Download or read book Redox and Oxygen Control on Water Quality and Mercury Cycling in the Profundal Zone of California Reservoirs written by Byran Conway Fuhrmann and published by . This book was released on 2020 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: California reservoirs are vital resources that serve as a source of raw water for drinking water production, as well as providing other beneficial uses such as flood control, recreation, and wildlife habitat. These benefits can be limited by the excessive growth of algae and poor water quality associated with nutrients enrichment and eutrophication. In eutrophic reservoirs, nutrients can be released from profundal sediment when oxygen is depleted in the bottom water. These nutrients can exacerbate eutrophication if mixed into surface waters. Hypolimnetic anoxia is associated with a variety of additional water quality issues including reduced water treatment efficiency and the release of toxins. The first objective of this dissertation was to investigate the economic implications and greenhouse gas emissions associated with hypolimnetic oxygenation, a system designed to prevent anaerobic conditions in bottom waters to improve water quality and treatability. This study performed an economic analysis and a life cycle assessment (LCA) of a hypolimnetic oxygenation system (HOS) installed in Upper San Leandro (USL), a drinking water reservoir in Oakland, California. The assessment compared water treatment and reservoir management operations under two scenarios, past conditions without a HOS and current conditions where a HOS is operated to improve water treatability. The largest economic benefit and reduction in greenhouse gas emissions (GHG) for the HOS scenario relative to previous operations was obtained from the reduction in ozone use for disinfection in the water treatment process. Construction costs had a more substantial impact than the cost of oxygen use in the net present value (NPV) of the HOS over its lifetime. In contrast, the LCA revealed that HOS oxygen use contributed the larger proportion of GHG emissions. Overall, results indicate that the implementation of HOS in USL was profitable and will lead to reduced GHG emissions over the assumed 60-year life of the system. The second objective of this research was to investigate mercury cycling in Hodges Reservoir, a hypereutrophic sulfate-rich reservoir in San Diego, California. Anaerobic conditions at the sediment-water interface are associated with the buildup of methylmercury (MeHg), an organic form of mercury produced by anaerobic bacteria, in profundal sediment and water. MeHg poses a threat to ecosystem and human health due to its ability to bioaccumulate in aquatic food webs. The overarching goal of this work was to gain deeper insight into MeHg biogeochemical cycling during anaerobic conditions in the profundal zone to inform reservoir management about key mechanisms involved in mercury production, with the aim of lowering mercury bioaccumulation and protecting human and wildlife health. The first study in this effort tracked MeHg production, degradation, and release into hypolimnetic water while anaerobic conditions were prevalent at the sediment-water interface. This involved tracking MeHg in the sediment, porewater, and water column, as well as associated parameters of interest such as redox acceptors and organic matter. Sediment-associated MeHg was greatest at the onset of anaerobic conditions, suggesting MeHg production in profundal sediment may be greatest during the oxic-anoxic transition, due to the abundance of redox acceptors to fuel anaerobic respiration. The depletion of bioavailable iron-oxide occurred simultaneously with the liberation of MeHg from the sediment, suggesting iron-oxide dissolution led to the release of organic-matter-associated MeHg to overlay water. The activity of sulfate-reducing bacteria (SRB) in the late spring and early summer was associated with the build-up of MeHg in profundal sediment. The depletion of sulfate in the porewater during mid-summer appears to have led to methanogenesis and high levels of biodemethylation. A second study used microcosm incubations of profundal sediment and bottom water to assess seasonal patterns of MeHg cycling under various chemical treatments. Treatments included addition of air, organic carbon, and microbial inhibitors. Both aeration and sodium molybdate, a SRB inhibitor, generally caused a decrease in MeHg concentration, likely by inhibiting SRB activity. A methanogenic inhibitor resulted in a significant increase in MeHg concentration, indicating a suppressive effect by methanogens on net MeHg production, potentially due to enhanced microbial demethylation. Pyruvate resulted in a significant increase in MeHg concentration in the spring when the sediment-water interface was moderately reduced, but caused a significant decrease in the fall under highly reduced conditions. Acetate resulted in a significant increase in MeHg concentration, likely due to the stimulation of acetogenic SRB. Collective results highlight the complex temporal dynamics of MeHg cycling at the sediment-water interface, which is regulated by organic matter composition, redox acceptor availability, and sediment microbial community structure and activity. MeHg production and release at the sediment-water interface was elevated under moderately reduced conditions, which may be the primary period of MeHg entry into the water column and aquatic food web entry. This indicates that management strategies to repress mercury bioaccumulation should focus on the key window of moderately reducing conditions during the onset of anaerobic conditions. Hypolimnetic oxygenation, if it is designed and operated to maintain an oxygenated sediment-water interface, could be a viable approach to repress the MeHg release observed with iron-oxide dissolution and MeHg production in the surficial sediment by SRB. The study also showed that that the sediment-water interface transitioned to be a net sink for MeHg during highly reduced conditions in the fall, likely due to enhanced demethylation by methanogens. Thus, highly reduced conditions appear to be a sink for MeHg in the profundal zone. This indicates that care must be taken to ensure the sediment-water interface is fully oxygenated to prevent mildly reducing conditions associated with MeHg production and release. Together, the results of this comprehensive research suggest that hypolimnetic oxygenation can be an economically viable and environmentally sound solution to enhancing source water treatability while potentially reducing MeHg bioaccumulation.
