by Linda Cook, Jill Ready, PG, Steve LaRosa with Weston & Sampson

 “An ounce of prevention is worth a pound of cure.” This well-known statement by Benjamin Franklin, originally penned in the Pennsylvania Gazette in the 1730s to highlight the importance of fire prevention, holds great significance for data quality control in environmental site investigations today. As the science surrounding per- and polyfluoroalkyl substances (PFAS) has grown and evolved, so too has the importance of adequate PFAS data quality control. While the environmental and health risks of PFAS are widely discussed, cost-benefit analyses for poor versus high-quality PFAS data have received limited attention. For brownfield sites in particular, where site assessment and cleanup activities are often being completed with limited United States Environmental Protection Agency (EPA) Brownfields grant funding, data quality can deeply impact grantees’ abilities to achieve their goals for sites undergoing assessment and cleanup. This article will evaluate the total cost of quality in PFAS analyses, emphasizing the strategies necessary to generate the best data for your projects and clients.

The Cost of (Poor) Quality

In his 1956 Harvard Business Review essay “Total Quality Control,” Armand Feigenbaum introduced “The Cost of Quality” concept for industrial manufacturing businesses. The concept introduced four categories of quality-related costs: prevention, appraisal, internal failure, and external failure (Figure 1). Today, the Cost of Quality concept is applicable to PFAS testing, where poor data can lead to costly missteps and far-reaching consequences (Table 1). The costs of poor-quality PFAS data are also often unpredictable, making them impossible to anticipate, schedule, or budget.

Figure 1. Illustration of the four quality cost categories as introduced by Armand Feigenbaum in "The Cost of Quality."

Table 1: The costs of poor-quality PFAS data can be significant and far reaching and are often unpredictable.

If data are determined to be of such poor quality that they are unsuitable for their intended use, additional sampling and analysis may be required to address data gaps. In the most serious of cases, field investigations may need to be completely re-performed, resulting in a loss of previously invested resources, reducing the availability of Cooperative Agreement funds for use on other priority sites, and impacting public trust.

Inaccurate data can also lead to costly and more unnecessary and aggressive approaches for treating and managing PFAS-impacted resources. For instance, if a laboratory produces results that are consistently biased high, it may prompt remedial actions that are more extensive and expensive than required.

Financial penalties for exceeding regulatory thresholds are another potential cost consequence of inaccurate PFAS data. Inaccurate PFAS results can lead to non-compliance with regulatory PFAS standards, which may result in fines and/or enforcement actions.

Beyond financial implications, poor quality data can also impact project timelines, have social and emotional consequences, and damage brand reputations. For brownfield sites undergoing assessment and cleanup with funding provided by EPA Brownfields grants, delayed project timelines can result in projects not being completed before the end of the grant performance period, necessitating the use of funds for grant extension requests that may or may not be approved.

Why PFAS Testing Is So Challenging

PFAS testing involves specialty analytical methods that are particularly difficult to perform accurately for several reasons, including their ubiquitous presence, regulatory requirements, method complexity, and a growing selection of ancillary methods. In particular, the common presence of PFAS in lab equipment, field supplies, and consumer products increases the potential for cross-contamination during both sample collection and analysis. Testing methods demand ultra-low detection limits (often in the parts-per-trillion range), advanced instrumentation, and rigorous controls. Not all labs are up to the task, yet many have rushed to meet surging demand without the experience or infrastructure to deliver reliable results.

Complicating matters further, standard methods only detect a fraction of the estimated 10,000+ PFAS compounds. Newer techniques like Total Oxidizable Precursors Assay (TOPA), Adsorbable Organic Fluorine (AOF), and Extractable Organofluorine (EOF) attempt to estimate total PFAS content, but vary in accuracy, comparability, and validation. Without standardized reporting protocols, reviewing data from different labs becomes both time consuming and error prone.

Building a Foundation of Quality

Investing in high quality data saves money, reduces risk, and improves outcomes. A robust PFAS sampling and testing program aimed at generating high-quality data involves two core strategies: prevention and assessment.

Prevention Strategies:

• Define Objectives Early: Align project teams, regulators, and labs on compounds of concern, detection limits, and intended data use.
• Use Qualified Labs: Vet your proposed laboratories carefully for PFAS-specific experience. Avoid selecting based on lowest price alone.
• Develop a detailed Site-Specific Quality Assurance Project Plan (QAPP): The QAPP should address PFAS-specific requirements and outline Data Quality Objectives.
• Train Sampling Teams: Use PFAS-free materials and emphasize the importance of documentation and adherence to protocols.
• Implement a Quality Management System: Oversee and maintain data quality throughout any sampling and analysis program, evaluating for areas of improvement and ensuring data integrity.
• Include Quality Control Samples: Standard reference materials and blind quality control samples help track laboratory performance and catch anomalies early.

