Department of Natural Sciences and Environmental Health, Faculty of Technology, Natural Sciences and Maritime Sciences, University of South-Eastern Norway, Bø, Norway.
Sci Total Environ. 2021 Feb 10;755(Pt 2):143725. doi: 10.1016/j.scitotenv.2020.143725. Epub 2020 Nov 14.
Indicators of redox conditions; oxygen, sulphate, nitrate, ammonium, iron and manganese, and in addition, bicarbonate and total organic carbon were studied in groundwater samples contaminated by leachate emanating from Revdalen Landfill (Norway). Based on these variables, the study aimed to deduce the redox conditions in the aquifer. Literature on landfill leachate contamination of confined aquifers is scarce and to the best of our knowledge, this study, which describes long-term analysis of redox chemistry, is the first of its kind in such an environment. Groundwater samples were monitored for a period of 24 years, enabling us to describe redox conditions on both short-term and long-term bases. Levels of measured parameters in the contaminated aquifer varied spatially and with time, but were generally elevated except oxygen; pH (4.9-8.8), oxygen (0-11.3 mg/L), sulphate (0-28 mg/L), nitrate (0-16 mg N/L), ammonium (0.02-40 mg/L), iron (0-99 mg/L), manganese (0.06-16 mg/L), bicarbonate (22-616 mg/L) and total organic carbon (1.3-47 mg/L). From the result, levels of iron, manganese, nitrate and ammonium violated the Norwegian drinking water norms. However, iron, ammonium, total organic carbon and bicarbonate showed strong attenuation along the groundwater flow path. By contrast, oxygen, nitrate and sulphate increased farther out in the plume. The redox conditions that developed in the aquifer were similar to those previously reported for phreatic aquifers, structuring by proximity to the landfill as sulphate-reducing, iron-reducing, manganese-reducing, nitrate-reducing, and finally aerobic condition. Eventually, there was an apparent breakdown of this system due to ecosystem shift in the landfill when leachable reduced ions were depleted and the landfill became aerobic. Overall, the redox framework provided remarkable attenuation to contaminants, and thus prevented potential degradation of ecological health due to the landfill leachate.
本研究以源自 Revdalen 垃圾填埋场渗滤液污染的地下水样本为研究对象，分析了其中的氧化还原条件指示物，包括氧气、硫酸盐、硝酸盐、铵、铁和锰，此外还研究了碳酸氢盐和总有机碳。本研究旨在基于这些变量推导出含水层的氧化还原条件。有关封闭含水层中垃圾渗滤液污染的文献相对较少，据我们所知，本研究是此类环境中首例对氧化还原化学进行长期分析的研究。地下水样本监测持续了 24 年，使我们能够从短期和长期两个方面描述氧化还原条件。受污染含水层中测量参数的水平在空间和时间上均存在差异，但总体上均升高，除氧气外；pH 值（4.9-8.8）、氧气（0-11.3mg/L）、硫酸盐（0-28mg/L）、硝酸盐（0-16mgN/L）、铵（0.02-40mg/L）、铁（0-99mg/L）、锰（0.06-16mg/L）、碳酸氢盐（22-616mg/L）和总有机碳（1.3-47mg/L）。结果表明，铁、锰、硝酸盐和铵的含量均超过了挪威饮用水标准。然而，铁、铵、总有机碳和碳酸氢盐在地下水流动路径上表现出强烈的衰减。相比之下，氧气、硝酸盐和硫酸盐在羽流的更远区域增加。含水层中形成的氧化还原条件与先前报道的潜水含水层中的条件相似，这是由于靠近垃圾填埋场而形成的硫酸盐还原、铁还原、锰还原、硝酸盐还原和最终需氧条件。最终，由于垃圾填埋场中的生态系统发生转变，可浸出的还原离子耗尽，垃圾填埋场变得需氧，这种系统明显崩溃。总的来说，氧化还原框架对污染物具有显著的衰减作用，从而防止了由于垃圾渗滤液而导致生态健康潜在恶化。
