Engineering Commons^™

Addressing Mercury Contamination From Artisanal Gold Mining In Colombia: Pollution Exposure, Health Risk, And Educational Efforts In The Communities Of La Toma, Colombia, Kelli Mccourt

All Dissertations

Artisanal and small-scale gold mining (ASGM) has become a primary environmental and public health concern in the region of Colombia known as Alto Cauca. The predominantly Afro-descendent communities of Yolombó and La Toma in Alto Cauca have experienced pollution linked to the use of mercury in the ASGM process. For the past decade, mercury has emerged as a contaminant of increasing concern in the communities due to its toxicity and ability to bioaccumulate and biomagnify. Likewise, mining in the region raises concerns over the leaching of metals into local waters. Given the complexity of risk and pollution in the communities, …

Diagnostic Gold Deportment Studies And Leaching Behaviour Of Small-Scale Gold Mining Tailings From Eastern Region, Ghana, Ishmael Quaicoe, Martin Beyuo, Solomon Quaicoe, Nikao A. Lasidzi

Journal of Sustainable Mining

Artisanal and small-scale gold mining (ASGM) sector employs about 80% of the mining workforce but only contributes about 20-30% of Ghana’s gold production. The low gold production is linked to low recoveries associated with the activities because ofinadequate understanding of the chemical, mineralogical and metallurgical characteristics of the ores. This study examined the metallurgical characteristics of typical small-scale gold mining tailings to understand their grinding characteristics, gold deportment and cyanidation behaviour. The gold deportment results showed that 96.1% of the gold in the samples is free milling (can be leached directly with cyanide and recovered through carbon adsorption), whilst the …

Bioaccumulation Of Polychlorinated Biphenyl Compounds And Mercury In A Mining Impacted Aquatic Ecosystem, Michelle Bollini

Dissertations, Master's Theses and Master's Reports

The Keweenaw area continues to be influenced by the century of copper mining that ended nearly 50 years ago. This project is focused on Torch Lake, an aquatic ecosystem that has been heavily impacted by mining waste disposal. The watershed has been impaired by mine discharge and tailings, smelter and smokestack plumes, and poor waste disposal practices. The lake is listed as a Great Lakes Area of Concern with beneficial use impairments of restrictions on fish consumption and a degraded benthic community. Polychlorinated biphenyl compounds (PCBs) and methylmercury (MeHg) are persistent, bioaccumulative, and toxic substances (PBTs). These contaminants pose threats …

Terrestrial Laser Scanning Technology For Measuring Streambank Retreat Along East Fork Poplar Creek And Calculating The Effect On Mercury Release., José L. Martínez Collado

Masters Theses

Mercury (Hg) is a globally distributed inorganic pollutants of human concern. The high toxicity is mainly related to the capacity of Hg species to accumulate and biomagnify along aquatic food webs. Along East Fork Poplar Creek (EFPC), erosion represents the principal mercury input into the local waters, eventually reaching humans through the food chain. This research project aimed to monitor streambank erosion along a mercury-contaminated creek using Light Detention and Ranging (Lidar) technology and erosion pins. A Terrestrial Laser Scanner (TLS) was used to generate high-resolution point clouds from August 2020 to January 2021 across nine streambank locations to detect …

Two-Dimensional Nanomaterials And Their Composites For Electrochemical Detection Of Toxic Mercury Ions In Water, Md Tawabur Rahman

Electronic Theses and Dissertations

The presence of trace amounts of mercury ion (Hg²⁺) in drinking water has a detrimental effect on human health. The development of an electrochemical sensor for Hg²⁺ detection is still challenging to obtain ultra-trace sensitivity, excellent selectivity, wide Linear Detection Ranges (LDRs), and ultra-low detection limit. This work presents an electrochemical sensor based on two-dimensional nanomaterials and their composites for the enhanced sensing of Hg²⁺ in water. Graphene oxide (GO)-silver nanowires (AgNWs) composite and metallic 1T phase tungsten disulfide (WS2) microflowers were utilized for the fabrication of electrochemical sensors using drop-casting. Under the optimized experimental conditions, …

Propuesta De Protocolo De Incautación, Transporte Y Almacenamiento De Mercurio En Cumplimiento De La Ley 1658 De 2013 Para La Dicar, Daniel Alejandro Cepeda Archila, Laura Vanessa Parga Hernández

