Skip directly to search Skip directly to A to Z list Skip directly to navigation Skip directly to site content Skip directly to page options

Exposure Investigation
Spring Valley Neighborhood


(a.k.a. Spring Valley Chemical Munitions/American University)
Washington, DC
Cost Recovery # A175
June 28, 2002

Agency for Toxic Substances and Disease Registry
Division of Health Assessment and Consultation
Atlanta, GA 30333

Objective

This exposure investigation examines individuals in the Spring Valley neighborhood of Washington, DC for possible exposure to arsenic contamination in their yards. A total of 32 individuals were tested-23 adults and nine children (age 16 months to 13 years). These individuals live in 13 homes with elevated composite soil arsenic levels. Urine and hair arsenic levels were tested in these individuals, and household dust was analyzed for arsenic in each of the homes.

Background

During World War I, the U.S. Army conducted chemical warfare research in northwest Washington, DC at a site known as the American University Experimental Station. Chemical weapons were detonated at several locations during research and training operations. Lewisite and mustard gas were among the chemical warfare agents that were reportedly tested. Chemical agents-including hazardous substances, ordnance, and explosive waste-were buried in the area. The former test area has since been developed and is now occupied by the American University campus and residential homes which comprise the Spring Valley neighborhood.

In January 1993, a contractor digging a utility trench in Spring Valley uncovered buried ordnance. The U.S. Army Corps of Engineers (Corps) implemented Operation Safe Removal and removed 141 munitions that included suspected chemical munitions containing mustard gas and fuming sulfuric acid.

The Corps has reviewed historical records and has conducted extensive geophysical surveys with electromagnetic instruments to identify other potentially impacted areas. In addition, they have conducted soil sampling in potentially affected areas to characterize the extent and nature of chemical contamination. Discovery and remedial efforts are continuing in Spring Valley and related areas.

ATSDR Activities at Spring Valley

ATSDR has been working with the Department of the Army, Army Corps of Engineers, U.S. Environmental Protection Agency (EPA), DC Department of Health (DC DOH), American University, Spring Valley Science Advisory Panel, Spring Valley Restoration Advisory Board, and the residents to assess the public health impact of environmental contamination with hazardous substances.

Between June 1997 and the present, ATSDR has prepared five Health Consultations and one Technical Assistance document, which assessed soil contamination at the site. These consultations were conducted at the request of the DC DOH, the EPA, Region III, or the Corps.

In December 2000, contaminated soil was identified at the Child Developmental Center at the American University. Surface soil samples collected from the playground were contaminated with arsenic at an average concentration of 57 μg/g (ppm) and a maximum concentration of 498 μg/g (ppm) (ATSDR, March 28, 2001). ATSDR conducted an exposure investigation (hair analyses for arsenic) at the Child Developmental Center on February 1-2, 2001. Hair samples from 28 children and four adults did not indicate elevated arsenic exposure in children or workers at this Center, and the property has subsequently been remediated (ATSDR, March 8, 2001).

Other Site-Related Activities

On February 10 and 15, 2001, Washington Occupational Health Associates, Inc. (WOHA), collected hair and urine samples at American University. The target population for this exposure investigation included staff and students who attended the Center in the past 12 months, maintenance and grounds crew members, and athletes who play on the intramural fields. Sixty-six people (39 adults and 27 children) provided hair samples. Urine samples were provided by four adults. WOHA concluded that results of their exposure investigation indicated no elevated levels of arsenic in the population tested (WOHA, March 26, 2001).

The Corps has continued to characterize soil contamination in residential properties in potentially impacted 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 202 ppm. Residents of Spring Valley have expressed concern over possible health effects from exposure to this contamination. In response to these concerns, the DC Department of Health asked ATSDR to evaluate potential exposure to arsenic in residents of contaminated properties.

Rationale for an Exposure Investigation

In order to assess exposure to arsenic, ATSDR conducted testing of urine, hair, and household dust in houses with the highest levels of arsenic contamination in their yards. Results from this exposure investigation help us evaluate the potential for exposure of residents in the Spring Valley community to arsenic in soils.

Arsenic that is ingested is rapidly excreted from the body into the urine within a few days after exposure. Therefore, ATSDR analyzed urine samples for arsenic as an indicator of exposure to arsenic within the preceding few days. The urine samples were analyzed for total arsenic and speciated arsenic (inorganic arsenic, dimethyl arsenic acid, and methylarsonic acid). By conducting these two separate analyses, we can differentiate exposure to inorganic arsenic from exposure to less toxic forms of arsenic that occur in food such as fish and shellfish.

