| Title: | Incorporating the Soil Gas Gradient Method and Functional Genes to Assess the Natural Source Zone Depletion at a Petroleum-Hydrocarbon-Contaminated Site of a Purification Plant in Northwest China |
| Author(s): | Ning Z; Sheng Y; Guo C; Wang S; Yang S; Zhang M; |
| Address: | "Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences, Shijiazhuang 050061, China. Key Laboratory of Groundwater Remediation of Hebei Province & China Geological Survey, Shijiazhuang 050061, China. Center for Geomicrobiology and Biogeochemistry Research, State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China. SINOPEC Research Institute of Safety Engineering Co., Ltd., Qingdao 266000, China" |
| ISSN/ISBN: | 2075-1729 (Print) 2075-1729 (Electronic) 2075-1729 (Linking) |
| Abstract: | "An increasing number of studies have demonstrated that natural source zone depletion (NSZD) in the vadose zone accounts for the majority (90%~99%) of the natural attenuation of light non-aqueous phase liquid (LNAPL). Until now, 0.05 to 12 kg/a.m(2) NSZD rates at tens of petroleum LNAPL source zones have been determined in the middle or late evolution stage of LNAPL release, in which limited volatile organic compounds (VOCs) and methane (CH(4)) were detected. NSZD rates are normally estimated by the gradient method, yet the associated functional microbial activity remains poorly investigated. Herein, the NSZD at an LNAPL-releasing site was studied using both soil gas gradient methods quantifying the O(2), CO(2), CH(4), and VOCs concentrations and molecular biology methods quantifying the abundance of the pmoA and mcrA genes. The results showed that the methanogenesis rates were around 4 to 40 kg/a.m(2). The values were greater than the rates calculated by the sum of CH(4) escaping (0.3~1.2 kg/a.m(2)) and O(2) consuming (3~13 kg/a.m(2)) or CO(2) generating rates (2~4 kg/a.m(2)), suggesting that the generated CH(4) was oxidized but not thoroughly to CO(2). The functional gene quantification also supported the indication of this process. Therefore, the NSZD rates at the site roughly equaled the methanogenesis rates (4~40 kg/a.m(2)), which were greater than most of the previously studied sites with a 90th percentile value of 4 kg/a.m(2). The study extended the current knowledge of the NSZD and has significant implications for LNAPL remediation management" |
| Keywords: | functional gene gradient method natural source zone depletion (NSZD) petroleum hydrocarbon contaminated site; |
| Notes: | "PubMed-not-MEDLINENing, Zhuo Sheng, Yizhi Guo, Caijuan Wang, Shuaiwei Yang, Shuai Zhang, Min eng 22373901D/S& T Program of Hebei/ 42007171/National Natural Science Foundation of China/ 321089, 320123, 321131./Sinopec Science Department Project/ Switzerland 2023/01/22 Life (Basel). 2022 Dec 30; 13(1):114. doi: 10.3390/life13010114" |