Ingeniería Ambiental y Sanitaria

La problemática, que se aborda en este estudio, atañe el procedimiento de incautación, trasporte y almacenamiento del mercurio. Esta sustancia, por su naturaleza tóxica, exige condiciones especiales para su manejo, por parte de la Dirección de Carabineros de la Policía Nacional (DICAR), como ente encargado de realizar los operativos, en concordancia con la Ley 1658 de 2013. Por ello, esta investigación pretende diseñar un protocolo como herramienta estratégica y conveniente que responda al fortalecimiento del programa de incautación de Mercurio por parte de la fuerza pública y como parte esencial para el desarrollo de las funciones encomendadas a la unidad …

Status And Remediation Of Mercury In Fish And Aquatic Ecosystems, Geoffrey Dean Millard

Dissertations - ALL

Mercury is a known neurotoxin which can bioaccumulate and biomagnify as methylmercury, causing significant human and ecological impacts. New York State and the surrounding region is impacted by mercury in complex ways as some areas are recovering from the effects of acidic deposition while the entire region is increasingly influenced by climate change. In order to better understand the drivers and trends of mercury dynamics in New York State, my research was conducted in three phases: 1) the impact of lime (calcium carbonate) additions on mercury cycling in small acid-sensitive headwater streams of the Adirondack State Park; 2) applied advanced …

A Historical Sedimentary Record Of Mercury In A Shallow Eutrophic Lake: Impacts Of Human Activities And Climate Change, Hanxiao Zhang, Shouliang Huo, Kevin M. Yeager, Beidou Xi, Jingtian Zhang, Fengchang Wu

Earth and Environmental Sciences Faculty Publications

Mercury and its derivatives are hazardous environmental pollutants and could affect the aquatic ecosystems and human health by biomagnification. Lake sediments can provide important historical information regarding changes in pollution levels and thus trace anthropogenic or natural influences. This research investigates the 100-year history of mercury (Hg) deposition in sediments from Chao Lake, a shallow eutrophic lake in China. The results indicate that the Hg deposition history can be separated into three stages (pre-1960s, 1960s–1980s, and post-1980s) over the last 100 years. Before the 1960s, Hg concentrations in the sediment cores varied little and had no spatial difference. Since the …

Guía Metodológica Para El Muestreo De Suelos Contaminados Con Mercurio Por Minería Del Oro En Colombia, Laura Ximena Ariza Torres, Tatiana Andrea Camargo Melo

Ingeniería Ambiental y Sanitaria

En este trabajo se realizó una revisión bibliográfica sobre la contaminación del mercurio por minería del oro y guías de muestro para suelos contaminados por este metal, por lo cual se logró determinar que en Colombia el método de extracción del oro más usado en la minería artesanal es la amalgamación con mercurio, este factor ha generado problemas de contaminación a gran escala en diferentes partes del país, afectando comunidades y ecosistemas, la escasa información respecto a protocolos y / o guías de campo que están relacionadas específicamente para suelo contaminando en Colombia hace necesario el Fortalecer respecto a la …

A Model To Predict Concentrations And Uncertainty For Mercury Species In Lakes, Ashley Hendricks

Dissertations, Master's Theses and Master's Reports

To increase understanding of mercury cycling, a seasonal mass balance model was developed to predict mercury concentrations in lakes and fish. Results indicate that seasonality in mercury cycling is significant and is important for a northern latitude lake. Models, when validated, have the potential to be used as an alternative to measurements; models are relatively inexpensive and are not as time intensive. Previously published mercury models have neglected to perform a thorough validation. Model validation allows for regulators to be able to make more informed, confident decisions when using models in water quality management. It is critical to quantify uncertainty; …

Evaluation, Improvement, And Application Of Models Of Environmental Fate And Transport Of Atmosphere-Surface Exchangeable Pollutants (Aseps), Tanvir Khan

Dissertations, Master's Theses and Master's Reports

Certain toxic, semivolatile chemicals, also known as atmosphere-surface exchangeable pollutants (ASEPs) are emitted into the environment from anthropogenic activities and natural sources. This dissertation focused on the (i) evaluation and improvement of dry particle deposition and atmosphere-surface exchange parameterizations of ASEPs for use in chemical transport models (CTMs), and (ii) application of a dynamic multimedia model to examine recovery of Lake Superior from historical inputs of polychlorinated biphenyl (PCB) compounds (a class of ASEPs) contamination.

