Savannah River Site Health Effects Subcommittee (SRSHES) Meeting

Meeting Minutes
September 5, 2002

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Mr. Bob Lorenz, of the Westinghouse Savannah River Company (WSRC), reported that SEMP was established in 1953 and is implemented under four guiding principles: a comprehensive database of SRS environmental monitoring data collected since the early 1950s; an annual review to ensure correct media and frequencies are evaluated; a thorough knowledge of types and quantities of releases; and a clear understanding of dose impacts to the public. Baseline studies of environmental monitoring activities were completed in 1951-1952 by the U.S. government and private companies. SEMP is designed as a living program that is updated and refined each year.

The U.S. Department of Energy (DOE) and WSRC have institutionalized an environmental philosophy to conduct SEMP. The components of this concept include zero violations; full compliance with all state and federal regulations; the "as low as reasonably achievable" (ALARA) principle; and open communication, data exchange and regular meetings with the public and state agencies in both Georgia and South Carolina. The Environmental ALARA Committee periodically meets to review past and planned releases with all facility representatives and ensure goals have been met. ALARA performance measures are published and distributed to each facility in a monthly internal report.

For purposes of SEMP, "effluent monitoring" is defined as the collection of samples or data from the point at which a facility discharges liquid or gaseous releases to the environment. "Environmental surveillance" is the collection of samples or data from air, water, soil, foodstuffs, biota and other media from the ambient environment. SEMP's goals are to characterize and quantify contaminants, demonstrate compliance with applicable standards, calculate radiation exposures to the public, and assess any effects on the local environment. In 2001, 12,000 samples were collected and 30,000 analyses were performed by SEMP for several environmental media, including ambient air, deer, drinking water, fish, food products, hogs, rainwater, sediment, soil, surface water and vegetation.

SEMP evaluates all contaminant pathways that may affect the public at the following locations: the building, sand filter, stack, area fence, site perimeter, 25-mile radius and 100-mile radius. Several surveillance programs have been established under SEMP to assess contaminant pathways. In the Air Monitoring Program, areas are selected for evaluation based on population size and most probable wind direction. Offsite air monitoring stations are located in Aiken, South Carolina; Augusta, Georgia; Highway 301 Welcome Center, Georgia; and Savannah, Georgia; 12-14 air stations have been placed around the perimeter of the site. Air monitoring samples are collected and analyzed for tritium, particulate matter, iodine, plutonium, cesium, other ions of interest and all other radionuclides. With the exception of collecting fish samples and conducting special studies, organically-bound tritium (OBT) is not routinely measured by SEMP at this time.

In the Liquid Effluent Monitoring Program, continuous water flow, water concentrations and rainwater are measured. Air and liquid effluent samples are alternately analyzed on a weekly, biweekly or monthly basis, but all stations are monitored each week to ensure proper operation. SEMP has the capability to gather a composite or average sample over a certain period of time and the ability to collect a sequential sample to pinpoint releases in a particular time span. As a result of the December 1991 tritium release at SRS, SEMP established the Enhanced Tritium Monitoring Program (ETMP) to undertake three major tasks.

First, tritium discharged from SRS to the Savannah River is monitored by measuring concentrations at onsite stream locations. Second, river concentrations are calculated based on steam data from the RM-129 location. Third, timely notification is provided to down-river consumers of significant changes in Savannah River tritium levels. Samples are collected from ETMP three times a week, but the number of tritium source terms declined as operations ceased in certain locations over the past ten years. However, tritium is still released from the Effluent Treatment Facility that discharges to Upper Three Runs Creek. SEMP ensures that tritium concentration levels at Savannah River are maintained below 5,000 pCi/L.

The drinking water standard has been established at 20,000 pCi/L per day for 365 consecutive days. A tritium sampler has been placed south of the Plant Vogtle Nuclear Generating Station as well. Although SEMP has measured several peaks in tritium levels, discharges and transport to the Savannah River as well as tritium concentrations in drinking water have dramatically decreased overall. In the Fish Monitoring Program, samples are collected from 15 bass, 15 brim and 15 catfish from ten locations each year. Both saltwater and freshwater fish are caught since fish are a significant contaminant pathway to humans. To date, elevated cesium, strontium and tritium levels have been detected in fish caught near the site.

In the Deer and Hog Monitoring Program, onsite hunts are conducted for 20 days each year from various selected areas; 1,500-1,800 deer and hogs are harvested per animal hunt. SEMP places counters on hogs and deer to detect cesium-137 and calculates dose by assuming a hunter will consume 45%-50% of the animal. If a hog or deer does not exceed the DOE standard of 100 mrem, SEMP allows hunters to move animals offsite. SEMP has only had to confiscate one animal since the program was established. In the Gamma Radiation Monitoring Program, detectors similar to those worn by onsite personnel have been placed at air monitoring locations in selected areas. Samples are collected and analyzed on a quarterly basis.

