Past use of trichloroethylene (TCE) as a degreasing solvent for aircraft maintenance has resulted in widespread groundwater contamination at Air Force Bases around the world. Travis AFB in California and Fairchild AFB in Washington are evaluating phytoremediation as a treatment option, since trees have been reported to take up dissolved TCE from shallow groundwater and volatilize it to the atmosphere while enhancing the volatilization of TCE from surrounding soil. Previous studies generally focused on the identification of removal mechanisms. The emphasis of this research was to quantify total TCE removal from phytoremediation demonstration plots at Travis and Fairchild AFBs. Tree cores, collected using an increment borer and analyzed using headspace GC/MS, were used to determine the relative TCE concentrations within the plume beneath the trees and to estimate the mass of TCE in each tree. To estimate the volatilization of TCE from leaves, a small section of tree branch was placed inside a flow-through glass chamber. Continuous air flow through the chamber maintained normal transpiration and temperature. Air exiting the chamber was sampled for TCE using Tenax® tubes. Humidity probes placed at the chamber entry and exit were used to estimate transpiration. Volatilization of TCE from tree trunk and soil surfaces was measured by enclosing a section of trunk or ground surface within a small stainless steel chamber. Fans in the chamber mixed the air that was recirculated through Tenax® tubes to continuously remove TCE. After a measured time interval, the Tenax® tubes were analyzed for TCE by thermal desorption GC/MS. By using a Thiessen polygon method, the removal of TCE was estimated to be 839 g/yr at Travis and 18 g/yr at Fairchild with the majority from leaf and soil volatilization. Soil surface volatilization of TCE was greater inside the planted areas than outside the planted areas, indicating that the trees enhance this removal by this mechanism. Based on these estimates phytoremediation removed 5 and 50% of the mass of TCE in the groundwater at Fairchild and Travis Air Force sites, respectively.

Enhanced biodegradation using carbon donor and microbial addition is being considered as a possible remediation technique for a trichloroethylene (TCE) contaminated area in Sunset, Utah, west of the source area on Hill Air Force Base. As a precursor to any in situ remediation attempts, several laboratory treatability experiments are being conducted, including the construction of microcosms and flow-through columns. Nine large-scale flow-through columns were built using site groundwater and aquifer material. Bromide tracer tests were conducted to establish and understand the hydraulic conditions within the columns prior to the commencement of the TCE biodegradation experiments. Four predictive models were created to show potential degradation scenarios in the columns and in the field using microcosm data for various system treatments. Treatments selected for modeling indicated that carbon addition alone is insufficient in stimulating dechlorination of TCE. Microbial amendments will be necessary in the column systems when the TCE dechlorination experiments begin.

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<p>Chlorinated aliphatic hydrocarbons (CAH´s) were used widely within dry cleaning facilities and for metal degreasing until their toxicity was discovered. PCE is still used as dry cleaning liquid. Today CAH´s are found in soil environment at places where they have been used in the past. The CAH-concentration in trees growing on contaminated land has quite recently received attention as a cheap and effective way of assessing the extent of a CAH-contamination. The method has however, not been put into use in Sweden.</p><p>The aim of the study has been to investigate whether the CAH-concentration in tree cores could be used to delineate the spread of CAH in a soil environment under Swedish conditions in different seasons. The aim has also been to gain an understanding of the uptake process, as well as to identify the limitations of the method and important issues to consider when sampling.