Eklöf Karin, de Wit Heleen, Eckley Chris S, Eagles-Smith Collin A, Eggert Susan L, Mackereth Robert W, Skyllberg Ulf, Ukonmaanaho Liisa, Verta Matti, Allan Craig, Emilson Erik J S, Kidd Karen A, Mitchell Carl P J, Munthe John, Sallantaus Tapani, Segersten Joel, Bravo Andrea G, Kolka Randall K, McCarter Colin P R, Porvari Petri, Ring Eva, Sebestyen Stephen D, Sikström Ulf, Zetterberg Therese Sahlén
Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala SE-75007, Sweden.
Norwegian Institute for Water Research, Økernveien 94, Oslo 0579, Norway.
Environ Sci Technol. 2025 Aug 5;59(30):15944-15955. doi: 10.1021/acs.est.5c02787. Epub 2025 Jul 22.
Forest harvesting can lead to mercury (Hg) mobilization from soils to aquatic habitats and promote the transformation of inorganic Hg to highly neurotoxic and bioaccumulative methyl-Hg (MeHg). Multiple past studies reveal broad variation of stream water MeHg and total Hg (THg) concentration responses to forest harvesting, which has confounded messaging to forest and resource managers. To advance beyond divergent and sometimes contradictory findings, we synthesized information for 23 previously studied catchments in North America and Fennoscandia and compiled a uniform set of soil, landscape, and harvesting properties to identify forest management, riparian, and hillslope factors that influence responses of stream water MeHg and THg concentrations. From this synthesis, we found catchments with high soil moisture and organic soil layers >100 cm to be at highest risk for disturbance-induced increases in MeHg formation after harvest but not necessarily affecting concentrations of MeHg in stream waters. Instead, the combination of MeHg formation in soils along with factors that affect mobilization with runoff to streams most influenced how forest harvest affects MeHg concentrations in stream waters.
森林采伐会导致汞（Hg）从土壤中释放到水生栖息地，并促进无机汞向具有高度神经毒性和生物累积性的甲基汞（MeHg）转化。过去的多项研究表明，溪流水体中甲基汞和总汞（THg）浓度对森林采伐的响应存在广泛差异，这给森林和资源管理者传递信息带来了困扰。为了超越这些不同甚至相互矛盾的研究结果，我们综合了北美和芬诺斯堪的亚地区23个此前已研究流域的信息，并编制了一套统一的土壤、景观和采伐属性，以确定影响溪流水体中甲基汞和总汞浓度响应的森林管理、河岸带和山坡因素。通过这项综合研究，我们发现土壤湿度高且有机土层厚度大于100厘米的流域，在采伐后因干扰导致甲基汞生成增加的风险最高，但不一定会影响溪流水体中甲基汞的浓度。相反，土壤中甲基汞的生成与影响径流进入溪流的迁移因素相结合，对森林采伐如何影响溪流水体中甲基汞浓度的影响最大。
