摘要
梅拉伦湖是瑞典中部100多万居民的供水源和娱乐区,有重大的环境影响。为了建立评估目前的营养水平和重金属污染水平的背景资料,分析了取自湖泊的沉积岩心。从硅藻推断的湖水磷浓度表明,20世纪前南比约克盆地(梅拉伦湖东部的一个盆地)中的营养物水平比以前假定的(约6μgTP/L)要高(10～20μgTP/L)。从3个盆地(南比约克盆地、伊斯塞尔盆地以及艾斯雪盆地)获得的稳定性同位素和铅浓度分析结果表明,19世纪以及早些时候由于汇水盆地广泛开展的金属生产和加工,特别是在贝里斯拉根地区,使得该湖泊受到污染。在20世纪关闭了采矿和金属工厂之后该湖泊的铅污染形势有了相当大的好转。过去的采矿业所造成的铅污染比20世纪末汽车尾气排放、矿石燃料燃烧以及现代生产所造成的污染要严重。
Lake Malaren is the water supply and recreation area for more than 1 million people in central Sweden and subject to considerable environmental concern. To establish background data for assessments of contemporary levels of trophy and heavy metal pollution, sediment cores from the lake were analyzed. Diatom–inferred lake–water phosphorus concentrations suggest that pre-20^th century nutrient levels in Sodra Bjorkfjarden, a basin in the eastern part of Malaren, were higher (c. 10–20 μg TP L^-1) than previously assumed (c. 6 μg TP L^-1). Stable lead isotope and lead concentration analyses from 3 basins (S. Bjorkfjarden, Gisselfjarden and Askofjarden) show that the lake was polluted in the 19^th century and earlier from extensive metal production and processing in the catchment, particularly in the Bergslagen region. The lake has experienced a substantial improvement of the lead pollution situation in the 20^th century following closure of the mining and metal industry. The lead pollution from the old mining industry was large compared to late-20^th century pollution from car emissions, burning of fossil fuels and modern industries.