Download or read book Effects of Oxygen and Nitrate on Mercury Cylcing in the Profundal Zone of Lakes and Reservoirs written by Ricardi Duvil and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Methylmercury, a neurotoxin, has been identified as a serious public health concern. To date, effective remediation techniques for preventing and remediating methylmercury contamination have remained elusive, mainly due to the lack of knowledge in regard to how methylmercury is generated and degraded in the aquatic environment. This dissertation evaluated methylmercury accumulation in both replicate experimental chambers containing undisturbed sediment-water interface samples from mercury-contaminated lakes in northern California, and a two-year field study evaluating spatial and temporal patterns of nitrate, oxygen and methylmercury during summer stratification in Occoquan Reservoir, Virginia. The primary objective of this research was to access how oxidants, including nitrate, affect the cycling of mercury in the profundal zone of lakes and reservoirs. Results demonstrated that methylmercury accumulation in both experimental chamber water and field sampling was lower under aerobic and anoxic (no oxygen but nitrate present) conditions versus anaerobic conditions. In Guadalupe Reservoir, California, MeHg efflux measured in replicate bench-scale chambers averaged 5.5 ng/m2/d under aerobic conditions and 22 ng/m2/d under anaerobic conditions. In Almaden Lake, California, MeHg efflux was -2.3 ng/m2/d (uptake) under aerobic conditions and 11 ng/m2·d under anaerobic conditions. Like oxygen, nitrate repressed MeHg efflux from sediments from Almaden Lake to
Download or read book Mercury Contamination in Fish from Northern California Lakes and Reservoirs written by California. Department of Water Resources. Northern District and published by . This book was released on 2007 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Water Quality Problems at Selected California Reservoirs written by Kenneth P. Kuhn and published by . This book was released on 1980 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Remediation Strategies for Mercury Contaminated Lakes and Reservoirs Within the State of California written by Emily Chortek and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Mercury is an environmental and public health concern due to its neurodegenerative effects and ubiquitous concentration within the environment. To mitigate these risks and reduce concentrations within the environment, remediation methods are necessary. The purpose of this paper is to investigate and evaluate the efficacy of a number of remediation options for mercury contaminated lakes and reservoirs in the State of California. This paper also identifies a number of challenges associated with the implementation of each method and provides recommendations for environmental managers to use when remediating mercury contaminated lakes. Hypolimnetic oxygenation (HOS) was found to be the least problematic remediation method and nitrate additions were found to be the most problematic. Remediation through dredging is only ideal for severely polluted sediments and can be cost prohibitive for many environmental managers. Phytoremediation is not an ideal method either due to lack of non-invasive mercury accumulating plants. Aqueous capping is a viable method, but only if the lake or reservoir is small in size. HOS is the least problematic remediation method investigated in this paper. HOS controls and prevents mercury from being methylated and entering the food web with the added benefit of increasing oxygen levels and cooling benthic temperatures. In order to decrease mercury deposition and mercury concentrations within California lakes, it is recommended that State and Federal legislation be passed to set mercury emission standards to reduce atmospheric deposition and emissions from coal fired power plants. In conjunction with legislative action, it is also recommended that both old and new coal fired power plants be fitted with advanced pollution control technologies to decrease mercury emissions in the United States. There is also the need to prioritize lakes for remediation efforts across the state due to limited environmental funding. Furthermore, it is also recommended to reduce risk of exposure in humans to eat fish lower on the food chain, or to eradicate animal proteins from their diet entirely.
