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.     

前工业时期的大气污染:它对于对酸性物质敏感的瑞典湖泊的Ph值来说是至关重要的吗?

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.     

A palaeolimnological assessment of diatom production responses to lake acidification

To quantify diatom palaeoproduction responses to lake acidification, a whole-basin diatom accumulation rate was calculated for the small acidified lake Gaffeln, in the G?rdsj?n catchment in south-west Sweden. Changes in the relative frequency of diatom assemblages to acidification were typical of other lakes in the area, notably a decline in planktonic diatoms after approximately 1900 and increase in acid-tolerant benthic species (e.g. Eunotia spp. and Tabellaria binalis). Single deep-water cores could be used to infer past changes in diatom production because of changed sediment-microfossil deposition patterns, probably due to the development of a benthic algal mat in the littoral zone. The basin mean total diatom accumulation rate (based on eight cores) was approximately constant over the last 150 years, while planktonic diatoms decreased from 0.3 x 10(6) frustules cm(-2) year(-1) prior to 1900 to trace levels in the 1970s. There was, however, a corresponding increase in the accumulation of benthic diatoms over the same period, from 0.5 to 1 x 10(6) frustules cm(-2) year(-1) between 1950 and the present, together with changed community structure. The increase in benthic species probably reflects an expansion of the littoral zone as light transparency increased.     

Partition coefficients of organic chemicals derived from reversed phase thin layer chromatography: Evaluation of methods and application on phosphate esters,polychlorinated paraffins and some PCB-substitutes

The application of reversed phase high performance thin layer chromatography has been evaluated for determination of octanol-water partition coefficients (P_oct) of organic chemicals. Best correlations between log P_oct and R_M-values were obtained on a C₁₈-bonded stationary phase using acetone-water or acetonitrile-water mixtures as eluting solvent. The latter mixture is preferred in work with high pressure liquid chromatography. A number of aryl and alkyl/aryl phosphate esters, polychlorinated paraffins and chemicals suggested as PCB-substitutes were chromatographed and the corresponding log P_oct-values calculated. Values for the phosphate esters corresponded reasonably well with previously reported data while data for other, often more complex compound mixtures (eg PCB-substitutes), need further evaluation. The use of the chromatographic system for screening purposes in work on environmentally significant data of possible organic pollutants is discussed.     

Monitoring compared with paleolimnology: implications for the definition of reference condition in limed lakes in Sweden

Surface water acidification was identified as a major environmental problem in the 1960s. Consequently, a liming program was launched in Sweden in the 1970s. The primary purpose of liming is to restore conditions that existed prior to acidification. To reach this goal, as well as achieve 'good status' (i.e. low levels of distortion resulting from human activity) in European freshwaters until 2016 under the European Union Water Framework Directive, lake data are required to define reference conditions. Here, we compare data from chemical/biological monitoring of 12 limed lakes with results of paleolimnological investigations, to address questions of reference conditions, acidification, and restoration by liming. Using diatom-based lake-water pH inferences, we found clear evidence of acidification in only five of the 12 lakes, which had all originally been classified as acidified according to monitoring data. After liming, measured and diatom-inferred pH agree well in seven lakes. The sediment record of three of the five remaining lakes gave ambiguous results, presumably due to sediment mixing or low sediment accumulation rates. It is difficult to determine whether liming restored the lakes to a good status, especially as some of the lakes were not acidified during the twentieth century. In addition to acid deposition, other factors, such as natural lake and catchment ontogeny or human impact through agricultural activity, influence lake acidity. This study shows that monitoring series are usually too short to define reference conditions for lakes, and that paleolimnological studies are useful to set appropriate goals for restoration and for evaluation of counter measures.     

Functional clustering of varved lake sediment to reconstruct past seasonal climate

Annually laminated (varved) lake sediments constitutes excellent environmental archives, and have the potential to play an important role for understanding past seasonal climate with their inherent annual time resolution and within-year seasonal patterns. We propose to use functional data analysis methods to extract the relevant information with respect to climate reconstruction from the rich but complex information in the varves, including the shapes of the seasonal patterns, the varying varve thickness, and the non-linear sediment accumulation rates. In particular we analyze varved sediment from lake Kassjön in northern Sweden, covering the past 6400 years. The properties of each varve reflect to a large extent weather conditions and internal biological processes in the lake the year that the varve was deposited. Functional clustering is used to group the seasonal patterns into different types, that can be associated with different weather conditions. The seasonal patterns were described by penalized splines and clustered by the k-means algorithm, after alignment. The observed (within-year) variability in the data was used to determine the degree of smoothing for the penalized spline approximations. The resulting clusters and their time dynamics show great potential for seasonal climate interpretation, in particular for winter climate changes.     

Local Governance and Climate Change: Reflections on the Swedish Experience

Abstract

The focus of this article is the Swedish experience of local governance and climate change, including mitigation and adaptation. The municipal response to these two challenges is set within a broader policy context that acknowledges Sweden as a pioneer in environmental governance, including its comparatively high ambitions with regard to the reduction of greenhouse ga emissions. Central–local relations in climate policy are analysed, and climate change mitigation and adaptation are exemplified by some snapshots of municipal initiatives, including the popular habit of networking between municipalities within as well as across national borders. In conclusion we briefly evaluate the Swedish local governance experience of climate change mitigation and adaptation to date as characterized by radical rhetoric and ambitious goals combined with a lot of promising initiatives, although still with fairly modest results in terms of tangible outcomes. Finally, we reflect upon what we consider to be the most important questions for future research on local governance and climate change.     

Cocky and climate smart? Climate change mitigation and place-branding in three Swedish towns

Sustainable development has emerged as a distinctive marker of place identity in addition to traditional markers such as buildings and spectacles. Climate change mitigation as a potential place brand, indicating sustainable development, is in focus of this article, comparing such efforts in three Swedish towns. Based on documentary studies and interviews, it demonstrates how one town has been successful in branding itself as “the Greenest City in Europe”, whereas mitigation efforts in two other towns are barely known outside the town halls. In the first case, a combination of material, symbolic, and institutional components has been decisive in establishing a brand with internal and external legitimacy. This case highlights the importance of a dedicated network of influential actors and a potent governance structure visualising the will of a town to make its climate mitigation efforts known. Despite similar material conditions, the two others come short on the symbolic and the institutional dimensions, although they may still have a potential for future success in terms of mitigation both in practice and as a marker of identity.