No description available.

Sites contaminated with polycyclic aromatic hydrocarbons can be simultaneously contaminated with trace elements. Co-contaminated soil is considered a complex problem since inorganic and organic contaminants behave differently and thereby often require different remediation strategies. Despite the fact that co-contaminated soils are a common problem, existing research on remediation of contaminated soil mostly focuses on either organic or inorganic contaminants. In the present study, the possibilities of electrokinetic remediation as an alternative to commonly used remediation technologies was investigated. An experiment was setup to evaluate the effects of electrokinetic remediation on both polycyclic aromatic hydrocarbons and trace elements, such as arsenic, cadmium, chromium, copper, lead and zinc, simultaneously. The experiment was performed in 12 litre large plexiglass cells. Two cells with electrokinetic treatment, equipped with iron electrodes, to amend the soil with iron via intentional corrosion of the electrodes, and one control. The cells were filled with contaminated soil and deionized water was pumped through the cells to simulate a groundwater flow. The experiment ran for two months, during which pore water was sampled weekly and simulated groundwater monthly, to monitor changes in contaminant concentrations. Soil samples were taken at the start and at the end of the experiment. Results showed that the concentration of polycyclic aromatic hydrocarbons in the simulated groundwater decreased from 0.39 ± 0.15 μg L-1 to 0.12 ± 0.064 μg L-1 during the experiment. However, at the point of writing, samples of soil at the end of the experiment has not yet been analysed for concentration of polycyclic aromatic hydrocarbons, something that needs to be done to validate previously described results. In terms of the trace elements, the applied method did not increase their mobility, nor did it decrease it. Moreover, the trace elements behaved similarly in the control cell as in the treatment cells. This was observed for all the tested trace elements, indicating that electrokinetic remediation in this particulate case may be a suitable remediation technology for organic, but not that successful for inorganic contaminants. In regard to this, further research is required to establish whether electrokinetic remediation is a promising remediation technology for co- contaminated soil and how it can be optimized to ensure remediation success for both organic and inorganic contaminants.

No description available.

Contaminated land is a widespread, global issue affecting millions of people. Atrazine is a commonly used herbicide which often contaminates groundwater and drinking water supplies and is associated with adverse health outcomes. Biochar is the solid product of pyrolysis and is associated with several environmental benefits. It may be an effective remediation tool when used as a soil amendment. This thesis investigates the mechanisms through which biochar can immobilise atrazine, and the implications of the mechanisms for remediating contaminated land. Nine biochar samples were obtained from the United Kingdom Biochar Research Centre , which were produced from softwood pellets (SWP), wheat straw pellets (WSP), miscanthus straw pellets (MSP), rice husk (RH) and oil seed rape (OSR) each at pyrolysis temperatures of 550°C and 700°C (excluding OSR at 700°C). The sorption mechanisms controlling atrazine sorption to these biochars were determined through various characterisation methods and batch sorption experiments. The sorption tests showed that sorption to each of the standard biochars occurs via multiple simultaneously occurring mechanisms, which are each promoted under certain conditions. Studies investigating sorption kinetics, isotherms and interactions with humic acids showed that for all biochars in this study, pore filling was a significant process through which atrazine is transported to adsorption sites, although poor intraparticle diffusion for softwood and oil seed rape biochars can prevent efficient transport. Wheat straw and rice husk biochars showed effective pore diffusion, resulting in high sorption capacities. Partitioning was associated with poor remediation outcomes and was significant to softwood biochars, although adsorption dominated overall sorption for all other biochars. pH was shown to significantly influence the occurrence of various sorption mechanisms. At low pH values, most biochars showed evidence of electrostatic repulsion between positive atrazine species and the positively charged biochar surface. At intermediate pH values, all biochars showed strong hydrogen bonding between H+ groups on the surface of the biochar and atrazine. A meta-analysis of previous relevant studies provided further evidence for hydrogen bonding of atrazine to biochar and showed that hydrophobic effects likely play little role in adsorption after accounting for the effects of surface area. Varying contributions of π-π EDA interactions, hydrogen bonding involving biochar O- groups, and interactions with ash minerals resulted in different sorption profiles for each biochar at high pH values. In order to further determine the mechanisms controlling sorption at high pH, surface compositions of SWP550, RH700 and OSR550 biochars were modified using hydrofluoric acid. Modification with hydrofluoric acid successfully removed the ash contents of rice husk and oil seed rape biochars and reduced atrazine removal at high pH values. This suggested that the ash fraction increases atrazine removal at high pH through complexation or catalytic hydrolysis. The roles of the various mechanisms are related to remediation outcomes in a novel manner allowing for the improved design of biochar for environmental remediation.