</p><p>Trees were sampled in March and June on Helgö 1:25, 1:26 in Växjö, Småland. Metal degreasing earlier conducted at this site has lead to the CAH contamination of soil and groundwater (PCE, TEC c-DACE). Mostly PCE, TCE, and chloroform were detected in tree cores. The CAH concentration was higher in June. Using the sum of PCE+TCE+c-DCE in trees to delineate the spread gave a result that was quite consistent with a delination done based on groundwater sampling.</p><p>The uptake of CAH by trees is governed by the uptake of water at the root. The water usage, together with the origin of the water used is important for the ability of the tree to take up CAH. The CAH concentration within trees is also dependent on the chemical properties of the compound (Log kow, solubility etc), the concentration of the compound in the soil as well as degradation processeses. The position and height of sampling in the trees, tree species as well as tree size are important factors to consider when sampling. Sampling during summer is preferred when the concentration of CAH in trees is likely to be higher.</p><p>The analysis of CAH in tree cores has potential to be used as a screening tool in soil investigations under Swedish conditions. It is a cheap and easy to use method, which would be a good complement to other investigative measures. However, an increased understanding of the processes involved, together with more analysis are needed., as this is a new method.</p> / <p>Klorerade lösningsmedel (CAH) användes i stor omfattning som bl a kemtvättmedel och avfettningsmedel tills dess att deras toxiska egenskaper blev kända. Perkloretylen (PCE) används än idag som kemtvättmedel. CAH återfinns ofta i markmiljö på de platser där de tidigare använts. Analys av CAH-koncentration i trädkärnor har uppmärksammats som en billig och effektiv metod för att översiktligt bedöma utbredningen av dessa föroreningar. Metoden har inte tidigare använts i Sverige.</p><p>Syftet med detta examensarbete är att undersöka om trädprovtagning kan användas för att bedöma utbredningen av föroreningar i markmiljö under svenska förhållanden vid olika årstider.</p><p>Analyserade CAH-halter i träd har jämförts med tidigare registrerade halter av CAH i grundvatten. Syftet har också varit att beskriva CAH-upptaget i träd, undersöka metodens begränsningar samt att sammanfatta viktiga aspekter vid provtagning.</p><p>Provtagningar av träd har genomförts under mars och juni på fastigheterna Helgö 1:25 och 1:26 i Växjö, där tidigare metallavfettning har medfört att mark och grundvattnet förorenats av CAH; perkloretylen (PCE), trikloretylen (TCE) och nedbrytningsprodukten dikloretylen (c1,2-DCE). Vid analys av trädkärnor detekterades främst PCE, TCE samt TCM (kloroform). Koncentrationen av CAH var högre i juni. Halten PCE+TCE+c-DCE i trädproverna gav en översiktlig bild av föroreningssituationen som överensstämde väl med de grundvattenprover som tidigare tagits på fastigheten.</p><p>CAH tas upp i vattenlöst fas vid trädens rötter. Trädets vattenbehov och vilket vatten det utnyttjar är därför viktigt för dess möjlighet att ta upp CAH. Ämnets kemiska egenskaper (log kow, flyktighet, mm.), samt förekomst och nedbrytning påverkar den halt som registreras i trädet. Vid provtagning bör provtagningspunkternas höjd över marken och position, trädart samt trädstorlek beaktas. Provtagning under sommaren är att föredra eftersom halterna då är högre.</p><p>Jämförelsen med grundvattenprovtagning visar att metoden har potential att användas i Sverige för att bedöma utbredningen av en CAH-förorening i markmiljö. Den är enkel att använda och kan vara ett alternativ på platser där konventionella metoder är svåra att genomföra. En ökad förståelse för involverade processer, samt utökade undersökningar av metoden är nödvändiga då metoden är ny.</p>

