Mercury is a global pollutant of critical concern but its movement through terrestrial upland systems is poorly understood. We investigated whether forest harvesting practices and varying hydrological conditions resulted in different subsurface transport pathways, fluxes and proportions of recent vs. ambient mercury in runoff. In a multiyear field experiment, we measured subsurface lateral mercury fluxes at three adjacent hillslope plots, including one that was not harvested, one where all biomass was removed after harvest, and one where residual biomass was left after harvest. Two different enriched stable mercury isotopes (Hg tracer) were added to the hillslope plots (one pre-harvest and one post-harvest) to help differentiate between recently deposited mercury and ambient mercury in soils, as well as to identify changes between years. More Hg tracer was recovered in runoff post-harvest (16.2–54.0 μg) than pre-harvest (3.7–11.8 μg) from both harvested hillslopes, but differences between harvested hillslopes were not significant. The movement of Hg tracer was governed by periods of near surface preferential flow that was enhanced by forest harvesting. Runoff Hg tracer concentrations were significantly and inversely related to both event runoff magnitude (R² = 0.85) and runoff ratio (R² = 0.81). Insignificant relationships between Hg tracer concentrations and both DOC and precipitation pH suggest that for recently deposited mercury, the overarching controls on mobilization were hydrological rather than biogeochemical. The dependence of mercury mobilization on the routing of precipitation to different subsurface flow pathways suggests an important interaction between climate and the age of mercury pools for mercury transport from terrestrial landscapes.

汞是引起人们高度关注的全球污染物，但是人们对汞在陆地高地系统中的移动知之甚少。我们调查了森林采伐方式和变化的水文条件是否导致径流中不同的地下运输途径，通量和近期汞与环境汞的比例。在多年的野外实验中，我们在三个相邻的山坡地块上测量了地下侧向汞通量，包括一个未被收获的山地，一个在收获后被清除掉的所有生物量以及一个在收获后留下了残留的生物量的水银通量。将两种不同的稳定汞富集同位素（Hg示踪剂）添加到了山坡地块上（一个收获前和一个收获后），以帮助区分土壤中最近沉积的汞和周围的汞，并确定年份之间的变化。从两个收获的山坡上，收获后的径流中（16.2-54.0μg）回收的汞示踪剂多于收获前（3.7-11.8μg），但收获的山坡之间的差异并不显着。汞示踪剂的运动受森林采伐增强的近地表优先流动时期的支配。径流Hg示踪剂浓度与两个事件径流幅度（R²  = 0.85）和径流比（R ²  = 0.81）。汞示踪剂浓度与DOC和沉淀pH值之间的关系不显着，这表明对于最近沉积的汞，总动员控制是水文而不是生物地球化学。汞动员对降水到不同地下流动路径的路由的依赖性表明，气候与从陆地景观中运输汞的汞库年龄之间存在重要的相互作用。