Mycobacterium avium and Mycobacterium intracellulare are environmental opportunistic pathogens whose source for human infection is water and soil. M. avium and M. intracellulare cause pulmonary infections (tuberculosis) in immunocompetent individuals and bacteremia in immunodeficient individuals (e.g. AIDS). One factor likely influencing the lack of success of antibiotic therapy in patients would be their ability to form biofilms. Growth in biofilms might result in antimicrobial resistance because (1) cells are protected by layers of other cells and extracellular material (2) and differences in physiologic state of cells as a consequence of growing on surfaces. The objectives of the work were to (1) establish methods for reproducible growth of mycobacterial biofilms (2) measure the formation of biofilms on surfaces by cells of M. avium and M. intracellulare (3) measure the antibiotic- and chlorine- susceptibility of M. avium and M. intracellulare strain TMC1406T in cell grown in suspension, cells grown in biofilms and suspended and of cells grown in biofilms (4) measure the hydrophobicity of M. avium and M. intracellulare grown in suspension and in biofilms. Methods were developed for growing mycobacteria in biofilms in polystyrene flasks and on glass beads. Although both strains formed biofilms, M. intracellulare strain TMC 1406T more readily formed biofilms than M. avium strain A5 in polystyrene flasks. The majority of M. intracellulare strain TMC 1406T cells grew on the walls of the flasks rather than in suspension like M. avium strain A5. The susceptibility of M7H9 medium-grown cells of M. avium strain A5 and M. intracellulare strain TMC 1406T cells grown in suspension, cells grown in biofilms and suspended and cells grown in biofilms was measured against clarithromycin, ethambutol, kanamycin, rifampicin and streptomycin. Cells grown in biofilms and exposed to antibiotics in biofilms were five-fold resistant to antibiotics than were cells grown in biofilms and exposed in suspension. Cells grown and exposed in suspension were ten-fold more sensitive to antibiotics than were cells grown in biofilms and exposed in suspension. The chlorine susceptibility of cells grown in medium and water was also measured. Cells grown in biofilms were more resistant to chlorine than cells grown in biofilms and suspended. Cells grown in suspension were more sensitive to chlorine than cells grown in biofilms and suspended. The hydrophobicity data (i.e., hexadecane adherence and contact angle measurements) showed that cells grown in biofilms are more hydrophobic than cells grown in biofilms and suspended and cells grown in suspension. It is clear that there are physiological changes between cells grown in suspension, cells grown in biofilms and suspended and cells in biofilms. / Master of Science

No description available.

No description available.

This thesis deals with the urgent and follow-up measures in case of chlorine leak and a retrospective analysis of past cases. Chlorine is a widely used toxic gas. It is known from history as the first practically used warfare agent. Today, it is an important chemical raw material that is used widely in industry. It is also commonly transported by road and rail. It is one of the substances whose leakages occur very often. The objective of this paper is to assess the impacts of chlorine leakage on the lives and health of people and to provide an overview of urgent and follow-up measures in case of chlorine leakage in the perspective of the integrated rescue system and the general public. In addition, to locate, describe and analyze past cases. The theoretical part contains information about chlorine, the principles of behaviour of the population in case of an accident with chlorine leakage and an overview of measures undertaken at the site of chlorine leakage. Through studying available literature and resources on the Internet, overview of major chlorine leakages in the Czech Republic as well as abroad has been created. Selected events are described in detail. The practical part simulates, using computer programme called TerEx, a chlorine leakage from a water treatment plant in Písek, South Bohemia. To compare the results, several model situations were created with varying amounts of chlorine leaked at different times of accident and atmospheric conditions. A specific example is used to assess the risks to people living near the plant and to outline the urgent and follow-up measures.

