Emission and precipitation of acidifying substances and metals has caused severe acidification and increased metal concentrations in lakes and streams in Sweden as well as many other countries during the last decades. To counteract the negative effects of acidification, liming has been used extensively in Sweden since the 1970’s, a treatment that has been called one of the largest man-maid manipulations of aquatic ecosystems ever. The aim of this thesis is to investigate the influence of acidification and liming on deposition of metals to lake sediments, and to look at the fate of metals in sediments during a possible reacidification process because of terminated liming. Studies of both surface sediments and dated sediment profiles sampled from limed lakes and non-limed reference lakes indicated that liming causes increased sedimentation of many metals. Increased deposition to the sediments was found for Al, Cd, Co, Ni, Fe, Mn and Zn, probably as a direct result of the increased pH. Liming was also found to increase the deposition of As and Cr, but that was probably due to the secondary effect of association to Fe and Mn complexes. No influence of lime treatment on the deposition of Hg, Pb and V to lake sediments could be demonstrated. The studies also indicated that acidification can decrease the deposition of Cd, Fe, Mn and possibly also Co and Zn to the sediments. The contribution from the used lime products to the metal load in sediments of lakes limed directly on the lake surface was also evaluated. The lime products were found to be an important source for Al, Cu and Ni and a relatively important source for Co, Cr, Hg and V, but did not seem to contribute much to the content of As, Cd, Pb or Zn in lake sediments. An experimental study of reacidification showed that (re)mobilisation of metals, e.g Al, Cd, Mn and Zn, from sediments may occur and that reacidification of formerly lime treated lakes may contribute to increased concentrations of these metals in the lake water. Cu, Fe and Pb are less affected by pH changes and the concentrations of these metals will probably not increase in lake water during reacidification. Altogether, the thesis shows that lime treatment causes increased deposition of many metals to the lake sediments, whereas reacidification may lead to remobilisation of some metals from the sediments with increased concentrations in the water phase as a result.

The pyrogenic particles formed from incomplete combustion of organic matter are often termed black carbon (BC) and they partake in many important biogeochemical processes. For instance, BC in water and sediment affects the solid-water partitioning of hydrophobic organic pollutants reducing their bioavailability. The key objective of this thesis was to test the chemothermal oxidation method (CTO) to quantify soot-BC in sediments. In the CTO method, sedimentary BC is isolated by removing non-pyrogenic organic matter through thermal combustion at 375°C under active airflow and subsequent removal of inorganic carbonates by adding hydrochloric acid. The CTO method was here shown to work well for quantifying the thermally more stable soot-BC phase. Another objective was to study sediment samples to measure the historical and spatial distribution of combustion products. First, historical fluxes of BC and polycyclic aromatic hydrocarbons (PAH) were investigated in a Swedish lake sediment. Increasing fluxes of BC and PAH were seen in sediment dated to the industrial revolution in the 1850s, the high coal usage in the early 1900s lead to a 5 time increase in BC flux relative to the pre-industrial flux, and the switch from coal to oil usage in the 1950s lead to a 46 time increase in PAH flux relative to the pre-industrial flux. Further, lower fluxes came from stricter emission controls in the 1960s, improvements in combustion technology and the usage of catalytic filters from mid-1980s. Modern sediment measured 20% lower BC flux and 5 times higher PAH flux relative to the pre-industrial fluxes. Secondly, the spatial distribution and sources of sedimentary soot-BC were studied in rivers in the Arctic region. The estimated BC flux was highest in the McKenzie (99 kton yr-1) whereas it was lowest in Yukon (1.1 kton yr-1). Contemporary biomass-derived BC was detected for the Yenisey, whereas fossil fuel derived BC was found for the Lena, Yukon and McKenzie.

