Characteristics of Volatile Organic Compounds in the Atmosphere at the Surrounding Area of an Oil-Contaminated Remediation Site

[[abstract]]This study aims to investigate the characteristics of atmospheric volatile organic compounds (VOCs) emitted from an oil-contaminated remediation site. A sampling network including five sampling sites located at the surrounding area of the oil-contaminated remediation site and nearby community was established for sampling VOCs near ground level. In this study, VOCs were collected by carbontrap 300 packed multi-bed sampling tubes from February 2002 to April 2003. The tubes were then desorbed by a thermal desorption unit (TDU) and then analyzed by a gas chromatography with a flame ionization detector (GC/FID). In addition, methane and non-methane hydrocarbons (NMHC) were automatically monitored in-situ and correlated with the concentration of VOCs. Results from field measurements showed that the concentration of NMHC at the upwind of oil-contaminated remediation site was generally lower than the downwind site at nearby community. Major VOCs observed in the atmosphere were n-octane, toluene, and m,p-xylene. The mass ratios of toluene to benzene (T/B) were similar to the tail pipe exhaust gas’s T/B of 2.0-2.3. Similar trend was observed for the mass ratio of benzene, toluene, ethylbenzene, and m,p-xylene (BTEX). The results suggested that the atmospheric VOCs at the surrounding area of the oil-contaminated remediation site was mainly emitted from automobiles on the highway rather than from soil gas emitted from oil-contaminated remediation site. Health risk assessment indicated that the cancer risk criteria ranged from 1.1x10-9 to 7.8x10-8, while the non-cancer hazard indexes ranged from 8.4x10-5 to 3.7x10-3. Both cancer and non-cancer hazard risks did not violate the regulation of 1.0x10-6 and unity, respectively