Drinking Water: Safeguarding the District of Columbia's Supplies and Applying Lessons Learned to Other Systems
Published: 2004-07-22T00:00:00

Fast Facts:

Highlights:
section_title: Why GAO Did This Study
paragraphs: Concerns have been raised about lead in District of Columbia drinking water and how those charged with ensuring the safety of this water have carried out their responsibilities. The 1991 Lead and Copper Rule (LCR) requires water systems to protect drinking water from lead by, among other things, chemically treating it to reduce its corrosiveness and by monitoring tap water samples for evidence of lead corrosion. If enough samples show corrosion, water systems officials are required to notify and educate the public on lead health risks and undertake additional efforts. The Washington Aqueduct, owned and operated by the U.S. Army Corps of Engineers, treats and sells water to the District of Columbia Water and Sewer Authority (WASA), which delivers water to D.C. residents. EPA's Philadelphia Office is charged with overseeing these agencies. GAO is examining (1) the current structure and level of coordination among key government entities that implement the Safe Drinking Water Act's regulations for lead in the District of Columbia, (2) how other drinking water systems conducted public notification and outreach, (3) the availability of data necessary to determine which adult and child populations are at greatest risk of exposure to elevated lead levels, and what information WASA is gathering to help track their health, and (4) the state of research on the health effects of lead exposure. The testimony discusses preliminary results of GAO's work. GAO will report in full at a later date.
section_title: What GAO Found
paragraphs: This statement discusses GAO's preliminary observations and highlights areas of further examination. One of the key relationships in the effort to ensure the safety of the District's drinking water is the one between WASA, the deliverer of water, and EPA's Philadelphia Office, which oversees WASA's compliance with drinking water regulations. Recent public statements and corrective actions by these parties clearly indicate that coordination and communication between them could have been better in the years preceding the current lead controversy. GAO's future work will examine (to the extent appropriate) the interrelationships among other key agencies (such as the Aqueduct and the D.C. Department of Health); how other water systems in similar situations interacted with federal, state, and local agencies; and what the experiences of these other jurisdictions may suggest concerning how improved coordination can better protect drinking water in the District of Columbia. Other water systems facing elevated lead levels used public notification and education practices that may offer lessons for conducting outreach to water customers. For example, some of the practices of the two water systems we have begun to examine--the Massachusetts Water Resources Authority and the Portland (Oregon) Water Bureau--include tailoring their communications to varied audiences in their service areas, testing the effectiveness of their communication materials, and linking demographic and infrastructure data to identify populations at greatest risk from lead in drinking water. WASA faces challenges in collecting the information needed to identify District citizens at greatest risk from lead in drinking water. Specifically, WASA has partial information on which of its customers have lead service lines, and is in the process of obtaining more complete information. GAO's future work will examine the efforts of other water systems to go one step further by linking data on at-risk populations (such as pregnant mothers, infants, and small children) with data on homes suspected of being served by lead service pipes and other plumbing fixtures that may leach lead into drinking water. Nationally, much is known about the hazards of lead once in the body and how lead from paint, soil, and dust enter the body, but little research has been done to determine actual lead exposure from drinking water, and the information that does exist is dated. In our future work, we will examine the plans of EPA and other organizations to fill this key information gap.

section_title: Letter
paragraphs: Thank you for the opportunity to discuss our work to date on the issues  surrounding elevated levels of lead in Washington, D.C. drinking water. At  the request of this Subcommittee, we are examining issues concerning  lead in drinking water generally and the situation in Washington, D.C., in  particular. Our testimony today lays out our preliminary observations on  these issues and highlights areas of further examination.
Although rarely the sole cause of lead poisoning, lead in drinking water  can significantly increase a person’s total lead exposure. EPA estimates  that drinking water is the source of about 20 percent of Americans’ lead  exposure, but that it may be as high as 60 percent for infants who drink  baby formulas and concentrated juices that are mixed with water. Adults  who drink water with high lead concentrations could develop kidney  problems or high blood pressure. Developing fetuses, infants and young  children are more vulnerable to lead from all sources, including drinking  water. Their exposure to lead may delay their physical or mental  development.
The delivery of safe water to residents requires that water systems and  regulators work cooperatively in fulfilling the requirements of the Safe  Drinking Water Act. In most cases, states have primary oversight and  enforcement authority under the Act. Lead in drinking water is regulated  under the Act’s 1991 Lead and Copper Rule. The rule requires water  systems to treat their water to limit its corrosiveness, monitor tap water  samples for evidence of elevated levels of lead, and report this information  to their state. In addition, drinking water systems may consult with state  health agencies when communicating with their customers about health  risks from drinking water.