Disinfection is an essential process in the treatment of municipal wastewater before the treated wastewater can be discharged to the environment. Hillsborough County's Northwest Regional Water Reclamation Facility (NWRWRF) in Tampa, Florida, currently uses ultraviolet (UV) light for disinfection. However, this method has proven expensive to implement and maintain, and may not be effective if the light transmission is poor. For these reasons, Hillsborough County is considering switching from UV light to sodium hypochlorite for disinfection. However, hypochlorite (chlorine) disinfection has disadvantages as well, such as the production of disinfection by-products (DBPs) such as trihalomethanes (THM) and haloacetic acids (HAAs), which may have adverse impacts on the quality of surface waters that receive the treated wastewater. Therefore, the objectives of this research are (1) to compare NWRWRF typical operating conditions and water quality to those of two nearby facilities (River Oaks and Dale Mabry Advanced Wastewater Treatment Plants) that currently employ chlorine disinfection, (2) to determine the chlorine demand of treated effluent from NWRWRF, (3) to quantify the DBP formation potential of treated effluent from NWRWRF, and (4) to determine the effects of temperature, reaction time, and chlorine dose on chlorine demand and THM formation. To inform laboratory experiments, the quality of final effluent was monitored at NWRWRF and at two nearby wastewater treatment plants that currently use hypochlorite for disinfection. At these two facilities, pH of 7.0-8.0, chemical oxygen demand (COD) of 12-26 mg/L, alkalinity of 200-250 mg/L as CaCO3, chlorine residual of 1.5-6.0 mg/L, and total trihalomethanes of 100-190 ix μg/L (mostly chloroform) were observed. Conditions at NWRWRF were similar to those at Dale Mabry and River Oaks AWWTP, suggesting that chlorine demand and THM formation at NWRWRF would be similar to those at the two AWWTP, if chlorination is to be used. THM experimental results agreed with this suggestion. Chlorine dose and temperature effects on the free chlorine residual and THMs production in NWRWRF filtered wastewater effluent were determined. Filtered effluent was collected and transported to USF laboratory where it was tested for 3 different chlorine doses (6 mg/L, 9 mg/L and 12 mg/L as Cl2) and 3 different temperatures (16°C, 23°C, and 30°C) at 7 different contact times (15, 30, 45, 60, 75, 90, and 120 min) in duplicate. The total number of batches prepared was: 3 different chlorine doses × 3 different temperatures × 7 different reaction times = 126 reactors. According to Florida Administrative code 62-600.440, total chlorine residual should be at least 1 mg/L after a contact time of at least 15 min at peak hourly flow. Also, according to Florida Administrative code 62-600.440, if effluent wastewater has a concentration of fecal coliforms greater than 10,000 per 100 mL before disinfection, FDEP requires that the product of the chlorine concentration C (in mg/L as Cl2) and the contact time t (in minutes) be at least 120. Results showed that free chlorine residual was always above 1 mg/L in 15 min contact time for all chlorine doses and temperatures tested in this thesis. However, to be conservative, thesis conclusions and recommendations were based on the more stringent regulation: C*t ≥ 120 mg.min/L, assuming that the number of fecal coliform in NWRWRF wastewater effluent exceeds 10,000 per 100 mL prior to disinfection. The analysis showed that free chlorine residual for 6 mg/L was below the FDEP standard at all temperatures. At 16 °C and 23 °C, chlorine doses of 9 and 12 mg/L resulted in an appropriate free chlorine residual above the FDEP standard. However, a chlorine dose of 12 mg/L was resulting in high residual, which means high THM would be expected. Therefore, at 16 x and 23°C, 9 mg/L would be preferable. At 30 °C, only the chlorine dose of 12 mg/L met the standard at all contact times. As expected, free chlorine residual decreased with an increase in temperature from 23°C to 30°C. Surprisingly, the residual at 16°C was lower than residual at 23°C. The production of THMs increased with higher contact time in all the experiments completed. Chlorine dose didn't have an effect on THM formation at 23°C, but it did at 30°C and 16°C, where THM concentrations were generally higher with the increase of chlorine dose. Temperature effect was noticed in most of the experiments, where THM production was usually higher at higher temperatures, except some cases where formation was similar for different temperatures. Chloroform, dichlorobromomethane, dibromochloromethane production ranges were respectively: 20-127 μg/L, 18-59 μg/L, and 3-7 μg/L. Bromoform concentrations were not observed in this experiment at any temperature or chlorine dose. According to Florida Administrative code 62-302.530, Criteria for Surface Water Quality Classifications, the Florida Department for Environmental Protection (FDEP) set the following limits for THM concentrations in wastewater effluent to be as the following; 470 μg/L for chloroform, 22 μg/L for dichlorobromomethane, 34 μg/L for dibromochloromethane, and 360 μg/L for bromoform. Experimental results on NWRWRF filtered effluent showed that only dichlorobromomethane exceeded the limits set by FDEP at about 30 min contact time for all temperatures and chlorine doses tested. However, according to Florida Administrative code 62- 302-400, proposed changes to the code have set higher DCBM limit of 57 μg/L. Chlorination would be recommended at NWRWRF if the DCBM regulated limit increases to 57 μg/L. The recommended chlorine dose would be 9 mg/L for water temperatures around 16-23 °C and 12 mg/L for water temperatures around 30 °C

