The report is written to meet reporting 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
The Hanford Site was acquired by the federal government in 1943 and for many years 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:
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, and has begun to clean up and dispose of more than 100 facilities.
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 Hanford Site are managed by the 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, waste management, and monitoring of operations and effluents for environmental compliance.
The principal contractors include:
A key element in Hanford's compliance program is the Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement). The Tri-Party Agreement is an agreement among the U.S. Environmental Protection Agency (EPA), Washington State Department of Ecology (Ecology), and DOE for achieving compliance with the remedial action provisions of the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) (including Superfund Amendments and Reauthorization Act [SARA]) and with treatment, storage, and disposal unit regulation and corrective action provisions of the Resource Conservation and Recovery Act (RCRA).
The preliminary assessments conducted for the Hanford Site revealed approximately 1,100 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 selection of the operable units currently under investigation is a result of Tri-Party Agreement negotiations. The Hanford Site was in compliance with these CERCLA/SARA requirements in 1994.
To provide the public with the basis for emergency planning, Subtitle B of the Act contains requirements for periodic reporting on hazardous chemicals stored and/or used near the community. The 1994 Hanford Tier Two Emergency and Hazardous Chemical Inventory (DOE 1995a) was issued to the State Emergency Response Commission, local county emergency management committees, and local fire departments. The report contained information on hazardous materials in storage across the Hanford Site. The 1993 Hanford Toxic Chemical Release Inventory (DOE 1994b) was issued in July 1994 to the EPA and the state. This report contains information on releases to the environment of chemicals that were in excess of mandated thresholds. Accordingly, during 1994, the Hanford Site was in compliance with the reporting and notification requirements contained in this Act.
At the Hanford Site, over 60 treatment, storage, and disposal units have been identified that must be permitted or closed in accordance with RCRA and Washington State regulations. These units are required to operate under Ecology's interim-status compliance requirements. Approximately one-half of the units will be closed.
Subtitle I of RCRA deals with regulation of underground storage tank systems. These regulations were added to RCRA 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 nuclear waste tanks, which are regulated as treatment, storage, and disposal facilities.
The Washington State Department of Health, Division of Radiation Protection, Air Emissions and Defense Waste Section, has developed regulatory controls for radioactive air emissions under Section 116 of the Clean Air Act. Washington State regulations (Washington Administration Code [WAC] 246-247) require registration of all radioactive air emission point sources with the Washington State Department of Health. All significant Hanford Site stacks emitting radiation have been registered in accordance with applicable regulations.
Revised Clean Air Act requirements for radioactive air emissions were issued December 15, 1989, under National Emission Standards for Hazardous Air Pollutants, 40 Code of Federal Regulations 61 (40 CFR 61), Subpart H. Emissions from the Hanford Site are well within the new EPA offsite emissions standard of 10 millirem/year (effective dose equivalent [see Appendix B, "Glossary"]). Hanford Site sources are in the process of meeting the procedural requirements for flow measurement, emissions measurement, quality assurance, and sampling documentation.
Pursuant to this program, EPA has developed regulations specifically addressing asbestos emissions (40 CFR 61, Subpart M). These regulations apply at the Hanford Site in building demolition/disposal and waste disposal operations. During 1994, 2,063 cubic meters (72,860 cubic feet) of asbestos were removed.
The local air authority, the Benton-Franklin Counties Clean Air Authority, enforces Regulation 1. This regulation pertains to detrimental effects, fugitive dust, incineration products, open burning, odor, opacity, asbestos, and emissions. The Authority has also been delegated responsibility to enforce the EPA asbestos regulations under the National Emission Standards for Hazardous Air Pollutants. The Site remains in compliance with the regulations.
Several EISs related to programs or activities on the Hanford Site are in process or in the planning stage.
Wildlife inhabiting the Hanford Site is monitored to determine the status and condition of the populations, and to assess effects of Hanford Site operations. Particular attention is paid to species that are rare, threatened, or endangered nationally or statewide and those species that are of commercial, recreational, or aesthetic importance statewide or locally. These species include the bald eagle, chinook salmon, Rocky Mountain elk, mule deer, Canada goose, several species of hawk, and other bird species. Fluctuations in wildlife and plant species on the Hanford Site appear to be a result of natural ecological factors and management of the Columbia River system.
