PNNL-12088
September 1999
This Hanford Site environmental report is prepared annually to summarize environmental data and information, to describe environmental management performance, to demonstrate the status of compliance with environmental regulations, and to highlight major environmental programs and efforts.
The report is written to meet requirements and guidelines of the U.S. Department of Energy (DOE) and to meet the needs of the public. This summary has been written with a minimum of technical terminology.
Individual sections of the report are designed to
More detailed information can be found in the body of the report, the cited references, and the appendixes.
The Hanford Site in southcentral Washington State is approximately 1,450 km2 (560 mi2) of semiarid shrub and grasslands located just north of the confluence of the Snake and Yakima Rivers with the Columbia River. This land, with restricted public access, provides a buffer for the smaller areas historically used for the production of nuclear materials, waste storage, and waste disposal. Approximately 6% of the land area has been disturbed, is actively used, and is divided into operational areas:
The 600 Area is the designation for land between the operational areas. Areas off the Hanford Site used for research and technology development and administrative functions can be found in Richland, Kennewick, and Pasco, the nearest cities.
The Hanford Site was acquired by the federal government in 1943 and, until 1989, was dedicated primarily to the production of plutonium for national defense and the management of the resulting wastes. With the shutdown of the production facilities in the 1970s and 1980s, missions were diversified to include research and development in the areas of energy, waste management, and environmental restoration.
DOE has ended the production of nuclear materials for weapons at the Hanford Site. The current mission being implemented by DOE Richland Operations Office is now:
Current waste management activities at the Hanford Site include primarily managing wastes with high and low levels of radioactivity (from the nuclear materials production activities) in the 200 East and 200 West Areas. Key waste management facilities include the underground waste storage tanks, Environmental Restoration Disposal Facility, Central Waste Complex, low-level burial grounds, 200 Areas Effluent Treatment Facility, Waste Receiving and Processing Facility, 242.A Evaporator, State-Approved Land Disposal Site, Liquid Effluent Retention Facility, and 200 Areas Treated Effluent Disposal Facility. In addition, irradiated nuclear fuel is stored in the 100 K Area in fuel storage basins.
Environmental restoration includes activities to decontaminate and decommission facilities and to clean up or restore inactive waste sites. The Hanford surplus facilities program conducts surveillance and maintenance of such facilities; the cleanup and disposal of more than 100 facilities have begun.
Research and technology development activities are intended to improve the techniques and reduce the costs of waste management, environmental protection, and site restoration.
Operations and activities on the site are managed by DOE Richland Operations Office through four prime contractors and numerous subcontractors. Each contractor is responsible for the safe, environmentally sound maintenance and management of its facilities and operations, management of its wastes, and monitoring of its operations and effluents for environmental compliance.
The principal contractors include the following:
Non-DOE operations and activities include commercial power production by Energy Northwest (formerly known as the Washington Public Power Supply System) at its WNP-2 Reactor and operation of a commercial low-level radioactive waste burial site by US Ecology, Inc. Kaiser Aluminum and Chemical Corporation leases the 313 Building to operate a formerly DOE-owned extrusion press. The National Science Foundation has built the Laser Interferometer Gravitational-Wave Observatory facility near Rattlesnake Mountain. R. H. Smith Distributing operates vehicle fueling stations in the former 1100 Area and the 200 Areas. Washington State University at Tri-Cities operates three laboratories in the 300 Area. Livingston Rebuild Center, Inc. leases the former 1171 Building in the former 1100 Area to rebuild train locomotives. Johnson Controls, Inc. operates 42 diesel and natural gas fueled package boilers for producing steam in the 200 and 300 Areas and also has compressors supplying compressed air to the site. Immediately adjacent to the southern boundary of the Hanford Site, Siemens Power Corporation operates a commercial nuclear fuel fabrication facility and Allied Technology Group Corporation operates a low-level radioactive waste decontamination, supercompaction, and packaging disposal facility.
DOE Order 5400.1, "General Environmental Protection Program," describes the environmental standards and regulations applicable at DOE facilities. These standards and regulations fall into three categories: 1) DOE directives; 2) federal legislation and executive orders; and 3) state and local statutes, regulations, and requirements. The following summarizes the status of Hanford's compliance with applicable regulations and lists the environmental occurrences for 1997.
A key element in Hanford's compliance program is the Hanford federal facility agreement and consent order (also known as the Tri-Party Agreement; Ecology et al. 1989). The Tri-Party Agreement is an agreement among the U.S. Environmental Protection Agency (EPA), Washington State Department of Ecology, and DOE for achieving compliance with the remedial action provisions of the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA 1980) and with treatment, storage, and disposal unit regulation and corrective action provisions of the Resource Conservation and Recovery Act (RCRA 1976). From 1989 through 1998, a total of 597 enforceable Tri-Party Agreement milestones and 246 unenforceable target dates were completed on or ahead of schedule. Fifty-eight milestones scheduled for 1998 were completed.
This act established a program to ensure that sites contaminated by hazardous substances are cleaned up by responsible parties or the government. The act primarily covers waste cleanup of inactive sites.
Preliminary assessments conducted for the Hanford Site revealed approximately 2,200 known individual waste sites where hazardous substances may have been disposed of in a manner that requires further evaluation to determine impact to the environment.
The DOE is actively pursuing the remedial investigation/feasibility study process at some operable units on the Hanford Site. The operable units currently being studied were selected as a result of Tri-Party Agreement negotiations.
In 1998, the Hanford Site was in compliance with requirements of the act. Cleanup is under way at various areas on the site. Full-scale remediation of waste sites continued in the 100 and 300 Areas in 1998.
This act requires that the public be provided with information about hazardous chemicals in the community and establishes emergency planning and notification procedures to protect the public from a release. The act calls for creation of state emergency response commissions to guide planning for chemical emergencies. State commissions have also created local emergency planning committees to ensure community participation and planning.
To provide the public with the basis for emergency planning, the act contains requirements for periodic reporting on hazardous chemicals stored and/or used near the community. The 1998 Hanford Site's emergency and hazardous chemical inventory was issued to the State Emergency Response Commission, local county emergency management committees, and local fire departments in February 1999. The inventory report contained information on hazardous materials in storage across the site. If required, a toxic chemical release inventory report is issued each year, which provides details regarding releases, offsite transfers, and source reduction activities involving any toxic chemicals used in excess of regulatory thresholds during the previous year. Reporting thresholds for phosphoric acid were exceeded in 1997, so a report was issued in June 1998. During 1998, the Hanford Site was in compliance with the reporting and notification requirements contained in this act.
This act establishes regulatory standards for the generation, transportation, storage, treatment, and disposal of hazardous wastes. The Washington State Department of Ecology has been authorized by EPA to implement its dangerous waste program except for some provisions of the Hazardous and Solid Waste Amendments of 1984. The Washington State Department of Ecology implements the state's regulations, which are often more stringent. The act primarily covers ongoing waste management at active facilities.
At the Hanford Site, over 60 treatment, storage, and disposal units have been identified that must be permitted or closed in accordance with the act and Washington State regulations. These units are required to operate under the Washington State Department of Ecology's interim-status compliance requirements. Approximately one-half of the units will be closed.
Subtitle I of the act deals with regulation of underground storage tank systems. These regulations were added to the act by the Hazardous and Solid Waste Amendments of 1984. EPA developed regulations implementing technical standards for tank performance and management, including standards governing the cleanup and closure of leaking tanks. These regulations do not apply to the single- and double-shell tanks, which are regulated as treatment, storage, and disposal facilities.