Wong Chun-kwan. / Thesis submitted in: December 1999. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 127-137). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgments --- p.viii / Tables of Contents --- p.ix / List of Figures --- p.xv / List of Tables --- p.xxvi / Chapter Chapter 1: --- INTRODUCTION --- p.1 / Chapter Chapter 2: --- LITERATURE REVIEW --- p.8 / Chapter 2.1 --- Toxicology --- p.8 / Chapter 2.1.1 --- Acute toxicity test --- p.8 / Chapter 2.1.2 --- Biochemical Analysis --- p.9 / Chapter 2.1.3 --- Organ weights --- p.10 / Chapter 2.2 --- Histology --- p.11 / Chapter 2.2.1 --- Light Microscope --- p.11 / Chapter 2.2.2 --- Electron Microscopy --- p.11 / Chapter 2.3 --- Tissue injury --- p.12 / Chapter 2.3.1 --- Free-radical mechanisms --- p.12 / Chapter 2.3.2 --- Lipid peroxidation --- p.13 / Chapter 2.4 --- Carbon tetrachloride (CC14) --- p.14 / Chapter 2.4.1 --- Mechanisms of carbon tetrachloride toxicity --- p.15 / Chapter 2.5 --- Trichloroethylene (TCE) --- p.18 / Chapter 2.5.1 --- Mechanisms of trichloroethylene toxicity --- p.21 / Chapter 2.6 --- Dimethyl sulfoxide (DMSO) --- p.25 / Chapter 2.7 --- N-acetylcysteine (NAC) --- p.27 / Chapter Chapter 3: --- MATERIALS AND METHODS --- p.28 / Chapter 3.1 --- Materials --- p.28 / Chapter 3.2 --- Methods --- p.31 / Chapter 3.2.1 --- Acute hepatotoxicity test on aqueous seaweed extracts --- p.31 / Chapter 3.2.1.1 --- Preparation of aqueous extracts of seaweed --- p.31 / Chapter 3.2.1.2 --- Experimental protocol --- p.31 / Chapter 3.2.1.3 --- Biochemical assays --- p.32 / Chapter 3.2.1.4 --- Organ weights --- p.36 / Chapter 3.2.1.5 --- Histopathological examination --- p.36 / Chapter 3.2.1.6 --- Statistical analysis --- p.36 / Chapter 3.2.2 --- Curative and preventive tests of seaweed aqueous extracts against the CCl4-induced hepatotoxicity --- p.37 / Chapter 3.2.2.1 --- Preparation of aqueous extracts of seaweed --- p.37 / Chapter 3.2.2.2 --- Experimental protocol --- p.37 / Chapter 3.2.2.3 --- Biochemical assays --- p.39 / Chapter 3.2.2.4 --- Organ weights --- p.39 / Chapter 3.2.2.5 --- Histopathological examination --- p.40 / Chapter 3.2.2.6 --- Statistical analysis --- p.41 / Chapter 3.2.3 --- Acute hepatotoxicity test of TCE in rats by oral and intraperitoneal routes --- p.42 / Chapter 3.2.3.1 --- Experimental protocol --- p.42 / Chapter 3.2.3.2 --- Biochemical assays --- p.43 / Chapter 3.2.3.3 --- Organ weights --- p.43 / Chapter 3.2.3.4 --- Histopathological examination --- p.44 / Chapter 3.2.3.5 --- Statistical analysis --- p.44 / Chapter 3.2.4 --- Curative and preventive tests of seaweed aqueous extracts against the TCE effective dose-induced toxicity --- p.44 / Chapter 3.2.4.1 --- Preparation of aqueous extracts of seaweed --- p.44 / Chapter 3.2.4.2 --- Experimental protocol --- p.45 / Chapter 3.2.4.3 --- Biochemical assays --- p.46 / Chapter 3.2.4.4 --- Organ weights --- p.46 / Chapter 3.2.4.5 --- Histopathological examination --- p.46 / Chapter 3.2.5 --- Antidotal effects of dimethyl sulfoxide (DMSO) and N-acetylcysteine (NAC) against CC14- and TCE- induced poisoning in rats --- p.47 / Chapter 3.2.5.1 --- Experimental protocol --- p.47 / Chapter 3.2.5.2 --- Biochemical assays --- p.48 / Chapter 3.2.5.3 --- Organ weights --- p.48 / Chapter 3.2.5.4 --- Histopathological examination --- p.49 / Chapter 3.2.6 --- Hepatoprotective effect of seaweeds' methanol extract against CC14- and TCE-induced poisoning in rats --- p.49 / Chapter 3.2.6.1 --- Preparation of methanol extracts of seaweed --- p.49 / Chapter 3.2.6.2 --- Experimental protocol --- p.50 / Chapter 3.2.6.3 --- Biochemical assays --- p.52 / Chapter 3.2.6.4 --- Organ weights --- p.52 / Chapter 3.2.6.5 --- Histopathological examination --- p.53 / Chapter Chapter 4 --- RESULTS --- p.54 / Chapter 4.1 --- Acute hepatotoxicity test on aqueous seaweed extracts --- p.54 / Chapter 4.1.1 --- The biochemical assays of the serum transaminase activity --- p.54 / Chapter 4.1.2 --- The organ weight (Aqueous seaweed crude extracts) --- p.56 / Chapter 4.2 --- Curative and preventive