Environmental Remediation of 300-FF-1 Operable Unit: Soil and Groundwater Contamination, Lecture notes of Remedies

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EPA Superfund

Record of Decision:

PB96-

EPA/ROD/Rl0-96/

August 1996

Hanford 300 Area (USDOE), 300-FF-1 and

300-FF-5 Operable Units, Benton County, WA

7/17//

DECLARATION OF THE RECORD OF DECISION

SITE NAME AND LOCATION

USDOE Hanford 300 Area 300-FF-1 and 300-FF-5 Operable Units Hanford Site Benton County, Washington

STATEMENT OF BASIS AND PURPOSE

This decision document presents the selected final remedial and interim remedial actions for portions of the USDOE Hanford 300 Area, Hanford Site, Benton County, Washington, which

were chosen in accordance with the Comprehensive Environmental Response, Compensation,

and Liability Ac£ of I 980 (CERCLA), as amended by the Superfund Amendmenrs and

Reauthorization Ac£ of 1986 (SARA), and to the extent practicable, the Narional Oil and

Hazardous Substances Pollution Conringency Plan (NCP). This decision is based on the

administrative record for this site. 1

The Washington State Department of Ecology (Ecology) concurs with the selected remedies.

ASSESSMENT OF THE SITE

Actual or threatened releases of hazardous substances from this site, if not addressed by implementing the response actions selected in this Record of Decision (ROD), may present an imminent and substantial endangerment to public health, welfare, or the environment.

DESCRIPTION OF THE SELECTED REMEDIES

This ROD addresses actual or threatened releases from the wastes sites in the 300-FF- Operable Unit and the groundwater in the 300-FF-5 Operable Unit. 300-FF-l and 300-FF- are two of the three operable units that comprise the USDOE Hanford 300 Area National Priorities List site. The third operable unit (300-FF-2) consists of the remaining waste sites in the 300 Area NPL site and any associated groundwater that is not part of 300-FF-5. Actual or threatened releases from the waste sites and the groundwater in 300-FF-2 will be addressed in a future ROD. The major components of the selected final remedy for 300-FF- l include:

• Removal of contaminated soil and debris;
  • Disposal of contaminated material at the Environmental Restoration Disposal Facility;
  • Recontouring and backfilling of waste sites, followed by revegetation;

Signature sheet for the Record of Decision for the USDOE Hanford 300-FF-1 and 300-FF-

Operable Units Remedial Actions between Lhe United Stales Department of Energy and the

Depart1_nenL of Ecology.

D. Wagoner ager, Richland Ope tions United States Department of Energy

2/;1 /u

Date

Ill

Signature sheet for the Record of Decision for the USDOE Hanford 300-FF-1 and 300-FF-

Operable Units Remedial Actions between the United States Department of Energy and the

Department of Ecology.

17 f,b c,f s}iuck Clarke / 1 V ~~gional Administrator, Region 10

United States Environmental Protection Agency

lV

TABLE OF CONTENTS.

• DECISION SUMMARY DECLARATION OF THE RECORD OF DECISION i - SITE NAME, LOCATION, AND DESCRIPTION - SITE HISTORY AND ENFORCEMENT ACTIVITIES - HIGHLIGHTS OF COMMUNITY PARTICIPATION - SCOPE AND ROLE OF RESPONSE ACTION WITHIN SITE STRATEGY - SUMMARY OF SITE CHARACTERISTICS - SUMMARY OF SITE RISKS - REMEDIAL ACTION OBJECTIVES - DESCRIPTION OF ALTERNATIVES - SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES - SELECTED REMEDIES
  • STATUTORY DETERMINATIONS
  • DOCUMENTATION OF SIGNIFICANT CHANGES
• RESPONSIVENESS SUMMARY 1 • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • •

DECISION SU1\1MARY

The U.S. Department of Energy's Hanford Site is a 560-square-mile federal facility located in southeastern Washington along the Colun1bia River (see Figure 1). The region includes the incorporated cities of Richland, Pasco, and Kennewick (Tri-Cities), as well as surrounding communities in Benton, Franklin, and Grant counties. The Hanford Site was established during World War II, as part of the Manhattan Project, to produce plutonium for nuclear weapons. Hanford Site operations began in 1943.

