Zhan Liangtong, Zhang Yihao, Wu Linbo, Zhao Runze, Zhao Li, Chen Yunmin, Lan Jiwu, Zhang Guibao
Center for Hypergravity Experiment and Interdisciplinary Research, Zhejiang University, Hangzhou 310058, China; Department of Civil Engineering, Zhejiang University, Hangzhou 310058, China; MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering, Zhejiang University, Hangzhou 310058, China.
Department of Civil Engineering, Zhejiang University, Hangzhou 310058, China.
Sci Total Environ. 2024 Oct 1;945:173654. doi: 10.1016/j.scitotenv.2024.173654. Epub 2024 Jun 6.
The investigation of leachate leakage at numerous landfill sites is urgently needed. This study presents an exploration of environmental tracing methods using δH and δC-difference in dissolved carbon (δC) to localize leachate leak points at landfill sites. δH, δC, δC, δO, and an array of physicochemical indices (e.g., total dissolved solids, temperature, and oxidation reduction potential) were monitored in both leachate and groundwater from different zones of a landfill site in China during the year of 2021-2023. Moreover, data for these parameters (i.e., the isotopic composition and physicochemical indices) from twelve published landfill cases were also collected, and these groundwater/leachate data points were located within 1 km away from the landfill boundary. Then statistical analyses, such as Pearson correlation analysis and redundancy analysis (RDA), were performed using both the detected and collected parameters at landfill sites. Consequently, the intensity of interaction between leachate and background groundwater was found to significantly control the isotopic fractionation features of hydrogen and carbon, and both the content of major contamination indicators (total dissolved solids, chemical oxygen demand, and ammoniacal nitrogen) and the oxidation reduction potential were the key impact factors. Accordingly, the water type used to indicate leachate leakage points was determined to be leachate that significantly interacted with the background groundwater or precipitation (LBGP). δH showed a perfect linear correlation (0.81 ≤ r < 1.0) with δC in leachate under highly anaerobic landfill conditions, and the δH & δC combinations in the LBGP were significantly different from those in the other water types. For groundwater with total dissolved solids lower than 1400 mg/L at landfill sites, a strong positive linear correlation (r = 0.83) was revealed between δC and δC. Based on these insights, δH versus δC plots and RDA using δH and δC as response variables were proposed to localize leak points at both lined landfills and leachate facilities. These findings further understanding of the isotopic fractionation features of hydrogen, carbon, and oxygen and provide novel environmental tracer methods for investigating leachate leak points at MSW landfill sites.
迫切需要对众多垃圾填埋场的渗滤液泄漏情况进行调查。本研究探讨了利用δH和溶解碳的δC差值（δC）等环境示踪方法来定位垃圾填埋场的渗滤液泄漏点。在2021年至2023年期间，对中国某垃圾填埋场不同区域的渗滤液和地下水中的δH、δC、δC、δO以及一系列物理化学指标（如总溶解固体、温度和氧化还原电位）进行了监测。此外，还收集了来自12个已发表的垃圾填埋案例的这些参数（即同位素组成和物理化学指标）的数据，这些地下水/渗滤液数据点位于距离垃圾填埋场边界1公里以内。然后，使用垃圾填埋场检测到的和收集到的参数进行了Pearson相关分析和冗余分析（RDA）等统计分析。结果发现，渗滤液与背景地下水之间的相互作用强度显著控制了氢和碳的同位素分馏特征，主要污染指标（总溶解固体、化学需氧量和氨氮）的含量以及氧化还原电位是关键影响因素。据此，确定用于指示渗滤液泄漏点的水型为与背景地下水或降水有显著相互作用的渗滤液（LBGP）。在高度厌氧的垃圾填埋条件下，渗滤液中的δH与δC呈现出良好的线性相关性（0.81≤r＜1.0），并且LBGP中的δH和δC组合与其他水型中的组合有显著差异。对于垃圾填埋场中总溶解固体低于1400mg/L的地下水，δC与δC之间呈现出强正线性相关性（r = 0.83）。基于这些认识，提出了以δH和δC为响应变量的δH对δC图和RDA，用于定位有衬里的垃圾填埋场和渗滤液处理设施的泄漏点。这些发现进一步加深了对氢、碳和氧同位素分馏特征的理解，并为调查城市生活垃圾填埋场的渗滤液泄漏点提供了新的环境示踪方法。
