5.13 CUMULATIVE IMPACTS
This section describes potential cumulative impacts associated with implementing the TWRS alternatives and other actions at the Hanford Site. The TWRS impacts described in this section include the impacts of both remediation of the tank waste and subsequent closure of the tank farms. The section identifies other actions that could impact the Hanford Site and, when possible, provides a qualitative or quantitative discussion of the potential cumulative impacts of the TWRS alternatives and the other actions.
The impacts of the tank waste and capsule alternatives described in previous sections would occur in the context of other past, present, and reasonably foreseeable activities at the Hanford Site. The National Environmental Policy Act (NEPA) implementation regulations define a cumulative impact as the impact on the environment that results from the incremental impact of the action when added to other past, present, and reasonably foreseeable future actions regardless of what agency (Federal or non-Federal) or person undertakes other such actions. Cumulative impacts can result from individually minor but collectively significant actions taking place over a period of time (40 CFR 1508.7).
As discussed in Section 5.0.4, post-remediation risk of TWRS EIS alternatives would be strongly influenced by the type and form of waste remaining in the tanks or on the Hanford Site following remediation, the amount of time and labor that would be needed to accomplish the alternative, and the environmental disturbance that would take place during the work, including permanent disturbance or long-term resource commitment. These factors were comprehensively analyzed and discussed throughout Section 5.0 for each resource for each of the TWRS alternatives. For purposes of discussing the potential cumulative impacts in this section, the TWRS alternative having the highest potential cumulative impacts was drawn from the comprehensive discussion and presented in combination with the other past, present, and reasonably foreseeable sources of impact. Thus the upper bound of the reasonably foreseeable potential cumulative impacts is presented.
Actions at the Hanford Site that would have quantifiable environmental impacts that would be cumulative with TWRS actions include the Hanford Site waste management and remedial action programs, the Environmental Restoration and Disposal Facility, the management of spent nuclear fuel stored in the K Basins, the US Ecology Site, and the replacement cross-site transfer system. While these activities would occur in the same general time frame as the EIS alternatives, little quantifiable cumulative impacts of the TWRS alternatives and other projects would be expected. Among the cumulative impacts that would occur would be impacts to land use and biological resources, human health, air quality, groundwater quality, and socioeconomics.
5.13.1 Actions at Other DOE Sites or Facilities and Programmatic Actions that Could Potentially Impact the Hanford Site
Programs or actions at other DOE sites and DOE programmatic evaluations that could impact the Hanford Site are described in this section.
Waste Management Programmatic EIS
DOE will determine what type, size, and number of waste storage, treatment, and disposal facilities will be needed for DOE waste and where to build them. This would include determining the transportation network; i.e., deciding what sites would ship to other sites for treatment, storage, and disposal.
Under the Waste Management Programmatic EIS, the Hanford Site is an alternative site for centralized or regionalized management of DOE waste (DOE 1995e). The Hanford Site would manage its own waste (decentralized alternative), receive waste from offsite (regional or centralized alternatives), or ship waste to another DOE or commercial waste management facility (regional or centralized alternatives).
In the EIS, DOE considered a broad spectrum of hazardous and radioactive waste management issues at the Hanford Site. The highest level of adverse impacts at the Hanford Site and the surrounding region would result from alternatives in which treatment and disposal facilities would be constructed for the Hanford Site to manage its own waste, in addition to accepting waste from offsite DOE facilities for treatment, disposal, or storage. Offsite waste received would include LAW and low-level mixed waste for treatment and disposal, transuranic waste for treatment, and HLW canisters for storage. The lowest level of adverse impacts of the waste management alternatives would be those in which the Hanford Site would package and ship its waste for offsite disposal, or would receive only small quantities of waste for treatment and disposal from other sites.
The Hanford Site-specific impacts under the DOE Waste Management Program alternatives would be primarily confined to the Central Plateau, the same area where proposed TWRS activities analyzed in the TWRS EIS would occur. Potential cumulative impacts of conducting waste management activities on the Central Plateau would involve increased land use, habitat, health effects, air quality, water quality, transportation, and socioeconomic impacts.
Disposal of Decommissioned, Defueled Cruiser, Los Angeles Class, and Ohio Class Naval Reactor Plants
The final EIS, prepared by the U.S. Navy, evaluates the potential impacts of disposing of defueled reactor plants from decommissioned naval vessels (Navy 1996). The preferred alternative is land burial at the low-level waste burial grounds at the Hanford Site. DOE is a cooperating agency in the preparation of this EIS.
