The effects of sublethal copper exposure at three levels of biological organisation were studied in the common shore crab Carcinus maenas (L.) (Crustacea, Decapoda). The three levels included the ultrastructure of respiratory and osmoregulatory gill tissues; ventilatory physiology (scaphognathite activity); and tissue metallothionein levels. Respiratory gill epithelia were more sensitive to sublethal copper exposure than osmoregulatory gill tissues. The cellular damage observed included severe epithelial necrosis and vacuolation, hyperplasia and haemocyte infiltration. In the respiratory gills, these changes were first present following exposure to 100 µg Cu Lˉ¹ At 500 µg Cu Lˉ¹, there was complete degeneration of the epithelia. In osmoregulatory gills, lipofuscin granules were formed at 300 µg Cu Lˉ¹. Signs of cellular damage (as observed in respiratory gills) appeared in the osmoregulatory gills only following exposure to 500 µg Cu Lˉ¹, and were restricted to areas proximal to the marginal canal. Copper concentrations below 100 µg Cu Lˉ¹ had no effect on gill tissues. This result is discussed with reference to previous studies, and related to inter-population differences and exposure techniques. Gill ultrastructural differences were observed in crabs from two estuaries with different levels of water-borne trace metals, and in crabs transplanted from the cleaner to the more polluted site. Differences included . varying densities of plasmalemmal folds and frequencies of cellular vacuolation, as well as composition and thickness of algal surface layers on the gill cuticle. Following laboratory copper exposures (500 µg Cu Lˉ¹), gill ultrastructural "damage" and tissue metallothionein levels were related to changes in scaphognathite activity. Physiological effects, including changes in scaphognathite rate and periods of apnoea, were exacerbated by increased temperature and hypoxia. Changes in scaphognathite activity and metallothionein levels were not consistent following several exposures to the same level of copper; results are discussed in relation to physiological influences. In contrast, gill ultrastructure showed consistent deterioration following exposure to 500 µg Cu Lˉ¹. Gill ultrastructure represents a reliable indicator of exposure to copper at this concentration compared to both scaphognathite activity and metallothionein concentrations.

Analytical techniques were developed for the detection of inorganic arsenic (As(III) and As(V)), monomethylarsenic (MMA) and dimethylarsenic (DMA) in water, pore waters, suspended particles and bed sediments of the Humber Estuary, Thames Estuary and the southern North Sea. Dissolved inorganic As in the Humber Estuary showed removal in the mouth of the estuary in association with an Fe-rich outfall. Intertidal sediments and suspended particles had elevated inorganic As concentrations in the vicinity of the As-rich outfall located in the low salinity zone. Particulate As had a distinct concentration gradient away from the estuary mouth, indicating the transport of As out of the estuary. The presence of MMA and DMA in the water column was attributed to the methylation of inorganic As by marine phytoplankton and was not detected when the seawater temperatures were below about 10° C DMA concentrations were higher than MMA. The Humber and the Thames Estuaries both had sources of inorganic As, but As methylation within the estuaries was not significant. MMA and DMA in the estuarine plumes and the North Sea showed strong seasonality, with concentrations below detection in winter, and maximum concentrations in late summer when the methylated As was 21% of the total As in the Humber and Thames Plumes. The concentrations of MMA and DMA in the early autumn (32% of the total dissolved As) were highest off the Dutch coast where the water temperatures were up to 18° C. There were no significant correlations between the methylated As and inorganic As, temperature, chlorophyll a nor phosphate. A water sample from a developing spring bloom was incubated and showed the removal of inorganic As at a rate of 0.04ugAs/l/day, but there was no subsequent increase in the dissolved organic species, indicating a delay interval between peak primary productivity and the release of MMA and DMA. Inorganic As was detected in the porewaters of the Humber and Thames Plumes. In late summer, MMA and DMA were found at equivalent concentrations in all the Humber Plume porewaters. Flux calculations indicated that the diffusion of inorganic As, MMA and DMA from the sediments into the water column was insignificant, largely as a result of low sediment porosity. However, a resuspension event caused a detectable increase in inorganic As at the bottom of the water column. The importance of this work to the development of the 3-D hydrodynamic model of the North Sea is discussed.