Current knowledge has been inadequate to propose quantitative measures of the relative performance of available dry particle deposition parameterizations. In Chapter 1 of this dissertation, …

Study Of Poisoning Mechanism Of Hg And As On V2o5–Wo3/Tio2 Scr De-Nox Catalysts, Qingcai Liu, Ming Kong, Lu Yao, Shan Ren, Jian Yang

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.

Elevational And Seasonal Patterns In Methylmercury Production Across The Montane Landscape Of Whiteface Mountain In The Adirondack Region Of New York, Jacqueline R. Gerson

Dissertations - ALL

Global mercury contamination results from direct primary atmospheric and secondary legacy emissions, which can be deposited to ecosystems, converted to methylmercury, and bioaccumulated along food chains. I examined soil samples collected across an elevational gradient on Whiteface Mountain in the Adirondack region of New York State to determine spatial patterns in methylmercury concentrations across a forested montane landscape. I found that soil methylmercury concentrations were highest in the mid-elevation coniferous zone (0.39 ± 0.07 ng/g) compared to the alpine (0.28 ± 0.04 ng/g) and deciduous zones (0.17 ± 0.02 ng/g), while the percent mercury as methylmercury in soils decreased linearly …

Response Of Mercury In A Forest Stream To Lime Application: Accelerated Watershed Recovery, Geoffrey Dean Millard

Dissertations - ALL

Following decreases in acid deposition, some impacted surface waters in northern Europe and the northeastern USA are beginning to recover. The resultant increases in pH in these waters has coincided with increased dissolved organic carbon concentrations, which is also correlated with increases in both total mercury and methylmercury concentrations. Understanding how ecosystem mercury dynamics respond to recovery from acid deposition has important implications for fisheries and human exposure. Honnedaga Lake is one of seven lakes in the Adirondack Park of New York State with a heritage Brook trout (Salvelinus fontinalis) population, making the bioavailability and trophic transfer of mercury (Hg) …

Novel Applications Of Electrostatic Precipitators In Coal - Biomass Combustion Systems, He Jing

McKelvey School of Engineering Theses & Dissertations

Pulverized coal combustion is an important source of electricity production worldwide. However, it is also a primary air pollution emission (particulate matters, mercury, etc.) source. Electrostatic precipitators (ESPs) are widely used in coal-fired power plants to control particulate matters. This dissertation contributes in the study of the pollution formation from coal combustion processes and pollution control based on ESPs in the following three aspects: (1) explore novel applications of ESPs in particulate matters and mercury removal; (2) develop and evaluate an compact electrostatic precipitator for sampling purpose, which can support offline fly ash particle analysis; (3) study the submicrometer particle …

Mercury Removal From Aqueous Solution Using Natural, Synthetic, And Modified Zeolites, Mahshid Attari

Electronic Thesis and Dissertation Repository

Mercury has been recognized as one of the most hazardous heavy metals. The discharge of effluents containing mercury in soil, sediments and water can inflict an irreversible harm to the environment and human health. In this work, zeolitized coal fly ash as well as gold and gold-iron modified zeolites were successfully employed for mercury removal from a typical industrial wastewater. X-ray diffraction (XRD), thermo-gravimetrical analyses (TGA), surface area measurement (BET), and scanning electron microscopy (SEM-EDX) were utilized to explore the characteristics of the raw and modified zeolites. A pseudo-second-order kinetic model was identified to best represent the kinetic data for …

Production Of Activated Carbons From Pyrolytic Char For Environmental Applications, Anastasia Colomba

Electronic Thesis and Dissertation Repository

Biomass pyrolysis has the potential to become a major component of future biorefineries, since biomass is cracked to produce gases, liquid products (bio-oil) and solid products (bio-char). In order for the process to be economically feasible, it is necessary to obtain the maximum value from each stream, thus no by-product can be regarded as a waste.

Bio-char is normally regarded as a by-product of fast pyrolysis, which is optimized to target bio-oil production. However, there are many potentially attractive applications for it: for example, it can be used for the production of activated carbons, which are the most commonly used …

Development Of Bamboo‐Derived Sorbents For Mercury Removal In Gas Phase, Naved Siddiqui, Jarlen Don, Kanchan Mondal, Ajay Mahajan

Dr. Ajay Mahajan

Activated carbon sorbents were synthesized from bamboo precursors by carbonization in an inert atmosphere followed by physiochemical activation with carbon dioxide and finally acidulation in hydrochloric acid. Bamboo strips with and without the epidermal tissue (bark) were used. The morphology and specific surface area changes due to the treatment were analysed. The adsorption characteristics of these sorbents after each stage of treatment were also analysed and the data were correlated to the changes in the physical characteristics of the sorbents. Kinetic studies were conducted on these samples. The adsorption equilibrium and kinetics of elemental mercury adsorption on these carbons were …

