Bioremediation of PAHs - Limitations and soultions

Introduction 1.1 Occurrence of polycyclic aromatic hydrocarbons (PAH) in the environment Worldwide industrial and agricultural developments have released a large number of natural and synthetic hazardous compounds into the environment due to careless waste disposal, illegal waste dumping and accidental spills. As a result, there are numerous sites in the world that require cleanup of soils and groundwater. Polycyclic aromatic hydrocarbons (PAHs) are one of the major groups of these contaminants (Da Silva et al., 2003). PAHs constitute a diverse class of organic compounds consisting of two or more aromatic rings with various structural configurations (Prabhu and Phale, 2003). Being a derivative of benzene, PAHs are thermodynamically stable. In addition, these chemicals tend to adhere to particle surfaces, such as soils, because of their low water solubility and strong hydrophobicity, and this results in greater persistence under natural conditions. This persistence coupled with their potential carcinogenicity makes PAHs problematic environmental contaminants (Cerniglia, 1992; Sutherland, 1992). PAHs are widely found in high concentrations at many industrial sites, particularly those associated with petroleum, gas production and wood preserving industries (Wilson and Jones, 1993). 1.2 Remediation technologies Conventional techniques used for the remediation of soil polluted with organic contaminants include excavation of the contaminated soil and disposal to a landfill or capping - containment - of the contaminated areas of a site. These methods have some drawbacks. The first method simply moves the contamination elsewhere and may create significant risks in the excavation, handling and transport of hazardous material. Additionally, it is very difficult and increasingly expensive to find new landfill sites for the final disposal of the material. The cap and containment method is only an interim solution since the contamination remains on site, requiring monitoring and maintenance of the isolation barriers long into the future, with all the associated costs and potential liability. A better approach than these traditional methods is to completely destroy the pollutants, if possible, or transform them into harmless substances. Some technologies that have been used are high-temperature incineration and various types of chemical decomposition (for example, base-catalyzed dechlorination, UV oxidation). However, these methods have significant disadvantages, principally their technological complexity, high cost , and the lack of public acceptance. Bioremediation, on the contrast, is a promising option for the complete removal and destruction of contaminants. 1.3 Bioremediation of PAH contaminated soil & groundwater Bioremediation is the use of living organisms, primarily microorganisms, to degrade or detoxify hazardous wastes into harmless substances such as carbon dioxide, water and cell biomass Most PAHs are biodegradable unter natural conditions (Da Silva et al., 2003; Meysami and Baheri, 2003) and bioremediation for cleanup of PAH wastes has been extensively studied at both laboratory and commercial levels- It has been implemented at a number of contaminated sites, including the cleanup of the Exxon Valdez oil spill in Prince William Sound, Alaska in 1989, the Mega Borg spill off the Texas coast in 1990 and the Burgan Oil Field, Kuwait in 1994 (Purwaningsih, 2002). Different strategies for PAH bioremediation, such as in situ , ex situ or on site bioremediation were developed in recent years. In situ bioremediation is a technique that is applied to soil and groundwater at the site without removing the contaminated soil or groundwater, based on the provision of optimum conditions for microbiological contaminant breakdown.. Ex situ bioremediation of PAHs, on the other hand, is a technique applied to soil and groundwater which has been removed from the site via excavation (soil) or pumping (water). Hazardous contaminants are converted in controlled bioreactors into harmless compounds in an efficient manner. 1.4 Bioavailability of PAH in the subsurface Frequently, PAH contamination in the environment is occurs as contaminants that are sorbed onto soilparticles rather than in phase (NAPL, non aqueous phase liquids). It is known that the biodegradation rate of most PAHs sorbed onto soil is far lower than rates measured in solution cultures of microorganisms with pure solid pollutants (Alexander and Scow, 1989; Hamaker, 1972). It is generally believed that only that fraction of PAHs dissolved in the solution can be metabolized by microorganisms in soil. The amount of contaminant that can be readily taken up and degraded by microorganisms is defined as bioavailability (Bosma et al., 1997; Maier, 2000). Two phenomena have been suggested to cause the low bioavailability of PAHs in soil (Danielsson, 2000). The first one is strong adsorption of the contaminants to the soil constituents which then leads to very slow release rates of contaminants to the aqueous phase. Sorption is often well correlated with soil organic matter content (Means, 1980) and significantly reduces biodegradation (Manilal and Alexander, 1991). The second phenomenon is slow mass transfer of pollutants, such as pore diffusion in the soil aggregates or diffusion in the organic matter in the soil. The complex set of these physical, chemical and biological processes is schematically illustrated in Figure 1. As shown in Figure 1, biodegradation processes are taking place in the soil solution while diffusion processes occur in the narrow pores in and between soil aggregates (Danielsson, 2000). Seemingly contradictory studies can be found in the literature that indicate the rate and final extent of metabolism may be either lower or higher for sorbed PAHs by soil than those for pure PAHs (Van Loosdrecht et al., 1990). These contrasting results demonstrate that the bioavailability of organic contaminants sorbed onto soil is far from being well understood. Besides bioavailability, there are several other factors influencing the rate and extent of biodegradation of PAHs in soil including microbial population characteristics, physical and chemical properties of PAHs and environmental factors (temperature, moisture, pH, degree of contamination). Figure 1: Schematic diagram showing possible rate-limiting processes during bioremediation of hydrophobic organic contaminants in a contaminated soil-water system (not to scale) (Danielsson, 2000). 1.5 Increasing the bioavailability of PAH in soil Attempts to improve the biodegradation of PAHs in soil by increasing their bioavailability include the use of surfactants , solvents or solubility enhancers.. However, introduction of synthetic surfactant may result in the addition of one more pollutant. (Wang and Brusseau, 1993).A study conducted by Mulder et al. showed that the introduction of hydropropyl-ß-cyclodextrin (HPCD), a well-known PAH solubility enhancer, significantly increased the solubilization of PAHs although it did not improve the biodegradation rate of PAHs (Mulder et al., 1998), indicating that further research is required in order to develop a feasible and efficient remediation method. Enhancing the extent of PAHs mass transfer from the soil phase to the liquid might prove an efficient and environmentally low-risk alternative way of addressing the problem of slow PAH biodegradation in soil.

