Department of Earth and Environmental Sciences, Korea University, Seoul, South Korea.
Biosciences Division, Argonne National Laboratory, Lemont, IL 60439, USA.
J Environ Manage. 2024 Sep;368:122127. doi: 10.1016/j.jenvman.2024.122127. Epub 2024 Aug 11.
Construction and demolition wastes (CDWs) have become a significant environmental concern due to urbanization. CDWs in landfill sites can generate high-pH leachate and various constituents (e.g., acetate and sulfate) following the dissolution of cement material, which may affect subsurface biogeochemical properties. However, the impact of CDW leachate on microbial reactions and community compositions in subsurface environments remains unclear. Therefore, we created columns composed of layers of concrete debris containing-soil (CDS) and underlying CDW-free soil, and fed them artificial groundwater with or without acetate and/or sulfate. In all columns, the initial pH 5.6 of the underlying soil layer rapidly increased to 10.8 (without acetate and sulfate), 10.1 (with sulfate), 10.1 (with acetate), and 8.3 (with acetate and sulfate) within 35 days. Alkaliphilic or alkaline-resistant microbes including Hydrogenophaga, Silanimonas, Algoriphagus, and/or Dethiobacter were dominant throughout the incubation in all columns, and their relative abundance was highest in the column without acetate and sulfate (50.7-86.6%). Fe(III) and sulfate reduction did not occur in the underlying soil layer without acetate. However, in the column with acetate alone, pH was decreased to 9.9 after day 85 and Fe(II) was produced with an increase in the relative abundance of Fe(III)-reducing bacteria up to 9.1%, followed by an increase in the methanogenic archaea Methanosarcina, suggestive of methanogenesis. In the column with both acetate and sulfate, Fe(III) and sulfate reduction occurred along with an increase in both Fe(III)- and sulfate-reducing bacteria (19.1 and 17.7%, respectively), while Methanosarcina appeared later. The results demonstrate that microbial Fe(III)- and sulfate-reduction and acetoclastic methanogenesis can occur even in soils with highly alkaline pH resulting from the dissolution of concrete debris.
建筑和拆除废物（CDW）由于城市化而成为一个重大的环境问题。在填埋场中，水泥材料溶解后会产生高 pH 值的浸出液和各种成分（例如乙酸盐和硫酸盐），这可能会影响地下生物地球化学性质。然而，CDW 浸出液对地下环境中微生物反应和群落组成的影响尚不清楚。因此，我们创建了由混凝土碎片层（CDS）和下方无 CDW 土壤组成的柱体，并向其中注入含有或不含有乙酸盐和/或硫酸盐的人工地下水。在所有柱体中，下方土壤层的初始 pH 值 5.6 在 35 天内迅速升高至 10.8（不含乙酸盐和硫酸盐）、10.1（含硫酸盐）、10.1（含乙酸盐）和 8.3（含乙酸盐和硫酸盐）。在整个培养过程中，嗜碱性或耐碱性微生物（包括 Hydrogenophaga、Silanimonas、Algoriphagus 和/或 Dethiobacter）在所有柱体中均占主导地位，并且在不含乙酸盐和硫酸盐的柱体中丰度最高（50.7-86.6%）。在不含乙酸盐的下方土壤层中没有发生 Fe(III)和硫酸盐还原。然而，在仅含有乙酸盐的柱体中，pH 值在第 85 天后降至 9.9，并且随着 Fe（III）还原细菌相对丰度的增加，产生了 Fe(II)，随后甲烷生成古菌 Methanosarcina 的丰度增加，表明发生了甲烷生成。在同时含有乙酸盐和硫酸盐的柱体中，Fe(III)和硫酸盐还原伴随着 Fe(III)-和硫酸盐还原细菌（分别为 19.1%和 17.7%）的增加而发生，而 Methanosarcina 出现较晚。结果表明，即使在由于混凝土碎片溶解而导致土壤 pH 值高度碱性的情况下，微生物 Fe(III)和硫酸盐还原以及乙酸盐嗜甲烷生成也可以发生。
