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Novel separation, extraction and detection methods were developed to accurately measure concentrations of perfluorinated compounds (PFCs) in environmental/food matrices. Sampling strategies and the significance of UK environmental PFC exposure were assessed by quantitative analysis of wildlife liver samples in aquatic and terrestrial food chains. As diet is the main exposure route for related contaminants, UK human PFC exposure was estimated through dietary studies. When analysing for PFCs in food, weak anion exchange solid phase extraction (WAX- SPE) is used for extract cleanup and liquid chromatography mass spectrometry (LC- MSIMS) for the quantification. This method was used to analyse the majority of foods in this PhD dietary study. Analysing fatty foods (cheese, meat, liver or eggs) is problematic, therefore fluorous biphasic systems (FBS) were investigated to partition PFCs from organic into fluorous solvents. When this developed FBS was prefixed to the conventional SPE method, PFC concentrations could be determined for the diet study by LC-MSIMS without enhancement/suppression from the fatty matrix. Aquatic and terrestrial wildlife livers were analysed by both conventional PFC methods and new techniques. PFCs were extracted using methanol, cleaned up by WAX-SPE and analysed by time-of-flight mass-spectrometry (LC-TOF-MS) or LC-MS/MS. The results showed two outcomes. Firstly, PFOS is readily detected in UK environmental samples, even from isolated ecosystems (Outer Hebrides) with very low anthropogenic contribution. Secondly, concentrations are of concern, as they are higher than those in foods of the UK diet. The mink would appear to be consuming food containing PFOS, thus indicating a contaminated environment. A database of PFCs «260) was developed, providing a valuable reference source. It contains molecular structures, compound names, abbreviations, formulae, fluorous percentages, neutral exact masses and the anion monoisotopic masses [M-Hr. The database is exportable and directly searchable by the LC-TOF-MS peak identification software and was used to screen environmental and food samples.

Cryptosporidium is a protozoan parasite causing cryptosporidiosis; a diarrheal disease of varying severity. The infection is transmitted by tiny spores called oocysts resistant to harsh environmental conditions and various disinfectants. Cryptosporidium infection and recovery from the illness is dependent on the body's immune system. It is important to be able to detect these parasites quickly to reduce the risk of infection. Multiple-angle light scattering systems have been developed for detecting cryptosporidium oocysts suspended in water. The proposed systems were set up with a single wavelength (red AlGaInP laser: 658.4 nm) and two wavelength (violet InGaN laser: 405.7 nm and red AlGalnP laser: 658.4 nm) sources. The single wavelength system was developed for measuring particle concentration and particle size and refractive index. It combined multiple-angle scattering detection, to collect angle- resolved scattered intensities from suspensions, and the partial least square regression method (PLS-R) to predict characterizing information of samples under investigation based on calibration models. The calibration models were composed from the calibration data generated from the experiments for particle concentration measurement and according to Mie theory with refraction and transmission corrections included for particles' size and refractive index measurements. The dual wavelength system was set up for particle identification by using relative wavelength scattered intensity as the identifying means. Measurement of particle concentration, size and refractive index by the single multiple angle light scattering system was validated using polystyrene spheres in aqueous suspensions. Applying the systems to cryptosporidium oocyst suspensions, the concentration measurement results had lowest errors from the references 9.5 % at concentration of 2.00x10600cysts/ml in mono-dispersion and 3.6 % at concentration of 7.50x105 oocysts/ml for cryptosporidium and mixed suspensions with polystyrene sphere suspensions. The measured cryptosporidium oocysts' size and refractive index were 4.37 ± 0.16!-Lm and 1.38 ± 0.05 which also had good agreement to the reference value (size: 4.38 ± 0.23 urn, refractive index: 1.37). The dual wavelength multiple-angle light scattering system collected the relative wavelength scattered intensities from suspensions of the cryptosporidium oocysts comparing to polystyrene spheres and E.coli. The relative wavelength multiple-angle scattered intensity of cryptosporidium oocysts suspension showed a characteristic scattering pattern and significantly different pattern from the polystyrene spheres and bacteria E.coli. The results presented in this research have demonstrated that the proposed multiple-angle light scattering systems have the capability to initially detect cryptosporidium oocysts in suspension. These systems could be further developed for online cryptosporidium detection by combination with pattern recognition techniques.