The diploma thesis deals with the rate of free chlorine dacay in the water supply systems. In the general part of the work are mentioned the forms of chlorine that can be encountered in its use for disinfection of drinking water. Another chapter is the modeling of chlorine decomposition in water during pipeline distribution. This chapter deals with the kinetic reactions of chlorine and their orders, and subsequently with factors influencing the rate of chlorine loss. Closer deals with pipe wall chlorine decay and the bulk water flow chlorine decay. The second part of the diploma thesis is focused on determining the constant kb, which is the rate coefficient of loss of chlorine in the pipeline caused by the flow of water. The work contains several researches of various world studies that deal with this issue. The following is a step-by-step guide to performing this test. The last part deals with the case studies at the waterworks in Kateřinice and Brno. On these tapes the chlorine concentration was measured over time and a constant kb was determined based on these results, expressing the rate of free chlorine decay in bulk water flow.

Thesis (MScMedSc (Pathology. Medical Microbiology))--University of Stellenbosch, 2009. / Water is used for various purposes and contamination can have severe implications if untreated. One of the most common and cost effective water disinfectants, especially used in developing countries, is chlorine. However, microorganisms have developed different mechanisms in response to environmental stress conditions, such as the viable but nonculturable (VBNC) effects possibly displayed in this study, enabling them to survive. Chlorine may also exert several effects on microorganisms, such as the expression of multi-substrate efflux pumps, decreased membrane permeability and transport inhibition that may lead to chlorine tolerance and antimicrobial resistance. In a descriptive and comparative study, the molecular characteristics of E. coli strains isolated from environmental waters in the Western Cape and the possible relationship between chlorination and antimicrobial resistance were investigated. Water and biofilm samples were exposed to chlorine, as well as efflux pump inhibitor (EPI) concentrations, and surviving E. coli strains were tested for their phenotypic characteristics including antimicrobial susceptibility profiles and morphological types. Candidate genes possibly involved in resistance to antimicrobials, disinfection and efflux pumps were detected with polymerase chain reaction (PCR) and sequenced. Sequencing analysis and homology searches were done and E. coli strains were typed as either Enteropathogenic E. coli strains (EPEC) or Enterotoxigenic E. coli strains (ETEC) on the presence of virulence genes. All water and biofilm sources examined were heavily polluted with E. coli, and a high enumeration level of this indicator organism of faecal contamination was recorded. Chlorine tolerance was found to be associated with antimicrobial resistance. Addition of EPI with exposure to chlorine decreased enumeration levels of these organisms, suggesting that efflux pumps may play a role in tolerance to chlorine. Several morphological patterns were described amongst the E. coli strains and a change in this was recorded after exposure to chlorine. Highly resistant antibiograms displayed by the isolated strains included ampC β-lactamase producing E. coli strains and extended spectrum β-lactamases (ESBLs). Amplification of the candidate genes selected for heatshock, oxidative stress genes and efflux pump were most frequently detected while the structural genes involved in fluoroquinolones (FQs) resistance were detected less frequently in the selected strains. Sequencing of these amplified candidate genes demonstrated various changes in amino acid sequences, including one common mutational pathway taken by E. coli when exposed to stress conditions. Further homology searches of the sequenced candidate genes illustrated similarities in 19 pathogenic and 14 non-pathogenic E. coli as well as 3 Shigella strains. Detection of virulence genes found three EPEC strains (bfpA, eaeA), two EPEC (eaeA), ten EPEC (bfpA) and one ETEC strain (st) amongst the isolates. This study underlines the need for monitoring our water sources, which poses a public health risk due to incomplete chlorination, antimicrobial resistance and the spread of clinically relevant pathogenic strains.

