Gill Street Park Pre-regulatory landfill Site
Gill Street Park – Pre-Regulatory Landfill Site
North Gill Street, Zebulon, Wake County, NC
Site ID: NONCD0000201
Site Overview
NCDEQ’s Division of Waste Management, through its Pre-Regulatory Landfill (PRLF) Unit, is conducting a remedial investigation of the Gill Street Park (the Site). The Gill Street Park Site is a PRLF located in Zebulon, North Carolina. The Site is located on portions of at least nine parcels (approximately 3.64 acres) along North Gill Street, North Privette Street, and East Stronach Avenue. The opening date of the landfill is unknown but historical records show the landfill operated from at least 1964 to 1968 and may have included incinerated waste.
PRLF is in the process of conducting a comprehensive investigation of the landfill where the goal is to establish the location of the waste disposal area and the extent of associated impacts (i.e., contamination). As evidence of the landfill and/or its associated impacts are observed to extend onto adjoining/nearby properties, the investigation will also extend to those properties until the extent of impacts above regulatory standards are identified. Investigation findings will be used to prepare a Remedial Action Plan (RAP) that details a potential risk-based remedy to address risks identified.
The completed and planned remedial investigation activities for the Site are outlined below and will be updated when completed with a link to the associated report.
A general information sheet regarding Gill Street Park can be found here: Gill Street Info Sheet (English) Gill Street Info Sheet (Spanish)
For general information about the PRLF Program, please visit the link below:
First Phase Investigation
A First Phase Investigation Report dated March 27, 2025 summarizes the historic and current land use, potable water usage, sensitive environments evaluation, water supply well survey, description of geologic/hydrogeologic conditions, and results of an initial geophysical survey of the horizontal extent of waste where access could be garnered at the time of the first phase activities.
The Site is improved with a municipal park and contains features including playground equipment, a basketball court, and picnic tables. The Site is bounded to the north by undeveloped wooded land and an unnamed tributary to Little Creek, to the east by a cemetery, and to the south, west, and northwest by residential properties.
Report: First Phase Investigation Report March 27, 2025
Water Supply Evaluation
A report dated April 10, 2025 summarizes the developed properties with public water service and/or private wells within the 1,000-foot vicinity of the Site.
Report: Task Order WS24-RAL(d) Report – April 10, 2025
Remedial Investigation and Waste Disposal Area Delineation
Remedial investigation activities were conducted at the Site between June and December 2025. These activities included background soil sampling, waste disposal area (WDA) delineation borings, monitoring well installation and groundwater sampling, water supply well sampling, and vapor assessment.
Background metal samples were collected from undeveloped areas within the vicinity of the Site to evaluate naturally occurring metals concentrations. These background results are used as a comparison point when evaluating soil samples collected from other areas at the Site.
The WDA delineation borings confirmed the extent of the waste on the Gill Street Park property, vacant/undeveloped property to the north, and residential properties to the west and south. Additional work is needed to confirm the extent of the waste into the southern residential properties beyond East Stronach Avenue. Waste encountered at the Site includes glass, metal, brick, and porcelain.
Groundwater monitoring wells were sampled in July and November 2025. The laboratory reported detections of several constituents above the NC 2L Groundwater Standards. Groundwater flow direction appears to be to the north-northeast.
One inactive water supply well was sampled in November 2025. This residential water supply well is located approximately 1,050 feet northwest of the Site. The well water was analyzed for volatile organic compounds (VOCs). The laboratory report indicated there were no detections of VOCs above respective NC 2L Groundwater Standards for the water supply well.
In July 2025, landfill gas and soil gas were screened and sampled for VOC analysis at 20 locations throughout the WDA and in close proximity to several residential properties.A sample from the on-Site landfill gas probe indicated a concentration of tetrachloroethylene (PCE) above the Residential and Non-Residential Sub-Slab and Exterior Soil Gas Screening Levels. Soil gas samples collected across the WDA and in close proximity to several residential properties indicated low-level concentrations of VOCs. The NCDEQ Risk Calculator was used to assess the risk for the soil gas to indoor air pathway for the individual landfill gas and soil gas sample locations. Risk was exceeded in the landfill gas sample location within the central portion of the Gill Street Park property; however, no structures are currently present within this area. The risk associated with the soil gas to indoor air pathway was exceeded at one additional residential property along North Gill Street; however, a crawl space air sample was collected, which did not indicate an unacceptable risk to the residents.
These activities and results are summarized in a report dated March 6, 2026
Soil Cover Evaluation
Soil samples were collected from the top 12 inches (or to the top of waste within 12 inches) to evaluate potential risks to users and the suitability of the existing soil for use as a permanent cover. The evaluation process involved applying a grid approximately 100-feet by 100-feet over the Gill Street Park area and a grid approximately 50-feet by 50-feet within the residential areas for the advancement of at least five borings in each grid. The sampling protocol included one discrete soil sample from each grid for VOC analysis and one composite sample comprised of five separate soil borings within each grid for analysis of metals, semi-volatile organic compounds, sulfate, nitrate, nitrite, ammonia, and hexavalent chromium.
NCDEQ risk levels for Residential (Unrestricted) Use and/or EPA Residential Screening Levels (RSLs) exceeded at 17 of 24 sample grids/locations. Lead is the primary driver of the risk exceedances for the areas evaluated. Additionally, soil cover thickness is less than 12-inches in several areas of the WDA.
Map: Soil Cover Evaluation – Risk Exceedances
Report: Soil Cover Evaluation Report – March 12, 2026 [RI-5 Report]
Additional Waste Disposal Area (WDA) Delineation
Additional borings are needed to further evaluate the horizontal extent (footprint) of the WDA along the southern boundary near East Stronach Avenue, pending access approval from property owners. This will also provide some information on the vertical extent (waste thickness) for the remaining area of the WDA.
Map: Waste Disposal Area Delineation Map
Soil Cover Evaluation
Pending the results of the additional WDA delineation activities, borings and analytical soil samples from the top 12-inches in approximate 50-foot by 50-foot grids will be advanced and collected to evaluate potential risks to users and the suitability of the existing soil for use as a permanent cover within the southern WDA.
Groundwater Investigation
Construction and sampling of at least one additional monitoring well is needed to determine if groundwater quality has been impacted to the south of the WDA. Multiple rounds of groundwater sampling will be conducted. The results of the first sampling event (July and November 2025) are provided below.
Map: Groundwater Potentiometric Map
Map: Groundwater Constituent Concentration Map
Vapor Assessment
Construction, screening, and sampling of landfill gas probes, soil gas probes, and crawl space /indoor air (if needed) to document conditions and determine if vapor intrusion to nearby structures is of concern due to historical landfilling activities. Multiple rounds of vapor intrusion sampling will be conducted. The results of the first sampling event (July 2025) are provided below.
Figure: Landfill Gas, Soil Gas, Flux Chamber, and Crawl Space Air Results Map
Surface Water/Sediment Investigation
Sample collection of surface water and/or sediment from the stream adjacent to the site.
Remedial Investigation Summary Report
Once the remedial investigation is complete, a report summarizing the results of the investigation activities will be completed.
Draft Remedial Action Plan (RAP)
A report detailing a potential risk-based remedy that addresses potential risks identified during the remedial investigation. As part of these activities, a survey of the site will be completed for mapping purposes and planning of potential remediation activities. The Draft RAP will be posted for public comment prior to implementation.
PRLF Contact Info
Ziqiang Chen
PRLF Project Manager
(919) 707-8347
For general information about the PRLF Program, please visit the link below:
Documents and data for the site, including investigation results, will also be posted to the following link:
Link to Site Documents – Gill Street Park