The 300 Area, which encompasses approximately 1.35 sq km (0.52 sq mi), is adjacent to the Columbia River and approximately 1.6 km (1 mi) north of the Richland city limits. The 300 Area is generally level, with a steep embankment dropping to the river. The waste sites in 300-FF-1 are not near any wetlands and are not within the 100-year floodplain. The 300 Area began as a fuels fabrication complex in 1943. Most of the facilities in the area were involved in the fabrication of nuclear reactor fuel elements. In addition to the fuel manufacturing proc- esses, technical support, service support, and research and development related to fuels fabrication also occurred within the 300 Area. In the early 1950' s, the Hanford Laboratories were constructed for research and davelopment. As the Hanford Site production reactors were shut down, fuel fabrication in the 300 Area ceased. Research and development activities have expanded over the years. The 300 Area contains a number of support facilities, including a powerhouse for process steam production; a water intake and treatment system for potable and process water; and other facilities necessary for research and development, environmental restoration, decontamination, and decommissioning.

II. SITE HISTORY AND ENFORCEMENT ACTIVITIES

The Hanford Site was listed on the National Priorities List (NPL) in November 1989 under the

Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA)

as amended by the Supe,fund Amendments and Reauthorization Act of 1986 (SARA). The

Hanford Site was divided and listed as four NPL Sites: the 100 Area, the 200 Area, the 300 Area, and the 1100 Area.

In anticipation of the NPL listing, the U.S. Department of Energy (DOE), the U.S. Environmental Protection Agency (EPA), and the Washington State Department of Ecology

(Ecology) entered into the Hanford Federal Facility Agreement and Consent Order (known as

the Tri-Party Agreement) in May 1989. This agreement established a procedural framework and schedule for developing, implementing, and monitoring remedial response actions at

Hanford. The agreement also addresses Resource Conservarion and Recovery Act (RCRA)

compliance and permitting.

In 1988, the Hanford Site was scored using EPA' s Hazard Ranking System. As a result of the scoring, the Hanford Site was added to the NPL in November 1989 as four sites (the

100 Area, the 200 Area, the 300 Area, and the 1100 Area). Each of these areas was further

divided into operable units, which are groupings of individual waste units based primarily on

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operable units: 300-FF-1, 300-FF-2 and 300-FF-5 (see Figure 2). The 300-FF-l Operable

Unit addresses contaminated soils, structures, debris, and burial grounds. The 300-FF-

Operable Unit is as generally depicted in Figure 2 and includes contaminated soils, debris,

burial grounds, and groundwater. The 300-FF-5 Operable Unit is as depicted in Figure 2 and

addresses the groundwater beneath 300-FF-l and part of 300-FF-2.

The 300-FF-1 Operable Unit covers an area of approximately 47.4 ha (117 acres) and contains

many of the current and past 300 Area liquid waste disposal units. The 300-FF-1 Operable

Unit is bounded on the east side by the Columbia River and on the north, south, and west sides

by the 300-FF-2 Operable Unit.

The waste sites in 300-FF-l have been divided into two categories: process waste sites and the

burial ground. The process waste sites received primarily liquid wastes, and the burial ground

received primarily solid wastes. Table 1 provides a summary of the physical characteristics of

these sites.

300-FF-1 Process Waste Sites. The process waste sites are the South Process Pond, the

North Process Pond, the Process Trenches, the Process Trenches Spoils Pile, the Process

Sewers, the Sanitary Tile Field and other sanitary sewage waste sites, the Ash Pits, the Filter

Backwash Pond, the Retired Filter Backwash Pond (located over part of the South Process

Pond), the North Process Pond Scraping Disposal Area, the 300-3 Aluminum Hydroxide site,

and Landfills la, lb, le, and ld. Landfills la, le, and ld were originally grouped with the

Burial Grounds in the remedial investigation and feasibility study (RI/FS). After further

evaluation, however, it was determined that the remedy for the process waste units also will

apply to the landfills for the following reasons: the landfills are small in area and volume

when compared to the burial ground, Landfills lb and ld are co-located within part of the

North Process Pond Scraping Disposal Area, and Landfills la and le are near the North

Process Pond and the Columbia River.

