Where There is Exposure, There is a Problem: Identifying Exposure Pathways

It may seem like the objective of every project is to completely wipe out contamination, but it’s a little more nuanced than that. Sure, we want to make certain that a client’s property is as clean as it can be for future use, but it’s also important to consider where actual risks to human health occur in situations where a thorough site cleanup isn’t possible. That’s why, when we develop a Conceptual Site Model (CSM) a key component is the identification of potential exposure pathways and receptors. Once we can prove there’s no possible way a human can come in contact with the contaminant, we’re one step closer to obtaining the coveted “No Further Action” letter from the regulatory body with which we’re working.

It all starts with the investigation. In short, we use the data collected from soil and groundwater tests to delineate and characterize the horizontal and vertical nature of the contamination plume. The size, shape, and location gives us a general idea of which structures and buildings may be impacted, and, using this information, we can draw up our CSM.

In the Conceptual Site Model (seen in the simplified figure below) you can see we’ve labeled the actual dry cleaner machine (the established source of contamination) the buildings resting above the contaminated soil and groundwater, the different types of impacted soils,  groundwater and all identified migration pathways.  The contaminant migration pathways are indicated by the arrows in our figure.

Conceptual Site Model Example

The next step is to test those pathways to determine if there’s a potential for exposure, because where there’s exposure, there’s a problem.  We start at the established source, and work our way down and up from there, checking surrounding structures for possible vapor intrusions, and testing soil and groundwater impacts and the possible receptors they could come in contact with (sewer laterals, sewer mains, groundwater wells, and the like.)

Once we’ve determined the existing pathways, it’s time to figure out what (if anything) needs to be done. We conduct an exposure assessment based on the type of receptors being impacted. Those receptors can be humans, utility corridors, drinking water wells, and the like. As an environmental consultant, we want to wipe out any contamination, but we are also beholden to both the institutional constraints and the client’s legal obligations. Identifying the potential exposure pathways at a Site can help us pin-point our focus as we draw up our site closure strategy.



Thermal Remediation: How to put VOCs on the Hot Seat

We know that chlorinated solvents tend to volatize on their own, so what happens if we use the chemical’s physical properties to cause them to volatilize even more? That’s the concept behind Thermal Conductive Heating (TCH) or Electric Resistance Heating (ERH). The idea is to heat the subsurface to such a temperature that any present contaminant becomes volatized and can be removed from the soil and groundwater. Using super-heated metal rods (TCH) or an electric current (ERH) along with some familiar applications from remedial techniques we’ve touched on in the past, a “thermal” approach can make for an effective remediation strategy for sites where other techniques are less feasible.

Excavation might not be an option if above ground structures are in the way or if contamination is too deep. Soil Vapor Extraction Systems (SVE) can prove to be an effective solution, but can prove to be equally ineffective if the contaminant plume is too deep or the concentration of the contaminant is too great. In other cases, the contamination could be resting in a patch of more dense clay soil, making it more difficult to extract contaminants. Contamination in saturated clay soil can be slowly released into groundwater over time in a process known as “back diffusion,” which makes it more difficult to achieve cleanup goals. In all these scenarios, TCH or ERH can be a viable option.

Thermal Conductive Heating
Figure Courtesy of: Terratherm













A thermal remediation system has a set of components that, working together, can effectively remove contamination from a cleanup site. The first component is the heat itself. In a TCH application, several heating rods are placed into the impacted areas to effectively raise the temperature of the ground. Additionally, a vacuum component will be installed into these wells to extract the vapor generated by the heat. If necessary, groundwater extraction wells will be installed near the heating wells to collect impacted groundwater. Treatment systems are used to remove contaminants from the water and vapor that has been extracted.

Once the thermal remediation process is started, the components operate like workers on an assembly line. Heat is applied to the subsurface, chemicals become volatized, and contamination is collected in the vapor phase by the vacuums in the heating wells. The vapors are put through a treatment component, then released into the atmosphere.  Groundwater is extracted from the subsurface as well and goes through a treatment process of its own.

“Thermal” applications are considered “in-situ”, or in-place, and are perfect for sites in which demolition or excavation are not possible, or the contamination cannot be addressed by any other means.

