Sharps Corner/Porcupine Area
PINE RIDGE INDIAN RESERVATION
(a/k/a CHEYENNE RIVER BASIN)
RAPID CITY, PENNINGTON COUNTY, SOUTH DAKOTA
The Pine Ridge Indian Reservation in South Dakota requested assistance from the Agency for Toxic Substances and Disease Registry (ATSDR) to determine if exposure to possible contaminants in selected private well water and indoor air in the Sharps Corner/Porcupine area would adversely affect the health of area residents. This health consultation identifies potential human exposures and possible health effects related to chemicals detected in private well water and in indoor air sampling data from selected homes on the Pine Ridge Indian Reservation in the Sharps Corner/Porcupine Area. This health consultation is not intended as a complete assessment of all environmental risks in the area, nor is it intended to encompass all private wells/indoor air on the Pine Ridge Indian Reservation. The primary contaminants of concern for the Sharps Corner/Porcupine area are radionuclide levels in the drinking water and radon levels in the indoor air of private residences.
The Pine Ridge Indian Reservation is in south-central South Dakota. The study area topography is diverse. Sod-covered tablelandsremnants of alluvial depositsdominate the northwestern part. The Sharps Corner/Porcupine area is south-centrally located within the reservation, on the border with Nebraska. According to the U.S. Census the Pine Ridge Indian Reservation has about 15,000 members. Groundwater from wells and springs is the predominate source of domestic supply within the Indian Reservation . South Dakota has large, naturally occurring radon pockets that vary in concentration all across the state and that can adversely affect indoor air (See Appendix A).
ATSDR was asked to evaluate private drinking wells of 16 Sharps Corner/Porcupine area homes where residents had been diagnosed with or had recently died from cancer. Initial samples were taken from just three wells that provided water to known cancer patients, decedents or both (See Appendix B). The initial sampling data in Appendix A led ATSDR to conclude that radionuclides were the drinking water contaminant of concern for the Sharps Corner/Porcupine area. The Indian Health Service (IHS) conducted follow-up sampling for radionuclides according to ATSDR recommendations. IHS was able to obtain private well water used by all 16 residentswith some exceptions as described in the notations on the table in Appendix C. In addition, radon samples were taken at residences of 10 of the 16 cancer patients or decedents. Radon was determined to be a contaminant of concern (See Table 1).
In December of 2000 ATSDR, in conjunction with the IHS Pine Ridge Service Unit, conducted a community meeting with the Sharps Corner/Porcupine area residents. The purpose of the meeting was to review the sampling results obtained by the three previously mentioned studies. IHS discussed the sampling methods used and sampling locations chosen in the Sharps Corner/Porcupine area. ATSDR staff members provided their interpretation of the sampling data and answered questions pertaining to potential health effects.
During December of 1999 and January of 2000 Pine Ridge IHS took water samples from eight residential private wells in the Sharps Corner/Porcupine area. The water samples had a full environmental chemistry analysis and were compared to the Environmental Protection Agencies (EPA) Maximum Contaminant Levels (MCLs) (See Appendix B for complete results). Water samples were taken from either the kitchen or the bathroom taps in the residents' homes. Three of these residents were identified on the list of 16 cancer cases reported in the Sharps Corner/Porcupine area. With the exception of Radionuclides, all water sample analyses were reported below EPA's MCLs. Again, the initial sampling data contained in Appendix B led ATSDR to conclude that radionuclides were the drinking water contaminant of concern for the Sharps Corner/Porcupine area. IHS conducted follow-up sampling for radionuclides according to ATSDR recommendations. IHS was able to obtain private well water used by all 16 residents, with some exceptions as described in the notations on the table in Appendix C.