The South Process Pond is an inactive, unlined surface impoundment in the southern

area of 300-FF-1. The South Process Pond was the first disposal facility for liquid

process wastes in the 300 Area. These liquid wastes contained uranium, copper, and

aluminum, as well as traces of other contaminants. The pond also received slurried ash

from the coal-fired power house. It was built in 1943 and was operated until 1975,

when it was replaced by the Process Trenches. This pond was originally a single large

infiltration basin with the inlet in the southwest corner. In 1948, after the North

Process Pond was constructed, the inlet was moved to the northwest corner. In 1951, a

dike was constructed across the south end of the pond to form the eastern Ash Pit and

the now-retired filter backwash pond (now called the Retired Filter Backwash Pond).

Later, dikes were added to route the flow through the pond. The inlet was in the

northwest corner, from which the wastewater flowed through three small settling basins

~

® 600- Wye Barricade r<i'&i.."'· H.J. Ashe

Legend

fx&:~ 300-FF-2 Operable Unit

-@I 300-FF-1 Operable Unit

~ 300-FF-5 Operable Unit

'xW Substation Q@y 618-

400 Area

~618- 316-

600-

Hanford Site Boundary

0 3 KILOMETERS 0 ~--=~-- 2 MILES APPROXIMATE

Figure 2. 300 Area Operable Units.

4

Benton Substation S~itch ~ v::.s:J

E960404S 8

Facility Years of Description/Designation Service/Status

Process Sewer System 1943- (within 300-FF-1) Inactive

Sanitary Sewer System Post-1954 to (Sanitary Trenches) Present Active

Ash Pits 1943-Present Active Filter Backwash Pond 1987-Present Active

Retired Filter Backwash 1975- Pond (Infiltration Basin Inactive within South Process Pond)

Table 1. 300-FF-l Waste Sites. (Sheet 2 of 3)

Waste

• Process wastewater ( cooling water and low-level radioactive liquid wastes from fuels fabrication)
• Laboratory wastes
• Chemical spills
• Sanitary sewage (^) -
• Septic tank overflow
• Cooling water
• Small quantities of photographic chemicals
• Slurried coal fly ash
• Water treatment filter backwash
• Water treatment filter backwash

Construction

24-in.-diameter vitreous clay pipe, 1 ith gasketed bell and spigot joints. On \y those portions of the process sewe located within the operable unit an addressed. 8-in. clay pipe to septic tanks and t No parallel leaching trenches, each 51l( by 12 ft wide; tanks once drained to n iw abandoned tile field. Only the port ons of the sanitary sewer located within tl 1e operable unit boundaries are addrc ;sed Two pits 15 to 20 ft deep.

Single basin 20 to 25 ft deep, with a synthetic liner which rests on a. cor crete liner/foundation; part of south process pond 1944-1951. Ash pit prior to use as filter backwash pond. Eastern pit part of south process pond 1944-1951.

Facility Years of Description/Designation Service/Status Landfill la Unknown Inactive

Landfill 1b Unknown Inactive

Landfill le Unknown Inactive

Landfill ld 1962- Inactive Burial Ground No. 4 1955- (618-4) Inactive

Table 1. 300-FF-l Waste Sites. (Sheet 3 of 3)

Waste

• Located between Burial Ground 618- and the river. Evidence suggests the area was used for burning debris. Waste types undetermined, probably from laboratories.
• Located south of Burial Ground 618- and bounded by the North Process Pond perimeter fence. General area identified as having received wastes. Quantity unknown.
• Unknown wastes. Located directly east of the northeast corner of North Process Pond. Waste was removed during the remedial investigation.
• Located north of the west end of the sanitary trenches. Used as burn pit.
• Miscellaneous uranium-contaminated materials

Construction

Several parallel trenches; precise dimensions unknown.

Undetermined.

Undetermined.

Burn pit for miscellaneous debris.

Approximately 110,000 ft^2 , depth

unknown.

Retention Basins. The trenches did not have outlets; water loss was by infiltration and

evaporation.

By the late 1980's, the process wastewater contained very little uranium. However, the

groundwater still had significantly elevated uranium concentrations. The relatively

clean process wastewater was mobilizing uranium previously deposited in the bottom of

the trenches and carrying it to the groundwater. In 1991, DOE performed an expedited

response action (ERA) under CERCLA removal authority at the Process Trenches.

The objective was to move contaminated soils from the south end of the Process

Trenches to the dry north end, thus preventing process wastewater from passing

through the contaminated soil and driving contamination to groundwater.

