Nas questões ambientais legais, muitas vezes a referência à toxicidade de uma substância é vaga. No entanto, essa informação é essencial para a determinação da extensão do dano. Para fazer a previsão desses valores para o benzeno e hidrocarbonetos policíclicos aromáticos (PAHs), componentes do petróleo, foi feito um estudo QSAR (Quantitative Structure Activity Relationship) por meio de cálculos de mecânica quântica e quimiometria. O objetivo foi construir modelos para prever os valores de coeficiente de partição n-octanol/água, Kow (n-octanol/water partition coefficient) além do estudo das toxicidades dos PAHs. Para este estudo, as geometrias de todas as moléculas foram otimizadas utilizando os métodos semiempíricos AM1, PM3, PM6 e PM7. Desses resultados ainda foram extraídos os descritores teóricos que foram utilizados para descrever os valores de log Kow. Entre todos aqueles calculados, os descritores: energia total, energia eletrônica, área, volume e massa molar foram escolhidos como os parâmetros para o estudo PLS (Partial Least Squares). Além disso, as toxicidades dos PAHs foram calculadas por meio do programa T.E.S.T (Toxicity Estimation Software Tool) disponibilizado gratuitamente pelo EPA (Environmental Protection Agency) e estimados por meio de modelo PLS e gráficos de correlação. Observou-se com esse estudo que todos os métodos apresentaram resultados bastante satisfatórios, uma vez que valores próximos de 1 foram obtidos tanto para o coeficiente de correlação interno, Q2, quanto para o externo, R2. / In the environmental legal issues, often the reference to toxicity of a substance is vague. However, this information is essential for determining the extent of damage. To forecast these values for benzene and polycyclic aromatic hydrocarbons (PAHs), petroleum components, one study QSAR (Quantitative Structure Activity Relationship) was done by calculation of quantum mechanics and chemometrics. The goal was to build models to predict the values of the partition coefficient n-octanol / water, Kow (n-octanol / water partition coefficient) beyond the study of the toxicity of PAHs. For this study, the geometries of all molecules were optimized using the semi-empirical methods AM1, PM3, PM6 and PM7. These theoretical results also descriptors that were used to describe the Log Kow values were extracted. Among those calculated descriptors: total energy, electronic energy, area, volume and molar mass were chosen as the parameters for the study PLS (Partial Least Squares). Furthermore, the toxicities of PAHs were calculated using the TEST (Toxicity Estimation Software Tool) program available free of charge by the EPA (Environmental Protection Agency) and estimated by PLS model and correlation charts. It was observed in this study that all the methods have shown promising results, since values near one were obtained for the standard and cross-validated correlation coefficients R2 and Q2.

Nas questões ambientais legais, muitas vezes a referência à toxicidade de uma substância é vaga. No entanto, essa informação é essencial para a determinação da extensão do dano. Para fazer a previsão desses valores para o benzeno e hidrocarbonetos policíclicos aromáticos (PAHs), componentes do petróleo, foi feito um estudo QSAR (Quantitative Structure Activity Relationship) por meio de cálculos de mecânica quântica e quimiometria. O objetivo foi construir modelos para prever os valores de coeficiente de partição n-octanol/água, Kow (n-octanol/water partition coefficient) além do estudo das toxicidades dos PAHs. Para este estudo, as geometrias de todas as moléculas foram otimizadas utilizando os métodos semiempíricos AM1, PM3, PM6 e PM7. Desses resultados ainda foram extraídos os descritores teóricos que foram utilizados para descrever os valores de log Kow. Entre todos aqueles calculados, os descritores: energia total, energia eletrônica, área, volume e massa molar foram escolhidos como os parâmetros para o estudo PLS (Partial Least Squares). Além disso, as toxicidades dos PAHs foram calculadas por meio do programa T.E.S.T (Toxicity Estimation Software Tool) disponibilizado gratuitamente pelo EPA (Environmental Protection Agency) e estimados por meio de modelo PLS e gráficos de correlação. Observou-se com esse estudo que todos os