IHS found radionuclides at varying concentrations in all 16 private well water samples taken in the Sharps Corner/Porcupine area (See Appendix C). To compare those samples to EPA's MCL for uranium of 30µg /L, isotopic analysis results were converted to total uranium (i.e., Utotal = U-238 + U-234 + U-235). The highest concentration of Utotal found in the 16 private well water samples was 0.0759mg/L (i.e., 75.9 µg /L)above the MCL for uranium. Whenever ATSDR finds environmental concentrations above EPA's MCL, additional assessments are required to determine the potential impact of any exposure. Moreover, if uranium is ingested, health studies have identified kidneys as the target organ or primary organ of concern . Therefore, worst-case kidney doses were calculated for uranium using the highest concentration recorded of 75.9 µg /L (See Appendix D for uranium Kidney Dose Calculations) to determine if even the highest levels found at Sharps Corner/Porcupine area could affect the health of residents.
During April of 2000 the Pine Ridge IHS service unit collected radon samples from nine residences, of which eight were identified on the list of 16 cancer cases/decedents reported in the Sharps Corner/Porcupine area (See Table 1). Samples were taken in each home on the first floor and living room areas. In three homes additional samples were taken in the basements, in the laundry areas, and in some second floors. Radon samples were collected according to EPA methods (Radon 222 in Air/EPA 520 / 5-87-005 / Ramses II 4" Open face detector). Three of the 9 radon samples were found slightly above EPA's action level of 4.0 pCi/L. The EPA and Centers for Disease Control and Prevention (CDC) have used a continuous exposure level of 4 pCi/L or 0.02 WL as a guidance level at which further testing, remedial action or both are indicated . Table 1 shows the indoor air radon levels for homes in Sharps Corner / Porcupine Area.
|Residence||Number of Residents||Number of Cancer Patients/Deaths||Type of Cancer||Sampling Site||pCi/L|
|Residence 1||1||1||Not Identified to ATSDR||First Floor / |
|Residence 2||1||1||Not Identified to ATSDR||First Floor / |
|Residence 3||1||1||Not Identified to ATSDR||First Floor / |
|Residence 4||2||1||Non-Small Cell Adneo CA of Lung||Basement / Laundry||5.19|
|First Floor / |
|Residence 5||1||1||Cancer of the Lung||First Floor / |
|Residence 6||3||2||Not Identified to ATSDR||First Floor / |
|Residence 7||3||2||Adenocarcinoma of Sigmoid Colon||Second Floor / |
|Basement / |
|Residence 8||1||1||Squamous Cell Carcinoma Right Lung||First Floor / Living Room||4.4|
|Residence 9||1||0||Class IV Poorly Differentiated Carcinoma||First Floor / Living Room||1.15|
|Second Floor/ Living Room||0.59|
*Bold numbers in the pCi/L column exceed the EPA action level of 4.0 pCi/L
†Cancer information obtained from Pine Ridge Indian Health Service Hospital
ATSDR examined the possible exposure pathways and determined that inhalation and ingestion are the primary pathways of concern. By drinking tap water, some residents in the Sharps Corner/Porcupine area are exposed to radionuclides via ingestion. In addition, some residents in the Sharps Corner/Porcupine area are exposed to Radon via inhalation in their homes.
For this analysis, uranium in private well water and radon in residential homes in the Sharps Corner/Porcupine area have been found to exceed comparison values. Therefore, the discussion of public health implications focuses on the detected levels of uranium in residential well water and the detected levels of radon in residential homes.
Uranium is a natural and commonly occurring radioactive element. It is found in very small amounts in the form of minerals, but it can be processed into a silver-colored metal. Rocks, soil, surface and underground water, air, and plants and animals all contain varying amounts of uranium. Typical concentrations in most materials are a few parts per million (ppm). Natural uranium is a mixture of three types (or isotopes), written as 234U, 235U, and 238U, or as U-234, U-235, and U-238, and read as "uranium two thirty-four," and so on. All three isotopes behave chemically the same, so any combination of the three would have the same chemical effect in one's body. But each form of uranium is a distinct radioactive material with varying radioactive properties. That is why we must look at each of the three isotopes in a sample of uranium to determine its total radioactivity .