This thesis describes the use of in situ and laboratory techniques for monitoring of trace metals and master variables in the environment. Chapter 1 presents a general overview of trace metals, their sources, sinks and roles in estuaries and near coastal zones, their general characteristics and the importance of their behaviour in estuaries. Filtration and commonly used analytical methods for trace metals detemriinations in natural waters are also discussed. Chapter 2 highlights the importance of colloids (in the size range 0.2 to 0.4 \im) to membrane clogging and concludes that cojloids account for a significant part of clogging of membrane filters. The aim of this study was to extend earlier studies by examining the trends of filtrate concentrations as a function of filtration volume in riverine and estuarine waters with contrasting matrix composition, over two different seasons. Based on the findings presented in this chapter some metal specific filtration protocols are suggested. Chapter 3 provides an overview of developments in instrument automation that have led to miniaturisation and resulting in manufacture of portable electrochemical instrumentation. Such instrumentation has been used for continuous trace metal measurements from the banks of estuaries and on-board ships. The most recent developments in flow-through cells with a gelcoated Iridium (Ir) micro-electrode array have resulted in submersible in s/Yu voltammetric probes which allow long-term trace metal measurements at sub-nanomolar concentrations in coastal waters. Such In situ probes hold great promise for water quality monitoring. Chapter 4 presents the optimisation and validation of a Voltammetric In situ Profiling (VIP) system for the simultaneous determinations of Cd(ll), Cu(ll) and Pb(ll) in estuarine and coastal waters. The trace metal faction measured by the VIP system is termed 'dynamic' and includes and includes these free ions and small complexes with size smaller than a few nm. Systematic studies in NaNOa and seawater were conducted and these showed that variations in ionic strength, pH and dissolved oxygen did not affect the response of the instrument, whereas an Arrhenius type temperature response was observed. During the work, physical and voltammetric settings of the VIP system were considered and tested in detail in order to achieve the analytical requirements to perform measurements in the laboratory and during in situ deployments^ The VIP instrument has a detection limit (defined as 3cj) in seawater for Cd(II) of 23 pM, Cu(ll) 1.13 nM, and Pb(ll) 23 pM. The accuracy of the VIP system was determined with certified reference material (CRM), showing good agreement. Chapter 5 discusses the results of an international laboratory inter-comparison exercise, in order to verify precision and accuracy of measurements made by 4 laboratories that operate VIP systems located in Plymouth, U.K; Geneva, Switzeriand and Ancona, Italy, using laboratory reference methods as a comparison. Inter-comparison included analysis of Tamar Estuary samples and in situ VIP system measurements in the coastal waters of the Gullmar Fjord, Sweden. Chapter 6 presents the results of field deployment of the automated Voltammetric In situ Profiling (VIP) system for the simultaneous determinations of dynamic Cd(ll), Cu(ll) and Pb(ll) in three estuaries located in the Southwest of England, UK. The VIP instrument allowed the In situ determination of 2-4 samples h'\ In addition, the VIP system measured total filterable (0.4 pm pore size filter) concentrations of Gd(ll) and Pb(ll) in discrete estuarine water samples. Through a series of tidal surveys lasting 7-12 h each and totalling 7 surveys a high resolution data set including speciation information was built up that enabled an interpretation of geochemical processes in the studied estuaries. Chapter 7 shows the results of In situ determination of VIP dynamic metal concentrations in the Po plume arid Adriatic Sea. Concentrations were similar to those previously reported for this coastal sea system. The correlation of the metals with salinity was presented and highlighted the importance of local effluent inputs close to the river mouth for Cd(ll). The data demonstrated that the Adriatic was not heavily contaminated with trace metals. Chapter 8 presents the overall conclusions from the research and makes suggestions for future work.

