Environmental Chemistry and Technology Program, University of Wisconsin-Madison, 660 North Park Street, Madison, WI 53706-1484, USA.
Environ Pollut. 2012 Feb;161:299-310. doi: 10.1016/j.envpol.2011.09.026. Epub 2011 Oct 22.
Knowledge of the partitioning and sources of mercury are important to understanding the human impact on mercury levels in Lake Superior wildlife. Fluvial fluxes of total mercury (Hg(T)) and methylmercury (MeHg) were compared to discharge and partitioning trends in 20 sub-basins having contrasting land uses and geological substrates. The annual tributary yield was correlated with watershed characteristics and scaled up to estimate the basin-wide loading. Tributaries with clay sediments and agricultural land use had the largest daily yields with maxima observed near the peak in water discharge. Roughly 42% of Hg(T) and 57% of MeHg was delivered in the colloidal phase. Tributary inputs, which are confined to near-shore zones of the lake, may be more important to the food-web than atmospheric sources. The annual basin-wide loading from tributaries was estimated to be 277 kg yr(-1) Hg(T) and 3.4 kg yr(-1) MeHg (5.5 and 0.07 mg km(-2) d(-1), respectively).
了解汞的分配和来源对于理解人类活动对苏必利尔湖野生动物体内汞水平的影响至关重要。本文比较了总汞（Hg(T)）和甲基汞（MeHg）的河流通量与 20 个子流域的排放和分配趋势，这些子流域具有不同的土地利用和地质基底。年支流通量与流域特征相关，并进行了放大，以估算整个流域的负荷。具有粘土沉积物和农业用地的支流具有最大的日通量，最大通量出现在径流量峰值附近。大约 42%的 Hg(T)和 57%的 MeHg 以胶体相输送。限于湖泊近岸区的支流输入可能比大气源对食物网更为重要。估计从支流输入到整个流域的年负荷分别为 277 千克 Hg(T)和 3.4 千克 MeHg（分别为 5.5 和 0.07 毫克/平方公里/天）。
