VICK_07-106-1_SOW_SUPPLEMENTAL_LSI.pdf

SCOPE OF WORK

The National Park Service (NPS) is seeking a proposal to conduct a Supplemental Limited Subsurface Investigation (SLSI) of a portion of a 137-acre unimproved parcel of land located in Edwards, Mississippi, approximately 20 miles east of Vicksburg. The property is currently owned by the Mississippi Department of Archives and History (MDAH) and is more particularly depicted on the attached location map prepared by the NPS. As tax-exempt parcels in Hinds County are not always assigned a street address, the Hinds County's parcel identification number associated with the specific portion of land upon which the SLSI will be conducted is provided below to assist you in your initial research of the property and its surroundings.

Pcl. ID # Owner Acres 4966-724 Mississippi Dept. of History & Archives 15

BACKGROUND:

The 15-acre parcel identified above together with two adjoining parcels comprise the 137-acre tract of land the MDAH intends to donate to the NPS as an addition to Vicksburg National Military Park, Champion Hill Unit. As part of our requisite due diligence, a Phase 1 ESA of the entire 137-acre property was conducted in April 2019. As an active railroad right-of-way and the subject property share an approximately 1,200-foot common boundary, risk of potential contamination from the railroad’s operations moved the NPS to conduct a Limited Subsurface Investigation (LSI) of the land located immediately adjacent to the southern railroad right-of-way in October 2019. The 2019 LSI ‘s scope specified the advancement of ten (10) soil borings immediately adjacent to the railroad right-of-way at intervals of 100 feet. Two soil samples were collected from each boring; a sample at the surface and a second sample collected at a depth of between 3-4 feet below grade. Each sample was submitted to a certified laboratory and analyzed for Volatile Organic Compounds (VOCs), Polycyclic Aromatic Hydrocarbons (PAHs), Total Petroleum Hydrocarbons (TPHs), Diesel Range Organics (DROs), total metals, herbicides, pesticides (organochlorine), and polychlorinated bi-phenyls (PCBs).

A summary of the results from the laboratory analyses of collected soil samples are as follows:

• Aside from the presence of Acetone at levels below the Mississippi Department of Environmental Quality Tier 1 Target Remediation Goals (TRGs) and likely due to residual contamination associated with laboratory glassware cleansing or the reaction between the sample bottle preservative and natural compounds in the soils, no other VOCs compounds were detected in the soil samples submitted for analysis.

• No herbicides, pesticides or PCBs were detected in the soil samples submitted for analysis.

• Arsenic, iron, manganese and phosphorus were detected at levels above their respective

Tier 1 TRGs for areas of unrestricted soil use. No other metals were detected above their respective Tier 1 TRGs. MDEQ has published literature indicating that concentrations of arsenic above its respective Tier 1 TRG naturally occur in this region of Hinds County, MS.

Arsenic in concentrations above the Tier 1 TRG was detected in 13 of the 24 samples analyzed and in 10 of the 12 borings dug advanced.

The environment in which the soil samples were collected is primarily wooded land located within a floodplain that contains decomposing organic materials that release organic phosphorus during plant decomposition. Phosphorus in concentrations above the Tier 1 TRG was detected in all 24 samples. Due to the presence of phosphorous in consistent concentrations and acknowledging the environmental setting conducive to organic decomposition from which the samples were collected, the presence of phosphorous as a naturally occurring byproduct of organic decomposition is the likely source.

Iron and manganese in concentrations above Tier 1 TRGs was detected in one sample respectively of the 24 samples analyzed.

• PAH compounds in concentrations above the Tier 1 TRGs were detected in the surficial (0’-

1’) soil samples collected from soil borings SB01, SB02, SB03 & SB04, the soil borings closest to Baker’s Creek and within the property’s lowest elevation. The floodplain of Baker’s Creek is periodically inundated during periods of heavy rainfall. These compounds were not detected in the subsurface (3’-4’) soil samples from soil borings SB01-SB04, nor were they detected in any of the western 8 borings of higher elevations. located within

• Although TPH diesel range organics were detected in six samples, concentration levels did not exceed Tier 1 TRGs.

