Vertical Distribution of Atmospheric Pollution Lead in Swedish Boreal Forest Soils

In order to understand the fate of anthropogenic lead (Pb)pollution in boreal forest soils, and to predict future trends, it is important to know where in the soil the pollution Pb is accumulated and how large the pollution and natural Pb inventories are in different soil horizons. We combined stable Pb isotope (²⁰⁶Pb/²⁰⁷Pb ratios) and concentration analyses to study Pb in podzol profiles and mor samples from old-growth forest stands at seven sites distributed from southern to northern Sweden. Additional samples were taken from managed forests, and from an agricultural field, to give some idea of the effects of land-use. Pb concentrations are typically 60–100 g g^-1 dry mass in the mor layer in southern Sweden and about 30 g g^-1 in northern Sweden. Pb isotope analyses show that virtually all of this Pb is pollution Pb. The isotope composition also shows that pollution Pb has penetrated downwards between 20–60 cm in the forest soils. The total pollution Pb inventories vary between 0.7–3.0 g m^-2 ground surface, with larger inventories in southern compared to northern Sweden. Although the highest Pb concentrations occur in the mor layer, the largest inventories of pollution Pb are found in the Bs-horizon. The limited investigation of Pb distribution and inventories in soils from managed forests did not point to any major difference compared to the old-growth forests. The agricultural field revealed, however, a completely deviating Pb profile with all pollution Pb evenly distributed in the 20 cm thick top-soil.     

Sediment evidence of early eutrophication and heavy metal pollution of Lake Mälaren, central Sweden

Lake M?laren 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-20th century nutrient levels in S?dra Bj?rkfj?rden, a basin in the eastern part of M?laren, were higher (c. 10-20 micrograms TP L-1) than previously assumed (c. 6 micrograms TP L-1). Stable lead isotope and lead concentration analyses from 3 basins (S. Bj?rkfj?rden, Gisselfj?rden and Ask?fj?rden) show that the lake was polluted in the 19th 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 20th century following closure of the mining and metal industry. The lead pollution from the old mining industry was large compared to late-20th century pollution from car emissions, burning of fossil fuels and modern industries.     

瑞典中部梅拉伦湖早期富营养化的沉积物证据及重金属污染

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6ugTP/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、矿石然料燃烧以及现代生产所造成的污染要严重.