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Ecotoxicological Effects of Silver Nanoparticles in Biosolid-Amended Soils to the Earthworm ... PDF

104 Pages·2016·1.22 MB·English
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Ecotoxicological Effects of Silver Nanoparticles in Biosolid-Amended Soils to the Earthworm Eisenia fetida and the Crop Hordeum vulgare Mónica González Linares Department of Natural Resource Sciences McGill University, Montréal November, 2016 A thesis submitted to McGill University In partial fulfillment of the requirements for the degree of Master of Science ©Mónica González Linares, 2016 Suggested short title: Ecotoxicity of Silver Nanoparticles to Earthworms and Barley Abstract The antibacterial properties of silver nanoparticles (AgNP) make them a desirable material for use in the health industry and in many consumer products. The AgNP released from consumer products during regular use and disposal will end up in water treatment plants where they will become a component of the solid wastes that undergo treatment to generate municipal biosolids. When treatment lagoons are emptied, a substantial amount of biosolids is recycled by land application to agricultural fields as fertilizer. This procedure represents a direct pathway for AgNP to enter the soil. There is scant information on the possible effects of AgNP in biosolid-amended soils to the indigenous soil organisms and plants, which highlights the need for nanoecotoxicological testing. The first objective of this thesis was to assess the effects of biosolid-amendments spiked with different concentrations of AgNP on the survival and reproduction of the earthworm Eisenia fetida in soil, as well as the bioaccumulation of Ag in the earthworm tissue after 28 d exposure. Biosolid-amended soils were a natural soil (Delacour series) from an agricultural field and an artificial soil (OECD standard soil) prepared in the laboratory. Lethal effects were measured in earthworms exposed to biosolids in the natural soil spiked with up to 1302.3 mg Ag kg-1 dry soil. Earthworm reproduction was affected in both soil types, where cocoon and juvenile production was reduced at high concentrations of AgNP in biosolid- amended soil. Silver bioaccumulation in earthworm tissue increased monotonically in both soil types as the AgNP concentration in biosolids increased and the maximum amount of bioaccumulated Ag (at the highest concentration of AgNP exposure) was of 62.7 mg Ag kg-1 dry tissue. The second objective of this thesis was to determine the effects of AgNP on barley shoot and root growth in natural and artificial biosolid-amended soils, as well as Ag bioaccumulation in barley tissue. Barley exposed to soils with up to 365.5 mg Ag kg-1 were negatively affected in both their shoot and root development. Silver bioaccumulation in III shoot and root tissue behaved monotonically in both soil types as the Ag concentration biosolid-amended in soil increased. Roots bioaccumulated more Ag (up to 836.9 mg Ag kg-1 dry tissue) than shoots (up to 11.9 mg Ag kg-1 dry tissue). The negative effects of AgNP on earthworms and barley were observed at concentrations that are orders of magnitude greater than the expected concentration of Ag in agricultural fields receiving municipal biosolids. In conclusion, it seems unlikely that biosolids containing AgNP would have adverse effects on soil organisms and plants when agricultural producers follow the current guidelines in applying biosolids as a soil amendment and fertilizer. IV Resumé Les propriétés antibactériennes des nanoparticules d'argent (AgNP) en font un matériau souhaitable pour leur utilisation dans l'industrie de la santé et dans nombreux produits de consommation. Les AgNP libérées des produits de consommation lors de l'utilisation et de l'élimination régulière finiront dans les usines de traitement de l'eau. Elles deviendront un composant des déchets solides qui subiront un traitement pour générer des biosolides municipaux. Lorsque les lagunes de traitement sont vidées, une quantité importante de biosolides est recyclée par épandage sur les champs agricoles comme engrais. Cette procédure représente une voie directe pour les AgNP pour entrer dans le sol. Il y a peu d'informations sur les effets possibles des AgNP contenues dans les sols traités avec biosolides sur les organismes et les plantes indigènes du sol; ceci met en évidence la nécessité de poursuivre des tests nano-écotoxicologiques. Le premier objectif de cette thèse est d'évaluer les effets des traitements de biosolides enrichis avec différentes concentrations des AgNP sur la survie et la reproduction du ver de terre Eisenia fetida dans le sol, ainsi que la bioaccumulation de Ag dans le tissu du ver de terre après 28 jours d'exposition. Deux sols ont été traités avec biosolides: un sol naturel (série Delacour) pris d'un champ agricole et un sol artificiel (sol standard de l'OCDE) préparé dans le laboratoire. Les effets létaux ont été mesurés dans les vers de terre exposés à des biosolides dans le sol naturel enrichi avec jusqu'à 1302.3 mg Ag kg-1 sol sec. La reproduction du ver de terre a été affectée dans les deux types de sol, où la production de cocons et juvéniles a été réduite dans le sol traité avec biosolides à des concentrations élevées de AgNP. La bioaccumulation d’argent dans les tissus du ver de terre a augmenté de façon monotone dans les deux types de sol avec la concentration des AgNP dans les biosolides et le montant maximum de Ag bioaccumulé (à la concentration maximale d'exposition au AgNP) était de 62.7 mg Ag kg-1 tissu sec. V Le deuxième objectif de cette thèse est de déterminer les effets des AgNP sur la croissance de pousse feuilles et de racines d'orge dans les sols naturels et artificiels traités avec des biosolides, ainsi que la bioaccumulation d’Ag dans les tissus de l'orge. La croissance de l’orge dans les sols avec jusqu'à 365.5 mg Ag kg-1 a été affectée négativement à la fois dans leur pousse et le développement des racines. La bioaccumulation d’argent dans le tissu des feuilles et des racines se comporte de façon monotone dans les deux types de sol en fonction de l’augmentation de Ag dans les sols amendés avec des biosolides. Les racines ont accumulé plus d’Ag (jusqu'à 836.9 mg Ag kg-1 tissu sec) que les pousses (jusqu'à 11.9 mg Ag kg-1 tissu sec). Les effets négatifs des AgNP sur les vers de terre et de l'orge ont été observés à des concentrations qui sont des ordres de grandeur supérieure à la concentration attendue d’Ag dans les champs agricoles recevant des biosolides municipaux. En conclusion, il semble peu probable que