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 and 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.
The DOE has ended the production of nuclear materials at the Hanford Site for weapons. The current mission being implemented by the 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 the 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 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 is building the Laser Interferometer Gravitational-Wave Observatory facility near Rattlesnake Mountain. R. H. Smith Distributing operates vehicle fueling stations in the 1100 and 200 Areas. Washington State University at Tri-Cities operates three laboratories in the 300 Area. Livingston Rebuild Center, Inc. leases the 1171 Building 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). 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 and with treatment, storage, and disposal unit regulation and corrective action provisions of the Resource Conservation and Recovery Act. From 1989 through 1997, a total of 562 enforceable Tri-Party Agreement milestones and 237 unenforceable target dates were completed on or ahead of schedule. Fifty-seven milestones scheduled for 1997 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 1997, 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 Areas in 1997.
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 1997 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 1998. 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. No such reporting thresholds were exceeded in 1996, so no report was required in 1997. During 1997, 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 the EPA to implement its dangerous waste program in lieu of the EPA for Washington State, 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. The EPA has 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 1998.
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 County Clean Air Authority) regulations pertain to detrimental effects, fugitive dust, 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 1997 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 1997, all Hanford Site water systems were in compliance with requirements and agreements.
The application of this Act's requirements to the Hanford Site essentially 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.
The 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 1997, 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. Four of these (bald eagle, peregrine falcon, Aleutian Canada goose, and steelhead trout) are listed by the U.S. Fish and Wildlife Service as endangered or threatened. Others are listed by the Washington State Department of Fish and Wildlife as endangered, threatened, or sensitive. Hanford Site activities complied with this Act in 1997.
Cultural resources on the Hanford Site are subject to the provisions of these Acts. In 1997, 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 1997 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 were two emergency occurrence reports filed in 1997 and early 1998. No environmentally significant unusual occurrence reports were filed in 1997. There were several off-normal environmental release-related occurrence reports filed during 1997.
Radioactive, hazardous, and mixed wastes are generated at approximately 200 facilities on the Hanford Site. These wastes are handled and prepared for safe storage on the site or are shipped off the site for treatment and disposal. In addition to newly generated waste, significant quantities of waste remain from over 50 years of nuclear material production. This waste from past operations at Hanford 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 Hanford is focused on protecting the public from exposure to this waste.
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 hazardous constituents are continually monitored at the Hanford Site. Facility operators monitor effluents mainly through analyzing samples collected near points of release into the environment. Effluent monitoring data are evaluated to determine their degree of compliance with applicable federal, state, and local regulations and permits.
Measuring devices are used to quantify most facility effluent flows, with a smaller number of flows calculated using process information. Liquid and gaseous effluents with a potential to contain radioactivity at prescribed threshold levels are monitored for gross alpha and gross beta activity and, as warranted, specific gamma-emitting radionuclides. Nonradioactive hazardous constituents are also monitored, as applicable.
Radioactive effluents from many onsite facilities are approaching levels practically indistinguishable from the naturally occurring radioactivity present everywhere. This decrease translates to a very small offsite radiation dose attributable to site activities. The site mission of environmental restoration rather than nuclear materials production is largely responsible for this trend. Consistent with these conditions of diminishing releases, totals of radionuclides in effluents released at the site in 1997 are not significantly different from totals in 1996.
Near-Facility Environmental Monitoring. The near-facility environmental monitoring program is designed to protect the environment adjacent to 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 and springs, surface contamination, soil and vegetation, external radiation, and investigative sampling (which can include wildlife) were sampled. Some of the parameters typically monitored are pH, radionuclide concentrations, 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 62 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 concentrations for these radionuclides were elevated near facilities compared to the concentrations measured off the site by Pacific Northwest National Laboratory.
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.
Radiological analytical results for liquid samples from surface-water disposal units in the 200 Areas 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 radiological 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 concentrations in the springs along the shoreline, the results can be compared to the concentrations measured at the facility effluent monitoring well. In 1997, the concentrations detected in samples from shoreline springs were highest in springs nearest the effluent monitoring well.
