1
|
Gschwend P, MacFarlane J, Jensen D, Soo J, Saparbaiuly G, Borrelli R, Vago F, Oldani A, Zaninetta L, Verginelli I, Baciocchi R. In Situ Equilibrium Polyethylene Passive Sampling of Soil Gas VOC Concentrations: Modeling, Parameter Determinations, and Laboratory Testing. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:7810-7819. [PMID: 35537062 DOI: 10.1021/acs.est.1c07045] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The use of low-density polyethylene (PE) sheets as equilibrium passive soil gas samplers to quantify volatile organic compounds (VOCs) such as benzene, toluene, ethylbenzene, and xylenes, and chlorinated solvents (e.g., trichloroethene and tetrachloroethene) in unsaturated subsurface environments was evaluated via modeling and benchtop testing. Two methods were devised to quantify such VOCs in PE. Key chemical properties, including PE-water (KPEw) and PE-air (KPEa) partition coefficients and diffusivities in the PE (Dpe), were determined. These KPEw, KPEa, and Dpe values were consistent with extrapolations of data based on larger compounds. Using these parameter values, field equilibration times of less than 1 day were estimated for such VOCs when using 70-100 μm thick PE sheets. Further, benchtop batch tests carried out in jars filled with VOC-contaminated soils, after 1 or 2 days, showed concentrations in soil air deduced from PE that were consistent with concentrations deduced by analyzing either water or headspace gases recovered from the same tests. Thus, PE-based measurements may overcome inaccuracies from using total soil concentrations and equilibrium partitioning models that may overestimate vapor phase concentrations up to 2 orders of magnitude.
Collapse
Affiliation(s)
- Philip Gschwend
- Civil and Environmental Engineering, Massachusetts Institute of Technology (MIT), 15 Vassar Street, Cambridge, Massachusetts 02139, United States
| | - John MacFarlane
- Civil and Environmental Engineering, Massachusetts Institute of Technology (MIT), 15 Vassar Street, Cambridge, Massachusetts 02139, United States
| | - David Jensen
- Civil and Environmental Engineering, Massachusetts Institute of Technology (MIT), 15 Vassar Street, Cambridge, Massachusetts 02139, United States
| | - Jaren Soo
- Civil and Environmental Engineering, Massachusetts Institute of Technology (MIT), 15 Vassar Street, Cambridge, Massachusetts 02139, United States
| | - Galym Saparbaiuly
- Civil and Environmental Engineering, Massachusetts Institute of Technology (MIT), 15 Vassar Street, Cambridge, Massachusetts 02139, United States
| | - Raffaella Borrelli
- CHIFIS-Novara Laboratories (CENTR), Renewable, New Energies and Material Science Research Center (DE-R&D), Eni S.p.A, Via Fauser 4, Novara 28100, Italy
| | - Fabio Vago
- CHIFIS-Novara Laboratories (CENTR), Renewable, New Energies and Material Science Research Center (DE-R&D), Eni S.p.A, Via Fauser 4, Novara 28100, Italy
| | - Alessandro Oldani
- CHIFIS-Novara Laboratories (CENTR), Renewable, New Energies and Material Science Research Center (DE-R&D), Eni S.p.A, Via Fauser 4, Novara 28100, Italy
| | | | - Iason Verginelli
- Laboratory of Environmental Engineering, Department of Civil Engineering and Computer Science Engineering, University of Rome "Tor Vergata", Via del Politecnico 1, Rome 00133, Italy
| | - Renato Baciocchi
- Laboratory of Environmental Engineering, Department of Civil Engineering and Computer Science Engineering, University of Rome "Tor Vergata", Via del Politecnico 1, Rome 00133, Italy
| |
Collapse
|
2
|
Ma J, McHugh T, Beckley L, Lahvis M, DeVaull G, Jiang L. Vapor Intrusion Investigations and Decision-Making: A Critical Review. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:7050-7069. [PMID: 32384239 DOI: 10.1021/acs.est.0c00225] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
At sites impacted by volatile organic compounds (VOCs), vapor intrusion (VI) is the pathway with the greatest potential to result in actual human exposure. Since sites with VI were first widely publicized in late 1990s, the scientific understanding of VI has evolved considerably. The VI conceptual model has been extended beyond relatively simple scenarios to include nuances, such as biological and hydrogeological factors that may limit the potential for VI and alternative pathways, such as preferential pathways and direct building contact/infiltration that may enhance VI in some cases. Regulatory guidance documents typically recommend initial concentration- or distance-based screening to evaluate whether VI may be a concern, followed by a multiple-lines-of-evidence (MLE) investigation approach for sites that do not screen out. These recommendations for detailed evaluation of VI currently focus on monitoring of VOC concentrations in groundwater, soil gas, and indoor air and can be supplemented by other lines of evidence. In this Critical Review, we summarize key elements important to VI site characterization, provide the status and current understanding, and highlight data interpretation challenges, as well as innovative tools developed to help overcome the challenges. Although there have been significant advances in the understanding of VI in the past 20 years, limitations and knowledge gaps in screening, investigation methods, and modeling approaches still exist. Potential areas for further research include improved initial screening methods that account for the site-specific role of barriers, improved understanding of preferential pathways, and systematic study of buildings and infrastructure other than single-family residences.
