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Due to their effective antibacterial and antifungal properties, silver nanoparticles (AgNPs) have quickly become the most commonly used nanomaterial, with applications in industry, medicine and consumer products. This increased use of AgNPs over the past decade will inevitably result in an elevated release of nanoparticles into the environment, highlighting the importance of assessing the environmental impacts of these nanomaterials on aquatic ecosystems. Although numerous laboratory studies have already reported on the negative effects of AgNPs to freshwater organisms, only a handful of studies have investigated the impacts of environmentally relevant levels of AgNPs on whole communities under natural conditions. This thesis examines the effects of chronic AgNP exposure on natural freshwater littoral microcrustacean, benthic macroinvertebrate and pelagic zooplankton communities. To assess the responses of these communities to AgNPs, I focused on a solely field-based approach, combining a six-week mesocosm study with a three-year whole lake experiment at the IISD ?Experimental Lakes Area (Ontario, Canada). Our mesocosm study tested the effects of AgNP concentration (low, medium and high dose), surface coating (citrate-and polyvinylpyrrolidone [PVP]-coated AgNPs), and type of exposure (chronic and pulsed addition) on benthic macroinvertebrates in fine and stony sediments. Relative abundances of metal-tolerant Chironomidae in fine sediments were highest in high dose PVP-AgNP treatments;however, no negative effects of AgNP exposure were seen on biodiversity metrics or overall community structure throughout the study. I observed similar results within the whole lake study that incorporated a long-term addition of low levels of AgNPs to an experimental lake. Mixed-effects models and multivariate methods revealeda decline in all species of the littoral microcrustacean family Chydoridae in the final year of the study within our experimental lake, suggesting that this taxon may be sensitive to AgNP exposure;however, these effectswere fairly subtle and were not reflected in the overall composition of littoral communities. No other negative effects of AgNPs were observed on the pelagic zooplankton or benthic macroinvertebrate communities. My results demonstrate that environmentally relevant levels of AgNPs have little impact on natural freshwater microcrustacean and benthic macroinvertebrate communities. Instead, biodiversity metrics and community structure are primarily influenced by seasonal dynamics and nutrient concentrations across both lakes. This thesis highlights the importance of incorporating environmental conditions and the natural variability of communities when examining the potential risks posed by the release of AgNPs into the environment, as simplistic laboratory bioassays may not provide an adequate assessment of the long-term impacts of AgNPs on freshwater systems. Keywords: Silver nanoparticles, zooplankton, benthic macroinvertebrates, littoral microcrustaceans, whole lake experiment, IISD ?Experimental Lakes Area.
The use of nanoparticles in medicine, industrial, and other applications has triggered an interest in their potential. This book explores the use of nanoparticles related to their occurrence in the environment, their impact on biota in aquatic systems, application of new methodologies, and changes associated with new global scenarios. The book also covers the bioaccumulation and internalization of nanoparticles as key aspects to assess their uptake and discusses the methodologies for testing ENPs ecotoxicity at different trophic levels.
The potential release of nanoparticles into aquatic environments is raising global concerns. As antimicrobials, silver nanoparticles (AgNPs) are among the most prominent form in use. Despite this, their fate, long-term toxicity, and ecological relevance have yet to be investigated largely under natural settings with seasonality and environmental complexity. To better understand the environmental significance, we released AgNPs into Lake 222 at the Experimental Lakes Area over two years. AgNPs remained suspended in the water column and were detected throughout the lake and in the lower food web. Total Ag concentrations ranged from below 0.07 to 18.9 ?g L-1 in lake water, and were highly dynamic seasonally both in the epilimnion and hypolimnion depending on the physical, chemical and biological conditions of the lake. Approximately 60% of the measured Ag mass in October was present in the sediment in 2014 and 50% in 2015 demonstrating relatively high sedimentation and removal from the water column. During winter months, Ag was largely absent in the water column under the ice. After ice melt and before summer stratification, Ag concentrations increased in the lake suggesting AgNPs may not be tightly bound to the sediment and are able re-enter the water column during spring mixing events. Despite temporal variation, total Ag was highly synchronous across spatial locations for both years, indicating rapid dispersal upon lake entry. When investigating AgNP sizes using spICPMS, size distributions were similar across spatial locations, with the 40-60 nm size class constituting approximately 60% of all particles iii identified. Large aggregates (>100 nm) and dissolved Ag were infrequently detected within the lake. Ag accumulated in the lower food web ranging from 0.27-16.82 ?g Ag mg C-1 in the bacterioplankton and 0.17-6.45 ?g Ag mg C-1 in algae (particulate fraction). Partial least squares models revealed the highest predictors of Ag accumulation were dissolved nutrients including DOC, TDN, TDP in bacterioplankton. Major predictors for particulate Ag included temperature, dissolved oxygen, and sampling date. The diversity of predictors among biological compartments emphasizes the importance of understanding the role of environmental complexity within the lower food web. Despite Ag accumulation we did not detect strong negative effects on the lake food web. An increase in particulate and bacterioplankton chlorophyll-a occurred after addition in contrast to reference lakes, which may indicate a hormetic response to low dose AgNP concentrations. Our findings provide the first whole-lake perspective regarding Ag fate and toxicity, suggesting small scale experiments may overestimate environmental responses. Keywords: Silver nanoparticles, ecotoxicity, whole-lake experiment, lower food web fate.