Polybrominated diphenyl ethers (PBDEs) make up an important class of brominated flame retardants. The present production is mainly concentrated to DecaBDE but until recently also a significant production of PentaBDE and OctaBDE took place, leaving us with a large number of different PBDE congeners. The PBDEs have become widespread pollutants abiotically and in biota, particularly in high trophic level wildlife and in humans. Accordingly, pure authentic reference standards have been required to promote high quality exposure assessments of wildlife and humans and analysis of abiotic matrices, to study both chemical and physical properties of the PBDEs and to allow toxicological studies. The objective of this thesis was to develop methods for synthesis of polybrominated diphenyl ether (PBDE) congeners and to characterize them. Further, some octabrominated DEs were determined with x-ray crystallography. Main focus has been to prepare highly brominated PBDE congeners, i.e. PBDEs substituted with six to nine bromine atoms. A total number of twenty-three PBDE congeners were synthesized via reduction of decabromodiphenyl ether receiving nonaBDEs; perbromination and bromination of mono- and diaminodiphenyl ethers followed by diazotization of the amino group(s) and reduction of the diazonium ion(s) receiving octaBDEs and nonaBDEs; selective bromination of diaminodiphenyl ethers followed by diazotization of the amino groups and insertion of bromine receiving hexaBDEs and heptaBDEs; bromination of the latter PBDEs giving octaBDEs; and an improved coupling of symmetrical diphenyliodonium salts with bromophenols yielding tetraBDEs to octaBDEs. To enable these compounds to be synthesized three hexabromodiphenyl iodonium salts were prepared: 2,2’,3,3’,4,4’-, 2,2’,4,4’,5,5’- and 2,2’,4,4’,6,6’ - hexabromodiphenyliodonium salts. These iodonium salts are described for the first time which made it possible to synthesize PBDE congeners with 2,3,4-, 2,4,5- and 2,4,6-tribromo substitution in the phenyl rings originating from the diphenyliodonium salts. Among the PBDE congeners 18 are synthesized for the first time. The thesis includes an improved methodology for synthesis of polybromodiphenyl iodonium salts which is based on improved solubilization of both one of the reactants and the product formed. The present work on PBDE synthesis adds useful methods for synthesis of the most highly brominated diphenyl ether congeners.

Adding chemicals to materials to decrease flammability can be dated back to as early as 450 BC when the Egyptians used alum to reduce flammability of wood. Almost 2500 years later brominated flame retardants (BFRs) are used to prevent ignition of textiles, electronics and polymers. BFRs in major use today are polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCDD) and tetrabromobisphenol A (TBBPA), including derivatives. There have been three industrial PBDE mixtures produced. Extensive scientific reporting has shown increasing concentrations of PBDEs in wildlife and in humans. This in combination with reports on their physico-chemical characteristics and chemical reactivity have led to that two of the PBDE products have been classified as being persistent, bioaccumulative and toxic, which has led to legislative measures, in e.g. EU, Norway and the USA. The availability of pure reference standards is a prerequisite for much toxicologically related research. Hence the main objective of this thesis was to develop additional methods for synthesis of highly brominated diphenyl ethers. Further, to quantify and identify photolysis products of decabromodiphenyl ether (decaBDE) and to perform a case study regarding PBDE exposure in aircrafts. Synthesis of highly brominated BDE congeners by perbromination of mono- or diaminodiphenyl ethers followed by diazotization of the amino group(s) and introduction of hydrogen(s) in the molecules is a convenient route for synthesis of some octaBDEs and all nonaBDEs. Selective bromination of diaminodiphenyl ether, followed by diazotization of the amino groups and substitution with bromines yielded a hexaBDE or a heptaBDE which were then further brominated to octaBDE congeners. Even though several studies have been performed on photolysis of decaBDE a new study with a more quantitative approach was performed as part of this thesis. Debrominated PBDE products were identified and quantified and a marker PBDE for UV degradation of DecaBDE was identified i.e., 2,2’,3,3’,5,5’,6,6-octabromodiphenyl ether (BDE-202). Polybrominated dibenzofuranes, methoxlated brominated dibenzofuranes, pentabromophenol and hydroxylated bromobenzenes were also detected. The PBDEs accounted for approximately 90% of the total amount of substances in each sample and the PBDFs for about 10%. Also, a case study on potential exposure to PBDEs in humans travelling long distances by aircraft was done. It was shown that PBDE concentrations in dust onboard aircrafts may be high and increased PBDE serum levels were indicated in a majority of the travellers. The present thesis has contributed to make higher brominated diphenyl ethers available as reference standards, allowing better quantitative assessments possible regarding both abiotic studies and exposure assessments. New toxicological testing can also be pursued.