The legal requirement to monitor discharges of harmful substances in industrial waste waters is presented in Chapter One, which also discusses the merits of using automated online analytical instruments for this purpose. Flow injection analysis with solid-state UV-visible detection is proposed as a potential on-line effluent monitoring technique, and the principles and advantages of this methodology are summarised. Chapter Two describes the development of a portable, automated Fl monitor for on-line determination of ammonia in liquid effluents. The development process culminates with deployments of the system at two chemical production sites, and validated results are presented for on-line analyses of real effluents. The principles of multivariate calibration of spectrophotometric data are summarised in Chapter Three, and five commonly applied techniques (DMA, SMLR, PCR, PLSl and PLS2) are described and compared. These multivariate calibration techniques are then applied in Chapter Four for the quantification of metal ions in model eflfluent systems, using diode-array spectral data sets. The relative predictive performances of the techniques are compared for both simple and more complex multicomponent systems.

In February 1997, the Governing Council of the United Nations Environment Programme initiated a protocol to reduce the risks to human health and the environment arising from persistent organic pollutants. The initial list of 12 families of organochlorine pollutants included polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) selected for their persistence, bioaccumulation capacity and toxicity. The aim of this work was to further understanding of the behaviour of these organochlorines (OCs) in estuarine systems. Field surveys were conducted at UK estuarine (Humber, Clyde and Dee) and coastal locations. Sediments were analysed for OCs and a range of chemical and physicochemical properties (trace metals, organic carbon content, specific surface area). Hydrographic measurements were also made to assist in defining the estuarine environment. Concentrations of PCDD/DF on a dry weight basis ranged from non-detectable (n.d.) to 11100 pg g"^ and PCB from n.d. to 3000 ng g Estuarine OC contamination was generally elevated above coastal waters concentrations. The distribution of OCs was studied to determine the extent of source, compound physicochemical, and particulate geochemical influences. In the Clyde estuary some source-related effects were observed but in the Humber estuary, characterised by highly dynamic conditions, these were masked by mixing of sediments. The characteristics of the sorbent were found to be of key importance with the content and nature of particulate organic carbon being the major control. To further understand the sorption behaviour of OCs, partitioning experiments were conducted with ^"C analogues of the compounds under realistic estuarine gradient conditions (K^ range from 2.4 x 10** to 49.4 x 10"* for TCB and 23.1 x 10Mo 313 x 10^ for TCDD). Particle concentration was found to be of key importance and it was concluded that this effect was transferable to environmental situations. Salinity was found to be a minor influence on partitioning behaviour. Development of sorption sub-models and their incorporation into an integrated estuarine contaminant transport model was demonstrated. A particle interaction-based sorption model was shown to only partially account for the observed partitioning behaviour; inclusion of an irreversibly adsorbed fraction may more adequately represent estuarine partitioning. Riverine and outfall discharges were simulated in the integrated contaminant transport model to demonstrate the influence of tidal hydrodynamics, sediment dynamics and variable partitioning applied to the Humber estuary.

The risk to groundwater quality following a sub-surface spillage of immiscible pollutants such as oil, petroleum and other organic chemicals is an increasingly potent threat, through escalating industrial application of such pollutants. This study significantly enhances the understanding of the flow of immiscible pollutants within soil, through field scale investigations to define the spatial variability and extent of a contaminated area and the development of a comprehensive framework for the analysis of oil pollutant migration. This study represents a first attempt by researchers to analyse oil pollutant migration on a wide range of scales, from pore- to field-level. The research shows that quantity of pollutant is a critical factor in determining the extent of oil migration. Permeability and porosity of the sample material are also important secondary factors. High permeability assists the migration of oil pollutants. Soils with a high porosity allow the pollutant to migrate vertically under the influence of gravity, whereas soils with low porosity induce lateral oil migration, as the oil spreads from the point of injection. A Jull scale field study using contrasting soil types determines that oil migration is approximately symmetrical about the point of injection. Experimental data is used to establish modelling capabilities for the characterisation of pollutant migration. Modelling is undertaken at two levels. The first consists of the development of simple Gaussian equations based upon observations of oil glomuses. The glomus approach, newly developed in this work, can be compared to a fractal model, with the glomuses observed in each of the different scales studied.