The purpose of this act is to protect public health and welfare by safeguarding air quality, bringing polluted air into compliance, and protecting clean air from degradation. In Washington State, the provisions of the act are implemented by EPA, Washington State Department of Ecology, Washington State Department of Health, and local air authorities.
Washington State regulations require applicable controls and annual reporting of all radioactive air emissions. The Hanford Site operates under a license for such emissions. The conditions specified in the license will be incorporated into the Hanford Site air operating permit, scheduled to be issued in 1999.
Revisions to the act for radioactive air emissions were issued in December 1989. Emissions from the Hanford Site are within the state and EPA offsite emissions standard of 10 mrem/yr. Nearly all Hanford Site sources currently meet the procedural requirements for flow measurement, emissions measurement, quality assurance, and sampling documentation.
The local air authority (the Benton Clean Air Authority) regulations pertain to detrimental effects, open burning, odor, opacity, and asbestos handling. The authority has also been delegated responsibility to enforce the EPA asbestos regulations under the revised act. The site remains in compliance with the regulations.
This act applies to point discharges to waters of the United States. At the Hanford Site, the regulations are applied through National Pollutant Discharge Elimination System permits that govern effluent discharges to the Columbia River. The permits specify discharge points (called outfalls), effluent limitations, and monitoring requirements. Several permit violations occurred at the 300 Area Treated Effluent Disposal Facility in 1998 despite the use of best available technology. An application to modify the facility's discharge permit has been submitted.
The National Primary Drinking Water Regulations of the Safe Drinking Water Act apply to the drinking water supplies at the Hanford Site and are enforced by the Washington State Department of Health. In 1998, all Hanford Site water systems were in compliance with requirements and agreements.
The application of this act's requirements to the Hanford Site involves regulation of the chemicals called polychlorinated biphenyls. The site is currently in compliance with an agreement to store these wastes beyond the regulatory limit. All radioactive polychlorinated biphenyl wastes are being stored pending development of treatment and disposal technologies and capabilities.
EPA is responsible for ensuring that a chemical, when used according to label instructions, will not present unreasonable risks to human health or the environment. This act and specific chapters of the Revised Code of Washington apply to storage and use of pesticides. In 1998, the Hanford Site was in compliance with these requirements.
Many rare species of native plants and animals are known to occur on the Hanford Site. Three of these (bald eagle, peregrine falcon, and Aleutian Canada goose) are listed by the U.S. Fish and Wildlife Service as endangered or threatened. Steelhead trout and spring chinook salmon are listed by the National Marine Fisheries Service. Other species are listed by the Washington State Department of Fish and Wildlife as endangered, threatened, or sensitive. Hanford Site activities complied with this act in 1998.
Cultural resources on the Hanford Site are subject to the provisions of these acts. In 1998, the Hanford Site was in compliance with these acts.
This act establishes environmental policy to prevent or eliminate damage to the environment and to enrich our understanding of ecological systems and natural resources. This act requires that major federal projects with significant impacts be carefully reviewed and reported to the public in environmental impact statements. Other documents such as environmental assessments are also prepared in accordance with requirements of the act.
Several environmental impact statements related to programs or activities on the Hanford Site are in process or in the planning stage.
Onsite and offsite environmental occurrences (spills, leaks) of radioactive and nonradioactive effluent materials during 1998 were reported to DOE and other federal and state agencies as required by law. All emergency, unusual, and off-normal occurrence reports, including event descriptions and corrective actions, are available for review in the DOE Hanford Reading Room located on the campus of Washington State University at Tri-Cities, Richland, Washington. There was one emergency occurrence report and one environmentally significant unusual occurrence report filed in 1998. There were several off-normal environmental release-related occurrence reports filed during 1998.
At the Hanford Site, contractors are in the process of implementing Integrated Environment, Health, and Safety Management Systems. These systems, contractually mandated by DOE, are intended to integrate environment, health, and safety into the way work is planned and performed, protecting the worker, public, and environment. The Integrated Environment, Health, and Safety Management System includes important aspects of an environmental management system. The international standard ISO 14001 for environmental management systems has been used to develop the system. Implementation of the Integrated Environment, Health, and Safety Management System constitutes implementation of the environmental management system. Current DOE direction calls for implementation of the Integrated Environment, Health, and Safety Management System by September 2000.
Radioactive, hazardous, and mixed waste is generated at approximately 200 facilities on the Hanford Site. These wastes are handled and prepared for safe storage on the site or shipped off the site for treatment and disposal. In addition to newly generated waste, significant quantities of waste remain from over 50 yr of nuclear material production. This waste from past operations at the Hanford Site resides in waste sites or is stored in several places awaiting cleanup and ultimate safe storage or disposal. Examples are high-level radioactive waste stored in single- and double-shell tanks and transuranic waste stored in vaults and on storage pads. Most of the environmental monitoring performed at the Hanford Site is focused on protecting the public from exposure to this waste and waste handling activities. See Section 2.5, "Waste Management and Chemical Inventories," for details.
Environmental monitoring of the Hanford Site consists of effluent monitoring, environmental surveillance, and groundwater and vadose zone monitoring. Effluent monitoring is performed as appropriate by the operators at the facility or at the point of release to the environment. Additional monitoring is conducted in the environment near facilities that discharge, or have discharged, effluents. Environmental surveillance consists of sampling and analyzing environmental media on and off the site to detect and quantify potential contaminants and to assess their environmental and human health significance.
The overall objectives of the monitoring and surveillance programs are to demonstrate compliance with applicable federal, state, and local regulations; confirm adherence to DOE environmental protection policies; and support environmental management decisions.
Effluent monitoring includes facility effluent monitoring (monitoring effluents at the point of release to the environment) and near-facility environmental monitoring (monitoring the environment near operating facilities).
Facility Effluent Monitoring. Liquid and gaseous effluents that may contain radioactive and/or hazardous constituents are continually monitored at the Hanford Site. The monitoring is done mainly by collecting effluent samples near points where the effluent is released into the environment. These samples are analyzed for selected constituents and the results evaluated against federal, state, and local regulatory standards and permit requirements.
Effluent stream flows are determined mostly through the use of measuring instruments, with a lesser number calculated using process information. Effluents with the potential of containing radioactivity that may reach prescribed threshold levels are monitored for gross alpha and gross beta activity and, as warranted, specific gamma-emitting radionuclides. When warranted, nonradioactive hazardous constituents are also monitored.
The radioactivity in effluents released from most Hanford facilities is at or near levels practically indistinguishable from naturally occurring radioactivity present everywhere in the world. Cumulatively, these low levels contribute very little to the radiation dose received by people living in areas surrounding the site.
Near-Facility Environmental Monitoring. The near-facility environmental monitoring program is designed to protect the environment adjacent to Hanford facilities and to ensure compliance with federal, state, and local regulations. Specifically, this program monitored new and existing sites, processes, and facilities for potential impacts and releases; fugitive emissions and diffuse sources from contaminated areas; and surplus facilities before decontamination or decommissioning. Air, surface water, springs, surface contamination, soil, vegetation, external radiation, and investigative sampling (which can include wildlife) were sampled. Some of the parameters typically monitored are pH, radionuclide activities, radiation exposure levels, and concentrations of selected hazardous chemicals. Samples are collected from known or expected effluent pathways. These pathways are generally downwind of potential or actual airborne releases and downgradient of liquid discharges.
