A case study of using isotopic signatures of multiple contaminants to identify source relevance

Poster Presentation

Prepared by H. Hsu1, I. Chen2, Y. Weng3
1 - Industrial Technology and Research Institute, 321 Kuang Fu Rd. Sec. 2, Hsinchu City, Taiwan, 300, Taiwan
2 - Environmental Protection Administration, Executive Yuan, No. 83, Zhonghua Rd. Sec. 1, Zhongzheng District, Taipei, 10042, Taiwan
3 - Environmental Analysis Laboratory, Environmental Protection Administration, Executive Yuan, No. 260, Minzu Rd. Sec. 3, Zhongli District, Taouyan, 32024, Taiwan

Contact Information: hlhsu@itri.org.tw; 886921285110


Chlorinated organic solvents were popular industrial solvents. When groundwater detects pollution, it is a challenge to locate liability when there are multiple potential polluters. This occurs very often in Taiwan since factories usually clustered in the designated industrial areas.

The presented case study here is a polluted area of about 250 acres covering an industrial area and its downstream area where also existed many factories. Multiple plumes containing more than ten chlorinated organic compounds were detected above the regulated levels in the groundwater. One chemical manufacturer has been identified as one source, but it was not clear whether there exist other sources.

To resolve the source relevance issue, compound-specific isotope ratios of carbon and chlorine were analyzed for several contaminants. Interpretation of the isotopic signatures was based on the degradation potential of the compound. Long term monitoring of the water table and the geological strata were also studied to provide insight of the pollution migration. The multiple lines of evidence showed that in a certain downstream area the pollution might have come from the chemical manufacturer while there shall exist other pollution sources responsible for the rest of the area.