Assessment Strategies:

• Field Oversight: Document and review field practices to ensure adherence to protocols.
• Laboratory Oversight: Review laboratory protocols and practices to monitor performance.
• Data Review: Perform independent data validation and usability assessments throughout the project to evaluate data reliability. Incorporate reviews of comprehensive data packages including all supporting documentation and raw data (known as a Level 4 data report). This review will ensure that data used for project decisions are accurate, complete, and defensible.

For Brownfield Sites, Data Quality Is Non-Negotiable

Brownfield sites often have complex histories and liability considerations. Introducing unreliable PFAS data to brownfield site assessment and cleanup projects can lead to financial, legal, and environmental consequences for environmental professionals, grantees, municipalities, and the public. However, investing in high-quality data can simplify decision-making, reduce risks, and improve project outcomes.

While rigorous testing and oversight may increase upfront costs, those expenses are far less than the cost of poor-quality data. As the demand for PFAS testing grows and regulatory standards evolve, robust approaches to data quality will be increasingly necessary.

For brownfield sites with limited time and funding for assessment and cleanup, high-quality PFAS data are invaluable, enabling informed decisions, improving stakeholder confidence, and helping maximize the use of grant funds. Investing in prevention and rigorous quality assessment from day one is the surest way to protect people, budgets, and reputations.

(A longer version of this article was originally published in the June 2025 issue of the Journal of the New England Water Works Association, Inc.)

The Authors:

by James P. Cinelli, P.E., P.G., BCEE, Liberty Environmental

Vapor intrusion is a growing concern in environmental health, specifically in highly developed urban areas where soil gases or contaminated groundwater can migrate into buildings. Vapor intrusion occurs when volatile organic compounds (VOCs) and other harmful contaminants seep through cracks or other openings in a building’s foundation and it can potentially pose significant health risks to occupants. To combat this issue, Sub-Slab Depressurization Systems (SSDS) have emerged as an effective solution.

Understanding Vapor Intrusion

Vapor intrusion occurs when hazardous vapors from contaminated groundwater or soil migrate into indoor spaces. This typically takes place through small cracks and other openings in the foundation of a building. There are significant health risks posed to occupants of a building who experience long-term exposure to these contaminants ranging from respiratory issues to more severe conditions, including cancer.

What are Sub-Slab Depressurization Systems?

Sub-Slab Depressurization Systems are an engineered solution designed to reduce indoor vapor concentrations. These systems create a vacuum beneath a building’s foundation, drawing vapors away from the sub-slab area and preventing their entry into the indoor environment. The primary components of an SSDS (Sub-Slab Depressurization System) include:

1. Suction Points: These are pits or perforated pipes installed beneath a building’s slab foundation that collect vapors.

2. A Fan: Air circulation from a fan or blower creates negative pressure (depressurization) beneath a slab foundation.

3. Vent Stack: This directs collected vapors beneath a foundation safely outside and away from windows and air intakes to ensure they do not re-enter a building.

Implementation Process

The implementation of an SSDS begins with a thorough site assessment to identify the source and concentration of contaminants. Engineers can then design a tailored SSDS system to address specific building and site conditions. Once designed, installation typically brings minimal disruption, as it can often be completed without significant alterations to an existing structure.

After installation, an SSDS system does require regular monitoring and maintenance to ensure its effectiveness. This includes inspecting suction points for blockages, checking the fan for operation, and conducting air quality tests to verify that vapor concentrations remain at safe levels.

Liberty Environmental’s talented team of remediation experts has proven experience addressing vapor intrusion and assisting in the process of integrating sub-slab depressurization systems. Contact us at info@libertyenviro.com to schedule a site assessment or speak with a member of our team to learn more.  

The Author:

James P. Cinelli is an environmental engineer and the president of Liberty Environmental, Inc., an environmental consulting firm which he co-founded in 2004. The company has 35 employees with offices in Philadelphia, Lancaster, PA, Reading, PA, New York City, and Lebanon, NJ. The company’s clients include local, regional and international companies, and include banks, real estate developers, oil & gas companies, and large manufacturing firms.

by Vincent Carbone, Senior Geologist, HDR, Inc.

