SOW_BlackSpringsSDVCleanup.pdf

Scope of Work

Sheep Dip Vat (SDV) Site Removal

Black Springs, Navajo Nation Superfund Site SDV019

Navajo Nation, Naschitti, New Mexico

INTRODUCTION

The Bureau of Indian Affairs (BIA) Navajo Regional Office (NRO) Branch of Environmental Management

(BEM) is seeking an Environmental contractor to conduct the removal of the former Black Springs Navajo Nation

Superfund Site SDV019, Sheep Dip Vat (SDV). The SDV is located off NM Highway 491, west of the Naschitti, NM community. The site is located on the Navajo Indian Reservation with coordinates of 108.8310698°W, 36.0296005°N (WGS 1984). The Black Springs SDV is assessable using a dirt road driving off State Highway

491 (Figure 1) The surrounding land use of the area is undeveloped and which is primarily used for grazing of livestock and wildlife.

BEM is conducting the voluntary cleanup for the Sheep Dip Vat (SDV) site under the authority of Comprehensive, Environmental Response Compensation and Liability Act of 1980 (CERCLA) which will require the complete removal of SDV structures and contaminated soil at the site. Previous contactors have completed the Preliminary

Assessment in FY 2016 and site characterization for toxaphene in FY2019 for the Black Springs SDV. These reports are available at the BEM office. The site characterization effort was to identify contamination of organochlorine pesticide, toxaphene.

The primary soil screening value for toxaphene is set for 0.49 parts per million (ppm) protective of human health and the environmental as required by the Navajo Nation Environmental Protection Agency (NNEPA) Superfund

Program. BIA under the voluntary cleanup includes the permanent removal of SDV structures and associated contaminated soil as regulated by the CERCLA (40 CFR 300).

BACKGROUND

The Black Springs SDV site description consists of partially dismantled pre and post dip corrals, a concrete dip vat with concrete entry and exit pads, the dismantled heating units and drainage system that were used to discharge spent toxaphene solutions into unlined disposal area. The ground surface is relatively flat and consists of dirt, natural desert vegetation and weeds; underlain by flood-plain alluvium, consisting of gray to lavender-tan moderately well-sorted fine sandy and clayey silt and fine sand.

The former SDV was used to apply toxaphene as a pesticide to the livestock, primarily sheep, to eradicate skin conditions and ticks. The dip vat is a concrete lined subgrade trough, 4 feet (ft.) wide, 5 ft deep, and 44 ft in length. At the entrance to the dip vat is 10 ft long by 20 ft wide concrete pad that funnel livestock (sheep) into the trough (vat). Sheep were herded into the dip vat using a chute, where they swam through the pesticide solution and exited out of the trough on the other end. The SDV water source was by way of underground piping and plumbed through an aboveground boiler which was also used to warm the water. The pesticide solution was discharged to the unlined pits through valve box, which was connected to the drain center near the bottom of the trough.

The previous contractor collected a total of eight (8) surface water with one (1) background sample and a total of twenty-eight (28) soil samples with three (3) duplicates and one (1) background sample. All surface water samples were analyzed by EPA Method 8081 and all soil samples were analyzed by EPA Method 8081A. A background surface water sample was collected approximately 2,000 ft east of the SDV. The background surface water sample was collected from a covered above ground well. The water level within the well was near the top of the well. The surface water sample was collected directly from the well in laboratory supplied 4 oz glass jar.

The background surface soil sample was collected approximately 200 ft upgradient of the SDV. The background surface soil sample was collected by removing surface vegetation to expose the soil and then collecting a representative sample from 12 inches bgs using stainless steel trowel.

Laboratory analytical results indicated detections of toxaphene in fourteen 14 soil samples with 14 samples having concentrations exceeding the Regional Screening Level (RSL) of 0.49 milligrams per kilogram (mg/kg). Figure

3 of the Final Report shows the sample locations and the locations with RSL exceedances. Toxaphene detections ranged in concentration from 0.809 mg/kg to 22.6 mg/kg. Soil sample detections were primarily located proximal to the former SDV exit pad and drainage ditch. Toxaphene was not detected in any of the eight surface water samples. The complete laboratory analytical reports are provided in Appendix A of the Final Report.

PERIOD OF PERFORMANCE: The period of performance will be 120 calendar days from Notice to

Proceed.

TASK 1: Pre-Submittals

A. Prepare a detailed Work Plan and the Project Schedule for BIA’s review and approval prior to commencement of work. The plan should document the proposed work, soil sampling, and excavation and off-disposal activities.

The work plan shall include traffic routes, dust control, communication plan for the general public.