Near-Facility Air Monitoring. Radioactivity in air was sampled by a network of continuously operating samplers at 71 locations near nuclear facilities. Air samplers were primarily located within approximately 500 m (1,500 ft) of sites and/or facilities having the potential for, or history of, environmental releases, with an emphasis on the prevailing downwind directions. Of the radionuclide analyses performed, strontium-90, cesium-137, plutonium-239,240, and uranium were consistently detected in the 100-K, 100 N, and 200 Areas. Cobalt-60 was consistently detected in the 100 N Area. Air levels for these radionuclides were elevated near facilities compared to the levels measured off the site.
Surface-Water Disposal Units and 100-N Springs Monitoring. Samples collected from surface-water disposal units (ponds, ditches) included water, sediment, and aquatic vegetation. Only water samples were taken at 100-N Area shoreline springs. Radiological analyses of water samples from surface-water disposal units included strontium-90, plutonium-238, plutonium-239,240, uranium, tritium, and gamma-emitting radionuclides. Radiological analyses of sediment and aquatic vegetation samples were performed for strontium-90, plutonium-239,240, uranium, and gamma-emitting radionuclides. Nonradiological analyses were performed for pH, temperature, and nitrates.
When liquid samples from surface-water disposal units in the 200 Areas were analyzed for radionuclides, the results were less than the DOE derived concentration guides and, in most cases, were equal to or less than the analytical detection limits. Although some elevated levels were seen in both aquatic vegetation and sediment, in all cases, the analytical results were much less than the standards used for radiological control. The results for pH were well within the 2.0 to 12.5 pH standard for liquid effluent discharges based on the discharge limits listed in the Resource Conservation and Recovery Act. The analytical results for nitrates were all less than the 45.mg/L EPA drinking water standard for public water supplies.
Groundwater springs along the 100-N Area shoreline are sampled annually to verify the reported radionuclide releases to the Columbia River from past N Reactor operations. By characterizing the radionuclide activities in the springs along the shoreline, the results can be compared to the activities measured at the facility effluent monitoring well. In 1998, the radionuclide activities detected in samples from shoreline springs were highest in springs nearest the effluent monitoring well.
Near-Facility Radiological Surveys. In 1998, there were approximately 3,641 ha (8,997 acres) of posted outdoor contamination areas and 587 ha (1,450 acres) of posted underground radioactive materials areas, not including active facilities, at the Hanford Site. These areas were typically associated with burial grounds, covered ditches, cribs, and tank farms. The posted contamination areas vary between years because of an ongoing effort to clean, stabilize, and remediate areas of known contamination. During this time, new areas of contamination were being identified. It was estimated that the external dose rate at 80% of the identified outdoor contamination areas was less than 1 mrem/h measured at 1 m (3.28 ft), though direct dose rate readings from isolated radioactive specks (a diameter of less than 0.6 cm [0.25 in.]) could have been considerably higher. Contamination levels of this magnitude did not significantly add to dose rates for the public or Hanford Site workers in 1998.
Soil and Vegetation Sampling from Operational Areas. Soil and vegetation samples were collected on or adjacent to waste disposal units and from locations downwind and near or within the boundaries of the operating facilities. Samples were collected to detect potential migration and deposition of facility effluents. Special samples were also taken where physical or biological transport problems were identified. Migration can occur as the result of resuspension from radioactively contaminated surface areas, absorption of radionuclides by the roots of vegetation growing on or near underground and surface-water disposal units, or by waste site intrusion by animals. Some radionuclide activities in soil and vegetation samples from near facilities were elevated when compared to activities measured off the site. The levels show a large degree of variance; in general, samples collected on or adjacent to waste disposal facilities had significantly higher radionuclide activities than those collected farther away.
Near-Facility External Radiation. External radiation fields were measured near facilities and waste handling, storage, and disposal sites to measure, assess, and control the impacts of operations.
Four new thermoluminescent dosimeter monitoring sites were established in the 100-B,C Area during late 1998 to evaluate environmental restoration activities at the 116-B-11 Water Retention Basin and the 116-C-1 Liquid Waste Disposal Trench. The 1998 average was comparable to offsite background levels.
Five thermoluminescent dosimeter locations were established in the 100-D,DR Area during late 1996 to evaluate environmental restoration activities at the 116-D-7 and 116-DR-9 Water Retention Basins. The 1998 readings were comparable to offsite background levels.
This is the sixth year that thermoluminescent dosimeters have been placed in the 100 K Area, surrounding the 105-K East and 105-K West Fuel Storage Basins (K Basins) and adjacent reactor buildings. Dose rates decreased noticeably in 1998 as the result of the removal of stored radioactive waste.
At the 100-N Area, the 1998 thermoluminescent dosimeter results indicate that direct radiation levels were again highest near facilities that had contained or received liquid effluent from N Reactor. These facilities primarily include the 1301-N and 1325-N Liquid Waste Disposal Facilities. Although the results for these two facilities were noticeably higher than those for other 100-N Area thermoluminescent dosimeter locations, they were approximately 17% lower than exposure levels measured at these locations in 1997. Eight dosimeters that were located in low background areas were removed from the network in 1998, which caused an artificial 22% overall annual average increase.
The highest dose rates in the 200/600 Areas were measured near waste handling facilities such as tank farms. The highest dose rate was measured at the A Tank Farm complex (200 East Area). The average annual dose rate in the 200 Areas measured in 1998 was 104 mrem/yr, approximately 5% lower than the dose rate measured in 1997.
Two thermoluminescent dosimeter locations were established at the Environmental Restoration Disposal Facility during late 1996 to evaluate the disposal activities in progress. Readings in 1998 were comparable to offsite background levels.
The highest dose rates in the 300 Area were measured near installations such as the 340 Waste Handling Facility. The average annual dose rate measured in the 300 Area in 1998 was 110 mrem/yr, equal to the average measured in 1997. The average annual dose rate at the 300 Area Treated Effluent Disposal Facility in 1998 was 82 mrem/yr, a slight increase (1%) relative to the average dose rate measured in 1997.
The average annual dose rate measured in the 400 Area in 1998 was 84 mrem/yr, a decrease of 2% compared to the average dose rate measured in 1997.
Investigative Sampling. To confirm the absence or presence of radioactive or hazardous contaminants, or to verify radiological conditions at specific project sites, investigative samples were collected from across the Hanford Site in 1998.
Generally, the predominant radionuclides discovered during these efforts were activation products in the 100 and 200 Areas, and uranium in the 300 Area. Hazardous chemicals generally have not been identified above background levels in preoperational environmental monitoring samples.
Investigative samples in 1998 included soil, vegetation, nests, mammal feces, insects, and wildlife. The samples were collected where known or suspected radioactive contamination was present or to verify radiological conditions at project sites. In 1998, 51 samples were analyzed for radionuclides, and 50 showed some level of contamination. In addition, 133 samples were collected and disposed of without isotopic analyses, though field instrument readings were recorded.
Environmental surveillance at the Hanford Site includes monitoring environmental media on and off the site for potential chemical and radiological contaminants originating from site operations. The media monitored included air, surface water and sediment, drinking water, food and farm products, fish, wildlife, soil, vegetation, and external radiation.