5.13.2 Actions Adjacent to the Hanford Site
In addition to DOE waste management activities, there are other nuclear facilities at or near the Hanford Site that could contribute to radioactive releases. These facilities include a commercial radioactive waste burial site, a commercial nuclear power plant, a nuclear fuel production plant, a commercial low-level radioactive waste compacting facility, and a commercial decontamination facility. The ongoing operations of these facilities would have cumulative impacts with the proposed TWRS activities in areas such as socioeconomics, air and water emissions, transportation, and land use.
DOE actions near the Columbia River could be affected by the U.S. Department of Interior's proposal to designate the Hanford Reach of the Columbia River as a Recreational River under the Wild and Scenic Rivers Act. DOE was a cooperating agency with the U.S. Department of Interior in preparing the Hanford Reach of the Columbia River Final River Conservation Strategy EIS (NPS 1994). The U.S. Department of Interior published its Record of Decision and made its recommendation to Congress. Designation of the Hanford Reach as a Recreational River awaits congressional action.
5.13.3 Currently Planned or Reasonably Foreseeable DOE Actions at the Hanford Site
This section describes the currently planned and reasonably foreseeable actions originating at the Hanford Site with potential cumulative impacts. Actions are identified in the context of the existing, ongoing, or planned activities. The activities are grouped into actions on the Central Plateau and actions in other Hanford Site areas. A number of proposed actions at the Hanford Site are being evaluated in environmental assessments, as detailed in the Draft 1995 Hanford Mission Plan (DOE 1994g). At present, it is not possible to include a quantitative analysis of all the impacts from these projects in this analysis because evaluation of many of these projects is not complete. However, these projects may contribute to cumulative future impacts from proposed remedial actions in the geographic areas considered in this EIS.
5.13.3.1 Central Plateau
The major impacts from the proposed TWRS alternatives would occur on the Central Plateau in the 200 Areas from 1997 to 2028, although tank farm closure actions would occur later.
Closure
Closure of the SSTs and DSTs is beyond the scope of this EIS. However, closure options could be interrelated with the TWRS alternative that is selected for implementation and the long-term impacts of the alternatives would be influenced by closure actions. Due to a lack of information, decisions on the appropriate type of tank farm closure cannot be made at this time. However, the long-term impacts of closure are reasonably foreseeable, and therefore are discussed in this section. Closure options range from clean closure, in which the tanks and all associated waste would be removed from the tank farm areas and disposed of onsite or offsite, to leaving the tanks and most of the tank waste in-place as described in the In Situ Vitrification and the In Situ Fill and Cap alternatives. Tank farm closure methods would be determined when the overall long-term land-use policies were established at the Hanford Site. The impacts of closing existing TWRS sites are also related to other major waste disposal facility closure issues on the Central Plateau. For purposes of calculating the reasonably foreseeable long-term impacts of the TWRS alternatives it has been assumed that closure would consist of emplacement of engineered barriers over waste left or placed in the near surface soils. Ultimate closure decisions would affect long-term land use of the Hanford Site. Long-term land use and ongoing Hanford Site operational issues will be addressed in the Hanford Remedial Action EIS and the Site's Comprehensive Land Use Plan, both of which are being prepared, and the planned Hanford Sitewide EIS.
Environmental Restoration Disposal Facility
The Environmental Restoration Disposal Facility, which has been constructed adjacent to the 200 Areas, provide s for the safe storage and disposal of waste generated during environmental restoration activities at the Hanford Site (DOE 1994h). The Environmental Restoration Disposal Facility, a large double-lined subsurface trench, serve s as the disposal facility for most of the waste excavated during remediation of waste management units at the Hanford Site. Waste generated from remediating Comprehensive Environmental Response, Compensation, and Liability Act past practice units and RCRA closure and corrective action activities will be placed in the Environmental Restoration Disposal Facility. Only waste that originates within the Hanford Site will be placed in the facility. The waste is expected to consist of hazardous, radioactive, and mixed waste. The Environmental Restoration Disposal Facility site will cover as much as 4.1 km2 (1.6 mi2) on the Central Plateau, approximately in the center of the Hanford Site, southeast of the 200 West Area and southwest of the 200 East Area.