Near-Facility Radiological Surveys. In 1997, there were approximately 3,990 ha (9,859 acres) of posted outdoor contamination areas and 614 ha (1,517 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 1997.
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. Soil and vegetation sample concentrations for some radionuclides were elevated near facilities when compared to concentrations measured off the site. The concentrations show a large degree of variance; in general, samples collected on or adjacent to waste disposal facilities had significantly higher concentrations 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 1997 to evaluate environmental restoration activities at the 116-B-11 Water Retention Basin and the 116-C-1 Liquid Waste Disposal Trench. The 1997 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 1997 readings were comparable to offsite background levels.
This is the fifth 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. Three of the dosimeters have consistently shown elevated readings as a result of their proximity to radioactive waste storage areas or stored radioactive rail equipment.
A hand-held micro-rem meter (to measure low-level radiation exposure) was used to survey points along the 100-N Area shoreline springs. The radiation rates measured continued to decline in 1997, reflecting discontinued discharges to the 1301-N Liquid Waste Disposal Facility and the continuing decay of its radionuclide inventory.
The 1997 thermoluminescent dosimeter results indicate that direct radiation levels are 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 1996.
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 measured in 1997 was 110 mrem/yr, approximately 8% lower than the dose rate measured in 1996.
Two thermoluminescent dosimeter locations were established at the Environmental Restoration Disposal Facility during late 1996 to evaluate the disposal activities in progress. Readings in 1997 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 1997 was 110 mrem/yr, a decrease of 8% compared to the average measured in 1996. The average annual dose rate at the 300 Area Treated Effluent Disposal Facility in 1997 was 82 mrem/yr, a decrease of 4% compared to the average dose rate measured in 1996.
The average annual dose rate measured in the 400 Area in 1997 was 86 mrem/yr, an increase of 3% compared to the average dose rate measured in 1996.
Investigative Sampling. To confirm the absence or presence of radioactive or hazardous contaminants, investigative sampling was conducted in the operations areas near facilities such as storage and disposal sites for at least one of the following reasons:
The maximum concentrations of radioactive isotopes from samples collected during these investigations are included in this report.
Generally, the predominant radionuclides discovered during these efforts were activation products and strontium-90 in the 100 Areas, fission products in the 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 1997 included sludge, soil, vegetation, and wildlife and were collected where known or suspected radioactive contamination was present or to verify radiological conditions at project sites. In 1997, 80 samples were analyzed for radionuclides, and 27 showed some level of contamination. In addition, 115 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 and wildlife, soil and vegetation, and external radiation.
Air Surveillance. Radioactive materials in air were sampled continuously at 39 onsite locations, at the 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 site are also found worldwide from two other sources: naturally occurring radionuclides and radioactive fallout from historical nuclear activities not associated with Hanford. The potential influence of emissions from site activities on local radionuclide concentrations was evaluated by comparing differences between concentrations measured at distant locations within the region and concentrations measured at the site perimeter.
For 1997, no differences were observed between the annual average gross alpha and gross beta air concentrations measured at the 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 consistently.
Tritium concentrations for 1997 were slightly lower at the site perimeter compared to the distant station.
Iodine-129 concentrations were statistically elevated at the site perimeter compared to the distant locations, indicating a measurable Hanford source; however, the average concentration 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).
Strontium-90 was detected in 1 of the 9 onsite air samples, with the maximum concentration at 0.001% of the DOE derived concentration guide of 9 pCi/m3. Strontium-90 was not detected at any of the perimeter and distant locations.
Plutonium-239,240 concentrations were significantly elevated for air samples collected at the site perimeter compared to the distant locations, indicating a Hanford influence. The average concentration at the perimeter locations was less than 0.002% of the DOE derived concentration guide of 0.02 pCi/m3. The maximum onsite plutonium-239,240 concentration was 0.02% of the DOE derived concentration guide of 0.02 pCi/m3.