ATSDR also tested hair samples for arsenic content. The concentration of arsenic in the root of the hair is in equilibrium with the concentration of arsenic in the blood. Therefore, arsenic is deposited in the hair as it grows. By measuring the concentration of arsenic in a length of hair, we can obtain an integrated measure of arsenic exposure over the period of time the hair grew. Scalp hair grows at a rate of about 1 cm/month, so a 2-inch segment of hair represents about five months of growth.

Household dust was tested to determine if arsenic-containing soil is being tracked or blown into the house. There are no set standards for interpreting the health significance of household dust concentrations of arsenic. The major use of household dust results is to identify a possible pathway of exposure, and to investigate a possible source in households where individuals do have elevated urine or hair arsenic levels.

Methods

Target Population

Residents who lived at the 20 homes with the highest soil arsenic concentrations were invited to participate. The Army Corps of Engineers's composite soil sampling of residential yards was used to determine those homes. These soil values ranged from 62 ppm to 202 ppm arsenic. A total of 32 people (23 adults and nine children) from 13 homes volunteered to participate. ATSDR staff collected urine and hair samples from the participants, as well as house dust samples from their homes.

Consent/Confidentiality

Prior to testing, each resident and a parent or legal guardian of each minor participant was required to sign an informed consent/assent form. Sample copies of these forms are in Appendix C. In addition to completing a consent form, each family was asked a few questions regarding the family members' exposure history.

Individual test results and an explanation of their significance were provided to the participants in writing. An ATSDR physician was available to discuss individual results by phone and during a community visit at the local hospital. Recommendations for follow-up actions were made, if indicated. Individual test results were not made available to the public, and confidentiality was protected according to Federal and State laws.

Test Procedures

Urine testing:

ATSDR staff distributed urine specimen cups and instructions for sample collection to all participants in the exposure investigation. The participants were advised not to eat fish or shellfish for three days prior to donating a first-morning void urine sample.

The urine samples were sent to National Medical Services laboratories in Spring Willow, Pennsylvania. The samples were analyzed for total and speciated arsenic by graphite furnace atomic absorption spectroscopy and atomic fluorescence spectroscopy. Urine creatinine was also analyzed. Test results were reported as micrograms of arsenic per liter of urine (μ/L) and in micrograms of arsenic per gram of creatinine (μ/g creatinine).

Hair testing:

An ATSDR physician collected a hair sample from each individual who was able and willing to provide a 0.5 gram lock of hair. When possible, hair specimens were collected from the back of the head at the nape of the neck. Collection methods differed slightly depending on the length of hair. However, the entire length of hair was sent for analysis.

After collection, the hair samples were sent to the National Medical Services laboratories in Spring Willow, Pennsylvania. The samples were analyzed for total arsenic by graphite furnace atomic absorption spectroscopy. Test results were reported as micrograms of arsenic per gram of hair (μg/g). Reference ranges for concentrations of arsenic in hair from unexposed populations range from 0.02 to 1.0 μ/g. (National Medical Services, 2001)

Indoor Dust Sampling:

Sample collection was performed utilizing a Nilfisk GS-80 vacuum cleaner equipped with a high efficiency particulate air (HEPA) filter. Soil and other particulate matter embedded within the carpet are collected and returned to the laboratory for sieving and analysis. Sampling was from a square meter sampling area at the front entry door and another area at the rear entry door of the home.

Results

Results for urine, hair, and dust samples are available in Table 1 (see Appendix 1). In general, the values showed arsenic exposure at low levels.

All individuals tested had total urinary arsenic between 3.5 μ/L and 210 μ/L. The detection level was 1.0 μ/L. The average (mean) was 23.5 μ/L. Only three of the individuals tested had reportable levels of inorganic arsenic in their urine, with levels of 10 μ/L, 12 μ/L, and 15 μ/L. Reportable levels were equal to or above 10 μ/L. The creatinine corrected values for these three individuals were 2.7 μ/g, 7.1 μ/g, and 8.3 μ/g respectively.

All individuals tested had hair arsenic levels between non-detectable and 0.73 μ/g. The average (mean using ½ detection level for non-detectable) was 0.1 μ/g.

Household dust was tested in 13 homes. Levels of arsenic ranged from non-detectable to 63 μ/g of dust. The average (mean using ½ detection level for non-detectable) was 9.9 μ/g of dust.

