Total petroleum hydrocarbon (TPH) is a mixture of various oil substances composed of alkane, alkene, cycloalkane, and aromatic hydrocarbons (benzene, toluene, ethylbenzene, xylene, etc.). In this study, we investigated 92 groundwater wells around 36 gas stations to evaluate distribution characteristics of petroleum hydrocarbons. Groundwater in the wells was sampled and monitored twice a year. The fraction analysis method of TPH was developed based on TNRCC 1006. The test results indicated aliphatic and aromatic fractions accounted for 28.6 and 73.8%, respectively. The detection frequencies of TPH in the monitoring wells ranged in 21.6 - 24.2%. The average concentration of TPH was 0.11 mg/L with the concentration range of 0.25~0.99 mg/L. In the result of TPH fraction analysis, in aliphatic fractions were 19% (C6-C8 : 0.2%, C8-C10 : 0.4%, C10-C12 : 0.4%, C12-C16 : 0.5%, C16-C22 : 1.0%, C22-C36 : 16.6%), and aromatic fractions were 81% (C6-C8 : 1.1%, C8-C10 : 0%, C10-C12 : 2.9%, C12-C16 : 0.3%, C16-C22 : 4%, C22-C36 : 66.8%). Fractions of C22-C36 were detected in about 83% of the monitoring wells, suggesting non-degradable characteristics of hydrocarbons with high carbon content.
Keywords: Fractionation;Groundwater;Monitoring;TPH;