COASTAL RADIATION SERVICES
ST. GABRIEL, IBERVILLE PARISH, LOUISIANA
On January 22, 2003, Jennifer Lyke, Regional Representative for the Agency for Toxic Substances and Disease Registry (ATSDR) in Region 6, contacted ATSDR's Division of Health Assessment and Consultation on behalf of The United States Environmental Protection Agency (EPA). A former radiation services company (Coastal Radiation Services) located in Iberville Parish, Louisiana, has contaminated six properties.
The U.S. Environmental Protection Agency (EPA) and the Louisiana Department of Environmental Quality (LDEQ) are working together to remove contamination problems at the Coastal Radiation Services (CRS) Site located at 6745 Bayou Paul Rd., in St. Gabriel, Iberville Parish Louisiana.
EPA has supplied new radiation survey data on two of the homes. EPA requests that ATSDR perform a follow-up to its consultation dated November 12, 2001, in light of new data.
On January 13-17, 2003, EPA Region 6 personnel conducted a radiological survey of floors located inside two homes located in the remedial site. The survey was a follow-up to a survey conducted October 17-19, 2001. Two adults and one child plan to reoccupy residence #1 after removal actions are complete. Residence #2 is currently occupied by two adults and is frequented by children on a regular basis.
During the survey, wipe samples were taken from areas with elevated radiation survey meter readings. Subsequent analysis of the wipe samples measured no removable contamination and determined that the contamination was fixed in place.
Survey instruments used were a Berkley Nucleonics Corp. SAM model 935C with a PN6895 probe for gamma measurements and to identify the contamination, and an Eberline E600 radiation survey meter with an Eberline SHP360 probe for beta measurements. Survey instruments were calibrated as required by the regulatory agencies and their survey teams. The radiation measurements were at contact or near contact measurements, typically a centimeter from the source.
Table 1 Lists locations and radiation measurements for residences 1 and 2 as well as the ATSDR estimates of the exposure rates at one meter and the external radiological dose the residents might receive at these locations.
|Location||cpm beta||µR/hr at 1 cm||Estimated Dose Rate at 1 meter (ÁR/hr)||Estimated Annual Dose above Background (mrem)|
|Residence #1 BR1 H1||400||1||0.0001||0.001|
|Residence #1 BR1 H2||400||1||0.0001||0.001|
|Residence #1 BR1 H3||250||1||0.0001||0.001|
|Residence #1 BR1 H4||300||1||0.0001||0.001|
|Residence #1 BR1 H5||600||7||0.0007||0.006|
|Residence #1 BR1 H6||38000||28||0.0028||0.025|
|Residence #1 BR1 H7||4000||4||0.0004||0.004|
|Residence #1 BR1 H8||2000||5||0.0005||0.004|
|Residence #1 BR1 H9||200||2||0.0002||0.002|
|Residence #1 BR1 H10||500||40||0.0040||0.035|
|Residence #1 BR1 H11||1000||6||0.0006||0.005|
|Residence #1 BR1 H12||500||2||0.0002||0.002|
|Residence #1 BR1 H13||200||37||0.0037||0.032|
|Residence #1 BR1 H14||600||3||0.0003||0.003|
|Residence #2 LR1 1L||400||1||0.0001||0.001|
|Residence #2 LR1 2L||500||6||0.0006||0.005|
|Residence #2 LR1 3L||250||4||0.0004||0.004|
|Residence #2 LR1 4L||500||15||0.0015||0.013|
|Residence #2 LR1 5L||1500||9||0.0009||0.008|
|Residence #2 LR1 6L||200||3||0.0003||0.003|
|Residence #2 LR1 7L||200||25||0.0025||0.022|
|Residence #2 LR1 8L||1000||8||0.0008||0.007|
|Residence #2 LR1 9L||1000||11||0.0011||0.010|
|Residence #2 LR1 10L||600||1||0.0001||0.001|
|Residence #2 LR1 11L||1000||10||0.0010||0.009|
|Residence #2 LR1 12L||300||9||0.0009||0.008|
|Residence #2 LR1 13L||200||7||0.0007||0.006|
|Residence #2 LR1 14L||400||20||0.0020||0.018|
|Residence #2 LR1 15L||500||2||0.0002||0.002|
|Residence #2 LR1 16L||2000||15||0.0015||0.013|
|Residence #2 LR1 17L||1000||20||0.0020||0.018|
|Residence #2 LR1 18L||350||2||0.0002||0.002|
|Residence #2 Hall 1H||4800||32||0.0032||0.028|
|Residence #2 BR2 1B2||1500||6.5||0.0007||0.006|
Based on the results of the survey, the contamination was identified as cesium 137.
Contact gamma exposure measurements (i.e., net gamma) are presented in Table 1. The annual whole body doses were estimated by assuming point sources of contamination at 1 centimeter and extrapolating to 1 meter distance (inverse square relationship), then multiplying by 24 hours per day 365 days per year.
The highest annual dose in Residence #1 was 0.035 millirem per year. The highest annual dose in Residence #2 was 0.028 millirem per year. This compares to an annual background dose of 100 millirem. In reality the dose from the cesium 137 contamination will be significantly lower than that estimated and are none the less insignificant.
- The radiation dose estimates to the whole-body and associated risks for Residences 1 and 2 are below the ATSDR Minimal Risk Level of 100 millirem per year above background. The dose estimates are also below any existing federal regulation that limits public exposure to radiation. Therefore, the estimated radiation doses do not represent a public health hazard.
- The ingestion and inhalation radiation dose estimates and associated risks for Residences 1 and 2 are also remarkably small, since the contamination is fixed, and do not represent a public health hazard.
- Residences 1 and 2 are safe for adults and children to live in.
- In light of the new survey data, this consultation supercedes recommendations of the prior health consultation.
- No remediation or removal of contamination is necessary for Residences 1 or 2.
Michael D. Brooks, CHP
Division of Health Assessment and Consultation
Paul Charp, Ph.D.
Senior Health Physicist
Division of Health Assessment and Consultation
U.S. Environmental Protection Agency (Region 6). Interim Removal Assessment Report for Coast Radiation Services. Dallas, Texas: 2001 November.
ATSDR Health Consultation for Coastal Radiation Services, Nov. 12, 2001