Simultaneous Monitoring of Volatile Organic Contaminant Concentration and Controlling Factors for Vapor Intrusion Risk Evaluations—Two Select Cases
Kram, M. L., B. Hartman, and C. Frescura, 2022. “Simultaneous Monitoring of Volatile Organic Contaminant Concentration and Controlling Factors for Vapor Intrusion Risk Evaluations—Two Select Cases”. Remediation, v.32, issue 4, p.259-272; https://onlinelibrary.wiley.com/doi/10.1002/rem.21728
Dr. Kram and colleagues describe two unique deployments of innovative continuous monitoring. One of these cases involved a "mystery" site where more than 3 years of investigation using traditional sampling approaches could not resolve critical questions. Within a few days all remaining questions were answered.
Long Short-Term Memory Neural Network (LSTM-NN) for Aquifer Level Time Series Forecasting Using in-Situ Piezometric Observations
Solgi, Ryan, Hugo Loaiciga and Mark Kram, 2021. Long Short-Term Memory Neural Network (LSTM-NN) for Aquifer Level Time Series Forecasting Using in-Situ Piezometric Observations, Water Resources Research, https://www.sciencedirect.com/science/article/pii/S0022169421008507?via%3Dihub
This article by Solgi, Loaiciga and Kram describe a methods to predict groundwater levels with exceptional accuracy using machine learning. This will be incorporated into key web based software platforms to rapidly determine available water supplies.
Vapor Intrusion Risk Evaluation Using Automated Continuous Chemical and Physical Parameter MonitoringKram, M. L., B. Hartman, C. Frescura, P. Negrao, and D. Egelton, 2020.“Vapor Intrusion Risk Evaluation Using Automated Continuous Chemical and Physical Parameter Monitoring”, Remediation, v.30, p.65-74; https://onlinelibrary.wiley.com/doi/abs/10.1002/rem.21646
Dr. Kram and colleagues demonstrate how continuous vapor intrusion monitoring (chemistry and physical parameters) can be used to evaluate risk. In fact, this approach can help derive a more accurate risk assessment, as results more closely meet EPA decision criteria than traditional randomly timed methods. In addition, beginning the sampling event just a few hours after the peak of a vapor intrusion “event” (as documented by multiple lines of evidence) can yield dramatically different conclusions and mitigation recommendations. As such, this clearly shows how traditional randomly timed indoor sample data can be called into question.
Helping Lenders Resolve the Vapor Intrusion Pathway Within Days
Hartman, B., M. Kram, and C. Frescura, 2019. Helping Lenders Resolve the Vapor Intrusion Pathway Within Days, Environmental Bankers Association Newsletter, January, 2019, p.16-17.
Dr. Hartman and colleagues describe how vapor intrusion challenges can be quickly resolved using automated continuous monitoring and web based tracking. This approach is rapidly gaining acclaim and attention within the lending and Brownfields market sectors, as time becomes critical in order to expedite real property and loan transactions.
Automated Continuous Monitoring and Response to Toxic Subsurface Vapors Entering Overlying Buildings—Selected Observations, Implications and Considerations
Kram, M. L., B. Hartman, and N. Clite, 2019. “Automated Continuous Monitoring and Response to Toxic Subsurface Vapors Entering Overlying Buildings – Selected Observations, Implications and Considerations”, Remediation, v.29, p.31–38, https://doi.org/10.1002/rem.21605 ; https://onlinelibrary.wiley.com/doi/abs/10.1002/rem.21605
Dr. Kram and colleagues describe multiple recent deployments of automated continuous vapor intrusion monitoring and response at various facilities as well as lessons learned and future considerations. The approach generates data patterns that allow practitioners to rapidly resolve critical questions regarding whether vapor intrusion is occurring, whether an indoor source exists, location of vapor entry points and indoor sources, optimization of mitigation systems, and control of fugitive emissions during aggressive remediation (e.g., thermal applications). Once controlling factors such as differential pressure, barometric pressure fluctuations and ventilation impacts are understood, responses can be tailored to address specific requirements with surgical spatial and temporal precision. Given that more dramatic pressure fluctuations are anticipated with climate change, it seems reasonable to assume that natural controlling factors could result in greater pressure differential across foundations and therefore result in greater mass flux.
High-Frequency Continuous Monitoring to Track Vapor Intrusion Resulting From Naturally Occurring Pressure Dynamics
Hosangadi, V., B. Hartman, M. Pound, M. Kram, C. Frescura, B. Shavers, 2017. High Frequency Continuous Monitoring To Track Vapor Intrusion Resulting From Naturally Occurring Pressure Dynamics, Remediation, Spring, v.27, no.2, p.9-25, doi:10.1002/rem.21505; http://onlinelibrary.wiley.com/doi/10.1002/rem.21505/full
Dr. Kram and distinguished colleagues employed automated continuous vapor intrusion monitoring at a facility in the coastal region and documented a temporal correlation between increases in indoor TCE concentration and diurnal fluctuations in barometric pressure and pressure differential. This correlation was observed with a predictable daily frequency even for very slight diurnal changes in barometric pressure and associated pressure differentials measured between subslab and indoor regimes. These observations suggest that advective vapor transport and intrusion can result in elevated indoor TCE concentrations well above risk levels even with low-to-modest pressure differentials. This indicates that vapor intrusion can occur in response to diurnal pressure dynamics in coastal regions and suggests that similar natural phenomenon may control vapor intrusion dynamics in other regions exhibiting similar pressure, geochemical, hydrogeologic, and climatic conditions.