The Hanford Cultural Resources Laboratory was established by the Richland Operations Office in 1987 as part of the Pacific Northwest Laboratory. Cultural resources on the Hanford Site are closely monitored, and projects are relocated to avoid sites in cases where there is a possibility of altering any properties that may be eligible for listing on the National Register of Historic Places.
It appears that erosive processes and human activities are the most significant factors affecting most sites and buildings. Wind erosion from off-road vehicle use and vandalism plays a big part in the deterioration of sites inside and outside the Site boundary while alteration or demolition activities cause impacts to buildings and/or structures.
The community-operated environmental surveillance program was initiated in 1990 to increase the public's involvement in and awareness of Hanford's surveillance program. Three surveillance stations continued operation in 1994.
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.
The following sections discuss the doses calculated from environmental data, and effluent monitoring and environmental surveillance on or near the Hanford Site in 1994.
The potential dose to the hypothetical maximally exposed individual (MEI) in 1994 from Hanford operations
was 0.05 mrem (
), compared to 0.03 mrem (
) calculated for 1993. The
potential dose to the local population of 380,000 persons from 1994 operations was 0.6 person-rem (0.006
person-Sv), compared to 0.4 person-rem (0.004 person-Sv) reported for 1993. The 1994 average dose to the
population was 0.002 mrem (
) per person. The current DOE radiation limit for an individual
member of the public is 100 mrem/yr (1 mSv/yr), and the national average dose from natural sources is 300
mrem/yr (3 mSv/yr). The MEI potentially received 0.05% of the DOE dose limit and 0.02% of the national
average background dose from natural sources. The average individual potentially received 0.002% of the
standard and
of the 300 mrem/yr received from typical natural sources.
Special exposure scenarios not included in the above dose estimates include the potential consumption of game residing on the Hanford Site and exposure to radiation at the publicly accessible location with the maximum exposure rate. Doses from these sources would also have been small compared to the dose limit.
Dose through the air pathways was 0.1% of the EPA limit of 10 mrem/yr (40 CFR 61).
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 total alpha and total beta activity and, as warranted, specific gamma-emitting radionuclides. Nonradioactive hazardous constituents are also monitored, as applicable.
Radioactive effluents from many facilities on the Site are approaching levels practically indistinguishable from the natural occurring radioactivity present everywhere. This decrease translates to a very small offsite radiation dose attributable to Site activities. A new 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 1994 are not significantly different from totals in 1993.
Specifically, the near-facility environmental monitoring 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 decontaminating or decommissioning. External radiation dose, ambient air particulates, soil, surface water, sediment, and biota were sampled. Parameters included, as appropriate, radionuclides, radiation exposure, hazardous constituents, pH, and water temperature.
The analytical results showed a large degree of variability; in general, the samples collected from media located on or directly adjacent to the waste disposal and other nuclear facilities had significantly higher concentrations than those farther away. As expected, certain radionuclides were found in higher concentrations within different operational areas. Generally speaking, the predominant radionuclides were activation products/gamma emitters in the 100 Areas, fission products in the 200/600 Areas, and uranium in the 300 Area.
Air Monitoring. Radioactivity in air was sampled by a network of continuously operated samplers at 41 locations near facilities: 4 located in the 100-K Area, 4 located in the 100-N Area, 31 in the 200/600 Areas, one located near the 300 Area Treated Effluent Disposal Facility, 1 station collocated with the Surface Environmental Surveillance Project and the Washington State Department of Health at the Wye Barricade. Air samplers were primarily located at or near sites and/or facilities having the potential or history for release, with an emphasis on the prevailing downwind directions. Of the radionuclide analyses performed, cesium-137, plutonium-239,240, strontium-90, and uranium were consistently detectable in the 200 Areas; cobalt-60 was detectable in the 100-N Area. Air concentrations for these radionuclides were elevated near facilities when compared to the concentrations measured offsite by the Surface Environmental Surveillance Project.
Monitoring of Surface-Water Disposal Units and Springs. Sampling of surface-water disposal units included water, sediment, and aquatic vegetation. Samples taken at river shoreline springs included water only. Radiological analysis of liquid samples from surface-water disposal units included plutonium-239,240, total alpha, total beta, tritium, and gamma-emitting radionuclides. Radiological analysis of sediment and aquatic vegetation included plutonium-239,240, strontium-90, uranium, and gamma-emitting radionuclides. Nonradiological analysis performed included pH, temperature, and nitrates.