Air Surveillance. Radioactivity in air were monitored at 39 continuously operating onsite locations, at the Hanford Site perimeter, and in nearby and distant communities. Nine of these locations were community-operated environmental surveillance stations that were managed and operated by local school teachers. At all locations, particulates were filtered from the air and analyzed for radionuclides. Air was sampled and analyzed for selected gaseous radionuclides at key locations. Several radionuclides released at the Hanford Site are also found worldwide from two other sources: naturally occurring radionuclides and radioactive fallout from historical nuclear activities not associated with Hanford operations. The potential influence of emissions from Hanford Site activities on local radionuclide activities was evaluated by comparing differences between levels measured at distant locations within the region and levels measured at the site perimeter.
In 1998, the site perimeter annual average gross alpha air concentration was slightly higher than the distant community location concentrations. There were no differences observed between the annual average gross beta air concentrations measured at the Hanford Site perimeter and those measured at distant community locations. Quarterly composite samples were analyzed for numerous specific gamma-emitting radionuclides; however, no radionuclides of Hanford origin were detected.
Annual average tritium activities for 1998 at the Hanford Site perimeter were not significantly different than annual average activities at the distant community locations. As a result of tritium studies in selected 300 Area facilities, 300 Area annual average activities in air were elevated when compared to other onsite locations. However, this effect did not increase annual average levels at site perimeter locations.
Iodine-129 activities were statistically elevated at the Hanford Site perimeter compared to the distant locations, indicating a measurable Hanford source; however, the average activity at the site perimeter was only 0.000001% of the DOE derived concentration guide of 70 pCi/m3. The DOE derived concentration guide is the air concentration that would result in a radiation dose equal to the DOE public dose limit (100 mrem/yr).
The annual average strontium-90 activities at the Hanford Site perimeter were not significantly higher than the annual average levels at the distant community locations. The maximum level was 0.004% of the DOE derived concentration guide of 9 pCi/m3.
Plutonium-239,240 annual average activities at the Hanford Site perimeter were slightly lower than the annual average activities at the distant community locations. The maximum onsite plutonium-239,240 level was 0.025% of the DOE derived concentration guide of 0.02 pCi/m3.
Uranium isotopic activities (uranium-234, -235, and -238) were similar at onsite, perimeter, and distant locations in 1998. The annual average uranium activity at the site perimeter was 0.03% of the 0.1 pCi/m3 DOE derived concentration guide.
No air samples were collected in 1998 to test for chemical contaminants.
Surface-Water and Sediment Surveillance. The Columbia River was one of the primary environmental exposure pathways to the public during 1998 as a result of past operations at the Hanford Site. Radiological and chemical contaminants entered the river along the Hanford Reach primarily through seepage of contaminated groundwater. Water samples were collected from the river at various locations throughout the year to determine compliance with applicable standards.
Although radionuclides associated with Hanford operations continued to be identified routinely in Columbia River water during the year, activities remained extremely low at all locations and were well below standards. The activities of tritium, iodine-129, and uranium were significantly higher (5% significance level) at the Richland Pumphouse (downstream from the site) than at Priest Rapids Dam (upstream from the site), indicating contribution along the Hanford Reach. Transect sampling (multiple samples collected across the river) in 1998 revealed elevated tritium activities along the Benton County shoreline near the 100-N Area, Old Hanford Townsite, 300 Area, and Richland Pumphouse. Total uranium activities were elevated along the Franklin County shoreline near the 300 Area and the Richland Pumphouse and likely resulted from groundwater seepage and water from irrigation return canals on the east of the river that contained naturally occurring uranium.
Several metals and anions were detected in transect samples collected upstream and downstream of the site. Nitrate concentrations were slightly elevated along the Benton County shoreline at the Old Hanford Townsite. Nitrate, sulfate, and chloride were slightly elevated along the Franklin County shoreline of the 300 Area and Richland Pumphouse transects and likely resulted from groundwater seepage associated with extensive irrigation north and east of the Columbia River. With the exception of nitrate, sulfate, and chloride, no consistent differences were found between average quarterly metal and anion contaminant concentrations in the Vernita Bridge and Richland Pumphouse transect samples. All metal and anion concentrations in Columbia River water collected in 1998 were less than the Washington State ambient surface-water quality criteria levels for both acute and chronic toxicity. Arsenic concentrations exceeded EPA standards; however, similar concentrations were found at Vernita Bridge (background location) and Richland Pumphouse.
In 1998, samples of Columbia River surface sediments were collected from permanently flooded monitoring sites above McNary Dam (downstream of the site) and Priest Rapids Dam (upstream of the site) and from two periodically inundated riverbank springs along the Hanford Reach. In addition, sediment samples were collected behind Ice Harbor Dam on the Snake River. Strontium-90 was the only radionuclide to exhibit consistently higher median activities at McNary Dam compared to the other locations. No other radionuclides measured in sediments in 1998 exhibited appreciable differences in activities between locations. The activities of radionuclides in sediment collected from riverbank springs were similar at both locations and were comparable to activities observed in 1998 river sediments. Detectable amounts of most metals were found in all river sediment samples. The highest maximum and median concentrations of chromium were found in riverbank springs sediment. River sediment was also analyzed for simultaneously extracted metals and acid volatile sulfide (SEM/AVS). The SEM/AVS ratios are typically a better indicator of sediment toxicity than traditional total metals concentrations. When the amount of sulfide exceeds the amount of the metals (SEM/AVS ratio is below 1), the metal concentration in the sediment porewater will be low because of the limited solubility of the metal sulfides. For 1998, the SEM/AVS molar ratios were close to one for Priest Rapids Dam and Hanford Reach sediments, with zinc as the dominant metal. The molar ratios for sediment from McNary Dam were above one, indicating a potential for some metals to be present in the sediment porewater, with zinc as the primary metal present. Ice Harbor Dam had similar concentrations of acid volatile sulfide as McNary Dam, but zinc concentrations were lower.
Water samples were collected from eight Columbia River shoreline spring areas in 1998. All radiological contaminant activities measured in riverbank springs water in 1998 were less than DOE derived concentration guides. However, the spring at the 100-N Area that has historically exceeded the DOE derived concentration guide for strontium-90 was not flowing during the 1998 sample collection visit. An alternate spring was sampled at the 100-N Area in 1998, but the strontium-90 sample was lost during processing at the analytical laboratory. Tritium activities at the Old Hanford Townsite and 100-N riverbank springs exceeded the applicable Washington State ambient surface-water quality criteria and were close to the state criteria for springs at the 100-B and 100-K Areas. There are currently no ambient surface-water quality criteria levels directly applicable to uranium; however, total uranium exceeded the site-specific proposed EPA drinking water standard in the 300 Area riverbank spring. All other radionuclides were below the Washington State ambient surface-water quality criteria levels.
Nonradiological contaminants measured in riverbank springs located on the Hanford shoreline in 1998 were below Washington State ambient surface-water acute toxicity levels, except for chromium at the 100-B, 100-D, 100-K, and 100-H Area riverbank springs. It should be noted that riverbank spring sampling protocols do not lend themselves to a direct comparison of most metal concentrations measured in riverbank springs to ambient surface-water acute and chronic toxicity levels. The standards are used instead as points of reference. Arsenic concentrations in riverbank springs water were well below the applicable ambient surface water chronic toxicity levels, but concentrations in all samples exceeded the Federal limit. Nitrate concentrations at all locations were below the EPA drinking water standard.