Uranium and thorium are the only elements in the actinide series which naturally occur in the environment in sufficient amounts for practical extraction. They are both radiotoxic and chemotoxic to humans due to the effects of the ionising radiation produced by their radioactive decay, the decay of their daughter products, and due to the chemical toxicity resulting from absorption into the body. Thus it is important to be able to quantitatively determine the levels of uranium and thorium in the environment. Measurement of low levels of uramum and thorium in the presence of high levels of inorganic and organic matrix components has been achieved by coupling on-line solid phase extraction (SPE) with inductively coupled plasma mass spectrometry (ICP-MS) detection. This allowed direct analysis of water samples without any sample pre-treatment offering detection Umits of 0.01 ng ml uranium and 0.006 ng ml thorium. However, in many studies not only do the total levels of uranium and thorium need to be determined, but also their speciation, since this can effect their toxicity and mobility in the environment. An on-line uranium speciation method has successfiilly been developed using a chelating resin micro-column attached to an ICP-MS. This method has been applied to the analysis.pf natural water samples (from Dartmoor, Devon, UK) and the results obtained indicate that the uranium-organic species such as those formed with humic substances are the major species present. A comparison of the pH and level of organic carbon (in a range of natural and synthetic water samples), with the level of uraniumorganic species indicates that the organic carbon concentration is a controlling factor in determining the level of uranium-organic species formed. The kinetics of dissociation of uranium and thorium-humic substance species was also studied. The slow rate of dissociation, observed indicates that once the uranium-humic species have formed these species could remain in the environment for some time. These studies also indicate that even if a change in environmental conditions affected the speciation,it would take time before the uranium and thorium-humic species dissociated and the system equilibrated to a new speciation profile. Two computer programs (WHAM and PHREEQCI) were used to model uranium and thorium speciation in aquatic systems. The Nuclear Energy Agency Thermocheraical Database Project (NEA-TDB) values were incorporated into both programs, as differences in the thermodynamic data provided with the two programs were found to have a major effect on the predicted speciation profiles produced by the two programs. Using the NEATDB values, both programs produced similar inorganic speciation profiles for a given aqueous system but when an organic carbon component was added to the system the two programs produced different predictions for the level of uranium-organic species. This reflected the different organic speciation components utilised within the two programs. WHAM uses a discreet site electrostatic humic substance model and PHREEQCI uses an analogy type model based on a 'model fulvic acid' dataset. A comparison of model predictions with experimental data for the same water sample, indicates that the WHAM program produces closer predictions to the experimental results than the PHREEQCI program. A fiirther study of the WHAM program, using synthetic water solutions with a range of pH, organic carbon and uranium concentrations, indicates that the program has a bias towards low predictions at high pH and low organic carbon concentrations (pH>7, organic carbon < 0.5 ug ml), but wil function satisfactorily within the range of conditions found in the natural (Dartmoor) water samples. The results of these studies should aid environmental investigation based on uranium and thorium where model predictions are to be used.

