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June 26, 2002
Good morning. Madam Chairwoman and members of the Subcommittee. I am Bob Williams, Assistant Surgeon General, U.S. Public Health Service, and Director of the Division of Health Assessment and Consultation at the Agency for Toxic Substances and Disease Registry (ATSDR). Thank you for the opportunity to once again provide you and the Subcommittee with testimony on the activities of ATSDR within the Spring Valley community.
ATSDR, an agency of the U.S. Department of Health and Human Services, is the lead public health agency responsible for implementing the health-related provisions of the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). The mission of ATSDR is to serve the public by using the best science, taking responsive public health actions, and providing trusted health information to prevent harmful exposures and disease related to toxic substances.
ATSDR has been working with the area residents of Spring Valley, the Mayor's Spring Valley Scientific Advisory Panel, the Spring Valley Restoration Advisory Board, the D.C. Department of Health (DC DOH), the U.S. Environmental Protection Agency (EPA), and the U.S. Army Corps of Engineers to assess the public health impact of environmental contamination with hazardous substances.
In December 2000, testing conducted by the U.S. Army Corps of Engineers detected elevated concentrations of arsenic in soil samples collected from the playground of the Child Development Center at American University. Surface soil samples collected from the playground contained arsenic at an average concentration of 57 parts per million (ppm) and at a maximum concentration of 498 ppm. Parents of children who attended the Child Development Center expressed concern that their children may have been exposed to this contamination. In response to these concerns, the DC DOH asked ATSDR to assess potential exposures to arsenic-contaminated soil by children and staff there.
On February 1-2, 2001, ATSDR conducted an Exposure Investigation for children who were then enrolled at the center and for teachers and staff at the Child Development Center. ATSDR staff collected hair samples from 28 children and four adults and analyzed the samples for arsenic. At the time of this Exposure Investigation, the participants had been relocated from the contaminated playground area for over one month. Because of this interval, measuring hair arsenic levels was the only feasible test to assess whether exposure to arsenic had occurred in the window ending one month prior. Urine testing was not conducted because it is only useful if arsenic exposure has occurred in the previous few days.
Detectable levels of arsenic were measured in hair samples from eight of the 32 Exposure Investigation participants at concentrations that ranged from 0.10 to 0.14 ppm. All of the hair arsenic levels detected in the participants were within ranges reported for unexposed populations. In the other 24 hair samples, arsenic was not detected. ATSDR concluded that none of the participants had hair arsenic levels that indicated unusual exposure to arsenic. ATSDR sent the adult participants and the parents of minor participants their test results. In addition, ATSDR staff held a public availability session to meet with the parents to discuss their children's test results. The report for this Exposure Investigation and other ATSDR reports are available on the ATSDR web site at www.atsdr.cdc.gov/ofp/springvalley/index.html.
On November 13, 2001, ATSDR staff met with the Spring Valley Restoration Advisory Board to describe ATSDR activities in the Spring Valley community. The following day, ATSDR conducted a focus group session with some members of the Restoration Advisory Board. The purpose of the session was to gather community concerns and information that would assist ATSDR and the DC DOH to determine health education needs for the Spring Valley community. ATSDR has continued to gather community concerns through needs assessment surveys, electronic mail messages, and telephone contacts.
The U.S. Army Corps of Engineers has continued to characterize soil contamination in residential properties in potentially affected areas of Spring Valley. This testing has documented that arsenic levels in composite soil samples from residential areas range from background levels to a maximum of just over 200 ppm. Residents of Spring Valley have expressed concern over possible health effects from exposure to this contamination. In response to these concerns, the DC DOH asked ATSDR to evaluate potential exposure to arsenic in residents of contaminated properties.
In response to this request, ATSDR conducted a second Exposure Investigation. On December 7, 2001, ATSDR staff met with the Mayor's Spring Valley Scientific Advisory Panel to describe the proposal. On January 23, 2002, ATSDR held a public meeting and poster session at Sibley Hospital to discuss the Exposure Investigation with the community. ATSDR then conducted this second investigation during March 13-15, 2002.
