Manual and automatic solvent extraction techniques were used to concentrate organic material from natural waters. Field and laboratory extractions were compared to determine the most probable method and best solvents for efficient concentration of organic material from estuarine and sea waters. The large scale extraction processes utilizing extractors made from 55 gallon drums were operated both by manually moving perforated metal discs through the water and solvent for mixing and by bubbling air through the aqueous-solvent mixture. Resulting samples proved large enough for the detection of short-chain fatty acids (carbon length 1 through 10). Identification of organic constituents was by gas chromatography-mass spectroscopy. Other portions of these samples were separated by column chromatography with subsequent analysis by infrared, visible, ultraviolet, and mass spectroscopy. The proximity of the Hanford Atomic Product Operations to the collecting area caused some of the organics to be labeled with trace amounts of radionuclides. A counter-current pulse column extractor was used at sea aboard the Research Vessel YAQUINA. The organic solvent, hexone, used in this extraction was distilled before and after the extraction with various fractions of solvent being kept for control. The extraction was carried out under varying chemical and physical conditions. The hexone was back-extracted into hydrochloric acid, sodium bicarbonate, or sodium hydroxide before analysis by flame-ionization gas chromatography and mass spectroscopy. Other portions of the product hexone were analyzed for total solid matter recovered and carbon, hydrogen, and nitrogen content. Small intermediate scale extractions were carried out in the laboratory using several solvents. Resulting organic material was analyzed by tandem gas chromatography-mass spectroscopy. Where possible, organic derivatives were prepared to aid in the identification of the recovered organic material. The advantages and disadvantages of large scale extractions and small laboratory procedures were discussed. / Graduation date: 1967

Graduation date: 1966

Graduation date: 1971

Graduation date: 1974

A two-dimensional finite difference model is developed for the simulation of saltwater intrusion in wave-induced aquifer system with either a confined or phreatic aquifer. The model considers many important factors, such as the dynamic pressure induced by wave motion, the pressure wave equation, the density-dependent Darcy¡¦s Law, and the salt transport equation. This paper presents numerical study of the effect of wave motion, resulting salinity structure responses and phreatic surface fluctuation on the process of seawater intrusion ¡K etc.

Thesis (Ph. D.)--School of Earth and Atmospheric Sciences, Georgia Institute of Technology, 2004. Directed by William L. Chameides. / Vita. Includes bibliographical references (leaves 144-162).

Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (p. 148-154).

This thesis describes the design, optimisation and shipboard deployment of a flow injection - chemiluminescence (FI-CL) technique for the determination of cobalt (Co) and manganese (Mn) in seawater. Chapter One presents an overview of the marine environment and the biogeochemistry of Co and Mn. Current analytical methods for the determination of Co and Mn in natural waters are also reviewed. Chapter Two reports reagent clean-up techniques and the synthesis of an 8- hydroxyquinoline resin used for in-line matrix elimination and preconcentration. The resin is also characterised in terms of its chelating ability for the transition metals and the earth alkaline metals. A new column design is also presented. Chapter Three details the optimisation of a FI-CL system for the determination of Co in seawater. The method described is based on a new chemistry whereby CL emission is produced by oxidation of pyrogallol with hydrogen peroxide in alkaline medium in the presence of CTAB and MeOH. Chapter Four details the optimisation of a FI-CL system for the determination of Mn in seawater. The method chosen involved the luminous oxidation of 7,7,8,8- tetracyanoquinodimethane (TCNQ) by dissolved O2. The weak chemiluminescence of TCNQ is effectively sensitised by Eosin Y in DDAB. In Chapter Five the application of the FI-CL method to the shipboard determination of Co in the western North Sea is presented together with results from the determination of Mn in the western North Sea samples after the cruise. Co and Mn profiles are shown for all the geographical area investigated. The data from an entire tidal cycle of the Humber are also shown. Chapter Six presents the results of an intercomparison exercise. Co and Mn have been measured with different analytical techniques: FI-CL, AdCSV, and ICP-MS. The method developed for Co has been adapted in order to measure the concentration of Co in samples from the Scheldt estuary with an integrated luminometer at the Universite Libre de Bruxelles.

No description available.

Results are reported from a series of experiments to determine the effects of certain environmental factors, namely, sunlight, temperature and , salinity on the survival of selected enteric bacteria which are of public health importance either as indicators of faecal pollution or The survival of the as pathogens. starved organisms in seawater and in freshwater microcosms exposed to artificial and natural sunlight, and in the dark, at a range of temperatures was investigated. An acridine orange direct viable count (AODVC) using an epifluorescent microscope was employed in addition to selective and non-selective cultural methods for estimation of decay rates of the test bacteria. The use of the AODVC allowed enumeration of those bacteria which respond to the stresses of the natural environment by entering into a viable but non-culturable form. These otherwise would not be detected, as they are, by definition, non-culturable using traditional enumeration techniques based upon the production of visible signs of growth. Two strategies were employed by the organisms in response to the unfavourable conditions. Prior growth of those members of the Enterobacteriaceae in a nutrient-poor medium before inoculation into the microcosms allowed adaptation of the cells to low nutrient concentrations, thus extending survival and resulting in higher resistance to other stresses such as visible light. This extension was, however, only temporary, the ultimate fate of the bacteria being death. Enterococci were particularly sensitive to low nutrient concentrations and died very rapidly in the light. All bacteria tested were able to adopt the viable but non-culturable strategy in the dark as a temporary measure, though it was only a matter of time before viability as well as culturability was also lost. This included enterococci, for which an AODVC using the antibiotic ciprofloxacin was developed by modifying the original nalidixic acid method. Responses of bacteria in the dark were influenced by temperature. Bright natural sunlight produced rapid death in bacteria exposed in seawater microcosms, a result of the synergistic interaction of salinity, UV light and possibly temperature too, whereas the presence of humic acids in freshwater afforded some protection to the cells by absorbing the damaging UV component of sunlight. Low intensities of UV and visible light typical of those found below the surface of water may induce bacteria to evolve towards a viable but non-culturable form.