School of Hydraulic and Environmental Engineering, Changsha University of Science and Technology, Changsha, China.
School of Hydraulic and Environmental Engineering, Changsha University of Science and Technology, Changsha, China.
Environ Res. 2024 Dec 15;263(Pt 1):120048. doi: 10.1016/j.envres.2024.120048. Epub 2024 Sep 21.
Black-odorous sediments provide ideal conditions for microbial mercury methylation. However, the multiple effects of carbon, sulfur, and iron on the microbial methylmercury of mercury in black-odorous sediments remains unclear. In this study, we conducted mercury methylation experiments using sediments collected from organically contaminated water bodies, as well as black-odorous sediments simulated in the laboratory. The results showed that black-odorous sediments exhibit a high capacity for mercury methylation. By simulating the blackening and odorization process in sediments, it was confirmed that dissolved oxygen, organic matter and sulfide were the primary factors triggering the black-odorous phenomenon in sediments. Regarding the influence of key factors in sediments on methylmercury formation, the batch tests demonstrated that high concentrations of organics additions (above 200 mg/L) may reduce bacterial activity and weaken mercury methylation in sediments. Under five different iron-sulfur ratios, the concentrations of methylmercury in the black-odorous sediments showed an increasing trend, the ratio of 5.0 Fe/S exhibited the highest MeHg accumulation. The iron-sulfur ratio in the sediment had a significant effect on the mercury methylation process, which was mainly due to the competition between Fe and Hg for sulfide sites and the adsorption/coprecipitation of Hg by FeS. These findings offer a potential avenue for further understanding and controlling mercury methylation, contributing to the mitigation of the potential threat of mercury pollution to the environment and human health.
黑臭沉积物为微生物汞甲基化提供了理想的条件。然而，碳、硫和铁对黑臭沉积物中汞的微生物甲基化的多种影响仍不清楚。在这项研究中，我们使用从有机污染水体中采集的沉积物以及在实验室中模拟的黑臭沉积物进行了汞甲基化实验。结果表明，黑臭沉积物具有很强的汞甲基化能力。通过模拟沉积物的黑化和发臭过程，证实溶解氧、有机物和硫化物是引发沉积物黑臭现象的主要因素。关于沉积物中关键因素对甲基汞形成的影响，批量测试表明，高浓度有机物添加（高于 200mg/L）可能会降低细菌活性并削弱沉积物中的汞甲基化。在五种不同的铁硫比下，黑臭沉积物中甲基汞的浓度呈上升趋势，5.0Fe/S 的比例表现出最高的 MeHg 积累。沉积物中的铁硫比对汞甲基化过程有显著影响，这主要是由于 Fe 和 Hg 对硫化物位点的竞争以及 FeS 对 Hg 的吸附/共沉淀。这些发现为进一步理解和控制汞甲基化提供了一个潜在的途径，有助于减轻汞污染对环境和人类健康的潜在威胁。