Discussion

Arsenic can be measured in urine, hair, or blood to evaluate exposure. Measurement of arsenic in blood is not a reliable indicator of chronic exposure to low levels of arsenic since it is cleared from the blood within a few hours and reflects only very recent exposure. Blood arsenic levels are also difficult to interpret since the relationship between levels of exposure and blood concentrations has not been well established. (National Research Council, 1999)

Urine arsenic is the most reliable method for measuring arsenic exposure, particularly exposures occurring within a few days of the specimen collection. Although a 24-hour urine collection is considered an optimal sample due to fluctuations in excretion rates, most exposure studies have used a first morning void or a random sample due to ease of collection. The first morning void urine results have correlated well with 24-hour results. Speciated urinary arsenic is preferable to total urinary arsenic since the speciated forms can distinguish between exposure to inorganic arsenic and its metabolites and the relatively non-toxic forms of organic arsenic commonly found in seafood.

Individuals in this exposure investigation had their urine tested for total arsenic (which could come from all sources--food, water, air, soil and dust) and for inorganic arsenic (which might be coming from contaminated soil and dust). The total urinary arsenic is mostly organic arsenic from food sources, which is much less toxic than inorganic arsenic.

In summary, the urine arsenic levels in this exposure investigation show low levels of exposure. These levels would not be expected to cause any health problems. Only three of the individuals tested had reportable inorganic arsenic (levels of 10 μg/L or higher) in their urine, with levels of 10 μg/L, 12 μg/L, and 15 μg/L. These values all decreased when corrected for creatinine to standardize the urine concentration. The creatinine corrected values for these three individuals were 2.7 μg/g , 7.1 μg/g, and 8.3 μg/g respectively. All three individuals with inorganic arsenic in their urine were adults.

All individuals tested had total urinary arsenic between 3.5 μg/L and 210 μg/L. The detection level was 1.0 μg/L. The average (mean) was 23.5 μg/L. It is common to find total urine arsenic in the general population at these levels.

It is not clear whether the small elevations of inorganic arsenic in the three individuals are related to soil or dust arsenic contamination. Dietary arsenic is mostly organic arsenic, but does contain a small percentage of inorganic arsenic. The individual with the highest total arsenic level of 210 μg/L had consumed seafood in the three days prior to testing. It is not unusual that the inorganic arsenic would be slightly elevated from the dietary arsenic alone.

The individual with a total arsenic level of 94 μg/L and an inorganic arsenic level of 15 μg/L probably represents the most exposed individual in this exposure investigation. It is notable that this individual's household dust level was also the highest in the investigation. Health effects are not expected in an adult with these urine levels, however, two caveats should be kept in mind: 1) These levels may not represent the maximum exposure to this individual over the course of a year, and 2) It is prudent public health practice to encourage this individual to decrease exposures both inside and outside the home.

Measurement of arsenic in hair can be used to evaluate potential exposures occurring during the time of hair growth, since a small amount is incorporated into the hair as it grows. Theoretically, this could determine exposures occurring over several months depending on the length of the hair. However, external arsenic found in water and dust particles can adsorb strongly to the hair surface and are not easily washed off even by laboratory methods. Thus, it is difficult to distinguish whether arsenic measured in hair samples is the result of internal absorption or toxicologically insignificant deposition of dust on the hair surface. Nevertheless, measuring hair arsenic levels may be of some value. A hair arsenic level in the normal range indicates that unusual exposure has not occurred. However, if the hair arsenic level is elevated, it is not possible to unequivocally determine whether the person has been exposed to arsenic, or whether the arsenic is just external contamination.

Hair arsenic testing is not as unequivocal as urine testing, but allows us to look at arsenic exposure during the past months or years (depending on the length of the hair). All individuals tested had hair arsenic levels between non-detectable and 0.73 μg/g. The average (mean using ½ detection level for non-detectable) was 0.1 μg/g. The detection level was 0.03 μg/g hair. Levels below 1 μg/g hair usually indicate no significant exposure. In summary, the hair arsenic levels show low 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-detectable to 63 μg/g of dust. The average (mean using ½ detection level for non-detectable) was 9.9 μg/g of dust. The detection limit ranged from 0.6 μg/g dust to 3 μg/g dust, depending on the mass of the sample. 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.

Conclusions

1) Urine and hair arsenic testing show low levels of arsenic exposure in this population.

2) These levels would not be expected to cause health problems.

3) Small amounts of arsenic are present in the dust of some homes in the Spring Valley neighborhood.