The environmental bioavailability of contaminants, rather than their total concentrations in the soil compartment play a decisive role for the risks associated with contaminated sites. Various soil constituents and abiotic conditions have strong influence on bioavailability, which may vary substantially between different locations. It is therefore necessary to site-specifically use tools that reflect the fractions of contaminants that are available to biota and pose the highest potential environmental risks. Bioassays provide integrated toxic responses which include effects from unknown contaminants or combinatory toxic effects from mixtures of contaminants. Thus, biological effect data greatly contribute to establish more realistic exposure and risk-scenarios at contaminated sites. The work underlying this thesis presents possible techniques for high capacity screening for site-specific hazards at contaminated areas. By combining rapid water extractions and cell-based in vitro designs measures of the toxic potential in soils was obtained. Toxicologically bioavailable fractions of mixed metal pollution, including arsenic, were primarily investigated in this thesis. In two of the studies, environmental availability and toxicological bioavailability of arsenic was explored in CCA-contaminated soils. Application of cell-based in vitro screening techniques was also conducted at a metal contaminated industrial site to obtain spatial distribution of toxicity. Multivariate association techniques were employed in the interpretation of environmental exposure and cytotoxicity data. It was shown that cell-based in vitro systems for both basal cytotoxicity and specific end-points targeting arsenic could assess the toxic potential from extracts obtained by several water-based extraction techniques including Pressurised Liquid Extraction (PLE). The cell-based in vitro systems were found to add important information on the site-specific differences in arsenics genotoxic potential from CCA-contaminated soils. The results highlight the importance of taking speciation and toxicological bioavailability into account in the risk analysis, rather than to base risk estimates on total load of contaminants. The presented screening approach was successfully applied at a metal polluted industrial site where spatial distribution of toxicity was obtained. PLE extraction also provided means for combined toxicological and chemical screening of explosives in soils from live-fire training ranges. Multivariate association techniques highly facilitated the interpretation of complex environmental data. The PLE was found to be a rapid extraction technique that has sufficient environmental relevance to be used in environmental impact analyses. It was also concluded that other cell-based in vitro systems that target specific toxic effects have large potential for being used in screening for a variety of environmental chemicals. Keywords: Environmental availability, Environmental bioavailability, Toxicological bioavailability, mixture toxicity, hazard screening, contaminated soils, heavy metals, arsenic, CCA, explosives, soil extraction, water extracts, cell-based in vitro tests, cytotoxicity, genotoxicity, PLE, MVDA, PCA, PLS. / Föroreningars biotillgänglighet snarare än deras totala koncentration i markmiljön styr den risk som kan förknippas med förorenade områden. Biotillgängligheten är ofta långt från 100% p.g.a. en rad olika bindningsytor och processer i jorden som reducerar biotillgängligheten. Således kan biotillgängligheten variera kraftigt mellan olika förorenade platser och även inom samma plats till följd av de specifika förhållanden som råder på respektive plats. Tillämpning av biologiska indikatorer som ger ett mått på den samlade giftigheten från biotillgängliga föroreningar är därför viktiga verktyg i platsspecifika exponerings- och farobedömningar. Många biologiska tester är ofta laborativt intensiva och dyra och lämpar sig mindre väl i testning av ett stort antal prover vilket är önskvärt om en tillräcklig geografisk täckning ska uppnås över ett förenat område. Testsystem som har kapacitet att hantera många prover till en rimlig kostnad är därför mycket användbart för screening i ett inledande skede av en miljöriskanalys av ett förorenat område. Föreliggande avhandlingsarbete presenterar möjliga lösningar i att kombinera snabb vattenextraktionsmetodik med cellbaserade in vitro system för platsspecifik toxikologisk faroscreening av metallförorenade områden. Metodiken erbjuder hög kapacitet för många jordprover. Tillämpning av metodiken har gjorts mot huvudsakligen metallföroreningar, inklusive arsenik. I två delarbeten studerades två modelljordar från CCA-förorenade fastigheter avseende tillgänglighet och giftighet av framför allt arsenik. Vidare studerades om det med applicerad metodik gick att illustrera geografisk utbredning av toxicitet, mätt i cellbaserade in vitro system, som biotillgängliga föroreningar uppvisar på ett metallförorenat industriområde. Slutligen studerades lämpligheten i att använda PLE för kombinerad kemisk och toxikologisk screening av jordar från militära skjutfält som var förorenade med explosivämnen. Cellbaserade in vitro system för mätning av både generell toxicitet och mer specifika effektmarkörer för arsenik visade sig användbara vid mätning från flera vattenbaserade extraktionsmetoder, inklusive PLE (trycksatt vätskeextraktion). Resultaten visade på PLEs tillämplighet som en snabb extraktionsmetod med bibehållen relevans för miljöanalyser. Applikation av cellbaserade in vitro system på vattenextrakt från förorenad jord gav värdefull information bl.a. om platsspecifik genotoxisk potential där specieringen av arsenik hade avgörande betydelse i en fallstudie med CCA-förorenade jordar. Vattenextraktion av jordprover kombinerat med cellbaserade in vitro system kunde också ge en geografisk bild av den omedelbara faran från biotillgängliga metallföroreningar inom ett industriområde. Vattenextraktion med PLE visade sig även användbart för screening av explosivämnen där extrakten direkt kunde användas för såväl kemisk karakterisering som för toxikologisk analys. Även andra typer av in vitro system än de som användes i detta arbete har stor framtida potential för tillämpning i faroscreening av ett stort antal olika typer av miljöföroreningar.

