SOW_SebaDalkaiGroundwater.pdf

Groundwater Sampling and

Decommissioning of 7 Monitoring Wells Seba Dalkai Boarding School, Seba Dalkai, Arizona

Introduction:

The Scope of Work (SOW) requires the services of environmental professional experienced with groundwater sampling and decommissioning seven (7) monitoring wells located at the Seba Dalkai Boarding School, Seba Dalkai, Arizona. The ground water monitoring wells have not been sampled since 2005 and requires sampling. The sampling results will determine No Further Action concurrence from U. S. Environmental Protection Agency (EPA) and the Navajo Nation Environmental Protection Agency (NNEPA) before decommissioning is conducted. The Bureau of Indian Affairs (BIA), Navajo Region, Branch of Environmental Management (BEM) currently does not have a project report or a map showing the locations of the seven (7) ground water monitoring wells located at the site. Research of the project files was conducted, and no information on the groundwater monitoring wells were found. A letter dated 2005 by EDI was located which summarized the sampling that was conducted at the Seba Dalkai Boarding School site and provided in the Background section. Attached is the previous school layout of the buildings and utilities at the school. (Attachment 1)

Since the ground water sampling has not been sampled since 2005, sampling of groundwater is required to obtain the most current ground water data for the 7 monitoring wells. The selected contractor shall sample the seven (7) groundwater monitoring wells. The testing results will determine if BIA NRO BEM will request concurrence; No Further Action document from USEPA Region 9 and Navajo Nation Environmental Protection Agency (NNEPA) to remove the groundwater monitoring wells.

Background:

The Seba Dalkai Boarding School is located Seba Dalkai, Arizona. In March 2004, the USEPA Letter EPA Docket No. RCRA -09-95-0004 was sent to the Bureau of Indian Affairs (BIA) on 23 compliance items there were outstanding. One of these items was the Seba Dalkai Boarding School, where the old school was demolished, and the associated aboveground storage tanks (ASTs) and underground storage tanks (USTs) were removed in 2000 and 2001.

The investigations of the soils at the former tank sites were conducted by Western Technologies, Inc., in February and March 2001, and hydrocarbon-contaminated soils were found at many sies.

Some of the analytical data were unusable, due to the analytical laboratory did not use the proper practical quantifiable limits (PQLs) for EPA Method 8015 for diesel range organics (DRO).

Sites that were contaminated above the 100-ppm limit were UST-1 and UST-2 sites near the former building 417, the south end of the AST site near building 417, two USTs sites southeast of building 411. Soils were excavated by Ironhorse beneath the USTs located near the former building 417 and were disposed at the Pen-Rob Landfill, Joseph City, AZ. Five monitoring wells were installed in February 2002, but groundwater sampling has not continued. Groundwater contamination was found in one monitoring well 3 (MW3).

On March 11, 2004, the BIA prepared a Response to USEPA Letter EPA Docket No. RCRA-09- 95-0004, which stated that an organized program of ground-water monitoring would be instituted, which may include the addition of more groundwater monitoring well. (EDI, October 2005 Letter).

The initial groundwater investigation consisted of two quarters of groundwater sampling to determine whether the groundwater requires remediation. Two additional monitoring wells (MW6 and MW7) were installed in the southwest corner of the school grounds in August 2004 to detect any contaminants that may have migrated in that direction. Groundwater flow appears to flow in a northwesterly direction at the site. These wells, in addition to the five monitoring wells already present at the site, were sampled four times within one year period. More rigorous sample collection and analytical procedures were used to ensure data quality. Sample dates were September 4, 2004; December 14, 2004; February 28,2005 and August 26, 2005. Groundwater samples were tested for benzene, toluene, ethylbenzene, and xylenes (BTEX), total petroleum hydrocarbons (TPH), other volatile organic compounds (VOCs) and metals.

The result of the testing identified BTEX at the levels near 1.4 micrograms per liter (parts per billions) at monitoring well #3 (MW3). As stated in the September 2005 ground-water investigation report, the ethylbenzene appears to naturally attenuate, as it was undetected in samples collected. Small amounts of TPH were detected in MW1, MW2, MW3, MW4, MW6, MW7. The levels identified is not a health risk and has no aquifer water quality standard, such as BTE. Chloroform was present in MW2 and MW6 at levels below 10 milligrams per liter, which is less than the USEPA maximum’s contaminant level of 80 milligrams per liter. Because Chloroform is byproduct of chlorine disinfection used in wastewater treatment, there were concerns on the sewer lines could be leaking into the ground water. A dye tracer test was performed in September-October 2005 and no dye was detected in the ground water in MW2 and

MW6.

The conclusion of the EDI letter recommends based on the testing results at that time, no contaminants were present in the ground water and water used for drinking water are impacted.

There does not appear to be sufficient contamination in the soil to require removal. No health impacts or risk to children or other occupants of the school. The recommendation states this site does not require ground water or soil remediation and the seven (7) monitoring wells should be plugged and abandoned upon concurrences of the USEPA and the Navajo Nation EPA.

