Identification of Chlorinated Solvent Sources in the Indoor Air of Private Residences around Hill Air Force Base, Utah
Volatile chlorinated solvents such as trichloroethylene (TCE), 1,2 dichloroethane (1,2 DCA), and perchloroethylene (PCE) have been identified in the indoor air of residences located near Hill Air Force Base (AFB), Utah. These vapors can originate from either volatilization of contaminates from shallow contaminated groundwater and transport into residences or from sources within the residence. The focus of the thesis was the development of a testing strategy for determining sources of TCE, 1,2 DCA, and PCE in the indoor air of residences near Hill AFB. Eight residences were selected for this study by Hill AFB based on prior detections of TCE, 1,2 DCA, and PCE in indoor air. Residents were asked to turn off the heating, ventilation, and air conditioning (HVAC) system and keep windows and doors closed for at least 3 hours prior to the sampling visit to reduce mixing of residence air. Indoor air samples were collected on TenaxÂ© sorbent tubes from various locations within the residences to determine the location of the potential source(s). Sampling tubes were analyzed by thermal desorption gas chromatography/mass spectrometry (GC/MS). Results from a tracer experiment using sulfur hexafluoride gas confirmed the effectiveness of sampling approach. In cases where elevated levels of chlorinated solvents were found, the suspected source materials(s) were removed and the room air was re-sampled. If removal of the materials reduced or eliminated indoor air contamination, an emission chamber was used to determine contaminant emission from the materials. Sources were identified in three of the sampled residences. Sampling in two of the residences was discontinued due to scheduling problems. Sources were not located in the remaining residences. The emission of contaminants from items identified as sources in two of the residences was measured using an emission chamber developed for this project. An ornament from residence U8-8452 emitted 36.4 ng/min/cm2 of 1,2 DCA. The emission of 1,2 DCA from a wedding dress located at residence U8-8211 was below the method detection limit of 1.99 pg/min/cm2 but the emission of PCE was 18.9 ng/min/cm2 and decreased by a factor of 7 during repeated measurements.
School:Utah State University
School Location:USA - Utah
Source Type:Master's Thesis
Keywords:1 2 dichloromethane emission perchloroethylene trichloroethylene vapor intrusion
Date of Publication:12/01/2008