métodos apresentaram resultados bastante satisfatórios, uma vez que valores próximos de 1 foram obtidos tanto para o coeficiente de correlação interno, Q2, quanto para o externo, R2. / In the environmental legal issues, often the reference to toxicity of a substance is vague. However, this information is essential for determining the extent of damage. To forecast these values for benzene and polycyclic aromatic hydrocarbons (PAHs), petroleum components, one study QSAR (Quantitative Structure Activity Relationship) was done by calculation of quantum mechanics and chemometrics. The goal was to build models to predict the values of the partition coefficient n-octanol / water, Kow (n-octanol / water partition coefficient) beyond the study of the toxicity of PAHs. For this study, the geometries of all molecules were optimized using the semi-empirical methods AM1, PM3, PM6 and PM7. These theoretical results also descriptors that were used to describe the Log Kow values were extracted. Among those calculated descriptors: total energy, electronic energy, area, volume and molar mass were chosen as the parameters for the study PLS (Partial Least Squares). Furthermore, the toxicities of PAHs were calculated using the TEST (Toxicity Estimation Software Tool) program available free of charge by the EPA (Environmental Protection Agency) and estimated by PLS model and correlation charts. It was observed in this study that all the methods have shown promising results, since values near one were obtained for the standard and cross-validated correlation coefficients R2 and Q2.

As more sites containing contaminated sediments are remedied with sediment caps, so grows the interest among site managers and engineers in the benefits afforded by active capping. While traditional sediment caps can effectively manage strongly solid-associated contaminants in many situations, under certain conditions active caps or amendments may be needed to effectively reduce risk to an acceptable level. This research assessed the predicted and observed breakthrough of dissolved organic contaminants in two newly developed geotextiles; one designed to sorb non-aqueous–phase liquids (NAPLs), the other dissolved-phase contaminants. The performance of the geotextiles was then compared to that of another remediation technology that has been deployed in the field for two years. All active materials were then evaluated based on their sorption capacity and their predicted life under field conditions. The sorbent containing geotextiles designed for active capping applications were tested in columns to simulate field conditions, where upwelling groundwater would be contaminated by impacted sediments, thereby transporting contaminants to the water column. The contaminants of interest in these studies were three polycyclic aromatic hydrocarbons (PAHs) of varying hydrophobicity. Breakthrough curves for the materials vii of interest were constructed for the three PAHs and were fit to an advection-dispersion model to predict the mass of contaminants sorbed onto them. This mass was then compared and verified to be similar to values found in literature. The performance of the geotextiles was compared to that of organoclay deployed in Portland, OR, at the McCormick & Baxter Creosoting Company Superfund Site. In 2004, over 22 acres of sediment at the site were remedied with both passive and active caps to mitigate the effects of decades worth of contamination. In certain portions of the site, a 12 inch thick layer of organoclay was employed, while at other portions of the site, conventional sand or a thin reactive core mat with the equivalent of approximately 1 cm of organoclay were employed. The continued effectiveness of these sediment caps was evaluated using a variety of laboratory techniques, including measuring samples’ hexane extractable material, which is a proxy for NAPL contamination, as well as their PAH bulk concentrations. These analyses performed on core samples allowed for the generation of vertical profiles critical to cap evaluation. Despite possessing a significantly greater specific sorption capacity, the geotextiles could not offer the same protection for the extended period of time that the bulk organoclay could. The greater mass of organoclay deployed in