Project: Vapor Intrusion/Indoor Air Assessment Related to Historical Dry Cleaner
Location: Hobbs, New Mexico
Project Characteristics: During a review of historical records, the New Mexico Environmental Department (NMED) identified the location as a historic dry cleaner. To address NMED concerns and assess possible exposure to vapor-forming chemicals in the building, Ensolum performed an indoor-air assessment. The earliest dry cleaners began in the early to mid-1800s and used kerosene and gasoline to clean fabrics. Use of Stoddard solvent (a petroleum hydrocarbon based solvent) began in the 1920s as a less flammable alternative to kerosene and gasoline. This eventually transitioned to the predominant use of chlorinated solvents (trichloroethene and tetrachloroethene) in the 1930s. Based on the time period of operation for the historical dry cleaner on the property, Ensolum recommended collecting an indoor air sample for analysis. This was conducted by the United States Environmental Protection Agency (EPA) Method TO-15. The analysis involved volatile constituents present in both petroleum hydrocarbon and chlorinated based dry cleaning solvents.
In addition, petroleum hydrocarbon constituents are ubiquitous in ambient air in urban, commercial, and industrial settings. This is from the presence and combustion of fuel (i.e., diesel, gasoline, etc.). Thus, an ambient air sample was also collected outside of the building. The sample assessed for background concentrations of potential contaminants of concern. Prior to collecting the air samples, Ensolum performed a building survey to assess for any preferential pathways that may exist such as cracks and/or utility corridors that penetrate through the concrete floor.
Additionally, Ensolum identified possible indoor sources of volatile organic compounds (VOCs) that may contribute to indoor air concentrations detected during sampling. Indoor air sources of VOCs can include cleaners, air fresheners, aerosols, mothballs, scented candles, insect repellants, glue, paint, etc. Ensolum removed these potential sources from the building 48 hours prior to conducting the indoor air sampling. Ensolum collected over an 8-hour period during typical business hours (i.e., 9 AM to 5 PM) and on a weekend when the building was not occupied by employees and/or the public. Laboratory analytical results were compared to NMED vapor intrusion screening levels (VISLs) for commercial/industrial receptors. Where NMED VISLs were not established, Ensolum used established EPA VISLs.
Ensolum did not detect Chlorinated solvents trichloroethene and tetrachloroethene above the laboratory practical quantitation limits (nor were the associated degradation products 1,2-dichloroethene or vinyl chloride). Several chemicals associated with petroleum hydrocarbons were detected in the sample. They were also present in the ambient air sample and all at concentrations below levels of concern. Based on the results of the assessment, vapor intrusion concerns do not appear to be present at the property. Additional data, including subsurface soil gas, soil, and/or groundwater samples, could be collected to further investigate the presence of chemicals. However, additional data is not warranted at this time.
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