Radionuclide concentrations in surface-water disposal units were below the applicable Derived Concentration Guides used as indexes of performance and in most cases at or below the analytical detection limit. Although some elevated levels were seen in both aquatic vegetation and sediment, in all cases the radiological analytical results were well below the standards for radiological control. The results for pH were well within the pH range of 2.0 - 12.5 standard for liquid effluent discharges as required by RCRA. The analytical results for nitrates were all below the 45-mg/L Drinking Water Standard.
Ground-water springs along the 100-N Area shoreline are sampled to verify the reported radionuclide releases to the Columbia River from past operations of the N Reactor. By characterizing the radionuclide concentrations in the springs along the shoreline, the results can be compared to the concentrations measured in the facility effluent monitoring well.
In 1994, the concentrations detected in the springs samples were highest in those springs nearest the facility effluent monitoring well, although the springs concentrations were considerably lower than those measured in the well.
Radiological Surveys. There were approximately 2,756 hectares (6,364 acres) of outdoor posted surface contamination and 981 hectares (2,423 acres) of posted underground radioactive material sitewide in 1994. These areas were typically associated with cribs, burial grounds, tank farms, and covered ponds, trenches, and ditches. The number of posted surface contamination areas varied because of an ongoing effort to clean, stabilize, and remediate areas of known contamination while new areas of contamination were being identified. New areas may have been identified because of contamination migration or the increased effort being made to investigate outdoor areas for radiological contamination. It was estimated that the external dose rate for 80% of the identified outdoor surface contamination areas was less than 1 millirem/hour, although isolated radioactive specks (less than 0.6 centimeters or 0.25 inches) could be considerably higher. Contamination levels of this type would not significantly add to external dose rates for the public or Site employees.
Soil and Vegetation Monitoring. Soil and vegetation samples were also collected on or adjacent to waste disposal units and from locations downwind and within the operating environment of facilities. Special samples were taken where physical or biological transport problems were identified. Soil and vegetation sample concentrations for some radionuclides were elevated near facilities when compared to the concentrations measured offsite. The concentrations show a large degree of variance; in general, samples collected on or directly adjacent to waste disposal facilities had significantly higher concentrations than those collected farther away.
External Radiation. External radiation fields were surveyed near operating facilities and waste-handling, storage, and disposal sites to measure, assess, and control the impacts of operations.
Hand-held microroentgen meters (to measure low-level radiation exposure) were used in the 100-N Area to survey points near and within the N Springs area, 1301-N Liquid Waste Disposal Facility, and 1325-N Liquid Waste Disposal Facility. The radiation rates measured in the N Springs area continued to decline in 1994, reflecting discontinued discharges to the 1301-N Liquid Waste Disposal Facility and the continuing decay of its radionuclide inventory. Radiation measurements taken at the 1325-N Liquid Waste Disposal Facility in 1994 and in the previous years were slightly elevated. Discontinued discharges to the facility resulted in the loss of the water that formerly provided shielding for the gamma-emitting radionuclides in sediments of the facility.
Radiation levels measured with thermoluminescent dosimeters were highest near facilities that had contained or received liquid effluent from N Reactor, primarily the 1325-N Liquid Waste Disposal Facility and the 1301-N Liquid Waste Disposal Facility. Dose rates for 1994 for these two facilities decreased approximately 5% compared to 1993.
The highest dose rates measured in the 200/600 Areas were near waste-handling facilities such as tank farms. The average annual dose rate for 1994 in the 200/600 Areas was 160 mrem/year, which was a decrease of 6% when compared to 1993.
The highest dose rates measured in the 300 Area were near waste-handling facilities such as the 340 Waste Handling Facility. The average annual dose rate for 1994 in the 300 Area was 170 mrem/year, which was a 15% decrease of the average dose rate of 200 mrem/year measured in 1993.
The highest dose rates measured in the 400 Area were near the main gate of the Fuels and Materials Examination Facility. The average annual dose rate for 1994 in the 400 Area was 110 mrem/year, an increase of 12% of the average annual dose rate of 98 mrem/year in 1993.