Under current climate conditions, none of the contaminants that would be placed in the Environmental Restoration Disposal Facility are expected to reach groundwater within 10,000 years. The shrub-steppe habitat at the Environmental Restoration Disposal Facility site is considered priority habitat by Washington State. The disturbed area includes the Environmental Restoration Disposal Facility site itself (including the trench, stockpiling areas, roads, and supporting facilities), a borrow area, and a rail line right-of-way. Environmental Restoration Disposal Facility impacts that might be cumulative with TWRS alternatives include land use, habitat, air quality, transportation, and socioeconomic impacts.
Safe Interim Storage of Hanford Tank Waste
As described in Section 3.2.1.6, DOE decided to implement most of the actions of the preferred alternative, which were evaluated in the Safe Interim Storage of Hanford Tank Waste EIS (DOE 1995i). The actions will involve the continued operation of the existing cross-site transfer system between 200 West and 200 East Area tank farms until replaced by construction and operation of a new replacement cross-site transfer system and the continued operation of the mixer pump installed in tank 241-SY-101 to mitigate the unacceptable accumulation of hydrogen and other flammable gases. In the interim period prior to making and implementing decisions based on the TWRS EIS, the replacement cross-site transfer system would be used to transfer liquid waste from interim stabilization of SSTs and waste generated by 200 West Area facilities. Construction of the replacement cross-site transfer system began in late 1995 and is to be completed in 1998. Safe interim storage impacts identified in the Safe Interim Storage of Hanford Tank Waste EIS that might be cumulative with TWRS alternatives include land use and habitat.
Hanford Site Plutonium Finishing Plant Stabilization
DOE evaluated alternatives to convert plutonium-bearing materials at the Plutonium Finishing Plant Facility into a more stable, safer form and to reduce potential environmental and worker safety risks.
The Plutonium Finishing Plant Stabilization Final EIS was published in May 1996 (DOE 1996d) and a Record of Decision was issued in July 1996 (DOE 1996c). DOE decided to initiate removal of plutonium-bearing material in hold-up at the Plutonium Finishing Plant Facility and to initiate the stabilization of this and other plutonium-bearing material at the facility . Impacts that may be cumulative with TWRS alternatives include health effects and socioeconomics.
Waste Receiving and Processing Facility
During 1994, construction was started on the first major solid waste processing facility associated with Hanford Site cleanup. Scheduled to begin operations in March 1997, the Waste Receiving and Processing Facility Module 1 will be used to analyze and prepare for disposal, drums, and boxes of waste resulting from plutonium operations at the Hanford Site. Some of the materials processed will qualify as LAW suitable for disposal directly at the Hanford Site. The remaining waste will be certified as transuranic waste and packaged for eventual shipment to the Waste Isolation Pilot Plant in Carlsbad, New Mexico. Materials requiring further processing to meet disposal criteria will be retained at the Hanford Site pending treatment.
The 4,800-m2 (52,000-ft2) facility will begin operations in 1997 near the Central Waste Complex in the 200 West Area. The facility is designed to process 6,800 drums of waste annually for 30 years. No potentially cumulative impacts have been identified at this time for this action.
Effluent Treatment Facility and Liquid Effluent Retention Facility
Th ese facilit ies will provide for collection, retention, and treatment if necessary, of liquid waste before it is discharged to the soil column through a Washington State-approved land disposal site north of the 200 West Area. An evaluation of the Effluent Treatment Facility indicated that no significant impacts would result (DOE 1992c). Therefore, no potentially cumulative impacts have been identified at this time for this action.
US Ecology Low-Level Radioactive Waste Disposal Facility
The US Ecology Low-Level Radioactive Waste Disposal Facility occupies 40 ha (100 ac) of land leased by DOE to Washington State. US Ecology subleases the land from the State. The facility is located just southwest of the 200 East Area and receives low-level waste from commercial organizations. US Ecology began operating in 1965 and since that time has received a total of approximately 3.4E+05 m3 (1.3E+07 ft3) of commercial low-level waste through December 1994. This waste consists of solid or solidified material, contaminated equipment, cleaning waste, tools, protective clothing, gloves, laboratory waste, and naturally occurring or accelerator- produced radioactive material containing about 2.2 million curies. All waste and waste containers have been emplaced in trenches excavated into the surficial sediments. When completely filled, each trench is covered with at least 2.4 m (8 ft) of soil and capped with a layer of gravel (Ledoux 1995). US Ecology is assumed to continue to receive and emplace commercial low-level waste through the year 2063 (Jacobs 1996). Impacts that might be cumulative with TWRS alternatives include land use, groundwater, and transportation.