Women writing Ireland, 1798 – 1921: il popular novel tra identità nazionale e immaginario religioso nelle autrici cattoliche e protestanti.

La presente tesi si concentra sul romanzo popolare irlandese scritto da donne, nel periodo compreso tra il 1798 e il 1921. Quattro sono le autrici prese in considerazione: Charlotte Elizabeth Tonna, Sydney Owenson (meglio conosciuta come Lady Morgan), Edith Somerville e Katharine Tynan, le cui vite e opere coprono un periodo storico fondamentale per l’uscita dell’Irlanda dal dominio coloniale britannico e la formazione della nazione irlandese nel sud del paese. L’interesse principale è quello di analizzare il modo in cui nei loro testi prende forma la nazione, e in particolare attraverso quali immagini e riferimenti religiosi. Il senso è quello, dunque, di rileggere tali testi prestando maggiore attenzione alla religione, uno dei principali collanti tra autrici e pubblico: all’epoca in cui l’Irlanda stava acquisendo i confini che oggi ancora mantiene, esisteva un terreno d’incontro tra discorso politico e letterario, quello della nazione, e tale terreno veniva attraversato anche dal messaggio religioso. Il fine ultimo è quello di dimostrare che la letteratura popolare non è “seconda” ad altre quanto a valori che è in grado di trasmettere e a messaggi che è in grado di veicolare: trascurarla significa non capire i meccanismi attraverso i quali una società si sviluppa e si modifica.

"Sleeping Princess" (1921) e "Baiser de la Fée" (1928): lesina e punteruolo di Stravinskij sulle musiche di Čajkovskij.

Igor Stravinskij (1882-1971) utilizzò di sovente fonti preesistenti come parte integrante del proprio artigianato compositivo. In questa tesi dottorale ho studiato il processo creativo di Stravinskij negli anni Venti sulle musiche di Pëtr Il'ič Čajkovskij (1840-1893). Nella prima parte della dissertazione ho indagato la Sleeping Princess (1921) e il successivo Mariage d’Aurore (1922-1929), entrambi allestiti dai Ballets russes di Sergej Djagilev (1872-1929). Dopo aver localizzato e contestualizzato le fonti manoscritte e i materiali d’uso, ho ricostruito le ri-orchestrazioni effettuate da Stravinskij della Danse russe (Coda del Pas de deux n. 28) e del Presto del Finale (n. 30), che erano a tutt’oggi inedite. La ricerca sulla Sleeping Princess si è rivelata fondamentale per la conseguente analisi del Baiser de la Fée (1928, Ballets de Mme Ida Rubinstein), balletto basato su pezzi pianistici e romanze per voce e pianoforte di Čajkovskij. Grazie allo studio dello Skizzenbuch VIII, della partitura pianistica manoscritta e di tutte le fonti rinvenute, ho gettato ulteriore luce sul processo compositivo di Stravinskij sulle fonti čajkovskiane. Ho rinvenuto nuove appropriazioni che finora non erano note.

