title: Vapor intrusion risk of lead scavengers 1,2-dibromoethane (EDB) and 1,2-dichloroethane (DCA).
abstract: Vapor intrusion of synthetic fuel additives represented a critical yet still neglected problem at sites impacted by petroleum fuel releases. This study used an advanced numerical model to simulate the vapor intrusion risk of lead scavengers 1,2-dibromoethane (ethylene dibromide, EDB) and 1,2-dichloroethane (DCA) under different site conditions. We found that simulated EDB and DCA indoor air concentrations can exceed USEPA screening level (4.7 × 10(-3) μg/m(3) for EDB and 1.1 × 10(-1) μg/m(3) for DCA) if the source concentration is high enough (is still within the concentration range found at leaking UST site). To evaluate the chance that vapor intrusion of EDB might exceed the USEPA screening levels for indoor air, the simulation results were compared to the distribution of EDB at leaking UST sites in the US. If there is no degradation of EDB or only abiotic degradation of EDB, from 15% to 37% of leaking UST sites might exceed the USEPA screening level. This study supports the statements made by USEPA in the Petroleum Vapor Intrusion (PVI) Guidance that the screening criteria for petroleum hydrocarbon may not provide sufficient protectiveness for fuel releases containing EDB and DCA. Based on a thorough literature review, we also compiled previous published data on the EDB and DCA groundwater source concentrations and their degradation rates. These data are valuable in evaluating EDB and DCA vapor intrusion risk. In addition, a set of refined attenuation factors based on site-specific information (e.g., soil types, source depths, and degradation rates) were provided for establishing site-specific screening criteria for EDB and DCA. Overall, this study points out that lead scavengers EDB and DCA may cause vapor intrusion problems. As more field data of EDB and DCA become available, we recommend that USEPA consider including these data in the existing PVI database and possibly revising the PVI Guidance as necessary.
authors.affiliation: State Key Laboratory of Heavy Oil Processing, Beijing Key Lab of Oil & Gas Pollution Control, China University of Petroleum-Beijing, Beijing, 102249, China. Electronic address: rubpmj@sina.com.
authors.forename: Jie
authors.initials: J
authors.lastname: Ma
authors.affiliation: State Key Laboratory of Heavy Oil Processing, Beijing Key Lab of Oil & Gas Pollution Control, China University of Petroleum-Beijing, Beijing, 102249, China.
authors.forename: Haiyan
authors.initials: H
authors.lastname: Li
authors.affiliation: Vermont Department of Environmental Conservation, Waste Management & Prevention Division, Montpelier, VT, 05620, USA.
authors.forename: Richard
authors.initials: R
authors.lastname: Spiese
authors.affiliation: Scissortail Environmental Solutions, LLC., Ada, OK, 74820, USA.
authors.forename: John
authors.initials: J
authors.lastname: Wilson
authors.affiliation: State Key Laboratory of Heavy Oil Processing, Beijing Key Lab of Oil & Gas Pollution Control, China University of Petroleum-Beijing, Beijing, 102249, China.
authors.forename: Guangxu
authors.initials: G
authors.lastname: Yan
authors.affiliation: State Key Laboratory of Heavy Oil Processing, Beijing Key Lab of Oil & Gas Pollution Control, China University of Petroleum-Beijing, Beijing, 102249, China.
authors.forename: Shaohui
authors.initials: S
authors.lastname: Guo
mesh_terms: D000332:Aerobiosis; D016902:Air Pollution, Indoor / Q000032:analysis*; D000693:Anaerobiosis; D001673:Biodegradation, Environmental; D015946:Ethylene Dibromide / Q000032:analysis*; D005025:Ethylene Dichlorides / Q000032:analysis*; D060587:Groundwater / Q000737:chemistry*; D007854:Lead / Q000032:analysis*; D008962:Models, Theoretical; D010578:Petroleum / Q000032:analysis*; D012987:Soil / Q000737:chemistry; D014835:Volatilization
chemical_list: D005025:Ethylene Dichlorides; D010578:Petroleum; D012987:Soil; D015946:Ethylene Dibromide; D007854:Lead; C024565:ethylene dichloride
keywords: 1,2-Dichloroethane; Ethylene dibromide; Fuel additives; Petroleum hydrocarbon; Vapor intrusion