Bloomberg: Struggles Persist to Enhance Vapor Data Innovations

Reproduced with permission from Daily Report for Executives, 153 DER (Aug. 9, 2016). Copyright 2016 by The Bureau of National Affairs, Inc. (800-372-1033) <http://www.bna.com>

Public and regulatory concerns are steadily rising over the risk of health detriments linked to vapor intrusion that seeps into the floors of buildings.

The Environmental Protection Agency continues to warn short-term exposure to trichloroethylene (TCE), a degreaser and primary contaminant spread through vapor intrusion, among pregnant mothers may cause fetal cardiac defects.

And the agency is moving forward with nearly surefire finalization of a rule to add vapor intrusion, the process of volatile compounds migrating through sub-surface groundwater or soil to air in above-ground structures, to the Superfund Hazard Ranking System.

But high-tech developers and vendors are struggling to overcome hurdles in vapor intrusion sensor development, leaving potentially affected communities in the lurch with unreliable or inaccessible data.

Mobile technology isn’t yet sophisticated enough to detect contaminants at necessary precision, even with the historical help of some government agencies, according to recent Bloomberg BNA interviews with consultants and advocates.

That’s leaving vapor intrusion assessment at a deficit. Sensor technology is advancing at breakneck speed in other regulatory areas prone to hazard, such as occupational safety and health and climate change.


Need for Improvement

The EPA nationwide and private industry rely on largely passive sampling of air, groundwater, soil and sub-slabs to model the likely threat posed by a vapor intrusion pathway, the agency says.

That approach traditionally involves canister sampling with gas chromatography/mass spectrometry analysis and other methods to assess indoor air concentrations of common vapor intrusion contaminants, such as TCE and tetrachloroethene (PCE), as well as benzene, toluene, ethylbenzene and xylenes, a chemical group known as BTEX.

Those technologies and tactics, however, fail to effectively diagnose short-term risks, contamination spikes and variability, because they target time-weighted averages, rather than continuous monitoring, experts told Bloomberg BNA.

“There’s a lot of evidence that indoor air concentrations vary enormously, daily, seasonally and by weather. Soil/gas concentrations may also vary seasonally,” Lenny Siegel, executive director of the Center for Public Environmental Oversight, told Bloomberg BNA.

Traditional devices passively sample over the course of 24 hours to several weeks.


Health Concerns

Concerns over contaminants, coupled with a lack of trusted analysis, has even led to the closure of schools nationwide after EPA Region 9 released Superfund guidance in 2014 to highlight the need to safeguard pregnant mothers from TCE exposure.

The guidance points to conclusions outlined in a 2011 EPA toxicity assessment held in a compendium called the Integrated Risk Information System.

“This and other findings in the IRIS assessment of TCE indicates that women in the first trimester of pregnancy are one of the most sensitive populations to TCE inhalation exposure,” the guidance said. “For fetal cardiac malformations, a specific developmental effect, the critical period for exposure is considered to be the approximate 3-week period in the first trimester of pregnancy during which the heart develops.”


Public Disruptions

The Magnolia Elementary School in El Cajon, Calif., which is part of EPA Region 9, shut down for the 2015-2016 school year due to perceived vapor intrusion risks.

A class action lawsuit pointed to a TCE plume in the vicinity brought on by a former aerospace manufacturing plant.

Local school officials took similar action in recent months in Winston Salem, N.C. and Millis, Mass.

States such as New York, Connecticut and Massachusetts also have moved forward with their own revisions to TCE and other contaminant concentration standards, and state agencies have shut down sites due to excessive contamination.

Moreover, the Massachusetts Department of Environmental Protection is likely to dive into revisitation needs for roughly 200 sites already closed after remediation of TCE contamination, agency officials announced in April.

The state’s 2011 revised standards slashed appropriate toxicity levels for residential indoor air TCE exposure more than 14 times, from 85 micrograms per cubic meter (µg/m3) to 6 µg/m3.


‘No Consensus’ Exists


Interested parties continue to debate, however, the TCE exposure linkage with cardiac birth defects.

“There’s no consensus on this [TCE] issue. You put 10 scientists in a room, it’s five and five. It’s like Republicans and Democrats; its split down the middle,” Blayne Hartman, vapor intrusion expert with Hartman Environmental Geoscience, told Bloomberg BNA.

The Silicon Valley Leadership Group contested the guidance in 2015, arguing industry is shouldering drastically increased compliance costs despite the region’s failure to properly roll out the policy change.