Residents who lived at the 20 homes with the highest soil arsenic concentrations were invited to participate. A total of 32 people (23 adults and nine children) from 13 homes volunteered. ATSDR staff collected urine and hair samples from the participants, as well as house dust samples from their homes. The urine samples were analyzed for both inorganic forms of arsenic and total arsenic. These two, separate analyses for arsenic can help to distinguish between dietary sources of arsenic (primarily from fish and shellfish) and environmental sources of exposure. ATSDR provided the participants their individual test results and presented a summary of the findings to the Mayor's Spring Valley Scientific Advisory Panel on May 29, 2002.
Urine arsenic levels, which are a good measure of recent arsenic exposure, were generally low in the individuals tested. These levels would not be expected to cause any health problems. Only three of the individuals tested had reportable inorganic arsenic in their urine, with levels ranging from 10 parts per billion (ppb) to 15 ppb. Levels below 20 ppb of inorganic arsenic usually indicate no significant exposure.
The levels of total arsenic in urine samples from the participants ranged from non-detected to 210 ppb. Total urinary arsenic reflects exposure to inorganic arsenic plus organic forms of arsenic from foods such as fish and shellfish. Organic forms of arsenic are relatively non-toxic. It is not unusual to find total urinary arsenic in the general population at these levels.
Hair arsenic testing is not as accurate as urine testing but allows us to look at arsenic exposure during the past months (depending on the length of the hair). All individuals tested had hair arsenic levels between non-detected and 0.73 ppm. The average was 0.1 ppm. Levels below 1 ppm usually indicate no significant exposure. In summary, the hair arsenic levels show normal levels of exposure. These levels would not be expected to cause any health problems.
Household dust was tested in 13 homes. Levels of arsenic ranged from non-detected to 63 ppm. The household dust samples are used to indicate if arsenic contamination is found within a residence. The health significance of these values is not always clear because it depends on the opportunity for exposure. It is evident from the participants' hair and urine tests that these dust levels do not appear to be causing elevated inorganic arsenic levels in the participants. However, the findings do suggest that yard soil contaminated with arsenic may be tracked into homes and could increase the potential for exposures.
The report of the Exposure Investigation will undergo an additional scientific review, and ATSDR will release a detailed report of all of these findings later this year.
Ongoing ATSDR Activities Within the Spring Valley Community
In March 2001, ATSDR received a petition to conduct a Public Health Assessment for the Spring Valley site. The petition was submitted by a Pennsylvania law firm that is representing some people who live or work in Spring Valley. ATSDR accepted the petition in September 2001. Among other activities, ATSDR will prepare a Health Consultation in response to the petition request. The consultation will evaluate the health implications of arsenic contamination in soil in residential yards in Spring Valley. In addition, the consultation will discuss the relationship between exposure to site contaminants and health conditions (such as anemias) that are of concern to the residents. The consultation will also make recommendations for follow-up activities that are needed. ATSDR anticipates releasing a draft Health Consultation by the end of this year.
In January 2002, ATSDR mailed a newsletter that described ATSDR activities to over 1,000 Spring Valley residents. ATSDR will continue to send semiannual newsletters to update the community on ATSDR activities.
ATSDR is preparing a pamphlet to address health and safety issues that have been raised by home gardeners in the area. The pamphlet will be included with ATSDR's next newsletter.
ATSDR is preparing a packet of health education materials for physicians and other health care providers in the area. The packet will contain pertinent background information about Spring Valley and will discuss health issues that may be related to site contaminants.
ATSDR will continue to work with other Federal and local health and environmental agencies and the residents to resolve questions and issues relating to the public health impact of environmental contamination in Spring Valley. Further ATSDR involvement, including additional biomonitoring to assess exposure to site contaminants, will be decided after discussions with the Mayor's Spring Valley Scientific Advisory Panel, the Spring Valley Restoration Advisory Board, and the local community.
Madam Chairwoman, this concludes my testimony. I would be happy to answer any questions you or your fellow subcommittee members may have.
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Last revised: July 2, 2002