PETITIONED PUBLIC HEALTH ASSESSMENT
FIELDS BROOK NPL SITE
(SPECIFICALLY CONCERNING RADIOLOGICAL CONTAMINANTS AT RMI TITANIUM COMPANY)
ASHTABULA, ASHTABULA COUNTY, OHIO
In the past, barrels of mixed wastes, containing uranium-238, uranium-235, technetium-99, and trichloroethylene (TCE), were stored on the site. RMI held a RCRA permit through the EPA, for storage of mixed wastes. Core samples of the first five centimeters of soils on the site show that uranium concentrations have ranged from 1.1 picocurie to as high as 2,439 picocuries per gram (pCi/g) (1984 Environmental Survey Report). The facility has also emitted mixed uranium metal and oxide dusts through six stacks, and during its history released approximately 850 kilograms of uranium or 0.57 Curies into the atmosphere. RMI has also discharged nearly 3,000 kilograms or just over two Curies of insoluble uranium oxide in process water over the last 29 years. Core sampling of the first five centimeters of sediments at the plant outfall into Fields Brook have shown average uranium concentrations (as uranium oxide) of 4.9 pCi/g to as high as 55 pCi/g (1984 Environmental Survey Report), which compares to the US Nuclear Regulatory Commission's limit of 35 pCi/g of uranium, on average, for unrestricted use.
(metal and oxide)
|Media||air||surface water||ground water||soil||ground water||ground water|
Data were taken directly from: ANNUAL ENVIRONMENTAL REPORT for RMI COMPANY
EXTRUSION PLANT ASHTABULA, OHIO, for the period 1/1/88 through 12/31/88
MDL - minimum detection limit
pCi - picocuries = 10-12 Curies or 3.7x10-2 decays per second
µCi - microcuries = 10-6 Curies or 3.7x104 decays per second
ppm - parts per million
Groundwater sampling from 30 monitoring wells has shown groundwater contamination at the north side of the site by TCE (84 parts per million), uranium (150 pCi/liter or 0.2 ppm), and technetium-99 (100,000 pCi/liter or 0.006 ppm). The suspected source of the contamination is a small (10 x 30 foot) clay-lined former evaporation pit that received sodium nitrate solution containing trace amounts of uranium and technetium-99 from 1963 until 1984. An unauthorized disposal of TCE into the pit before 1972 is the suspected reason for the TCE contamination. The groundwater contamination plume extends about 100 feet north of the former evaporation pit, and had not been contained.
The RMI plant has emitted coarse uranium metal and oxide dusts from six stacks for the last 29 years, and some of that material has settled just outside the plant boundary. Soil samples from five to 250 feet outside the north fence have shown as high as 463 pCi/g of uranium. The Nuclear Regulatory Commission (NRC) guideline for allowed concentrations of uranium in soil in uncontrolled areas is only 35 pCi/g . The predominant land uses in the sampled areas are undeveloped or industrial. Just beyond 500 feet from the facility, the uranium concentration falls within normal background levels for Ohio, or less than 4.4 pCi/g. The data show a parabolic trend typical of a large particle distribution as opposed to respirable particles. Table 3 shows the uranium concentrations in soils as reported in the ANNUAL ENVIRONMENTAL REPORT for the RMI Company, for the period January 1, 1988, to December 31, 1988 .
|Distance from Plant||Number of Samples||Maximum Concentration
|5 to 250 ft. from North Fence||10||463||2.0||95.3||35|
|1.25 to 1.5 mile||5||1.21||0.29||0.70||35|
|3.25 to 3.5 miles||2||0.74||0.36||0.55||35|
|Note:||1. Naturally-occurring uranium concentrations in Ohio soils range from 1.2 to 4.4 pCi/g. |
2. The annual, six-inch deep composite sediment samples for the years 1987 and 1988 show levels of uranium at or below background levels for naturally-occurring uranium as shown in Table 4 (copied from ANNUAL ENVIRONMENTAL REPORT for the RMI Company for the period January 1, 1988, to December 31, 1988).
|Location||Distance from Outfall (feet)||1988 Uranium Concentration
|1987 Uranium Concentration
The TCE groundwater plume, mentioned in the previous section, extends outside the northern boundary. The levels measured off site are just above the detection limit at 0.003 ppm, according to the 1988 Environmental Survey Report.
The findings of this Addendum to the Fields Brook Health Assessment are based primarily upon data developed by the U.S. Department of Energy, Oak Ridge Operations, and its contractor the Westinghouse Materials Company of Ohio, and were reviewed by the U.S. Environmental Protection Agency, the Nuclear Regulatory Commission, and the state of Ohio. There are still no direct measurements of residential soil, as indicated in the original public health assessment. Where descriptions were provided, the QA/QC measures appeared to be consistent with measures normally taken with environmental and radiological sampling and analysis. The data are assumed to be accurate within the QA/QC procedures employed.
