Yongkang Interchange petroleum station of CPC (as named as “Yongjiao station” in short) was performed the project of Environmental Protection Administration (EPA)-"potential sources of groundwater investigation plan", it accidentally discovered the underground environment suspected by the class of vinyl chloride-containing volatile organic hydrocarbons contamination, tests found TCE (trichloroethylene, TCE), dichloroethylene (dichloroethylene, DCE) and vinyl (Vinyl chloride, VC) were exceeded more than the second category of groundwater pollution control standards. Gradually for the next few years, "the potential of groundwater pollution research project. Hence, the project of "in restricted areas of contaminated groundwater of Yongkang City, Tainan County plan" (referred to the ’10 project) was for achieving the objectives.
According the results of supplement investigations in A, B zones, contaminants in downstream were moved along groundwater. Besides the additional investigation on A and B zones, also performed additional supplementary investigation of C zone. The result showed that in the southern side, ground water flow flowed to the northern or eastern-northern-northern; when the north-east to flow to the central site C, then turned north-northeast or northeast flow. The geological composition of the surface to about 0.2 meters to 1.5 meters in depth, there is about 1 to 5 meters ranging from a continuous layer of sandy silt. Sandy silt layer was getting ticker from south to north, upon S02, it reached to the maximum thickness (about 5.5 meters) gradually decreasing to the north, to S01 when the thickness is about 1.0 meters; about 5.5 m depth below the surface there is a fairly evenly when a continuous clay layer thickness of about 1 meter; there is a fine sand layer between the sandy silt and clay, the fine sand layer was found that the area of maximum thickness of about 3.0 meters of south east of eastern Yongan Road in the C zone, then gradually decreasing to the north of the S02 is no sand layer exists. Groundwater sampling and analysis results were shown that in C zone, the compounds of concern were PCE, TCE, cis-1,2-DCE and VC. The results of waste sampling showed that no. 1426 and no. 1426-5 of Yanhang section, there were buried construction waste and exceeded soil pollution control standards and detection of TPH, over soil pollution monitoring standard of copper, chromium and lead concentrations.
In tracing the source of pollution, our team use of groundwater flow distribution, chemical concentration characteristics, pollution transport modeling and assessment methods, to get Tungnan Company in Chung Cheng Road may be one source of pollution conclusions. However, due to the dissolution of Tungnan Company in 1996, and our team can not collect any information through government agencies, therefore, our team recommended follow-up work to trace the source of pollution can refer to the United States Society for Testing and Materials (American society for testing and materials, ASTM) "E1527-phase I environmental site assessment (E1527-Phese I ESA) " for related work.
The Tainan City Government EPB plans to propose, and Yanhang section, Yungkang section no. 1324-2, 1359, 1360, 1361, 1362, 1363, 1364, 1365, 1366, 1367, 1368, 1369, 1419, 1426, 1428, 1361-1, 1362-1, 1363-1, 1364-1, 1365-1, 1366-4, 1367-4, 1393-1, 1419-1, 1419-4, 1419 - 6, 1426-10, 1426-3, 1427-1, 1427-2, 1427-3, 1427-4, 1428-1, 1428-2, 1428-3, 1428-4, 1446-1 as groundwater restrain sites.