4.5 Article

Compound-specific isotope analysis (CSIA) evaluation of degradation of chlorinated benzenes (CBs) and benzene in a contaminated aquifer

期刊

JOURNAL OF CONTAMINANT HYDROLOGY
卷 250, 期 -, 页码 -

出版社

ELSEVIER
DOI: 10.1016/j.jconhyd.2022.104051

关键词

Carbon isotopes; CSIA; In situ degradation; Chlorinated benzenes; Benzene

资金

  1. DuPont Canada
  2. Corteva Canada
  3. Agriscience Canada
  4. Natural Science and Engineering Research Council of Canada

向作者/读者索取更多资源

Compound-specific isotope analysis was used to investigate the natural degradation of chlorinated benzenes and benzene in a contaminated aquifer. The analysis of delta 13C values in sampling wells indicated in situ degradation of these compounds, with good correlations observed between delta 13C enrichments and decreasing groundwater concentrations. The results suggest that in situ biodegradation is the primary degradation pathway.
Compound-specific isotope analysis (CSIA) has become a valuable tool in understanding the fate of organic contaminants at field sites. However, its application to chlorinated benzenes (CBs), a group of toxic and persistent groundwater contaminants, has received less attention. This study employed CSIA to investigate the occurrence of natural degradation of various CBs and benzene in a contaminated aquifer. Despite the complexity of the study area (e.g., installation of a sheet pile barrier and the presence of a complex set of contaminants), the substantial enrichments in delta 13C values (i.e., >2 parts per thousand) for all CBs and benzene across the sampling wells indicate in situ degradation of these compounds. In particular, the 13C enrichments for 1,2,4-trichlorobenzene (1,2,4-TCB) and 1,2-dichlorobenzene (1,2-DCB) display good correlations with decreasing groundwater concentrations, consistent with the effects of in situ biodegradation. Using the Rayleigh model, the extent of degradation (EoD) is estimated to be 47-99% for 1,2-DCB, and 21-73% for 1,2,4-TCB. The enrichments observed for the other CBs (1,4-DCB and chlorobenzene (MCB)) and benzene at the site are also suggestive of in situ biodegradation. Due to simultaneous degradation and production of 1,4-DCB (a major 1,2,4-TCB degradation product), MCB (from DCB degradation), and benzene (from MCB degradation), the estimation of EoD for these intermediate compounds is more complex but a modelling simulation supports in situ biodegradation of these daughter products. In particular, the fact that the delta 13C values of MCB and benzene (i.e., daughter products of 1,2,4-TCB) are more enriched than the original delta 13C value of their parent 1,2,4-TCB provides definitive evidence for the occurrence of in situ biodegradation of the MCB and benzene.

作者

我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。

评论

主要评分

4.5
评分不足

次要评分

新颖性
-
重要性
-
科学严谨性
-
评价这篇论文

推荐

暂无数据
暂无数据