Uranium in water originates from different sources; most is from uranium dissolving out of rocks and soil which water runs over and through. Only a very small part is from the settling of uranium dust out of the air. Some of the uranium is simply suspended in water, in the same way mud is suspended in water. The amount of uranium EPA has measured in drinking water in different parts of the United States is generally less than 1.5µg (1 pCi) for every liter of water. In Region 8 were Pine Ridge Reservation is located EPA has found uranium levels between 0.06-6 pCi/L. Because of the nature of uranium, not much of it gets into fish or vegetables; and most of the uranium livestock might ingest they quickly eliminate in urine and feces. EPA has set a goal of no uranium in drinking water. EPA calls this a Maximum Contaminant Level Goal (MCLG). Nevertheless, EPA recognizes that currently there is no practical way to meet it. Effective December 8, 2003, the MCL for uranium will be set to 30µg /L .
Scientists have never detected harmful radiation effects from low levels of natural uranium, although some such effects could be possible. In fact, with any radioactive material like uranium, there is a chance of developing cancer. On the other hand, natural and depleted uranium are only weakly radioactive and are not likely to cause cancer. No human cancer of any type has ever been seen as a result of exposure to natural or depleted uranium . That said, however, scientists have seen harmful chemical effects from uranium. However, these effects have only been seen in certain acute poisoning incidents in humans in which a few individuals have developed signs of kidney disease. Animals have also developed kidney disease after they have been treated with large amounts of uranium. Thus it is possible that intake of a large amount of uranium might damage the kidneys . The highest concentration of Utotal found in the 16 private well water samples was 0.0759mg/L (i.e., 75.9µg /L)-above the MCL for uranium. Health studies have identified kidneys as the target organ or primary organ of concern for the ingestion of uranium. Therefore, kidney dose calculations for uranium were calculated using the highest concentration recorded of 75.9µg /L (See Appendix D for uranium Kidney Dose Calculations). ATSDR assumed a worst-case scenario for the kidney dose calculation and compared it to
- the maximum permissible concentration adopted by the International Commission of Radiological Protection, of 3 µg /gkidney1 , and
- a derived limit for members of the public and sensitive populations (e.g., children) of 0.1µg /gkidney2.
The worst-case kidney dose calculation (0.025 µg /gkidney) was found to be lower than the maximum permissible concentration. It was also found to be lower than the derived limit for members of the public and sensitive populations. Therefore, ingestion of uranium from private wells in the Sharps Corner/Porcupine area would not contribute to lung cancer and would not pose a kidney-related public health threat.
Radon is a naturally occurring radioactive gas without color, odor, or taste. Radon gas is one part of a natural radioactive process, known as "decay," in which larger, more complex elements such as uranium and radium break down into smaller, less complex elements, giving off energy in the process. When radon decays, products known as "daughters" are created. Radon gas itself is relatively harmless until it decays into these daughters, which in turn release damaging energy particles .
Radon comes primarily from the soil under a building. It can be found almost anywhere because radium, the "parent" of radon, is present in most soils. Average concentrations of radium are usually low and radon gas will usually migrate harmlessly into the atmosphere through the soil. But if a building is erected over a radon source, the gas can become trapped inside and build to hazardous levels. Common entry points include cracks in basement floors, slab joints, floor drains, sump pits, and porous cinder block walls. Basements typically contain the highest concentrations of radon .
If inhaled, radon daughters (polonium-218 and polonium-214, in solid form), unattached or attached to the surface of aerosols, dusts, and smoke particles, can become deeply lodged or trapped in the lungs. Once there, they can radiate and penetrate the cells of mucous membranes, bronchi, and other pulmonary tissues. Lung cancer due to inhalation of radon decay products constitutes the only known risk associated with radon. In studies done on miners, variables such as age, duration of exposure, time since initiation of exposure andespeciallythe use of tobacco have been found to influence individual risk. In fact, the use of tobacco increases the risk of radon-induced lung cancer. The World Health Organization (WHO) [IARC 1988] and the U.S. Department of Health and Human Services, as well as EPA, have classified radon as a "Class A " known human carcinogen. They have all arrived at this conclusion because of the wealth of biological and epidemiological evidence and data showing the connection between exposure to radon and lung cancer in humans. Still, not everyone exposed to elevated levels of radon will develop lung cancer. Also, the amount of time between exposure and the onset of the disease can be many years .