Over the years, the redevelopment of brownfields has matured. In fact, in some cases the process of acquiring funding, characterizing sites, remediating and finally redeveloping them has become somewhat routine.  For those fortunate enough to have received funding from federal or state agencies and through economic incentives, redevelopment has been a success.  In most cases, these communities had the ability and organization to assist them in the planning, development, and rehabilitation of properties.  With the assistance of economic development corporations and supportive communities willing to develop their most pressing redevelopment needs, the properties were easy to prioritize and redevelop.  

Now more than ever the need is fixed on those communities that do not have the means or the expertise to manage a portfolio of smaller properties impacting a community.  Perhaps the issue is a highway corridor providing entrance into a key demographic or community.  Perhaps it is an old commercial strip mall that fronts an old industrial complex. For certain it’s not the 1,500 acres of Bethlehem Steel or any one of that prime brownfield’s redevelopment successes, but rather a project with a diverse demographic with little or no vision as how to go about redevelopment from an economic, environmental, or power perspective.  

The Need for a Playbook

It’s time to move to another level of maturity, to make brownfield redevelopment accessible to this less equipped type of community.  But they need help. They need vision. They need a Brownfields Redevelopment Playbook, which provides a holistic summary of the three key factors that make for successful property community redevelopment: Economics, Power/ Infrastructure, and Environmental Stewardship.  This is the first step to helping communities with limited resources prioritize their diverse and unique blend of many properties into a workable vision and plan.  

Economics

Economics is the lifeblood of community redevelopment, but what types of business are appropriate for the community? Will the community demographics be better suited for one industry or another?  What are the current and future economic trends for the locality or region?  What investments should be made to support those trends?  The playbook should provide a framework of the economic drivers for the community and provide both short-term, mid and long-term goals for revitalization to meet those needs.      What industry “fits” with the community that will bring benefits and job creation to the locality and region.  

Power and Infrastructure

With redevelopment comes the need for infrastructure upgrades and efficiency to support new industry or just an aging utility network.  With the development of data centers and battery energy storage facilities, the need for power, water and infrastructure (water, sewer, natural gas, fiberoptics/broadband and power) is immense and poses several questions.  Can the power and utility infrastructure of the community support the proposed redevelopment?  What types of power generation are available for that area?  Is the water supply or wastewater treatment sufficient to address the proposed redevelopment? Can renewable energy supplement in design the more traditional forms of generation?  Short term, mid and long-term needs reflect the economic incentives.  The Playbook can identify infrastructure needs to support proposed economic development and attract business, provide renewable energy resources to the region, and can be integrated with redevelopment on brownfields that have limited options to redevelopment. 

Environmental

Environmental stewardship is the protection of human health and the environment. But it also encompasses the risk and enhancement of natural features such as wetlands or other sensitive habitats.  It also includes a community’s culture and providing enough green and recreational space for the community to enjoy the redevelopment and to enhance the life of occupants of the area.  Together with the economics section, the playbook can identify federal and state brownfields or economic development funds that can be pursued to make the vision a reality.  The playbook should also feature timelines for redevelopment, which can help set realistic goals and demonstrate phased approaches to redevelopment and community engagement.    

Comprehensive and Considerate

Looking at each of the elements individually – economics, power/infrastructure, and environmental—and holistically, playbooks can provide a Highest and Best Use (HABU) or what is considered the best fit for the community.  The Playbook can be used to support grant funding, community outreach, help plan for infrastructure upgrades and goes a long way toward demonstrating a comprehensive and considerate evaluation of improvement in brownfield redevelopment.  

The Author:

Vincent “Vinny” Carbone is a Professional Associate and Senior Geologist with HDR Engineering.  Vinny has been performing brownfields redevelopment services for over 33 years.  During his career he has brought his redevelopment experience to multiple market sectors including transportation, water, architecture, and power redevelopment. Working in HDR’s Bethlehem PA office, he has been redeveloping Bethlehem Steel, and the Lehigh Valley for over 25 years.  He currently is working on several playbooks supporting redevelopment of former coal power plants and former nuclear facilities including several industrial properties across the country.  He is experienced in property redevelopment with USEPA Brownfields grants and is and has been a Qualified Environmental Professional for several Cleanup Grants and Revolving Loan Funds.

by Liberty Environmental

Redeveloping former industrial sites for residential use requires careful evaluation of vapor intrusion risks. There is a risk that volatile organic compounds (VOCs) were released into the subsurface at sites where dry cleaners were located, gas stations were operating, or where other industrial activity previously occurred. These prior uses pose significant potential health risks to future residents. Additionally, properties adjacent to sites that were once gas stations or utilized for industrial purposes may be impacted by migration of vapors from these sources, necessitating a thorough investigation before redevelopment.