No physical hazards were noted off site, and access to the site was not possible due to the fence and security on site.
To determine whether neighboring residents are being exposed to contaminants from the site, ATSDR evaluates the environmental, and human components that lead to human exposure. This pathways analysis consists of five components:
1) A source of contamination.
2) Transfer through an environmental medium.
3) A point of exposure.
4) A route for human exposure.
5) An exposed population.
ATSDR identifies exposure pathways as completed or potential.
No completed exposure pathways were identified because of the limited contamination concentrations off site. Workers on site are monitored for occupational exposure to radiological and hazardous materials.
Surface soils on and immediately around the RMI facility were likely contaminated by uranium dusts emitted from the plant's stacks between 1962 and 1990 when the facility ceased production. Fall out from the stacks emitting uranium dust was probably the major source of wurface soil contamination. However, surface soil runoff carrying uranium particulate also is suspected to have contributed to surface soil contamination. Surface soils contaminated with uranium have been identified and fenced off to prevent access to the public.
Releases of uranium into air took place from the middle of 1962 until 1989, emitting on average 0.3 Curies per year of uranium-238. The plant ceased air emissions of uranium in 1989 when uranium processing was curtailed. The airborne uranium dusts would not represent a past completed exposure pathway, as they were non-respirable (> 5 microns in diameter) and settled primarily on the roofs under the stacks and onto the ground on site. Air sampling data and deposition locations would indicate that the prevalent wind direction was from the west-southwest during plant operating hours. The primary exposed populations would have come from the among workers at the RMI site itself. The soil samples indicate that most of the uranium dusts settled out within 1/10 mile of the facility, and therefore were not accessible for inhalation by those downwind of the facility.
There is evidence of groundwater contamination with TCE on-site and has migrated beyond the site boundary, however, the area is fenced to prevent public access. The groundwater is not of sufficient quantity to be used and there are not drinking water wells within 1.5 miles of the site. Groundwater contamination is being remediated under a U.S. EPA RCRA corrective action. Since all water used in the area comes from Lake Erie this would not be a completed pathway.
There is no indication that surface water off site has been contaminated as a result of operations at RMI. However, this does not say anything about contamination of Fields Brook by any other party. Without any new data to the contrary, ATSDR must assume that Fields Brook is still contaminated at levels discussed in the Public Health Assessment for Fields Brook, and that it constitutes a potential pathway.
Levels of exposure to uranium and all other contaminants from the RMI facility are significantly below the levels known to cause measurable health effects, and because of the fact that there were no known exposed populations off site, it is not possible to directly attribute any adverse health outcomes to contaminants from RMI.
Uranium acts primarily as a renal toxin; that is to say, it damages the kidneys and inhibits the body's ability to remove wastes from the bloodstream. If there were a completed pathway for uranium, one would expect to see an excess of people with impaired kidney function or kidney damage.
Based on the available data (ANNUAL ENVIRONMENTAL REPORTS for RMI Plant), only one potential exposure pathway appears to exist in association with the RMI Extrusion Plant, but the levels of soil contamination are too low to pose a significant health risk. Even assuming a conservative estimate for incidental ingestion by a child, it would not appear to present a human health risk from a radiological standpoint. For a conservative estimate, we may assume that a child could ingest 200 milligrams of contaminated soil per day. That could result in the uptake of roughly 46 pCi of uranium per day, which for 365 days per year would yield 0.034 µCi of intake per year. The Annual Limit on Intake (ALI) of uranium-238 for occupational exposure is 200 µCi per year for the statistically standard adult American male, who weighs 70 kilograms. For a child weighing 25 kilograms, the ALI would be divided by a factor of 10 for non-occupational exposure, and divided by a factor of two for their relative weight. The child's ALI would therefore be limited to only 10 µCi/yr . Since the most conservative model puts the possible uptake at least 350 times below the ALI, incidental ingestion of uranium-contaminated soil does not appear to present a human health risk from a radiological standpoint.
The Lowest Observed Adverse Effect Level (LOAEL) is the level of dosage at which no adverse effects can be observed. There are three types of LOAELs, one for acute doses administered for less than 15 days, an intermediate value for doses administered for 15 to 364 days, and another for chronic doses received for more than a year.