Uranium isotopic concentrations (uranium-234, uranium-235, and uranium-238) were similar on the site, at the perimeter, and at the distant locations for 1997. The annual average uranium concentration at the site perimeter was 0.03% of the 0.1-pCi/m3 DOE derived concentration guide.
No air samples were collected in 1997 to test for nonradionuclides.
Surface-Water and Sediment Surveillance. The Columbia River was one of the primary environmental exposure pathways to the public during 1997 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, concentrations remained extremely low at all locations and were well below standards. The concentrations 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 1997 revealed elevated tritium concentrations along the Benton County shoreline near the 100-N Area, Old Hanford Townsite, 300 Area, and Richland Pumphouse. Total uranium concentrations were elevated along the Franklin County shoreline near the 300 Area and the Richland Pumphouse and likely resulted from groundwater seepage and irrigation return canals east of the river.
Several metals and anions were detected in transect samples collected upstream and downstream of the site. Nitrate concentrations were elevated along the Benton County shoreline at the Old Hanford Townsite and 300 Area. Nitrate, sulfate, and chloride were elevated along the Franklin County shoreline for the 300 Area and Richland Pumphouse transects. With the exception of nitrate, sulfate, and chloride, which had slightly higher average quarterly concentrations at the Richland Pumphouse, 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 1997 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 measured for transect samples collected at Vernita Bridge (background location) and Richland Pumphouse.
In 1997, 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 along the Hanford Reach. Strontium-90 was the only radionuclide to exhibit consistently higher median concentrations at McNary Dam compared to the other location. Sediment samples were also collected from four periodically inundated Columbia River shoreline springs. The concentrations of radionuclides in sediment collected from riverbank springs were similar at all locations and were comparable to river sediment collected behind Priest Rapids Dam. Similar concentrations of most metals were found in Columbia River and riverbank springs 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. SEM/AVS ratios were below 1.0 for all metals, except for zinc that was above 1.0 for some samples.
Water samples were collected from six Columbia River shoreline spring areas in 1997. All radiological contaminant concentrations measured in riverbank springs water in 1997 were less than the DOE derived concentration guides, except for strontium-90 at the 100-N Area where one spring was nearly 10 times the standard. The tritium concentration at the Old Hanford Townsite riverbank spring exceeded the Washington State ambient surface-water quality criteria level and was close to the criteria for springs at the 100-B and 100-N 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 1997 were below Washington State ambient surface-water acute toxicity levels, except for chromium at the 100-D and 100-H Area springs. The Washington State ambient surface-water chronic toxicity levels for chromium and lead were exceeded at some locations. 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 a point of reference. Nitrate concentrations were the highest at the 100-F Area, but all locations were below the EPA drinking water standard.
Water was collected from three onsite ponds located near operational areas in 1997. Although the ponds were not accessible to the public and did not constitute a direct offsite environmental impact during 1997, 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 concentrations in the onsite pond water were below the DOE derived concentration guides. The median gross beta and uranium concentrations in West Lake exceeded the ambient surface-water quality criteria levels. Concentrations of most radionuclides in water collected from all three ponds during 1997 were similar to those observed during past years.
Irrigation water from the Riverview canal near Pasco was sampled three times in 1997 to determine radionuclide concentrations. Radionuclide concentrations 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 1997, radionuclide concentrations in 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. Milk, vegetables, fruit, alfalfa, 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 concentrations of cobalt-60 or cesium-137. Iodine-129 was measured in milk at concentrations that appeared to be slightly elevated in downwind locations. Concentrations of iodine-129 in milk collected at downwind locations have decreased in the past 5 years, approaching the concentrations observed in milk collected at the upwind location. Strontium-90 was present in milk in equivalent concentrations at upwind and downwind locations. Tritium concentrations in wine were equivalent to background levels in surface water and do not indicate any upwind or downwind influence from Hanford. Strontium-90 concentrations in alfalfa have previously been slightly elevated in samples irrigated with Columbia River water withdrawn downstream of the site. In 1997, this effect was not as apparent. Strontium-90 concentrations in alfalfa samples analyzed in 1997 are low and close to background levels. Measurable levels of man-made radioactivity were not detected in vegetables and fruit samples collected in 1997.