5.13.3.2 Other Hanford Site Areas
Hanford Remedial Action Program
The Hanford Remedial Action Program encompasses remediating contaminated soil and groundwater, decommissioning and decontaminating structures, and closing treatment, storage, and disposal facilities. Much of the waste to be generated by environmental restoration activities at the Hanford Site would be placed in the Environmental Restoration Disposal Facility. The Hanford Remedial Action EIS (DOE 1996c ) examine s these needs primarily in the context of DOE's responsibilities under RCRA, the Comprehensive Environmental Response, Compensation, and Liability Act, and the Tri-Party Agreement (Ecology et al. 1994).
The Hanford Remedial Action EIS compare s alternatives for land use including no action, unrestricted use, restricted use, and exclusive-use scenarios for various areas of the Hanford Site. The EIS analysis divide s the Hanford Site into four geographic areas and evaluate s the land-use alternatives for each of those areas. The Hanford Remedial Action Draft EIS has been published for public review .
Waste generated by the Hanford Remedial Action Program would be disposed of in the Environmental Restoration Disposal Facility on the Central Plateau. Impacts that might be cumulative with TWRS alternatives include land use, habitat, groundwater, traffic, and socioeconomics.
Decommissioning Eight Surplus Production Reactors
Present and foreseeable actions in the 100 Areas consist primarily of decommissioning the eight surplus production reactors along the Columbia River. DOE has decided on safe storage for 75 years or less, followed by one-piece removal of each reactor block and transport intact on a tractor-transporter from its present location in the 100 Areas to the 200 West Area for disposal. Contaminated materials associated with the fuel storage basins would also be disposed of in the 200 West Area, along with contaminated equipment and components associated with the reactors. Uncontaminated portions of the fuel storage basins would be removed to provide access for the tractor-transporter. Other uncontaminated structures and equipment would be demolished and placed in landfills in the vicinity of the reactor sites (DOE 1992b and DOE 1993j). Impacts that might be cumulative with TWRS alternatives include land use and habitat.
Management of Spent Nuclear Fuel Currently Stored in the K Basins
DOE evaluated alternatives to reduce risks associated with spent nuclear fuel and sludge currently stored in the water-filled K East and K West Storage Basins (K Basins). A Final EIS was issued in January 1996 and a Record of Decision was issued in March 1996. DOE decided to implement the preferred alternative, which consists of removing the spent nuclear fuel from the storage basins, drying, conditioning, and sealing the fuel in canisters, and storing the canisters in a new dry storage facility for up to 50 years pending decisions on ultimate disposition. The storage facility will be located in the 200 East Area on the Central Plateau. Impacts that might be cumulative with TWRS alternatives include land use, habitat, transportation, and socioeconomics.
5.13.4 Summary of Cumulative Impacts
Although many of the activities described previously would occur in the same general time frame as the TWRS EIS alternatives, little quantifiable cumulative impacts of the TWRS alternatives and other projects would be expected because of differences in the nature of the activities and their physical separation.
From certain broader environmental perspectives, cumulative impacts of the TWRS alternatives and other projects can be expected. For example, multiple projects each impacting a small amount of sensitive shrub-steppe habitat eventually could have a more substantial impact by fragmenting the habitat and reducing the total amount of shrub-steppe remaining on the Hanford Site. Cumulative impacts from groundwater would consist of a combination of 1) the existing groundwater contamination; 2) potential additional contamination from waste currently in the soils above the groundwater; and 3) potential additions from waste left in place or placed in the ground by future activities including TWRS alternatives.
Another area in which cumulative impacts could occur is on the socioeconomic environment. For example, if decisions are made that lead to constructing and operating facilities at the Hanford Site that currently are not foreseen, there would be additional employment and other economic benefits for the Tri-Cities area. However, there also could be additional population growth and the resulting burdens on public services and facilities such as schools, and impacts on the price and availability of housing. Table 5.13.1 presents a matrix of Hanford Site activities that overlap the proposed TWRS alternatives in time and location and could have cumulative impacts.
The proposed TWRS activities would be carried out against the baseline of overall Hanford Site operations. The TWRS alternatives and ongoing operations would have cumulative socioeconomic, land use, risk, and ecological impacts. The range of operational alternatives would be quantified in the planned Hanford Sitewide EIS. At this time, the magnitude of the additive impacts cannot be quantified. Assuming that the Hanford Site's environmental restoration and waste management mission does not change, it is likely that the future range of operational impacts would not be greater than the current impacts associated with Hanford Site waste and operations.
