WIPP Enviornmental Monitoring Project

Project Concept

As defined in the original grant, the purpose of the WIPP EM project is to establish and maintain independent environmental research and monitoring in the vicinity of the WIPP and to make the results easily accessible to all interested parties. This project was implemented during the WIPP pre-disposal phase, and is now continuing during the operational (disposal) phase. The WIPP EM project is organized and carried out independent of direct oversight by DOE, and the project does not provide data to any regulatory body to meet the compliance demonstration requirements applicable to the WIPP. Analytical results and interpretations from the WIPP EM are published by CEMRC without prior review by DOE.

A detailed description of the WIPP EM concepts, sampling design and baseline studies is presented on the CEMRC web page. The following is a brief summary of 1999-2000 activities for each major environmental medium in the WIPP EM. Mixed waste was first received by the WIPP on 9 September 2000. Since results summarized in this report cover samples collected through June 2000, the results for non-radiological constituents are a continuation of baseline sampling.

Based on the radiological analyses of monitoring phase samples (collected since 26 March 1999) completed to date for area residents and for selected aerosols, soils, drinking water and surface water, there is no evidence of increases in radiological contaminants in the region of the WIPP that could be attributed to releases from the WIPP. In most cases, levels measured in 2000 were within the range of baseline levels measured by CEMRC for the targeted analytes.

Aerosols

Aerosol sampling is conducted at four locations, with samplers operating continuously at each location. The locations include a port inside the WIPP exhaust shaft, a site approximately 0.1 km northwest (downwind) of the WIPP exhaust shaft (On Site station), a site approximately 1 km northwest (downwind) of the WIPP (Near Field station) and a site approximately 19 km southeast (upwind) of the WIPP (Cactus Flats station) (Fig. 2).

Continuous sampling of aerosols was conducted through June 2000 using the same instruments, frequencies and locations as were previously established in the baseline phase. Analyses of all aerosol samples collected through June 2000 for both radiological and non-radiological constituents were completed and are reported herein. Web site posting of results of radiological and non-radiological analyses of aerosol samples collected in the WIPP exhaust shaft (FAS) began in July 1999, and are updated weekly. A summary of these data is also presented herein.

During the period July 2000 - June 2001, minor changes are being implemented to improve the aerosol sampling design. These changes include (1) standardizing the height of all sampler intakes at the On Site, Near Field and Cactus Flats stations to 4.3 m, with > l m between sampler intakes and underlying solid surfaces, (2) addition of a high volume TSP sampler at a location approximately 55 km northeast of the WIPP site, in Hobbs, New Mexico, (3) elimination of collection of PM_2.5 and PM₁₀ low-volume samples for inorganic analyses, and (4) modification of low-volume sample collection periods from two, two-day and one three-day cycle each week, to one three-day and one four-day cycle each week.

Soils

Soil sampling is conducted within a 166 km² area centered on the WIPP operations facility, and at a comparable area encompassing the Cactus Flats aerosol sampling station. Within each of these two areas, samples are collected at 16 locations positioned in concentric rectangular grids (Fig 2). For baseline studies at each of the 16 locations in each area, samples were collected during 1998 and 1999 at three randomly selected sites within a 50-m x 50-m area centered on the location's reference point. The resulting data represented 96 discrete samples that provided estimates of variability at the small-scale (between samples within a 0.0025 km² area), medium-scale (among locations within each 166 km² area) and large-scale (between the two sampling areas located approximately 19 km apart).

During 2000, one soil sample was collected at each of the 32 locations during January-February. The limitation of soil sampling to one period annually is based on the assumption that any input of contaminants to surface soils from WIPP releases would occur via aerosol deposition, and since aerosol sampling is conducted continuously, more frequent soil sampling is not warranted unless there was evidence of a contaminant increase in aerosols.

Surface Water and Sediments

The WIPP EM incorporates studies at three reservoirs on the Pecos River, which is the major perennial fresh water system closest to the WIPP that has extensive human usage. The three reservoirs are (1) Brantley Lake, located approximately 64 km northwest of the WIPP, (2) Lake Carlsbad, located in Carlsbad and approximately 40 km northwest of the WIPP and (3) Red Bluff Lake, located approximately 48 km southwest of the WIPP. Results of preliminary studies of selected radionuclides in sediments from Brantley Lake were reported in the CEMRC 1997 Report, and radioanalyses of sediment and surface water samples from all three lakes were reported in the CEMRC 1998 Report. The CEMRC 1999 Report contained results of analyses of the 1999 surface water and sediment samples for non-radiological constituents, analyses of selected alpha-emitting radionuclides in 1998 (baseline) sediment samples, and tests for Pu in 1998 surface water samples.

Radiological analyses of 2000 (monitoring phase) surface water samples were completed and are reported herein. Radiological analyses of 1999 and 2000 sediment samples are in progress and will be reported on the CEMRC web site when completed.

Because of the distance between the WIPP site and these reservoirs, the potential risk of direct contamination of the reservoirs by releases from the WIPP is relatively low compared to other media, and sampling in subsequent years will continue to be conducted once annually in the summer.