Three of the nine radon samples were found slightly above EPA's action level of 4.0 pCi/L. The risk of developing lung cancer is directly proportional to the level and duration of exposure to radon; that is, the higher the radon concentration, the higher the lung cancer risk. The air concentration of radon in the homes ranged from 0.73 to 5.19 pCi/L. The highest concentration (5.19 pCi/L) was detected in a non-living area of a house (basement). Radon levels in the upper floors of this house would likely be less if the radon were entering the house through the basement. The highest radon concentration detected in the living area of a house was 4.55 pCi/L, which only slightly exceeds the EPA action level of 4 pCi/L. Therefore, radon levels do not pose a significant increased risk of lung cancer to residents in homes sampled for radon in the Sharps Corner/Porcupine area.
However, smoking combined with exposure to radon is an especially serious health risk. A 1989 study by researchers from the National Institute for Occupational Safety and Health, the Centers for Disease Control, the Harvard School of Public Health, and the University of California at Davis demonstrated a greatly increased lung cancer risk in uranium miners who smoke and who were exposed to high radon concentrations. In fact, compared to typical non-smoking populations, these miners had 9 to 12 times the risk of developing lung cancer . Evidence from some of the epidemiological studies of underground miners, primarily U.S. uranium miners, indicates that radon exposure and smoking could be synergistic: either smoking or radon exposure independently increase the risk of lung cancer, but exposure to both greatly enhances that risk.
Cancer is not a single disease. It is a group of more than 200 different diseases. Various types of cancer have various causes which are likely to depend on many factors. Most cancers can not be traced to a chemical, environmental, genetic, immunologic, or viral origin. Cancers also can arise spontaneously from causes yet unexplained. Still, much progress has been made in identifying possible causes of cancer, including chemicals and other substances. Exposure to substances such as certain chemicals, metals, or pesticides can increase the risk of cancer. Any chemical known to cause cancer is labeled a carcinogen. Asbestos, nickel, cadmium, uranium, radon, vinyl chloride, benzidene, and benzene are all examples of well know carcinogens. Carcinogens (i.e. radon) can act alone or with another carcinogen, such as cigarette smoke, to increase the risk of cancer. In fact, the most common carcinogens are those present in cigarette smoke. Tobacco smoke contains at least 60 carcinogens and 6 developmental toxicants. In addition to responsibility for 80 to 90% of lung cancers, cigarette smoking is also associated with cancers of the mouth, pharynx, larynx, esophagus, pancreas, kidney, and bladder. Avoiding tobacco products is one way to decrease one's risk of cancer. As stated, because cancer is not a single disease it does not have a single cause. Many causes or risk factors can contribute to one's chances of developing cancer. Risk factors are different with each type of cancer. It is important to remember that 1 in 3 persons will develop a cancer during their lifetime. Risk factors can include such things as age, race, sex, genetic factors, diet, as well as exposure to chemicals, to radiation, and to tobacco. .
In communities faced with air, water, or food contamination, the many physical differences between children and adults demand special emphasis. Children could be at greater risk than are adults from certain kinds of exposure to hazardous substances. Children play outdoors and sometimes engage in hand-to-mouth behaviors that increase their exposure potential. Children are shorter than are adults; this means they breathe dust, soil, and vapors close to the ground. A child's lower body weight and higher intake rate results in a greater dose of hazardous substance per unit of body weight. If toxic exposure levels are high enough during critical growth stages, the developing body systems of children can sustain permanent damage. Finally, children are dependent on adults for access to housing, for access to medical care, and for risk identification. Thus adults need as much information as possible to make informed decisions regarding their children's health.
Uranium ingestion from private wells in the Sharps Corner/Porcupine area would not pose an increased risk to children. The exposure limit for the general public takes into consideration sensitive populations. In addition, radon poses no significantly increased lung cancer risk to children in homes sampled for radon in the Sharps Corner/Porcupine area. The EPA action level considers sensitive populations.