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Attenuated total reflection (ATR) of light in a SiO[2]/Si[3]N[4] planar waveguide was successfully exploited with a view to developing a highly sensitive enzyme sensor for monitoring typically agricultural and industrial water pollutants. The Si[3]N[4] surface of the waveguide sensing window was coated with nanocomposite polyelectrolyte selfassembled (PESA) membranes containing cyclotetrachromotropylene (CTCT) indicator and enzymes. The reaction of three enzymes namely urease, acetylcholine esterase or butyrylcholine esterase was accompanied by changes in pH, varying the absorption coefficient of the CTCT indicator. An experimental set-up of a single channel enzyme sensor was constructed to investigate the capability of the planar waveguide to register small changes in the light absorption of the PESA membrane. It was found that due to the multiple reflections phenomena, the sensitivity of a planar waveguide was higher than that for traditional absorption spectroscopy and previously reported waveguiding structures by at least three orders of magnitude. The respective enzyme reactions as well as their inhibition with toxic agents such as cadmium and lead ions were studied by in-situ monitoring the changes in output intensity of the planar waveguide. The results were remarkable, since traces of the above pollutants were detected with concentrations as low as to 1 ppb. The work was also extended to design and implement a laboratory scale enzyme sensor array. A multi-channel reaction cell and light guiding system were designed for this purpose. The analysis of the experimental results demonstrated that the multichannel enzyme sensor was able to produce adequate responses to the presence of different pollutants of industrial (cadmium, lead and nickel) and agricultural (imidacloprid, paraoxon and DVDP) origin, in the concentration range from 1 ppb to 1000 ppb. The distinct pattern of sensor responses was analysed by the implementation of artificial neural network algorithm. Despite a rather small amount of experimental data, the trained neural networks were able to classify and quantify the pollutants with an acceptable average error of 6.24 %.

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This study investigated the effects of various factors, namely exposure to brass/copper, sunlight, high temperature, chlorine, low pH, or starvation, on the enumeration of faecal indicator bacteria in water, performed using non-selective & selective media under conventional aerobic conditions & under conditions designed to neutralise reactive oxygen species e.g. by the addition of 0.05% w/v sodium pyruvate as a scavenger of peroxides &/or anaerobic incubation, to encourage fermentative metabolism. These methods were compared with standard US & UK methods for the recovery of injured bacteria. The information gained was used for the development of a novel broth-based medium for the enumeration of sub-lethally injured Escherichia coli under field conditions. The novel broth-based field medium ('Coliblack') was tested against a currently used method (H2S test) & evaluated under field conditions with unskilled personnel in rural locations in India. The results showed that growth conditions designed to neutralise reactive oxygen species could enhance the colony count of faecal indicator bacteria, whether enumerated using a non-selective medium, a selective medium, a resuscitative medium, or a chromogenic growth medium, following exposure to stressors such as storage of water in a brass container, sunlight, high temperature & chlorine. Such conditions may induce sub-lethal injury in E. coli & E. faecalis, inactivating the bacterial cells under conventional aerobic enumeration conditions as a result of their oxygen-sensitivity. However, exposure to some other stressors namely low pH & starvation was not strongly oxygen-sensitive, as no substantial differences between counts were observed on various growth media or enumeration conditions. The results from enumeration experiments were used to develop a field-based broth medium with a peroxide-neutralising resuscitative agent (sodium pyruvate), a selective agent showing minimum inhibition (Tergitol 7) & a chromogenic diagnostic agent based on defined substrate technology (8 hydroxyquinoline-glucuronide). The Coliblack medium indicates the presence of Escherichia coli in the drinking water by a colour change of the medium to black. Furthermore, the preliminary trial carried out for the evaluation of the novel broth-based field medium gave positive feedback from users. In this respect the results obtained in the present study represents an advancement in understanding of how to maximise the enumeration of faecal indicator bacteria in water & how to apply this information to improve detection under field conditions.