Approximately 10,800 m^3 (14,000 yd 3 ) was moved in the trenches. The more

contaminated materials were placed in a depression in the northwest corner of the west

trench. The less contaminated material was moved to the north end of the trenches,

graded, and covered with a plastic barrier and a layer of clean aggregate. The

contaminated sediments were left within the boundary of the Process Trenches and are

referred to as the Process Trenches Spoils Pile. In 1994, a new effluent treatment and

disposal facility was started up, eliminating discharges to the Process Trenches

completely.

The Process Sewer System transferred liquid process \vastes to the process ponds and

trenches. Only those portions of the process sewer system located within the operable

unit are included within the scope of 300-FF-1. The system is constructed of vitreous

clay pipe and the trunk sewer diameter is 61 cm (24 in.). The original process sewer

serving the South Process Pond was later modified to serve the North Process Pond.

The process sewers were further modified to serve the Process Trenches, as well as the

307 Retention Basins located in the 300-FF-2 Operable Unit. The portion of the

process sewers serving the North and South Process Ponds was reportedly abandoned in

March 1975. However, documentation of abandonment exists for only the pipe that

fed the southwest corner of the South Process Pond. The as-abandoned condition has

not been identified for the pipe that fed the northwest corner of the South Process Pond

or for the pipe to the North Process Pond.

The Sanitary Sewage Waste Sites handle sanitary sewage from the 300 Area. The

sewage travels through sanitary sewers constructed of vitreous clay pipe. The sanitary

sewers discharge to septic tanks. The septic tanks are periodically cleaned, and the

sludge is disposed of in an adjacent sludge pit. Between 1943 and 1948, the septic

tanks were connected to a tile leach field constructed of perforated clay pipe. The tile

field was replaced by the Sanitary Sewage Trenches, which are still in use. The south

sanitary sewage trench was evidently constructed prior to or during 1948. The north

sanitary sewage trench was constructed in 1952 across portions of the abandoned tile

field. This ROD addresses only those sections of the sanitary sewer located within the

300-FF-1 Operable Unit. The Sanitary Sewage Trenches will be taken out of service in

the next few months when the sanitary wastes from the 300 Area will be discharged to

the City of Richland system.

The Ash Pits received slurried fly ash, which was generated at the 300 Area

powerhouse when coal \Vas burned. Currently, the powerhouse is using No. 6 fuel oil

to two ash pits located between the South Process Pond and the 307 Trenches. The

area of the Ash Pits was originally part of the South Process Pond. Presumably, some

contaminated soil and/or sludge from pond operations remains beneath the fly ash. The

Ash Pits originally consisted of a single trench; the trench was divided into the current

configuration around 1960. The Ash Pits often filled up, so sludge was removed and

placed near the river bank or between the north and south process ponds. It is

presumed that, as time progressed, ash was allowed to accumulate at the east end of the

east pit, eventually to the point where the original extent was no longer apparent and

only a limited portion of the ash pit was actually being used.

The Filter Backwash Pond was constructed in 1987 to receive filter backwash from

the 300 Area potable water treatment plant. The backwash contains a high

concentration of alum, which settles in the pond. This facility is located directly east

of the Ash Pits, as currently configured. Prior to 1951, the area was part of the South

Process Pond. The pond has a synthetic liner which rests on a concrete

liner/foundation. After the alum has settled, the water is recycled through the water

treatment plant.

The Retired Filter Backwash Pond was constructed over a portion of the infiltration

basin of the South Process Pond. When the South Process Pond was retired in 1975,

the infiltration basin was used for disposal of filter backwash. The infiltration basin

operated until 1987.

The 300-3 Aluminum Hydroxide Site was identified during installation of a sump pit

for the 300 Area Treated Effluent Disposal Facility. The site consists of several

horizontal 0.3- to 0.45-m- (1- to 1.5-ft) diameter cedar logs forming a vertical wall

approximately 10 ft high running in a north/south direction. The top part of the wall

slopes downward to the west and the bottom part is vertical. The structure appears to

be resting on a concrete slab at a depth of approximately 3 to 4.5 m (10 to 15 ft). A

white chalky material was found during the excavation. The material was determined

to be aluminum hydroxide; Toxic Characteristic Leaching Procedure analysis indicated

that the material was not a dangerous waste. The constituents in the material were all

below health-based concentrations and the material was determined to be nonhazardous

and was left in place at the site.