What is Vapor Intrusion & How Can it Be Detected?

Vapor intrusion occurs when VOCs migrate from contaminated soil or groundwater into indoor air spaces. This pathway can expose residents to harmful chemicals, making it critical for redevelopers to perform due diligence. A comprehensive environmental site assessment should be conducted prior to any redevelopment to identify potential sources of contamination, including investigation into historical land use and neighboring properties with known releases. When a vapor intrusion risk is identified, sampling and analysis of soil gas and indoor air is performed to confirm the presence or absence of a vapor intrusion condition.

How Is Vapor Intrusion Mitigated?

If vapor intrusion is suspected, a detailed evaluation plan should be implemented. This includes soil gas sampling and indoor air testing to assess the extent of vapor migration. Based on the findings, appropriate mitigation strategies must be incorporated into the redevelopment design. These may include vapor barriers, sub-slab depressurization systems, and enhanced ventilation to prevent VOCs from entering living spaces.

State regulatory agencies provide guidance and oversight for vapor intrusion assessments and mitigation. Engaging environmental professionals and coordinating with state agencies ensures compliance and protects public health.

Why is Addressing Vapor Intrusion Important?

Addressing vapor intrusion is a vital component of residential redevelopment on or near former industrial sites. Proactive evaluation and mitigation not only safeguard future occupants but also facilitate successful and sustainable redevelopment projects.

Liberty Environmental’s talented team of professional engineers, geologists and licensed remediation professionals have proven experience testing for VOCs and implementing remediation for redevelopment projects. Contact us at info@libertyenviro.com to schedule a site assessment or speak with a member of our team to learn more.  

by Joel Kane, Sr Associate, Fleming Lee Shue

Advancements in in-situ remediation technologies have enabled practitioners to aggressively target even the most persistent environmental contaminants. However, it is critical for environmental professionals to recognize that these technologies may unintentionally alter subsurface geochemistry and mobilize or concentrate non-target compounds. This phenomenon—referred to as Technologically Enhanced Contamination—can present unforeseen challenges during long-term monitoring, site closure, and waste management.

TENORM

One of the clearest examples of this phenomenon involves the concentration of Naturally Occurring Radioactive Materials (NORM)—such as isotopes of uranium, thorium, and radium—which are present in trace amounts in soil and groundwater. When groundwater is extracted and treated in large volumes, trace levels of NORM can accumulate in scale deposits, filter media, and sludge within treatment systems. Over time, these accumulations may exceed background levels and surpass regulatory thresholds, transitioning into Technologically Enhanced Naturally Occurring Radioactive Material (TENORM)¹.

This process is well-documented in oil and gas operations, where radium-rich scale forms during initial crude separation. Similarly, coal—a common carrier of radioactive isotopes—can produce TENORM when combusted, with radionuclides concentrating in the resulting coal ash. When such ash is later used as fill material, as historically was the case in much of New York City, a remedial system (such as a pump-and-treat well or recovery trench) can unintentionally accumulate TENORM within filters and piping.² 

Although certainly not a concern at every site, properties with specific risk factors — such as historic coal ash fill or long-term groundwater extraction systems — may benefit from evaluation of potential TENORM accumulation within treatment infrastructure.  Monitoring of scale, filters, and sediments, and proper waste characterization prior to disposal, may be important steps for mitigating radiological health and safety risks. 

ERH and Secondary Contaminant Mobilization

The combined use of Electric Resistance Heating (ERH) and Soil Vapor Extraction (SVE) can significantly enhance the removal of volatile and semi-volatile organic compounds. ERH increases subsurface temperatures, volatilizing contaminants and improving mass transfer to the vapor phase, where they are captured by SVE systems.

However, superheating the subsurface can also inadvertently increase the mobility of otherwise immobile contaminants—such as Polychlorinated Biphenyls (PCBs). Though PCBs have low volatility under ambient conditions, elevated temperatures enhance their partitioning to the vapor phase.³  When combined with the strong advective forces of an SVE system, low-level PCB concentrations can migrate toward extraction points, and potentially concentrate in knock-out drums, vapor treatment vessels, and even within localized areas of the subsurface if not fully extracted by the SVE.

Several studies and post-operation evaluations have identified unexpectedly high PCB concentrations in vapor-phase effluent and condensate, requiring specialized waste handling and disposal.⁴  While ERH remains a powerful tool, practitioners must anticipate the possibility of mobilizing compounds not originally targeted in the remedial design.

