Download or read book Impacts of Sea Level Rise on Arsenic Mobility and Cycling in Contaminated Coastal Soils written by Joshua J. LeMonte and published by . This book was released on 2016 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: The impacts of sea level rise (SLR) on biogeochemical processes in contaminated soils and sediments along the world’s coastlines remains poorly understood. Elevated levels of the carcinogen arsenic (As), from both geogenic and anthropogenic sources, are found along many coasts, most notably in south and southeast Asia, but also in the US, particularly along the Mid-Atlantic coast. In this work, a combination of laboratory and field techniques were used to ascertain the potential impacts of impending SLR on As mobility and cycling, and the current state of As mobility in a contaminated coastal zone of Delaware, USA. Advanced biogeochemical microcosm reactors were used to simulate inundation with natural sea and river waters on two historically As-contaminated Delaware coastal soils – a wetland soil and ditch sediment – across a wide range of redox potentials while monitoring chemical variables that are known to impact As mobility. Direct As speciation of the soils after reaction at different Eh values was obtained by bulk X-ray absorption near-edge structure (XANES) spectroscopy, X-ray fluorescence (XRF) imaging, and XANES spectroscopy. Reducing conditions led to As release and partial reduction of solid-phase As for both inundation scenarios and both soils. Sulfur speciation was also determined via XANES spectroscopy and showed evidence of sulfate reduction. Prolonged reducing conditions induced by SLR will drive the release of As from historically contaminated soils, but As release may be tempered when inundated by seawater as compared to river water for some soils (e.g. ditch sediment), possibly due to reduced microbial growth in high salinity conditions or preferential sulfate reduction limiting reductive dissolution of As-bearing Fe oxides. However, other soils (e.g. wetland) may see ionic exchange driving pH shifts as a prominent factor driving As release in addition to Eh levels. To assess the contaminant mobility at one of these former industrial sites along the Christina River, we conducted quantitative comparisons of hydrologic and biogeochemical dynamics across time scales ranging from hours to months, and throughout seasonal environmental variations. The use of synchrotron-based X-ray absorption spectroscopy as a geoforensic tool suggests that As from a neighboring Superfund site is likely contributing to recent accumulation of As at the site studied. Data were collected from pressure transducers in wells, multi-level redox sensors, and porewater samplers. Results indicate that groundwater surface interaction induced a tidally controlled redox gradient. In the tidally impacted variably saturated zone, redox potential varied between oxidizing and reducing conditions depending on the water table elevation. This strong correlation indicates that a rising water table may increase contaminant mobility. Porewater samples also confirm increasing arsenic (As) concentration during the rising tide.

Download or read book Managing Arsenic in the Environment written by Ravi Naidu and published by CSIRO PUBLISHING. This book was released on 2006-02-07 with total page 656 pages. Available in PDF, EPUB and Kindle. Book excerpt: Arsenic is one of the most toxic and carcinogenic elements in the environment. This book brings together the current knowledge on arsenic contamination worldwide, reviewing the field, highlighting common themes and pointing to key areas needing future research. Contributions discuss methods for accurate identification and quantification of individual arsenic species in a range of environmental and biological matrices and give an overview of the environmental chemistry of arsenic. Next, chapters deal with the dynamics of arsenic in groundwater and aspects of arsenic in soils and plants, including plant uptake studies, effects on crop quality and yield, and the corresponding food chain and human health issues associated with these exposure pathways. These concerns are coupled with the challenge to develop efficient, cost effective risk management and remediation strategies: recent technological advances are described and assessed, including the use of adsorbants, photo-oxidation, bioremediation and electrokinetic remediation. The book concludes with eleven detailed regional perspectives of the extent and severity of arsenic contamination from around the world. It will be invaluable for arsenic researchers as well as environmental scientists and environmental chemists, toxicologists, medical scientists, and statutory authorities seeking an in-depth view of the issues surrounding this toxin.