If we also look at the chemical toxicity of uranium, we can find that the lowest chronic LOAEL is from an animal study on dogs . Uranium acts primarily as a renal toxin; that is to say, it damages the kidneys and inhibits the body's ability to remove wastes from the bloodstream. The level given for mild renal effects was 9.4 mg/kg/day. For a conservative estimate of the corresponding human No Observed Adverse Effect Level (NOAEL), we divide by a factor of 1000, giving an estimated value of 0.0094 mg/kg/day. The U.S. Environmental Protection Agency (EPA) sets the safe daily intake (RfD) even lower for uranium at 0.003 mg/kg of body weight per day. For a child weighing 25 kg, this corresponds to 0.075 mg soluble uranium per day. Since the specific activity of depleted uranium is 0.36 µCi/g (per 10 CFR 20 Appendix B), this gives a safe daily intake from a toxicological standpoint of 27 pCi per day of soluble uranium. The absorption of uranium metal and oxide forms in the gastrointestinal tract is only 0.2 percent: a small child could ingest 13,500 pCi/day of depleted uranium. At the maximum concentration found off site (463 pCi/g), this would mean the child would need to ingest in excess of 29 grams per day of maximally-contaminated soil to exceed any health guideline.
The sources of one past potential pathway were the exhaust stacks that emitted uranium dusts into the air from 1962 until 1989. Perimeter measurements for airborne uranium have consistently shown levels that are 1000 times lower than the Derived Air Concentration (DAC) limit of 3 x 10-10 µCi/ml. The Derived Air Concentration (DAC) is the concentration of a radionuclide in air which, if breathed alone for one work year, would irradiate the Reference Man to the limits of occupational exposure. The DAC equals the ALI of a radionuclide divided by the volume of air inhaled by the Reference Man in a working year (i.e., 2.4 x 103 m3). For an exposed non-occupational worker, the DAC limit would be reduced by a factor of 10 to 3 x 10-11 µCi/ml. This still puts emissions at the site perimeter at roughly 1/100th of that allowed.
The Ohio Department of Public Health, Division of Epidemiology, in 1988 completed an epidemiological study of cancers associated with the Fields Brook NPL Site . A draft version of the study concluded there was a slight excess of brain and central nervous system cancer in the area around Fields Brook NPL site. The final document found no evidence for excess cancer mortalities associated with the Fields Brook site, and concluded that the preliminary finding was due to miscategorization of other causes of death and birth defects.
Since levels of exposure to uranium from the RMI facility are significantly below the levels known to cause measurable health effects and due to the fact that there were no known exposed populations off site, it is not possible to directly attribute any adverse health outcomes to contaminants from RMI.
ATSDR has addressed each of the community concerns about health as follows.
1. Are there any radionuclides present at Fields Brook that would pose a health hazard to local school children passing through the area or to elderly persons at the local retirement home, paying particular attention to uranium, transuranics and fission products?
Evaluation of the data available does not indicate that anyone has been or will be exposed to levels of contamination that would be expected to cause any adverse health effects. There are no community-specific health outcome data available to indicate that the RMI facility has had any adverse effect on human health. Also, there are no transuranics at the site, and the only fission product is not at a level of health concern.
2. Should signs warning of radiation and radioactive material be posted along Fields Brook to the west of State Route 11?
Title 10 of the Code of Federal Regulations, Part 20 (10 CFR 20), requires that only those areas be restricted and posted where access would result in a dose rate of 50 mrem per year to the public. Because there is no radiological hazard from the area around the facility, it would not be advisable to post radiation hazard signs.
3. Is RMI considered a significant emitter of radionuclides as suggested by the EPA Draft Environmental Impact Statement for Proposed NESHAPS for Radionuclides (EPA 520/1-89-006-1)?
No. The RMI facility was removed from the final NESHAPS document (Federal Register # 54FR51654). In addition, RMI has ceased uranium extrusion operations and has not emitted radionuclides into the environment since 1989 when DOE operations ceased.
4. Is there any evidence that an employee at RMI suffered adverse health effects from exposure to radioactive materials at the plant?
There was insufficient evidence presented to conclude that any of the workers' adverse health effects correspond with any known for uranium exposures, however they may be consistent with other work related exposures. The cited adverse health outcomes could be related to work practices or processes used in the fabrication of uranium metal, but not directly from the uranium itself. The referenced document mentions toxic oil syndrome in passing .
5. Is there any risk from incineration of sediments dredged from Fields Brook?
Ongoing Fields Brook investigations have demonstrated that uranium is not a significant contaminate in Fields Brook sediments and therefore there are no radiological concerns relative to incineration of the sediments. Table 4 (page 9) indicates that uranium concentrations in Fields Brook sediments for 1987 and 1988 were significantly below the NRC guideline of 35 pCi/g and therefore is not a significant radiological concern in Fields Brook sediment.