4) It is not clear whether the small elevations of inorganic arsenic in the three individuals are related to soil or dust arsenic contamination, or represent dietary intake of arsenic.

Recommendations

1) Continuation of plans by the ACOE to remediate yards with elevated soil arsenic levels.

2) Thorough and consistent cleaning of homes by residents (using safe cleaning techniques such as wet mopping vs. vacuuming) with an emphasis on decreasing the amount of tracked-in soil from the yard.

3) Careful attention to using practices and techniques which decrease inhalation and ingestion of soil particles while working in the yard and garden.

References

ATSDR; Toxicological Profile for Arsenic (Update); September 2000.

ATSDR; Health Consultation: Exposure Investigation, Spring Valley Chemical Munitions (a/k/a American University Child Development Center), Washington, District of Columbia, DC, March 8, 2001.

ATSDR; "Report assessing public health implications of arsenic in soils at the American University Child Development Center", March 28, 2001.

Kalman, D.A. and others. The Effect of Variable Environmental Arsenic Contamination on Urinary Concentrations of Arsenic Species. Environmental Health Perspectives, Vol. 89, pp. 145-151, 1990.

National Research Council (NRC). Arsenic in Drinking Water. Washington, DC: National Academy Press, 1999.

National Medical Services, Product Services Manual, 2001.

Washington Occupational Health Associates, Inc. Health Consultation: Arsenic Exposure Investigation at American University, Washington, DC, March 26, 2001.

Table 1. Arsenic Levels in Urine, Hair, and Household Dust

House Household dust arsenic,
front entrance/
rear entrance
(μg/g dust)
Family
member
Total
Urine Arsenic
(μg/L)
Inorganic
Arsenic in
urine
(μg/L)
Inorganic
Arsenic in
urine
(μg/g
creatinine)
Hair
Arsenic
(μg/g)
1 2.5/2.5 A 24 NR NR 0.07
    B -- -- -- 0.12
    C 6.7 NR NR NA
2 13/8 A 12 NR NR 0.15
    B 9.2 NR NR ND
    C 15 NR NR NA
    D 14 NR NR 0.73
3 4.3/5.8 A 13 NR NR 0.16
    B 14 NR NR 0.4
4 15/34 A * * * 0.09
    B * * * 0.08
    C * * * 0.08
    D 12 NR NR 0.21
5 4/7.1 A 18 NR NR 0.05
    B 45 NR NR 0.05
    C 210 10 2.7 NA
    D 15 NR NR 0.11
6 6.2/5.7 A 18 NR NR 0.09
    B 13 NR NR 0.05
7 14/nd A 26 12 7.1 NA
    B 7.4 NR NR ND
8 6.9/4.7 A 10 NR NR ND
    B 15 NR NR NA
9 8/3.6 A 3.5 NR NR 0.09
    B 5.7 NR NR 0.07
10 6.6/8 A 9.3 NR NR NA
11 4.2/8.4 A 11 NR NR 0.12
12 5.5/63 A 94 15 8.3 NA
13 3.7/13 A 25 NR NR ND
    B 5.7 NR NR 0.1
    C 5.4 NR NR ND
    D 2.4 NR NR ND
* Specimen lost in handling
NR = non-reportable (<10μg/L)
NA = hair specimen not available
ND = non-detectable (below detection limit)


(Participant Consent for Specimen Testing)

An exposure investigation is being conducted to determine if you were exposed to arsenic.

The Washington, DC Department of Health and the Agency for Toxic Substances and Disease Registry (ATSDR) is offering free voluntary urine and hair testing for arsenic exposure for residents with elevated levels of arsenic in the soil of your yard. Along with the free testing, exposure information will be collected with a brief questionnaire. Participation in this investigation will enable you to know your own levels of arsenic and will enable the local agencies to identify if public health actions are needed to reduce exposure.

Benefits

I understand that I will benefit from participating by learning whether I (or my child/ward) have had elevated exposures to arsenic. If elevated exposure has occurred, I will receive information on how to reduce current and future exposure. Written information about arsenic exposure will be available to me and to my physician, if I identify him or her in the questionnaire.

Procedure/Tests:

Urine - A representative of the Washington DC Department of Health will distribute urine specimen cups and instructions to all participants during the week prior to the exposure investigation. The participants will bring the first urine they make on the morning of the exposure investigation in a urine specimen with them to the exposure investigation site.