A presença de resíduos de fármacos em águas superficiais e de abastecimento público tem preocupado a comunidade científica devido principalmente à sua persistência na água e aos efeitos adversos causados à comunidade aquática e aos possíveis riscos à saúde humana. Dentre os fármacos comumente identificados em águas de abastecimento público, encontram-se os anti-inflamatórios, como o diclofenaco (DCF), um dos fármacos mais consumidos no Brasil e no mundo. Nesse contexto, o presente trabalho, teve como objetivo principal estudar a eficiência das etapas de tratamento de água em ciclo completo (coagulação, floculação, sedimentação, filtração em areia e desinfecção com cloro) com e sem pré-oxidação com cloro e com dióxido de cloro e adsorção em carvão ativado granular (CAG) na remoção de DCF. Também foram determinados os trialometanos (THM) e identificados os principais subprodutos do DCF formados na oxidação com cloro e dióxido de cloro. Para a determinação do DCF nas amostras de água antes e após as etapas de tratamento de água foram desenvolvidos e validados métodos analíticos de extração em fase sólida (SPE) e cromatográfico por cromatografia líquida de alta eficiência (HPLC) com detecção no ultravioleta (UV). A validação do método foi feita de acordo com a resolução n&ordm; 899 de 2003 da Agência Nacional de Vigilância Sanitária (ANVISA), considerando os requisitos para métodos bioanalíticos. Os procedimentos analíticos empregados foram efetivos e confiáveis para a identificação e quantificação do DCF nas amostras de água antes e após os processos de tratamento de água. Os ensaios de tratamento de água foram feitos em equipamento de reatores estáticos (jarteste) e filtros de escala laboratorial empregando-se água de poço artesiano não clorada preparada com substâncias húmicas aquáticas (SHA) para conferir cor verdadeira de 20 uH, caulinita para conferir turbidez de 70 uT e fortificada com 1 mg L-1 de DCF. Os resultados indicaram que as etapas de coagulação com sulfato de alumínio, floculação, sedimentação e filtração em areia não removeram o DCF. Nas etapas de préoxidação com cloro e dióxido de cloro e de pós-cloração houve remoção parcial do DCF, porém verificou-se a formação de subprodutos provenientes da oxidação do DCF. Dentre os THM, foi quantificado apenas o clorofórmio na etapa de pré-oxidação com cloro. Em geral, os resultados indicaram que o dióxido de cloro foi mais eficiente na redução do DCF e formou menos subprodutos. Entretanto, o tratamento em ciclo completo seguido da adsorção em CAG foi eficiente na remoção de DCF, com remoção maior que 99,7%. Os subprodutos formados na oxidação com cloro e dióxido identificados por cromatografia líquida acoplada a espectrometria de massas em série (LC-MS/MS) consistiram na descaboxilação/hidroxilação e substituição aromática de átomos de hidrogênio por cloro. Os subprodutos identificados na oxidação com cloro apresentaram as seguintes fórmulas moleculares: C14H11</subCl2NO3, C13H10Cl3N e C14H10Cl3NO2. Com o dióxido de cloro foi identificado o subproduto de fórmula molecular igual a C14H11Cl2NO3. / The presence of pharmaceutical residues in surface waters and in drinking water supply has concerned the scientific community, mainly in which regards their persistence in water, adverse effects on the aquatic community and possible risks to human health. Antiinflammatory drugs, as diclofenac (DCF), are among those drugs commonly identified in drinking water supply. In this context, the main objective of this study was to assess the efficiency of the different stages of the conventional drinking water treatment (coagulation, flocculation, sedimentation, sand filtration and chlorine disinfection) with and without preoxidation with chlorine and chlorine dioxide and adsorption on granular activated carbon (GAC) in the removal of DCF. The trihalomethanes (THMs) were also determined and the main by-products of DCF formed by oxidation with chlorine dioxide and chlorine were identified. For the DCF determination in water samples before and after water treatment stages analytical methods of solid phase extraction (SPE) and chromatographic method by high performance liquid chromatography (HPLC) with detection in the ultraviolet (UV) were developed and validated. The method validation was based on Resolution