Evaluation of contaminated sites based on human health and environmental hazards is an essential task for the proper management of the contaminated sites. A large number of contaminated sites have been waiting for remediation all over the World. However, contaminated site remediation is generally a difficult, time consuming and very expensive process. Ranking systems for contaminated sites are useful tools to determine the remedial priority and to manage the available remediation budget in the most efficient way before the costly remedial actions are taken. To be able to have a reliable ranking result, accurate and sufficient amount of data on the nature of contamination and site characteristics are needed, which are usually not available at the early identification phases of contaminated sites, and the available data is mostly limited and vague in nature. If the available data are inaccurate or vague, the corresponding remedial ranking results can be questionable, as well. Most of the current ranking methodologies overlook the vagueness in the parameter values. The main objective of this study is to develop a remedial priority ranking system for contaminated sites by taking vagueness in parameter values into account. Within this context, development of the new Remedial Priority Ranking System, RPRS, aims to define and evaluate the current and possible environmental risks by using sufficiently comprehensive readily available parameters describing the fate and transport of contaminants in the environment and considering vagueness in those parameter values. The consideration of vagueness in parameter values was included in remedial prioritization of contaminated sites by means of fuzzy set theory. A fuzzy expert system was built up for the evaluation of contaminated sites and it was developed in Microsoft Office Excel 2007 platform, with the intention of making the evaluation fast and user friendly. Hypothetical and real case study applications are presented to test ease of use and validity of the results of the developed methodology. Results of case study applications revealed that the developed RPRS can serve as an alternative method for remedial priority ranking of contaminated sites.