The relationship between regulators and water systems is more  complicated in the District of Columbia, where the Washington Aqueduct,  owned by the U.S. Army Corps of Engineers, draws and treats water from  the Potomac River. The Aqueduct sells the treated water to the District of  Columbia Water and Sewer Authority (WASA), which distributes it to  District residents. The Environmental Protection Agency’s (EPA)  Region III Office in Philadelphia, Pennsylvania, has primary oversight and  enforcement authority for the District’s public water systems. The District  of Columbia’s Department of Health, while having no formal role under  the Safe Drinking Water Act, is responsible for educating District residents  on potential health risks.
In the District, the Washington Aqueduct treats drinking water and  monitors for most contaminants, while WASA monitors tap water samples  for lead and reports these results to EPA’s Philadelphia Office. Tap water  monitoring is important because, unlike most drinking water  contaminants, lead is not generally introduced to drinking water supplies  from source water. Rather, lead leaches into drinking water as it travels  through lead service pipes, over pipe joints connected with lead-based  solder, and through brass plumbing fixtures that contain lead. According  to EPA, its Philadelphia Office is responsible for providing technical  assistance to the Aqueduct and WASA on how to comply with federal  regulations; ensuring that they report the monitoring results to EPA by  required deadlines; taking enforcement actions if violations occur; and  using those enforcement actions to return the water systems to  compliance in a timely fashion.
Significant concerns were raised in early 2004 about how federal and local  agencies were carrying out their responsibilities under the Safe Drinking  Water Act. At that time, the local media reported that a number of tap  water samples showed elevated levels of lead.
You asked that we (1) examine the current structure and level of  coordination among key government entities that implement the Safe  Drinking Water Act’s regulations for lead in the District of Columbia, and  identify any improvements to increase efficiency and accountability, (2)  determine how other drinking water systems that exceeded the EPA  action level for lead have conducted public notification and outreach, (3)  assess the availability of data necessary to determine which adult and  child populations are at greatest risk of exposure to elevated lead levels,  and what information WASA is gathering to help track their health, (4)  evaluate the state of research on lead exposure, and how this information  could help inform other drinking water utilities of potential problems in  their systems.
To respond to these questions, we are interviewing key officials and staff  with the federal and local agencies responsible for managing drinking  water and monitoring health for lead exposure in Washington, D.C.,  including officials at EPA’s headquarters and in its Philadelphia Office,  WASA, the Washington Aqueduct, and the D.C. Department of Health. We  are also (1) reviewing records documenting key activities and interactions  among these agencies, and examining their current responses to the lead  problem, (2) contacting academic and non-governmental experts in lead  contamination, and (3) examining how other water systems facing similar  circumstances notified and educated their customers on lead health risks,  and how they interacted with federal, state, and local agencies to respond  to the problem. Many of the facts and circumstances surrounding the  District’s lead controversy are the subject of active litigation. Accordingly,  we do not take a position on these issues and on how they bear on the  question of interagency coordination and communication, and instead  report them only as stated by the affected parties.
We are here to present our preliminary observations on these issues. We  will report our final findings and any recommendations we may develop at  a later date. In summary:    Providing safe drinking water requires that water systems, regulators, and  public health agencies fulfill individual roles, yet work together in a  coordinated fashion. It is particularly important that these entities report  and communicate information to each other in a timely and accurate  manner. Recent public statements and corrective actions by the  responsible entities, particularly EPA and WASA, clearly indicate that  coordination could have been better in the years preceding the current  controversy. As our work continues, we will seek to examine (to the  extent appropriate) specific ways in which improved coordination  between EPA and WASA could help both agencies better fulfill their  responsibilities. We will also examine interrelationships among other key  agencies (such as the Aqueduct and the D.C. Department of Health); how  other water systems in similar situations interacted with federal, state, and  local agencies; and what the experiences of these other jurisdictions may  suggest concerning how improved coordination can better protect  drinking water in the District of Columbia.
Other water systems facing elevated lead levels used public notification  and education practices that appear to offer lessons for conducting  outreach to water customers, including those in the District of Columbia.  For example, some of the practices of the two systems we have begun to  examine—the Massachusetts Water Resources Authority and the Portland  Water Bureau—include tailoring their communications to varied  audiences in their service areas, testing the effectiveness of their  communication materials, and linking demographic and infrastructure  data to identify populations at greatest risk from lead in drinking water.