For 1994, no differences were observed between the annual average total beta air concentrations measured at the Site perimeter and distant community locations. Air concentrations of total alpha are slightly elevated at the Site perimeter and nearby communities were within the range of historical values. Numerous specific radionuclides in quarterly composite samples were analyzed using gamma scan analysis; however, no radionuclides of Hanford origin were detected consistently.
Tritium concentrations for 1994 were similar to values reported for previous years and did not show the highly elevated and variable results reported for 1991 and 1992. The tritium samples collected from January to May 1992 may have been contaminated during the analytical process because most locations including the distant communities reported unusually high concentrations. Tritium concentrations for 1994 were elevated for two individual samples but consistently elevated concentrations were not seen at any location, and there was little difference between concentrations at the distant locations and those at the Site perimeter.
Air concentrations of plutonium-238, 239,240, and strontium-90 for samples collected both onsite and offsite were below detection limits. Average uranium concentrations in airborne particulate matter were similar at the Site perimeter and distant locations. Iodine-129 concentrations were statistically elevated at the Site perimeter relative to the distant locations indicating a measurable Hanford source; however, the average concentration at the Site perimeter was only 0.000002% of the Derived Concentration Guide of 70 picocuries/cubic meter. The Derived Concentration Guide is the air concentration that would result in a radiation dose equal to the DOE public dose limit (100 millirem/year).
Air samples were collected at several Hanford Site locations for volatile organic compounds. All measured air concentrations of these organic compounds were well below applicable occupational maximum allowable concentration standards for air contaminants for these compounds. No ambient air standards are currently available.
Although radionuclides associated with Hanford operations continued to be routinely identified in Columbia River water during the year, concentrations remained extremely low at all locations and were well below applicable standards. The concentrations of tritium were significantly higher (5% significance level) at the Richland Pumphouse (downstream from the Site) than at Priest Rapids Dam (upstream from the Site), indicating a contribution along the Hanford Reach. For chemical water quality constituents measured in Columbia River water during 1994, metals and anions were generally similar upstream and downstream and in compliance with applicable primary drinking water standards. Volatile organic compounds were generally less than analytical detection levels.
During 1994, samples were collected from seven Columbia River shoreline springs, contaminated as a result of past waste disposal practices at the Hanford Site. Contaminant concentrations in the springs were similar to those found in the ground water. All radionuclide concentrations measured in riverbank springs in 1994 were less than applicable DOE Derived Concentration Guides. However, strontium-90 in the 100-D and 100-H Areas, tritium in the 100-N Area and along the old Hanford Townsite, and total alpha in the 300 Area exceeded Washington State and federal Drinking Water Standards. Total uranium exceeded the Site-specific proposed EPA Drinking Water Standard in the 300 Area. Chromium and nitrate in the 100-D Area spring were the only nonradiological contaminants measured in riverbank springs in 1994 that exceeded Drinking Water Standards.
Samples of Columbia River surface sediments were collected from behind McNary Dam (downstream from the Site) and Priest Rapids Dam and from four shoreline locations along the Hanford Reach of the Columbia River during 1994. As in the past, radionuclide concentrations in sediments behind McNary Dam were generally higher than those observed in sediments collected from behind Priest Rapids Dam and along the Site.
Three onsite ponds were sampled to determine radionuclide concentrations. These ponds are accessible to migratory waterfowl and other animals. As a result, a potential biological pathway exists for the removal and dispersal of contaminants that may be in the ponds. Concentrations of radionuclides in water collected from these ponds during 1994 were similar to those observed during past years. With the exception of uranium-234 and -238 in the July sample of West Lake, radionuclide concentrations in the onsite pond water were below applicable DOE Derived Concentration Guides.
Offsite water, used for irrigation and/or drinking water, was sampled in 1994 to determine radionuclide concentrations in water used by the nearby public. Elevated total alpha and total beta concentrations, attributed to naturally occurring uranium, were observed at some locations. All radionuclide concentrations measured in offsite water supplies and irrigation water were below applicable DOE Derived Concentration Guides and applicable Drinking Water Standards. The proposed EPA Drinking Water Standard for total uranium, however, was exceeded at Alexander Farm. Radionuclide concentrations in offsite irrigation water were similar to those observed in the Columbia River.
