Selenium-inhibited monomethylmercury (MeHg) production is an attractive strategy for mitigating the risks of MeHg exposure. However, it is poorly understood the methylation potential of mercury selenide (HgSe) particles during their aging in soils and sediments. Net MeHg production in three floodplain soils amended with different geochemical species of mercury selenides, i.e., dissolved inorganic mercury freshly mixed with selenite (Hg(II)+Se(IV)), HgSe nanoparticles (45.2 ± 0.5 nm) and microparticles (> 1 μm) is examined. Among mercury types, the methylation from nanoparticulate HgSe was similar to (0.05 – 0.5 % vs. 0.1 – 0.4 %, yellow brown soil) or 12.9 – 21.0 times lower (0.02 – 0.1 vs. 0.6 – 1.5 %, black soil) than that from Hg(II)+Se(IV); however, net MeHg production from HgSe nanoparticles (0.02 – 0.5 %) was 1.9 – 15.5 times greater than HgSe microparticles (< 0.05 %) in all soils. Furthermore, net MeHg production from nanoparticulate HgSe varied significantly among soil types, attributable to differences in soil organic matter contents (2.4–5.8%) and microbial methylator community among soils. These results address the importance of geochemical intermediates of mercury selenide precipitation reactions and soil properties in MeHg production, and develop Se-based remediation strategy to minimize negative effects of MeHg on environmental and human health.

硒抑制一甲基汞（MeHg）的生产是降低MeHg暴露风险的一种有吸引力的策略。但是，人们对硒化汞（HgSe）颗粒在土壤和沉积物中老化过程中的甲基化潜力了解甚少。三种洪泛平原土壤的MeHg净生产量经过不同的地球化学物质硒化汞修正，即溶解的无机汞与亚硒酸盐（Hg（II）+ Se（IV）），HgSe纳米颗粒（45.2±0.5 nm）和微粒（> 1 （μm）。在汞类型中，来自纳米颗粒HgSe的甲基化类似于（0.05 – 0.5％vs. 0.1 – 0.4％，黄褐色土壤）或比其低12.9 – 21.0倍（0.02 – 0.1 vs. 0.6 – 1.5％，黑土壤）。来自Hg（II）+ Se（IV）; 但是，HgSe纳米颗粒的净MeHg产量（0.02 – 0.5％）为1.9 – 15。在所有土壤中，其含量均比HgSe微粒（<0.05％）大5倍。此外，由于土壤有机质含量（2.4-5.8％）和土壤间微生物甲基化剂群落的差异，纳米颗粒HgSe的净MeHg产量在土壤类型之间也有很大差异。这些结果解决了硒化汞沉淀反应的地球化学中间产物和土壤特性在MeHg生产中的重要性，并开发了基于Se的修复策略，以最小化MeHg对环境和人类健康的负面影响。