WASA faces challenges in collecting the information needed to identify  District citizens at greatest risk from lead in drinking water. Specifically, it  has partial information on which of its customers have lead service pipes,  although it is currently in the process of obtaining more complete  information. In our future work, we will examine the efforts of other water  systems to go one step further by linking data on at-risk populations (such  as pregnant mothers, infants, and small children) with data on homes  suspected of being served by lead service pipes and other plumbing  fixtures that may leach lead into drinking water.
Much is known about the hazards of lead in the human body and about  how lead from paint, soil, and dust enter the body. However, little research  has been done to determine actual lead exposure from drinking water, and  the information that does exist is dated. In our future work, we will  examine the plans of EPA and other organizations to fill this key  information gap.
subsections: section_title: Background
paragraphs: Lead is unusual among drinking water contaminants in that it seldom  occurs naturally in source water supplies like rivers and lakes. Rather,  lead enters drinking water primarily as a result of the corrosion of  materials containing lead in the water distribution system and in  household plumbing. These materials include lead service pipes that  connect a house to the water main, household lead-based solder used to  join copper pipe, and brass plumbing fixtures such as faucets.
The Safe Drinking Water Act is the key federal law protecting public water  supplies from harmful contaminants. The Act established a federal-state  arrangement in which states may be delegated primary implementation  and enforcement authority (“primacy”) for the drinking water program.  Except for Wyoming and the District of Columbia, all states and territories  have received primacy. For contaminants that are known or anticipated to  occur in public water systems and that the EPA Administrator determines  may have an adverse impact on health, the Act requires EPA to set a non- enforceable maximum contaminant level goal (MCLG) at which no known  or anticipated adverse health effects occur and that allows an adequate  margin of safety. Once the MCLG is established, EPA sets an enforceable  standard for water as it leaves the treatment plant, the maximum  contaminant level (MCL). The MCL generally must be set as close to the  MCLG as is “feasible” using the best technology or other means available,  taking costs into consideration.
The fact that lead contamination occurs after water leaves the treatment  plant has complicated efforts to regulate it in the same way as most  contaminants. In 1975, EPA set an interim MCL for lead at 50 parts per  billion (ppb), but did not require sampling of tap water to show  compliance with the standard. Rather, the standard had to be met at the  water system before the water was distributed. The 1986 amendments to  the Act directed EPA to issue a new lead regulation, and in 1991, EPA  adopted the Lead and Copper Rule.
Instead of an MCL, the rule established an “action level” of 15 ppb for lead  in drinking water, and required that water systems take steps to limit the  corrosiveness of their water. Under the rule, the action level is exceeded if  lead levels are higher than 15 ppb in over 10 percent of tap water samples  taken. Large systems, including WASA, generally must take at least 100 tap  water samples in a 6-month monitoring period. Large systems that do not  exceed the action level or that maintain optimal corrosion control for two  consecutive 6-month periods may reduce the number of sampling sites to  50 sites and reduce collection frequency to once per year. If a water  system exceeds the action level, other regulatory requirements are  triggered. The water system must intensify tap water sampling, take  additional actions to control corrosion, and educate the public about steps  they should take to protect themselves from lead exposure. If the problem  is not abated, the water system must annually replace 7 percent of the lead  service lines under its ownership.
The public notification requirements of the Safe Drinking Water Act are  intended to protect public health, build trust with consumers through open  and honest sharing of information, and establish an ongoing, positive  relationship with the community. While public notification provisions  were included in the original Act, concerns have been raised for many  years about the way public water systems notify the public regarding  health threats posed by contaminated drinking water. In 1992, for  example, we reported, among other things, that (1) there were high rates  of noncompliance among water systems with the public notification  regulations in effect at that time and (2) notices often did not clearly  convey the appropriate information to the public concerning the health  risks associated with a violation and the preventive action to be taken.  The 1996 Amendments to the Safe Drinking Water Act attempted to  address many of these concerns by requiring that consumers of public  water supplies be given more accurate and timely information about  violations and that this information be in a form that is more  understandable and useful.