ISCO and Metal Mobilization

In Situ Chemical Oxidation (ISCO) is another widely used remedial technology, wherein strong oxidants—such as sodium persulfate, permanganate—are injected into the subsurface to destroy organic contaminants.

However, these oxidants can often significantly alter the geochemical balance of the aquifer. They may lower pH, increase redox potential, and raise ionic strength—conditions that favor the dissolution of naturally occurring metals previously bound to soil minerals. Following ISCO treatment, it is not uncommon to observe elevated concentrations of iron, manganese, arsenic, and lead within the groundwater monitoring programs.⁵ 

Though these metals are not typically the focus of remediation, their mobilization can complicate site closure or regulatory compliance, particularly if they were previously below detection limits. For sites considering ISCO, baseline groundwater chemistry should be evaluated in advance, and post-treatment monitoring should include metals to assess for geochemically driven mobilization.

ERH-Induced Geochemical Shifts and Metals

In addition to contaminant volatilization, ERH can cause broader geochemical shifts within the local affected aquifer. When highly chlorinated solvents—such as PCE or TCE—are thermally degraded, the reaction often generates free chloride ions, which can acidify the groundwater and increase its ionic strength.⁶

This shift enhances the solubility of subsurface metals, which may then appear in monitoring data as elevated concentrations of iron, manganese, arsenic, or lead. While often transient, these metals spikes can delay regulatory closure or complicate long-term monitoring, especially when concentrations exceed site-specific cleanup criteria.

As with ISCO, pre-treatment geochemical profiling and careful interpretation of post-treatment data are critical for managing unintended consequences.

Implications for Remedial Design and Site Management Monitoring

Modern remedial technologies offer powerful tools to achieve cleanup goals, but it is important to be aware that they may also trigger secondary effects that are not immediately apparent during remedy design. Subsurface heating, oxidation, and even pump & treat can all change the behavior of metals, radionuclides, and semi-volatile organics in ways that can influence both short and long-term outcomes.

To help best anticipate and manage Technologically Enhanced Contamination, environmental professionals may opt to:

• Conduct thorough baseline investigations of groundwater chemistry and geologic conditions
• Develop a robust conceptual site model that considers geochemical responses
• Monitor non-target compounds throughout and after system operation
• Coordinate with regulators early to plan for temporary and/or unexpected byproducts or secondary contaminant mobilization/spikes.

Understanding these site-specific interactions is critical for managing costs, ensuring regulatory compliance, and achieving sustainable site closure.

1. U.S. EPA (2022). TENORM in Oil and Gas Production. https://www.epa.gov/radiation/tenorm-oil-and-gas-production-wastes
2. NYC Department of Environmental Protection. Historical Fill and Ash Use in NYC.
3. Johnson, G. et al. (2009). PCB Behavior in Subsurface Thermal Remediation. Environmental Science & Technology.
4. Heron, G., Van Zutphen, M., & Carroll, S. (2009). “Design and performance of an in situ thermal remediation at a former manufacturing facility.” Remediation Journal, 19(3), 5–21. Rogers, R.D., et al. (1999). “Application of electric resistance heating to PCB-contaminated soils.” Journal of Hazardous Materials, 68(3), 235–256.
5. Interstate Technology & Regulatory Council (2005). In Situ Chemical Oxidation Guidance Document.
6. Lee, T.Y., et al. (2015). Impact of Thermal Remediation on Groundwater Geochemistry. Environmental Science: Processes & Impacts.

The Author:

Joel Kane is a Senior Associate at Fleming Lee Shue, where he oversees the firm’s technical operations and manages a diverse portfolio of remediation projects across the greater New York Metropolitan Area. He specializes in complex remediation sites and his experience spans both the public and private sectors. Joel works closely with developers, agencies, real estate firms, and legal teams to navigate environmental regulations across local, state, and federal programs—including NEPA, CERCLA, the Brownfield Cleanup Program, E-Designations, petroleum spills, and CEQR/SEQR.

By Michelle Onofrio, National PFAS Technical Manager, ALS USA Environmental

Per- and polyfluoroalkyl substances (PFAS) are hazardous compounds that have been used heavily in manufacturing since the 1950s. While their usefulness is derived from their chemical structure, the strong carbon-fluorine (C-F) bonds present in these compounds render them resistant to degradation. PFAS are well-known to be persistent and ubiquitous in the environment and have been found in environmental samples around the globe, but the distribution and concentrations of these contaminants vary across the USA.