Drinking Water

The WIPP EM studies of ground water focus on the major drinking water supplies used by communities in the WIPP region because these are often perceived by the public as a potential route for contaminants to reach humans. Five community supplies of drinking water (representing three major regional aquifers) are included in routine sampling, including Carlsbad, Loving/Malaga, Otis, Hobbs and a secondary source for Carlsbad. One private water well (representing a fourth aquifer) that is located within 16 km of the WIPP is also sampled.

During initial baseline studies during 1996-1998, drinking water samples were subjected to analyses for over 150 analytes, including those that are regulated under the Safe Drinking Water Act, and contaminants known or suspected to be present in the WIPP wastes. Radioanalyses of drinking water conducted during 1997-1998 (previously reported) were unable to detect Pu or Am in any of the samples collected, using traditional alpha spectrometry. Subsequent analyses by thermal ionization mass spectrometry (TIMS) (a more sensitive radioanalytical technique) were also unsuccessful in detecting Pu in any of the water samples. Based on these results, subsequent radiological analyses have applied standard alpha spectroscopy detection limits achievable with 3-L samples. During 2000, drinking water samples were collected in the spring, and results of radiological and non-radiological analyses are reported herein. The six drinking water supplies will continue to be sampled once annually for selected radiological and inorganic testing.

Biota

Studies of biota for the WIPP EM have focused on native vegetation because the vegetation is consumed by beef cattle, and consumption of beef from cattle pastured in the vicinity of the WIPP could serve as an exposure pathway to humans for contaminants released from the WIPP. During baseline studies, vegetation samples were collected from a total of six species of plants that serve as preferred forage species for cattle during at least some portion of the year. During 1997-1998 baseline studies, vegetation was sampled twice annually during the two major periods of new growth for native vegetation (March-May and August-October). Six samples of each of three species (contingent on availability) were collected during each sampling period from selected sites on the sampling grid surrounding the WIPP (which encompasses the Near Field aerosol sampling station). During late summer 1999, the first monitoring phase samples were collected, consisting of a single sample of several grass species from each of the 32 soil sampling locations.

Radiochemical analyses of the baseline and initial monitoring phase samples will be carried out during 2001, followed by web page posting and inclusion in the CEMRC 2001 Report. No additional vegetation sampling is planned to be conducted until spring 2002.

Additional studies are planned to evaluate the effectiveness of expanding the biota sampling for radionuclides to include arthropods. Arthropods were collected at the Cactus Flats station during spring through fall in 1998 (baseline) and at Near Field and Cactus Flats stations during spring through fall in 1999. Comparative radioanalyses of the samples are planned during 2001 to evaluate the effectiveness of this environmental component in long-term monitoring.

Human Population

The "Lie Down and Be Counted" (LDBC) project serves as a component of the WIPP EM that directly addresses the general concern about personal exposure to contaminants shared by residents who live near DOE sites. As in other aspects of the WIPP EM, in vivo bioassay testing was used to establish a baseline profile of internally-deposited radionuclides in a sample of local residents. The sampling design includes solicitation of volunteers from all segments of the community, with sample sizes sufficient to meet or exceed a 15% range in margin of error for comparisons between major population ethnicity and gender categories as identified in the 1990 census. The minimum sample size threshold was achieved for the major categories early in 1998, and continued baseline sampling resulted in radiobioassays completed for 367 individuals before the first receipt of waste at the WIPP, reducing margin of error ranges to a maximum of 5-7% for any category. Radiobioassays of the original volunteer cohort began in July 1999 to achieve a complete cohort recount by July 2001. New volunteers will continue to be recruited each year, with a target of 100 new volunteers annually to establish new study cohorts and replacement of volunteer attrition.

Results of the LDBC project through 1 October 2000 are reported herein, and are updated quarterly on the CEMRC web site.

Meteorological Monitoring

Fully automated meteorological stations are operated by the CEMRC at the Near Field aerosol station and the Cactus Flats aerosol station. Details concerning the sensors and operation of the equipment and a summary of the last year's meteorological patterns are presented herein.

Management of WIPP EM Project

The scheduling and management of sample analyses collected in the WIPP EM project are based on (1) priorities for providing information to the public in a timely manner, (2) relative risks of human exposure to contaminants among the various media sampled, (3) needs for stringent data validation and verification prior to release and (4) time constraints resulting from sample preparation and analysis procedures.

The management plan for the WIPP EM incorporates milestones representing significant products and progress, including both routine sampling and analyses and special studies. Key performance indicators that integrate groups of milestones are identified and reviewed annually to serve as metrics of the successful progress of the project. Completion of 2000 key performance indicators is summarized in Appendix I. Eleven indicators were completed on time and four indicators were delayed but completed prior to year-end. Four out of 19 indicators were not completed, with 0-90% progress on each. Key performance indicators for 2001 have been identified to serve as the basis for the 2001 WIPP EM project schedule (Table 2)

Table 2. Key Performance Indicators for 2001