n&ordm; 899 of the 2003 of the Brazilian National Health Surveillance Agency (ANVISA), considering the requirements for bioanalytical methods. The analytical procedures used were effective and reliable for the identification and quantification of DCF in the water samples before and after the water treatment stages. The water treatment tests were carried out in jar test equipment and filters on laboratory scale employing non chlorinated water of artesian well prepared with aquatic humic substances (AHS) to yield 20 uH true color, kaolin turbidity of 70 NTU and DCF concentration of 1 mg L-1. The results indicated that the stages of coagulation with aluminum sulphate, flocculation, sedimentation and filtration sand did not remove DCF. In the stages of pre-oxidation with chlorine and chlorine dioxide and chlorine disinfection the DCF was partially removed, however by-products were formed from the DCF oxidation. Among the THMs, only chloroform was quantified in the pre-oxidation with chlorine. In general, the results showed that chlorine dioxide was more effective to reduce the DCF and fewer by-products were formed. Nevertheless, the complete cycle treatment followed by GAC adsorption was effective to remove DCF (&gt; 99.7%. removal). The by-products of the oxidation of DCF with chlorine and chlorine dioxide identified by liquid chromatography coupled tandem mass spectrometry (LC-MS/MS) consisted in the descaboxylation/hydroxylation and aromatic substitution of hydrogen atoms by chlorine. The compounds identified in the oxidation with chlorine showed the following molecular formulas: C14H11</subCl2NO3, C13H10Cl3N e C14H10Cl3NO2. The by-product identified using chlorine dioxide was C14H11Cl2NO3.

No Brasil, a desinfecção e oxidação da água, para o consumo humano, são usualmente realizadas com a adição de cloro nas formas de gás cloro e hipoclorito de sódio. Estudos recentes tem demonstrado que a oxidação e desinfecção da água com o cloro podem ocasionar a formação de trialometanos e outros subprodutos clorados. Alguns destes subprodutos são substâncias carcinogênicas. Neste trabalho estudou-se a influência das substâncias húmicas (SH) extraídas da turfa, com diferentes massas moleculares, na formação de trialometanos e outros subprodutos clorados em decorrência do uso do cloro e dióxido de cloro na etapa de oxidação da água. As frações das SH utilizadas neste trabalho foram caracterizadas por análise elementar, ultravioleta visível, ressonância magnética nuclear de C13 (RMN de C13), ressonância paramagnética nuclear eletrônica (EPR) e infravermelho. Estas caracterizações demonstraram que a fração de menor massa molecular (30-100 KDa), obtidas por ultrafiltração (UF), apresentou um menor grau de condensação de grupamentos aromáticos em relação as frações de SH de massa molecular menor que 0,45 &#956m e maior do que 100 KDa. Nas análises realizadas por RMN de C13 e análise elementar, constatou-se que a fração de SH de massa molecular entre 30-100 KDa, apresentou uma maior porcentagem de grupos contendo oxigênio. Após as caracterizações das SH, preparou-se três tipos de água, com cor 100 +/ - 5 uH, adicionando-se as diferentes frações de SH na água separadamente. A seguir foram realizados ensaios no equipamento jarteste, para a determinação das dosagens dos oxidantes cloro e dióxido de cloro os quais foram utilizadas nos ensaios de formação dos subprodutos clorados. Estes ensaios foram realizados variando-se as dosagens do oxidante em função do tempo de reação. As concentrações dos oxidantes determinadas foram de 7,0 mg/L para o cloro e de 1,0 mg/L para o dióxido de cloro. Na realização dos ensaios de formação dos subprodutos clorados, considerou-se o tempo de reação em função da dosagem dos oxidantes cloro e dióxido de cloro que foram determinadas anteriormente nos ensaios de demanda. Os subprodutos clorados, formados, foram quantificados utilizando-se a técnica de cromatografia gasosa com detector de captura de elétrons. O método utilizado foi o do padrão interno. O clorofórmio foi o subproduto majoritário, nos ensaios realizados com todas as frações. Na oxidação da água com o cloro, ocorreu a formação de um maior número de subprodutos clorados em relação aos ensaios realizados com oxidante dióxido de cloro. Nos ensaios realizados com a água preparada