Mercury (Hg) is a pollutant of concern across Canada and transboundary anthropogenic Hg sources presently account for over 95% of national anthropogenic Hg deposition. This study applies novel statistical analyses of 82 high-resolution dated lake sediment cores collected from 19 regions across Canada, including nearby point sources and in remote regions and spanning a full west–east geographical range of ∼4900 km (south of 60°N and between 132 and 64°W) to quantify the recent (1990–2018) spatial and temporal trends in anthropogenic atmospheric Hg deposition. Temporal trend analysis shows significant synchronous decreasing trends in post-1990 anthropogenic Hg fluxes in western Canada in contrast to increasing trends in the east, with spatial patterns largely driven by longitude and proximity to known point source(s). Recent sediment-derived Hg fluxes agreed well with the available wet deposition monitoring. Sediment-derived atmospheric Hg deposition rates also compared well to the modeled values derived from the Hg model, when lake sites located nearby (<100 km) point sources were omitted due to difficulties in comparison between the sediment-derived and modeled values at deposition “hot spots”. This highlights the applicability of multi-core approaches to quantify spatio-temporal changes in Hg deposition over broad geographic ranges and assess the effectiveness of regional and global Hg emission reductions to address global Hg pollution concerns.

中文翻译：

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过去 30 年加拿大大气汞沉积的时空趋势量化

汞 (Hg) 是加拿大关注的污染物，跨界人为汞源目前占全国人为汞沉积的 95% 以上。本研究对从加拿大 19 个地区收集的 82 个高分辨率湖泊沉积物核心进行了新颖的统​​计分析，包括附近的点源和偏远地区，跨越了整个东西向地理范围约 4900 公里（北纬 60 度以南和132 和 64°W 之间）以量化最近（1990-2018 年）人为大气汞沉积的空间和时间趋势。时间趋势分析显示，加拿大西部 1990 年后人为汞通量呈显着同步下降趋势，而东部则呈上升趋势，空间格局主要由经度和与已知点源的接近程度驱动。最近沉积物衍生的 Hg 通量与可用的湿沉积监测非常吻合。沉积物衍生的大气 Hg 沉积速率也与 Hg 模型衍生的模拟值进行了很好的比较，当位于附近（<100 公里）点源的湖泊站点由于沉积时沉积物衍生值和模拟值之间的比较困难而被忽略时“热点”。这突出了多核方法的适用性，可量化广泛地理范围内汞沉积的时空变化，并评估区域和全球汞减排的有效性，以解决全球汞污染问题。100 公里）点源被省略，因为难以比较沉积“热点”的沉积物衍生值和模拟值。这突出了多核方法的适用性，可量化广泛地理范围内汞沉积的时空变化，并评估区域和全球汞减排的有效性，以解决全球汞污染问题。100 公里）点源被省略，因为难以比较沉积“热点”的沉积物衍生值和模拟值。这突出了多核方法的适用性，可量化广泛地理范围内汞沉积的时空变化，并评估区域和全球汞减排的有效性，以解决全球汞污染问题。