To further a quantitative understanding of the effects of weathering on oil spilled at sea, a series of laboratory experiments were conducted to investigate the dissolution and photodegradation kinetics of Kuwait crude oil in seawater. A simple and practical method was developed for the preparation of stable homogeneous samples of sea water-soluble oil (SWSF) at 25 "C. The dissolution was monitored by two independent but complementary methods; total dissolved oil was measured by a photochemical dissolved organic carbon (DOC) technique whilst the dominant soluble constituents, aromatic hydrocarbons, were measured by ultraviolet-fluorescence (UVF) spectrophotometry. Maximum dissolution was observed after slowly stirring oil on seawater for 5 days when concentrations were, respectively, 3.2-3.6 fig C mL * seawater (DOC) and 2.4 /xg diesel equivalents mL ' seawater (UVF). C^ntification of the photodegradation of individual SWSF constituents required development and optimisation of a more specific analytical method. The final method involved addition of deuterated internal standards, extraction with n-pentane, controlled evaporation (micro Kudema-Danish concentration) and gas chromatography-mass spectrometry (GC-MS). Particular care was taken to eliminate sample contamination and storage conditions were also optimised. The recovery of deuterated internal standards through the isolation steps ranged from 30% for benzene-d^ to 100% for phenanihrene-diQ. The method allowed more than fifty compounds, mainly low molecular weight aromatic hydrocarbons, to be identified and quantified in the SWSF. Alkylated benzenes ( Q ^ were the most abundant (98% of the dissolved oil) followed by alkylated naphthalenes (C0.3) (= 2%). The oil to seawater partition coefficient of individual hydrocarbons (K^^) showed that hydrocarbons of high aqueous solubility (e.g C0.2 alkylbenzenes) also possessed the lowest partition values, whereas compounds with high partition coefficients (e.g. alkylnaphthalenes) remained mainly in the oil phase. A reproducible method of simulating solar irradiation was established under controlled environmental conditions using a calibrated 1.8 kW xenon lamp. The photodegradation of a model SWSF compound (phenanthrene) followed first-order kinetics (kp= 0.317+0.029) with a half life (tj^J of 2.2 hr at 25 "^C when irradiated at 194 Wm'-. The extrapolation of to latitude 30 *'N (Florida summer sunlight) showed that phenantiirene would degrade in = 9 hr. Some photoproducts including fluorene, fluorenone, 2,2'-diformylbiphenyl, 2,3:4,5-dibenzoxepin, 3,4-benzocoumarin, and 9,10- phenanthrenequinone were identified by GC-MS, although these accounted for only 11% of the initial mass of phenanthrene. UVF and GC-MS methods for examining the photodegradation of phenanthrene were compared. The photochemical fate of the characterised SWSF was investigated using the optimised irradiation system. Benzene and C^s alkylated benzenes showed no evidence of photodegradation after periods of up to 48 hour under the lamp, however, some C4 alkylbenzenes (jec-butylbenzene, 1,2- dimethylbenzene, 1,2,4,5- + 1,2,3,4-tetramethylbenzene and 1,2,3,4-tetrametiiylbenzene) appeared to follow first-order kinetics with respect to irradiation time. The photodegradation rate constants (kp) of the alkylated benzene and alkylated naphthalene isomers were statistically different demonstrating that certain isomers will phoiodegrade faster tiian others under the same conditions. Half lives ranged from 11.8 to 33.6 hr at 25 ''C. The majority of naphthalene (i.e. C^^^) identified in the SWSF of Kuwait crude oil exhibited first-order photodegradation kinetics with differing rate constants. Half lives were: naphtiialene. 15.7 hr; 1-methyl and 2-methyl naphthalene, 14.9 and 12 hr, respectively; l-l-2-ethylnaphthalene, 15.9; 1,6-dimethylnaphthalene, 10.4hr; 1,3,7-and 1,2,4-trimethylnaphthalene, 11.95 and 12 hr, respectively. The low initial concentration of other naphthalene isomers did not allow for accurate photodegradation kinetics to be determined. Extrapolating the data to latitude 30 "N showed that die photodegradation ti;^ expected for tiie determined SWSF compounds were between 4.2 to 7 days. This would make photodegradation an effective weathering process for the removal of spilled oil, particularly in high solar radiation environments.

No description available.

An experimentally based study to investigate near infrared laser photoacoustic spectroscopy as a technique to measure oil pollution is described. Photoacoustic spectroscopy is shown to be well suited to the application of monitoring oil in water in a pipeline. The role of the physical parameters important to photoacoustic generation is shown to lead to an effective amplification of differences in the optical absorption coefficients for many hydrocarbons and alcohols in water. This amplification is typically an order of magnitude and persists at low concentrations of arialyte, such that a Nd:YAG source (2 mJ pulses) yields a 7.2 % increase in the photoacoustic signal magnitude for a 500 mg/I oil in water sample compared to distilled water, corresponding to a detection limit of 4 mg/I. Using a 904 nm diode laser as a source for photoacoustic generation, a detection limit of 400 mg/1 of oil is demonstrated. In addition there is found to be no discernible effect on the magnitude of the photoacoustic signal caused by the presence of optically scattering particles. The design and development of a photoacoustic instrument to measure oil in water is described, and the performance of such an instrument is compared to that of the competing technology.