Water was collected from two onsite ponds located near operational areas in 1998. Although the ponds were not accessible to the public and did not constitute a direct offsite environmental impact during the year, they were accessible to migratory waterfowl and other animals. As a result, a potential biological pathway existed for the removal and dispersal of onsite pond contaminants. With the exception of uranium-234 and uranium-238 in water samples from West Lake, radionuclide activities in the onsite pond water were below DOE derived concentration guides. The median gross alpha, gross beta, and total uranium activities in West Lake exceeded the applicable ambient surface-water quality criteria levels. Activities of most radionuclides in water collected from both ponds during 1998 were similar to those observed during past years.
Irrigation water from the Riverview canal near Pasco was sampled three times in 1998 to determine radionuclide activities. Radionuclide activities in offsite irrigation water were below the DOE derived concentration guides and ambient surface-water quality criteria levels and were similar to those observed in Columbia River water.
Drinking Water Surveillance. Surveillance of Hanford Site drinking water was conducted to verify the quality of water supplied by site drinking water systems and to comply with regulatory requirements. Radiological monitoring was performed by the Pacific Northwest National Laboratory and DE&S Hanford, Inc.; nonradiological monitoring was conducted by DynCorp Tri-Cities Services, Inc. Radiological results are discussed in this report; nonradiological results are reported directly to the Washington State Department of Health.
During 1998, radionuclide activities in Hanford Site drinking water were similar to those observed in recent years and were in compliance with Washington State Department of Health and EPA drinking water standards.
Food and Farm Product Surveillance. The Hanford Site is situated in a large agricultural area that produces a wide variety of food products and alfalfa. In 1998, milk, vegetables, fruit, and wine were collected from areas around the site and were analyzed for cobalt-60, strontium-90, iodine-129, cesium.137, and tritium.
Most farm products sampled did not contain measurable levels of cobalt-60 or cesium-137. Iodine-129 was measured in milk at levels that appeared to be slightly elevated in downwind locations. Activities of iodine-129 in milk collected at downwind locations have decreased in the past 5 years, approaching the levels observed in milk collected at the upwind location. Strontium-90 was present in milk in equivalent levels at upwind and downwind locations. Tritium was also measured in milk samples and observed activities were believed to be influenced by the source of water used by the dairies. Tritium activities in wine were low and the Yakima Valley wines were lower than the Columbia Basin wines. Measurable levels of man-made radioactivity were not detected in vegetable and fruit samples collected in 1998.
Fish and Wildlife Surveillance. Carp and large-scale suckers were collected from the Columbia River in 1998. Radionuclide levels in carp collected from the Hanford Reach in 1998 were similar to the levels observed in carp and suckers from the reference background site located nearly 80 km (50 mi) upstream from the Hanford Site.
Wildlife sampled and analyzed in 1998 for radioactive constituents included elk, deer, and pheasants. Radionuclide levels in Hanford-resident wildlife were similar to levels in wildlife collected at reference background locations. The highest strontium-90 levels in deer bone samples from Hanford were collected near the closed reactors. Until recently, elk have not inhabited areas on the Hanford Site where the potential for uptake of radionuclides exists. Radionuclide levels found in four road-killed elk in 1998 did not suggest exposure to the Hanford-derived sources.
Soil and Vegetation Surveillance. Soil and vegetation samples were collected on and off the Hanford Site for the first time since 1994 as routine samples. Activities of strontium-90, cesium-137, and plutonium-239,240 in soil were similar to levels last observed from 1992 through 1994. Activities of cesium-137, uranium-238, plutonium-238, and plutonium-239,240 were below detection limits in vegetation samples collected in 1998. Strontium-90 was found in plant samples at levels comparable to values detected in 1992 to 1994 and does not indicate a positive or negative trend. Special leaf and fruit samples were also collected from trees grown near 100-F Area and the Old Hanford Townsite. These samples were analyzed for radiological materials and trace metals. Concentrations of 13 trace metals were within expected background concentrations based on published data. Strontium-90 and cesium-137 activities were similar to those observed in previous sampling, however, tritium activities were lower than levels observed in tree sampling conducted in 1997.
External Radiation Surveillance. During 1998, thermoluminescent dosimeters were used to measure radiological dose rates at both onsite and offsite locations. Radionuclides contributing to the measured dose rates were of either natural or anthropogenic (man-made) origin. The dose rates did not change significantly from the dose rates measured in the previous 5 yr. The 1998 annual average background dose rate, measured in communities considered distant from the Hanford Site, was 70 ± 2 mrem per year. In 1997, the average background dose rate was 67 ± 1 mrem per year and in 1996, the average background dose rate was 71 ±1 mrem per year. The 1998 annual average perimeter dose rate was 88 ± 7 mrem per year. In 1997, the perimeter annual average was 89 ± 10 mrem per year and in 1996, the annual average perimeter dose rate was 88 ± 10. All onsite thermoluminescent dosimeters averaged 85 ± 9 mrem per year in 1998. This compares favorably to the 85 ± 5 mrem per year reported for 1997 and the 86 ± 5 mrem per year measured in 1996. Columbia River shoreline dosimeters in 1998 averaged 91 ± 17 mrem per year, and in 1996 and 1997, the shoreline annual averages were 89 ± 7 and 90 ± 6 mrem per year, respectively. The 1998 annual average dose rate along the 100-N Area shoreline was 127 ± 21 mrem per year, while in 1997, the annual average was 121 ± 22 mrem per year. The 100-N Area shoreline dose rate (127 ± 20 mrem per year) is approximately 50% greater that the typical shoreline dose rate (86 ± 9 mrem per year).
Monitoring of radiological and chemical constituents in groundwater at the Hanford Site was performed to characterize physical and chemical trends in the flow system, to establish groundwater quality baselines, to assess groundwater remediation, and to identify new or existing groundwater problems. Groundwater monitoring was also performed to verify compliance with applicable environmental laws and regulations and to fulfill commitments made in official DOE documents. Samples were collected from over 600 wells to determine the distribution of radiological and chemical constituents in Hanford Site groundwater. In addition, hydrogeologic characterization and modeling of the groundwater flow system were used to assess the monitoring network and to evaluate potential impacts of groundwater contaminants.
Vadose zone monitoring was conducted to characterize radioactive and hazardous waste in the soil column from past intentional liquid waste disposals, accidental spills, and leachate from solid waste burial grounds. Subsurface source characterization and vadose zone monitoring, using spectral gamma logging and soil-gas monitoring, were conducted during 1997 in the vicinity of single-shell underground waste storage tanks and selected liquid waste disposal sites.
Groundwater Protection and Monitoring. The Hanford Groundwater Monitoring Project was responsible for groundwater surveillance and monitoring activities at the Hanford Site. This project incorporates sitewide groundwater monitoring mandated by DOE orders with near-field groundwater monitoring conducted to ensure that operations in and around specific waste disposal facilities comply with applicable regulations. Groundwater monitoring was required by the Resource Conservation and Recovery Act at 25 waste treatment, storage, and disposal units. Monitoring status and results for each of these units are summarized in this report.