Download or read book Arsenic in Soil and Groundwater Environment written by Prosun Bhattacharya and published by Elsevier. This book was released on 2007-06-29 with total page 685 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume presents the recent developments in the field of arsenic in soil and groundwater. Arranged into nine sections, the text emphasizes the global occurrences of arsenic in the environment, particularly on its source, pathways, behavior, and effects it has on soils, plants, water, animals, and humans. It also covers the diverse issues of arsenic in the mining environment, arsenic emanating from hydrothermal springs, and the geochemical modeling of arsenic adsorption to oxide surfaces. Finally, the text includes different cost effective removal mechanisms of arsenic from drinking water using natural red earth, solar oxidation, and arsenic oxidation by ferrrate.Written in simple English, and few technical terms, the book is designed to create interest within the countries with occurrences of arsenic in drinking water with ·an update the current status of knowledge on the dynamics of natural arsenic from the aquifers through groundwater to food chain and efficient techniques for arsenic removal.·serve as a standard text book for graduate, postgraduate students and researchers in the field of Environmental Sciences and Hydrogeochemistry as well as researchers, environmental scientists and chemists, toxicologists, medical scientists and even for general public seeking an in-depth view of arsenic which had been classed as a carcinogen. ·bring awareness, among administrators, policy makers and company executives, on the problem and to improve the international cooperation

Download or read book The Occurrence and Mobility of Arsenic in Soils and Sediments written by Aimee Hegan and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Elevated levels of arsenic (As) in soils and water around the world are both a significant human health and environmental hazard. With increasing global water demands, there is a requirement to further the understanding of the biogeochemical cycling of As from soils and sediments. This thesis focussed on exploring the environmental controls on the occurrence and subsequent mobility of As in a range of natural environments. Arsenic was found to undergo mobilisation from both river sediments and upland peats under changing environmental conditions. The transport of As was found to be correlated with both iron (Fe) and organic carbon (OC), however temporal changes in both sediment/soil composition and movement of water through catchments have a important role in controlling the ultimate transport of As within the environment. A range of investigative methods were employed to study the occurrence and mobility of As within the river sediments of the Allier and Loire Rivers (France), including sequential extraction procedures and batch incubation studies. Arsenic was associated with the reducible phases of sediments, indicating the major role of Fe(oxy)hydroxides in the storage of As in river sediments. In addition to the presence of labile As, the rapid release of As was dependent on the initial sediment composition. Temporal changes in sediment composition may therefore play an important role in controlling the movement of As within fluvial systems. The combination of lead (Pb) and strontium (Sr) isotopic analysis with sequential extraction studies of sediments from the Loire and Allier Rivers was able to determine the relative dominance of granites and basalts within the sediments. This approach provided a first order study on which to better understand the mineral origins of the sediments. The analysis of multiple Pb isotopes was able to eliminate possible anthropogenic contribution to contamination within the sediments, confirming the importance of geogenic cycling of As within the rivers. Information on the origin of mineral formation was obtained through 87Sr/86Sr isotopic analysis, with the formation of Fe-minerals not occurring uniformly along the course of the rivers. While the Sr within the sediment phase targeting well-crystallised Fe(oxy)hydroxides was in equilibrium with the sampled river water, the formation of amorphous Fe minerals was likely occurring in waters upstream of the study sites, within the Massif Central. Total concentration profiles peat from two subcatchments within the Peak District (United Kingdom) provided evidence for both the retention and post depositional movement (PDM) of As within the solid phase, dependent on local conditions. For the first time, the partitioning of As was determined within ombrotrophic peat, and found to be in contrast to Pb, with oxidisible As (likely associated with organic matter) dominating, while Pb was found predominantly within the reducible sediment phase. High temporal resolution monitoring of the organic-rich streamwater draining the peat showed the transport of As was variable, with As found largely in the soluble form despite extensive peat erosion. The evidence for PDM, and the subsequent soluble transport of As demonstrated the importance of biogeochemical processes in releasing As from the solid phase. Once mobilised, both the ratio of Fe:OC and the form of Fe were found to be factors controlling transport of As, with the flushing of stored porewaters an important contribution to As transport from the peat. Despite OC-rich waters, the occurrence of high concentrations of Fe may dominate control of As within the aqueous phase. At relatively high (>0.2) Fe:OC ratios, the particle size distribution of As was closely correlated with that of >1um Fe, although the presence of dissolved and colloidal As was found even within these waters. Given the temporal variability of As transport within the streams, knowledge of the mixing order and ratio between Fe, OC, and As within natural waters may be required for prediction of the mobility and ultimate fate of As.

