Atomic spectrometric techniques such as ICP-MS offer exceptional sensitivity and multi-element capability for trace metal analysis but the formation of polyatomic ions (particularly below m/z = 80) can cause serious interferences. Such interfering species may be introduced via precursor atoms in atmospheric gases, the sample matrix or impurities in the reagents and gases. There is an environmental need to establish rapid multi-element methods of analysis for trace metals in environmental waters and the subsequent speciation of these trace elements. Natural waters, particularly those with a high dissolved solids content such as sea water are difficult to analyse directly by ICP techniques due to the sample matrix forming polyatomic ion interferences when using ICP-MS and matrix modification of the background when undertaking ICP-AES studies. This thesis describes the development of analytical methodologies involving on-line sample preconcentration and matrix removal for the determination of trace elements in natural waters and brines using ICP-MS and ICPAES detection for the determination of a suite of trace elements including cadmium, cobalt, copper, lead manganese, nickel, selenium and zinc. Chapter one summarises the techniques used for such analyses and a review of solid phases used for sample preconcentration and matrix removal is given. Chapter two describes the development of an on-line Fl-atomic spectrometric matrix elimination method for the determination of trace metals in the samples discussed. The method involved the chelation of the analytes onto a Metpac CC-1® IDA resin with the simultaneous removal of matrix ions, e.g. Na and CI. The method was successfully validated for the analysis of open ocean sea water and riverine water, and the application of FI-FAAS to the determination of Mn in riverwater using extended preconcentration times to improve sensitivity is described. The influence of sample matrix on the atomic emission of these trace analytes is also discussed. Chapter three describes the application of the developed method to the quantification of trace elements in produced water samples from the north sea oil and gas production fields. Results using FI-ICP-MS and FI-ICP-AES are compared, and a sample is digested using U.V. radiation in order to determine the amount of trace analytes bound to organic material. The influence of matrix concentration on analyte retention and column capacity is investigated, and data obtained from a series of breakthrough curves is used to predict the maximum breakthrough volumes of sample required before analyte is lost as the operating capacity of the column is exceeded, for samples of differing salinities. Chapter four describes the development of an in-situ method of preconcentration of a suite of trace elements using the column system described previously. In-situ preconcentration offers a number of advantages over traditional sample collection and preservation techniques and minimises the potential for sample contamination. The in-situ method involves the use of a battery powered preconcentration unit containing columns, reagents and suitable reagent and sample pumping facilities, and subsequent analysis of these samples in the laboratory by the use of FI-ICP-AES. The method is successfully validated using a coastal sea water certified reference material, and the method is applied to the determination of trace elements in a sample taken from the Tamar Estuary, Devon. Chapter five describes the development of an on-line FI preconcentration-HG-ICP-AES method for the speciation of inorganic selenium in water. Sample was preconcentrated on a Benson BA-XIO® exchange resin. On-line separation of Se(IV) and Se(VI) was achieved, and sensitivity was improved by the adoption of hydride generation prior to analysis for the determination of Se(IV). Se(VI) was determined after off-line pre-reduction to Se(IV). The method was tested by the determination of inorganic selenium in an SRM, NIST 1643C, Trace elements in water and results compared with previous work.

No description available.

No description available.

Complexities associated with dissolved organic matter (DOM) isolation from seawater have hampered compositional characterization of this key component of global carbon and nutrient cycles. Two techniques, Electrodialysis (ED) and Solid Phase Extraction (SPE), were combined to more effectively isolate DOM from salt-containing waters. Sample recovery was optimized and evaluated on a range of samples including coastal ocean seawater, open ocean seawater, artificial seawater from cultures of marine phytoplankton, and artificial seawater samples containing standard compounds of different molecular sizes and charge. ED was performed with a system optimized for processing 2 to 10 L sample volumes and SPE was performed using Bond Elut PPL exchange resin. With the combination of ED and PPL techniques an average recovery of 76.7 ± 2.6% was obtained for natural coastal seawater. Comparison of C/N ratios and fluorescence excitation emission matrices (EEMs) taken at the beginning and end of the recovery process indicated that the final recovered material was representative of the DOM present in the original samples.

No description available.

No description available.

