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- Hjortenkrans, David, 1968-
(författare)
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Road traffic metals : sources and emissions
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- As the environmental regulations and technical progress have forced the factories’ old “end of pipe” solutions to improve, the metal emissions from point sources have decreased. Instead, the diffuse consumption emissions from goods in use now are in focus. The increased awareness of traffic as a major diffuse metal emission source emphasizes the need for more detailed information on the various traffic related sources. The main scope of this thesis is to study specific parts of metal emissions from some road traffic related sub sources such as brake lining and tyres. The metals in focus are antimony (Sb), cadmium (Cd), copper (Cu), chromium (Cr), lead (Pb), nickel(Ni) and zinc (Zn), and the research quantifies emissions from the different sub sources, trace changes over time as well as dispersal patterns and metal mobility in the roadside environment. The results show that even if the road traffic associated metal stocks are small compared to total in use stocks, their emissions are of major importance. The updated figures show that despite material developments during the last 10 years, tyres still are one of the main sources of Zn and Cd, while it can be excluded as a source of concern for the other metals studied. Brake linings are shown to be an especially pronounced source for Cu and Sb. The Pb and Cd emissions from brake linings and tyres have decreased as a result of decreasing material concentrations in these sources, most likely a result of EU regulations. Further the results reveals galvanized goods to be a major road traffic related source for Zn. The results show that the total metal concentrations in roadside soils have increased 3-16 times compared to regional background during the last decades. Each metal has a limited dispersal distance from the roads as well as down in the soil profile. Most metals are found within 10 m from the road in the uppermost 10 cm of the topsoil. However, the sequential extractions show that a large part of the metals found in the soil are rather easily mobilized and can be redistributed if the roadside soils become disturbed. Metals emitted due to decelerating activities are not correlated to elevated concentrations near road junctions. Instead the metals appear to be more evenly spread along the whole driven distance. The study points out Sb as an element that might be problematic to analyse. For Sb, which is sparsely studied as a roadside contaminant, there is a need of more general knowledge as it has a high accumulation rate in roadside soils.
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- Öberg, Tomas
(författare)
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Persistent Organic Pollutants and the Environment : A Chemometric Approach to the Study of Halogenated Aromatics
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Concern is growing about the environmental and health effects of persistent organic pollutants (POPs), many of which are halogenated aromatic compunds. The research reported in this thesis focuses on factors determining their behaviour and release into the environment. The aims have been to relate molecular features with physical and chemical properties and to interpret casual relationships, with the common methodological approach of chemometrics.Quantitative structure-property relationships (QSPR) were investigated for polychlorinated biphenyls (PCB), polychlorinated diphenyl ethers (PCDE) and polybrominated diphenyl ethers (PBDE). QSPR models were developed from computationally derived descriptors using partial least squares regression (PLSR). The results show that it is possible to model and predict properties such as vapour pressure almost to the limit of the experimental error. The models obtained could be applied both to validate available experimental data and extend the current database of experimental determinations.The distribution and levels of brominated flame retardants (BFRs) in sewage sludge were investigated using exploratory data analysis (EDA), analysis of variance (ANOVA) and principal component analysis (PCA). The levels of polybrominated diphenyl ethers (PBDE) and biphenyls (PBB) agreed well with another investigation reported recently, but for tetrabromobisphenol A (TBBPA) there was a divergence, possible due to the analytical methodology. The variation among wastewater treatment plants was statistically significant, and three distinct types of technical products were shown to contribute.The formation and release of chlorinated aromatics was investigated in an industrial afterburner with a series of statistically design experiments. Th effect of temperature was studied with some detail and the results indicate different decomposition pathways for hydrocarbons and chlorinated aromatics. Additional factors were studied in a multifactor experiment, with a full factorial design in two blocks. Catalytic lowtemperature formation and chlorine input were both statistically highly significant factors. Polychlorinated dioxins (PCDD) and dibenzofurans (PCDF) showed a statistically significant correlation to chlorinated benzenes, and the results could thus be described and interpreted within a simple conceptual model. The efficiency of the final oxidation, the chlorine input and the presence of a catalyst (e.g. copper) control the thermal formation of the different groups of chlorinated aromatics.The reported investigations show that empirical 'soft' models can provide insight and understanding of complex chemical properties and reactions. Latent variable models and Taylor polynomials were able to approximate the behaviour of these systems within the investigated boundaries. The chemometric models and methods are thus likely to find use also in other areas of environmental science where theoretical understanding is still limited.
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- Grahn, Evastina, 1968-
(författare)
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Lake sediment as environmental archive : natural and anthropogenic influence on the chronology of trace elements
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The focus of this thesis is the historical pollution of some seldom-monitored trace elements (SMTEs; Ag, Be, Ga, In, Sb and Tl) that have been involuntarily released for several thousands of years but whose usage have increased during the industrial era. Sediment cores from four rural lakes in a south to north transect in central Sweden, and two urban lakes have been used as environmental archives for chronological studies. The historical development of the SMTEs is put in perspective of frequently monitored elements (Cd, Cu, Pb and Zn) that serve as a well-known anthropogenic signal. Dating of the sediments is made with 210Pb, 137Cs and 239,240Pu as well as acid leachable lead and the 206Pb/207Pb ratio. The impact of diagenetic redistribution is included, when necessary. The results show that site-specific reference concentrations are required in order to estimate the present pollution as well as its historical development. Atmospheric deposition is the principal pathway of transport in rural lakes and the concentrations are lowered towards the north. It is not possible from this material, however, to separate the direct deposition on the lake surfaces from the contribution from their catchments. From 21Pb, acid-leachable Pb and the 206Pb/207Pb ratio a minimum of four periods of pollution can be discerned. For the SMTEs the quantitatively most important period of pollution took place from the Second World War until present. The growth of the domestic industrialisation as well as the early industrialisation of central Europe and the British Isles are also distinguishable. The pollution history of Ag, In and Sb goes back for several centuries as a result of metal processing whereas the levels of thallium mainly increase as a result of industrialisation. For Ag and Tl in-sediment diagenetic redistribution limits the precision of the historical estimate. The preliminary interpretation of 137Cs and 239,240Pu indicates that they are less suitable as chronological markers in the system studied. The urban impact on the trace metal sediment content in the urban lakes was lower than expected, except for Au. There is a large impact from hydrological conditions on the studied system why further investigations are recommended.