Hair - An ATSDR physician will cut a hair sample of about 0.5 grams from the back of the head (nape of the neck) of you or your child using a pair of scissors. This lock of hair is equal to a bundle of hair about as thick as a pencil. This should not cause you or your child any pain. This hair sample will be tested only for arsenic.

Participation

I understand that my participation is voluntary. Furnishing any information is voluntary and even if I agree to participate and sign this form, I can stop my participation or my child's/ward's participation at any time without penalty or loss of benefits. I understand and agree that there is no provision for compensation or medical treatment offered by ATSDR based upon the test results or in the event of injury from participation. I understand that I must sign this form to participate.

Results

I understand every effort will be made to provide the results of my tests in writing to me within approximately 2 months. However, unforeseen circumstances may delay the date. Results that are of immediate health concern will be reported to me as soon as they are known. I will receive an actual test result in addition to laboratory reference values with an explanation of their significance. If my results reveal an elevated value of arsenic, I understand that I should notify my personal physician.

Confidentiality

Confidentiality will be protected to the fullest extent possible according to state and federal laws. Any reports produced from this information will give only group information and not identify specific individuals. I understand that if I participate in a confidential manner, any forms containing my name or address will be kept in locked cabinets at ATSDR and the Washington, DC Department of Health. Test results may be released only to other federal, state, and local public health (and environmental) agencies, if permitted by me. I understand if I want my results sent to my physician, I must provide the contact information and my signature authorizing a release of this information.

Contact

If I have any additional questions about this investigation or the testing, I may contact: Dr. Robert Johnson of ATSDR at 1 (888) 422-8737.

Consent

The risks and benefits of this exposure investigation have been explained to me. All of my questions have been satisfactorily answered. I hereby freely and voluntarily give my signed consent for participating in the testing described above.

I, (print)_____________________________, the undersigned, agree to urine and hair sampling and completing questionnaires for:

(___) Myself

I, (print)_____________________________, the undersigned, agree to urine and hair sampling and completing questionnaires for:

(___) Myself

(___) My child/ward, ______________________, age -___

(___) My child/ward, ______________________, age -___

(___) My child/ward, ______________________, age -___

(___) My child/ward, ______________________, age -___

Signature: ____________________________________________ Date: ________________

Signature: ____________________________________________ Date: ________________

Address: ____________________________________________

____________________________________________

____________________________________________

Phone #: _____________________

Witness: _____________________ _____________________

(print name) (signature)


Assent Form for Children
(7- 17 years of age)

A statement to be read to children in the presence of the parent/guardian:

"We want to find out if you have been exposed to arsenic. Arsenic is something which you cannot see but may cause illness. To know if you have arsenic in your body, we would like to take a sample of the urine you provided, and a small sample of hair from the back of your neck. It is considered very safe, and your mother/father/guardian has said that it would be all right for you to do this."

"Do you have any questions? May we take a sample of your urine and hair?"

The above information has been read to me and I want to participate.

Name of Child: _______________ Signature of Child:____________________Age____

Name of Child: _______________ Signature of Child:____________________Age____

Name of Child: _______________ Signature of Child:____________________Age____

Name of Child: _______________ Signature of Child:____________________Age ___

Name of Child: _______________ Signature of Child:____________________Age____

Date: ______________

Witness: _____________________ _____________________

(print name) (signature)


Agency for Toxic Substances and Disease Registry
U.S. Department of Health and Human Services
Atlanta, Georgia 30333
Consent to Access to Property
Spring Valley Exposure Investigation

The Agency for Toxic Substances and Disease Registry (ATSDR) of the U.S. Department of Health and Human Services is conducting an exposure investigation. Participation in this investigation is voluntary. Your participation in this investigation will help to measure possible concentrations of arsenic in your home.

This investigation involves collecting indoor dust on your property. The samples will be analyzed for arsenic. The dust will be collected by vacuuming a small area of your flooring.

Participation

Furnishing any information is voluntary and you may choose to stop participation at any time, even after signing this consent form. If you choose not to participate, or to stop at any time, there will be no penalty or loss of benefits.

Results

Every effort will be made to provide the sampling results to you by mail within 2 months after the collection period has ended. A summary of all results will also be interpreted and made available to the community and the local department of health.

If you have any questions please contact:

Robert Johnson, MD
Agency for Toxic Substances and Disease Registry
1 (888) 422-8737

Directions: If you do not understand the description of this portion of the exposure investigation, please ask questions. If you agree to participate, please sign the consent form below.