The wide array of brownfield redevelopment sites presents a multitude of potential contamination sources. When considering the potential for high levels of PFAS contamination, it is important to consider the history of land use at a particular site and the site’s proximity to certain areas. In this article, we discuss how to consider historical land use to anticipate whether PFAS are likely to be contaminants of concern.

Manufacturing and chemical sites

Obvious sources of PFAS contamination include manufacturing facilities that developed PFAS or used PFAS heavily in manufacturing processes. Industrial use of PFAS is highly concentrated in the Northeastern USA, especially along the I-95 corridor.

Regions with historical manufacturing of chemicals, paints and coatings, urethane and foam, textiles and carpeting, paper and food packaging, plastics and resins, metal plating, and other industrial processes are likely to contain high levels of PFAS in the surrounding environment.

Manufacturing processes that typically do not involve PFAS are less likely to have PFAS contamination as a major concern. These include bricks and ceramics manufacturing, lumber milling and woodworking, blacksmithing and metal forging, and glassmaking.

The age of a manufacturing facility can also be an indicator of whether PFAS contamination is present; areas that were only used for manufacturing before the 1950s are unlikely to pose a risk for PFAS contamination.

Airports and firefighting training areas

Aqueous film-forming foam (AFFF) is used to combat specific fires, including aviation fires. AFFF typically contains very high concentrations of PFAS, so airports and firefighting training locations may be source locations for significant PFAS contamination. Until recently, AFFF was typically not treated as hazardous waste after use.

Instead, it was generally washed away with water, introducing high concentrations of PFAS to soil, groundwater or surface water in the surrounding environment. AFFF storage tanks and systems may still contain PFAS, even if the systems are no longer in use.

Municipal and industrial waste landfills

Before health risks associated with PFAS were known, PFAS were used in many common household items including nonstick cookware, food packaging materials, personal care products, cleaning products, electronics, and clothing and carpeting manufactured to be water-resistant, stain-resistant and/or fire-resistant.

Once discarded, these items introduce PFAS into municipal landfills. Landfills that have accepted industrial waste from PFAS-heavy manufacturing facilities are also likely to contain increased concentrations of PFAS.

Wastewater treatment plants and land-applied sewage sludge and biosolids

Sewage sludge refers to untreated residual material produced by wastewater treatment plants, while biosolids indicate a sludge that has received some level of treatment. Sewage sludge and biosolids have been used for land applications since the early 1900s. The standards for wastewater treatment established by the Clean Water Act in 1972 resulted in an increase in the generation of biosolids, and subsequently land application throughout the country.

Sewage sludge treatment does not specifically target PFAS, so even treated biosolids can contain these contaminants. Wastewater treatment plant discharge and land-applied biosolids, especially if produced near highly contaminated areas, are likely sources of PFAS contamination in the environment.

Analytical considerations for highly contaminated sites

Samples originating from the areas described may contain PFAS at concentrations of orders of magnitude higher than other typical samples. When considering a laboratory partner for analysis of these types of samples, it is beneficial to ensure the laboratory employs mitigation strategies to overcome the challenges of processing high-concentration PFAS samples.

Communication throughout the course of your site testing and analysis project is crucial; it is encouraged to discuss site history with your project manager, and you should expect timely updates regarding any challenges that may arise.

High-quality data and rapid turnaround times are achievable with these types of projects, especially when using a laboratory experienced in analyzing highly contaminated samples for PFAS.

The Author:

Michelle Onofrio is the National PFAS Technical Manager for ALS USA Environmental. Michelle provides technical support on workflow optimization and new method development, prioritizing quality and consistent, reliable service. Michelle works closely with the company's PFAS laboratories throughout the country in New York, New Jersey, Pennsylvania, Michigan, Texas, and Washington.

By Bill Allgeier, Laboratory Manager, ALS USA Environmental

When it comes to monitoring Volatile Organic Compounds (VOCs) at brownfield sites, especially those in remote or power-limited locations, passive air sampling offers an accessible, reliable option. Unlike active sampling—which requires power sources and calibrated pumps—passive techniques rely on diffusion to collect samples over time. 

These low-maintenance approaches are growing in popularity across site remediation, health and safety, and fenceline monitoring projects. This article covers the different passive VOC sampling tools available, their strengths, and how to choose the right one for your site.

Cost Effective, Field-Friendly

Passive air sampling collects airborne contaminants without pumps or powered devices. Instead, compounds are captured as they naturally diffuse through the air and into the sampling media. It’s a cost-effective and field-friendly method, ideal for long-duration monitoring or projects where access is limited. Common applications include indoor air testing, ambient outdoor air, personal exposure monitoring, and soil vapor investigations.

