood lead levels to increase by more than 400%. For toddlers, the substantial increases were largely confined to certain neighborhoods, where an unlucky combination of lead water pipes and highly contaminated tap water created the conditions for higher exposure. In these high-risk neighborhoods, the incidence of high blood lead levels among toddlers more than doubled in 2001 and remained high until 2004. “This new paper is important and very persuasive,” says Harvard Medical School pediatrician Michael Shannon, an expert in children’s lead exposure. “This is the first paper about the D.C. lead crisis to get it right. The authors really show quite convincingly that the lead in the drinking water resulted in lead poisoning in some children.” The paper’s coauthors, Virginia Tech environmental engineer Marc Edwards and Children’s National Medical Center pediatrician Dana Best, set out to determine the impact of the D.C. lead crisis by looking at the most vulnerable group—babies—living in the neighborhoods where the contamination was the greatest. The scientists accomplished their goal, but these results suggest many new questions as well as provide new answers. Most important, why did previous studies miss the effects? And what lessons does the D.C. lead crisis have for the rest of the nation? Image: JUPITERIMAGES Editor’s Note: Renner will explore the story behind the science of this paper in an upcoming ES&T news article.

Author: Rebecca Renner

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  1. This is a massive failure for which District health and water officials properly must shoulder substantial blame for being inept watchdogs (or worse), but isn’t it true that the US Army Corps of Engineers changed the chemistry of DC’s water supply? Why did the lead levels spike? No one says. Please address this issue.


    Read Scott Martin
    Capitol Hill

  2. My question- is anything being done about this? What about the children who have been effected? I have long suspected high lead levels in my son’s developmental delays.
    Someone needs to be held responsible!!

    Spring Valley

  3. You’re right that the Corps who manage the Washington Aqueduct changed the chemistry. On November 1, 2000, the Aqueduct changed its residual disinfectant from free chlorine to chloramines to lower disinfection byproducts produced when chlorine reacts with naturally occurring organic matter in the water. The residual disinfectant is what goes along with the water as it travels the distribution system i.e. after it leaves the Aqueduct. The switch was a big cause, but not the only reason for the lead spike.
    EPA Office of Water last year released a report on this. Here’s the link:
    Part of the problem was that DC water contained a lot of residual chlorine for many years — there had been microbial problems and the high levels of chlorine were to address that. The high levels of chlorine made the water highly oxidizing and fostered growth of mineral scales that contained PbO2. When the switch was made to chloramine, the oxidizing environment changed and the PbO2 scales were no longer stable.
    Rebecca Renner

  4. Hi Maria,

    The Post is reporting today that D.C. Council members asked the city’s inspector general yesterday to investigate whether public health agencies and the water utility “negligently or
    intentionally” misled the public during the District’s water crisis in 2004 and
    whether they should have looked harder for a correlation between high levels of
    lead in the water and health risks to children. Edwards, Triantafyllidou, and Best have done us all a service by doing the science to demonstrate the harm.
    Rebecca Renner

  5. There is another culprit in this scandal – the lead industry. By the early years of the 20th century, it had become quite clear that leaded pipes were the cause of many cases of lead poisoning, and many local water authorities had switched to iron pipes. The Lead Industries Association (LIA) — as indicated in their meeting minutes — reacted in the 1930s by sending its agents around the country to lobby and “educate” both local water authorities and master plumber
    organizations on the advantages of lead pipes.

    As a result of the LIA’s lobbying, which lasted into the 1950s, we now have to “get the lead out” at great cost.

    An article has recently been published in the American Journal of Public Health, “The Lead Industry and Lead Water Pipes: ‘A Modest Campaign.'” (http://www.ajph.org/cgi/content/abstract/98/9/1584)

  6. Hi Richard,
    I’d like to see those minutes and that article. Have you seen Werner Troesken’s book, The Great Lead Water Pipe Disaster? Troesken shows that after lead pipes were installed in the mid- to late- 1800s, there were observant doctors and scientists who figured out the harmful effects of the pipes. In regions with corrosive water supplies like Massachusetts and northern England he attributes the deaths and illnesses of millions of people — infant mortality rates and stillbirth rates increased by 25% — to the very high levels of lead that got into tap water. Given that there are still about 2 million lead service line water pipes underground and in use in the US it is a good thing that engineers have, in most cases, learned how to control the corrosivity of water.
    Rebecca Renner