Summary of Conclusions: Analysis of the data compiled in Tables 1a-1d of the LSI, indicates a reasonable likelihood that both arsenic and phosphorus naturally occur in the subject property soils. The presence of iron and manganese in concentrations above MDEQ Tier 1 TRGs occurs in only one sample respectively of 24 samples analyzed. The presence of PAHs in concentrations above Tier 1 TRGs are found only in the surficial samples collected from soil borings at the property’s lowest elevation and in proximity to Baker’s Creek, indicating the possibility that these compounds may have been deposited by flood waters overrunning the banks of the creek and retained in place by high water and the railroad berm during heavy rainfall.

Although the LSI revealed the presence of soil contaminates on the property, the source and extent of the contamination remain in question. Several factors lead to this uncertainty, including the potential for certain metals (arsenic and phosphorous) to be naturally occurring on the property, the anomaly of iron and manganese in concentrations above Tier 1 TRGs in one of 24 samples collected and analyzed, and the potential for flood waters from Baker’s Creek to act as the pathway for contaminates to be deposited onto the property as evidenced by the presence of PAHs above Tier 1 TRGs found only in surficial soil samples collected from borings in the northwest corner of the property. In an effort to answer these questions, additional soil sampling and analyses is necessary to better determine the extent and source of the contamination on the property.

PROPOSAL FOR SUPPLEMENTAL LIMITED SUBSURFACE INVESTIGATION

The proposed acquisition of the 137-acre subject property by the NPS has been deferred for the past 18-months due to the presence of contamination identified on the property. The laboratory analyses of soil samples collected from land immediately adjacent to an active railroad line, which serves as the property’s northern boundary indicated the presence of regulated compounds above Tier 1 TRGs in varying consistencies. Acknowledging that no direct connection has been made between railroad activities and the identified contaminates on the subject property and that the subject property’s historic use continues as undeveloped, wooded and agricultural land, further soil sampling and analysis is required to determine the extent and source of the contamination on the property. Upon reaching these determinations, the NPS will be better equipped to assess viable acquisition options. The specific objectives of this proposed supplemental sampling and analyses initiative are to ascertain the following information:

1. Determine whether arsenic and phosphorus in concentrations above Tier 1 TRGs are naturally occurring in the property’s soils beyond the previously sampled land immediately adjacent to the railroad.

2. Determine whether concentrations of iron and manganese above Tier1 TRGs found in singular soil samples collected and analyzed as part of our previous investigation are anomalies or extend beyond immediate proximity to the railroad.

3. Determine whether the presence of PAHs in concentrations above Tier 1 TRGs, found in samples taken from the property’s northwest corner, is isolated to this portion of the property or extends to other portions of the property.

4. Determine whether Baker’s Creek can reasonably be identified as a pathway for contamination, specifically the presence of PAHs, found on the subject property.

5. Determine through the design and implementation of a comprehensive soil sampling and analyses plan and associated laboratory analyses’ results, acquisition options intended to preserve the NPS’s innocent landowner liability protections and allow for the safe enjoyment of the property by park visitors.

To ensure all relevant data regarding the extent and source of contamination in the subject property is obtained to inform the NPS’s decision regarding the proposed acquisition of the property, the contractor’s comprehensive soil sampling and analyses plan must include the two major initiatives described below:

1. Establish Alternative Northern Boundary of a Potential Partial Acquisition by NPS

Recognizing the possibility that contamination may exist only in proximity to the existing railroad and that remediation by either the MDAH or the NPS is not a feasible option, a partial acquisition of the property incorporating a northern boundary located at a uniform offset from the railroad to exclude the acquisition of land with contaminated soil is a logical alternative. To ascertain whether a partial acquisition is a viable alternative, the advancement of soil borings at intervals of 100’ along a line measured at a right angle 100-feet distant and parallel to the property’s existing northern boundary is required. The contractor shall utilize GPS technology in identifying the location of the proposed alternative northern boundary as described above and provide field stakes marking the intersections of the alternative northern boundary with the property’s existing eastern and western property lines as well as the location of each soil boring. Identifying the proposed alternative northern boundary in the field will greatly assist the NPS in obtaining a field survey of this new property line should the results of laboratory analyses of samples collected from borings dug south the proposed alternative northern boundary indicate the absence of contamination.