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- Månsson, Nina, 1972-
(författare)
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Substance flow analyses of metals and organic compounds in an urban environment : – the Stockholm example
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The intensified use of materials, products and goods in our time involves massive consumption of metals and organic compounds that can be released from society to the environment in the various stages of production, use and waste. Depending on the circumstances this may give rise to environmental risks, as metals in general and certain organic substances may be toxic in the short or long term. So where have those metals and organic substances been utilized? In which products or environments? Substance flow analysis (SFA) is a method to deal with these issues. The results from the analysis are quantifications of flows and stocks in a systematic way and within defined system boundaries.In this thesis four main research areas are identified, which need to be addressed. i) Application of SFA on substances that have not been studied in this respect before, which can give knowledge about flows and stocks related to consumption of goods. ii) Development of SFA to meet the needs in studies of trends for the substance cycles and studies of quantification of potential changes. iii) Assessment of which different agents and actions that induce the changes, such as chemical regulations, environmental objectives and aims. To what extent can these changes be related to substance flows? iv) Finally to assess, how can SFA be useful in environmental decisions? The specified aims focus on the metals antimony (Sb), cadmium (Cd), lead (Pb) and mercury (Hg) and the group of organic compounds alkylphenol/alkylphenol ethoxylates (AP/APEO), in urban environments, exemplified with case studies of Stockholm, the capital of Sweden.This thesis is a result of five studies. Three were based mainly on the methodology of SFA (Paper I-III). It has also been important to develop the chemical analysis of metals in goods where there has been a lack of information (Paper IV). Furthermore, assessment of policy questions and chemical regulations involve qualitative approaches and discussions (Paper I and V).The results show urban flows and stocks of the metals Cd, Hg, Pb and Sb and the group of organic substances AP/APEO. The results confirm that goods are important for the release of the substances studied. For Sb, emissions from brake linings (96%) dominate, but there are small emissions from textiles, potential emissions from flame retarded goods and probably small point sources. For AP/APEO the textile emissions were previously underestimated and the SFA presented here included this and pose textiles and cleaning agents as major emission source to wastewater.To repeat studies and to compare results from different years was a development of the SFA-method, which showed that Cd and Hg are being phased out as the inflow and stocks show diminished amounts, whereas the emissions remain approximately constant when comparing 1995 with 2002/2003. For Pb it is possible to talk about a phase-out of some specific goods, but not in general for inflow and stock.The changes in urban metabolism could be related to environmental decisions, e.g. effects of local initiatives and in some cases voluntary initiatives, but also as result of prevailing chemicals regulation. The utility of SFAs for decision makers may be related to methodological issues, such as the accounting approach. However, the utility was also found to depend on the structure of the monitoring, that is screening in the environment and concentration in wastewaters and sewage sludge precede the source mapping conducted with SFA. Substance Flow Analysis will likely continue to serve as the broad information tool for one substance at a time, which will offer source characterization of diffuse emissions in urban environments.
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- Olsson, Susanna, 1977-
(författare)
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Environmental assessment of municipal solid waste incinerator bottom ash in road constructions
- 2005
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- There are several incentives for using bottom ash from municipal solid waste incineration (MSWI bottom ash) as a construction material, such as for road construction. These incentives include decreased disposal of material on landfills and a reduced amount of raw material extracted for road building purposes. However, one of the main obstacles to utilising the material is uncertainties regarding its environmental properties. The overall objective of this thesis is to describe the potential environmental impacts of utilising MSWI bottom ash in constructions and to improve the tools for environmental assessments. An environmental systems analysis (ESA) approach based on a life cycle perspective was outlined and used in a case study, with the aim of describing the differences in resource use and emissions that can be expected if crushed rock in the sub-base of a road in the Stockholm region in Sweden were to be substituted by MSWI bottom ash. The whole life cycle of the road was taken into account and the alternative disposal of the bottom ash was included. It was found that the studied alternatives would cause different types of potential environmental impact; whereas the conventional alternative with only crushed rock in the road’s sub-base would lead to larger use of energy and natural resources, the alternative with MSWI bottom ash in the sub-base would lead to larger contaminant leaching. It was concluded that a life cycle approach is needed in order to include both resource use and emissions in the comparison between the two alternative scenarios. The leaching of metals turned out to be the most important environmental aspect for the comparison and in particular the difference in copper (Cu) leaching was shown to be large. However, a large amount of Cu may not pose an environmental threat if the Cu is strongly bound to dissolved organic carbon (DOC). In order to improve the basis for toxicity estimates and environmental risk assessments, and thereby provide better input values for ESAs, the speciation of Cu to DOC in MSWI bottom ash leachate was studied. It was found that Cu to a large extent was bound to DOC, which is consistent with previous research. The results also suggest that the hydrophilic fraction of the MSWI bottom ash DOC is important for Cu complexation and that the pH-dependence for Cu complexation to MSWI bottom ash DOC is smaller than for natural DOC. This implies that models calibrated for natural DOC may give inconsistent simulations of Cu-DOC complexation in MSWI bottom ash leachate.
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