Land Use and Biological Resources
The Hanford Site covers 145,000 ha (358,000 ac). Approximately 6 percent of the site has been disturbed and actively used (Cushing 1995). An assessment of future land uses at the Hanford Site was conducted as part of the scoping for the Hanford Remedial Action EIS and was published as the Final Report of the Hanford Future Site Uses Working Group (HFSUWG 1992). The Central Plateau of the Hanford Site, which encompasses the 200 East and 200 West Areas, is suggested for waste storage and disposal in support of Site cleanup. The area identified in the Central Plateau for cleanup consists of a buffer zone and an exclusive waste management use area.
Table 5.13.1 Cumulative Impacts of Other Projects and TWRS Alternatives
According to the report of the Hanford Future Site Uses Working Group, all future waste from cleanup activities would be placed in the exclusive waste management use area. The buffer zone is to reduce risks that could result from waste management in the exclusive use area. The report of the Hanford Future Site Uses Working Group does not constitute official DOE policy or guidance; however, DOE initiated the study as a part of the scoping for the Hanford Remediation Action EIS to help establish cleanup levels.
A comprehensive land-use plan is being coordinated with the Hanford Remedial Action EIS to further define the preferred alternative and is expected to be finalized in 1996. Therefore, pending availability of the plan, the Final Report of the Hanford Future Site Uses Working Group will be used as the baseline for purposes of analysis in the TWRS EIS.
The proposed Central Plateau exclusive waste management use area would consist of approximately 11,700 ha (28,800 ac), including about 6,700 ha (16,600 ac) for the buffer zone and about 4,900 ha (12,200 ac) for the exclusive waste management use area. About 2,300 ha (5,800 ac) of the proposed 4,900 ha (12,200 ac) exclusive waste management use area is relatively undisturbed land, which represents the maximum area of potential impact for the TWRS alternatives and the other proposed actions described in this section.
Virtually all proposed TWRS activities under the alternatives in this EIS would occur within the Central Plateau's exclusive waste management area or at two potential borrow sites to the west of the Central Plateau. All TWRS sites would impact some shrub-steppe habitat areas, some of which are currently disturbed. There are approximately 8,500 ha (21,000 ac) of shrub-steppe habitat on the Central Plateau. This area constitutes approximately 15 percent of the total remaining Hanford Site shrub-steppe habitat. Activities under all alternatives would occur largely in areas that are currently partially disturbed, except at the two potential borrow sites, where activities would occur in currently undisturbed areas. A third potential borrow site is located on partly disturbed land between the 200 East and West Areas.
Other major projects that would be substantial contributors to cumulative land use and habitat impacts on the Central Plateau include the Hanford Remediation Program, the Environmental Restoration Disposal Facility, and the replacement cross-site transfer system. Estimates for the Hanford Remedial Action Program indicate that about 2,150 ha (5,300 ac), including about 480 ha (1,200 ac) of shrub-steppe habitat, could be disturbed by the highest impact alternatives (Jacobs 1996). Much of the waste to be generated by the Hanford Remedial Action Program would be disposed of in the Environmental Restoration Disposal Facility. Remedial action waste would result from soil and groundwater cleanup, decommissioning and decontamination of structures, and closing treatment, storage, and disposal facilities. The Environmental Restoration Disposal Facility site would cover 495 ha (1,240 ac) on the Central Plateau. In addition, approximately 55 ha (135 ac) of habitat impacts would occur as a result of borrow site activities and 40 ha (100 ac) for a rail line right of way (DOE 1994h). The replacement cross-site transfer system (addressed in the Safe Interim Storage Record of Decision [60 FR 61687]) would remove 9 ha (22 ac) of shrub-steppe habitat, with a total land commitment of 30 ha (74 ac). Approximately 6 ha (15 ac) on the Central Plateau would be disturbed to accommodate disposal of waste from decommissioning the surplus reactors. The preferred alternative for the K Basins spent nuclear fuel could disturb an additional 3.5 ha (9 ac), all of which could be shrub-steppe habitat (DOE 1995j). Regionalized or centralized alternatives under the Waste Management Programmatic EIS would use an additional 72 ha (179 ac) of Hanford Site land.