Passive VOC Sampling Tools

There are four key passive sampling options for VOCs. Each tool fits different field conditions, project goals, and regulatory contexts.

• Silonite Canisters are ideal for “whole air” sampling. The canisters are filled over 24 hours using a flow regulator – they require no pump and allow for analysis of 60+ VOCs. Additional methods like reduced sulfur compounds and fixed gases can be analyzed from the same canister, removing the need to deploy multiple sampling techniques. They're highly versatile and suitable for indoor, outdoor, and soil vapor applications.
• Passive TD Tubes are used for long-term sampling (up to 14 days, depending on the compound), especially for low-level VOC monitoring. They're small, rugged, and comply with EPA Method 325. Great for fenceline, LDAR, and indoor use. However, typically they have a limited number of analytes that can be reported. 
• VOC Badges are the go-to option for personal exposure monitoring. Workers wear the badge for up to 8 hours to assess individual VOC exposure levels. These are compliant with occupational health standards.
• Radiello Samplers are flexible samplers with a 7-day deployment window, ideal for industrial or mining sites. They measure up to 31 VOCs and can also support non-VOC testing (e.g., formaldehyde, NO2).

Need to ship your samples fast? Canisters and TD tubes don’t require refrigeration and ship easily with commercial couriers.

Choosing the Right Tool for the Job

Selecting the best method depends on your project objectives, site conditions, and regulatory requirements. Consider:

• •Sampling duration – Canisters (any duration up to 7 days), TD tubes (up to 14 days, depending on the compound), badges (8 hours), and Radiello (7 days).
• Target VOCs – Do you need a wide panel (e.g., over 60 compounds)? Go with canisters. Need a focused list? Badges or TD tubes may suffice.
• Sampling environment – For personal exposure, use VOC badges. For soil vapor, ambient air or industrial zones, canisters or TD tubes work better.
• Accreditation needs – For example, ALS provides NELAP & AIHA accreditation for methods using canisters and TD tubes, ensuring data meets defensibility standards.

Why Passive Sampling Works Well for Brownfield Sites

Passive sampling is often the best fit for brownfield redevelopment projects because it’s simple, scalable, and doesn’t require power or bulky equipment. It can support key project stages, including baseline air quality assessments, post-remediation verification, and long-term monitoring. And since these methods are non-intrusive, they’re ideal in community-sensitive areas.

Whether you’re assessing indoor air, monitoring an industrial fenceline, or verifying cleanup at a brownfield site, passive VOC sampling is a proven and practical approach that ensures your sampling campaign is efficient, accurate, and compliant.

The Author:

Bill Allgeier is Laboratory Manager of the ALS USA Environmental full-service laboratory in Rochester, NY.  Bill has been with the ALS environmental team for 26 years as an Analyst, Operations Manager and Lab Manager, and oversees a 24,000 sq ft. facility where the team processes over 290,000 air, soil, water, drinking water and waste sample tests annually.   Email: bill.allgeier@alsgobal.com

by Christopher D. Valligny, LSRP, Montrose Environmental

Embreeville Park in West Bradford Township, Pennsylvania, is a testament to what’s possible when environmental remediation, historical stewardship, and community planning converge. Once home to a psychiatric hospital complex dating back to the 19th century—and later, a brownfield marked by contamination and deteriorating infrastructure—the 200-acre property has been reimagined into preserved open space through a collaborative effort grounded in sustainable redevelopment.

In 2019, facing a proposal for more than 1,100 residential units, residents rallied to chart a new course for the site. With community backing, the Township acquired the property for $22.5 million, halting the proposed high-density development and committing to the site's long-term ecological and historical value.

Tackling Environmental Liability with Strategic Funding and Compliance

Redeveloping a property of this scale—and complexity—demanded not just public support but also a robust financial and technical roadmap. Montrose’s brownfield experts helped secure a $1.5 million grant through the Land and Water Conservation Fund and assembled a layered funding portfolio with state and local partners. That financing enabled critical assessment, remediation, and early redevelopment work.

Milestones included:

1. Phase I & II ESAs to characterize environmental conditions and target contamination.
2. Act 2 Program compliance, resulting in a Release of Liability and setting the legal foundation for future recreational reuse.
3. Hazardous and universal waste removal, paired with geotechnical efforts that allowed on-site demolition debris to be safely reused for land stabilization.

