摘要
在瑞典,自20世纪中期以来,酸雨引起了大面积表层水的酸化。矿物燃料的燃烧和金属的生产中硫的排放是酸性物质积累的主要来源。在公众的意识中,酸性物质的积累是与工业时期有密切关系的,尤其是过去的50年。然而,在对湖水沉积物分析的基础上对湖水pH值的演变与大气污染的研究已经表明了从长远来看的重要性。在这里,使用沉积物的记录资料,我们提出了一个概念性的观点,即大规模的大气酸性积累,至少从中世纪开始就已经对环境产生影响。硫的来源是前工业时期的采矿业和金属工业,这些产业从硫化物矿砂中提取银、铅和其它金属。在瑞典南部这种早期过度的硫的积累并没有引起表层水的酸化;相反的,引起了水的碱化,即湖泊的pH值和生产力的增加。我们提出的作用机制是,过量的硫引起了流域土壤中快速的阳离子交换,改变了湖水中的铁—磷循环,在此循环过程中释放出磷,增加湖水的生产力。
Acid rain has caused extensive surface water acidification in Sweden since the mid-20^th century. Sulfur emissions from fossil-fuel burning and metal production were the main sources of acid deposition. In the public consciousness, acid deposition is strongly associated with the industrial period, in particular the last 50 years. However, studies of lake-water pH development and atmospheric pollution, based on analyses of lake sediment deposits, have shown the importance of a long-term perspective. Here, we present a conceptual argument, using the sediment record, that large-scale atmospheric acid deposition has impacted the environment since at least Medieval times. Sulfur sources were the pre-industrial mining and metal industries that produced silver, lead and other metals from sulfide ores. This early excess sulfur deposition in southern Sweden did not cause surface water acidification; on the contrary, it contributed to alkalization, i.e. increased pH and productivity of the lakes. Suggested mechanisms are that the excess sulfur caused enhanced cation exchange in catchment soils, and that it altered iron-phosphorus cycling in the lakes, which released phosphorus and increased lake productivity.