CONSENT FOR ACCESS TO PROPERTY

Name:_____________________________________

Address:_____________________________________

____________________________________________

I hereby consent to employees of the Agency for Toxic Substances and Disease Registry (ATSDR) and parties authorized by ATSDR, entering and having continued reasonable access to the above described property for the collection of dust/soil samples.

I am the property owner, or an individual having the authorization of the property owner to make this access agreement.

This written permission is given by me voluntarily with full knowledge of my right to refuse and without threats or promises of any kind.

Signature Date

Witness:

Print name Signature


BRIEF ARSENIC EXPOSURE QUESTIONNAIRE

Name:____________________________________

Have you eaten seafood in the past 3 days? Y N

Do you smoke? Y N

Do you have contact with the soil in your yard (gardening, yard work, etc.)? Y N

Have you recently used any pesticides or garden sprays? Y N

Have you eaten any vegetables grown in your garden? Y N

Have you worked with chemically-treated (for example, CCA) wood? Y N

Do you have pets which spend time outdoors? Y N

What is your current occupation?__________________________________


ATTACHMENT B

Exposure Investigation Protocol

Spring Valley Neighborhood

Exposure Investigation Protocol

Spring Valley Neighborhood

Washington, DC

February 19, 2002

Agency for Toxic Substances and Disease Registry

Division of Health Assessment and Consultation

Summary

During World War I, the U.S. Army conducted chemical warfare research at the site of the present Spring Valley neighborhood in Washington, DC Chemical weapons were detonated in several areas during research and training operations. Chemical agents and weapons were also buried in the same area. The area has since been developed, and it is now occupied by residential homes and the American University.

In December 2000, contaminated soil was identified at the Child Developmental Center (CDC) at the American University. Surface soil samples collected from the playground were contaminated with arsenic at an average concentration of 57 μg/g (ppm) and a maximum concentration of 498 μg/g (ppm) (ATSDR, March 28, 2001). ATSDR conducted an exposure investigation (hair analyses for arsenic) at the CDC on February 1-2, 2001. Hair samples from 28 children and 4 adults did not indicate elevated arsenic exposure in children or workers at this Center, and the property has subsequently been remediated (ATSDR, March 8, 2001).

On February 10 and 15, 2001, Washington Occupational Health Associates, Inc. (WOHA), collected hair and urine samples at American University. The target population for this exposure investigation included staff and students who attended the Center in the past 12 months, maintenance and grounds crew members, and athletes who play on the intramural fields. Sixty-six people (39 adults and 27 children) provided hair samples. Urine samples were provided by 4 adults. WOHA concluded that results of their exposure investigation indicated no elevated levels of arsenic in the population tested (WOHA, March 26, 2001).

Ongoing testing of residential soils in the Spring Valley neighborhood have shown composite soil levels ranging from background to around 202μg/g (ppm). Residents of Spring Valley have expressed concern over possible exposures to arsenic they may have received during activities at their homes. To test for possible exposures, ATSDR, in conjunction with the Washington DC Department of Health, will collect urine and hair samples from local residents and test the samples for arsenic.

This investigation is being done to determine the extent of a community health problem and to develop plans for its control. Results from this exposure investigation will be used to evaluate the potential for exposure of residents in the Spring Valley community to arsenic in soils.

Rationale

In order to assess exposure to arsenic, ATSDR will conduct indoor dust sampling and biological monitoring of potentially exposed residents. Arsenic that is ingested is rapidly excreted from the body into the urine within a few days after exposure. Therefore, ATSDR will analyze urine samples for arsenic as an indicator of exposure to arsenic within the past few days. The urine samples will be analyzed for total arsenic and speciated arsenic (inorganic arsenic, dimethyl arsenic acid, and methylarsonic acid). By conducting these two separate analyses, we will be able to differentiate exposure to inorganic arsenic from exposure to less toxic forms of arsenic that occur naturally in fish and shellfish.

ATSDR will also test hair samples for arsenic content. The concentration of arsenic in the root of the hair is in equilibrium with the concentration of arsenic in the blood. Therefore, arsenic is deposited in the hair as it grows. By measuring the concentration of arsenic in a length of hair, one can obtain an integrated measure of arsenic exposure over the period of time the hair grew. Scalp hair grows at a rate of about 1 cm/month, so a 2 inch segment of hair represents about 5 months of growth.

Target Population

Biological and indoor dust testing for arsenic will be offered to residents of the 10 homes with the highest residential soil arsenic levels in soil, and who have had some soil contact (for example, gardening, landscaping, playing in the yard) in the past six months. The Army Corps of Engineers's composite soil sampling of residential yards will be used to determine those 10 homes.