Some homes in the Sharps Corner/Porcupine area have indoor radon levels slightly above the EPA's action level of 4.0 pCi/L. In addition, various homes in the Sharps Corner/Porcupine area have uranium levels in their drinking water above the EPA MCL of 30µg /L. Given these findings, ATSDR concludes that
- Radon poses no apparent public health hazard to residents in homes sampled for radon in the Sharps Corner/Porcupine area. "No apparent" actually means "NO HAZARD although some exposure may be occurring. This public health hazard category was assigned because the highest radon concentration detected in the living area of a house was 4.55 pCi/L, which only slightly exceeds the EPA action level of 4 pCi/L. Therefore, these radon levels do not pose a significant increased risk of lung cancer.
- Either smoking or radon exposure can independently increase the risk of lung cancer; however, exposure to both greatly enhances that risk.
- Ingestion of uranium from private wells in the Sharps Corner/Porcupine area poses no apparent public health hazard because the worst-case-scenario kidney dose calculation was found to be lower than the acceptable exposure limit for the general public.
- To ensure indoor radon levels are not rising, conduct a second indoor radon test in those residents' homes that contained radon levels above EPA's action level of 4.0 pCi/L.
- ATSDR recommends public health education regarding cancer, lung cancer, radon, and smoking.
LTJG Jasen M. Kunz. Environmental Health Scientist, ATSDR/DHAC/OD/OTA
LCDR Daphne Moffett, Ph.D. Senior Environmental Health Scientist Officer ATSDR/DT/RIB
Michael J. Grayson, MS, Health Physicist CDC/NCEH/EHHE
Dean S. Seneca, MPH, MCURP Assistant Director Office of Tribal Affairs DHAC/OD/OTA
This Pine Ridge Indian Reservation, Sharp's Corner, Porcupine Area Health Consultation was prepared by the Office of Tribal Affairs, Office of the Director, Division of Health Assessment and Consultation, Agency for Toxic Substances and Disease Registry. The health consultation is in accordance with guidelines and procedures present at the time the health consultation was begun.
Jasen M. Kunz
Technical Project Officer
DHAC, OD, OTA
This health consultation has been reviewed by the Division of Health Assessment and Consultation, ATSDR. ATSDR concurs in the health consultation findings.
Assistant Director Office of Tribal Affairs
DHAC, OD, OTA
- Heakin AJ. Water quality of selected springs and public supply wells, Pine Ridge Indian Reservation, South Dakota 1992-1997. Denver, CO: US Geological Survey: 99-4063; 2000.
- Agency for Toxic Substances and Disease Registry. Toxicological profile and public health statement for uranium. Atlanta: US Department of Health and Human Services; 1999.
- US Environmental Protection Agency. List of drinking water contaminates and maximum contaminant levels. Washington DC: EPA 816-F-02-013; July 2000.
- Leggett RW. Health Physics 1989;57(3):365-83.
- Agency for Toxic Substances and Disease Registry. Toxicological profile for radon. Atlanta: US Department of Health and Human Services; 1990.
- National Council on Radiation Protection and Measurements (NCRP). Evaluation of occupational and environmental exposures to radon and radon daughters in the United States. Bethesda, MD: NCRP Report No. 78; 1984.
- US Environmental Protection Agency. A citizen's guide to radon. Washington: Air and Radiation Division (ANR-464); 1992.
- Roscoe RJ et al. Lung cancer mortality among non-smoking uranium miners exposed to radon daughters. J Am Med Assoc 1989;262 (5):629-33.
- Agency for Toxic Substances and Disease Registry. Cancer fact sheet. Atlanta: US Department of Health and Human Services; 1990.
South Dakota Levels
Since the late 1980's, radon levels have been measured throughout the state of South Dakota. This data has been collected and compared to geological formations to yield the map shown below. The zone classifications are based upon being able to predict the likelihood of finding certain ranges of radon concentrations when conducting short-term radon measurements. The eastern portion of the state is Zone 1 with the balance being Zone 2. There are no Zone 3 areas in South Dakota.
