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 processes in the model PHREEQC offers an advantage in simulating and predicting the fate and transport of aqueous chemical species of interest. Thus, a great variety of reactive transport problems could be addressed in aquatic systems with boundary conditions of specific interest. Nevertheless, PHREEQC lacks a comprehensive thermodynamic database for Hg. Therefore, in order to use PHREEQC to address the fate and transport of Hg in aquatic environments, it is necessary to expand its thermodynamic database, confirm it and then evaluate it in applications where potential exists for its calibration and continued validation. The objectives of this study were twofold: 1) to develop, expand, and confirm the Hg database of the hydrogeochemical PHREEQC to enhance its capability to simulate the fate of Hg species in the presence of complexing constituents and natural sorbents under different conditions of pH, redox, salinity and temperature; and 2) to apply and evaluate the new database in flow and transport scenarios, at two field test beds: Oak Ridge Reservation, Oak Ridge, TN and Everglades National Park, FL, where Hg is present and is of much concern. Overall, this research enhanced the capability of the PHREEQC model to simulate the coupling of the Hg reactions in transport conditions. It also demonstrated its usefulness when applied to field situations.

This work was focused on determination of mobility of mercury and its content in materials from each part of the wine production process. The aim of this work was to establish the most suitable analytical method for determination and evaluation of changes in content of mercury during the production process. Samples of soil, biomass, vine wood, vine leaves, berries, grapes, rough wine and cider sediment of red wine and also four liquid samples of white wine were analyzed. All the samples originated from the area of Malé Žernoseky and Rudoltice nad Bílinou, white wine samples were collected in Chrámce u Mostu in the northern part of the Czech Republic. Analyzer AMA 254 was used for determination of mercury in solid samples and liquid samples had to be prearranged by PSA analyzer. This analytical approach was not so sufficient and mercury from liquid samples had to be captured by gold-coated amalgamator in first step and then analyzed by AMA 254. Obtained results confirmed interception of mercury mostly in leaves and in the grapes peelings. The grapes from Rudoltice contained 0,0022 mg/kg in dry mass and further processed wine grapes contained 0,0068 mg/kg in dry mass. The lowest content of mercury was in cider and completed wine contained less mercury then the rough wine. Unfiltrated cider from Chrámce has...

Mercury (Hg) is a globally distributed toxicant that has been shown to have negative effects on birds. in the United States, avian taxa have been shown to possess high Hg concentrations in the northeast, Great Lakes and Everglades ecosystems; however, few studies have measured avian Hg concentrations in other geographic regions. Previous studies have documented high Hg concentrations in multiple organisms in east Texas, but birds were not included in these studies. the main objective of the present study was to quantify Hg concentrations in birds in differing trophic levels at Caddo Lake and Lake Lewisville, TX. Results suggest that Hg concentrations may be high enough to negatively impact some bird taxa, particularly those at high trophic levels, residing at both Caddo Lake and Lake Lewisville.

The differential and total inelastic cross sections for electron-mercury atom collisions were calculated using the Born approximation together with the Ochkur approximation for the transitions (^1S_0 -> ^3P_0), (^1S_0 -> ^3P_2), (^3P_0 -> ^1S_0), and (^3P_2 -> ^1S_0) at one eV energy intervals from 1 eV - 33 eV above threshold. A reprint of work previously published containing values for polarizabilities of all the atoms is contained in Appendix B.