Acrylamide is formed in heat processing of many common foods. According to animal cancer tests acrylamide is a carcinogen. To estimate the cancer risk from exposure via food, the response at high doses in the cancer tests with rats has to be extrapolated to the exposure levels in humans. Acrylamide is biotransformed to the epoxide glycidamide, which is assumed to be the cancer-risk increasing agent. Therefore in vivo doses of both acrylamide and glycidamide should be measured in rats and humans and related to the acrylamide intake. In vivo doses (area under the time-concentration curve, AUC) of reactive compounds can be determined from measured reaction products, adducts, to hemoglobin (Hb). A study in mice showed that the food matrix does not have an influence on the absorbed amount of acrylamide from food. There was a linear dose-response of Hb-adduct levels from acrylamide and glycidamide. For cancer risk assessment it is important to describe variations between individuals in intake and in AUC. Hb-adduct levels of acrylamide and glycidamide were studied in two large groups. In non-smokers the acrylamide and glycidamide-adduct levels varied with a factor of 5 and 8, respectively. The influence of other compounds in the diet on metabolic formation/elimination of glycidamide was demonstrated by associations between the ratio of glycidamide-to-acrylamide-adduct levels and alcohol intake. Furthermore, a non-linearity between glycidamide and acrylamide-adduct levels was shown at low exposure levels. AUCs from acrylamide and glycidamide in rats exposed as in the cancer tests were measured and compared with AUCs in humans exposed to acrylamide through food. The AUC of glycidamide per given dose of acrylamide was somewhat higher in humans than in the rats. Altogether the generated data could be used to improve the cancer risk estimate of acrylamide in food. The obtained data strengthen earlier preliminary cancer risk estimates of acrylamide. / At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 4: Manuscript. Paper 5: Manuscript.

In countries located in tropical zones, a critical task in drinking water plants is the removal of the natural organic matter (NOM), particularly during the rainy season when a lot of organic matter is transported by run-off into the water bodies. It provokes overloaded in the plants and they have often needed to be shut down. In the dry season, the NOM removal is also difficult due to its low concentration, and greater coagulant dosages are needed to destabilize the negative charge of the NOM. In order to increase the NOM removal, synthetic polymers based on acrylamide are sometimes used as coagulant aids. However, they have been associated with Alzheimerand are carcinogenic. Therefore, the present requirement is to find new treatments affordable for the conditions existing in tropical countries. The application of green compounds has become a responsibility to guarantee the health of the population. The situation in Nicaragua is similar to that in many tropical countries. At present, there are ten drinking water plants which use conventional treatment. Nine of them use surface water supplied by rivers, and one uses water from a lake. Many of these plants have problems of continuity, quantity, water quality, and coverage, although the water cost is low. The removal of natural organic matter by conventional or enhanced coagulation using aluminium sulphate or chitosan as coagulant while reducing the formation of trihalomethanes (THM) was the aim of this work. Chitosan is an environment-friendly compound that can act as coagulant, flocculant and adsorbent. Adsorption with activated carbon and chitosan has also been studied. The natural organic matter in the source waters was fractionated in order to determine which fractions are removed more easily by coagulation and which are recalcitrant. The experimental works was carried out with a period of sampling between 2003 and 2010, taking into consideration the dry and rainy seasons. The results show that conventional coagulation with aluminium sulphate is not sufficient to reduce the presenceof NOM sufficiently to avoid a high level of THM in the disinfection step. The NOM removal is greatly improved by treatment with enhanced coagulation, but a significant amount of NOM is not removed, with a high THM concentration as a consequence. High NOM removal can however be achieved by enhanced coagulation and subsequent adsorption with granular activated carbon. Chitosan has good properties as a coagulant in water with a high NOM content and performs well as flocculant. It also has a high adsorption capacity for NOM. Therefore, chitosan could be a good option as a substitute for aluminium sulphate compounds. However, since chitosan does not work properly in the dry season, when the NOM content is low, the use of aluminium sulphate in combination with chitosan should bestudied in more detail. A field with a large potential is the modification of the chitosan structure to increase its capacity for NOM removal and decrease the need for aluminium sulphate. Another advantage of using chitosan is the reduction of the negative impact of shrimp and squat lobster shells on the environment. / QC 20110215