Available at: http://www.state.sd.us/denr/DES/AirQuality/radon1.htm#South%20Dakota%20Levels. Last accessed 19 August 2003.
|EPA MCL||Spec.# |
|Spec. # |
|Spec. # |
|Gross alpha particle activity||15 pCi/L||3.0 +/- 0.4 pCi/L||47.5 +/- 13.1 pCi/L||11.4 +/- 0.8 pCi/L||3.6 +/- 0.4 pCi/L||33.9 +/- 8.8 pCi/L||13.8 +/- 1.5 pCi/L||41.8 +/- 1.5 pCi/L||21.2 +/- 1.0 pCi/l|
|uranium||28.9 pCi/L||20.2 pCi/L||39.5 pCi/L||14.9 pCi/L|
|Natural uranium||0.04 mg/L||0.03 mg/L||0.06mg/L||0.02 mg/L|
|Corrected gross alpha particle activity||18.6 pCi/L||13.7 pCi/L||2.3 pCi/L||6.3 pCi/L|
|Beta particles and photon emitters||4 mrem/yr|
|Radium 226 & Radium 228 Combined||5 pCi/L|
|Radium 226||<0.3 +/- 0.2 pCi/L||<0.3 +/- |
|<0.3 +/- 0.1 pCi/L||<0.3 +/- 0.2 pCi/L||<0.3 +/- 0.2 pCi/L||<0.3 +/- 0.1 pCi/L|
|Radon||133 pCi/L||875 pCi/L||1441 pCi/L||1013pCi/L||691 pCi/L||3372 pCi/L||4674 pCi/L||802 pCi/L|
*Bolded numbers exceed established EPA maximum contaminant levels (MCLs)
|Sample ID and Residence||Unfiltered Water||Filtered Water||Solids / Filter|
|Gamma Scan |
|Gamma Scan |
|Gross Alpha |
|Gross Beta |
|Natural uranium |
|Natural uranium |
|Gamma Scan |
|Gross Alpha |
|Gross Beta |
|Natural uranium |
|Natural uranium |
|Sample 1* |
|<50||2||495||<50||10.7 +/- 1.0||14.0 +/- 1.8||8.1 +/- 1.4||<0.2||5.3 +/- 1.1||0.0132||8.9||NAg||0.5 +/- 0.07||1.1 +/- 0.05||0.20 +/- 0.12||<0.05||0.15 +/- 0.10||<0.00007||<0.05|
|Sample 2† |
|<50||14||511||<50||10.5 +/- 1.0||18.0 +/- 1.8||9.6 +/- 1.5||<0.2||5.4 +/- 1.1||0.0138||9.3||NAg||1.1 +/-0.10||2.1 +/-0.10||0.10 +/- 0.05||<0.05||<0.05||0.00007||0.05|
|Sample 6 |
|<50||<1.0||390||<50||7.8 +/- 1.0||5.4 +/- 1.6||6.6 +/- 1.1||0.5 +/- 0.3||3.3 +/- 0.8||0.0069||4.67||<50||0.19 +/- 0.05||0.55 +/- 0.05||0.07 +/- 0.05||<0.05||<0.05||<0.0001||<0.05|
|Sample 9 |
|<50||<1.0||492||<50||12.7 +/- 1.0||10.2 +/- 1.7||9.9 +/- 1.4||0.4 +/- 0.3||6.2 +/- 1.1||0.0124||8.4||<50||0.12 +/- 0.05||0.24 +/- 0.05||0.17 +/- 0.10||0.10 +/- 0.07||<0.05||<0.0001||<0.05|
|Sample 10 |
|<50||<1.0||231||<50||9.4 +/- 1.0||5.1 +/- 1.5||5.7 +/- 1.0||0.3 +/- 0.2||3.2 +/- 0.7||0.0054||3.66||<50||0.14 +/- 0.05||0.22 +/- 0.05||0.07 +/- 0.07||0.12 +/- 0.07||0.14 +/- 0.07||0.0001||0.07|
|Sample 13‡ |
|<50||3||731||58.6 +/- 11.6||28.97 +/- 1.0||19.6 +/- 1.9||25.6 +/- 2.5||0.8 +/- 0.5||14.0 +/- 1.8||0.0316||21.4||NAg||1.2 +/- 0.1||1.4 +/- 0.1||<0.05||<0.05||<0.05||<0.00007||<0.05|
|Sample 14 |