  7. What did you make of CDC’s comment in today’s Washington Post that their 2004 MMWR study was “clearly” not scientific? If I’ve read this study correctly, it features 1) a longitudinal analysis of childhood blood lead levels in relation to year and service pipe material (lead vs. non-lead), and 2) a cross-sectional analysis of blood lead levels of residents living in homes with extremely high water lead levels. What about these analyses is not “scientific”? Moreover, if this study is “clearly” not scientific, what is it? Thanks, Yanna

  8. Hi Yanna,

    That’s a good question and I don’t know what Dr. Brown meant. A few months ago I interviewed the Director of CDC’s National Center for Environmental Health Dr. Howard Frumkin about the 2004 MMWR study and its strengths and weaknesses. He told me that CDC was working on a much more detailed analysis. He indicated that this more detailed work would substantiate the 2004 MMWR findings and he also defended the 2004 study and the data on which it is based.

    On Tuesday, January 27 in response to Edwards et al. Dr. Frumkin’s office sent this statement:

    “Lead poisoning among children is always a tragedy and is something CDC has worked very hard to prevent. Since our initial efforts in 2004, CDC has continued to work with DC health officials by continuing its data analysis on lead levels in DC during the period 1998-2006. The report of this work should be released later this year and will provide critical information that the city can use to help vulnerable children.

    CDC continues to emphasize that lead exposure is a hazard, especially for children, and that public health interventions should focus on eliminating all childhood lead exposures (the same conclusion reached in CDC’s 2004 MMWR report). The MMWR article clearly stated, “Because no threshold for adverse health effects in young children has been demonstrated, public health interventions should focus on eliminating all lead exposures in children.”

    CDC welcomes new research. Scientific investigation of a known health hazard such as lead, including work that clarifies routes of exposure and helps quantify exposure risks, is the foundation of sound public health action.”

  9. As the Obama administration takes over, are there signs that the CDC will handle lead issues differently? And on a micro level, can families protect themselves with commercial activated carbon water filters?



  10. Hi Slater,

    There has been a small sign that things are different now. Over at Science News, Janet Raloff reports that Marc Edwards has received a bit more cooperation from CDC since President Obama was sworn in. Here’s the link:

    You ask about lead issues across the nation. Right now the scientific consensus is that paint is the primary source of lead to children. This can be paint chips or dust and soil can be contaminated by paint or other sources. Water is not considered to be a significant source.

    There’s an interesting paper that came out last year by Levin et al (here’s the link)
    The paper acknowledged the importance of paint but also noted that water is an often ignored source. The authors of this paper all work for government agencies, including CDC.

    Here are the numbers: First the good news. Since 1975 the blood lead levels of children in the US have dropped due mostly to the elimination of lead in gasoline, house paint, and other products. In addition water companies have used chemical corrosion control to limit leaching of lead from existing lead water pipes. But lead is still a leading environmental poison for children. In 1999 an estimated 310,000 US children, or 1.6%, had blood lead levels greater than the CDC level of concern which is 10 micrograms/deciliter and 1.4 million, almost 14%, had levels between 5 and 9 micrograms/deciliter.

    The current system of investigating lead poisoning has a bias against water. When a child with elevated blood lead is identified, local public health authorities send in a team of inspectors. The inspectors use a portable XRF machine to look for lead paint, swipe floors, window sills and other hard surfaces. They very rarely sample the water. In Pennsylvania where I live, I went on a few home inspections and asked why the workers did not sample the water. They told me that the state lab would analyze the swipe samples for free, but if they wanted to do water they’d have to find a lab and pay for the analyses. They also told me that water wasn’t a problem even though they didn’t have evidence to say this.

    Now look at this. In almost a third of cases nationally, the source of a child’s elevated blood lead levels can not be traced to paint and the source is never found. In their paper Edwards, Triantafyllidou, and Best suggest that water might account for a sizable proportion of those mystery cases. It’s also worth noting that there are still some 2 million lead service line water pipes in use in the US.

    In addition to that consider this: take a house where there is a paint problem and a water problem. The inspectors find the paint and they stop right there. They never sample the water. So they miss the water.