bulk at the McCormick & Baxter site allowed a much greater sorption capacity to be placed. It would take over sixty stacked layers of the one of the geotextiles evaluated in these studies to achieve the same capacity for dissolved-phase contaminants as the 1 ft organoclay cap. However, no significant penetration of NAPL into the bulk organoclay has been noted, and thus even the thin layer within a geotextile might have been sufficient at the site, despite its significantly lower overall capacity. The data generated provides information as to the expected capacity of the various sorbent placement approaches and can help guide decisions at other sites. / text

Abstract Polycyclic aromatic hydrocarbons (PAHs) are hydrophobic organic pollutants. Because of their highly hydrophobic property, PAHs easily absorbed by organic matters. They also display highly biological accumulation ability and toxicity. PAHs can interrupt organism¡¦s endocrine systems and some are considered bearing mutagenic or carcinogenic potentialities. Because of industrialigation, the extent of accumulated PAHs in the environment at present is significantly higher than those in the past. Therefore, while it is best to avoid further producing of these compounds if at all feasible; efforts to limit the introduction of these compounds into the environment by treating point pollution sources should always be made. The traditional approach to treat organic pollutants, including PAHs, in wastewater is mainly microbial based degradation. But recently due to its low cost and relatively high efficiency, treatment using aquatic plants combined with microbial degradation became popular. However, there have not much work done in using aquatic plant alone to treat PAHs. To study the sorption of PAHs by aquatic plant can provide information regarding the role of plant and microbial actions, and to enable such bioremediation technology more flexibile and feasible in application. Therefore, the forcus of this research is using plant solely to remove PAHs in a man-made wastewater. In this study, an aquatic plant, Ceratophyllum demersum, was used to sorb phenanthrene (Phe) with a continuous flow device. The competition effect in sorption by another PAHs, pyrene (Pyr), was also studied. In addition, another aquatic plant, Naja gramunea Del., was tested using the same system. In the batch experiment, the sorption kinetic constants of phenanthrene and pyrene for Ceratophyllum demersum are 0.19 and 0.22, respectively. Compared with Ceratophyllum demersum, Naja gramunea Del. has a higher kinetic constant. The sorption equilibrium constants of phenanthrene and pyrene for Ceratophyllum demersum are 1.36 and 19.24, respectively. Compared with Naja gramunea Del., Ceratophyllum demersum has a higher equilibrium constant for phenanthrene, but with a lower equilibrium constant for pyrene. A competition effect was observed by the delayed phenanthrene¡¦s saturation time by using pyrene as the possible background pollutant in the continuous flow system. Naja gramunea Del. was also applied in the same system for treating phenanthrene and pyrene in the same way. In conclusion, these two aquatic plants demonstrated great potentials in applications used for treating wastewaters containing PAHs due to low energy and cost of the device.

Delta Store #3033 in Indianola, MS is suspected of having had a release of petroleum, which may have contaminated the underlying soil and shallow groundwater. Exploratory boring/monitoring wells were drilled on-site noting all soil formations and groundwater encountered. The soil facies encountered show a fining upward sequence, representative of a fluvial depositional environment. Soil contamination is mostly confined to the surficial soil; however, evaluation of lab data, boring logs, and cross sections suggests it is likely the contamination migrated through the surficial confining layer into the underlying strata. The hydraulic conductivity of 1.2 x 10-5 cm/sec, surficial geology consisting mostly of low and some high plasticity clays (CL and CH), a hydraulic gradient of 0.01 to 0.02 ft/ft, and the presence of an overlying concrete pavement suggests that any recent release of hydrocarbons should be confined to the immediate vicinity under the site.