Download or read book Biogeochemistry of Wetlands written by K. Ramesh Reddy and published by CRC Press. This book was released on 2022-09-10 with total page 926 pages. Available in PDF, EPUB and Kindle. Book excerpt: The globally important nature of wetland ecosystems has led to their increased protection and restoration as well as their use in engineered systems. Underpinning the beneficial functions of wetlands are a unique suite of physical, chemical, and biological processes that regulate elemental cycling in soils and the water column. This book provides an in-depth coverage of these wetland biogeochemical processes related to the cycling of macroelements including carbon, nitrogen, phosphorus, and sulfur, secondary and trace elements, and toxic organic compounds. In this synthesis, the authors combine more than 100 years of experience studying wetlands and biogeochemistry to look inside the black box of elemental transformations in wetland ecosystems. This new edition is updated throughout to include more topics and provide an integrated view of the coupled nature of biogeochemical cycles in wetland systems. The influence of the elemental cycles is discussed at a range of scales in the context of environmental change including climate, sea level rise, and water quality. Frequent examples of key methods and major case studies are also included to help the reader extend the basic theories for application in their own system. Some of the major topics discussed are: Flooded soil and sediment characteristics Aerobic-anaerobic interfaces Redox chemistry in flooded soil and sediment systems Anaerobic microbial metabolism Plant adaptations to reducing conditions Regulators of organic matter decomposition and accretion Major nutrient sources and sinks Greenhouse gas production and emission Elemental flux processes Remediation of contaminated soils and sediments Coupled C-N-P-S processes Consequences of environmental change in wetlands# The book provides the foundation for a basic understanding of key biogeochemical processes and its applications to solve real world problems. It is detailed, but also assists the reader with box inserts, artfully designed diagrams, and summary tables all supported by numerous current references. This book is an excellent resource for senior undergraduates and graduate students studying ecosystem biogeochemistry with a focus in wetlands and aquatic systems.

Download or read book Arsenic Toxicity Challenges and Solutions written by Nitish Kumar and published by Springer Nature. This book was released on 2021-02-15 with total page 413 pages. Available in PDF, EPUB and Kindle. Book excerpt: Arsenic (As) is a widely distributed element in the environment having no known useful physiological function in plants or animals. Historically, this metalloid has been known to be used widely as a poison. Effects of arsenic have come to light in the past few decades due to its increasing contamination in several parts of world, with the worst situation being in Bangladesh and West Bengal in India. This edited volume brings together diverse group of environmental science, sustainability and health researchers to address the challenges posed by global mass poisoning caused by arsenic water contamination. The book covers sources of arsenic contamination, and its impact on human health and on prospective remediation both by bioremediation and phytoremediation. Applications of advance techniques such as genetic engineering and nanotechnology are also discussed to resolve the issue of arsenic contamination in ground water and river basins. The book sheds light on this global environmental issue, and proposes solutions to remove contamination through a multi-disciplinary lens and case studies from Bangladesh and India. The book may serve as a reference to environment and sustainability researchers, students and policy makers. It delivers an outline to graduate, undergraduate students and researchers, as well as academicians who are working on arsenic toxicity with respect to remediation and health issues.