Historic Preservation and Community Cohesion

The park’s transformation wasn’t limited to environmental cleanup. Guided by archaeologists, the project protected Native American cultural resources—preserving local heritage while restoring the land’s public utility. As of 2024, 185 acres have been designated for passive recreation and conservation. Planned improvements include walking trails, ball fields, and interpretive signage to showcase both natural and cultural history.

Lessons for the Northeast Brownfield Community

Embreeville Park offers replicable insights for BCONE members and other Northeast stakeholders:

1. Community-Driven Outcomes: The pivot away from dense redevelopment exemplifies how public input can shift brownfield narratives toward long-term, non-commercial value.
2. Creative Reuse: On-site material recovery for stabilization cut costs and reduced waste—an essential approach for municipalities with limited redevelopment budgets.
3. Integrated Partnerships: Success hinged on tight collaboration between municipal leaders, environmental consultants, legal experts, and funding agencies.

The Author:

Christopher D. Valligny, LSRP, Senior Scientist II, Montrose Environmental Chris is a Senior Scientist with over 15 years of experience in environmental consulting, ecological research, and policy implementation. Licensed as a NJDEP Licensed Site Remediation Professional and UST Closure/Subsurface Evaluator, he also holds OSHA 40-Hour HAZWOPER certification. Chris manages complex brownfield investigation and remediation projects—including Phase I/II Environmental Site Assessments—throughout New Jersey, Pennsylvania, and Delaware. His interdisciplinary approach supports a diverse client base of insurers, municipalities, developers, nonprofits, and legal teams.

by Abraham Cullom, PhD, Pace® Director of Water Safety & Management

The Author:

Abraham Cullom, Ph.D., Director of Water Safety and Management, Pace® Building Sciences  Dr. Cullom is the Director of Water Safety and Management at Pace®. He holds a B.S. from the University of Pittsburgh and a Ph.D. from Virginia Tech in Civil and Environmental Engineering, where he published multiple peer-reviewed papers demonstrating the impact of in-building plumbing environments on important opportunistic pathogens, antibiotic resistance, and microbial ecology. A cross-disciplinary expert, Dr. Cullom translates insights from engineering, microbiology, and chemistry into practical solutions to mitigate disease risks in water systems and help end Legionnaire’s disease.

By Matthew J. Gozdor, Quantitative Hydrogeologist/Senior Technical Specialist at GZA GeoEnvironmental, Inc.

With artificial intelligence (AI), scientists and engineers are faced with a familiar question: The tools are impressive on their own, but how do we use them to provide effective, reproducible results? Our recent work for a client to develop a groundwater model that was as accurate as traditional modeling but with fewer data points and lower cost helps illustrate the way forward.

For this project, we focused on machine learning (ML), which is a subset of AI. ML uses algorithms and statistical models to analyze data for patterns, draw inferences from those patterns, and learn from the patterns without being issued explicit instructions. In this instance, we needed to demonstrate to regulators that impacted groundwater was discharging to a nearby stream and not flowing underneath the stream.  

Traditional modeling to meet our objective required obtaining a significant amount of information through complex field work and gathering historical information, LIDAR data, geological data, etc. The information needs for our ML model were significantly less and limited to weather information from a nearby weather station, river elevation data, and groundwater levels. Our AI-assisted model used Python, a common programming language popular in the ML community, and an open source “package” named Pastas developed for groundwater scientists and engineers to analyze hydrogeological time series. Pastas uses a transfer function noise model to show how the groundwater system will respond to a  stressor (e.g., precipitation) while also incorporating random noise on the output to better reflect the complexity of a hydrogeological system. 

To test the model, we used it to predict future groundwater elevations which were compared to actual measured values over time. Using the Normalized Root Mean Square Error (NRMSE), which compares the predicted values against the observed values while normalizing them by the standard deviation of the observed data, we found that our ML model’s values came within 2% of real-world observations.

Our approach has the potential to be used in a wide range of groundwater scenarios, from estimating snowmelt effects to controlling groundwater in tunneling operations. Core to going forward, however, will be ensuring that the model reflects the real-world data, and that the data reflects the risks: In other words, trust, but verify. 

Scientists and clients are understandably concerned about how to use these tools and where they fit into our work. By developing ML models that can be checked against real-world results, and carefully choosing what data a model is built on, clients and contractors alike can make better-informed decisions, while saving time and money.

The Author:

Matthew J. Gozdor is a Quantitative Hydrogeologist and a Senior Technical Specialist at GZA GeoEnvironmental, Inc. With 25 years of experience, his focus is on groundwater flow modeling, fate & transport modeling, aquifer testing design and evaluation, and hydrologic evaluations. www.gza.com, matthew.gozdor@gza.com