Drinking water is provided to District of Columbia residents under a  unique organizational structure:    The U.S. Army Corps of Engineers’ Washington Aqueduct draws water  from the Potomac River and filters and chemically treats it to meet EPA  specifications. The Aqueduct produces drinking water for approximately 1  million citizens living, working, or visiting in the District of Columbia,  Arlington County, Virginia, and the City of Falls Church, Virginia. Managed  by the Corps of Engineers’ Baltimore District, the Aqueduct is a federally  owned and operated public water supply agency that produces an average  of 180 million gallons of water per day at two treatment plants located in  the District. All funding for operations, maintenance, and capital  improvements comes from revenue generated by selling drinking water to  the District of Columbia, Arlington County, Virginia, and the City of Falls  Church, Virginia.
The District of Columbia Water and Sewer Authority buys its drinking  water from the Aqueduct. WASA distributes drinking water through 1,300  miles of water mains under the streets of the District to individual homes  and buildings, as well as to several federal facilities directly across the  Potomac River in Virginia. From its inception in 1938 until 1996, WASA’s  predecessor, the District of Columbia Water and Sewer Utility  Administration, was a part of the District’s government. In 1996, WASA  was established by District of Columbia law as a semiautonomous regional  entity. WASA develops its own budget, which is incorporated into the  District’s budget and then forwarded to Congress. All funding for  operations, improvements, and debt financing come from usage fees, EPA  grants, and the sale of revenue bonds.
EPA’s Philadelphia Regional Office has primary oversight and  enforcement responsibility for public water systems in the District.
According to EPA, the Regional Office’s oversight and enforcement  responsibilities include providing technical assistance to the water  suppliers on how to comply with federal regulations; ensuring that the  suppliers report the monitoring results to EPA by the required deadlines;  taking enforcement actions if violations occur; and using those  enforcement actions to return the system to compliance in a timely  fashion.
The District’s Department of Health, while having no formal role under  the Act, is responsible for identifying health risks and educating the public  on those risks.
section_title: Coordination Among Agencies Is Critical To Ensure Safe Drinking Water
paragraphs: Providing safe drinking water requires that water systems, regulators, and  public health agencies fulfill individual responsibilities yet work together  in a coordinated fashion. It is particularly important that these entities  report and communicate information to each other in a timely and  accurate manner. In the case of drinking water in the District of Columbia,  one of the key relationships is the one between WASA, the deliverer of  water to District customers, and EPA’s Philadelphia Office, the regulator  charged with overseeing WASA’s compliance with drinking water  regulations. Of particular note, one of WASA’s key obligations is to  monitor the water it supplies to District customers through a tap water  sampling program, and to report these results accurately and in a timely  manner to EPA’s Philadelphia Office. As EPA itself has noted, one of the  Philadelphia Office’s key obligations is to ensure that WASA understands  the reporting requirements and reports monitoring results by required  deadlines.
It is noteworthy that WASA and EPA have taken or agreed to take steps  that are clearly intended to improve communication and coordination  between the agencies. For example:    Under the Consent Order signed by EPA and WASA on June 17, 2004,  WASA agreed to improve its format for reporting tap water samples by  ensuring that the reports include tap water sample identification numbers,  sample date and location, lead and copper concentration, service line  materials, and reasons for any deviation from previously sampled  locations. The monitoring reports are also to include the laboratory data  sheets, which contain the raw test data recorded directly by the  laboratory. Under the Order, WASA also agreed to submit to EPA for  comment a plan and schedule for enhanced information, database  management, and reporting. The plan is to describe how monitoring  reports will be generated, maintained, and submitted to EPA in a timely  fashion.
EPA’s Philadelphia Office has altered the way in which it will handle  compliance data from WASA and the Washington Aqueduct. According to  the office, compliance data from both water systems will now be sent to  those in the Office responsible for enforcing the Safe Drinking Water Act,  so as to separate the enforcement/compliance assurance function from the  municipal assistance function.
Aside from the tap water monitoring issue, EPA’s Philadelphia Office  acknowledges that its oversight of WASA public notification and education  efforts could have been better, noting that “In hindsight, EPA should have  asked more questions about the extent, coverage and impact of DC  WASA’s public education program, and reacted to fill the public education  gaps where they were evident.” To address the problem, the Philadelphia  Office reported on its website that it will have to make some  improvements in the way it exercises its own oversight responsibilities.  Suggested improvements include obtaining written agreement from WASA  to receive drafts of education materials and a timeline for their  submission, reviewing drafts of public education materials for compliance  with requirements, as well as effectiveness of materials and delivery, and  acquiring outside expertise to assist in evaluating outreach efforts.