tests of seaweed aqueous extracts against the CCl4-induced hepatotoxicity --- p.58 / Chapter 4.2.1 --- The biochemical assays of the serum transaminase activity (Curative) --- p.58 / Chapter 4.2.2 --- The organ weight (Curative) --- p.60 / Chapter 4.2.3 --- The biochemical assays of the serum transaminase activity (Preventive) --- p.62 / Chapter 4.2.4 --- The organ weight (Preventive) --- p.64 / Chapter 4.3 --- Acute hepatotoxicity test of TCE in rats by oral and intraperitoneal routes --- p.66 / Chapter 4.3.1 --- Oral route --- p.66 / Chapter 4.3.1.1 --- One-time oral route --- p.66 / Chapter 4.3.1.2 --- Two-time oral route --- p.66 / Chapter 4.3.2 --- Intraperitoneal route --- p.66 / Chapter 4.3.3 --- Time course of the effective dose of 20% TCE in i.p. route --- p.67 / Chapter 4.4 --- Curative and preventive tests of seaweed aqueous extracts against the TCE effective dose-induced toxicity --- p.12 / Chapter 4.4.1 --- The biochemical assays of the serum transaminase activity (Curative) --- p.72 / Chapter 4.4.2 --- The organ weight (Curative) --- p.74 / Chapter 4.4.3 --- The biochemical assays of the serum transaminase activity (Preventive) --- p.76 / Chapter 4.4.4 --- The organ weight (Preventive) --- p.78 / Chapter 4.5 --- Antidotal effects of dimethyl sulfoxide (DMSO) and N-acetylcysteine (NAC) against CC14- and TCE-induced poisoning in rats --- p.80 / Chapter 4.5.1 --- The biochemical assays of the serum transaminase activity (Curative) --- p.80 / Chapter 4.5.2 --- The organ weight (Curative) --- p.82 / Chapter 4.5.3 --- The biochemical assays of the serum transaminase activity (Preventive) --- p.84 / Chapter 4.5.4 --- The organ weight (Preventive) --- p.86 / Chapter 4.6 --- Hepatoprotective effect of methanol extract of seaweed against CC14- and TCE-induced poisoning in rats --- p.88 / Chapter 4.6.1 --- The biochemical assays of the serum transaminase activity (Curative) --- p.88 / Chapter 4.6.2 --- The organ weight (Curative) --- p.89 / Chapter 4.7 --- Histopathological examinations --- p.90 / Chapter 4.7.1 --- Acute hepatotoxicity test on aqueous seaweed extracts --- p.91 / Chapter 4.7.2 --- Curative and preventive tests of seaweed aqueous extracts against the CC14-induced hepatotoxicity --- p.92 / Chapter 4.7.3 --- Acute hepatotoxicity test of TCE in rats by oral and intraperitoneal routes --- p.99 / Chapter 4.7.4 --- Curative and preventive tests of seaweed aqueous extracts against the TCE effective dose-induced toxicity --- p.100 / Chapter 4.7.5 --- Antidotal effects of dimethyl sulfoxide (DMSO) and N-acetylcysteine (NAC) against CC14- and TCE-induced poisoning in rats --- p.100 / Chapter 4.7.6 --- Hepatoprotective effect of methanol extract of seaweed against CC14- and TCE-induced poisoning in rats --- p.102 / Chapter Chapter 5 --- DISCUSSION --- p.106 / Chapter Chapter 6 --- CONCLUSION --- p.124 / REFERENCES --- p.127 / APPENDIX --- p.138

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Les récents progrès en matière de nanotechnologies ont permis d'élaborer de nouveaux matériaux aux propriétés physico-chimiques uniques tels que les nanoparticules de fer zéro valent (NPFe0). Ces nanoparticules ont prouvé leur efficacité pour dégrader les composés organiques chlorés comme le trichloroéthylène (TCE), cependant leur transport dans les milieux poreux est souvent limité. Une solution pour pallier à ce problème est de modifier leur surface par adsorption de molécules organiques. Toutefois, cet enrobage modifie la réactivité des NPFe0 vis-à-vis du TCE, ce qui peut potentiellement affecter l'efficacité du traitement. Ainsi, le premier volet de cette thèse concerne l'étude de la réactivité de NPFe0 brutes ou modifiées par des polyélectrolytes anioniques vis-à-vis du TCE. Cette réactivité a été évaluée au travers des cinétiques de dégradation du TCE et de ses produits de transformation.D'autre part, les eaux souterraines contiennent souvent des espèces dissoutes réductibles pouvant réagir avec Fe0. Ces dernières peuvent affecter la réactivité