Suwannee River fulvic acid (SRFA) and humic acid (SRHA) were used as dissolved organic matter (DOM) and were applied to probe the effect of DOM. Addition of DOM resulted in decreased first order rate constants for all species selected. The inhibition became more significant as the hydrophobicity of the species increased. The decrease could not be simply attributed to the binding of hydrophobic species to DOM. This can be explained by the physical isolation of iron (II), which binds to hydrophilic sites of DOM and is the hydroxyl radical generation site, from hydrophobic pollutants which bind to hydrophobic sites of DOM. Accordingly, species which could compete agains t this physical isolation by DOM and bring iron (II) closer to target species could increase the degradation rates. This was observed with application of carboxymethyl-ß-cyclodextrin (CMßCD). Effects from concentration, structure of the target species and acidity etc., were studied. The increased degradation rates were observed even in the presence of DOM. Studies on ternary complexes of hydrophobic pollutants, iron (II) and CMßCD were carried with ESMS, UV and Fluorescence experiments and further calix[6]arene derivatives. Along with the fact that CMßCD can increase the solubility of hydrophobic species and remove them from contaminated sites, this indicates a potential application to in-situ degradation systems. Initial two -phase studies were carried out with quartz sand deposited with polycholobiphenyl (PCBs) and polycyclic aromatic hydrocarbons (PAHs). Successful degradations were observed with PCBs but not PAHs. The difference is attributed to the slow equilibrium of sorbed PAHs with dissolved CMßCD and the higher PAH loading used in these experiments. A halide sensor-molecule (1, 8-diphenylureaylnaphthalene), which performs with increasing fluorescence in the presence of fluoride and decreasing fluorescence with all other halides, was synthesized and reported. Studies using NMR and computer modeling with SPARTAN were carried out to compare the sensor-molecule with an analog, 2, 3-diphenylureaylnaphthalene. Both studies indicated that only fluoride can be accommodated in the space between the urea group protons to form a strong interaction. The sensor-molecule could to lead to improved sensors that overcome limitations with current fluorescence-quenching based anion sensors.

The diploma thesis deals with the determination of sources of polycyclic aromatic hydrocarbons (PAH) and the changes in the PAH concentrations during the last 11 years, from 2006 to 2016. The data were sampled at National Atmospheric Observatory in Košetice, a representative station for the Central European Region. Multidimensional statistical methods as Positive Matrix Factorization (PMF), conditional bivariate probability function (CBPF), and Potential Source Contribution Function (PSCF) were used for data analyses. In the first part, the changes in concentrations of the four specific PAH, Benzo(a)pyrene (BaP), Fluoranthene (FLA), the sums of all the PAH (SUMA), and the Toxical Equivalent (TEQ) was studied. The highest concentration of all four specific PAH was detected at the beginning of the studied period. The immission limit for BaP was not exceeded. Statistically significant decreasing trend for BaP, TEQ, and SUMA PAH was identified. Second part of the thesis studied the PAH source apportionment. The study proved that the station was strongly influenced by the local domestic heating on one hand, and long-distance transportation from the west, and specifically from the northwest on the other hand. The influence of long-distance transport has an increasing trend over time, vice-versa for the...

Uma classe de compostos presente no material particulado atmosférico que desperta particular interesse e constitui-se em motivo de preocupação são os chamados hidrocarbonetos policíclicos aromáticos (HPA). Estes caracterizam-se por possuir dois ou mais anéis aromáticos condensados e são formados pela queima de combustíveis orgânicos na presença de quantidade limitada de oxigênio. Além dos próprios HPA, são importantes, sob o ponto de vista ambiental, seus derivados nitrados e oxigenados. Sua identificação e quantificação são passos importantes no processo de se esclarecer os mecanismos que conduzem à formação desses derivados. Neste trabalho, estudou-se reações fotoquímicas de HPA e nitro-HPA adsorvidos sobre o fotocatalisador dióxido de titânio (TiO2) ou sobre sílica (SiO2) através de técnicas de espectroscopia Raman. Foram conduzidos também estudos espectroeletroquímicos dos HPA através de espectroscopia eletrônica e Raman intensificada (efeito SERS) visando a caracterização vibracional dos produtos de processos faradáicos desses compostos sobre eletrodos, para comparação com os produtos de fotodegradação. Os HPA estudados foram: antraceno, 9-nitroantraceno, fenantreno, fluoreno, fluoranteno, pireno e criseno. Para o estudo das reações fotoquímicas foi feita uma pré-adsorção dos diversos HPA e nitro-HPA sobre TiO2 ou SiO2, que foram então irradiados em 254 nm em intervalos de tempo pré-determinados. Verificou-se mudanças nas estruturas das moléculas em função da exposição à luz ultravioleta. Os resultados obtidos revelaram a formação de intermediários oxidados, com grupamentos C=O. A combinação de dados da fotodegradação de HPA com seu estudo via eletroquímica - utilizando técnicas espectroscópicas para a identificação e caracterização de