This thesis is focused on studies on the environmental fate and methodological improvements for determination of the global contaminants, PCBs and DDTs, and locally discharged phenolics, e.g. 4,5,6-trichloroguaiacol (4,5,6-TCG), and their transformation products. 4,5,6-TCG is released from bleached pulp mills, and was chosen as a model substance, to study its fate and effects in aquatic environments. In a brackish water model ecosystem, 4,5,6-TCG was shown to be transformed via demethylation, dechlorination, and methylation reactions. Marine periphyton exposed to 4,5,6-TCG was shown to form demethylated, brominated and dimeric metabolites. Several of these metabolites were identified and quantified. Also more tightly bound chlorophenolics were recovered from the substrate, after harsh extraction procedures had been applied. Conjugates of chlorophenols in fish bile were determined as useful tracers for monitoring effluents from bleached pulp mills, even in areas far from the discharge point. To facilitate calculations of water concentrations, bile to water bioconcentration factors (bBCF-values) were determined for several phenolics, including also alkali-labile chlorocatechols. PCBs and DDTs, were assessed in Swedish lakes with background exposure of these global contaminants. A methodological study focus on the contamination risks of airborne PCBs, during freeze-drying and storage of dry sediment samples. Eutrophication has been proposed to cause lower levels of pollutants in biota in lakes due to biomass dilution but in this thesis examples of higher levels of PCBs in sediment traps, sediment and in perch, and also in higher fluxes of PCBs to the sediment, were observed. Phytoplankton are supposed to be responsible for most of the transport of the contaminants. The composition of DDTs in soil, sediment traps and in dated sediment cores was studied in some detail. PCBs, DDTs, HCB and HCHs were measured in sediments from 100 reference lakes included in the National Swedish Environmental Program. The lakes have a large variation in lake characteristics, representative for different areas in Sweden. A gradient was observed for sPCB with decreasing levels from the south west towards the north. The results suggests that longrange transport is the dominating mechanism for distribution of the contaminants analysed. In this study the levles of PCBs and DDTs were lower in eutrophic lakes than in oligotrophic lakes, in an area with similar atmospheric exposure. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 4: Submitted. Paper 6: Manuscript.</p>

Does the active membrane transporter, Na+,K+-ATPase dimerize? If it does, whatis the functional benefit? Does it increase or decrease the turnover rate? Theseare still unanswered questions and current research topics. Previous studies havedemonstrated dimerizations in closely related proteins of the P-type ATPase family.For the Na+, K+-ATPase a first indication of dimerization has been shown viaFluorescence lifetime imaging microscopy (FLIM) or Fluorescence resonance energytransfer - Fluorescence correlation spectroscopy (FRET-FCS) experiments. Theprecise dimer structure, dimerization process, and its ultimate functional effecthowever, remain to be found. This master thesis approaches those questions froma co-evolutionary standpoint. It predicts a possible dimer structure by starting with amultiple sequence alignment, direct coupling analysis, and structural contact filteringalgorithm. This model would strengthen the dimerization model of a decreasedturnover rate due to a competitive behavior of two Na+, K+-ATPases for its energysource ATP. / Dimeriserar den aktiva membrantransporten Na+,K+-ATPas? Om den gör det,vad är den funktionella nyttan? Ökar eller minskar det omsättningshastigheten?Dessa är obesvarade frågor och rådande forskningsämnen. Tidigare studier hardemonstrerat dimeriseringar i nära relaterade proteiner av P-typ ATPas-familjen.För Na+, K+-ATPas har en första indikation av dimerisering visats via ”Flourescencelifetime imaging microscopy (FLIM)” eller ”Flourescence resonance energy transfer- Flourescence correlation spectroscopy (FRET-FCS)”. Den precisa dimerstrukturen,dimeriseringsprocessen och dess slutgiltiga funktionella effekt emellertid, återståratt ses. Detta examensarbete på masternivå närmar sig dessa frågor från ettsamevolutionärt perspektiv. Det förutser en möjlig dimerstruktur genom att utgåfrån en flersekvenslinjering, direkt kopplingsanalys och en strukturell kontaktfiltreringsalgoritm. Denna modell skulle stärka dimeriseringsmodellen av minskadomsättningshastighet till följd av tävlingsbeteende mellan två Na+,K+-ATPaser fördess energikälla ATP.