des NPFe0 vis-à-vis du polluant ciblé et donc l'efficacité du traitement de dépollution. Le deuxième volet de cette thèse porte sur l'effet de deux accepteurs d'électrons (CrVI et NO3-) sur la réactivité des NPFe0 brutes et modifiées. Enfin, le troisième volet de cette thèse concerne l'évaluation de la réactivité des NPFe0 vis-à-vis du TCE dans un cas « réel », afin de valider la technique de dépollution. Une étude pilote et une application in situ ont ainsi été menées sur un site industriel dont l'eau souterraine est contaminée par le TCE (polluant ciblé) avec de fortes teneurs en CrVI et NO3-. / Recent advances in nanotechnology have led to the development of new materials with unique physicochemical properties such as nanoscale zero valent iron particles (nZVI). These nanoparticles proved their efficiency to degrade chlorinated organic compounds such as trichlorethylene (TCE), but their migration in porous media is often limited. To overcome this problem, a solution is to modify their surface by adsorption of organic molecules. However, this coating modifies the reactivity towards TCE, which can potentially affect the treatment efficiency.Thus, the first part of this PhD focuses on the reactivity of nZVI (bare or modified by anionic polyelectrolytes) towards TCE. This reactivity was evaluated through the TCE degradation kinetics rates and its transformation products.In addition, groundwaters often contain reducible species that can react with dissolved Fe0. These last species may affect the reactivity of nZVI towards the target pollutant and therefore the remediation efficiency. The second part of this PhD focuses on the effect of two electron acceptors (CrVI and NO3-) on the reactivity of bare and modified nZVI.Finally, the third part of this PhD presents the assessment of the reactivity of nZVI towards TCE in a "real" case, in order to validate the remediation process. A pilot study and in situ application have been carried out on an industrial site which groundwater is contaminated with TCE (targeted pollutant) with high levels of CrVI and NO3-.

Notre avons étudié le rôle de la profession et des expositions professionnelles aux solvants pétroliers et chlorés dans deux études épidémiologiques sur les facteurs de risque professionnels des cancers du sein chez l'homme et chez la femme. A l’inverse du cancer du sein féminin (50000 nouveaux cas par an en France), le cancer du sein chez l’homme est un cancer rare (<500 cas par an). Il constitue cependant un modèle intéressant pour l’étude des expositions professionnelles qui sont généralement plus élevées chez l’homme que chez la femme. Chez les hommes, nos résultats suggèrent un risque de cancer augmenté chez les mécaniciens de véhicules à moteur et un rôle cancérogène des solvants tels que le benzène et le trichloréthylène. Chez les femmes, malgré des risques élevés mais non significatifs dans plusieurs professions, aucune association avec les expositions aux solvants n’était mise en évidence pour les faibles niveaux d’exposition observés. / We have investigated the role of the occupation and of occupational exposures to petroleum and chlorinated solvents using the data of two epidemiological studies on occupational risk factors of breast cancers in men and in women. Unlike female breast cancer (50,000 new cases per year inFrance), cancer of male breast cancer is a rare disease (<500 cases per year). It should be seen as an interesting model for studying the effects of occupational exposures in the disease as these exposure are generally much higher in men than in women. For men, our results suggest that the risk of cancer is increased among motor vehicle mechanics and support the hypothesis of a carcinogenic effect of solvents such as benzene and trichloroethylene in disease occurrence. In women, several occupations were at increased risk of breast cancer, but results were generally not statistically significant. No association of female breast cancer incidence with exposure to solvents was observed.