To assess the quality of groundwater, measured sample concentrations were compared with the EPA drinking water standards and the DOE derived concentration guides. Groundwater is used for drinking at three locations on the Hanford Site. In addition, water supply wells for the city of Richland are located near the southern boundary of the Hanford Site. Radiological constituents detected at levels greater than their respective EPA drinking water standards in one or more onsite wells included tritium, iodine-129, technetium-99, uranium, strontium-90, cesium-137, carbon-14, gross alpha, and gross beta. Tritium, uranium, and strontium-90 were detected at levels greater than their respective DOE derived concentration guides.
Extensive tritium plumes extend from the 200-East and 200-West Areas into the 600 Area. The plume from the 200-East Area extends east and southeast, discharging to the Columbia River. This plume has impacted tritium activities in the 300 Area at levels of more than one-half the EPA drinking water standard. The spread of this plume farther south than the 300 Area is restricted by the groundwater flow away from the Yakima River, recharge from agricultural irrigation, and the recharge basins associated with the north Richland well field. Groundwater with tritium at levels above the EPA drinking water standard also discharges to the Columbia River at the 100-N Area. A small but high level tritium plume near the 100-K East Reactor also may discharge to the river. Tritium levels greater than the EPA drinking water standard were also found in the 100-B,C, 100-D, 100-F, and 400 Areas. Tritium occurred at levels above the DOE derived concentration guide in the 100-K and 200 Areas.
Iodine-129 was detected at levels greater than the EPA drinking water standard in the 200-East Area and in an extensive part of the 600 Area (to the east and southeast of the 200-East Area). The iodine-129 contamination extends as far east as the Columbia River but at levels less than the EPA drinking water standard. The iodine-129 and tritium plumes share common sources. Iodine-129 at levels greater than the EPA drinking water standard also extends into the 600 Area to the northwest of the 200-East Area, into the 600 Area in the southern part of the 200-West Area, and to the northeast in the north-central part of the 200-West Area.
Technetium-99 activities greater than the EPA drinking water standard were found in the northwestern part of the 200-East Area and adjacent 600 Area. Technetium-99 was also detected at levels greater than the EPA drinking water standard in the 200-West Area and adjacent 600 Area. In the upper basalt-confined aquifer, technetium-99 activities were found above the EPA drinking water standard in one well in the northern part of the 200-East Area. Greater than 338 million L (89 million gal) of groundwater have been treated and greater than 53.9 g (1.9 oz) of technetium-99 have been removed from groundwater since a pump-and-treat system began operating in the 200-West Area in 1994.
Uranium was detected at levels greater than the EPA drinking water standard in groundwater in the 100-F, 100-H, 200, 300, and 600 Areas. Wells near U Plant in the 200 West Area showed activities greater the DOE derived concentration guide. A pump-and-treat system has removed 80.4 kg (177 lb) of uranium from groundwater in the 200-West Area since 1994. Groundwater with uranium levels greater than the EPA drinking water standard is discharging to the Columbia River from the 300 Area.
The strontium-90 plume in the 100-N Area, which contains activities greater than the EPA drinking water standard and the DOE derived concentration guide, discharges to the Columbia River. Localized areas in the 100-K and 200-East Areas and near the former Gable Mountain Pond in the 600 Area also contain strontium-90 at levels greater than the DOE derived concentration guide. Strontium-90 was detected at levels greater than the EPA drinking water standard in the 100, 200, and 600 Areas. Strontium-90 continues to be remediated in the 100 N Area by a pump-and-treat system to reduce the amount of strontium-90 entering the Columbia River.
Cesium-137 was detected above the EPA drinking water standard in a localized area associated with a former injection well in the 200-East Area. Plutonium was also detected in this localized area, but at levels less than the 100-mrem/yr dose equivalent guideline.
Cobalt-60 was detected in the 200-East Area and adjacent 600 Area but at levels less than the EPA drinking water standard.
Carbon-14 activity exceeded the EPA drinking water standard near each of the reactors in the 100 K Area.
Several nonradioactive chemicals regulated by EPA and Washington State were also present in Hanford Site groundwater. These were nitrate, chromium, carbon tetrachloride, chloroform, trichloroethylene, tetrachloroethylene, cis-1,2-dichloroethylene, cyanide, and fluoride. Of these chemicals, nitrate, chromium, and carbon tetrachloride are the most widely distributed constituents in Hanford Site groundwater.
Nitrate concentrations exceeded the EPA drinking water standard in all areas, except the 100-B,C and 400 Areas. The nitrate plumes in the 100 Areas discharge to the Columbia River. A nitrate plume emanating from the 200-East Area extends east and southeast in the same area as the tritium plume. Nitrate from sources in the northwestern part of the 200-East Area is present in the adjacent 600 Area at levels greater than the EPA drinking water standard. Nitrate levels greater than the EPA drinking water standard occur in two areas of the 200-West Area and adjoining 600 Area. A pump-and-treat system in the 200-West Area has removed 7,910 kg (17,442 lb) of nitrate from groundwater.
Chromium was detected above the EPA drinking water standard in the 100-D, 100-H, and 100-K Areas and in localized sites in the 100 B/C, 100-K, 200-East, 200-West, and 600 Areas. Since pump-and-treat systems began operating in the 100-D, 100-H, and 100-K Areas in 1997, 98 kg (209 lb) of chromium has been removed from groundwater.
An extensive plume of carbon tetrachloride at levels greater than the EPA drinking water standard occurs in groundwater in the 200-West Area and adjoining 600 Area. As of September 1998, greater than 953 million L (251 million gal) of groundwater have been treated at two pump-and-treat systems operating in the 200 West Area, resulting in the removal of approximately 2,113 kg (4,667 lb) of carbon tetrachloride.
Levels of trichloroethylene and chloroform were above the EPA drinking water standard in the 200 West Area. Trichloroethylene was found at levels greater than the EPA drinking water standard in the 100-F Area and the nearby 600 Area. Trichloroethylene was also detected at levels above the EPA drinking water standard in the 100-K and 300 Areas and near the former Horn Rapids Landfill in the southern part of the Hanford Site.
A new plume of tetrachloroethylene with levels above the EPA drinking water standard was detected in the 300 Area. However, levels fell below the standard by the end of 1998.
Cis-1,2-dichloroethylene concentrations were above the EPA drinking water standard in one well in the 300 Area. Cyanide was detected in groundwater in the 200-East Area but at levels below the EPA drinking water standard. Fluoride was detected at a level above the EPA drinking water standard in one well in the 200-West Area.
Tank Farms Vadose Zone Baseline Characterization Project. The multiyear vadose zone baseline characterization project at the single-shell tank farms continued in 1998. This project involves spectral gamma-ray geophysical logging of approximately 800 existing boreholes surrounding the tank farms, creating a database of information and providing interpretations and three-dimensional visualizations (computer-generated illustrations) of the subsurface contamination. The geophysical logging method is used to determine the activity of gamma-emitting radionuclides in the subsurface. These data are then used to outline the regions of major subsurface contamination and to identify where to focus the effort of a more comprehensive vadose zone characterization program.
During 1998, the baseline logging was completed. Spectral gamma data were acquired in 79 boreholes in T Farm and B Farm. Reports were completed for 27 tanks and 3 tank farms. Report preparation, repeat logging, shape factor analysis, and high-rate logging will continue through 1999.