Fish and Wildlife Surveillance. Analyses of fish and wildlife samples in 1997 indicated that some species had accumulated radionuclides at concentrations greater than background levels. Sculpins were collected near the 100-N Area springs as part of a special study with the Washington State Department of Health. Sculpins were sampled because they have a small home range and their exposure in the 100-N Area springs is more constant than that of more mobile fish that are routinely sampled. Concentrations of strontium-90 in sculpins collected in the vicinity of the 100-N Area springs were significantly higher than in a control group of sculpins collected upstream. Sculpins are not consumed by humans, but they have value as a biomonitoring species. Concentrations of strontium-90 in Columbia River whitefish collected near the 100-N Area in 1997 were considerably lower than in sculpins. Unlike sculpins, whitefish may be consumed by people.
Geese were also collected from around the 100-N to 100-D Area and at the Old Hanford Townsite. Concentrations of cesium-137 were at the limit of detection (0.02 pCi/g) in muscle. Strontium-90 concentrations in goose bone were lower than observed in 1995 and were within or below the range of strontium-90 in background samples of other wildlife species collected over the past decade. Collectively, the concentrations of radionuclides measured in fish and geese samples indicate accumulations of small amounts of specific radionuclides that possibly originated either from historic fallout or Hanford Site activities.
Special surveillance studies were also conducted in conjunction with the Washington State Department of Health to establish trace metal concentrations in aquatic organisms from the 100-N Area springs. Metals data were collected from bass, caddis fly larvae and adults, carp, clams, sculpin, and sucker. These samples provided additional data to assess the potential distribution and possible impacts of metals in the Columbia River ecosystem.
Soil and Vegetation Surveillance. Soil and vegetation samples were collected for special surveillance activities in association with cleanup activities in the 300 Area operable units. Samples were collected around the cleanup area to the north of the 300 Area and at five locations in Franklin County across the Columbia River and east of the 300 Area. Neither soil nor vegetation samples indicated any transport of contaminated dust off the site.
Special samples were also collected from fruit trees grown on the site. Three apricot trees (leaf samples only) and a quince tree (leaves and fruit) were sampled. Two apricot trees were sampled from an abandoned orchard northeast of the 100-D Area. These samples had approximately 600 pCi/L of tritium in water distilled from leaf samples. Concentrations of strontium-90 in all tree leaf samples were within levels associated with background concentrations in vegetation samples routinely monitored in undeveloped areas of the Hanford Site. These samples were also analyzed for metals. Observed concentrations of metals fell within the range of concentrations associated with natural background levels.
Metal concentrations were also determined for reed canary grass and milfoil collected from the 100-N Area springs and an upriver control station near the Vernita Bridge. Metal concentrations were within the range of natural concentrations.
External Radiation Surveillance. Using thermoluminescent dosimeters, radiological dose rates were measured at both onsite and offsite locations during 1997. Radioactive substances contributing to the measured dose rates were of either natural or man-made origin. The dose rates did not change significantly from the dose rates measured in previous years. The 1997 annual average background dose rate measured in communities distant from the Hanford Site was 67 ± 1 mrem/yr; in 1996, the average background was 71 ± 1. The 1997 annual average perimeter dose rate was 89 ± 10 mrem/yr; in 1996, the average measured dose rate was 88 ± 10 mrem/yr. All onsite thermoluminescent dosimeters averaged 85 ± 5 mrem/yr, which compares favorably with the average of 86 ± 5 mrem/yr measured in 1996. Columbia River shoreline dosimeters had a 1997 average of 90 ± 6 mrem/yr; in 1996, the average was 89 ± 7 mrem/yr. The average dose rate along the 100-N Area shoreline (121 ± 22 mrem/yr) was approximately 50% higher than the typical shoreline dose rate (85 ± 3 mrem/yr).