An evaluation of potential Hanford impacts was made by comparing onsite and offsite results. No statistical differences in analytical results were identified.
In 1994, four onsite, one distant, and four perimeter locations were sampled for perennial vegetation. Vegetation results were compared using the same rationale as soil sampling. Radionuclides, potentially from the Hanford Site, consistently detected in vegetation samples were strontium-90, uranium-238, and plutonium-239,240. Cesium-137 was also detected in four of the nine samples. A statistical difference was noted between Cesium-137 concentrations at onsite and perimeter locations and offsite and onsite locations. A difference was also seen in uranium-238 concentrations in samples collected on and off the Site. In a special study of Columbia River milfoil, a nuisance aquatic plant, slightly elevated concentrations of uranium-238 were found in plants growing near the 300 Area.
No offsite accumulation of radionuclides of Hanford origin was identifiable from the soil and vegetation samples collected and analyzed in 1993.
Analysis of wildlife for radioactivity indicated that some species had accumulated levels of radioactivity greater than background levels. Background samples collected for a number of species over the past 4 years are summarized in this year's report. Strontium-90 was detected in deer and rabbit bone as well as Columbia River fish carcasses at levels exceeding concentrations reported in background locations. Cesium-137 was detected at higher concentrations in the muscle of deer collected in 1992 from a background location in Stevens County, north of Spokane, than has been observed in Hanford Site populations of mule deer. The levels of cesium-137 in the deer from Stevens County were attributed to past atmospheric fallout from weapons testing. Collectively, the observations of radioactivity in Hanford fish and wildlife indicate accumulation of small amounts of specific radionuclides originating from the Hanford Site.
The radionuclide concentrations measured in fish and wildlife were used to estimate potential doses to hunters and fishers who might have consumed Hanford Site game. The resulting doses were much less than applicable guidelines developed to protect the public.
Most of the farm products sampled did not contain measurable concentrations of radionuclides. Tritium was measured at levels very close to the detection level, and there was no apparent upwind or downwind effect noted. Iodine-129 was found at slightly elevated levels in downwind milk samples, but the levels were very low and have been decreasing over the past 6 years.
The average background radiological dose rate, calculated from TLDs at Yakima and Sunnyside (both locations are distant and upwind relative to Hanford), was 96 " 8 mrem/year as compared to the average downwind perimeter dose rate of 110 " 9 mrem/year. These represent an approximate 8% decrease in the background and a 9% increase in the perimeter locations when compared to 1993 measurements. Dose rates at the Columbia River shoreline near the 100-N Area were approximately two times the typical shoreline dose rates and the higher dose rates may be attributable to radiation from the 100-N Area liquid waste disposal facilities. Onsite dose rates measured near operational areas were higher than the average background dose rate.
Analytical results for samples were compared with EPA's Drinking Water Standards (Tables C.2 and C.3, Appendix C) and DOE's Derived Concentration Guides (Table C.6, Appendix C). Ground water beneath the Hanford Site is used for drinking at five locations. Only the drinking water in the 400 Area at the FFTF Visitors Center is available for public consumption; this source is discussed in Section 5.8. In addition, water supply wells for the city of Richland are located adjacent to the southern boundary of the Hanford Site.
Radiological monitoring results indicated that cesium-137, cobalt-60, iodine-129, strontium-90, technetium-99, total alpha, total beta, tritium, uranium, and plutonium concentrations were detected in levels greater than the Drinking Water Standard in one or more wells onsite. Concentrations of tritium greater than the Derived Concentration Guide were detected in the 200 Areas. Concentrations of strontium-90 greater than the Derived Concentration Guide were detected in the 100-N Area and 200-East Area. Concentrations of uranium greater than the Derived Concentration Guide were detected in the 200-West Area. Plutonium concentrations greater than the Derived Concentration Guide were detected in the 200-East Area.
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 but at levels less than the Drinking Water Standard. The spread of this plume farther south than the 300 Area is restricted by the ground-water flow away from the Yakima River and the North Richland well field. Ground water with tritium at levels above the Drinking Water Standard also discharges to the Columbia River in the 100-N Area and immediate vicinity. A small but high concentration tritium plume near the 100-K East Reactor also may discharge to the river. Tritium at levels greater than the Drinking Water Standard was also found in the 100-D and 100-F Areas.