As our work continues, we will seek to examine (to the extent it does not  conflict with active litigation) other ways in which improved coordination  between WASA and EPA could help both agencies better fulfill their  responsibilities. We will also examine interrelationships that include other  key agencies, such as the Aqueduct and the D.C. Department of Health. We  will also examine how other water systems in similar situations interacted  with federal, state, and local agencies. These experiences may offer  suggestions on how coordination can be improved among the agencies  responsible for protecting drinking water in the District of Columbia.
section_title: Experiences of Other Water Systems Highlight Effective Ways to Inform and Educate the Public
paragraphs: WASA is not the first system to exceed the action level for lead. According  to EPA, when the first round of monitoring results was completed for large  water systems in 1991 pursuant to the Lead and Copper Rule, 130 of the  660 systems serving populations over 50,000 exceeded the action level for  lead. EPA data show that since the monitoring period ending in 2000, 27  such systems have exceeded the action level. As part of our work, we will  be examining the innovative approaches some of these systems have used  to notify and educate their customers. I would like to touch on the  activities of two such systems, the Massachusetts Water Resources  Authority and the Portland, Oregon, Water Bureau. Each of these systems  has employed effective notification practices in recent years that may  provide insights into how WASA, and other water systems, could improve  their own practices.
subsections: section_title: Massachusetts Water Resources Authority
paragraphs: The Massachusetts Water Resources Authority (MWRA) is the wholesale  water provider for approximately 2.3 million customers, mostly in the  metropolitan Boston area. Under an agreement with the Massachusetts  Department of Environmental Protection, monitoring for lead under the  Lead and Copper Rule occurs in each of the communities that MWRA  serves and the results are submitted together. Initial system-wide tap  water monitoring results in 1992 showed a 90th percentile lead  concentration of 71 ppb (meaning 10 percent of its samples scored at this  level and above). According to MWRA, adjustments in corrosion control  have led to a reduction in lead levels, but the 90th percentile lead  concentration in MWRA’s service area has still been above the action level  in four of the seven sampling events since early 2000.
According to an MWRA official, the public education program for lead in  drinking water is designed to ensure that all potentially affected parties  within MWRA’s service area receive information about lead in drinking  water. He noted, for example, that while the Lead and Copper Rule  requires that information be sent to consumers in their water bills, the  large population of renters living in MWRA’s service area often do not  receive water bills. Therefore, MWRA included information about lead in  its consumer confidence report, which is sent to all mailing addresses  within the service area. Additionally, MWRA uses public service  announcements, interviews on radio and television talk shows,  appearances at city councils and other local government agency meetings,  and articles in local newspapers to convey information. MWRA also  conducted focus groups to judge the effectiveness of the public education  program and continually makes changes to refine the information about  lead in drinking water.
An MWRA official also noted that MWRA focuses portions of its lead  public education program on the populations most vulnerable to the  health effects of lead exposure. For example, MWRA worked with officials  from the Massachusetts Women, Infants and Children Supplemental  Nutrition Program (WIC) to design a brochure to help parents understand  how to protect their children from lead in drinking water. Among other  things, the brochure includes the pertinent information in several foreign  languages, including Spanish, Portuguese, and Vietnamese. The WIC  program also includes information on how to avoid lead hazards when  preparing formula.
section_title: Portland Water Bureau
paragraphs: The Portland Water Bureau provides drinking water to approximately  787,000 people in the Portland metropolitan area, nearly one-fourth of the  population of Oregon. Since 1997, the city has exceeded the lead action  level 6 times in 14 rounds of monitoring. According to Bureau officials, the  problem stems mainly from lead solder used to join copper plumbing and  from lead in home faucets. Portland’s system has never had lead service  lines, and the Water Bureau finished removing all lead fittings within the  water system’s control in 1998.
The Portland Water Bureau sought flexibility in complying with the Lead  and Copper Rule. The state of Oregon allowed the Water Bureau to  implement a lead hazard reduction program as a substitute for the optimal  corrosion control treatment requirement of the Lead and Copper Rule.  Portland’s lead hazard reduction program is a partnership between the  Portland Water Bureau, the Multnomah County and Oregon State health  departments, and community groups. According to Portland Water Bureau  officials, the program consists of four components: (1) water treatment for  corrosion control; (2) free water testing to identify customers who may be  at significant risk from elevated lead levels in drinking water; (3) a home  lead hazard reduction program to prevent children from being exposed to  lead from lead-based paint, dust, and other sources; and (4) education on  how to prevent lead exposure targeted to those at greatest risk from  exposure.
