This research project has been divided into four parts. The first part aims to establish methodologies for examining soil gases, simulating gasoline and gasoline vapor leakage into the soil to differentiate the source of the soil gas. Subsequently, these techniques are used to analyze real-site samples. We have completed four sets of simulated experiments, analyzed actual samples, and identified sources at seven real sites. The second part involves screening sites contaminated by gasoline, where we collect soil, groundwater, or oil samples to perform identification analysis to improve weathered gasoline identification techniques. We have collected samples from three different gasoline-contaminated sites, and the forensic analysis of these samples has been completed. The third part involves evaluating the suitability of the gasoline and diesel fingerprint database through performing regular identification test for two major domestic suppliers. We collected 50 fresh gasoline and 16 diesel samples from gas stations for identification analyses. Most samples can be accurately identified using the methods established in the preliminary project. However, some of the recent diesel products from the southern refinery of CPC Corporation, Taiwan and 95 unleaded gasoline products from Formosa Petrochemical Corporation did not match the profiles in our database. The fourth part involves hosting a conference to promote the application and results of the contamination source identification technique in Taiwan. The conference took place on October 19, 2023.

Soil gas, Environmental forensics, Fresh gasoline, GC/IRMS, Chemical fingerprint chromatogram, Diagnostic ratio, Diesel