Cobalt-60 was detected in the northeastern part of the 200-East Area and parts of the surrounding 600 Area but at levels less than the Drinking Water Standard. Cobalt-60 detections in the 100-N Area at levels greater than the Drinking Water Standard appear to be related to high suspended sediments in the samples and are not indicative of ground-water concentrations.
Concentrations of strontium-90 at levels greater than the Derived Concentration Guide were measured in the 100-N Area. This plume discharges to the Columbia River. A localized area in the 200-East Area also contains ground water with strontium-90 at levels greater than the Derived Concentration Guide. Strontium-90 at levels greater than the Drinking Water Standard is found in the 100-B, 100-F, 100-H, and 100-K Areas. These plumes extend to the Columbia River. Only one well in the 100-D Area showed strontium-90 at levels greater than the Drinking Water Standard.
Technetium-99 at concentrations greater than the Drinking Water Standard was found in the northeastern part of the 200-East Area and adjacent 600 Area. Technetium-99 was also detected at levels greater than the Drinking Water Standard in the 200-West Area and extends into the 600 Area.
Iodine-129 was detected at levels greater than the Drinking Water Standard in the 200-East Area and in an extensive part of the 600 Area to the east and southeast. The iodine-129 and tritium share common sources; however, there is no indication that iodine-129 is present at concentrations greater than the Drinking Water Standard in the ground water currently discharging to the Columbia River. Iodine-129 at levels greater than the Drinking Water Standard also extends into the 600 Area to the northwest of the 200-East Area. The southern part of the 200-West Area is also a source of iodine-129 extending into the 600 Area. There is a less extensive iodine-129 plume at levels greater than the Drinking Water Standard in the north-central part of the 200-West Area.
Cesium-137 was only detected in the 200-East Area. The concentrations detected were greater than the Drinking Water Standard but were restricted to the immediate vicinity of one well.
Uranium was detected at levels greater than the Drinking Water Standard in wells in the 100-F, 100-H, 200-East, 200-West, and 300 Areas. Ground water with uranium concentrations greater than the Drinking Water Standard appears to be discharging to the Columbia River from the 100-H and 300 Areas. One well in the 200-West Area had concentrations greater than the Derived Concentration Guide.
Plutonium was only detected in ground-water samples near one well in the 200-East Area. There is no explicit Drinking Water Standard for plutonium; however, the levels were greater than the Drinking Water Standard for gross alpha.
Certain nonradioactive chemicals regulated by the EPA and the State of Washington were also present in Hanford Site ground water. These constituents were also characterized by the monitoring programs.
Nitrate concentrations exceeded the Drinking Water Standard at locations in all 100 Areas with the exception of the 100-B Area. Those ground-water plumes discharge to the Columbia River. Nitrate 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 Drinking Water Standard. Nitrate is present at levels greater than the Drinking Water Standard in the 200-West Area and adjoining 600 Area locations. Some of the nitrate in the 600 Area, 1100 Area, and North Richland area is believed to result from offsite sources.
Fluoride was measured at levels greater than the primary Drinking Water Standard in the 200-West Area.
Chromium was found at levels greater than the Drinking Water Standard in the 100-D, 100-F, 100-H, and 100-K Areas.
An extensive plume of carbon tetrachloride at levels greater than the Drinking Water Standard was found in ground water at the 200-West Area and extends into the 600 Area. This plume is associated with a less extensive plume of chloroform which may be a degradation product of the carbon tetrachloride. Maximum chloroform levels are also greater than its Drinking Water Standard.
Trichloroethylene was found at levels greater than the Drinking Water Standard in the 100-F Area and in the 600 Area to the west. Trichloroethylene was also detected at levels greater than the Drinking Water Standard in the 100-K and 200-West Areas. Trichloroethylene in the 300 Area was also measured at levels greater than the Drinking Water Standard.
Samples from one monitoring well in the deeper confined aquifer in the 100-B Area contained no strontium-90 at levels greater than the Drinking Water Standard. A few wells near source areas exhibited impacts of past site disposal practices.
A comprehensive review of all ground-water monitoring work on the Site is published annually. Before 1989, these reports contained complete listings of all radiological and chemical data collected during the reporting periods. Currently, complete listings for ground-water data can be found in a companion volume to this annual report and in data listings published by other programs.