PFAS Investigation and Groundwater Monitoring at the Former MOD Airfield Fire Training Facility
This project involved a comprehensive ground investigation and long‑term groundwater monitoring programme at a former Ministry of Defence Fire Training Area, where our team assessed soil and groundwater conditions to determine the presence and extent of PFAS contamination ahead of planned redevelopment.1624016240
Challenge
The end client for this project was a government entity that sought to redevelop a derelict area of land near a former military facility for business and commercial use. The site, previously owned by the Ministry of Defence (MOD), had a history of being used as a Fire Training Area (FTA) post-World War II, raising concerns about chemical contamination, specifically PFAS (per- and polyfluoroalkyl substances), commonly known as "forever chemicals."
A consulting engineering firm served as the project engineer, while SOCOTEC was commissioned to conduct a detailed ground investigation to assess ground and groundwater conditions.
PFAS contamination presented a unique challenge due to the prevalence of PFAS in the environment from everyday materials, posing a high potential for cross-contamination of the samples. Ensuring accurate sampling without cross-contamination was a key logistical and technical hurdle. Our field team, in collaboration with subcontracted drillers, had to implement stringent protocols to avoid introducing contaminants during the sampling process.
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Project Description/Overview
Project Description/Overview
Our responsibility was to produce a detailed ground investigation report that would inform the client about the condition of the land, focusing on identifying any PFAS contamination. This report was intended to help the government entity assess the site's safety for redevelopment. As PFAS is a significant contaminant of concern due to its persistence in the environment, our primary objective was to establish the presence and extent of contamination and provide the necessary data to guide further remediation if required.
Our scope of work included:
- Drilling multiple boreholes and installing monitoring wells across the site to assess soil and groundwater quality
- Excavating trial pits to gather soil samples
- Conducting surface and groundwater sampling for a wide range of contaminants, including PFAS
- Installing long-term groundwater monitoring loggers within selected boreholes to monitor changes in groundwater levels and potential contaminant migration over a 12-month period
Our responsibility was to produce a detailed ground investigation report that would inform the client about the condition of the land, focusing on identifying any PFAS contamination. This report was intended to help the government entity assess the site's safety for redevelopment. As PFAS is a significant contaminant of concern due to its persistence in the environment, our primary objective was to establish the presence and extent of contamination and provide the necessary data to guide further remediation if required.
Our scope of work included:
- Drilling multiple boreholes and installing monitoring wells across the site to assess soil and groundwater quality
- Excavating trial pits to gather soil samples
- Conducting surface and groundwater sampling for a wide range of contaminants, including PFAS
- Installing long-term groundwater monitoring loggers within selected boreholes to monitor changes in groundwater levels and potential contaminant migration over a 12-month period
Solution
Solution
The project was divided into two key phases:
Phase 1: Ground Investigation
This phase focused on the drilling of boreholes, excavation of trial pits, and sampling of soil and water at various depths.
Phase 2: Long-term Groundwater Monitoring
This phase involved 12 months of post-fieldwork monitoring, during which groundwater levels were tracked monthly using dips and data logger downloads to monitor for fluctuations and potential contamination risks.
The project was divided into two key phases:
Phase 1: Ground Investigation
This phase focused on the drilling of boreholes, excavation of trial pits, and sampling of soil and water at various depths.
Phase 2: Long-term Groundwater Monitoring
This phase involved 12 months of post-fieldwork monitoring, during which groundwater levels were tracked monthly using dips and data logger downloads to monitor for fluctuations and potential contamination risks.
Approach
Approach
Our team adopted a meticulous and methodical approach to sample collection and site investigation. This included:
- Following the SOCOTEC technical procedure (GEO-TP) for sampling on PFAS sites, in conjunction with the client’s specification
- Mandatory PFAS Investigation and Sampling for PFAS Testing awareness training for all team members involved in the project
- A stringent QA/QC investigation and sampling plan to minimise the potential risk of cross-contamination, which included:
- Setting up a dedicated sampling station
- Robust decontamination procedures of drilling and sampling equipment
- Limiting the types of materials allowed in designated sampling areas, prohibiting possible PFAS-containing materials and using PFAS-free substitutes
- Dedicated wash down areas using tested potable water and PFAS-free detergents
- Using clean, sterile tools, decontaminated between boreholes, for sampling
- Implementing a strict separation between "dirty" and "clean controlled" areas during sample processing
- Storing samples in ice baths rather than using conventional ice packs, and ensuring they were dispatched to the laboratory in special containers within 24 hours to maintain sample integrity
Our team adopted a meticulous and methodical approach to sample collection and site investigation. This included:
- Following the SOCOTEC technical procedure (GEO-TP) for sampling on PFAS sites, in conjunction with the client’s specification
- Mandatory PFAS Investigation and Sampling for PFAS Testing awareness training for all team members involved in the project
- A stringent QA/QC investigation and sampling plan to minimise the potential risk of cross-contamination, which included:
- Setting up a dedicated sampling station
- Robust decontamination procedures of drilling and sampling equipment
- Limiting the types of materials allowed in designated sampling areas, prohibiting possible PFAS-containing materials and using PFAS-free substitutes
- Dedicated wash down areas using tested potable water and PFAS-free detergents
- Using clean, sterile tools, decontaminated between boreholes, for sampling
- Implementing a strict separation between "dirty" and "clean controlled" areas during sample processing
- Storing samples in ice baths rather than using conventional ice packs, and ensuring they were dispatched to the laboratory in special containers within 24 hours to maintain sample integrity
Conclusion
All site investigation and drilling works were completed on schedule without any delays, despite the more stringent processes required for PFAS sampling. Laboratory results confirmed that there were no elevated levels of PFAS in areas not previously identified as contamination hotspots, demonstrating that the procedures and decontamination protocols used by our team were effective. This ensured the data collected was accurate and representative of the overall site conditions.
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