Consent/Assent Form

Prior to testing, each resident and a parent or legal guardian of each minor participant will be required to sign an informed consent/assent form. A copy of these forms is in Appendix A.

Test Procedures

Arsenic can be measured in urine, hair, or blood to evaluate exposure. Measurement of arsenic in blood is not a reliable indicator of chronic exposure to low levels of arsenic since it is cleared from the blood within a few hours and reflects only very recent exposure. Blood arsenic levels are also difficult to interpret since the relationship between levels of exposure and blood concentrations has not been well-established.

Urine arsenic is the most reliable method for measuring arsenic exposure, particularly exposures occurring within a few days of the specimen collection. Although a 24-hour urine collection is considered an optimal sample due to fluctuations in excretion rates, most exposure studies have used a first morning void or random sample due to ease of collection. Under steady state exposure conditions, as would be assumed for most residents of this community, random or spot urine results have correlated well with 24-hour results. Speciated urinary arsenic is preferable to total urinary arsenic since the speciated forms can distinguish between exposure to inorganic arsenic and its metabolites and the relatively non-toxic forms of organic arsenic commonly found in seafood.

Measurement of arsenic in hair can be used to evaluate potential exposures occurring during the time of hair growth, since a small amount is incorporated into the hair as it grows. Theoretically, this could determine exposures occurring over several months depending on the length of the hair. However, external arsenic such as dust particles, can adsorb strongly to the hair surface and are not easily washed off even by laboratory methods. Thus, it is difficult to distinguish whether arsenic measured in hair samples is the result of internal absorption or toxicologically insignificant deposition of dust on the hair surface. Nevertheless, measuring hair arsenic levels may be of some value. A hair arsenic level in the normal range indicates that unusual exposure has not occurred. However, if the hair arsenic level is elevated, it is not possible to unequivocally determine whether the person has been exposed to arsenic, or whether the arsenic is just external contamination.

Urine testing:

ATSDR staff will distribute urine specimen cups and instructions for sample collection to all participants in the exposure investigation. The participants will be advised not to eat fish or shellfish for 3 days prior to donating a first-morning void urine sample.

The urine samples will be sent by overnight mail to National Medical Services laboratories in Spring Willow, Pennsylvania. The sample will be analyzed for total and speciated arsenic by graphite furnace atomic absorption spectroscopy and atomic fluorescence spectroscopy. Urine creatinine will also be analyzed. Test results will be reported as micrograms of arsenic per liter of urine (g/L) and in micrograms of arsenic per gram of creatinine (μg/g creatinine). Inorganic urinary arsenic in unexposed individuals is normally < 20 g/L. Total arsenic levels below 100 μg/g creatinine are expected for individuals without occupational or dietary exposures. (Kalman, 1990)

Hair testing:

A representative of ATSDR will collect a hair sample of approximately 0.5 grams from each individual as described by the following protocol which was provided by the contract laboratory (National Medical Services). When possible, hair specimens will be collected from the back of the head at the nape of the neck. Collection methods will differ slightly depending on the length of hair.

To collect hair at least 2 inches long:

Step 1: The person collecting the donor's hair should wash their hands thoroughly with soap and water.

Step 2: Remove the alcohol wipe packet and the white capped bottle labeled Hair Collection Container from the resealable plastic bag. This bottle contains the hair collection tube, which has been split down its length.

Step 3: Find an appropriate spot on the back of the head for hair collection. The metal clip may be useful to partition the hair from the hair to be tested. Tightly twist a bundle of hair, making sure that it is approximately 1/4 inch in diameter.

Step 4: While holding the tightly twisted bundle of hair in one hand, spread open the hair collection tube with the other hand, then enclose the hair bundle with this tube as close to the donor's scalp as possible. The twisted hair bundle should be thick enough to completely fill the hair collection tube.

Step 5: Clean the scissor blades with the alcohol wipe. Cut the twisted hair bundle as close to the scalp as possible. Use extreme care not to injure the donor. Do not remove the collection tube from the cut hair. Tie twist tie tightly around the root end.

Step 6: Place the hair with the collection tube and twist tie in the Hair Collection Container provided and label.

Step 7: Place Hair Collection Container with the donor's hair back into the plastic bag and reseal it.

To collect hair samples less than 2 inches long:

Step 1: The person collecting the donor's hair should wash their hands thoroughly with soap and water.

Step 2: Remove the alcohol wipe packet and the small hair collection vial.

