2024-7-10 No.2_RFI_answers.docx

SOLICITATION W50S8N-24-B-0001

PRE-BID INQUIRIES

Date of Bid Inquiry: 10 July 2024 From: Sean Carney Company Name: ENVECO Environmental Solutions, LLC Address: 103 Manor Lake Estates Drive, Spring Texas 77379 Phone Number: 607-259-7017 Emal Address: scarney@envecoenvironmental.com

1. Based on Government responses to RFIs, it is stated that only petroleum impacted soils will be disposed of offsite; however, groundwater and soil at the site is assumed to contain PFAS. Based on PFAS being a contaminant of concern, offsite disposal of any petroleum contaminated soil generated from the site will require PFAS testing. If PFAS is detected in the petroleum contaminated soil will this be considered a change in condition and what is the fate of this soil? This is assumed a PFAS impacted site. Currently there are no regulatory disposal threshold requirements for PFAS. Contractor is expected to find a disposal site that will accept petroleum and PFAS contaminated soils. Contractor is burdened with completing characterization required for selected landfill disposal authorization. All soils disposed will be completed under manifest. Copies of manifests and weight tickets must be submitted to contracting upon project completion.

2. Does the tank field include observation wells? If yes, please provide current depth to water readings from these wells (i.e., depth from surface grade). Water level as of 10-Jul, (1500), is 8’-2” BGS

3. Based on Government responses to RFIs, it is stated that PFAS is present in an upgradient groundwater monitoring well and this is the basis for assuming excavation water contains PFAS. Please provide the groundwater elevation data and PFAS concentration detected in this well. The concentrations of PFAS dictate the management and level of treatment of excavation water. For this project assume a PFAS concentration of 1,300 ng/L (ppt) in the groundwater.

4. Does the compaction standard of 90-95% for each 12-inch lift of placed backfill require verification by a qualified engineer via density testing? Compaction documentation, (density testing), must be provided to the Contracting Office. Density testing utilizing equipment with a radioactive source will need to be reviewed by our Bioenvironmental Engineering Office.

5. SOW Section 3.3.2.1.3 states that PFAS levels must be below 10 ng/L following EPA Method 1633 for discharge; however, the finalized EPA Method 1633 may achieve detections limits as low as 1.0 ng/L. Additionally, to discharge under the Onondaga County Wastewater Treatment facility’s permit requirement, PFAS must be at non-detect levels following EPA Method 1633. Onsite treatment to non-detect levels may not be achievable; thus, is offsite disposal a viable alternative to manage the 20,000 gallons of excavation water? Acceptable regulatory levels for PFAS in environmental media have not been established. While the intent is to bring levels of PFAS contamination in groundwater down to “Non-Detect” prior to leaving site, we are adhering to the NYS DEC guidance threshold levels for PFOA, PFOS and 1, 4-Dioxane identified in an addendum to Technical and Operational Guidance Series, (TOGS) 1.1.1-Ambient Water Quality Standards and Guidance Values and Groundwater Effluent Limitations, issued February 2023. Threshold values are:

a. PFOA: 6.7 ng/L (ppt)

b. PFOS: 2.7 ng/L (ppt)

c. 1,4-Dioxane: 0.35 ug/L (ppb)