| 英文摘要 |
English Abstract (short version)
EPA ROC has planed to executive 3 years environmental protecting action project since 2004, including environmental pollutant decreasing project to set up the ability of contaminant source identification, it was called environmental forensic or environmental science. There are three goals in the project: 1. Set up ability of pollutant identifies under regulation and control after weathering effect. 2. Collects representative sample from selected contaminant plume. d13C value after weathering effects were compared with reference by GC-IRMS to set up standard operation procedure of environmental forensic source identification technology for promotion domestic ability of environmental forensic technology. 3. Cooperate industry waste fingerprint database construction project, the resulting d13C value bring into database with the proper form.
The project has collected 31 CSIA literatures and reports, proved that 13C CSIA technology can identify pollution sources and evaluate the effect of natural attenuation effectively. There are 19 kinds of organic solvents and 103 solvent samples have been collected totally in this project, including 10 pollutants (dichloromethane, benzene, toluene, chlorobenzene, chloroform, trichloroethylene, tetrachloroethylene, p-dichlorobenznen, cis-1,2-dichloroethylene, 1,2-dichloroethane) under current regulation control and 54 samples totally. Use GC-IRMS to carry on 10 pollutants 13C CSIA analysis and set up standard operation procedure of d13C determination method. Use One Way ANOVA model to statistic d13C value of sample and judge the difference between samples. If p＜0.05, there is difference between two samples under 95% confidence level. Comparing two injection method：SPME(Solid Phase Micro Extraction) dip in mode and split injection mode, there is no difference between two injection methods for trichloroethylene (bp. 86.9℃) but there are difference between two injection methods for toluene (bp. 110.6℃) and tetrachloroethylene (bp. 146.5℃) under 95% confidence level. The detection limit of 6 solvents in water are 107.8mg/ml(399mV, trans-1,2-dichloroethylene), 122.8mg/ml(665mV, cis-1,2-dichloroethylene), 117.2mg/ml(360mV, 1,1,1-trichloroethane), 131mg/ml(427mV, trichloroethylene), 156mg/ml(300mV, tetrachloroethylene), 99.2mg/ml(191mV, p-dichlorobenzene) respectively.
We have collected underground water samples from monitoring wells of upstream, middle stream and downstream at RCA contaminant plume Taoyuan, Taiwan. The enriched d13C value of trichloroethylene, cis-1,2-dichloroethylene were observed on the site, the same results as simulation weathering test. We infer biodegradation on the site. Probe into the influence weathered in simulation and set up weathering method based on biodegradation and find out relationship between weathering and biodegradation by statistic method. It is proofed that 1. Dehalococcoides ethenogenes from RCA contaminant plume can dechlorinated tetrachloroethylene to their metabolites, such as trichloroethylene, cis-dichloroethylene, vinyl chloride and ethylene, quickly and completely. It will be a powerful tool of natural attenuation. 2. Enrichment factors (e) were obtained from Rayleigh-type evolution model and used as standard of tracing pollutant source.
We cooperates with NIEA industry wastes fingerprinting information database setting up project 2005 to choose 20 industry waste samples of every profession and determinate 13C value of characteristic components of sample. Set up pretreatment, detection method and identification procedures of industry wastes fingerprint. 90% 10 kinds of Different sources were identified. We selected 43 more than 80% similarity characteristic components from 35 industry waste samples from different sources after NIST database components comparison. They can divide into 6 kinds to sum up after removing the same components accord with the anticipated result. The d13C value of 20 industry waste samples, can be used to identify source from comparison d13C solvents database or other sample from same profession to narrow the source range.
This study verifies that can there is effects and is evaluated for the pollution sources and renovates in GC-IRMS 13C CSIA technology. We have to control the factors, which cause d13C value variable carefully. Because there are a lot of influence factors that can effect the environment weathers and no d13C value of the initial pollutants, it is difficult to identify pollution sources, but still can offer the information of pollutes flowing direction, understand the relationship. Propose the ability that is established of this plan in the future, cooperate with other pollution sources identification plan, offer d13C value to help the pollution source to confirm. Using GC-IRMS 13C CSIA in the final affirmation tool that the pollution sources appraised. GC-IRMS 13C CSIA might be a powerful tracing tool for monitoring contaminant groundwater flow direction and evaluating the effect of natural attenuation. We plan to study 15N , 18O CSIA to execute the project in the future and remedy the deficiency of 13C CSIA.
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