The use of nanoparticles in medicine, industrial, and other applications has triggered an interest in their potential. This book explores the use of nanoparticles related to their occurrence in the environment, their impact on biota in aquatic systems, application of new methodologies, and changes associated with new global scenarios. The book also covers the bioaccumulation and internalization of nanoparticles as key aspects to assess their uptake and discusses the methodologies for testing ENPs ecotoxicity at different trophic levels.
This Handbook focuses on the recent advancements in Safety, Risk, Ethical Society and Legal Implications (ESLI) as well as its commercialization of nanotechnology, such as manufacturing. Nano is moving out of its relaxation phase of scientific route, and as new products go to market, organizations all over the world, as well as the general public, are discussing the environmental and health issues associated with nanotechnology. Nongovernmental science organizations have long since reacted; however, now the social sciences have begun to study the cultural portent of nanotechnology. Societal concerns and their newly constructed concepts, show nanoscience interconnected with the economy, ecology, health, and governance. This handbook addresses these new challenges and is divided into 7 sections: Nanomaterials and the Environment; Life Cycle Environmental Implications of Nanomanufacturing; Bioavailability and Toxicity of Manufactured Nanoparticles in Terrestrial Environments; Occupational Health Hazards of Nanoparticles; Ethical Issues in Nanotechnology; Commercialization of Nanotechnology; Legalization of Nanotechnology.
This book reviews advances in the toxicity of nanomaterials, with a focus on nanosensors and nanotoxicity testing, biomagnification, biotransformation, nanosafety, genotoxicity, human health and remediation. This is the second volume on Nanotoxicology and Nanoecotoxicology published in the book series Environmental Chemistry for a Sustainable World.
As nanotechnology enters everyday life, engineered nanoparticles (ENP) will find their way into nature, including surface and groundwater. Here, distinguished experts of water chemistry present dedicated methods for the analysis of nanoparticles in the aquatic environment, their distribution and fate. This includes the influence of complex matrices such as wastewater, brown water with natural organic matter (NOM), and high salt concentrations as well as available and future standardized methods. The background of geogenic, natural nanoparticles is considered in a discussion of known environmental effects, including strategies to test for potential effects on human and environmental health.
Toxicology of Nanoparticles and Nanomaterials in Human, Terrestrial and Aquatic Systems An indispensable compendium detailing the toxicology of nanoparticles with a focus on mechanisms, emerging issues, and new approaches Toxicology of Nanoparticles and Nanomaterials in Human, Terrestrial and Aquatic Systems provides authoritative information on the toxicology of ultrafine and nanoparticulate matter that contaminate terrestrial or aquatic environments and present unique challenges in applied public health and toxicological research. Detailed chapters by a panel of world-renowned experts examine the complementary and dynamic interdependence of aquatic, terrestrial, and human systems and the toxicological impacts on exposure to engineered and manufactured nanoparticles and nanomaterials. Organized into four sections, the book opens with a thorough overview of the field, including known challenges and the necessity for current research activity. The second section describes terrestrial and aquatic systems and the ecotoxicological impact of nanomaterials, followed by critical analysis of the many human health effects of nanomaterials. The book concludes with an in-depth discussion of current gaps in knowledge, future directions, new approach methodologies, alternatives to animal models, and the emerging environmental threat from nanoplastics. Presenting case exemplars of the ecotoxicological impact of nanoparticles in aquatic and terrestrial systems, this important resource: Presents in-depth coverage of ecosafety, environmental behavior, fate and transport, interactive effects with other contaminants, and current challenges in soil nano-ecotoxicology Addresses rising concerns regarding air pollution and neurological disorders, and the roles played by the gastrointestinal system, the mucosal microbiome, and the immunotoxicology and vasculotoxicity of metal-based nanoparticles Provides detailed coverage of nanomaterial health effects from both animal and in vitro models, including the gut microbiome, innate immunity, neurological and cardiovascular impacts, mechanisms of action, and hazard characterization Analyzes key topics in ecological nanotoxicology such as environmental micro- and nano-plastic pollution and applied risk assessment Toxicology of Nanoparticles and Nanomaterials in Human, Terrestrial and Aquatic Systems is essential reading for toxicologists, applied biologists, ecotoxicologists, research scientists, medical professionals, regulators, and advanced students in fields such as public health, environmental ecotoxicology and medicine, immunotoxicology, neurotoxicology, cardiovascular and systems biology, hazard identification, and risk assessment.
A Practitioner's Guide to Freshwater Biodiversity Conservation brings together knowledge and experience from conservation practitioners and experts around the world to help readers understand the global challenge of conserving biodiversity in freshwater ecosystems. More importantly, it offers specific strategies and suggestions for managers to use in establishing new conservation initiatives or improving the effectiveness of existing initiatives. The book: offers an understanding of fundamental issues by explaining how ecosystems are structured and how they support biodiversity; provides specific information and approaches for identifying areas most in need of protection; examines promising strategies that can help reduce biodiversity loss; and describes design considerations and methods for measuring success within an adaptive management framework. The book draws on experience and knowledge gained during a five-year project of The Nature Conservancy known as the Freshwater Initiative, which brought together a range of practitioners to create a learning laboratory for testing ideas, approaches, tools, strategies, and methods. For professionals involved with land or water management-including state and federal agency staff, scientists and researchers working with conservation organizations, students and faculty involved with freshwater issues or biodiversity conservation, and policymakers concerned with environmental issues-the book represents an important new source of information, ideas, and approaches.