La traduzione per l'infanzia in Italia: le traduzioni de "The Secret Garden" (1921-2013)

Questa tesi si concentra sulle traduzioni italiane del classico in lingua inglese The Secret Garden (1911) di Frances Hodgson Burnett, con particolare attenzione all'uso della lingua e all'evoluzione della prassi traduttiva. Nella prima parte di questa tesi ho approfondito temi di natura teorica, quali la sfuggente e complessa definizione di letteratura per l'infanzia, la sua duplice appartenenza al sistema letterario e a quello pedagogico, e le peculiarità della sua traduzione. Inoltre ho presentato un excursus sulla storia di questo genere letterario, con particolare attenzione alla scena italiana e all'opera di propagazione della lingua portata avanti dai libri per ragazzi. Tali basi teoriche sono state necessarie allo scopo di inquadrare il romanzo in una cornice definita e utile in riferimento all'analisi e alla comparazione delle sue traduzioni. Il corpus delle traduzioni scelte consiste nei lavori di: Maria Ettlinger Fano (1921), Angela Restelli Fondelli (1956), F. Ghidoni (1973), Giorgio van Straten (1992) e Beatrice Masini (2013). Di ciascuna opera ho dato una descrizione generale, per poi concentrarmi sugli snodi traduttivi principali: da un lato i problemi di mediazione culturale come l'onomastica, i cibi, le lingue non standard nel testo originale, la religione e così via; dall'altro le soluzioni linguistiche adottate. Al fine di presentare e comparare questi parametri, ho portato a supporto i passaggi delle diverse traduzioni significativi in tal senso. Ho concluso con alcune considerazioni finali sull'evoluzione delle traduzioni italiane di The Secret Garden, viste attraverso l'ottica del rapporto fra adulti (traduttore, editore, educatori, genitori...) e lettore bambino.

The Accident and the Beautiful: On Alan Shapiro's "The Accident"

http://muse.jhu.edu/journals/literature_and_medicine/v030/30.1.schweizer.pdf

Exhibit: "Michigan-I-O": Alan Lomax and the 1938 Library of Congress Folk-Song Expedition"

In 1938, a young folk music collector named Alan Lomax—destined to become one of the legendary folklorists of the 20th century recorded Michigan’s richly varied folk music traditions for the Archive of American Folk-Song at the Library of Congress. Michigan in the 1930s was experiencing a golden age of folksong collecting, as local folklorists mined the trove of ballads remembered by aging lumbermen and Great Lakes schoonermen. In addition to the ballads of these north woods singers, Lomax recorded a vibrant mix of ethnic music from Detroit to the western Upper Peninsula. The multimedia performance event Folksongs from Michigan-i-o combines live performance with historic images, color movie footage, and recorded sound from the Great Depression. Some of these materials haven’t been heard or seen by the general public for more than seven decades. The traveling exhibition Michigan Folksong Legacy: Grand Discoveries from the Great Depression brings Alan Lomax’s 1938 field trip to life through words, song lyrics, photographs, and sound recordings. Ten interpretive banners explore themes and each panel contains a QR code that links to related sound recordings from the Alan Lomax Collection at the American Folklife Center, Library of Congress.

Exhibit: "Michigan-I-O": Alan Lomax and the 1938 Library of Congress Folk-Song Expedition"

In 1938, a young folk music collector named Alan Lomax—destined to become one of the legendary folklorists of the 20th century recorded Michigan’s richly varied folk music traditions for the Archive of American Folk-Song at the Library of Congress. Michigan in the 1930s was experiencing a golden age of folksong collecting, as local folklorists mined the trove of ballads remembered by aging lumbermen and Great Lakes schoonermen. In addition to the ballads of these north woods singers, Lomax recorded a vibrant mix of ethnic music from Detroit to the western Upper Peninsula. The multimedia performance event Folksongs from Michigan-i-o combines live performance with historic images, color movie footage, and recorded sound from the Great Depression. Some of these materials haven’t been heard or seen by the general public for more than seven decades. The traveling exhibition Michigan Folksong Legacy: Grand Discoveries from the Great Depression brings Alan Lomax’s 1938 field trip to life through words, song lyrics, photographs, and sound recordings. Ten interpretive banners explore themes and each panel contains a QR code that links to related sound recordings from the Alan Lomax Collection at the American Folklife Center, Library of Congress.

Exhibit: "Michigan-I-O": Alan Lomax and the 1938 Library of Congress Folk-Song Expedition

In 1938, a young folk music collector named Alan Lomax—destined to become one of the legendary folklorists of the 20th century recorded Michigan’s richly varied folk music traditions for the Archive of American Folk-Song at the Library of Congress. Michigan in the 1930s was experiencing a golden age of folksong collecting, as local folklorists mined the trove of ballads remembered by aging lumbermen and Great Lakes schoonermen. In addition to the ballads of these north woods singers, Lomax recorded a vibrant mix of ethnic music from Detroit to the western Upper Peninsula. The multimedia performance event Folksongs from Michigan-i-o combines live performance with historic images, color movie footage, and recorded sound from the Great Depression. Some of these materials haven’t been heard or seen by the general public for more than seven decades. The traveling exhibition Michigan Folksong Legacy: Grand Discoveries from the Great Depression brings Alan Lomax’s 1938 field trip to life through words, song lyrics, photographs, and sound recordings. Ten interpretive banners explore themes and each panel contains a QR code that links to related sound recordings from the Alan Lomax Collection at the American Folklife Center, Library of Congress.

The Bison: 1983

This digital object was funded in part through a grant from the Andrew W. Mellon Foundation. The digitalization of this object was part of a collaborative effort with the Washington Research Library Consortium and George Washington University.