B. Prepare a Health and Safety Plan (HASP). The contractor shall prepare a site-specific HASP in accordance with 29 CFR 1910.120 to allow for the protection of workers, employers, and the general public. The HASP will contain certifications/licensures or workers and describe the use of all and appropriate PPE. Task-specific physical hazards and other hazards that may be encountered during work at the sites. Known and potentially occurring environmental hazards are exposure to petroleum hydrocarbons, potentially explosive atmosphere conditions, and tripping/falling hazards, presence of heavy equipment, utility lines, biological hazards, chemical hazards, and venomous insects, snakes/spiders.

C. Grid soil sampling plan to delineate contamination that exceed the Regional Screening Levels (RSL) at the investigated area near the exit and entrance pads of the SDV.

D. Notification to NNEPA Superfund Program, Window Rock, Arizona on the proposed work by preparing a letter on behalf of BIA to include proposed work.

E. Name of the accredited and certified laboratory to analyze the samples using EPA method 8081A.

TASK 2: Coordination/Sampling/Analyses

A. Coordination of meetings with the Regulatory Agencies on the Voluntary Compliance event to receive input and comment on the proposed work plan and work schedule for the Black Spring SDV. Contractor shall be available to participate in meetings and present findings of the soil sampling and proposed work.

B. Confirmation of the extent of contamination must be verified by laboratory analyses of soils for each and analyzed for organochlorine pesticides analysis by EPA Method 8081A.

C. The contractor shall prepare map, grid and table showing the Global Positioning System (GPS) the location of the sampling and results of the sampling area. Contractor shall provide where the SDV is located and associated developments to document where the items were located prior to removal.

D. Other sampling requirements maybe identified following consultation with NNEPA and USEPA. The sampling protocols will be identified and bid submittal by the contractor will be sent to the contracting officer for inclusion in the Statement of work (SOW) without further advertisement.

TASK 3: Removal Actions

A. All sheep dip vat structures onsite shall be removed. This includes any wooden posts, concrete pads, and associated development structures such as piping shall be removed by the contractor.

B. All estimated cubic yards of contaminated soils shall be removed by contractor and backfilled with clean soils.

TASK 4: Soil Sampling- SDV perimeter with RSL exceedance.

The soil sampling results showed exceedances located on the outer boundaries of the grid, further sampling along the respective grid boundaries is required, to ensure all the contamination is removed from the site. It is recommended the current grid be extended by two 10 ft by 10 ft rows for an extension of 20 ft beyond the current perimeters at SB-8 and SB-37 as shown in Figure 4. The soil boring placement recommended is to conduct the soil sampling as previously completed by the former contractor. By placement of one (1) boring on each of the corners and in center of each grid of the extended investigation area. Soil samples will be collected at depths of

0-0.5 ft, 0.5-1 ft, 1-3 ft, and 3-5 ft, for total of four (4) samples per boring.

It is assumed that the contamination in excess of the RSL extend an additional 10 ft outside the investigation area near SB-8 and SB37. Based on this assumption, approximately 145 cubic yards of soils shall be excavated. Based on the soil data, the maximum depth of the excavation is assumed to be 1 ft bgs. Figure 4 shows the proposed excavation required to remove all toxaphene impacted soil in excess of the RSL. If confirmation samples contain toxaphene in exceedance of the RSL, an additional round of excavation

Soil samples taken at the extended area shall be submitted to accredited laboratory to be analyzed for toxaphene using EPA Method 8081A. The complete analytical data reports from the laboratory shall be provided to BIA and show the extent of toxaphene contamination at the perimeter areas as recommended. If the soil is contaminated with toxaphene the soil shall require removal. Soil samples taken at the extended area shall be submitted to accredited laboratory to be analyzed for toxaphene using EPA Method 8081A. The complete analytical data reports from the laboratory shall be provided to BIA before excavation occurs to show the extent of toxaphene contamination beyond the current perimeter.

TASK 5: Excavation

The remedial action for the Black Springs SDV site is based on the data obtained from the site investigation to conduct the excavation and off-site disposal of the contaminated soil/concrete to a Subtitle D landfill. The objective of the SOW is to remove the risk of exposure of contaminated soils at the site.

A. The remedial action shall require the contractor to excavate approximately 143 cubic yards of toxaphene impacted soils and 240 tons of toxaphene–impacted concrete. The removal of contaminated soil will also include the perimeter of areas if the samples show exceedance of the RSL.

B. The contractor shall provide the amount of contaminated soils that shall be removed beyond the perimeter of the SDV site based on soil sampling results. Should additional excavation is required for the areas that are sampled, contractor shall provide the cubic yards to be removed and costs before excavation is conducted.