The EPA, however, rejected that complaint.

“There are no significant uncertainties that have arisen since 2011 that were not considered prior to the release of EPA’s final toxicity assessment as to whether TCE causes fetal heart defects,” Region 9 Superfund Director Enrique Manzanilla told the group in November 2015.

Meanwhile, the EPA’s 2015 release of national vapor intrusion guidance already pushes site managers and risk assessors to consider sub-surface hazards.



Emerging Technology

A handful of developers are spearheading sensor innovation and other technology tied to vapor intrusion assessment.

The challenge is to deploy user-friendly, continuous monitoring, mobile devices with parts per billion precision at prices around $1,000 each.

A Palo Alto, Calif., startup named Entanglement Technologies is one potential vendor pushing the envelope.

The company’s lead product, dubbed the Autonomous Rugged Optical Multigas Analyzer, is a mobile, rapid response device.

“It can be costly to screen large areas to determine when that [vapor intrusion] pathway is important, to what degree it’s a concern to health and to be able to cheaply and efficiently either determine that mitigation is required or to determine that mitigation is not required,” Tony Miller, Entanglement chief executive officer, told Bloomberg BNA. “Our instrument allows you to quickly determine where it is important to measure so you can get that study done more quickly, and when it’s done more quickly, it’s done more cheaply because a significant fraction of costs is associated with labor.”

The product, however, isn’t yet on the market. Miller predicted he’d start selling the device in 2017.



Fusion Technology Being Deployed

Another trailblazer already deployed nationwide is a fusion of a traditional gas chromatography instrument with more precise, customized data intake capacity and analysis, created by Hartman and Mark Kram, founder and chief technology officer at Groundswell Technologies.

“I firmly believe that continuous monitoring, regardless of whether it’s with a sensor or an analytical system, is the only way to be able to understand appropriate dynamics and risks and then respond in a timely fashion,” Kram told Bloomberg BNA. “That in and of itself would allow me to confidently classify this as the most innovative option out there.”

The Hartman-Kram device, which costs roughly $35,000-$60,000 each, is similar in size to a small suitcase.

Other groups like the North Carolina-based RTI International are moving forward with their own products.



Agency Assistance/Marketability

The Entanglement product received development funding from the National Science Foundation and the National Institutes of Health.

Entanglement’s Miller said enhancement is the only thing keeping his product off the market.

“We have a set of technologies which are fundamentally new, and there has been time required to develop the technology. It hasn’t been a market force issue,” he told Bloomberg BNA. “We’re now at the point where we have successfully demonstrated these technologies, so now it’s just making the transition to commercialization.”

Despite Miller’s 2017 pledge, some experts say developers as a whole are at least a half dozen years away from marketing a product en masse.

But other agencies don’t seem to be weighing in with real resources despite the apparent risks at play.



EPA Unaware of Assistance

The EPA’s Office of Research and Development said it is unaware of any ongoing research development or private sector assistance for vapor intrusion.

The National Aeronautics and Space Administration (NASA), an agency involved heavily in sensor innovation, also isn’t sponsoring or developing environmental contamination innovation, a spokesman said.

The National Institute of Standards and Technology and the Environmental Security Technology Certification Program, an agency that has traditionally funded vapor intrusion assessment research, didn’t respond to Bloomberg BNA requests for comment.

But other experts questioned whether a lack of demand is restraining innovation.

“What we have is a chicken and egg problem,” the Center for Public Environmental Oversight’s Siegel said. “The regulators don’t require these technologies because they aren’t quite on the market yet, and the companies aren’t pushing, at least, the portable ones; they’re reluctant to develop them because there’s no requirement for them.”

On top of that, the possibility remains that the EPA may reverse its cardiac defect guidance, Hartman said.

“That may take away the demand, or [threshold standards] might go up enough that maybe some of these sensors can get low enough.

That’s all speculation,” he said.



Superfund Connection?



The EPA’s looming finalization of the rule (RIN:2050-AG67) to add vapor intrusion to the Hazard Ranking System under Comprehensive Environmental Response, Compensation and Liability Act, better known as Superfund, is generating more interest in and concern for sub-surface hazards.

And while the EPA Region 9 TCE guidance is the most potent precipitator, the Superfund listing may in part drive the push for technological innovation, the experts said.