Step 3: Clean scissor blades with the alcohol wipe. Using extreme care not to injure the donor, cut hair as close to the scalp as possible. Place the cut hairs in the small screw capped vial provided. Attempt to fill this vial with loosely packed hairs.

Step 4: Seal the small vial, label, and place in the plastic bag and reseal.

After collection, the hair samples will be sent by overnight mail to the National Medical Services laboratories in Spring Willow, Pennsylvania. The sample will be analyzed for total arsenic by graphite furnace atomic absorption spectroscopy. Test results will be reported as micrograms of arsenic per gram of hair (μg/g). Reference ranges for concentrations of arsenic in hair from unexposed populations range from 0.02 to 1.0 ppm.

Indoor Dust Sampling

Sample collection is performed utilizing the Nilfisk GS-80 vacuum cleaner equipped with a high efficiency particulate air (HEPA) filter. Soil and other particulate matter with aerodynamic diameters of approximately 5-micrometers (um) and larger, embedded within the carpet, are collected and returned to the laboratory for sieving and analysis. Sampling will be from the main home entry area and other areas where small children play or are likely to play.

1. Prior to sample collection at the house to be sampled, complete a sample data sheet, recording all requested information and sketch the area to be sampled.

2. Two sample locations will be selected in each home. Each sample is collected with a dedicated sampling train that has been properly assembled, cleaned, and decontaminated to ensure sample integrity. The size/weight of each sample is dependent on the goals and objectives of the sampling event, the analyses requested, and the desired method detection levels (MDLs).

The dust weight calculations for the final sieved dust fraction is performed in accordance with ASTM Method D 422. Dividing the final dust weight by the area sampled (expressed in m2) provides dust loading per square meter, in g/m2. When the analysis results are received, the loading of analyte per square meter of carpet area (μg/m2) can be calculated in the same way. Analysis will also provide μg/kg concentration. If total (gross) dust loading of the sampled area needs to be calculated, the total dust weight before sieving must be obtained. The total dust weight is divided by the area sampled to obtain total dust loading per square meter.

Survey Forms

In addition to completing a consent form, each family will be asked to complete a short questionnaire that solicits information on the family members' exposure history.

Reporting Results

Individual test results and an explanation of their significance will be provided to the participants in writing. An ATSDR physician will be available to discuss individual results by phone. Recommendations for follow-up actions will be made, if warranted, including repeat testing or consultation with an occupational/environmental physician.

Individual test results will not be made available to the public, and confidentiality will be protected according to Federal and State laws. At the conclusion of the investigation, ATSDR will prepare a report which will summarize the findings of the investigation, but will not reveal personal identifiers.

References

ATSDR; Toxicological Profile for Arsenic (Update); September 2000.

ATSDR; Health Consultation: Exposure Investigation, Spring Valley Chemical Munitions (a/k/a American University Child Development Center), Washington, District of Columbia, DC, March 8, 2001.

ATSDR; "Report assessing public health implications of arsenic in soils at the American University Child Development Center," March 28, 2001.

Kalman, D.A. and others. The Effect of Variable Environmental Arsenic Contamination on Urinary Concentrations of Arsenic Species. Environmental Health Perspectives, Vol. 89, pp. 145-151, 1990.

National Research Council (NRC). Arsenic in Drinking Water. Washington, DC: National Academy Press, 1999.

Washington Occupational Health Associates, Inc. Health Consultation: Arsenic Exposure Investigation at American University, Washington, DC, March 26, 2001.


End of Document

Top of Page

 
Contact Us:
  • Agency for Toxic Substances and Disease Registry
    4770 Buford Hwy NE
    Atlanta, GA 30341
  • 800-CDC-INFO
    (800-232-4636)
    TTY: (888) 232-6348
    Contact CDC-INFO
  • New Hours of Operation
    8am-8pm ET/Monday-Friday
    Closed Holidays
USA.gov: The U.S. Government's Official Web PortalDepartment of Health and Human Services
Agency for Toxic Substances and Disease Registry, 4770 Buford Hwy NE, Atlanta, GA 30341
Contact CDC: 800-232-4636 / TTY: 888-232-6348

A-Z Index

  1. A
  2. B
  3. C
  4. D
  5. E
  6. F
  7. G
  8. H
  9. I
  10. J
  11. K
  12. L
  13. M
  14. N
  15. O
  16. P
  17. Q
  18. R
  19. S
  20. T
  21. U
  22. V
  23. W
  24. X
  25. Y
  26. Z
  27. #