produtos - trouxe correlações importantes para esclarecer as transformações envolvidas nas etapas iniciais da fotodegradação dessas substâncias. A comparação das estruturas dos intermediários de fotodegradação e dos produtos de oxidação eletroquímica de HPA mostra que o início do processo fotocatalítico de HPA envolve uma etapa de oxidação de maneira análoga ao processo eletroquímico. / One class of chemicals that is present in the particulate matter in the atmosphere is of the so-called polycyclic aromatic hydrocarbons (PAH). They are object of special interest and concern due to their mutagenic properties and carcinogenic effects. PAH are characterized by the presence of two or more aromatic rings in their structure, and they are produced by the burning of organic fuels in a limited amount of oxygen. The study of the photochemical behavior of PAHs is relevant for clarifying some aspects of these complex systems. In this work, we perform experiments that include the UV irradiation of PAH, to observe which species are produced in such condition. Such investigations include the use of a photocatalysts, titanium dioxide – TiO2 – and that will allow the comparison between degradation products in the absence and in the presence of catalysts. Spectroscopic techniques were employed to monitorate the intermediates formed in the photoinduced degradation of PAH and their nitro derivates adsorbed or not on the photocatalyst TiO2. To perform the study of the photochemical reactions, the several PAH and nitro PAH were pre-adsorbed on TiO2 or SiO2, and then irradiated in 254 nm, in pre-determined time intervals. Changes in the structure of the molecules were observed after the exposure to the ultraviolet radiation. Results thus obtained revealed the production of oxidized intermediates bearing the C=O group. The joint analysis of the photodegradation data with those produced by electrochemical means - using spectroscopic techniques to the identification and characterization of the products - lead to important correlations that helped to clarify the transformations that take place in the initial steps of the photodegradation of PAH. By comparing the structures of the intermediates formed both in the photodegradation processes and in the electrochemical oxidation of PAH, it was possible to conclude that the first part of the photocatalytical degradation of those PAH include an oxidation step that is analogous to the electrochemical process.

Polycyclic aromatic hydrocarbons (PAH) are a class of common environmental contaminants known to be phototoxic. PAH Photoinduced toxicity is caused by two mechanisms: photomodification and photosensitization. The photomodification process results in modified PAHs, usually via oxygenation, forming new compounds (oxyPAHs), which are often more soluble than their parent PAHs. The process of photosensitization usually leads to the production of singlet oxygen, a reactive oxygen species (ROS), which in turn is extremely damaging to organic molecules. Both of these processes occur at environmentally relevant levels of actinic radiation. Metals are ubiquitous environmental contaminants found extensively in many aquatic systems. Many metals are toxic at very low levels, and exhibit toxicity via ROS production or via direct binding to a ligand in an organism (Biotic Ligand Model). PAHs and metals often occur as co-contaminants in the environment, and there combined effects have only been examined in a few organisms. The goal of this thesis was to examine the toxicity of PAHs, oxyPAHs, metals and their mixtures to Hyalella azteca in 96 h acute toxicity tests. All of the tests were performed under varying spectra of light; photosynthetically active radiation (PAR), PAR + UVA or simulated solar radiation (SSR) (PAR + UVA radiation + UVB radiation). In addition, chemical exposures in the Dark were performed to assess toxicity in the absence of light. The PAHs chosen represent 3 of the most common PAHs anthracene (ANT), phenanthrene (PHE), benzo(a)anthracene (BAA). The 12 oxyPAHs studied were quinolated analogues of the 3 parent compounds as well as anthraquinone derivatives that are hydroxylated at various positions. The toxicity of the parent PAHs increased in the presence of increasing amounts of actinic radiation. The toxicity of the oxyPAHs also increased as PAR, UVA and UVB was added. Furthermore, most PAHs and oxyPAHs were found to be more toxic than the parent PAHs in the absence of actinic radiation. The metals cadmium (Cd), copper (Cu), nickel (Ni) and zinc (Zn) were used in toxicity tests. These metals were selected based on their high prevalence in aquatic environments and the large amount of data in the published work. The order of metal toxicity in the Dark was Cd > Cu > Zn > Ni. The order of metal toxicity for the PAR and PAR/UV-A regime was Cd = Cu > Ni > Zn. The order of metal toxicity for the SSR treatment was Cu > Cd > Ni > Zn. The toxicity of several metal/PAH mixtures was determined using one of the four metals and ANT, ATQ and 1-hATQ. The mixtures generally had additive toxicity under Dark and PAR lighting regimes. Under SSR lighting most mixtures showed a strictly additive toxicity, however synergistic toxicity was observed for the redox active metals (Cu, Ni) mixed with ANT. In the aquatic environment complex mixtures of PAHs and metals occur. The results of this study illustrate the effects that these mixtures may have on benthic invertebrates.