    Meanwhile we know that water levels can exceed EPA standards and in some homes those exceedences could lead to elevated blood lead levels in kids. In 2004, 274 utilities serving 11.5 million people reported high lead levels in drinking water, according to a Washington Post investigation which found that many more water utilities withhold or manipulate test results to ward off regulators. In 2006 levels of lead in drinking water became very high in parts of Maine, Providence, R.I., Bristol, Conn. Cities that have long-standing problems with lead in tap water include: Boston, Lansing, Mich., and Portland, Ore.,

    There is also evidence from other parts of the country that lead in drinking water can cause lead poisoning in children. In 2006 public health workers traced the source of lead poisoning in a number to toddlers to drinking water. In one city, Greenville, NC. the water company didn’t have any lead pipes. What happened is that the water company changed the chemical it uses to make organic matter settle out of water at the reservoir. That chemical change made the water corrosive to solder that had been used in some people’s homes.

    So everyone acknowledges that paint is a very important source of lead to children. Now there are some scientists saying that water is a more important source than previously realized.

    You also asked about commercial activated carbon water filters. Any filter certified as removing lead by the National Sanitation Foundation will do the job. When it comes to replacing lead service lines, if a utility offers to replace part of the pipe and gives the homeowner the option of paying to replace the rest, it is a good investment to replace the rest. Emerging data show that partial replacements don’t always work to reduce lead levels at the tap.

  11. Thanks, Rebecca, for your responses to questions. They’re quite informative.

  12. I have been reading with interest and sadness regarding the recently published article on D C water contamination.I live in England where our pipe lines are in the main lead. A huge proportion of our houses would pre date1987 .Is there any evidence that the same problem is here in the U K ?

  13. Hi Shirley, This is a very good question. There is very strong evidence, from relatively recent studies in Glasgow and other areas, that old lead pipes are still a significant contributor to elevated blood lead.

    Here is one of the studies:
    Watt, G.C.M.; Britton, A.; Gilmour, H. G.; Moore, M. R.; Murray, G. D.; Robertson, S. J. Public health implications of new guidelines for lead in drinking water: A case study in an area with historically high water lead levels. Food Chem. Toxicol. 2000, 38, 73–79.


  14. We live near the DC reservoir. My neighborhood was developed in the late 1930s-1950s (my own home was built in 1937.) The city is currently replacing lead pipe lines down the street. My question is does the proximity to the water’s treatment (and maybe the potency of the chemicals in the water) increase the level of lead leaching if there is significant lead piping?

    Thank you for your sharing your knowledge of this subject. This research is very important to me as I have three children born between 2000-2004.

  15. Dear Lalie,

    I am very sorry that you are living through this uncertainty, worry and frustration — at least those are the emotions I would feel. I took the liberty of forwarding your question to environmental engineer Marc Edwards because I don’t know enough to answer this. Here is his reply:

    “We currently do not know how the distance from the treatment plant affected
    lead leaching in D.C. from 2001-2004, or from 2004-present for that matter. We
    will soon publish a paper that shows in some systems, the worst problems with
    chloramine arise furthest from the treatment plant. So if that applied to your
    situation, you would not be worse off, and perhaps even better off, than the
    rest of DC.”

  16. Hi Becky,

    I’m doing research on DC’s lead-in-water story and I’m having a hard time accessing two of your ES&T news articles that used to be online: one is Mis-Lead and the other is about the health effects of lead in DC water in 2001-2004 (it focuses on the risk assessments controversy). Do you know why? What’s the best way to obtain them again?



  17. Hi Yanna,

    I’ve just tried to look them up and I see what you mean. I’ll look into this and get back to you.

  18. Thanks so much Becky. I am in the middle of an e-mail exchange about lead in water with the DC government and I want to send them your Mis-Lead piece, because it addresses some of the issues we are discussing. It would be very nice if it were still accessible online, because it offers information with direct applicability to the situation in front of us right now. I look forward to hearing what you find out. Best, Yanna

  19. Hi Yanna,

    Sorry it took me a while to find out about this. The features and news should be free. Apparently when a new computer system was installed, it caused this glitch and it is being fixed (you can tell I don’t know much about this). I will ask to see if perhaps i could just post Mis-lead to this blog as an interim measure.

  20. If anyone doubts the damage that lead poisonong can cause, the recent finding that most of Beethoven’s maladies: bowel problems, deafness, behavioral problems, many other symptoms I am not qualified to report – were not symptons of a sexually transmitted disease, but LEAD POISONING! Evidently tests were performed recently on a sample of Beethoven’s hair to determine this. If it were my child in DC, I would demand to know why this water-crisis was kept from the public for three years. Whoever was responsible is akin to feeding poison to thousands of children.


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