Larssen Thorjørn, de Wit Heleen A, Wiker Marianne, Halse Kine
Norwegian Institute for Water Research, Gaustadalléen 21, Oslo, Norway.
Sci Total Environ. 2008 Oct 15;404(2-3):290-6. doi: 10.1016/j.scitotenv.2008.03.013. Epub 2008 Apr 29.
We present input and output fluxes of total mercury (Hg(tot)) and methyl mercury (MeHg) based on throughfall, litterfall and stream water samples from 2004/2005 from a small forested catchment (Langtjern) in Norway. Hg(tot) input via throughfall and litterfall was estimated to 6.7 and 2.7 microg m(-2) yr(-1), respectively, which is considerably lower than previously reported from other boreal catchments in Scandinavia. A likely cause for the low input flux is the sparseness and low productivity of the forest in the Langtjern catchment, with less atmospheric scavenging and lower litterfall fluxes than previously studied sites. In addition there has been a general decrease in mercury (Hg) in the atmosphere on the northern hemisphere in the last decade. The estimated output flux of Hg(tot) with surface water was 2.5 microg m(-2) yr(-1), which is comparable to what has been reported elsewhere. The ratio of Hg(tot) output flux to input flux was 26%, which is considerably higher than reported from other sites. This illustrates that catchment properties have greater importance for surface water export of Hg than the current atmospheric input. The estimated total soil pool of Hg(tot) in the catchment was 17.4 mg m(-2). This corresponds to roughly 8000 years of the current surface water output flux and 2000 years of the current input flux.
我们展示了基于2004/2005年挪威一个小型森林集水区（朗特耶恩）的穿透雨、凋落物和溪水样本得出的总汞（Hg(tot)）和甲基汞（MeHg）的输入和输出通量。通过穿透雨和凋落物输入的Hg(tot)估计分别为6.7和2.7微克/平方米·年，这大大低于此前斯堪的纳维亚半岛其他北方集水区的报告值。输入通量低的一个可能原因是朗特耶恩集水区森林的稀疏和低生产力，与之前研究的地点相比，大气清除作用较小且凋落物通量较低。此外，在过去十年中，北半球大气中的汞（Hg）普遍减少。地表水输出的Hg(tot)估计通量为2.5微克/平方米·年，这与其他地方的报告值相当。Hg(tot)输出通量与输入通量的比值为26%，这大大高于其他地点的报告值。这表明集水区特性对汞的地表水输出比当前大气输入更为重要。该集水区Hg(tot)的估计土壤总储量为17.4毫克/平方米。这大致相当于当前地表水输出通量的8000年和当前输入通量的2000年。