The TWRS alternative with the greatest land-use impact would be the Phased Implementation alternative, which would impact about 6 percent (269 ha [664 ac]) of the exclusive waste management use area. While TWRS impacts to land use and biological resources may not by themselves be substantial, fragmentation of the Central Plateau's habitats by TWRS alternatives, other waste management actions, and remedial actions could have a cumulative impact greater than the sum of the individual impacts. Cumulative land-use impacts for the TWRS EIS Phased Implementation alternative and other major activities on the Central Plateau are shown in Table 5.13.2.
Radiation Dose and Health Effects
The cumulative population dose due to past Hanford Site operations from startup in 1944 through 1994 has been estimated to be 100,000 person-rem (estimated to one significant figure). Using the conversion factor of 2,000 person-rem per latent cancer fatality, the number of inferred cumulative latent cancer fatalities since startup would total about 50. In the same 50 years since startup, the population of interest (assuming a constant population of 380,000 and an average individual dose from naturally-occurring radiation of 0.3 rem per year) would have received about 5,000,000 person-rem from naturally-occurring radiation sources (natural radiation), which would result in about 2,500 latent cancer fatalities. In the same 50 years, about 27,000 cancer fatalities from all causes would have been expected in that population (DOE 1995j).
Table 5.13.2 Cumulative Land-Use and Habitat Impacts
The TWRS preferred tank waste alternative is the Phased Implementation alternative, which would take about 27 years to complete. The cumulative offsite population dose from this TWRS alternative would be about 388 person-rem, which infers that about 0.2 latent cancer fatalities would result. Other planned activities that could take place in that same 27-year time period include managing spent nuclear fuel stored at the K Basins, stabilization activities at the Plutonium Finishing Plant, and programmatic waste management actions. The spent nuclear fuel management preferred alternative was identified as the Drying/Passivation with Dry Storage alternative, which would take about two years to complete (DOE 1995j). Cumulative population dose from implementing the preferred alternative would be about 2 person-rem, which infers that no latent cancer fatalities would result. Cumulative population dose from the Plutonium Finishing Plant stabilization and removal activities would be approximately 14 person-rem (DOE 1996b). No latent cancer fatalities would be expected to result from that dose. The maximum cumulative population dose in the Hanford Site region from programmatic waste management alternatives would be approximately 220 person-rem (DOE 1995m). No latent cancer fatalities would be expected to result from that dose. Continued operations of the Washington Public Power Supply System's Plant-2 for the next 27 years (0.7 person-rem per year) (DOE 1995j) would result in an additional cumulative population dose of about 19 person-rem, which infers that no latent cancer fatalities would result. Assuming that other Hanford Site activities would continue for the next 27 years at a level about equal to the present (0.6 person-rem per year) results in an additional cumulative population dose of about 16 person-rem, which infers that no additional latent cancer fatalities would result. Thus, the long-term cumulative total population dose from the reasonably foreseeable activities on the Hanford Site would be about 659 person-rem. Less than one latent cancer fatality would be expected to result from that dose.
For perspective, over the next 27 years the population (380,000 people) would have received about 2,700,000 person-rem from natural background radiation. That dose would result in about 1,350 latent cancer fatalities. In the same 27 years, about 14,000 cancer fatalities from all causes would be expected among the population in the region of analysis (within 80 km [50 mi]). The long-term cumulative population doses and health effects are presented in Table 5.13.3.
Table 5.13.3 Cumulative Radiation Population Dose and Health Effects 1
The maximally-exposed individuals would receive a cumulative annual average dose of about 0.7 mrem/yr, less than 1 percent of the 100 mrem/yr offsite dose limit (DOE 1996b).
Air Quality
Air emissions from constructing and operating facilities under the TWRS alternatives would overlap with those from ongoing Site operations and other activities on the Central Plateau including Environmental Restoration Disposal Facility operations and some Hanford Remedial Action program activities. These activities would result in cumulative air emissions.
The principal air quality impacts associated with the Environmental Restoration Disposal Facility would be from excavating disposal trenches, vehicle emissions, and fugitive dust from placing two truck loads of waste and clean fill in the trenches. The Environmental Restoration Disposal Facility would use appropriate dust suppression techniques to comply with air quality standards. Air quality impacts from Hanford Remedial Action program activities would be from excavating waste sites and transporting waste to the disposal facility.