In order to assess the risks that are associated with a deep repository of nuclear waste, it is important to know how different radionuclides behave in different environments. Since some of the most critical radionuclides in nuclear waste such as Ra-226 occur naturally in the environment, it is possible to study their behaviour directly. Peat lands are thought to be one of the most critical ecosystems due to their capability of accumulating large amounts of radioactivity and the possible exposure pathways to man. Klarebäcksmossen is a peat land situated close to the nuclear power plant in Oskarshamn, which is one of two areas in Sweden where site investigations for a future deep repository are being conducted. In this study a complete peat-gyttja-clay profile from Klarebäcksmossen has been analysed for a large number of both natural and artificial radionuclides using gamma spectrometry. The degree of isotopic disequilibrium between different nuclides in the uranium-thorium series has been used to assess radionuclide migration and accumulation throughout the core. The measurements indicate that uranium has been accumulated in the gyttja, but mobilised from the clay. Radium, on the other hand, has been leached from the gyttja layers, and the strikingly low Ra-226/Pb-210 ratios show that it might have been very recently. Alternatively, there is a very extensive migration of Rn-222. In the peat low levels of radioactivity were found for most radionuclides, but with clear differences between minerotrophic and ombrotrophic peat. This may indicate that the uptake of radionuclides by peat mainly is passive. The accumulation rate for the peat has also been determined using Pb-210 dating.

The purpose of this study was to develop the on-line method of analysis which leads to the study of polycyclic aromatic hydrocarbons (PAHs) during combustion in an atmospheric fluidized bed combustor (AFBC) system. The study of PAHs is important because they may be produced upon the combustion of coal. The US EPA prioritizes PAHs as major pollutants due to their mutagenic and carcinogenic effects. Standards of PAHs were analyzed by injection into the gas chromatograph-mass spectrometer (GC-MS). These standards were then analyzed using the on-line method. Two coals were burned in the AFBC system and effluent samples were collected. These were analyzed with the GC-MS to see if there were any PAHs or chlorobenzenes present.

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.

Perfluoropolyethers (PFPEs) are used in a remarkably large number of industrial applications including thin-film lubricants, greases, heat transfer fluids, cosmetics, and EPA-approved food contact paper coatings and are marketed for their chemical inertness. Although desired industrially, it is also the property of most environmental concern. The lack of literature concerning the environmental impact of these compounds suggests a need to assess and characterize their environmental fate and transport. This work describes efforts to develop methods to characterize, identify and quantify various congeners of PFPEs through chromatographic, mass spectral and nuclear magnetic resonance techniques. The PFPEs exhibited unusual behavior during ionization by ESI, suggesting the possibility of structural lability during analysis. A preliminary assessment of the environmental degradation of a PFPE-phosphate congener is also described, which showed rapid sorption to sewage sludge particulate matter and the possible presence of multiple PFPEs present in the technical product mixture used for analysis.