Methylmercury (MeHg) is a global pollutant and potent neurotoxin that bioaccumulates in aquatic and terrestrial foodwebs. As such, predicting the fate of MeHg in the environment is important in addressing ecosystem and human health concerns. Pollution that results from mining activities (i.e. ore roasting and smelting) is one way in which geochemistry of lakes can be altered, in turn altering the cycling of mercury (Hg) overall and the kinetics of MeHg production and bioaccumulation. My thesis is focused on examining the effect of different pollution gradients on the cycling of Hg at two different sites impacted by legacy mining in Canada. In Yellowknife (Northwest Territories, Canada) I assessed the effect of sulfate and arsenic (As) emissions on the production of MeHg in lake sediments, while in Sudbury (Ontario, Canada) I examined the effect of selenium (Se) emissions on the bioaccumulation of Hg and MeHg in freshwater biota. In Yellowknife, an environment polluted with both sulfate and As from mining activities, lakes were sampled using a factorial design which controlled for environmental variables known to affect MeHg production (i.e. sulfate, iron, productivity, pH, and dissolved organic matter). We used stable Hg isotope tracers to quantify Hg methylation and demethylation rate constants in sediments. Results showed that %MeHg in the water is best correlated with sulfate concentrations, while the rate at which Hg is methylated (Km) in sediments is negatively correlated with total As, and positively correlated with dissolved organic carbon, total phosphorus, and %MeHg in the water. Furthermore, a detailed examination of a lake with representative limnological characteristics of the area showed that addition of sulfate and organic carbon does increase the production of MeHg in the sediments, while addition of arsenate (0 to 10 mM) showed significant decrease in MeHg production, regardless of sulfate concentrations. Next, Se emissions in Sudbury (Ontario, Canada) correlated with lower total Hg and MeHg in tissues of zooplankton, amphipods (Hyalella azteca), mayflies (Stenonema femoratum), and young-of-the-year perch (Perca flavescens). However, despite ten years of emission reductions, results show that total Se concentrations in the majority of lakes have increased, most likely due to the long residence time of Se in the watershed and the water column. Consequently, Se continues to exhibit a protective effect on total Hg and MeHg bioaccumulation in biota, even a decade after emissions have greatly decreased. Canada’s numerous mining operations have left a legacy of pollution and it is important to understand the effects of these pollutants on the biogeochemistry of surrounding lakes. The results from my thesis demonstrate how mining emissions can alter the kinetics and bioaccumulation of MeHg in freshwater lakes, highlighting the complexity of Hg cycling in response to mining activities. My thesis is an important step in identifying and modeling the controls of MeHg production and bioaccumulation in environments impacted by emissions from mining operations.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第22430号 / 工博第4691号 / 新制||工||1732(附属図書館) / 京都大学大学院工学研究科都市環境工学専攻 / (主査)教授 高岡 昌輝, 教授 米田 稔, 准教授 大下 和徹 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

Fish and wildlife were randomly sampled in Utah from pre-selected x areas and analyzed for levels of total mercury, dieldrin, DDT, and DDE. Levels were well within consumptive tolerance or guildeline limits except for mercury levels of fish in Willard Bay Reservoir. PCB's were also identified in a large proportion of samples. None of the chukars, 6 percent of the pheasants, 4 percent of the waterfowl, and none of the fish sampled, excluding Willard Bay Reservoir, were above the 0.5 ppm guideline level for mercury established by the Food and Drug Administration. Seventy-seven percent of the fish sampled from Willard Bay Reservoir were above the 0.5 ppm guideline level. Only one duck (2 percent) was above the maximum permissible concentration for dieldrin. All of the chukars, pheasants, other waterfowl, and fish were well below human consumptive tolerance limits for dieldrin and DDT + DDE. It is recommended that studies be initiated to more closely define possible sources of mercury and the health hazard involved in consumption of these fish.

A lead sensitive indicator electrode was constructed with a 70 percent lead and 30 percent mercury amalgam billet. Sulfate concentrations in pure solutions, natural waters, and soil saturation extracts were determined potentiometrically using the lead-mercury amalgam indicator electrode and a standard calomel reference electrode. Sulfate concentrations over the range 0.4 to 20 milliequivalents sulfate per liter were determined with an automatic titrator and compared to a turbidimetric method for accuracy and precision. The values obtained by the two methods from twelve saturation extracts and three subsurface drainage waters were not significantly different and the potentiometric method was generally more precise. The automatic sulfate titration method has the advantages of increased sensitivity and speed.