|70||<1.0||470||<50||9.8 +/- 1.0||8.0 +/- 1.7||8.5 +/- 1.2||<0.2||4.3 +/- 0.8||0.01||6.8||NAg||0.17 +/- 0.05||0.32 +/-0.05||<0.05||<0.05||<0.05||<0.0001||<0.050|
|Sample 18 |
|<50||<1.0||581||<50||15.7 +/- 1.0||12.4 +/- 1.8||16.5 +/- 1.8||1.3 +/- 0.5||6.7 +/- 1.1||0.0136||9.2||<50||<0.24||0.26 +/- 0.05||<0.05||<0.05||<0.05||0.0031||2.115|
|Sample 19§ |
|<50||25||905||<50||55.0 +/- 1.0||33.8 +/- 2.2||45.5 +/- 3.2||0.6 +/- 0.4||22.6 +/- 2.2||0.0473||32||NAg||9.0 +/- 0.3||12.9 +/- 0.1||0.5 +/- 0.2||0.2 +/- 0.1||0.5 +/- 0.2||0.0006||0.41|
|Sample 1/3/4/15¶ |
|<50||42||561||<50||21.0 +/- 1.0||24.3 +/- 2.0||15.1 +/- 2.0||1.0 +/- 0.6||8.2+/- 1.5||0.0204||13.8||NAg||0.9 +/- 0.1||2.0 +/- 0.1||0.27 +/- 0.14||<0.05||0.14 +/- 0.10||0.0004||0.28|
|Sample 5/8 |
|<50||<1.0||483||<50||17.1 +/- 1.0||11.1 +/- 1.7||15.6 +/- 1.6||0.4 +/- 0.3||9.6 +/- 1.3||0.0088||5.96||<50||0.17 +/- 0.05||0.33 +/- 0.05||<0.05||<0.05||<0.05||0.0001||0.1|
|Sample 7/16 |
|<50||<1.0||341||<50||5.1 +/- 1.0||8.4 +/- 1.6||4.0 +/- 0.8||<0.2||2.1 +/- 0.6||0.0048||3.25||<50||0.19 +/- 0.05||0.58 +/- 0.05||0.13 +/- 0.08||<0.05||<0.05||0.0001||0.07|
|Sample 11/12 (ALT)** |
|<50||<1||424||<50||6.2 +/- 1.0||13.0 +/- 1.7||3.6 +/- 1.0||<0.2||1.5 +/- 0.6||0.0034||2.3||NA††||0.1 +/-0.05||0.3 +/- 0.05||<0.05||<0.05||0.2 +/- 0.1||<0.00007||<0.05|
* Residence 8 currently served by OSRWSS, this sample was taken from the well adjacent to her home.
† This sample was taken from an abandoned well that served that served Residence 13.
‡ Residence 4 is currently served by OSRWSS, this sample was taken from the private well that previously served the residence.
§ This residences is currently served by OSRWSS, this sample is from a well that previously served the residence.
¶ The residences of all these individuals are currently served by OSRWSSthis sample is from a well that previously served the residence.
** Residence 11 well could not be sampledthis sample was taken from the nearest private well, approximately 250 ft. away.
†† Results not availablewill forward results at a later date if possible.
Used initial water sampling results (Appendix A) and follow up water sampling results (Appendix B) containing uranium (U) isotopic analysis sampling results for private well water in the Sharps Corner/Porcupine area. Converted the isotopic analysis results to total U (i.e., Utotal = U-238 + U-234 + U-235), and selected the largest concentration to base calculations on. The largest [Utotal] = 0.0759 mg/L
(i.e., 75.9 µg/L).