Cost Comparison: Continuous Automated Vapor Intrusion Monitoring vs. Passive Sampling Approaches
Kram, M. L., Hartman, B. and Frescura, C. (2016), Vapor Intrusion Monitoring Method Cost Comparisons: Automated Continuous Analytical Versus Discrete Time-Integrated Passive Approaches. Remediation, 26: 41–52. doi:10.1002/rem.21482.[http://onlinelibrary.wiley.com/doi/10.1002/rem.21482/abstract?campaign=woletoc]
Dr. Kram and distinguished colleagues (Dr. Blayne Hartman and Cliff Frescura) derived a cost comparison between continuous automated vapor intrusion monitoring and passive sampling approaches. The authors have gained considerable experience deploying continuous monitoring systems and have documented that continuous monitoring costs are competitive with currently accepted passive sampling approaches. Continuous monitoring also allows for immediate and automated response to acute TCE risks before exposures have exceeded a duration of concern.
Kram, Mark L., 2015. The Emperor's Old Clothes: An Inconvenient Truth About Currently Accepted Vapor Intrusion Assessment Methods, Guest Editorial, Ground Water Monitoring and Remediation, Fall 2015, v.35, issue 4, DOI: 10.1111/gwmr.12140. [http://onlinelibrary.wiley.com/doi/10.1111/gwmr.12140/full]
This invited guest editorial points to the fact that since contaminant vapor concentrations can be dynamic both indoors and in the subsurface, currently accepted vapor intrusion assessment and monitoring methods can yield false negative and false positive conclusions. The implications are significant, as these accepted practices can result in flawed decisions regarding hazardous exposure and explosion risks. This is particularly relevant when acute exposures and explosion risks are of concern. The article also discusses newly commercialized cost-effective methodologies that are far more accurate, raises key questions about claims currently included in national standards and guidance, and encourages industry leaders to support the critical evaluation of these claims using state-of-the-science methodologies and empirical approaches. Perhaps most importantly, Dr. Kram issues a plea to regulatory leaders to immediately consider and adopt more appropriate methodologies for acute vapor intrusion risk assessment, monitoring and response.
Dynamic Subsurface Explosive Vapor Concentrations
Kram, Mark L., Peter M. Morris and Lorne G. Everett, 2011. Dynamic Subsurface Explosive Vapor Concentrations: Observations and Implications, Remediation Journal, Winter 2011, v.22, issue 1, p.59-69. [http://onlinelibrary.wiley.com/doi/10.1002/rem.21299/abstract]
In this seminal article, Dr. Kram documents some of the earliest evidence that vapor intrusion risks can be dynamic, and that they can fluctuate in response to changes in barometric pressure. The project summarizes efforts to continuously monitor sensors tracking methane, oxygen and atmospheric pressure in the shallow subsurface overlying a petroleum extraction area where two homes had previously exploded. Implications for vapor intrusion (including both petroleum based and chlorinated volatile constituents) and hydraulic fracturing operations are profound, and suggest that worst case risk scenarios can be determined through continuous monitoring over multiple barometric cycles. In addition, Dr. Kram and his colleagues point out that soil vapor surveys are commonly performed during elevated barometric pressures due to preferable weather conditions, and that this is precisely when harmful soil vapor concentrations are depressed. As such, false negative results are possible. Furthermore, during dropping barometric pressure conditions (e.g., an approaching storm), deeper seated toxic compounds can migrate to the surface, thereby posing the highest risks.
Continuous Soil Gas Measurements: Worst Case Risk Parameters
Kram, Mark L., Peter M. Morris and Lorne G. Everett, 2013. Dynamic Subsurface Explosive Vapor Concentrations: Observations and Implications, in Continuous Soil Gas Measurements: Worst Case Risk Parameters, Eds. Everett and Kram, ASTM International Special Technical Publication #1570, p.20-31. [http://www.astm.org/DIGITAL_LIBRARY/STP/SOURCE_PAGES/STP1570.htm]
Following the attention garnered from the 2011 article (above), Dr. Kram and Dr. Everett were invited to co-Chair an international symposium to address worst case risk parameters associated with vapor intrusion, the factors that can control dynamics, and emerging technologies to best characterize and address vapor intrusion risks. This book represents a compilation of key presentations from that historic symposium. The Kram et. al. (2011) vapor intrusion article was reproduced for inclusion in this important publication. The publication also summarizes key recommendations delivered to more than 100 regulators throughout the globe, where they are encouraged to adopt new strategies to more effectively determine and reduce risks using state-of-the-art technologies. This publication is having a profound impact on standards and policies related to vapor intrusion.
Web-Based Automated Remediation Performance Monitoring
Kram, Mark L., Steve Airhart, Daniel Tyler, Amy Dindal, Andrew Barton, John L. McKernan, and Gregg Gustafson, 2011. Web-Based Automated Remediation Performance Monitoring and Visualization of Contaminant Mass Flux and Discharge, Remediation Journal, Summer 2011, v.21, issue 3, p.89-101. [http://onlinelibrary.wiley.com/doi/10.1002/rem.20291/abstract]
In this groundbreaking article, Dr. Kram describes how he and his colleagues from DOE, EPA, USDA and private sector implemented several automated web-based continuous monitoring systems to track remediation performance in real-time using Dr. Kram's innovative inventions. The approach described has the potential to save the government and private sector tremendous amounts of time and money while also providing services that are far more accurate than conventional methods. It is for these types of inventions that Dr. Kram soon thereafter received the National Ground Water Association's prestigious Technology Award.