Vadose Zone Monitoring at Waste Disposal Facilities. Radioactive and hazardous waste in the soil column from past intentional liquid waste disposals, accidental spills, and leachate from solid waste burial grounds at the Hanford site are potential sources of current and future groundwater contamination. Subsurface source characterization and vadose zone monitoring, using spectral gamma logging and soil-gas monitoring were conducted during 1998. Also in 1998, physical, chemical and hydraulic properties were measured from samples obtained from characterization boreholes at the Immobilized Low-Activity Waste site, which is the site for privatization activities associated with retrieval and processing tank waste located in the 200-East Area, to support performance assessment modeling; at the 216-B-2-2 ditch, in the 200-East Area, to support 200 Areas soils remediation; and at the extension of borehole 41-09-39 in the 200-West Area SX single-shell tank farm to support tank remediation/closure.
The objectives of vadose zone monitoring are to document contaminant location and to determine moisture and radionuclide movement in the soil column. Spectral gamma logging is an in situ measurement of subsurface gamma-emitting radionuclides obtained through cased monitoring wells that are completed in the vadose zone or extended into the saturated zone. By periodically recording gamma-ray activity at various depths, changes over time can be documented.
During 1998, in situ spectral gamma logging was performed in 21 boreholes at the 216-Z-1A, -9, and -12 liquid waste-disposal facilities associated with the Plutonium Finishing Plant located in the 200 West Area. Cesium-137, protactinium-233, plutonium-239, and americium-241 were identified in the logs. Comparisons of log data collected in 1998 with data from past logging events suggest that some changes have occurred in radionuclide activity around two boreholes in the 216-Z-1A tile field and around one borehole in the 216-Z-12 crib.
In one borehole at the 216-Z-1A tile field, there was an apparent decrease in protactinium-233 activity to ~1/3 of 1991 values between 13.4 and 15 m (43.9 to 49.2 ft), with no apparent change above or below that zone. This suggests a lateral, not a vertical, change in protactinium-233 activity. Also, between 13 and 16 m (42.6 and 52.5 ft), cesium-137 activity decreased by a factor of ~3, compared to the 1991 log. In another borehole at the 216-Z-1A tile field, a 51% increase in protactinium-233 activity was found between 6 and 16 m (19.7 and 52.5 ft) and a 22% increase between 28 and 29 m (91.9 and 95.1 ft) when compared to previous logs. Only one borehole at the 216-Z-12 crib suggested that there were changes in subsurface distribution of radionuclides since the last logging in 1993. Protactinium-233 showed an apparent 16% increase, and plutonium-239 showed an apparent 123% increase over the 4.6 to 5.5 m (15 to 18 ft) depth interval. The general conclusion is that transuranics were relatively mobile at the time of discharge to the 216.Z.1A tile field but have been fairly stable since.
The Tank Waste Remediation Systems program is focusing on resolving tank safety issues, planning for waste retrieval, developing waste-pretreatment and -treatment facilities, and evaluating waste-storage and -disposal needs for single-shell tank wastes. Vitrification and onsite disposal of low-activity waste from single-shell tanks are included in the strategy described in the Hanford Site Federal Facility Agreement and Consent Order (commonly known as the Tri-Party Agreement; Washington State Department of Ecology et al. 1989). The current plan is to dispose of immobilized low-activity tank waste in new facilities in the south-central part of the 200 East Area and in four existing vaults (unused, reinforced concrete structures remaining at the former Grout Treatment Facility) along the eastern side of the 200 East Area. In 1998, three boreholes were drilled at the southwestern corner of the Immobilized Low-Activity Waste disposal site in support of the performance assessment activities for the disposal options.
Geologic logging of the deepest boreholes at the Hanford Site showed for the first time the existence of three paleosols (layers) in a single borehole. The paleosols, which represent significant time intervals when soil development took place in the geologic past, have the potential to retard downward movement of moisture through the vadose zone at their location. The detailed stratigraphy from the borehole sets a good background for the subsequent chemical transport, physical properties, and estimation of recharge tests.
Twenty samples from the borehole were analyzed for physical and hydraulic properties. The variability among the hydrologic and physical data was within the range previously reported for 200 Areas sediments. This increases confidence that existing data sets are representative of the range of physical and hydrologic properties present in the uncontaminated portions of the 200 Areas and may be representative of many of the contaminated portions of the 200 Areas. The data represent the most complete set of physical properties and hydrologic properties measured on undisturbed core samples at the Hanford Site. The data will be input to performance assessment of the Immobilized Low-Activity Waste disposal site.
Borehole 41-09-39 was initially drilled in 1996 at the SX single-shell tank farm, in the 200 West Area, in response to the determination that cesium-137 might reside in the soil column at depths greater than previously thought. Geophysical logging confirmed that cesium-137 contamination was present at the total depth of the borehole. Concern was raised that if relatively immobile cesium-137 was present at that depth, then more-mobile, long-lived, tank-waste constituents might be at or near the water table. In response to a recommendation of an expert panel brought together to address these early findings, borehole 41-09-39 was extended to groundwater in 1998 and samples were collected for laboratory analysis of tank-waste components.
Samples from seven selected locations within the borehole were analyzed for radionuclides, chemical constituents, cation-exchange capacity, and particle-size distribution. Detailed geochemical analyses of the seven samples from this borehole showed that tank-waste constituents are predominantly held within or above a prominent geologic layer known as the Plio-Pleistocene unit. Analyses showed that cesium-137 activity in the soils was highest in the Plio-Pleistocene sediments at 40 m (131 ft) depth. Activity dropped off rapidly and was at or below detection levels from 48.8 m (160 ft) to the water table at 64.3 m (210 ft).
Distribution of technetium-99, the most mobile of the long-lived radionuclides found in tank wastes, was sporadic, with most occurrences above the Plio-Pleistocene unit. A single, deep occurrence was noted at the depth postulated to be the highest level reached by groundwater during operation of the 216.U-10 pond (now decommissioned) located west of the SX single-shell tank farm. It is possible that technetium-99 was found in this sediment sample due to horizontal migration from disposal facilities outside the tank farm boundaries.
Groundwater samples were collected from 3, 0.6, and 0.02 m (10, 2, and 0.06 ft) below the water table. Analyses of these samples showed technetium-99 and tritium activities indicative of an upgradient sources. These analyses indicate that groundwater contamination at this specific location is due to non-tank farm sources. More sampling of vadose-zone sediments under the SX tank farm at additional locations is needed to determine whether the contaminants in downgradient monitoring wells may have originated from the single-shell tanks or from non-tank-related liquid discharge facilities nearby.
A characterization borehole was drilled through the 216-B-2-2 ditch, in the 200 East Area, to groundwater during late 1997 and early 1998. This ditch was selected for characterization because it is considered representative of the 200-CW-1 Gable Mountain Pond/B Pond and Ditches Cooling Water Group (formerly the 200-BP-11 Operable Unit).
Chemical and radiochemical analyses were conducted on samples from the borehole. With one exception, the results showed that the distribution of chemical constituents and man-made radionuclides underlying the 216-B-2-2 ditch is consistent with the conceptual model developed for the 200-CW-1 group. The conceptual model for this group is that the highest activity of the primary contaminants of concern will be directly underlying the headend of the ditch. Furthermore, according to the conceptual model, most of the contaminants were expected to be within the uppermost gravel unit, which at this site extends to a depth of 9.1 m (29.8 ft). The only exception was one nontarget volatile organic (total xylenes) detected at 8 µg/kg in the 45.7- to 46.5-m (150- to 152.5-ft) interval.