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 700 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, gross alpha, and gross beta. Tritium, uranium, and strontium-90 were detected at concentrations 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 concentrations 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 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 concentration 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, and 400 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 concentrations 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 concentrations 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 100-H and 200-West Areas and adjacent 600 Area. In the upper basalt-confined aquifer, technetium-99 concentrations were found above the EPA drinking water standard in one well in the northern part of the 200-East Area. Greater than 180,900,000 L (47,800,000 gal) of groundwater have been treated and greater than 43.4 g (1.4 oz) of technetium-99 have been removed from groundwater since a pump-and-treat system began operating in the 200-West Area in 1994. Assessment studies indicate that Waste Management Areas B-BX-BY, SX, T, and TX-TY (where the tank farms are located) are sources of technetium-99 contamination in groundwater.
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 concentrations greater the DOE derived concentration guide. A pump-and-treat system has removed 56.8 kg (125 lb) of uranium from groundwater in the 200-West Area since 1994. Groundwater with uranium concentrations 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 concentrations greater than 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.
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 concentrations less than the 100-mrem/yr dose equivalent guideline.
Cobalt-60 was detected in the 200-East Area and adjacent 600 Area but at concentrations less than the EPA drinking water standard.
Several nonradioactive chemicals regulated by the EPA and Washington State were also present in Hanford Site groundwater. These were nitrate, chromium, carbon tetrachloride, chloroform, trichloroethylene, 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 removed 2,260 kg (4,938 lb) of nitrate from groundwater in 1997.
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-K, 200-East, 200-West, and 600 Areas. Pump-and-treat systems began operating in the 100-D, 100-H, and 100-K Areas in 1997 to remove chromium 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 1997, greater than 117,800,000 L (31,100,000 gal) of groundwater have been treated at two pump-and-treat systems operating in the 200-West Area, resulting in the removal of approximately 870 kg (1,918 lb) of carbon tetrachloride.
Levels of trichloroethylene and chloroform have been known to consistently occur above the EPA drinking water standard from year to year in the 200-West Area. However, the distribution of these levels for 1997 could not be defined because of sample interference from high levels of carbon tetrachloride. 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.
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 the same level as 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 1997. 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 concentration 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 1997, 211 additional boreholes, surrounding 42 tanks, were logged. Interpretations were made on a farmwide basis for four tank farms, and visualizations were prepared for the contamination at those farms.
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 are potential sources of current and future groundwater contamination. Subsurface source characterization and vadose zone monitoring, using spectral gamma-ray logging and soil-gas monitoring, were conducted during 1997. The efforts focused primarily on vadose zone soil contamination associated with past liquid disposals to cribs, trenches, drain fields, and reverse wells at Waste Management Area B-BX-BY, Plutonium Finishing Plant liquid waste disposal sites, and Nonradioactive Dangerous Waste Landfill (part of the Central Landfill). The objectives of vadose zone borehole monitoring are to document contamination location and to determine moisture and radionuclide movement in the soil column. Borehole spectral gamma-ray logging is an in situ measurement of subsurface gamma-emitting radionuclides obtained through cased monitoring wells. By periodically recording detector response at various depths, changes over time can be documented.
Sixteen wells were successfully surveyed from the ground surface to the water table. Four of the 16 gamma-ray logs obtained outside the tank farms in Waste Management Area B-BX-BY suggest that gamma-emitting radionuclides may have redistributed in sediments surrounding these four boreholes in the last 10 years.