2. Obtain a Comprehensive Understanding of the Extent of Contamination on the Subject

Property A. To obtain a more comprehensive understanding of the extent and source of contamination on the subject property, the contractor is required to design a soil boring/sampling plan for review and approval by the NPS. The scope of the sampling plan shall include the collection of two samples; one surficial sample (0’-1’) and one sample taken at a depth of between 3’-4’ below grade from each hand-augered soil boring. Additional sampling beyond the two sample/per boring minimum is required should observed and recorded soil conditions warrant supplemental sampling. Should groundwater be encountered in any of the borings, a groundwater sample shall be collected in lieu of a second soil sample. A sufficient number of samples shall be collected from random locations throughout the property to enable an environmental professional to reasonably determine whether contamination is limited to land immediately adjacent to the railroad or is more widespread across the property. The design of the soil boring/sampling plan must also include efforts to address the following questions:

1. Is the presence of arsenic and phosphorous on the property naturally occurring?

2. Are concentrations of iron and manganese above Tier 1 TRGs as found in singular samples collected in proximity to the railroad anomalies or are these metals present in similar concentrations at other locations on the property?

3. Are concentrations of PAHs above Tier 1 TRGs present in locations other than the northwest corner on the property adjoining the railroad and Baker’s Creek? If not, does the data compiled by the SLSI provide evidence that Baker’s Creek is the source of these contaminates?

B. Each collected soil sample shall be analyzed for the following substances:

• Volatile Organic Compounds

• Herbicides, Pesticides & Polychlorinated Bi-phenyls (PCBs)

• Metals

• Polycyclic Aromatic Hydrocarbons (PAH)

• Total Petroleum Hydrocarbons (TPH)

The SLSI is intended to evaluate the extent to which soil/groundwater contamination is present in addition to effectively determining the source(s) of contamination found on the property.

The following project scope of work outline is provided to assist you in preparing your quotation:

• Initial Field Reconnaissance - The Contractor shall obtain utility clearance from Mississippi

811 utilities protection center, or equivalent "call before you dig" authority prior to initiating any field work. The Consultant shall perform a visual assessment of the entire work area, affording careful consideration to each proposed boring location, to avoid injury to personnel or damage to existing utilities. Hand-auguring or manual probing is the preferred method for obtaining soil and groundwater samples to avoid contact with any underground utilities.

• Soil Boring Plan – The Contractor shall prepare a boring plan for review and approval by the

NPS depicting the approximate locations of all proposed borings. The Boring Plan shall include a narrative description of how the placement and quantity of the proposed borings will serve to achieve the goals of the SLSI as stated herein. The Boring Plan shall also indicate the number of borings to be advanced, the distance interval between the next closest boring for each proposed boring, and the distance offset from the railroad’s southern right-of-way line for each proposed boring. The railroad right-of-way is identified on Hinds County tax maps as being 80-feet wide along the subject property's northern boundary. Thus, a distance of 40 feet from the center of tracks would approximate the railroad’s southern right-of-way line. The Contractor shall exercise the utmost safety protocols when personnel are within proximity to said right-of-way line.

• Sampling Protocol - Hand augur borings shall be advanced to a depth of 4-feet below ground surface, augur refusal or groundwater, whichever is encountered first. The Contractor shall observe and record soil conditions throughout each of the hand-augured borings. A minimum of 2 soil samples are to be collected from each boring, including one surficial sample, and a second sample taken at a depth of between 3’ and 4’ below ground surface.

• Sampling Analysis - The field samples are to be submitted for analysis by a certified laboratory for the following constituents:

1. Volatile organic compounds (VOCs)

2. Herbicides, Pesticides, and Polychlorinated Bi-phenyls(PCBs)

3. Metals

4. Polynuclear aromatic hydrocarbons (PAHs)

5. Total petroleum hydrocarbons (TPH) diesel range organics (DRO) by modified EPA 8015

• Project Reporting - A Supplemental Limited Subsurface Investigation (SLSI) report shall be prepared in accordance with ASTM Standard E1903-11 – for Phase II Environmental Site Assessments and 40 CFR 312.10 upon the Contractor’s receipt of laboratory analytical data. The SLSI shall include a description of methodologies employed, sample location rationale, field observations, and laboratory analyses results. The report shall include a narrative interpretation of the sampling analyses supported by regulatory documentation, tables, figures and sampling analyses data.

• Cost and Schedule - The Contractor shall provide a total cost to perform the work described herein and provide a schedule for completing the work.

The above tasks shall be completed in accordance with all applicable guidelines and methodologies and shall be completed under the direction of an environmental professional.

Please submit your proposal on company letterhead, at your earliest convenience. Thank you for your time and attention to our request. If you have any questions or require any additional information, please contact me at your earliest convenience.

Joe Cook, Realty Specialist National Park Service Land Resources Program Center

(410) 531-7644