Heal K V
University of Edinburgh, Institute of Ecology & Resource Management, Scotland, UK.
Sci Total Environ. 2001 Jan 29;265(1-3):169-79. doi: 10.1016/s0048-9697(00)00657-4.
Manganese (Mn) in surface waters is a micronutrient, but elevated concentrations are toxic to fish and impair drinking water quality. In Scotland, undesirable Mn concentrations (> 0.05 mg l(-1)) occur predominantly in upland freshwaters because the acidic pH and organic nature of catchment soils favour Mn mobilisation. The relationship between upland land-use in Scotland and Mn concentrations in surface waters is reviewed. Conifer afforestation is associated with enhanced Mn in runoff. Mn is leached from conifer foliage and litter, and mature conifers enhance acid deposition and loss of Mn from acidified catchment soils. After harvesting, increased soil pools of water-soluble Mn and elevated Mn concentrations in runoff have been observed. Liming, fertiliser addition, drainage ditch construction and ploughing to improve upland pastures, and muirburn on grouse moors may also increase Mn concentrations in runoff, but the evidence is less clear-cut. The extent to which land-use influences Mn concentrations in upland catchments in Scotland is modified by catchment hydrology and soil type. Catchment geology, instream processes and standing water stratification are probably lesser influences on Mn concentrations in surface waters of upland catchments in Scotland. The location of land-use in upland catchments, especially in the riparian zone, is critical in determining its effect on Mn in runoff. Climate change is expected to increase Mn concentrations in runoff from upland catchments in Scotland because of predicted changes in soil hydrology.
地表水中的锰（Mn）是一种微量营养素，但浓度升高对鱼类有毒，并会损害饮用水质量。在苏格兰，不理想的锰浓度（>0.05毫克/升）主要出现在高地淡水中，因为集水区土壤的酸性pH值和有机性质有利于锰的活化。本文综述了苏格兰高地土地利用与地表水中锰浓度之间的关系。针叶林造林与径流中锰含量的增加有关。锰从针叶和枯枝落叶中淋溶出来，成熟的针叶树会增加酸性沉降以及酸化集水区土壤中锰的流失。采伐后，已观察到土壤中水溶性锰的含量增加，径流中的锰浓度升高。为改善高地牧场而进行的石灰处理、施肥、排水沟建设和耕作，以及松鸡荒原上的烧荒，也可能会增加径流中的锰浓度，但证据不太明确。集水区水文和土壤类型会改变土地利用对苏格兰高地集水区锰浓度的影响程度。集水区地质、河道内过程和静水层化对苏格兰高地集水区地表水中锰浓度的影响可能较小。高地集水区土地利用的位置，尤其是在河岸带的位置，对于确定其对径流中锰的影响至关重要。由于预计土壤水文状况会发生变化，气候变化预计会增加苏格兰高地集水区径流中的锰浓度。