com SH de menor tamanho molecular ocorreu uma maior concentração dos subprodutos clorados formados, especialmente para o clorofórmio. / In Brazil, the disinfection and oxidation of drinking water is usually done by the addition of chlorine gas and sodium hypochloride forms. Recent studies have demonstrated that disinfection and oxidation of water using chlorine can cause the formation of trihalomethane and others chlorine by-products, which are carcinogenic substances. In this present work, it has been studied the influence of the humic substance (SH) extracted from peat soil, with different molecular size, in the formation of trihalomethane and others chlorine by-products as results of the use of chlorine and chlorine dioxide in the water oxidation step. The SH fractions used in this were characterized by elemental analysis, visible ultraviolet, C13 nuclear magnetic resonance (C13 NMR), electron paramagnetic resonance (EPR) and infrared spectroscopy. Such characterization showed that the fractions with smaller molecular size (30-100 KDa), obtained by ultrafiltration (UF), presented a smaller degree of aromatic groups condensation with respect to fractions of SH molecular size smaller than 0,45 &#956m and higher than 100 KDa. C13 NMR and elemental analysis were also used. SH fraction of molecular size between 30-100 KDa presented higher percentage of groups containing oxygen. After characterizations of SH, water was prepared with 100 +/- 5 uH color, with separated addition of different fractions of SH in the water. Tests in the jartest equipment were realized for the determination of dosages of chlorine and chlorine dioxide oxidants, which were utilized in the test of formation of chlorine by-products. These tests were performed studying the oxidation dosage in function of the reaction time. The oxidant concentrations were 7.0 mg/L for the chlorine and 1.0 mg/L for chlorine dioxide. Formation of chlorine by-products was tested considering the reaction of time with respect to the oxidants dosage of chlorine and oxidant chlorine, previously determined. The chlorine by-products resultant were quantified using the gas chromatography with detector of electron capture technique GC-ECD. The method utilized was the addition of internal standard. In the water oxidation by chlorine an higher number of chlorine by-products occurred in comparison of the test performed with chlorine dioxide. In the test performed with the water prepared with SH of smallest molecular size a highest concentration of resultant by-products occurred, specially by chloroform.

De senaste decenniernas forskning har påvisat att en omfattande bildning och nedbrytning av klororganiska föreningar sker i mark. Bildning av sådana föreningar sker genom att klorid binds in i organiskt material. Denna naturliga bildning har rönt uppmärksamhet dels för att många klorerade ämnen är giftiga och dels för man tidigare trott att alla klororganiska ämnen uteslutande kommer från mänsklig verksamhet. Huvudmålet för föreliggande avhandling var att (i) uppskatta transporten av klorerade föreningar i nederbörd och avrinningsvatten, (ii) diskutera de klorerade föreningarnas ursprung med utgångspunkt från hur deras förekomst varierar i avrinningsvatten, (iii) undersöka hur transporten av klorid (salt) påverkas av olika faktorer och (iv) studera hur frisättningen av flyktiga klorerade föreningar från mark påverkas av kväve. Avhandlingen bygger på en klorbudget som konstruerats utifrån fältstudier som genomförts i ett litet skogsbeklätt avrinningsområde i sydöstra Sverige. Dessutom har laboratoriestudier genomförts med jord som inhämtats från samma område. Resultaten visar att lagret av klor i marken är betydligt större än flödena och att det främst består av organiska ämnen medan flödet domineras av klorid (salt). Detta tyder på att en stor del av kloriden deltar i en biogeokemisk cykel vilket strider mot gängse uppfattning att klorid rör sig opåverkat genom mark. Hypotesen är att de översta marklagren fungerar som en sänka för klorid genom att omvandlas till organiskt bundet klor. De djupare jordlagren fungerar däremot som en kloridkälla genom att det klorerade organiska materialet transporterats med regnvatten från de ytligare till de djupare liggande lagren för att så småningom brytas ner, varvid klorid