Movement of small amounts of cobalt-60 at one 200-East Area well was inferred in a small zone between 33.2 and 34.7 m (109 and 114 ft), but the movement is interpreted to be horizontal (away from the borehole) not vertical (toward the water table). Recent logging of another 200-East Area well showed very minor changes in cobalt-60 at 37.2 and 42.1 m (122 and 138 ft). The cobalt appears to have moved deeper down the profile. The magnitude of the vertical migration was less than 1 pCi/g of cobalt-60. The amount of cobalt-60 migration is small at both locations and is not a significant risk.
Uranium from Hanford operations was identified in two 200-East Area wells at orders of magnitude higher than natural background concentrations. The uranium moved deeper in the last 10 years and, currently, is just above the water table. Groundwater at these wells has been showing rising uranium concentrations for the last 5 years. Uranium in deep sediments between 70.7 and 75.9 m (232 and 249 ft) appeared in the September 1997 log at one of the 200-East Area wells. Uranium in the sediments at another well increased by a factor of 5 (from 200 to 1,000 pCi/g) in a deep zone between 67.1 and 73.2 m (220 and 240 ft). The peak activity and whole plume seem to have migrated 1.2 to 6.1 m (3.9 to 20 ft) deeper into the profile. The significance of the uranium migration at these two locations, which are separated by approximately 100 m (328 ft), is under investigation. The source of the uranium may not be common for these two wells. Single-shell tank BX-102 is a likely source of the uranium in one of the wells.
Soil vapor extraction is being used to remove the carbon tetrachloride source from the vadose zone as part of the 200-West Area carbon tetrachloride expedited response action being conducted by Bechtel Hanford, Inc. To track the effectiveness of the remediation effort, measurements of soil-gas concentrations of chlorinated hydrocarbons were made at individual on-line extraction wells, at soil-gas probes throughout the vadose zone, and at the inlets to the three soil vapor extraction systems.
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 contaminant sources (lower permeability zones such as the lower Hanford formation silt and Plio-Pleistocene layers). 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. The extraction systems are estimated to have removed 6% of the residual mass at the 216-Z-1A/216-Z-18 Well Fields and 21% of the residual mass at the 216-Z-9 Well Field. The location of the remaining carbon tetrachloride sources in the various strata is a result of its initial accumulation in the finer grained, lower permeability sediment and the relative inability of the extraction system to induce airflow through this lower permeability zone to effectively remove soil vapor.
Carbon tetrachloride concentrations measured in soil vapor near the water table increased relatively slowly during the rebound study and remained relatively constant during restart in July 1997. These relatively slow changes during the rebound study suggest that the volatilization of dissolved carbon tetrachloride from groundwater into the unsaturated zone, and/or the downward migration of carbon tetrachloride from the lower permeability zone toward the groundwater, was occurring slowly relative to the 8-month-long rebound study. The measured carbon tetrachloride vapor concentrations are an order of magnitude lower than the equilibrium vapor concentrations predicted for groundwater concentrations using Henry's Law. The vapor concentrations are also much lower than saturated vapor concentrations in equilibrium with a carbon tetrachloride nonaqueous-phase liquid, which suggests that the continuous carbon tetrachloride contamination source indicated for the groundwater at the 216-Z-9 Well Field may be within the aquifer rather than draining from the vadose zone sediments. The results obtained to date suggest that vapor-phase transport is secondary to dense nonaqueous-phase liquid as a groundwater contamination pathway, but field measurements of carbon tetrachloride vapor concentrations are not completely consistent with numerical modeling results.
Groundwater monitoring below the carbon tetrachloride disposal units suggests there is a continuing groundwater source that produces somewhat uniform carbon tetrachloride concentrations with depth in the aquifer. A dense nonaqueous-phase liquid that has drained from the vadose zone into the aquifer and is slowly dissolving could produce such a pattern. The continuing presence of relatively high dissolved carbon tetrachloride concentrations in groundwater in the immediate vicinity of the 216-Z-9 Trench, 35 years after termination of disposal operations, suggests that a dense nonaqueous liquid phase of carbon tetrachloride is slowly dissolving within the aquifer. Although this liquid phase may be slowly draining from the vadose zone to groundwater, the soil vapor concentrations monitored deep within the vadose zone suggest that extraction remediation may have removed much of the vadose zone source and that the continuing groundwater source is now within the aquifer. Carbon tetrachloride concentrations in the soil vapor and underlying groundwater do not appear to be in equilibrium, and the expected direction of carbon tetrachloride migration is from the groundwater to the vadose zone.