les biosolides contenant des AgNP auraient des effets néfastes sur les organismes et les plantes du sol lorsque les producteurs agricoles suivent les lignes directrices actuelles dans l'application des biosolides comme amendement et engrais du sol. VI Preface This thesis follows the guidelines set for a manuscript-based thesis by the McGill University Graduate and Postdoctoral Studies Office. It is composed of three chapters, preceded by a general introduction to the subject and followed by overall conclusions from the study. Chapter 1 consist of a review of relevant literature, which establishes the context and the objectives of the study. Chapter 2 describes the effect of silver nanoparticles in biosolid- amended soil to the earthworm Eisenia fetida in two soil types. Chapter 3 investigates the effect of silver nanoparticles in biosolid-amended soil to the plant Hordeum vulgare (barley) in two soil types. The candidate was responsible for designing and conducting all experiments, and for the analysis, calculations and interpretation of data, including statistical analysis. The candidate prepared all tables, figures and wrote the manuscripts. Chapter 2 and 3 are intended to be submitted to international peer-reviewed journals for publication as two scientific articles. Professor Joann K. Whalen and Dr. Geoffrey I. Sunahara are co-authors on the two scientific articles. The co-authors provided guidance in the experimental work and editorial assistance to the candidate during preparation of the manuscripts. VII Acknowledgments I want to firstly thank my supervisor Prof. Joann Whalen for the opportunity of performing these interesting studies, for her support, patience and advice throughout my masters, especially as she knew it was hard at the beginning to learn and adapt to a whole new area of science. I want to also thank Dr. Geoffrey Sunahara for his advice related to my research and the long talks we had more than once; it was always nice talking to and getting advice from such an experienced person. Also, my research would have not been possible without Hélène Lalande; thank you for providing me with knowledge, advice and endless help through my experimental work, thank you for all your patience and kind and positive words; also thank you for aiding me in translating to French the abstract for this thesis. Thanks to the members of Soil Ecology Research Group, for their help and support during this journey. También quiero agradecer a mi papá Jorge González Olvera, gracias, “pa”, por seguirme apoyando en mis estudios, a pesar de que ya está fuera de tus responsabilidades. Muchas gracias por haber apoyado esta meta, que ahora se va cumpliendo, no podría haber llegado hasta este punto sin ti, gracias por creer en mí. Gracias a mi mamá Evangelina Linares Verduzco, por cada palabra de aliento cuando todo parecía que se tornaba gris, porque a pesar de la distancia siempre has estado ahí para seguirme apoyando y empujando hasta cumplir mis metas. También este sueño no hubiera sido el mismo sin mi Panqué y mi Bolillo que viajaron conmigo para seguir mis sueños, y a pesar de que hoy ya no están, los sigo llevando en el corazón. Por último, quiero agradecer a mi esposo Bernardo Stephan Teufel, quien me impulsó a regresar a la universidad y caminó junto a mí durante este trayecto para que pudiera cumplir mi sueño de obtener mi maestría. Gracias a tu sueño de buscar nuevas oportunidades y VIII crecer profesionalmente, pude cumplir el mismo sueño. Gracias, “mol”, por tu apoyo incondicional, consejos, paciencia y ayuda durante estos casi dos años. Gracias por mostrarme que rendirse nunca es una opción en nuestra familia, y que mientras creamos en nosotros mismos, podemos lograr lo que nos propongamos. I want to dedicate this thesis to my mother Evangelina Linares Verduzco, who did not get to see it finished, but who always, through kind words and endless love, deeply supported my goal of obtaining my Masters degree; and who always thought I could do anything I wanted as long as I kept being honest and worked hard enough. IX Table of contents Abstract .................................................................................................................... III Resumé ..................................................................................................................... V Preface ..................................................................................................................... VII Acknowledgments ................................................................................................... VIII Table of Contents ..................................................................................................... X List of Tables ............................................................................................................ XIV List of Figures .......................................................................................................... XV List of Abbreviations ............................................................................................... XVIII Introduction ............................................................................................................. 1 Chapter 1. Literature Review ................................................................................... 3 1.1 Silver nanoparticles: origin and transmission to terrestrial .......................... environments ............................................................................................... 3 1.1.1 Silver nanoparticles ............................................................................... 3 1.1.2 Release of AgNP into the environment ................................................ 4 1.1.3 Biosolids as a point source of AgNP released into agricultural land .... 6 1.1.4 Transformation and potential toxicity of AgNP in biosolid-amended .. soils ....................................................................................................... 8 1.2 Indicator organisms for AgNP toxicity assessments in biosolid-amended ... soils ............................................................................................................. 10 1.2.1 The earthworm Eisenia fetida ............................................................... 10 X

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Ecotoxicity of Silver Nanoparticles to Earthworms and Barley Figure 3.10 Grown barley in biosolid-amended Delacour soil of one of the 5 replicates. exchange spermatozoa from the seminal vesicles to the spermathecae
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