frisätts. Ovan beskrivna hypotes stöds av laboratoriestudierna där man kunnat notera att det sker såväl en fastläggning som en frisättning av klorid i mark. Resultaten från avhandlingen tillsammans med resultat från tidigare studier tyder på att en stor del av den klorid som finns i avrinningsvatten kommer från förmultnande organiskt material och att klorid med andra ord inte följer regnvattnets väg genom marken, vilket man tidigare trott. Studierna tyder alltså på att klorid till viss del ”gör en omväg” med en tidsfördröjning på troligen åtskilliga upp till hundratals år. Vidare tyder studierna på att flyktiga klorerade föreningar som kloroform och tetraklormetan bildas i mark och att tillsats av kväve orsakar en minskning av kloroform och en ökning av tetraklormetan. Avhandlingen visar tydligt att det är nödvändigt att rikta uppmärksamhet mot klors biogeokemi i mark och då inte minst mot de processer som påverkar transporten av klor från de övre marklagren till grundvatten och ytvatten om vi ska öka förståelsen av hur klorerade ämnen som tillförts naturen genom mänskliga aktiviteter beter sig. / It is generally known that chlorine compounds are ubiquitous in the environment. In recent years, researchers have concluded that chlorine is part of a biogeochemical cycle in soil involving an interaction between chloride (Clin) and organic-matter-bound chlorine (Clorg). Even though there is indisputable evidence that Clorg is formed naturally, there are actually few simultaneous field measurements of Clorg and Clin. Previously stipulated conclusions with respect to underlying processes and transport estimates have thus been deduced from rather few concentration measurements. It is well known that the chemical composition in soil and runoff water varies widely over time and in space. The main objective of the thesis is to investigate the on-site variation of Clin, Clorg and VOCls in runoff water in order to (i) construct a chlorine budget on a catchment scale to visualize the relative contribution of Clin, Clorg, and VOCls; (ii) more reliably estimate how and why the concentrations of Clin, Clorg, and VOCls in runoff water vary; and (iii) analyze the influence of various environmental variables on the transport. The present thesis highlights the on-site variation and fluxes of Clin, Clorg, and VOCls in a small forested catchment in southeast Sweden. Field flux data collected during a twoyear period and a constructed overall chlorine budget were evaluated. The results show that the storage is dominated by Clorg whereas the transport is dominated by Clin and that the storage is far much larger than the transport. Still, input and output is nearly in balance for all investigated chlorine species. It is interesting to note that these observations resemble observations made for carbon, nitrogen and sulphur; i.e. a large storage, small transport, complex biogeochemical cycling processes at hand but still close to steady state conditions with respect to output-input balances. It appears as if topsoil acts as a sink for Clin, while deeper soil acts as a source of Clin. In addition, the results of the thesis suggest that on-site variation depend on seasonal variations. These variations are to some extent caused by water discharge, but also by water residence time, internal chlorination/dechlorination of organic matter, and different soil water origins. Furthermore, both a net retention and a net release of Clin were observed in laboratory studies. The study indicates that simultaneous retention and release of Clin takes place in soil, which probably has an impact on the Clin import and export fluxes. Finally, the results show for the first time that tetrachloromethane can be emitted from laboratory incubated soil, and that soil nitrogen concentrations has quite different effects on the emission rates of chloroform and tetrachloromethane. The results of the thesis, considered together with results of previous research, suggest that the turnover of chlorine in soils is extensive and potentially important for chlorine cycling in general, which must be taken into account if one wishes to increase the understanding of the cycling of anthropogenic chlorine compounds in the environment. / <p>On the day of the public defence the status of article IV was: Accepted.</p>