Pools and fluxes of mercury and methylmercury in two forested catchments in Germany.
Pools and fluxes of mercury and methylmercury in two forested catchments in Germany.
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DOI：
10.1016/s0048-9697(00)00565-9
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发表时间：
2000-10
期刊：
影响因子：
--
通讯作者：
D. Schwesig;E. Matzner
中科院分区：
文献类型：
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作者：
D. Schwesig;E. Matzner
汞(Hg)和甲基汞(CH3Hg+)是全球性污染物，但关于中欧土壤和集水区大气输入、分布和迁移率的信息很少。这项研究的目的是调查这些化合物在德国东北部巴伐利亚州一个落叶和针叶流域的输入和输出通量，并在流域尺度上估计总汞(Hgtot)和CH3Hg+的池和迁移率。从1998年4月到1999年4月，每两周收集一次总体降水、穿透雨、凋落物和径流。对几个土壤剖面进行了采样，以估计集水区中汞化合物的含量。在这两个流域，Hgtot含量最高的是森林地面Oa层(高达500ngg−1)，按60 cm土层计算，Hgtot的土壤储量在针叶林约为890g ha−1，在落叶集水区约为190g ha−1。旱地土壤CH3Hg+含量最高的是林地表层，针叶林土壤CH3Hg+储量为4.35g ha−1，落叶集水区土壤CH3Hg+储量为0.59gha−1。Hgtot的年总沉降量(总沉降量不是直接测量的，而是根据穿透雨和凋落物计算的)在针叶林为541mgha−1年−1，在落叶集水区为618mgha−1年−1。CH3Hg+的总沉降率分别为3.5mgha和2.6mgha−1年−1。凋落物对落叶流域汞和CH3Hg+总沉降量的贡献率为55%。在针叶林流域，凋落物对Hgtot总沉降量的贡献率仅为29%，对CH3Hg+的贡献率为55%。到目前为止，CH3Hg+和Hgtotreme沉积在流域中的比例最大(85%在针叶林，95%在落叶林)。与瑞典边远流域相比，我国流域Hgot的沉降量和径流输出量较高，而CH3Hg2+的沉降量和输出量较低。与其他研究相比，年度预算显示这两个物种在集水区范围内的流动性没有差异。然而，森林地表径流通量和CH3Hg+和Hgtt含量的反向梯度的时间格局表明，在较短的时间尺度上，迁移率存在差异。
Mercury (Hg) and methylmercury (CH3Hg+) are global pollutants, but little information is available on rates of atmospheric input, distribution and mobility in soils and catchments of central Europe. The objectives of this study were to investigate input and output fluxes of these compounds in a deciduous and a coniferous catchment in NE Bavaria (Germany), and to estimate pools and mobility of total Hg (Hgtot) and CH3Hg+at the catchment scale. Bulk precipitation, throughfall, litterfall and runoff were collected biweekly from April 1998 to April 1999. Several soil profiles were sampled to estimate pools of Hg compounds in the catchments. In both catchments highest contents of Hgtotwere found in the Oa layer of the forest floor (up to 500 ng g−1) and the soil storage of Hgtotcalculated for a soil depth of 60 cm was approximately 890 g ha−1in the coniferous and 190 g ha−1in the deciduous catchment. Highest contents of CH3Hg+in upland soils were observed in the Oi layer of the forest floor, and soil storage of CH3Hg+was 4.35 g ha−1in the coniferous and 0.59 g ha−1in the deciduous catchment. The annual total deposition of Hgtot(total deposition not measured directly but calculated from throughfall and litterfall) was 541 mg ha−1year−1in the coniferous and 618 mg ha−1year−1in the deciduous catchment. Total deposition rates of CH3Hg+were 3.5 and 2.6 mg ha−1year−1. The contribution of litterfall to the total deposition of Hgtotand CH3Hg+was 55% in the deciduous catchment. In the coniferous catchment, the contribution of litterfall to total deposition was only 29% for Hgtot, but 55% for CH3Hg+. By far the largest proportion of the deposited CH3Hg+and Hgtotremained in the catchments (85% in the coniferous, 95% in the deciduous). As compared to remote Swedish catchments, deposition and output via runoff of Hgtotwere higher, but deposition and output of CH3Hg+were lower in our catchments. In contrast to other studies, the annual budget revealed no differences in the mobility between the two species at the catchment scale. However, temporal patterns of the runoff fluxes and converse gradients of CH3Hg+and Hgtotcontents in the forest floor indicated differences in mobility on shorter time scales.