The Effects Of Watershed Liming On Mercury Concentrations And Stocks In Soil Of Woods Lake, New York, Zhenni Xie

Theses - ALL

Abstract

In acid-impacted forests, lime has been applied to neutralize acidity and mitigate acidification of soil and surface waters. However, few studies have evaluated the effects of liming on watershed mercury processes and transport. I investigated the effects of liming on mercury, organic carbon, and sulfur concentrations and stocks in forest soil 19 years after the application of lime to the Woods Lake Watershed, Adirondack Park, New York, USA (42o52' N, 71o58' W). The mercury, organic carbon, and sulfur stocks were significantly greater in the forest floor of limed areas (24.5 vs. 11.1 Hg g/ha for Oe and 31.6 vs. …

Mercury Transport And Fluxes In The Lake Ontario Basin, Joseph Steven Denkenberger

Dissertations - ALL

In this dissertation I assess mercury dynamics in the Lake Ontario Basin. In four interrelated phases, ecosystem mercury concentrations and fluxes were analyzed at increasing scales. Each phase is presented in order of increasing scale, starting with a reach-by-reach analysis in the Seneca River in New York, then moving up to an analysis of the Lake Ontario watershed, followed by an assessment of Lake Ontario, and culminating with an estimate of atmospheric mercury exchange for the entire Great Lakes Basin.

Phase 1 of my research is a multi-year study exploring mercury (Hg) dynamics in the Three Rivers system, with particular …

Effects Of Environmental Heavy Metals On Neural Stem Cell Survival And Differentiation, Sameera S. Clev Tasneem

ETD Archive

No abstract provided.

Development Of An Enhanced Hydro-Geochemical Model To Address Mercury-Speciation Fate And Transport In Aquatic Environments, Nantaporn Noosai

FIU Electronic Theses and Dissertations

An awareness of mercury (Hg) contamination in various aquatic environments around the world has increased over the past decade, mostly due to its ability to concentrate in the biota. Because the presence and distribution of Hg in aquatic systems depend on many factors (e.g., pe, pH, salinity, temperature, organic and inorganic ligands, sorbents, etc.), it is crucial to understand its fate and transport in the presence of complexing constituents and natural sorbents, under those different factors. An improved understanding of the subject will support the selection of monitoring, remediation, and restoration technologies.

The coupling of equilibrium chemical reactions with transport …

Soil Mercury And Its Response To Atmospheric Mercury Deposition Across The Northeastern United States, Xue Yu, Charles T. Driscoll, Richard A. F. Warby, Mario Montesdeoca, Chris E. Johnson

Civil and Environmental Engineering

Terrestrial soil is a large reservoir of atmospherically deposited mercury (Hg). However, few studies have evaluated the accumulation of Hg in terrestrial ecosystems in the northeastern United States, a region which is sensitive to atmospheric Hg deposition. We characterized Hg and organic matter in soil profiles from 139 sampling sites for five subregions across the northeastern United States and estimated atmospheric Hg deposition to these sites by combining numerical modeling with experimental data from the literature. We did not observe any significant relationships between current net atmospheric Hg deposition and soil Hg concentrations or pools, even though soils are a …

Integration Of A Sedimentation Module To A Hydrologic Model And Its Application To A Mercury Tmdl Analysis, Lilian Marrero

FIU Electronic Theses and Dissertations

This research is part of continued efforts to correlate the hydrology of East Fork Poplar Creek (EFPC) and Bear Creek (BC) with the long term distribution of mercury within the overland, subsurface, and river sub-domains. The main objective of this study was to add a sedimentation module (ECO Lab) capable of simulating the reactive transport mercury exchange mechanisms within sediments and porewater throughout the watershed. The enhanced model was then applied to a Total Maximum Daily Load (TMDL) mercury analysis for EFPC. That application used historical precipitation, groundwater levels, river discharges, and mercury concentrations data that were retrieved from government …

Deposition And Fate Of Atmospheric Mercury In Forested Landscapes Of The Adirondack Park, Ny, Bradley Blackwell

Civil and Environmental Engineering - Dissertations

In this dissertation, I investigated the deposition and fate of atmospheric mercury (Hg) to forested landscapes of the Adirondack region in Upstate New York. Despite the fact that forests are the dominant land cover in North America, there has been relatively little research on the deposition, transport, and fate of Hg within forested ecosystems. The objective of this dissertation was to quantify pathways of Hg deposition in forested sites in the Adirondack Park and to examine spatial and geographic patterns of Hg deposition and fate.