Download or read book Application of a Model for Mercury Cycling in Reservoirs to Finlay Reach Williston Reservoir BC written by Tetra Tech, Inc and published by . This book was released on 2002 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Rates Constants and Kinetics Formulations in Surface Water Quality Modeling written by Environmental Research Laboratory (Athens, Ga.) and published by . This book was released on 1978 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Water Quality in Dynamic Redox Environments written by Christian William Dewey and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Rising population and changing climate threaten to amplify the risks posed by metal contaminants to our freshwater resources. Altered hydrologic cycles and increased demand for freshwater will shift biogeochemical conditions in soils and sediments, potentially transforming metal contaminants from stationary (solid) phases to mobile forms, which are subject to transport and human consumption. Often, redox processes control partitioning of metal contaminants, whether by changing the redox state of the metal itself, or by transforming the metal host(s). In soils and sediments, these redox processes are commonly driven by hydrologic conditions. My research seeks to understand how redox-associated biogeochemical processes arising from and coupled to hydrologic conditions impact metal contaminant partitioning and mobilization. I employ a combination of experimental, spectroscopic, field and modeling approaches to study the partitioning of U, Pb and Cd to solid and dissolved phases in dynamic redox environments. In my first chapter, I find that the calcium-uranyl-carbonato species kinetically limit U(VI) reduction by Fe(II)(aq), thereby impeding transformation of U from a soluble form to an insoluble form. In my second chapter, I show that the stability of Pb in a range of bonding environments limits dissolved Pb concentrations in contaminated floodplain sediments, despite redox-driven dissolution of Pb hosts. In my third chapter, I reveal that soil redox conditions influence the metal-binding properties of dissolved organic matter, leading to increased complexation of Cd by soft ligands in reduced environments. Finally, in my fourth chapter, I find that the impacts of beaver dams on hyporheic biogeochemical activity dwarfs that of seasonal hydrologic dynamics. Overall, my work both furthers our understanding of the biogeochemical cycles of U, Pb, and Cd and deepens our understanding of how changes in hydrology couple with biogeochemical redox processes to determine water quality.
Download or read book Aquatic Sciences and Fisheries Abstracts written by and published by . This book was released on with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Water Quality Assessments written by Deborah V Chapman and published by CRC Press. This book was released on 1996-08-22 with total page 658 pages. Available in PDF, EPUB and Kindle. Book excerpt: This guidebook, now thoroughly updated and revised in its second edition, gives comprehensive advice on the designing and setting up of monitoring programmes for the purpose of providing valid data for water quality assessments in all types of freshwater bodies. It is clearly and concisely written in order to provide the essential information for all agencies and individuals responsible for the water quality.
Download or read book Water Quality for Ecosystem and Human Health written by Geneviève M. Carr and published by UNEP/Earthprint. This book was released on 2008 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt: This document is intended to provide an overview of the major components of surface and ground water quality and how these relate to ecosystem and human health. Local, regional and global assessments of water quality monitoring data are used to illustrate key features of aquatic environments, and to demonstrate how human activities on the landscape can influence water quality in both positive and negative ways. Clear and concise background knowledge on water quality can serve to support other water assessments.
Download or read book Marine Carbon Biogeochemistry written by Jack J. Middelburg and published by Springer. This book was released on 2019-01-25 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt: This open access book discusses biogeochemical processes relevant to carbon and aims to provide readers, graduate students and researchers, with insight into the functioning of marine ecosystems. A carbon centric approach has been adopted, but other elements are included where relevant or needed. The book focuses on concepts and quantitative understanding of primary production, organic matter mineralization and sediment biogeochemistry. The impact of biogeochemical processes on inorganic carbon dynamics and organic matter transformation are also discussed.
Download or read book Selected Water Resources Abstracts written by and published by . This book was released on 1982 with total page 1060 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Water Quality written by Claude E. Boyd and published by Springer Nature. This book was released on 2019-09-12 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume is of great importance to humans and other living organisms. The study of water quality draws information from a variety of disciplines including chemistry, biology, mathematics, physics, engineering, and resource management. University training in water quality is often limited to specialized courses in engineering, ecology, and fisheries curricula. This book also offers a basic understanding of water quality to professionals who are not formally trained in the subject. The revised third edition updates and expands the discussion, and incorporates additional figures and illustrative problems. Improvements include a new chapter on basic chemistry, a more comprehensive chapter on hydrology, and an updated chapter on regulations and standards. Because it employs only first-year college-level chemistry and very basic physics, the book is well-suited as the foundation for a general introductory course in water quality. It is equally useful as a guide for self-study and an in-depth resource for general readers.
Download or read book Water Quality Monitoring written by Jamie Bartram and published by CRC Press. This book was released on 2020-10-14 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt: Water quality monitoring is an essential tool in the management of water resources and this book comprehensively covers the entire monitoring operation. This important text is the outcome of a collborative programme of activity between UNEP and WHO with inputs from WMO and UNESCO and draws on the international standards of the International Organization of Standardization.
Download or read book Guidelines for Drinking water Quality written by World Health Organization and published by World Health Organization. This book was released on 1993 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume describes the methods used in the surveillance of drinking water quality in the light of the special problems of small-community supplies, particularly in developing countries, and outlines the strategies necessary to ensure that surveillance is effective.
Download or read book Monitored Natural Attenuation of Inorganic Contaminants in Ground Water written by and published by . This book was released on 2007 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: V.3 ... consists of individual chapters that describe 1) the conceptual background for radionuclides, including tritium, radon, strontium, technetium, uranium, iodine, radium, thorium, cesium, plutonium-americium and 2) data requirements to be met during site characterization.