Operating powerhouses on the Hanford Site are the primary source of criteria pollutants (particulates, nitrogen oxides, sulfur oxides, and carbon monoxide) in the Hanford Site baseline. The baseline criteria pollutant concentrations are available from estimates derived by modeling the Hanford Site operational emissions (PNL 1995). Table 5.13.4 presents the modeled baseline results along with the TWRS, Environmental Restoration Disposal Facility, and the Hanford Remedial Action program criteria pollutant impacts. The TWRS impacts are not for a single alternative but rather are the maximum values selected from among all the TWRS alternatives.
Table 5.13.4 Cumulative Air Quality Impacts
Groundwater Quality
Cumulative groundwater impacts need to be examined in the context of existing sources of contamination in the soil, vadose zone, and groundwater. The following contaminants were consistently detectable in soil on the Hanford Site: cobalt-60, strontium-90, cesium-137, plutonium-239, plutonium-240, and uranium. Soil concentrations for these radionuclides were higher near and within the Hanford Site boundaries compared to offsite concentrations (PNL 1993a). Contaminants in the vadose zone in the 200 Areas are primarily associated with past waste disposal practices using engineered structures such as cribs, drains, septic tanks and associated drain fields, and reverse wells (wells that do not penetrate to groundwater); percolation from ponds, ditches, and trenches such as B Pond and U Pond; solid waste burial in backfilled trenches; and unplanned releases such as leaks from SSTs. Contaminants include both radioactive materials (transuranic isotopes, uranium, and fission products) and nonradioactive materials (metals, volatile organics, semivolatile organics, and inorganics). In addition, the US Ecology Low-Level Radioactive Waste Disposal Facility located southwest of the 200 East Area is estimated to contain about 2.2 million curies of radioactive waste in backfilled trenches (Ledoux 1995). Reasonably foreseeable additions to contaminants in the vadose zone include future waste disposal at the 200 Area and US Ecology solid waste burial grounds and the placement of remediation waste in the Environmental Restoration Disposal Facility.
Groundwater beneath the 200 Areas and in plumes leading from the 200 Areas toward the Columbia River is contaminated with hazardous chemicals and radionuclides from past liquid disposal practices at levels that would exceed Federal drinking water standards if the groundwater was a source of drinking water as defined in the standards . Hazardous chemical contaminants present at levels that exceed drinking water standards include nitrates, cyanide, fluoride, chromium, carbon tetrachloride, trichloroethylene, and tetrachloroethylene. Radiological contaminants include iodine-129, tritium, cesium, plutonium, and strontium. Iodine-129 is present in the groundwater beneath the 200 Areas at levels that exceed standards up to 20 times. Other groundwater plumes from the 200 Areas tend to have lower levels than the iodine-129 levels; however, many of these contaminants would exceed drinking water standards if they were applicable .
Post-remediation health risks to the public from TWRS alternatives would result from contaminants in the groundwater. The first arrival of any contaminant at the interface between the vadose zone and groundwater would occur at times varying between 140 and 250 years following remediation for impacts associated with the No Action and Long-Term Management tank waste alternatives. The tank inventory would be released faster for these alternatives than for any of the other alternatives because it was assumed that there would be no engineered barriers to reduce infiltration or any attempt to remove or stabilize the tank waste. The first arrival time for contaminants from the other alternatives would occur about 2,000 years in the future and the peak concentrations would occur about 5,000 years in the future.
Cumulative radionuclide concentrations that could occur in the groundwater from a potential combination of contamination from past disposal practices, currently anticipated future waste disposal, and the contamination from the TWRS alternatives are discussed in Volume Four, Section F.4.5. Peak groundwater concentrations from the various potential sources could occur at different times and different locations. However, to maximize the potential cumulative impacts, the peak concentrations of the past and reasonably foreseeable future sources were assumed to combine with the peak concentrations from the TWRS alternatives. This resulted in a conservative bounding of the maximum potential cumulative groundwater impact for each TWRS alternative. A more detailed modeling of the potential cumulative impacts will be done in a future Hanford Site EIS. The results of the future analysis would probably indicate lower cumulative groundwater impacts than presented in this bounding analysis.