The coastal township of Whangamata's reticulated water supply is provided by a number of groundwater bores, extracting water from local fractured rhyolite and andesite aquifers. A need has arisen to create a greater understanding of the aquifers, because of an increased demand for water abstraction. Water demand in Whangamata increases dramatically during the summer vacation period. Occupant numbers increase from 4,000 up to 50,000 during peak times, resulting in increased water demand. Over the past five years an increase in groundwater abstraction has produced an evident downward trend in bore water levels. Electrical conductivity is also increasing in several aquifers, posing a realistic threat of sea water intrusion and questioning the sustainability of current abstraction volumes. Multiple linear regression and an artificial neural network model were investigated as simple empirical forecasting tools for well drawdowns to predict the effect of future increases in groundwater demand. This approach was adopted as opposed to a groundwater numerical model because of poor time resolution of available data and the complex, fractured nature of the aquifer. By using pumping volumes as variables, seasonal bore water level variations and long term trends were predicted. The models were evaluated with independent validation data sets. The actual ability of a model to predict bore water level seasonal variation and long term trends was assessed using a comparison with a moving average of the validation data set. Multiple linear regression proved superior to the neural network in almost every bore modelled. Although neural networks proved capable of modelling seasonal bore water level variations it was not to the same degree of accuracy as the regression approach. The regression approach yielded a modified index of agreement of 0.6-0.74 when comparing a moving average of observed data with the validation data sets. The developed models were used to forecast well water levels with varying abstraction volumes aiming to prevent further long term decline in bore water levels.

Characterized as rich mineral substances, low temperature, few bacteria, and stability with numerous implementation aspects on aquaculture, food, drinking, and leisure, the development of deep sea water (DSW) has become a governmental policy and a new industry. The eastern region in Taiwan owns outstanding pumping DSW conditions and a prosperity on its industry applications is expected if the development project goes well. However, a design on the inspection mechanism is critical to the industry development due to water's indifference characteristics. This study aims at inspection problems relevant with certification mechanism to construct an overall certification operation system. An investigation is designed to understand the current inspection system status while implementation for the use of lab function requirements, inspection operation, and product inspection process considerations. A management conceptual mechanism is also provided for DSW industry development in the future

Diss. (sammanfattning) Göteborg : Göteborgs universistet, 2009. / Härtill 4 uppsatser.

Bacterial concentrations in natural sea water were significantly reduced by 5ptm filtration and subsequent treatment with ozone and UV light led to further reductions in total viable counts of bacteria and autoclaving water gave complete sterility. However, with the addition of artificial diets, such treated water was recolonised very rapidly and within 24h, these water samples had significantly higher bacteria counts than the 5pm filtered sea water treatment (f = 21.30; p<0.001). Further treatment of 5ýtrn filtered sea water also led to changes in the bacterial composition of the water. In ozonated and UV light irradiated water samples, the proportions of presumptive Vibrid sp. increased in the 24h following treatment while in 5ýLm filtered and natural sea water samples, the proportions of presumptive Vibrid sp. fell over the same period. When Penaeus indicus PZ1 stage larvae were reared to PI-1 stage in 5lam filtered sea water, good larval survival was obtained irrespective of whether live or microencapsulated artificial diets were fed. In contrast, larvae raised in autoclaved, ozonated and UV light irradiated water exhibited significantly lower survival when raised on live diets and often showed complete mortalities when fed on microencapsulated diets. In periods of poor sea water quality, additions of bacteria from algal cultures to PZ1 stage larvae fed algae had no effect on larval survival to M1 stage for larvae reared in 5gm filtered sea water or autoclaved water. In contrast, additions of these bacteria to larvae reared in 5pm filtered sea water and fed on MED, led to a significant increase in larval survival. This effect was absent when larvae were reared in autoclaved water. Addition of bacteria from algal cultures were found to inhibit counts of presumed viable Vibrid sp. while having no effects on total viable counts. No significant differences were observed in the percentage of soluble protein leached from microencapsulated diets and micro particulate diets when incubated up to 48h in bacterial laden and sterile water indicating that leaching is independent of microbial activity up to 48h. However broken microcapsules gave higher total viable bacterial counts over 48h in 5ýtm filtered sea water when compared with intact microcapsules. Significant levels of protection were conferred on larvae when either fresh or freeze-dried vaccines were administered by Immersion, but not when such vaccines were administered orally. The degree of protection offered was correlated with the virulence of the pathogen from which the vaccine was made. Enhanced protection given by vaccines produced from the more virulent strains was not wholly due to activation of the prophenoloxidase system since such vaccines induced less stimulation of the prophenoloxidase system than less virulent strains. Untreated plasma of Penaeus vannamei significantly enhanced Escherichia coli growth compared with sea water nutrient medium. In contrast, plasma from vaccinated prawns exhibited antibacterial activity detectable up to 7d after vaccination. Exposure to a mixture of fungicides Implicated in the initiation of the taura syndrome disease (TS), had no effects on the immune competence of P. indicus juveniles following live, in vivo pathogenic challenge. In addition, no effects on growth, growth rates, moulting rates or survival of postlarval and early juvenile prawns were observed following exposure to the fungicides. Prawns exhibited no gross or histopathological symptoms characteristic of TS.