C. The excavated areas will be backfilled with clean soil. Contractor shall fill all voids and the excavated area with clean fill and compact the area to 90% proctor density; grade and contour the area to prevent ponding or subsidence and meet the existing grad elevations contours. Care shall be taken by the contractor conducting the backfilling of the excavated area. Backfill sources shall be provided to BIA by the contractor.

D. Due to homes nearby contractors shall wet down the areas to minimize dust control during the excavation process, as there are nearby residents near the SDV site. A Project manager shall be onsite for the entire duration to conduct, assist, to oversee the project and assure the safety of the technicians conducting the work.

A. Prepare a detailed Work Plan and the Project Schedule for BIA’s review and approval prior to commencement of work. The plan should document the backfill process, the inspections for the monitoring wells, bioremediation injection system and the estimate of the visible asbestos waste length and depth of the wall.

The work plan shall include traffic routes, dust control, communication plan with employees and the general public, backfill sources, approach to inspections of the monitoring wells and injection piping anticipated for replacement. Costs shall be provided to BIA before replacement occurs.

B. Prepare a Health and Safety Plan (HASP). The contractor shall prepare a site-specific HASP in accordance with 29 CFR 1910.120 to allow for the protection of workers, employers, and the general public. The HASP will contain certifications/licensures or workers and describe the use of all and appropriate PPE. Task-specific physical hazards and other hazards that may be encountered during work at the sites. Known and potentially occurring environmental hazards are exposure to petroleum hydrocarbons, potentially explosive atmosphere conditions, and tripping/falling hazards, presence of heavy equipment, utility lines, biological hazards, chemical hazards, and venomous insects, snakes/spiders.

TASK 6: Disposal

Contractor shall provide traffic plan to ship out the contaminated soils and concrete. The removal of all concrete dip vat, entrance, and exit pads and associated piping/concrete structures shall be excavated and disposed of a

Subtitle D landfill. The San Juan County Landfill in Aztec, NM is closed permitted Subtitle D Landfill that accepts non-hazardous waste construction and demolition debris. For estimating purposes, contractor will provide the name of the disposal facility for the soil and concrete to be transported.

Contractor shall assure all documentation for the disposal are maintained and if manifests are required a BIA shall sign off and shall be made record and provided in the final reports. The contractor may not sign on behalf of the

BIA.

Task 7 -Reports

The contractor will develop a draft and final Report containing

A. A description of the work performed and figures showing the sampling locations and results.

B. Maps, Tables with GPS coordinates and drawings of sampling locations shall be included. Sample log, field forms, photographic logs suitable for an explanation of findings/work will be presented in the report.

C. Full documentation shall be maintained for all field testing, results and project completions. During field situations, the contractor shall maintain a daily log and record all events relevant to a task order. Any additional sub-contractors shall do likewise. The logs will be signed and closed daily. The logs shall become the property of BIA. A copy of all bills, receipts and time sheets shall be maintained, in case there is ever a possible claim for cost recovery.

E. Draft/Final Report 10 days. The draft report documenting all activity, findings and progress soils sampling, excavation, and disposal shall be submitted to BIA for review and comment. The final report shall include all drawings, photographic logs, and borings depth.

F. When the draft is approved to finalize, the contractor shall prepare five (5) final copies and four (4) electronic copies in Microsoft Word format two read only and one writeable version marked for “BIA Use Only”. The BIA shall be the owner of all documents prepared by the contractor. The contractor shall not copyright or write protect any documents or utilize any data from the project without consent of the government.

G. Environmental Professional Certification: the report shall be stamped and certified by an environmental professional that the work was conducted in accordance with work plan and applicable environmental federal regulations.

Acceptance Requirements: The COR, in consultation with the Branch of Environmental Management (BEM) and possibly representatives of the United States Environmental Protection Agency (USEPA) and Navajo Nation

Environmental Protection Agency (NNEPA), will determine the acceptability of work performed. If, and when, any agent of the Navajo Nation communicates with the contractor, BEM CO shall be immediately informed. The contractor may not communicate project work on behalf of the federal government.

INSTRUCTIONS, CONDITIONS AND NOTICES TO CONTRACTORS

Special conditions

The contractor shall adhere to all applicable federal and tribal laws and regulations and payment of tribal taxes.

The contractor shall be required to furnish electrical power and procure water to perform the remedial actions for toxaphene cleanup. All testing equipment or solid waste shall be removed on daily basis from the site.

Contractor shall not donate concrete or any materials to the local public due to potential liability issues for BIA and the contractor.

All contact with the general public, private and regulatory community shall be made through BIA, BEM COR.

No information may be released without written consent of the BIA Navajo Region BEM.