SEMP’s 2001 data showed that tritium was a major contributor to all contaminant pathways and accounted for 42% of airborne radionuclide releases, 51% of airborne doses, 99% of liquid radionuclide releases and 38% of liquid doses. Krypton-85 contributed to 58% of airborne radionuclide releases, but the low-dose fission product is a weak contributor to dose consequence. Cesium-137 was also a significant contributor to liquid dose due to high levels found in fish. In comparison to the DOE standard of 100 mrem per year for individual doses, individual doses to the offsite public in 2001 were calculated at 0.13 mrem for liquids and 0.05 mrem for air. In comparison to the U.S. Environmental Protection Agency (EPA) drinking water standard of 4 mrem per year, SRS drinking water standards were calculated at 0.07 mrem in Beaufort-Jasper, South Carolina and 0.06 mrem in Port Wentworth, Georgia.

In general, maximally exposed individual dose levels at SRS from 1990-2001 have been steady and low at a range of 0.28-0.18 mrem. In particular, sportsmen doses for onsite hunters and creek mouth fishermen at Upper Three Runs are calculated separately from other individuals. At 14 mrem for onsite hunters and 0.26 mrem for creek mouth fishermen, the 2001 SRS dose calculations were well below the DOE standard of 100 mrem per year. Overall, SRS airborne and liquid releases to the environment continue to decline.

The SEMP 2001 in-depth data results are included in the annual report. The document is currently being completed and should be distributed within the next ten days. The SEMP 2001 Annual Report will be disseminated on a CD-ROM; data tables and annual reports for the Environmental Restoration and Solid Waste Programs will be included on the CD-ROM as well. However, hard copies can be mailed to individuals upon request. The SEMP summary pamphlet has been finalized and is now available to the public.

Discussion.

Ms. Kato noted that beavers were not included in the list of environmental media from which samples are collected and analyses are performed by SEMP. Mr. Lorenz explained that beavers are considered "nuisance" animals and are not consumed by or released to hunters. Although beavers were previously monitored by SEMP, the sacrifice of these animals was found to be unnecessary since beavers would not play a role in dose consequence to persons. Ms. Guess asked if SEMP monitors locations that contain beaver ponds. She also inquired about the rationale for not placing a monitoring station at the bottom of Three Mile Creek.

To the first question, Mr. Lorenz confirmed that samples are collected from areas with beaver ponds since soil, fish, vegetation and sediment samples from streams are gathered from various locations. To the second question, he explained that a monitoring station has not been placed at Three Mile Creek because no source term exists below this sampling location. Mr. Lockridge asked about the probability of a short-term release occurring and traveling downstream before being detected in the weekly sample. Mr. Lorenz replied that the potential for this scenario is extremely low because ETMP tritium samples are collected and analyzed every three days.

Mr. Wills recalled that at the previous meeting, an onsite contractor informed SRSHES of contaminated water traveling to the Savannah River while workers removed beaver dams containing radionuclides. He inquired whether SEMP has collected these samples. Mr. Lorenz responded that no differences in Savannah River concentration levels have been detected as a result of contractors removing beaver dams. Ms. Drye questioned whether cumulative doses in the actual hunter is being monitored in addition to deer and hogs. Mr. Lorenz confirmed that SEMP tracks hunters to ensure doses do not exceed the annual standard of 100 mrem. However, the program is designed to evaluate levels in humans in a one-year period of time rather than a cumulative dose over a longer time span.

Mr. Lockridge announced that the issue of cumulative dose has been incorporated into the outdoors person scenario and will be presented to SRSHES for review and comment on the following day. Ms. Kato requested clarification on the "unidentified beta," "unidentified alpha" and "others" categories in the 2001 SRS dose calculations. She also inquired about SEMP’s methodology to translate curies into dose since the two units are not comparable. Overall, Ms. Kato expressed concern about the large amount of assumptions made in the SEMP data since only 10-12 sampling locations are operating offsite.

Mr. Lorenz noted that the generic categories for "all alpha" and "all beta" emitters were developed due to the extensive cost and time required to evaluate each radionuclide separately. Consequences for unidentified alpha or beta emitters are calculated as plutonium-239 or strontium-90 doses, respectively. Mr. Lorenz pointed out that the SEMP 2001 Annual Report contains a chapter detailing the conversion methodology, assumptions and models. As a co-author of the dose calculation section, Dr. Lee added that computer models were developed to convert releases to exposure. The calculations incorporated actual onsite meteorologic data from atmospheric dispersions, wind direction, humidity and other factors. Dr. Bustos recessed the meeting for a break from 10:30-11:04 a.m.