[pt] Junto com o desenvolvimento industrial no Brasil vieram os problemas ambientais, como poluição do ar por gases poluentes, poluição de sistemas hídricos por acidentes ambientais, contaminação de solos provocada pela disposição inadequada de resíduos, entre outros. Em virtude disso as áreas contaminadas foram aumentando e, dessa forma, surgiu a necessidade de formulação de programas de preservação e gerenciamento ambiental, bem como estudos de controle e remediação de áreas contaminadas. Esse estudo tem como objetivo analisar o comportamento de um solo argiloso contaminado por cloreto de zinco quando submetido à técnica de encapsulamento. Essa técnica de remediação consiste na inserção de um agente encapsulante que reage com o solo contaminado, solidificando e estabilizando quimicamente o contaminante. Os agentes cimentantes utilizados nesta pesquisa foram a cal hidratada e o cimento Portland (CP V – ARI). Foram estudadas diversas misturas contendo solo argiloso, cloreto de zinco (nos teores de 5 e 10 por cento) e os agentes encapsulantes (cal e cimento, nos teores de 5 e 10 por cento), em diversos tempos de cura. Caracterização geotécnica, ensaios de compactação, de resistência à compressão simples e ensaio de lixiviação (adaptado à um permeâmetro) foram realizados, assim como as análises químicas das amostras e dos lixiviados coletados, para assegurar a eficiência da técnica de encapsulamento. Ensaios de Tomografia e a Microscopia Eletrônica de Varredura também foram realizados para analisar o comportamento e a estrutura das amostras. Os resultados desta pesquisa se mostraram satisfatórios, uma vez que houve uma significativa redução da concentração de contaminante nos lixiviados quando as amostras continham maior quantidade de agente cimentante, prevenindo a poluição do lençol freático. Além disso, também foi possível notar, a partir dos resultados de resistência à compressão simples, que o tempo de cura e as concentrações de contaminante e dos agentes cimentantes influenciam muito na resistência do solo contaminado. Portanto, essas escolhas são determinantes para a eficiência desse tipo de remediação. / [en] Along with the industrial development in Brazil, several environmental problems arose, such as greenhouse gas emissions, pollution of water systems, soil contamination caused by improper disposal of waste, among others. Because of that, contaminated areas soared and consequently the need for the development of remediation studies of contaminated areas emerged. This study aimed to analyze the behavior of a zinc chloride contaminated soil when subjected to the encapsulation technique. This procedure consists of inserting an encapsulating agent to react with the contaminated soil, solidifying and chemically stabilizing the contaminant. The cementing agents used in this research were hydrated lime and Portland cement (CP V – ARI). Different mixtures of clay soil, zinc chloride (in contents of 5 and 10 percent) and those agents (lime and cement, in contents of 5 and 10 percent) were studied in several curing times. Geotechnical characterization tests, compaction tests, unconfined compressive strength tests and leaching tests (adapted from a permeameter) were performed as well as the leachate and samples chemical analysis to ensure the efficiency of the encapsulation technique. Tomography and Scanning Electron Microscopy were also realized to analyse the the behavior and structure of the samples. Research results were satisfactory, since there was a significant reduction of leachate toxicity when the sample had higher contents of encapsulant, preventing the contaminant to pollute water resources. Moreover, it was also possible to realize, from the unconfined compressive strength test, that the curing time and the contaminant and encapsulant agents concentration influences in the contaminated soil strength. Therefore, those choices are crucial for the efficiency of this type of remediation.