Collapse
Affiliation(s)
- Jie Ma
- State Key Laboratory of Heavy Oil Processing, Beijing Key Lab of Oil & Gas Pollution Control, China University of Petroleum-Beijing, Beijing 102249, China
| | - Thomas McHugh
- GSI Environmental, Houston, Texas 77098, United States
| | - Lila Beckley
- GSI Environmental, Houston, Texas 77098, United States
| | - Matthew Lahvis
- Shell Global Solutions (US), Inc., Shell Technology Center, Houston, Texas 77082, United States
| | - George DeVaull
- Shell Global Solutions (US), Inc., Shell Technology Center, Houston, Texas 77082, United States
| | - Lin Jiang
- National Engineering Research Centre of Urban Environmental Pollution Control, Beijing Municipal Research Institute of Environmental Protection, Beijing 100037, China
| |
Collapse
|
3
|
Wilson JL, Samaranayake VA, Limmer MA, Schumacher JG, Burken JG. Contaminant Gradients in Trees: Directional Tree Coring Reveals Boundaries of Soil and Soil-Gas Contamination with Potential Applications in Vapor Intrusion Assessment. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:14055-14064. [PMID: 29182871 DOI: 10.1021/acs.est.7b03466] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Contaminated sites pose ecological and human-health risks through exposure to contaminated soil and groundwater. Whereas we can readily locate, monitor, and track contaminants in groundwater, it is harder to perform these tasks in the vadose zone. In this study, tree-core samples were collected at a Superfund site to determine if the sample-collection location around a particular tree could reveal the subsurface location, or direction, of soil and soil-gas contaminant plumes. Contaminant-centroid vectors were calculated from tree-core data to reveal contaminant distributions in directional tree samples at a higher resolution, and vectors were correlated with soil-gas characterization collected using conventional methods. Results clearly demonstrated that directional tree coring around tree trunks can indicate gradients in soil and soil-gas contaminant plumes, and the strength of the correlations were directly proportionate to the magnitude of tree-core concentration gradients (spearman's coefficient of -0.61 and -0.55 in soil and tree-core gradients, respectively). Linear regression indicates agreement between the concentration-centroid vectors is significantly affected by in planta and soil concentration gradients and when concentration centroids in soil are closer to trees. Given the existing link between soil-gas and vapor intrusion, this study also indicates that directional tree coring might be applicable in vapor intrusion assessment.
Collapse
Affiliation(s)
- Jordan L Wilson
- U.S. Geological Survey, Missouri Water Science Center , 1400 Independence Road, Rolla, Missouri 65401, United States
- Department of Civil, Environmental, and Architectural Engineering, Missouri University of Science and Technology , 1201 North State Street, Rolla, Missouri 65409, United States
| | - V A Samaranayake
- Department of Mathematics and Statistics, Missouri University of Science and Technology , 1201 North State Street, Rolla, Missouri 65409, United States
| | - Matthew A Limmer
- Department of Plant and Soil Science, University of Delaware , 531 South College Avenue, Newark, Delaware 19716, United States
| | - John G Schumacher
- U.S. Geological Survey, Missouri Water Science Center , 1400 Independence Road, Rolla, Missouri 65401, United States
| | - Joel G Burken
- Department of Civil, Environmental, and Architectural Engineering, Missouri University of Science and Technology , 1201 North State Street, Rolla, Missouri 65409, United States
| |
Collapse
|
4
|
McHugh T, Loll P, Eklund B. Recent advances in vapor intrusion site investigations. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2017; 204:783-792. [PMID: 28237219 DOI: 10.1016/j.jenvman.2017.02.015] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2016] [Revised: 01/07/2017] [Accepted: 02/08/2017] [Indexed: 06/06/2023]
Abstract
Our understanding of vapor intrusion has evolved rapidly since the discovery of the first high profile vapor intrusion sites in the late 1990s and early 2000s. Research efforts and field investigations have improved our understanding of vapor intrusion processes including the role of preferential pathways and natural barriers to vapor intrusion. This review paper addresses recent developments in the regulatory framework and conceptual model for vapor intrusion. In addition, a number of innovative investigation methods are discussed.