Download or read book Environmental Soil Chemistry written by Donald L. Sparks and published by Elsevier. This book was released on 2022-12-23 with total page 465 pages. Available in PDF, EPUB and Kindle. Book excerpt: Environmental Soil Chemistry, Third Edition provides an up-to-date overview of the interdisciplinary field of environmental soil chemistry. This classic text covers the fundamental principles of soil chemistry, including the inorganic and organic components of soil, soil porewater chemistry, interfacial chemical reactions between solids and dissolved ions/molecules, ion exchange, and the kinetics of the soil chemical process, such as sorption and redox. Soil acidity and salinity are also discussed. This fully updated third edition places particular emphasis on environmental reactions between clay minerals, metal oxides, and soil organic matter with heavy metals, pesticides, and industrial contaminants. This text provides the latest technological advances representing the cutting edge of the science. Completely updated throughout with new content and updated full color figures, the third edition contains expanded information on soil minerals and an increased emphasis on the coupling between chemical and biological reactions, mechanisms, and processes. This third edition provides upper-level undergraduate and graduate students in soil science with sound contemporary training in the basics of soil chemistry and applications to real-world environmental concerns. The book offers a competitive advantage for those students looking to incorporate novel, advanced tools into their research. - Includes problem sets in each chapter for enhanced learning and comprehension - Emphasizes soil organic carbon reactions with clay minerals and metal oxides, including examples from advanced spectromicroscopic techniques - Features revised content highlighting the role of soils in environmental and ecosystem services - Presents new material on advances in surface complexation modeling - Delivers concise summaries of research using state-of-the art techniques - Highlights advances in understanding reactions at mineral-water interfaces, including adsorption, dissolution, and surface precipitation - Offers a new online course supplement for instructors

Download or read book Handbook of Arsenic Toxicology written by Swaran Jeet Singh Flora and published by Academic Press. This book was released on 2014-12-26 with total page 752 pages. Available in PDF, EPUB and Kindle. Book excerpt: Throughout history, arsenic has been used as an effective and lethal poison. Today, arsenic continues to present a real threat to human health all over the world, as it contaminates groundwater and food supplies. Handbook of Arsenic Toxicology presents the latest findings on arsenic, its chemistry, its sources and its acute and chronic effects on the environment and human health. The book takes readings systematically through the target organs, before detailing current preventative and counter measures. This reference enables readers to effectively assess the risks related to arsenic, and provide a comprehensive look at arsenic exposure, toxicity and toxicity prevention. - Brings together current findings on the effects of arsenic on the environment and human health - Includes state-of-the-art techniques in arsenic toxicokinetics, speciation and molecular mechanisms - Provides all the information needed for effective risk assessment, prevention and countermeasure

Download or read book Arsenic Mobility in Suboxic Environments written by and published by . This book was released on 2009 with total page 484 pages. Available in PDF, EPUB and Kindle. Book excerpt: The mechanisms controlling arsenic mobility, including competition with oxyanion ortho-phosphate, in the subsurface and in laboratory controlled experiments were investigated. Additionally, the solubility and meta-stability of GR as a sorbing surface for arsenic in sub-oxic environments was examined. A systems approach was employed to: 1) investigate a model system constrained by thermodynamic constants and a well defined field site, 2) examine a synthetic system to elucidated the effects of co-precipitating oxyanions of arsenic and phosphate with GR, a scenario expected as an environment transitions from oxic to suboxic conditions, and 3) to study the abiotic conditions where GR formation is favorable in suboxic conditions. A systems approach, defined here as the method of investigating a problem by looking at individual but inter-dependent components in the broader context of a larger interdisciplinary environment, was employed to investigate GR in natural and laboratory controlled settings. This research has investigated the mineralogical response, and subsequent surface complexation reactions, to a redox change from oxic to sub oxic conditions. A redox gradient is commonly encountered in nature, observed in wetlands and from flooding sediments. These findings can be applied to a contaminant management plan, and may be important when considering the anticipated precipitation pattern changes due to global climate change. The overall goal of this study was to characterize mineralogical structural changes and solubilities of the solid phase iron sorbate host and the dissolved constituents (incl. nutrients and contaminants) in suboxic environments. Generally, suboxic environments are found in wetlands and submerged soils. Because wetlands accumulate dissolved ions from a vast watershed, a geochemical response to a hydrologic perturbation will likely affect contaminant and nutrient cycling in the region, and should be included in any management response. Iron is one of the most abundant elements in soils and the most abundant redox active element in natural systems, is generally dissolved as a reduced species (FeII) and insoluble as an oxidized species (FeIII). Therefore, iron transitions are principally controlled by the availability of oxygen. The result is a variety of iron oxide and hydroxide mineral phases that are stable and meta-stable under different soil PO2 conditions. Due to the transient variability between the aqueous Fe(II) and solid phase Fe(III) redox states, iron plays a major role in controlling the nutrient and contaminant cycling in subsurface environment. This research has investigated green rusts that may form at the redox boundary between fully oxidized and sub oxic sediments (Root et al. 2007, 2009). A primary goal of this research was to increase the scientific knowledge base concerning arsenic clean up and remediation, removal from the drinking water supply, and sequestration in the solid phase thereby isolating arsenic from uptake into the biota.