Ingestion rate = 2.0 L
Gastrointestinal uptake = 10% (ICRP Publication 30, Part 1, sets the value at 5% for water-soluble inorganic compounds)
Kidney uptake = 12% with a biologic removal rate of 50% in 6 days and 0.052% with a biologic removal rate of 1,500 days (consistent with ICRP)
Mass of one kidney = 310 g
Occupational exposure limit = 2 - 3 µg/gKidney
Exposure limit for the general public = 0.1 µg/gKidney
Kidney dose calculations:
Intake = 75.9 µg/L x 2.0 L/day = 151 µg/day
Gastrointestinal uptake = 151 µg/day x 10% = 15.1 µg/day
Kidney uptake = 15.1 x 12% = 1.81 µg/day
The amount of U in the kidneys reaches equilibrium based on intake and biologic removal (i.e., l = 0.693/6 days = 0.115/day).
Amount in equilibrium per mass of kidney = 15.7 µg/ (2 x 310 g) = 0.025 µg/gKidney
(i.e., kidney dose = 0.025 µg/gKidney)
This kidney dose is lower than the general public limit of 0.1 µg/gKidney; therefore, ingestion of [U] from private wells yields no renal toxic effects.
- Any one of a group of diseases that occur when cells in the body become abnormal and grow or multiply out of control
- A substance that causes cancer.
- Comparison value (CV):
- Calculated concentration of a substance in air, water, food, or soil that is unlikely to cause harmful (adverse) health effects in exposed people. The CV is used as a screening level during the public health assessment process. Substances found in amounts greater than their CVs might be selected for further evaluation in the public health assessment process.
- The amount of a substance present in a certain amount of soil, water, air, food, blood, hair, urine, breath, or any other media.
- A substance that is either present in an environment where it does not belong or is present at levels that might cause harmful (adverse) health effects.
- Contact with a substance by swallowing, breathing, or touching the skin or eyes. Exposure may be short-term [acute exposure], of intermediate duration, or long-term [chronic exposure].
- Exposure pathway:
- The route a substance takes from its source (where it began) to its end point (where it ends), and how people can come into contact with (or get exposed to) it. An exposure pathway has five parts: a source of contamination (such as an abandoned business); an environment media and transport mechanism (such as movement through groundwater); a point of exposure (such as a private well); a route of exposure (eating, drinking, breathing, or touching), and a receptor population (people potentially or actually exposed). When all five parts are present, the exposure pathway is termed a completed exposure pathway.
- Health consultation:
- A review of available information or collection of new data to respond to a specific health question or request for information about a potential environmental hazard. Health consultations are focused on a specific exposure issue. Health consultations are therefore more limited than a public health assessment, which reviews the exposure potential of each pathway and chemical.
- The act of swallowing something through eating, drinking, or mouthing objects. A hazardous substance can enter the body this way.
- Milligram per kilogram.
- No apparent public health hazard:
- A category used in ATSDR's public health assessments for sites where human exposure to contaminated media might be occurring, might have occurred in the past, or might occur in the future, but where the exposure is not expected to cause any harmful health effects.
- Any radioactive isotope (form) of any element.
- Route of exposure:
- The way people come into contact with a hazardous substance. Three routes of exposure are breathing [inhalation], eating or drinking [ingestion], or contact with the skin [dermal contact].
- A portion or piece of a whole. A selected subset of a population or subset of whatever is being studied. For example, in a study of people the sample is a number of people chosen from a larger population. An environmental sample (for example, a small amount of soil or water) might be collected to measure contamination in the environment at a specific location.
1 The maximum permissible concentration is defined for occupational exposures as the kidney dose that can be tolerated without serious effects.
2 The maximum permissible concentration is reduced by a factor of ten to arrive at a value acceptable for the general public (i.e., non-occupationally exposed individuals) and then reduced by another factor of 3 to protect sensitive populations.