The highest cumulative groundwater concentrations occur for the No Action and Long-Term Management tank waste alternatives and the tank waste would be the dominant contributor to the predicted cumulative concentrations. The other alternatives would result in much lower cumulative radionuclides concentrations in the groundwater, and the dominant contributorswould be contamination from past disposal practices and tank leaks . The radiation dose and risk to the potential future user of the contaminated groundwater, the time at which it could occur, and the percent attributable to TWRS waste are presented in Table 5.13.5 for each alternative. The table is based on a hypothetical onsite farmer who is assumed to use the groundwater at the maximum cumulative point concentration for each alternative. The groundwater was assumed to be used for all purposes including drinking, washing, and gardening for 30 years. Future solid waste disposal at the 200 West Area solid waste burial ground and the Environmental Restoration Disposal Facility collectively would contribute about 5 rem of the hypothetical 30-year resident farmer doses presented. Less than 10 mrem of the hypothetical 30-year resident farmer dose was attributed to past and future solid waste disposal at the US Ecology solid waste burial ground.
Table 5.13.5 Cumulative Groundwater Radiation Dose and Health Effects
Cumulative radiation doses ranged from about 790 rem for the No Action (Tank Waste) alternative to about 51 rem for the ex situ alternatives. The in situ alternatives were somewhat higher than the ex situ alternatives. The groundwater impacts of the Ex Situ/In Situ Combination 1 and 2 alternatives were for the specific combinations of waste retrieval for disposal and waste disposed of in place chosen for detailed analysis. Other variations of the Ex Situ/In Situ Combination 1 and 2 alternatives could present higher or lower groundwater impacts ranging between the ex situ alternatives ( 51 rem ) and the In Situ Fill and Cap alternative ( 68 rem ). The cumulative radiation dose under the Long-Term Management alternative after administrative control was assumed to end would be about 480 rem. At 10,000 years after disposal, the potential dose from the cumulative contamination in groundwater would be about 3 rem for any alternative except for In Situ Fill and Cap, which would be about 6 rem.
Nitrate concentrations measured in the 200 Area wells in 1994 ranged up to 1,700 mg/L. In addition, nitrate remains in the vadose zone from past disposal practices and will migrate to groundwater over the next several decades. Because of its relatively high mobility, most of the nitrate associated with past liquid disposal practices has probably already entered the groundwater and the maximum concentrations from past disposal practices would have already occurred. This is supported by the fact that nitrate concentrations in the 200 Area groundwater are generally decreasing. Further, it is assumed that the groundwater will transport much of the nitrate from past disposal practices from the 200 Area before arrival of any potential contamination from the TWRS alternatives. Therefore, the nitrate from past disposal practices and from the TWRS alternatives was not expected to combine to give higher concentrations but will extend the time period over which nitrate will be present in the groundwater at potentially high concentrations. Detailed discussion of nitrate contamination from TWRS alternatives is presented in Section 5.2.1.
The maximum nitrate concentrations and the time at which they will be present in the groundwater are presented in Table 5.13.6. The potential nitrate concentrations ranged from 6,600 mg/L for the No Action (Tank Waste) alternative to about 5 mg/L for the Phased Implementation alternative. All other ex situ alternatives would also result in nitrate contamination of the groundwater of about 5 mg/L. The in situ alternatives ranged from about 130 mg/L for the In Situ Fill and Cap alternative to about 0 mg/L for the In Situ Vitrification alternative. Nitrate concentration under the Long-Term Management alternative after administrative control was assumed to end would be about 1,050 mg/L.
Socioeconomics
The socioeconomic impact analysis described in Section 5.6 assessed the impacts of the TWRS EIS alternatives on the Tri-Cities area. The socioeconomic impacts of the TWRS alternatives were measured against a baseline projection of economic activity and population growth that assumed the successful completion of scheduled milestones for Hanford Site cleanup and environmental restoration under the Tri-Party Agreement. Cumulative impacts from TWRS alternatives were analyzed against the baseline of steadily declining Hanford Site employment, which was projected to drop from approximately 15,000 in 1997 to approximately 5,600 in 2040. In that same time frame, nonfarm employment in the Tri-Cities area was projected to increase from approximately 68,000 to 89,000. The peak year impact of each TWRS EIS alternative on Hanford Site employment, Tri-Cities nonfarm employment, and housing prices is presented in Table 5.13.7.
Table 5.13.6 Cumulative Groundwater Nitrate Concentrations
If decisions were made that led to constructing and operating facilities at the Hanford Site not currently foreseen and reflected in the baseline, there would be additional employment, transportation, and infrastructure impacts to the Tri-Cities area.
|
NEWSLETTER
|
| Join the GlobalSecurity.org mailing list |
|
|
|