Les hydrocarbures aromatiques polycycliques (HAP) sont des polluants organiques largement répandus dans l’environnement. Ils sont très fréquemment détectés dans les sols et sont principalement le produit d’une combustion incomplète de la matière organique. Etant toxiques et cancérigènes, de nombreuses études portant sur leur élimination des sols ont été massivement effectuées au cours des dernières années. Parmi tous les traitements disponibles pour traiter des sols contaminés par les HAP, les approches biologiques sont prometteuses car elles ont un impact limité, voire nul sur l’environnement. Cependant, leur efficacité est étroitement dépendante de nombreux facteurs difficiles à contrôler. L’objectif de cette thèse a été d’obtenir une connaissance plus précise concernant la dépollution biologique de sols contaminés par des HAP, en définissant à travers une série d‘expériences, les conditions les plus appropriées pour leur élimination principalement en termes de caractéristiques physiques et chimiques du sol, de la structure des HAP et leurs concentrations, la densité et la composition microbienne, le pH et l’humidité du sol et la disponibilité des nutriments. Les expériences réalisées dans cette thèse, sont basées sur le compostage de déchets organiques avec des sols contaminés par des HAP. L’ajout de matière organique vise à promouvoir la dégradation biologique simultanée des HAP et des déchets organiques frais en conditions contrôlées. Les résultats attendus de cette approche sont la dégradation des polluants en composés moins nocifs, en raison de la stimulation de l’activité des micro-organismes présents dans le sol ainsi que dans les déchets organiques apportés. Dans le but de comprendre l’influence des facteurs précédemment mentionnés, les expériences ont été menées sur un sol synthétique, artificiellement contaminé, ainsi que sur un sol contaminé provenant d’un site industriel identifié comme pollué par des HAP. Quatre types de déchets organiques frais ont été sélectionnés pour être ajoutés au sol artificiellement contaminé par des HAP. Les résultats ont montré que les boues activées étaient l’amendement organique le plus efficace par rapport au fumier de bufflonnes, aux déchets de cuisine et aux déchets organiques à base de légumes. Un taux d’élimination des HAP totaux supérieur à 60% a été atteint avec les boues activées. En outre, cette série d’expériences a prouvé que les conditions mésophiles étaient plus favorables que les conditions thermophiles, mais également que la teneur en azote, l’importance de la fraction soluble et les teneurs en protéines sont très importantes pour l’élimination des HAP. Sur la base de ces résultats, une série d’expériences a été menée sur un sol historiquement contaminé en apportant des quantités différentes de boues activées (ratio massique sol contaminé : boues activées variant de 1:2, 1:1 , 1:0,5 à 1:0). Contrairement aux résultats obtenus avec le sol artificiel, pour un sol naturellement contaminé, les amendements à base de boues activées n’ont pas stimulé l’élimination de HAP. Les meilleurs résultats ont été obtenu pour le sol non amendé par les boues activées (un rendement d’élimination des HAP totaux de 32% a été atteint en l’absence de boues activées, tandis qu'en présence d’un amendement à base de boues activées les meilleurs résultats ne dépassent pas 14% d’élimination des HAP totaux), cela prouve que la stimulation de micro-organismes pouvant dégrader les HAP est un facteur clé pour le succès du processus de dépollution biologique dans des conditions environnementales favorables / Polycyclic Aromatic Hydrocarbons (PAHs) are organic pollutants widely distributed in the environment and very frequently detected in soils as they are mainly produced from an incomplete combustion of organic matter at high temperature. They are toxic and even carcinogenic, therefore their removal from soils has been massively studied in the past years. Among all treatments suitable for treating soils contaminated by PAHs, biological ones are promising and challenging as they have a low or even no impact on the environment as well as their efficiency is tightly dependent on many factors not easy to control. The objective of this thesis has been to get more accurate knowledge on bioremediation of PAHs contaminated soils, by defining, through a series of experiments, the most suitable conditions for their biological remediation mainly in terms of physical and chemical soil characteristics, PAHs type and concentration, microbial density and composition, pH value, moisture content and availability of nutrients. The bioremediation experiments carried out in this thesis are based on landfarming as well as composting soil treatments and aimed at promoting the simultaneous biodegradation of PAHs and fresh organic wastes under controlled conditions. The expected result of this approach has been the conversion of organic pollutants into less harmful compounds, due to the activity of the microorganisms present in soil as well as in the organic waste added to soil. With the aim of deeply understanding the influence of the aforementioned factors on the bioremediation of PAHs contaminated soil, experiments were conducted on a synthetic soil, artificially contaminated, as well as on a real contaminated soil. In details, four different types of fresh organic waste were selected to be added to PAHs artificially contaminated synthetic soil and the results showed that centrifuged activated sewage sludge (SS) was the most effective organic amendment compared to buffalo manure (BM), food and kitchen waste (FKW) and fruit and vegetable waste (FVW). The removal efficiency of total PAHs reached with SS was actually a little higher than 60%. Furthermore, this set of experiments proved that mesophilic conditions were more performing than thermophilic conditions, as well as the content of nitrogen, soluble fraction and proteins played an important role in the PAHs removal. Based on the previous results, the next set of experiments was conducted on a real contaminated soil amended with different amounts of centrifuged activated SS (e.g. contaminated soil to SS mass ratios were 1:2, 1:1, 1:0.5 and 1:0 as wet weight basis). In contrast to results obtained with synthetic soil, in a real contaminated soil, SS amendment resulted in being not beneficial to PAHs removal. The best results were actually achieved where no SS was added (total PAHs removal efficiency of 32%, whereas with SS the best results showed a value of 14%), proving that the adaptation of microorganisms to PAHs is the key factor for the success of the bioremediation process coupled with setting favorable environmental conditions

No description available.

京都大学 / 0048 / 新制・論文博士 / 博士(地球環境学) / 乙第12827号 / 論地環博第7号 / 新制||地環||24(附属図書館) / 31314 / (主査)教授 勝見 武, 教授 三村 衛, 准教授 乾 徹 / 学位規則第4条第2項該当 / Doctor of Global Environmental Studies / Kyoto University / DFAM