Questions_-_2-BACA_1-Haystack_SDV_140A0926Q0006_(1)_0002.pdf

2-BACA_1-HAYSTACK SHEEP DIP VAT (SDV)

SOLICITATION 140A0926Q0006

Questions

1. SOW, Page 1 – Introduction:

The SOW indicates that the sites will be “resampled to confirm that no hazardous substances remain.” Can the Government provide any previous investigation reports, sampling data, or assessment reports (e.g., Preliminary Assessments or prior sampling results) for the Baca #1, Baca (New), and Haystack SDV sites to inform resampling efforts?

BIA BEM has been utilizing past SDV reports supplied by the Navajo Nation EPA;

however, these reports are currently unavailable. Although toxaphene sampling was previously conducted at these sites, soil sampling for contamination is required for all three locations.

2. SOW, Page 1 – Introduction:

The SOW notes that sheep dip vat operations have historically been associated with various regulated chemicals and that comprehensive sampling is required.

In addition to toxaphene analysis using EPA Method 8081A, is the Government requesting analysis for any additional analytes?

Sampling will follow EPA Method 8081A. The common chlorinated pesticides at these Navajo Sheep Dip Vats (SDVs) include Toxaphene, Lindane, and Dieldrin.

Coumaphos, an organophosphate pesticide, was also frequently used. The contractor will use professional expert judgment.

3. SOW, Page 2 – Background (Baca New SDV):

The SOW states that “car parts and trash are scattered in the immediate vicinity of the vat.” Can the Government provide additional detail on the general type, size, and approximate quantity of debris anticipated for removal to assist with disposal planning and cost estimating?

The general waste debris at the site is estimated to be less than 20 cubic yards.

Please refer to the attached photos for more details. Contractors are invited to visit both Baca sites. However, the Haystack site is currently locked and will only be accessible when the project starts. Please note that the site visit will be at the contractor's own expense.

4. SOW, Page 2 – Background / Task II.B.2:

The SOW states that “the Haystack SDV is located approximately 90 feet west of water well 16T-552.” Is this well considered an “available water source” requiring sampling under Task II, Subsection B.2, or should sampling be limited to surface water, ponds, cisterns, or downgradient water sources only?

Yes.

5. SOW, Page 4 – Task IV (Removal):

The SOW requires removal of all structural components and solid waste materials in the immediate vicinity of each SDV site. Can the Government clarify whether removal is limited to visible surface debris only, or if partially buried debris and materials outside the immediate vat footprint are also included in the removal scope?

Removal includes all visible debris including those partially buried.

6. General / Tasks III–V:

Can the Government provide estimated volumes or quantities of contaminated soil, concrete, and debris requiring removal based on previous investigations or site visits? Given the remote nature of the sites and mobilization constraints, clarification on whether removal quantity estimates exist would assist with planning and cost development.

Similar projects have estimated the removal of approximately 900 cubic yards of soil. In the last project, 554 tons of concrete and contaminated soil were disposed

of. The quantity of soil disposal will depend on the level of contamination.

7. Task VII – Reports:

Can the Government clarify if their preference is for the contractor to prepare three separate final reports (one per SDV site) or a single consolidated report that encompasses all three SDV sites with site-specific sections?

One final report, clearly separating the three projects, will be sufficient.

8. Can you clarify how the sampling grid is to be implemented in Task 2? Is the sampling grid to be utilized for both tasks 2 and 3 (with any additional necessary extensions in task 3).

Sampling grid will be utilized for both tasks. Sampling grid information is for use by the contractor to determine extent of soil contamination and excavation efforts.

9. Do you have a copy of the 1999 PA for Haystack available for review Attached is 1999 PA for Haystack which is identified as “Old Baca-Haystack Dip Vat”.

10. Any other previous investigations at the two Baca SDVs?

No, due to the lack of historical reports.

11. Is there an estimated quantity of solid waste materials around the vicinity of the SDV sites (ex: tires, car parts, and other debris) General waste debris is estimated to be less than 20 cubic yards.

12. Please confirm that 121 borings will be required at each SDV.

Boring is based on sample grid.

Haystack SDV

Baca (New) SDV

Baca (Old) SDV