The research for this dissertation was conducted in three phases. In Phase One, I compared …

Mercury Concentrations In Tropical Resident And Migrant Songbirds On Hispaniola, Jason M. Townsend, Christopher C. Rimmer, Charles T. Driscoll, Kent P. Mcfarland, Eduardo E. Inigo-Elias

Civil and Environmental Engineering

Despite growing concerns over mercury (Hg) exposure to humans and wildlife on a global scale, little is known about Hg bioaccumulation in the New World tropics. From 2005 to 2011, we monitored Hg concentrations in blood of nine avian species occupying a geographic range of tropical wet broadleaf sites on the island of Hispaniola, including eight passerines (two Nearctic- Neotropical migrant and six resident species) and one top order predatory accipiter. Invertivorous songbirds were further differentiated by foraging guild, with six species of groundforagers and two species of foliage-gleaners. Blood Hg concentrations were orders of magnitude higher in birds sampled …

Investigation Of Mercury Use, Release, Deposition, And Exposures In The Tampa Bay Area, Ryan Algernon Michael

USF Tampa Graduate Theses and Dissertations

I investigate the links between mercury use, release, deposition, and population exposure in Tampa Bay, with the focus of identifying levers for reducing population mercury exposures. To achieve this, I investigated the trends in mercury use and release by products and processes in the Tampa Bay area using a Material Flow Analysis. Analysis of USEPA National Emissions Inventory data over time (1999 - 2008) identified relevant air source emission categories, and explored and compared state and regional trends in mercury emissions. To understand source contributions to wet deposited mercury in the Tampa Bay area, I analyzed trends in mercury deposition …

A Synthesis Of Rates And Controls On Elemental Mercury Evasion In The Great Lakes Basin, Joseph S. Denkenberger, Charles T. Driscoll, Brian A. Branfireun, Chris S. Eckley, Mark Cohen, Pranesh Selvendiran

Civil and Environmental Engineering

Rates of surface-air elemental mercury (Hgo) fluxes in the literature were synthesized for the Great Lakes Basin (GLB). For the majority of surfaces, fluxes were net positive (evasion). Digital land-cover data were combined with representative evasion rates and used to estimate annual Hgo evasion for the GLB (7.7 Mg/yr). This value is less than our estimate of total Hg deposition to the area (15.9 Mg/yr), suggesting the GLB is a net sink for atmospheric Hg. The greatest contributors to annual evasion for the basin are agricultural (~55%) and forest (~25%) land cover types, and the open water of the Great …

Nutrient Supply And Mercury Dynamics In Marine Ecosystems: A Conceptual Model, Charles T. Driscoll, Celia Y. Chen, Chad R. Hammerschmidt, Robert P. Mason, Cynthia C. Gilmour

Civil and Environmental Engineering

There is increasing interest and concern over the impacts of mercury (Hg) inputs to marine 32 ecosystems. One of the challenges in assessing these effects is that the cycling and trophic 33 transfer of Hg are strongly linked to other contaminants and disturbances. In addition to Hg, a 34 major problem facing coastal waters is the impacts of elevated nutrient, particularly nitrogen 35 (N), inputs. Increases in nutrient loading alter coastal ecosystems in ways that should change 36 the transport, transformations and fate of Hg, including increases in fixation of organic carbon 37 and deposition to sediments, decreases in the …

Nutrient Supply And Mercury Dynamics In Marine Ecosystems: A Conceptual Model, Charles T. Driscoll, Celia Y. Chen, Chad R. Hammerschmidt, Robert P. Mason, Cynthia C. Gilmour, Elsie M. Sunderland, Ben K. Greenfield, Kate L. Buckman, Carl H. Lamborg

Civil and Environmental Engineering

There is increasing interest and concern over the impacts of mercury (Hg) inputs to marine ecosystems. One of the challenges in assessing these effects is that the cycling and trophic transfer of Hg are strongly linked to other contaminants and disturbances. In addition to Hg, a major problem facing coastal waters is the impacts of elevated nutrient, particularly nitrogen (N), inputs. Increases in nutrient loading alter coastal ecosystems in ways that should change the transport, transformations and fate of Hg, including increases in fixation of organic carbon and deposition to sediments, decreases in the redox status of sediments and changes …