As the components suggest, the program is focused on reducing exposure  to lead through all exposure pathways, not just through drinking water.  For example, the Water Bureau provides funding to the Multnomah  County Health Department’s LeadLine—a phone hotline that residents can  call to get information about all types of lead hazards. Callers can get  information about how to flush their plumbing to reduce their lead  exposure and can request a lead sampling kit to determine the lead  concentration in the drinking water in their home. The Water Bureau also  provides funding for lead education materials provided to new parents in  hospitals, for billboards and movie advertisements targeted to  neighborhoods with older housing stock, and to the Community Alliance  of Tenants to educate renters on potential lead hazards. Each of these  materials directs people to call the LeadLine if they need additional  information about any lead hazard. The Water Bureau evaluates the results  of the program by tracking the number of calls to the LeadLine, and by  surveying program participants to determine their satisfaction with the  program and the extent to which the program changed their behavior.
In January 2004, the Portland Water Bureau sent a targeted mailing to  those residents most likely to be affected by lead in drinking water. The  mailing targeted homes of an age most likely to contain lead-leaching  solder where a child 6 years old or younger lived. Approximately 2,600  postcards were sent that encouraged residents to get their water tested for  lead, learn about childhood blood lead screening, and reduce lead hazards  in their homes. Water Bureau officials said that they obtained the  information needed to target the mailing from a commercial marketing  company, and that the commercial information was inexpensive and easy  to obtain.
section_title: WASA Faces Challenges in Identifying At-Risk Populations
paragraphs: In an ideal world, a water utility such as WASA would have several  different types of information that would allow it to monitor the health of  individuals most susceptible to the health effects of lead in drinking water.  The utility would know the location of all lead service lines and homes  with leaded plumbing (pipes, solder and/or fixtures) within its service  area. The utility would also know the demographics of the residents of  each of these homes. With this information, the utility could identify each  pregnant woman or child six years old or younger who would be most  likely to be exposed to lead through drinking water. These individuals  could then be educated about how to avoid lead exposure, and lead  exposure for each of these individuals could then be monitored through  water testing and blood lead testing.
Unfortunately, WASA and other drinking water utilities do not operate in  an ideal world. WASA does have some information on the location of lead  service lines within its distribution area. Its predecessor developed an  inventory of lead service lines in its distribution system in 1990 as part of  an effort to identify sampling locations to comply with the Lead and  Copper Rule. According to WASA officials, identifying the locations of lead  service lines was difficult because many of the records were nearly 100  years old and some of the information was incomplete. According to this  1990 inventory, there were approximately 22,000 lead service lines. WASA  updated the inventory in September 2003, and estimated that it had 23,071  “known or suspected” lead service lines. WASA subsequently identified an  additional 27,495 service lines in the distribution system made of  “unknown” materials. Consequently, there is some uncertainty over the  actual number and location of the lead service lines in WASA’s distribution  system. The administrative order that EPA issued in June 2004 requires  WASA to further update its inventory of lead service lines.
Regardless of the information WASA has about the location of lead service  lines, according to WASA officials, WASA has little information about the  location of customers who are particularly vulnerable to the effects of  lead. The District’s Department of Health is responsible for monitoring  blood lead levels for children in the District. Officials from the Department  of Health told us that they maintain a database of the results of all  childhood blood lead testing in the District, and have studied the  distribution of blood lead levels in children on a neighborhood basis.  However, according to a joint study by the D.C. Department of Health and  the Centers for Disease Control and Prevention (CDC) published in March  2004, it is difficult to discern any effect of lead in drinking water on  children’s blood lead levels because the older homes most likely to have  lead service lines are also those most likely to have other lead hazards,  such as lead in paint and dust. This joint study also described efforts by  the Department of Health and the United States Public Health Service to  conduct blood lead monitoring for residents of homes whose drinking  water test indicated a lead concentration greater than 300 ppb. None of the  201 residents tested were found to have blood lead levels exceeding the  levels of concern for adults or children, as appropriate.
section_title: Researchers Face Gaps in Knowledge Regarding the Risks Posed by Lead in Drinking Water
paragraphs: A good deal of research has been conducted on the health effects of lead,  in particular on the effects associated with certain pathways of  contamination, such as ingestion of leaded paint and inhalation of leaded  dust. In contrast, the most relevant studies on the isolated health effects of  lead in drinking water date back nearly 20 years—including the Glasgow  Duplicate Diet Study on lead levels in children upon which the Lead and  Copper Rule is partially based. According to recent medical literature and  the public health experts we contacted, the key uncertainties requiring  clarification include the incremental effects of lead-contaminated drinking  water on people whose blood lead levels are already elevated from other  sources of lead contamination and the potential health effects of exposure  to low levels of lead. As we continue our work, we will examine the plans  of EPA and other organizations to fill these and other key information  gaps.