Download or read book Effects of Microbially Mediated Iron and Sulfur Cycling on Arsenic Mobility written by Samantha L. Saalfield and published by . This book was released on 2009 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Microbial Oxidation of Arsenite in Anoxic Environments Impacts on Arsenic Mobility written by and published by . This book was released on 2008 with total page 674 pages. Available in PDF, EPUB and Kindle. Book excerpt: AbstractArsenic (As) contamination of groundwater and surface water is a worldwide problem. Exposure to arsenic in drinking water is an important current public health issue. Arsenic is well known for its carcinogenic and teratogenic effects. The U.S. Environmental Protection Agency (USEPA) has recently enacted a stricter drinking water standard for arsenic that lowers the maximum contaminant level (MCL) from 50 to 10 ug l-1. Localized elevated As concentrations in groundwater or surface water have been attributed to the natural release of As from the weathering of As bearing minerals. Microbial reduction of arsenate (As(V)) to arsenite (As(III)) and ferric (hydr)oxides to Fe(II) is hypothesized to be the dominant mechanisms of As mobilization in subsurface environments. If oxidizing conditions can be restored, As can be immobilized by the formation of As(V) and ferric (hydr)oxides. As(V) is more strongly adsorbed than As(III) at circumneutral conditions by common non-iron metal oxides in sediments such as those of aluminum. Ferric (hydr)oxides have strong affinity for both As(III) and As(V) in circumneutral environments. Oxygen can be introduced into the anaerobic zone by injection of gaseous O2 to promote oxidation reactions of As(III) and Fe(II), but O2 is poorly soluble and chemically reactive and thus difficult to distribute in the subsurface. Nitrate or chlorate can be considered as alternative oxidants with advantages over elemental oxygen due to their high aqueous solubility and lower chemical reactivity which together enable them to be better dispersed in the saturated subsurface. The objective of this study is to evaluate the importance of anoxic oxidation of As(III) to As(V) by anaerobic microorganisms such as chemolithotrophic denitrifying bacteria and chlorate respiring bacteria in the biogeochemical cycle of arsenic. This study also investigated a arsenic potential bioremediation strategy based on injecting nitrate or chlorate into contaminated groundwater and surface water under anaerobic conditions. In this study, denitrification or chlorate reduction linked to the oxidation of As(III) to As(V) was shown to be a widespread microbial activity in anaerobic sludge and sediment samples that were not previously exposed to arsenic contamination. The biological oxidation of As(III) utilizing nitrate or chlorate as sole electron acceptor was feasible and stable over prolonged periods of operation in continuous-flow anaerobic bioreactors. Evidence for the complete denitrification was demonstrated by direct measurement of N2 formation dependent on As(III) addition. Also complete chlorate reduction to chloride was attributable to the oxidation of As(III). A 16S rRNA gene clone library characterization of enrichment cultures indicated that the predominant phylotypes responsible for As(III) oxidation linked to denitrification were from the genus Azoarcus and the family Comamonadaceae. A bioremediation strategy was explored that is based on injecting nitrate to support the microbial oxidation of Fe(II) and As(III) in the subsurface as a means to immobilize arsenic. Two models were utilized to illustrate the mechanisms of As removal. 1)Sediment columns packed with activated alumina were utilized to demonstrate the role of nitrate in supporting microbial As(III) oxidation and arsenic mobility in anoxic sediments containing mostly non-iron oxides;2)Sand-packed columns were used to simulate natural anaerobic groundwater and sediment systems with co-occurring As(III) and Fe(II) in the presence or absence of nitrate. Microbial oxidation by denitrifying microorganisms lead to the formation of ferric (hydroxides) which adsorbed As(V) formed from As(III)-oxidation. The studies presented here demonstrate that anoxic microbial oxidation of As(III) and Fe(II) linked to denitrification significantly enhance the immobilization of As in the anaerobic subsurface environments.