Landfills la, lb, le, and ld were identified during a review of aerial photographs.

Radioactive contamination and debris were found on the surface of Landfill la. The

materials appeared to be similar to laboratory wastes. Small amounts of what appeared

to be "yellowcake" (uranium oxide concentrate) were also found. Landfills lb and le

were identified as disturbed or graded areas north of the North Process Pond and near

the Columbia River. Landfill lei was identified as a relatively large burn pit.

Historical records indicate that, although some incidental radioactive materials may

ADMINISTRATIVE RECORD (Contains all project documents.)

lJ- .S. f)0n~rtn1Pnt.-L nf f:110r:rv~.

Richland Field Office

Administrative Record Center

2440 Stevens Center Place

Richland, Washington 99352

EPA Region 10

Superfund Record Center

1200 Sixth Avenue

Park Place Building, 7th Floor

Seattle, Washington 98101

Washington State Department of Ecology

Administrative Record

300 Desmond Drive

Lacey, Washington 98503-

INFORMATION REPOSITORIES (Contain limited documentation.)

University of Washington

Suzzallo Library

Government Publications Room

Mail Stop FM-

Seattle, Washington 98195

Gonzaga University

Foley Center

E. 502 Boone

Spokane, Washington 99258

Portland State University

Branford Price Millar Library

Science and Engineering Floor

SW Harrison and Park

P.O. Box 1151

Portland, Oregon 97207

DOE Richland Public Reading Room

Washington State University, Tri-Cities

100 Sprout Road, Room 130

Richland, Washington 99352

Notices of the public comment period and availability of documents for review were published in the Seattle PI/Times, the Spokesman Review-Chronicle, the Tri-City Herald, and the Ctet!,Ufliun 011 .December 3, iSSj aw.i again 011 De-.;cmbc1 ..;., :;;.:;. ~lie llu~icc: abu i ..tu throughout the week of December 3 in the various papers published by the Hood River News. Additionally, a 2-page focus sheet that summarized the Proposed Plan was mailed on November 30, 1995 to an "interested in Hanford" mailing list of about 4,700 people. That mailing list included the members of the Hanford Advisory Board (a citizen/stakeholder cleanup advisory board), Native American Tribes with reserved treaty rights to Hanford- related resources, and natural resource trustees. Focus sheets and proposed plans were mailed to a number of individuals in response to requests during the comment period. The extended comment period was announced in the Tri-City Herald on January 14, 1996. The proposed plan and focus sheet identified that a public meeting would be held upon request. No public meeting was requested. A response to the comments received during the public comment period is included in the Responsiveness Summary, which is Appendix A of this ROD. Briefings and discussions were held with the Environmental Restoration Subcommittee of the Hanford Advisory Board on December 6, 1995 and on January 25, 1996.

This decision document presents the selected remedial actions for the 300-FF-1 and 300-FF- Operable Units at the Hanford Site in Richland, Washington. The selected remedies are chosen in accordance with CERCLA: as amended by SARA, and to the extent practicable, the National Contingency Plan (NCP). The decision for these operable units is based on the Administrative Record.

IV. SCOPE AND ROLE OF RESPONSE ACTION WITHIN SITE STRATEGY

The cleanup actions described in this ROD address known current and potential risks to human health and the environment from 300-FF-l. The interim actions for 300-FF-5 described in this ROD address known current and potential risks to human health and the environment from the uranium, trichloroethene, and 1,2-Dichloroethene in the groundwater. This ROD does not address other contaminants (e.g., tritium) that may be present in 300-FF-5 which are reserved for future actions. These actions are enhanced by the 1991 ERA and the elimination of liquid waste discharges in the 300 Area. The remedial action at Burial Ground 618-4 will provide information helpful in selecting remedial actions at the burial grounds in 300-FF-2. This ROD addresses the contaminated soil and debris in 300-FF-1 and the contaminated groundwater in 300-FF-5 described above. This ROD also requires the disposal of excavated contaminated materials from the 300 Area Process Trenches. The Process Trenches are subject to closure requirements under RCRA. The closure plan and the specific permit conditions will be part of the Hanford Site RCRA permit. Actual or threatened releases from the waste sites and the groundwater in 300-FF-2, and a final remedial decision for 300-FF-5, will be the subject of future proposed plans and RODs.

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