Lead is a naturally occurring element that, according to numerous studies,  can be harmful to humans when ingested or inhaled, particularly to  pregnant and nursing women and children aged six or younger. In  children, for example, lead poisoning has been documented as causing  brain damage, mental retardation, behavioral problems, anemia, liver and  kidney damage, hearing loss, hyperactivity, and other physical and mental  problems. Exposure to lead may also be associated with diminished  school performance, reduced scores on standardized IQ tests,  schizophrenia, and delayed puberty.
Long-term exposure may also have serious effects on adults. Lead  ingestion accumulates in bones, where it may remain for decades.  However, stored lead can be mobilized during pregnancy and passed to  the fetus. Other health effects in adults that may be associated with lead  exposure include irritability, poor muscle coordination and nerve damage,  increased blood pressure, impaired hearing and vision, and reproductive  problems.
There are many sources of lead exposure besides drinking water,  including the ingestion of soil, paint chips and dust; inhalation of lead  particles in soil or dust in air; and ingestion of foods that contain lead from  soil or water. Extensive literature is available on the health impacts of lead  exposure, particularly from contaminated air and dust. CDC identified in a  December 2002 Morbidity and Mortality Weekly Report the sources of  lead exposure for adults and their potential health effects. In a September  2003 Morbidity and Mortality Weekly Report, CDC identified the most  prevalent sources of lead in the environment for children, and correlated  high blood lead levels in children with race, sex, and income bracket. The  surveys suggest that Hispanic and African-American children are at  highest risk for lead poisoning, as well as those individuals who are  recipients of Medicaid. Dust and soil contaminated by leaded paint were  documented as the major sources of lead exposure. Children and adults  living in housing built before 1950 are more likely to be exposed to lead  paint and dust and may therefore have higher blood lead levels.
Articles in numerous journals have reported on the physical and  neurological health effects on children of lead in paint, soil, and dust. The  New England Journal of Medicine published an article in April 2003 that  associated environmental lead exposure with decreased growth and  delayed puberty in girls. In 2000, the Journal of Public Health Medicine  examined the implications of lead-contaminated soil, its effect on produce,  and its potential health effects on consumers. Lead can also enter  children’s homes if other residents are employed in lead contaminated  workplaces. In 2000, Occupational Medicine found that children of  individuals exposed to lead in the workplace were at higher risk for  elevated blood lead levels. The EPA has aided in some similar research  through the use of its Integrated Exposure Uptake Biokinetic Model for  Lead in Children (IEUBK). This model predicts blood lead concentrations  for children exposed to different types of lead sources.
According to a number of public health experts, drinking water  contributes a relatively minor amount to overall lead exposure in  comparison to other sources. However, while lead in drinking water is  rarely thought to be the sole cause of lead poisoning, it can significantly  increase a person’s total lead exposure—particularly for infants who drink  baby formulas or concentrated juices that are mixed with water from  homes with lead service lines or plumbing systems. For children with high  levels of lead exposure from paint, soil, and dust, drinking water is thought  to contribute a much lower proportion of total exposure. For residents of  dwellings with lead solder or lead service lines, however, drinking water  could be the primary source of exposure. As exposure declines from  sources of lead other than drinking water, such as gasoline and soldered  food cans, drinking water will account for a larger proportion of total  intake. Thus, according to EPA, the total drinking water contribution to  overall lead levels may range from as little as 5 percent to more than 50  percent of a child’s total lead exposure.
Mr. Chairman, this completes my prepared statement. I would be happy to  respond to any questions you or other Members of this Subcommittee may  have at this time.
section_title: Contact and Acknowledgments
paragraphs: For further information, please contact John B. Stephenson at (202) 512- 3841. Individuals making key contributions to this testimony included  Steve Elstein, Samantha Gross, Karen Keegan, Jessica Marfurt, and Tim  Minelli.
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