“This [regulatory development] is not likely to be the last one. With each additional incremental step in the regulation and highlighting of the exposure pathway, you’re going to see more and more developments in the science and technology,” Jeff Carnahan, a vapor intrusion expert with EnviroForensics, an environmental engineering company that represents dry cleaners, told Bloomberg BNA.

Technological improvements may actually, however, unveil a smaller risk posed by sub-surface contaminants, Siegel said.



Source of Contamination

“If [the source of contamination] turns out to be a can of gun cleaner, than you know where it’s coming from. If it’s a crack in the floor, you know where it’s coming from,” he said, referring to household items that may emit contamination. “This is actually a major issue at a lot of sites where they find something but they don’t know whether it’s really vapor intrusion.”

The rulemaking doesn’t call for revisitation of current Superfund sites or those proposed and deleted.

A decision to include revisitation mandates would have been a game-changer for innovation demand though, Kram said.

“The regulators have to adopt a balanced position, as they do not want to unnecessarily burden the regulated community with high compliance costs,” he said. “Their current policies indicate that they are convinced that acute TCE exposures of low concentrations can be harmful. In addition, they acknowledge that conditions are dynamic. This creates a significant challenge regarding the methods they are currently accepting for acute TCE related risk characterization.”

EnviroForensics Attending MWDLA Annual Convention This Weekend

It’s been a whirlwind couple of days at EnviroForensics. In the midst of the major move from our current headquarters to our new one, we’re also getting ready for one of the biggest weekends of the year, the annual Midwest Drycleaning and Laundry Association Convention!!

Over the next two days, dozens omidwestdrycleaningf drycleaners from Indiana, Kentucky and Ohio will converge on the Belterra Casino Resort and Spa in Florence, Indiana, to talk about new technologies and emerging challenges in the industry. But, of course it won’t just be strictly for business.

We’re excited to meet up with our partners and friends in the industry who have played a major role in our 20 year existence. Environmental consulting is very much, at its core, a people business. We’re brought in to clean up contamination that can threaten human health, but we’re also there to provide a safety net to the business owner, who likely never knew of the potential for pollution.

Some of these drycleaners have been our clients, but we also consider them our friends. This weekend we’ll be hitting the golf course with them, catching up over a few drinks at happy hour, and talking shop while dining on some delicious food.  We take pride in our customer service, and it’s events like these that give us a better understanding of the drycleaner experience and help us cultivate a more personal connection with our clients. If you’re heading down to Florence today, we’ll see you there!


U.S. District Court Adds to Kiger Progeny

In a recent legal decision that reinforces existing case law in Indiana, Judge Jon E. DeGuilio of the U.S. District Court for the Northern District of Indiana (Hammond Division) ruled in favor of a policy holder in an environmental contamination coverage dispute.

Old Republic Insurance Company v. Gary/Chicago International Airport Authority (No. 2:15-CV-281-JD) saw Old Republic seeking declaratory relief and reimbursement from the Airport Authority for defense costs expended in defending the Airport Authority against IDEM’s claims for investigation and cleanup of fifty-two separate different contaminants.

Old Republic argued that its non-specific pollution exclusion (which read “This policy does not cover claims directly or indirectly occasioned by, happening through or in consequence of:…(b) pollution and contamination of any kind whatsoever,” was distinguishable from language Indiana courts had previously identified as ambiguous (under Indiana law, which interprets insurance contracts as it would any other, ambiguity in coverage exclusions must be interpreted in a way that finds for coverage).

Although different than the absolute pollution exclusion by means of excluding “pollution” and “contamination” rather than the language found in American States v. Kiger 662 N.E.2d 945 (Ind. 1996) and its progeny, “pollutants and contaminants,” the district court was not convinced that the minor modification of the language was sufficient to overcome the Indiana Supreme Court’s approach. In the view of the Indiana Supreme Court, in the event that an insurer wishes to exclude coverage, it must specifically exclude the substances for which it would negate coverage; a moderate change of broad exclusionary language is insufficient to resolve the ambiguity Kiger and its progeny identified and held against its drafters.

Although Indiana is unique in the stringency of its courts’ identification of ambiguity in commercial general liability insurance contracts, this most recent decision simply adds another layer to the stratifying case law requiring insurance contracts to specifically identify hazards against which they will not insure.