Soil-vapor extraction is being used to remove the carbon tetrachloride from the vadose zone as part of the 200-West Area expedited response action. To track the effectiveness of the remediation effort, measurements of soil-vapor concentrations of chlorinated hydrocarbons were made at the inlet to the soil-vapor-extraction system, at individual operating extraction wells, and at individual standby wells during 1998.
During a total of 178 d of soil-vapor extraction in 1998, 777 kg (1,700 lb) of carbon tetrachloride were removed from the vadose zone. As of September 1998, ~75,000 kg (165,000 lb) of carbon tetrachloride had been removed from the subsurface since extraction operations started in 1992. Since initiation, the extraction systems are estimated to have removed 7% of the residual mass at the 216-Z-1A/-18 well field and 22% of the mass at the 216-Z-9 well field.
During October 1997 through March 1998, soil-vapor concentrations were monitored near the groundwater and near the ground surface to assess whether a shutdown of the soil-vapor-extraction system allowed carbon tetrachloride to migrate out of the vadose zone. The results showed that carbon tetrachloride concentrations did not increase significantly at either the shallow probes monitored in 1998 or the deeper probes near the groundwater. This indicates that temporarily suspending operation of the soil-vapor-extraction system for 6 to 9 mo appears to cause minimal detectable vertical transport of carbon tetrachloride through the soil surface to the atmosphere and to have had no negative impact on groundwater quality.
Carbon tetrachloride rebound concentrations indicate that in many areas much of the readily accessible mass has been removed during soil-vapor-extraction operations and that the supply of additional carbon tetrachloride is limited by desorption and/or diffusion from subsurface contaminant sources. Under these conditions, the removal rate of the additional carbon tetrachloride using soil-vapor extraction is controlled by the desorption and diffusion rates of the contaminant.
In 1998, potential radiological doses to the public, resulting from exposure to Hanford Site liquid and gaseous effluents, were evaluated to determine compliance with pertinent regulations and limits. These doses were calculated using reported effluent releases and environmental surveillance data using version 1.485 of the GENII computer code and Hanford-specific parameters. The potential dose to the maximally exposed individual in 1998 from site operations was 0.02 mrem (0.2 µSv) compared to 0.01 mrem calculated for 1997. The radiological dose to the population within 80 km (50 miles) of the site, estimated to be 380,000 persons, from 1998 site operations was 0.2 person-rem (0.002 person-Sv), which remained unchanged from the population doses calculated in 1997 and 1996. The average per-capita dose from 1998 site operations was 0.0005 mrem (0.005 µSv).
The national average dose from background sources, according to the National Council on Radiation Protection, is approximately 300 mrem/yr (3 mSv/yr), and the current DOE radiological dose limit for a member of the public is 100 mrem/yr (1 mSv/yr). Therefore, the average individual potentially received 0.0005% of the DOE limit and 0.0002% of the national average background. Special exposure scenarios not included in the dose estimate above included the hunting and consumption of game animals residing on the Hanford Site and exposure to radiation at a publicly accessible location with the maximum exposure rate. Doses from these scenarios would have been small compared to the DOE dose limit. Radiological dose through the air pathway was calculated to be 0.13% of the EPA limit of 10 mrem/yr (0.1 mSv/yr).
Meteorological measurements are taken to support Hanford Site emergency preparedness, site operations, and atmospheric dispersion calculations. Hanford Site meteorologists provide weather forecasting, and maintenance and distribution of climatological data.
The Hanford Meteorology Station is located on the 200 Areas plateau, where the prevailing wind direction is from the northwest during all months. The secondary wind direction is from the southwest. The average speed for 1998 was 12.7 km/h (7.9 mi/h), which was 0.3 km/h (0.2 mi/h) above normal; the peak gust for the year was 90 km/h (56 mi/h).
Precipitation for 1998 totaled 16.4 cm (6.5 in.), 103% of normal, with 18.3 cm (7.2 in.) of snow recorded.
1998 was much warmer than normal, tying 1992 as the warmest year on record. Temperatures for 1998 ranged from 44.4°C (112°F) in July to -18.3°C (-1°F) in December. The highest July temperature ever recorded was 44.4°C (112°F) on July 27, 1998. The first week in May, three daily temperature records were broken or tied. November 1998 was the third warmest on record. For the year 1998, there were 73 d with maximum temperature >=90°F, the third highest on record. For the 12-mo period, 11 mo were warmer than normal and 1 was cooler than normal. The summer (June, July, and August) and autumn (September, October, and November) of 1998 were the fourth warmest on record.
Management of archaeological, historical, and traditional cultural resources at the Hanford Site is provided in compliance with the National Historic Preservation Act, Native American Graves Protection and Repatriation Act, Archaeological Resources Protection Act, and American Indian Religious Freedom Act. During 1998, 150 proposed projects were reviewed to consider their potential effect on significant cultural resources. Other activities included the continuation of a multiyear monitoring study of cutbank erosion and associated impacts to National Register archaeological sites at Locke Island, a large channel island located in the northern extent of the Hanford Reach of the Columbia River. Mitigation of historic buildings and structures continued in 1998 as required by the programmatic agreement for the built environment and the historic district treatment plan.
Public involvement activities are important components of a cultural resources management program. To accomplish this goal, DOE developed mechanisms that allow the public access to cultural resources information and the ability to comment and make recommendations concerning the management of cultural resources on the Hanford Site. In 1998, these mechanisms were woven into a draft involvement plan that includes input provided by the public and Hanford Site staff over the past several years. Native American involvement included the completion of several field surveys, construction monitoring, and monthly cultural issues meetings.
This program was initiated in 1990 to increase the public's involvement in and awareness of Hanford's surveillance program. Nine citizen-operated radiological surveillance stations were operating in 1998.
The noxious weed control program on the Hanford Site was developed in response to federal, state, and local laws requiring eradication or control of noxious weeds. A noxious weed is defined as any plant that, when established, is highly destructive, competitive, or difficult to control by cultural or chemical practices. Typically, noxious weeds are non-native species that invade and displace native species, reduce habitat for fish and wildlife, and contribute to the extinction of sensitive species. Nine plants are on the high-priority list for control at the Hanford Site. These include yellow starthistle, rush skeletonweed, babysbreath, dalmation toadflax, spotted knapweed, diffuse knapweed, Russian knapweed, saltcedar, and purple loosestrife. All these plants were monitored in 1998, but control measures focused on the more invasive species.
Comprehensive quality assurance programs, which include various quality control practices and methods to verify data, are maintained to ensure data quality. The programs are implemented through quality assurance plans designed to meet requirements of the American National Standards Institute/American Society of Mechanical Engineers and DOE Orders. Quality assurance plans are maintained for all activities, and auditors verify conformance. Quality control methods include, but are not limited to, replicate sampling and analysis, analysis of field blanks and blind reference standards, participation in interlaboratory crosscheck studies, and splitting samples with other laboratories. Sample collection and laboratory analyses are conducted using documented and approved procedures. When sample results are received, they are screened for anomalous values by comparing them to recent results and historical data. Analytical laboratory performance on the submitted double blind samples, the EPA Laboratory Intercomparison Studies Program, and the national DOE Quality Assessment Program indicated that laboratory performance was adequate overall, was excellent in some areas, and needed improvement in others.
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URL: http://www.hanford.gov/docs/annualrp98/summary.htm
Document Number:
PNL-12088
Document Date: September 1999
Posted: September 1999