The Nonradioactive Dangerous Waste Landfill is a Resource Conservation and Recovery Act land disposal unit located approximately 5.6 km (3.5 mi) southeast of the 200-East Area. The landfill was used to dispose of nonradioactive dangerous waste and asbestos waste from 1975 to 1985. A soil vapor survey was conducted at the landfill during 1997 to assess the vertical extent of volatile organic compound contamination and the potential impacts to groundwater and to resample selected shallow vapor probes for changes in contaminant distribution that may indicate contaminant movement.
Six volatile organic compounds were detected during the 1997 survey: 1,1,1-trichloroethane, 1,1-dichloroethane, tetrachloroethylene, trichloroethylene, carbon tetrachloride, and chloroform. Of these contaminants, 1,1,1-trichloroethane was the most widespread and was detected in all but one of the samples from the deep probes at concentrations less than 1 part per million by volume (ppmv); however, 1,1,1-trichloroethane was not detected in the samples from the shallow probes. Carbon tetrachloride and chloroform were the only contaminants detected at concentrations exceeding 1 ppmv; in samples from two adjacent locations (one shallow and two deep probes within and beneath the chemical trenches). All of the same contaminants, except 1,1-dichloroethane, were detected in a 1993 survey.
Based on the 1997 results, the soil vapor contaminants tend to be distributed at low concentration levels within or south of the Nonradioactive Dangerous Waste Landfill trenches. The volatile organic compound concentrations detected in deep samples suggest that vertical migration of carbon tetrachloride occurred directly beneath the chemical trenches within a narrow zone. Comparison of analytical results for the 1993 and 1997 soil vapor samples collected from shallow probes indicates that the maximum carbon tetrachloride concentrations are still laterally within the chemical trenches at the landfill, suggesting that the contaminants have not migrated significantly laterally.
In 1997, 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 1997 from site operations was 0.01 mrem (0.1 µSv) compared to 0.007 mrem (0.07 µSv) calculated for 1996. The radiological dose to the population within 80 km (50 mi) of the site, estimated to be 380,000 persons, from 1997 site operations was 0.2 person-rem (0.002 person-Sv), which remained unchanged from the population dose calculated for 1996 (0.2 person-rem [0.002 person-Sv]). The average per-capita dose from 1997 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 0.04% of the EPA limit of 10 mrem/yr (0.1 mSv/yr).
Meteorological measurements are taken to support site emergency preparedness, site operations, and atmospheric dispersion calculations. Weather forecasting and maintenance and distribution of climatological data are provided.
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 wind speed for 1997 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 116 km/h (72 mi/h).
Precipitation for 1997 totaled 16.2 cm (6.4 in.), 102% of normal, with 19.8 cm (7.8 in.) of snow recorded.
Temperatures for 1997 ranged from -13.3°C (8°F) in January to 41.1°C (106°F) in August.
Management of archaeological, historical, and traditional cultural resources at the Hanford Site is provided in a manner consistent with the National Historic Preservation Act, Native American Graves Protection and Repatriation Act, Archaeological Resources Protection Act, and American Indian Religious Freedom Act. During 1997, 151 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. A similar monitoring study, focusing on eroding shorelines along the Columbia River, was also conducted during 1997. Mitigation of historic buildings and structures continued in 1997 as required by the programmatic agreement for the built environment and the historic district treatment plan.
Public involvement in the cultural resources program focused on the built environment and curation strategies for important Manhattan and Cold War Era artifacts and associated records. 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 1997.
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/annualrp97/summary.htm
Document
Number: PNL-11795
Document Date: September 1998
Posted: November
1998