Although the recommendation was to plug and abandoned the ground water monitoring wells, BIA recommendation is to remove the groundwater monitoring wells unless removal will cause other environmental concerns.

Period of Performance: The work shall not to exceed 120 days.

Task I – Pre- Work Submittals and Consultation:

The contractor shall consult, conduct a site inspection, data review and provide required submittals and:

1. Conduct site visit and inspection of existing area to locate the seven (7) monitoring wells for preparation of work plan.

2. Prepare detailed work plan and work schedule for submittal to BIA for review and approval to include water sampling and decommissioning of GW wells.

3. Prepare a Health and Safety Plan (HASP) in accordance with 29 CFR 1910.120 to assure worker protection and public. The plan shall include current certifications and medical surveillance documentation for workers who will be on site. HASP should also contain COVID-19 protocols for employees at the work site.

4. The contractor shall conduct a survey to locate underground infrastructures in order to properly locate monitoring wells for removal. Finding will be used to preclude instances of direct contact and damage to the developments.

5. Research of available information on the 7 groundwater monitoring wells and work conducted in 2005 at the site.

6. Permit application for submittal to the Navajo Nation Water Resources Department with payment. The Contractor will prepare and submit the proposed detailed work plan and schedule, all applicable well closure permits from the Navajo Nation.

Task 2 -Groundwater Sampling of the seven (7) monitoring wells.

1. Locate the seven (7) groundwater monitoring for sampling through research and site visit.

2. Groundwater sampling is required to ensure no contaminates exist to receive concurrence from regulatory agencies to approve removal of the GW monitoring wells.

GW Wells shall be tested for benzene, toluene, ethylbenzene, and xylenes (BTEX), total petroleum hydrocarbons (TPH), other volatile organic compounds (VOCs) and metals.

3. Water samples shall be submitted to certified laboratory for analysis.

4. Correspondence preparation to USEPA and NNEPA of groundwater results shall be prepared by contractor. If requested for a presentation by the regulatory agencies, contractor shall prepare a power point presentation of the water testing results

5. Contractor available to provide presentation to USEPA and NNEPA if requested on sampling results and next actions.

Task 3 – Excavate, remove, plug, and abandon seven (7) GW wells

1. Based on the GW sampling results and response back from the regulatory agencies as

No Further Action, the contractor shall proceed to excavate/pull/abandoned the 7 GW wells which are located at the Seba Dalkai Boarding School site.

2. The contractor shall conduct a Bluestake survey to locate underground infrastructures to properly locate monitoring wells. Finding will be used to preclude instances of direct contact and damage to the developments.

3. Monitoring wells are located near Building 417 and 411 at the Seba Dalkai Boarding School, however other locations were not identified in the EDI letter.

4. There is no information on the location of the other 5 remaining GW wells or depth below ground surface. The project was conducted in 2005, BEM could not find any reports on the site with exception of the October 2005 EDI letter.

5. Determination shall be made by contractor if these groundwater wells are constructed of slotted PVC pipe and cemented at ground level to prevent unauthorized access.

6. Wells are to be plugged and abandoned in accordance with the Navajo Nation Water Code and the ASTM D 5299-2010 Standard Guide for Decommissioning Ground Water Wells, Vadose Zone, Monitoring Devices, boreholes, and other Devices for Environmental Activities

Deliverables:

Report:

The deliverable report for this work shall cover the work done in providing the ground water sampling results and the decommissioning to include, but is not limited to, the following information:

Summary of the work completed.

Description of the field work performed Recommendations additional action to the existing workplan schedule.

Photographs, drawings locating the area on a map to the 1” equals 100’scale sufficient to locate former wells sites and GPS coordinates of the these well sites.

Certification that the wells are closed in accordance with the Navajo Nation Water Code and the ASTM D 5299-2010 Standard Guide for Decommissioning Ground Water Wells, Vadose Zone, Monitoring Devices, boreholes, and other Devices for Environmental Activities

A draft report will be submitted to BIA NRO BEM within 15 days following completion of the field work. Following review and approval of the draft document by BIA, the Contractor shall edit and prepare the final report stamped by a Registered Professional Engineer certifying that the work was done in accordance with the approved work plan and Federal Regulations and submit three copies and one electronic copy in MS Word.

Special Conditions:

The contractor is responsible for any utilities that are damaged during the work and shall repair them immediately at no cost to the Government. Any damage to grassed areas or concrete structures other than those directly affected by the project will be repaired at the Contractor’s expense.

The contractor will adhere to all applicable tribal laws and regulations, and payment of tribal taxes

No drugs, smoking or alcohol use are allowed at the Seba Dalkai Boarding School site. Workers shall avoid contact with students on campus. BIE POC will be designated.

All contact with the public, private or regulatory community shall be made through the BIA, NRO BEM Regional Environmental Scientist or the designated BIE contact at the Seba Dalkai Boarding School. No information may be released without the written consent of the BIA Navajo Region.

The contractor shall be responsible for the timely payment of all subcontractors and invoices generated during the performance of work at the project.

Requirements: Pre-work conference

Place of Performance: Field activities are to commence at the Seba Dalkai Boarding School site, Seba Dalkai, Arizona.