Download or read book Soil Health and Climate Change written by Bhupinder Pal Singh and published by Springer Science & Business Media. This book was released on 2011-07-24 with total page 399 pages. Available in PDF, EPUB and Kindle. Book excerpt: “Soil Health and Climate Change” presents a comprehensive overview of the concept of soil health, including the significance of key soil attributes and management of soil health in conventional and emerging land use systems in the context of climate change. Starting with a review of the physical, chemical and biological indicators of soil health and their significance for monitoring the impacts of climate change, this book then focuses on describing the role of soil structure, pH, organic matter, nitrogen, respiration and biota in sustaining the basic functions of soil ecosystems, and their anticipated responses to climate change. Further topics include the management of cropping, pastoral, and forestry systems, and rehabilitated mine sites, with a focus on mitigation of and adaptation to climate change impacts. Finally, the opportunities and potential risks of organic farming, biochar and bioenergy systems, and their ability to sustain and even enhance soil health, are discussed.

Download or read book Environmental Remediation Technologies for Metal Contaminated Soils written by Hiroshi Hasegawa and published by Springer. This book was released on 2015-09-28 with total page 257 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a comprehensive and detailed description of remediation techniques for metal-contaminated soils derived from both natural processes and anthropogenic activities. Using a methodical, step-by-step presentation, the book starts by overviewing the origin of toxicants and the correlated comparative extent of contamination to the environment. The legal provisions as proposed or applied in different countries are then discussed to explain the global regulatory situation regarding soil contamination and the extent of consequent concern. The core part of this publication describes the major techniques for in situ or ex situ treatment of the contaminated soil to meet the regulatory limits. Finally, risk evaluation is incorporated, giving special attention to possible impacts during or after implementation of the remediation strategies. The intrusion of metals in soils mostly occurs from various anthropogenic activities, e.g., agricultural practices, industrial activities, and municipal waste disposal. The volumes of metal-contaminated soil are becoming greater than before and are ever-increasing due to rapid urbanization, intensified industrialization, and/or population booms in certain parts of the world. Hence, the options previously proposed, such as isolation of the contaminated site or movement of the contaminated mass to a secure disposal site after excavation, are becoming unsuitable from the economic point of view, and instead, decontamination alternatives are preferred. This book will help readers such as scientists and regulators to understand the details of the remediation techniques available to deal with the soils contaminated by toxic metals.

Download or read book Arsenic Pollution written by Peter Ravenscroft and published by Wiley-Blackwell. This book was released on 2009-03-09 with total page 624 pages. Available in PDF, EPUB and Kindle. Book excerpt: 'Arsenic Pollution' summarises the research on the distribution and causes of arsenic pollution, its impact on health and agriculture, and solutions by way of water supply, treatment, and water resource management.

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.

Download or read book Arsenic Treatment Technologies for Soil Waste and Water written by and published by DIANE Publishing. This book was released on 2002 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Impact of Redox Potential and Salinity on Arsenic Cycling and Mobility in Iron Oxide Systems written by Joshua Zachery Sanchez and published by . This book was released on 2022 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: Additional experiments are needed to further elucidate the role of seawater in arsenate adsorption at a high pH and its effect on the arsenate-iron oxide binding complex. Also, further investigation into the role of SO42- on As and Fe cycling throughout a shifting redox potential is needed.