Abstract Organic derivatives of tin, lead, mercury are the most widely distributed organometallic ecotoxicants in the environment. While some of these organometallic compounds exist in the environment as a result of direct discharge, anthropogenic emissions alone cannot explain the ubiquity, for example, of the organomercury and organolead compounds in marine and fresh waters, sediments and biota. It is known that some organometallic compounds are formed via a bioconversion from the inorganic contaminants. Depending on the source, they can enter the environment in varied forms inorganic species of different stability. These can be bio-converted further by environmental biota; for instance metals such as tin and lead can be discharged into the environment in the form of organometallic species which can undergo further transformation. Determination of organometallics in environmental and biological samples is difficult due to matrix effect and their low concentrations. Separation and preconcentration is necessary to enhance final determination. Speciation studies are even more complicated. Speciation is an important aspect and gives information about bioavailability of the metal thus their toxicity. This work focused on the development of a method for speciation of organospecies of tin, lead and mercury. A new derivatisation agent has been synthesised and used successfully. SLM probe extraction has been exposed to a new matrix. Different environmental samples have been analysed for organo-species of tin and lead and their pathways predicted. The SLM probe extraction gives the advantage of carrying out several extractions, reduction of the amount of solvent used and avoidance of emulsion problems. A simple system has been developed and applied successfully on organotin and organolead extraction from aqueous environmental sample. For reproducibility of the results, pH, salinity, stirring rate and extraction time were optimized. An analytical method for simultaneous in situ ethylation, using new derivatisation agent bromomagnesium tetraethylborate (Et4BMgBr), of organotin and organomercury compounds in sediment samples was developed. The determination of mercury and tin compounds is achieved by species-specific isotope dilution, derivatisation and gas chromatography – inductively coupled plasma mass spectrometry (GC-ICP-MS). In derivatisation, pH and the amount of derivatisation agent were studied. Percentage recovery and accuracy of the method was confirmed by comparison of experimental results with sediment and plant certified reference material (IAEA 405 for sediment and CRM 279 for plant). Although organolead compounds as a gasoline additive are banned in most countries, in some regions, lead is still added to gasoline in varying proportions of different tetraalkyllead compounds and contamination by organolead compounds is still present at different places, e.g.: lead alkyl manufactures The use of both tetraalkyllead and butyltin is banned (tetraalkyllead as gasoline additive and butyltin in antifouling pints and PVC materials). This work focussed on their conversion in water and soil. This should provide an insight into their presence in the environment and an understanding of their degradation in the environment. A method for full speciation and determination of alkyl lead and inorganic lead (II) after the tetramethyllead degradation in aqueous samples has been developed. This was accomplished by in situ derivatisation with sodium tetraphenyllead borate NaB(Ph)4 derivative. The derivatisation was carried out directly in the aqueous sample and the derivatives were extracted using the supported liquid membrane probe extraction (SLMPE). The extracted analytes were then transferred to a GC/MS for separation and detection. This study focused on the transformation of tetramethyllead in aqueous media, at different concentration of major elements, K+,Na+,Ca++, Mg++,Cl-,SO4 --. Adsorption / desorption on soil of ionic organolead and organotin were also studied. As South Africa is one of the world’s major producers of coal, mercury should be monitored as it is a side product in coal combustion. The trend of inorganic mercury and methylmercury in sediment found in this work indicated a possible methylation of inorganic mercury to methylmercury in Klipriver sediments.

Environmental contamination has become a significant threat to the health and well-being of mankind as well as to the environment, prompting the establishment and implementation of stringent environmental regulations. The ability to accurately detect and quantify contaminants, such as mercury (Hg), uranium (U), and volatile organic compounds (VOCs), in real-time, in situ is of significant importance to monitoring and remediation efforts. In an effort to develop a real-time, fast-response detector that is portable, highly sensitive, and cost efficient, this research explored the feasibility of utilizing cavity ringdown spectroscopy (CRDS) in conjunction with various plasma sources and vacuum cavities to accurately detect trace quantities of contaminants. The feasibility of detecting Hg with a low power, low temperature candle-shaped microwave-induced plasma (MIP) and a copper surfatron microwave cavity with various plasma discharge tube configurations in conjunction with cavity ringdown spectroscopy (MIP-CRDS) is discussed. Detection limits were on the order of 221 ppt Hg in the vapor phase for the candle-shaped MIP and improved by a factor of 10 with the tube-shaped plasma. The ability to detect elemental Hg naturally-evaporating from contaminated soils and solutions was evaluated, and 10’s of ppt were consistently obtained. Additionally, the fine structure of the Hg 253.65 nm transition was observed with each iteration of this approach. The potential of effectively generating uranium atoms and ions with a low-power, lowlow rate microwave-induced plasma was evaluated. Uranium emission spectra covering 320 – 430 nm were obtained, labeled, and compared to the available literature values. Calibration curves were generated, and the detection limits were determined to be ~0.4 ppm. The feasibility of measuring U incorporating diode laser-plasma-CRDS was explored. The preliminary studies clearly show the ability to detect U vapor with this technique and sub-ppm detection limits were obtained. A continuous wave cavity ringdown spectroscopy system (CW-CRDS) incorporating commercially available telecommunications diode lasers was constructed, and the overall sensitivity of this system was evaluated by utilizing the absorption of the asymmetric C-H stretch overtones of several VOCs, including benzene, chlorobenzene, 1,2-dichlorobenzene, toluene, and acetone. Detection limits are determined to be in the ppb’s for each of the organics examined.