Collapse
|
5
|
McAlary T, Groenevelt H, Seethapathy S, Sacco P, Crump D, Tuday M, Schumacher B, Hayes H, Johnson P, Górecki T. Quantitative passive soil vapor sampling for VOCs--part 2: laboratory experiments. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2014; 16:491-500. [PMID: 24513676 DOI: 10.1039/c3em00128h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Controlled laboratory experiments were conducted to demonstrate the use of passive samplers for soil vapor concentration monitoring. Five different passive samplers were studied (Radiello, SKC Ultra, Waterloo Membrane Sampler, ATD tubes and 3M OVM 3500). Ten different volatile organic compounds were used of varying classes (chlorinated ethanes, ethanes, and methanes, aliphatics and aromatics) and physical properties (vapor pressure, solubility and sorption). Samplers were exposed in randomized triplicates to concentrations of 1, 10 and 100 ppmv, with a relative humidity of ∼80%, a temperature of ∼24 °C, and a duration of 30 minutes in a chamber with a face velocity of about 5 cm min(-1). Passive samplers are more commonly used for longer sample durations (e.g., 8 hour workday) and higher face velocities (>600 cm min(-1)), so testing to verify the performance for these conditions was needed. Summa canister samples were collected and analyzed by EPA Method TO-15 to establish a baseline for comparison for all the passive samplers. Low-uptake rate varieties of four of the samplers were also tested at 10 ppmv under two conditions; with 5 cm min(-1) face velocity and stagnant conditions to assess whether low or near-zero face velocities would result in a low bias from the starvation effect. The results indicate that passive samplers can provide concentration measurements with accuracy (mostly within a factor of 2) and precision (RSD < 15%) comparable to conventional Summa canister samples and EPA Method TO-15 analysis. Some compounds are challenging for some passive samplers because of uncertainties in the uptake rates, or challenges with retention or recovery.
Collapse
Affiliation(s)
- Todd McAlary
- Geosyntec Consultants, Inc., 130 Research Lane, #2, Guelph, Ontario N1G 5G3, Canada.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
6
|
McAlary T, Groenevelt H, Nicholson P, Seethapathy S, Sacco P, Crump D, Tuday M, Hayes H, Schumacher B, Johnson P, Górecki T, Rivera-Duarte I. Quantitative passive soil vapor sampling for VOCs--part 3: field experiments. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2014; 16:501-510. [PMID: 24513784 DOI: 10.1039/c3em00653k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Volatile organic compounds (VOCs) are commonly associated with contaminated land and may pose a risk to human health via subsurface vapor intrusion to indoor air. Soil vapor sampling is commonly used to assess the nature and extent of VOC contamination, but can be complicated because of the wide range of geologic material permeability and moisture content conditions that might be encountered, the wide variety of available sampling and analysis methods, and several potential causes of bias and variability, including leaks of atmospheric air, adsorption-desorption interactions, inconsistent sampling protocols and varying levels of experience among sampling personnel. Passive sampling onto adsorbent materials has been available as an alternative to conventional whole-gas sample collection for decades, but relationships between the mass sorbed with time and the soil vapor concentration have not been quantitatively established and the relative merits of various commercially available passive samplers for soil vapor concentration measurement is unknown. This paper presents the results of field experiments using several different passive samplers under a wide range of conditions. The results show that properly designed and deployed quantitative passive soil vapor samplers can be used to measure soil vapor concentrations with accuracy and precision comparable to conventional active soil vapor sampling (relative concentrations within a factor of 2 and RSD comparable to active sampling) where the uptake rate is low enough to minimize starvation and the exposure duration is not excessive for weakly retained compounds.
Collapse
Affiliation(s)
- Todd McAlary
- Geosyntec Consultants, Inc., 130 Research Lane, #2, Guelph, N1G 5G3, Ontario, Canada.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|