Polycyclic aromatic hydrocarbons (PAH) are a class of common environmental contaminants known to be phototoxic. PAH Photoinduced toxicity is caused by two mechanisms: photomodification and photosensitization. The photomodification process results in modified PAHs, usually via oxygenation, forming new compounds (oxyPAHs), which are often more soluble than their parent PAHs. The process of photosensitization usually leads to the production of singlet oxygen, a reactive oxygen species (ROS), which in turn is extremely damaging to organic molecules. Both of these processes occur at environmentally relevant levels of actinic radiation. Metals are ubiquitous environmental contaminants found extensively in many aquatic systems. Many metals are toxic at very low levels, and exhibit toxicity via ROS production or via direct binding to a ligand in an organism (Biotic Ligand Model). PAHs and metals often occur as co-contaminants in the environment, and there combined effects have only been examined in a few organisms. The goal of this thesis was to examine the toxicity of PAHs, oxyPAHs, metals and their mixtures to Hyalella azteca in 96 h acute toxicity tests. All of the tests were performed under varying spectra of light; photosynthetically active radiation (PAR), PAR + UVA or simulated solar radiation (SSR) (PAR + UVA radiation + UVB radiation). In addition, chemical exposures in the Dark were performed to assess toxicity in the absence of light. The PAHs chosen represent 3 of the most common PAHs anthracene (ANT), phenanthrene (PHE), benzo(a)anthracene (BAA). The 12 oxyPAHs studied were quinolated analogues of the 3 parent compounds as well as anthraquinone derivatives that are hydroxylated at various positions. The toxicity of the parent PAHs increased in the presence of increasing amounts of actinic radiation. The toxicity of the oxyPAHs also increased as PAR, UVA and UVB was added. Furthermore, most PAHs and oxyPAHs were found to be more toxic than the parent PAHs in the absence of actinic radiation. The metals cadmium (Cd), copper (Cu), nickel (Ni) and zinc (Zn) were used in toxicity tests. These metals were selected based on their high prevalence in aquatic environments and the large amount of data in the published work. The order of metal toxicity in the Dark was Cd > Cu > Zn > Ni. The order of metal toxicity for the PAR and PAR/UV-A regime was Cd = Cu > Ni > Zn. The order of metal toxicity for the SSR treatment was Cu > Cd > Ni > Zn. The toxicity of several metal/PAH mixtures was determined using one of the four metals and ANT, ATQ and 1-hATQ. The mixtures generally had additive toxicity under Dark and PAR lighting regimes. Under SSR lighting most mixtures showed a strictly additive toxicity, however synergistic toxicity was observed for the redox active metals (Cu, Ni) mixed with ANT. In the aquatic environment complex mixtures of PAHs and metals occur. The results of this study illustrate the effects that these mixtures may have on benthic invertebrates.