Diesel #2 is used to heat nearly 400,000 dwellings in Virginia. Home heating oil released from leaking underground tanks located adjacent to homes and residing in unsaturated soil adjacent to houses poses a potentially serious health risk. Specifically, the migration of hazardous vapors into buildings, known as vapor intrusion, can negatively impact indoor air quality in homes and public buildings (USEPA 2015). In this look-back study, we assessed the potential for petroleum vapor intrusion by sampling soil vapor at 25 previously remediated spill sites. Residual contaminants, in particular total petroleum hydrocarbons (TPH) and naphthalene, were detected in approximately 1/3 of the samples. Concentration levels were correlated to site variables (building type, remediation time, physiographic region) including previous abatement measures. Spill category as assigned by the remediation contractor was investigated in conjunction with these three site variables. Remediation time was the most promising predictive site variable, with visible trends downward in DEQ Category 2 sites with increased remediation time. Higher contaminant concentrations were found near basement-style dwellings, which we hypothesize is due to the wall of the basement blocking horizontal migration of contaminants and the flow of oxygen to the release source zone. We found that many sites exceeded the sub-slab risk target threshold in naphthalene concentration, which has negative implications on previous abatement strategy efficacy. / Master of Science / Diesel is used to heat nearly 400,000 residences in Virginia. Diesel released from leaking underground tanks located adjacent to homes and residing in soil adjacent to houses poses a potentially serious health risk. Specifically, the migration of hazardous vapors into buildings can negatively impact indoor air quality in homes and public buildings (USEPA 2015). In this study, we assessed the potential for vapor migration by sampling soil vapor at 25 previously remediated spill sites. Residual contaminants were detected in approximately 1/3 of the samples. Concentration levels were compared to site variables (building type, time since spill, soil type) including previous remediation activity. Spill category as assigned by the remediation contractor was investigated in conjunction with these three site variables. Remediation time was the most promising as a predictive site variable. Higher contaminant concentrations were found near dwellings with basements, which we hypothesize is due to the wall of the basement blocking horizontal migration of vapors. We found that many sites exceeded the target threshold in naphthalene concentration, which has negative implications on previous remediation effectiveness.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/84395 |
| Date | 25 July 2018 |
| Creators | Weiner, Ellen Rebecca |
| Contributors | Environmental Sciences and Engineering, Widdowson, Mark A., Little, John C., Isaacman-VanWertz, Gabriel |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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