The distribution of trace metals (Fe, Mn, Cu, Cd and Pb) has been determined in dissolved and particulate phases, along with relevant hydrographic parameters, from the nearshore coastal zone of the western North Sea (between 52ON and 56ON) during four Land Ocean Interaction Study (LOIS) surveys covering the seasonal cycle (autumn 1994 to summer 1995) The behaviour of the redox-sensitive metals, Fep and Mnp in the western North Sea were strongly correlated (r>0 44 for all seasons, P<0 05) in all surveys and exhibited maximum concentrations in winter (16 mg g -1 and 700 ug g-1 respectively) which progressively decreased throughout the year Distinct seasonal variations were also observed for particulate Cu, Cd and Pb For example, enhanced concentrations of Cup (36 ± 39 ug g-1) and Cdp (0.36 ± 0.42 ug g -1) in the Humber coastal zone during summer were attributed to preferential particulate organic/biogenic-metal interactions. In contrast enhanced, though diffuse, atmospheric inputs of Pb from continental winds were considered to have contributed to the elevated Pbp concentrations (82 ± 27 ug g -1) observed offshore during winter Results from radiotracer incubation experiments suggest that biological activity makes a significant contribution to the removal of dissolved Mn and Cd to the particulate phase. However, a phase lag of two to three months between maximum primary productivity and maximum particulate metal adsorption (KD=2 X 104 & 5 x 102 for Mn and Cd respectively) indicates a decoupling from the spring plankton bloom In general metal distributions in the Humber coastal zone were significantly influenced by freshwater discharge, tidal regime at the mouth of the estuary and prevailing wind conditions Total trace metal fluxes across the mouth of the Humber Estuary were highest during spring (311, 8 96 & 1045 kg day-1, for Cu, Cd and Pb respectively) and lowest during summer (25 7, 1 .12 & 33 4 kg day-1, for Cu, Cd and Pb respectively) They were dominated by variations in freshwater outflow and the tidal range during sampling On an annual basis comparison to estuarine inputs (rivers, industry and sewage sources) suggested retention of Cu (25%) and Cd (56%) Estimates of partitioning (KD) were derived from the dissolved and particulate data for Cu, Cd and Pb over the seasonal cycle Copper was dominated by the particulate phase (73-80%) in all seasons but summer, whilst Cd showed particulate phase dominance (54-70%) in autumn and winter only The Pb distributions were dominated by the particulate phase (94-99%) independent of season Trace metal settling velocities implied that the Humber Plume was acting as a sink for Cu, Cd and Pb in winter and spring However settling velocities calculated for Cd and Pb (flood tide) in summer were similar to background suspended particulate matter (SPM) suggesting long range transport with the residual circulation. Modelling of Pb isotopic ratios in the Humber Plume suggested that on average 32-39% of the extracted Pbp originated from anthropogenic sources The data from this study has given unique information concerning the concurrent seasonal distributions of particulate trace metals in the western North Sea and have yielded new insights into mechanisms affecting trace metal cycling and transport, essential in the development and refinement of coupled hydrodynamic-geochemical models.

Studies of living benthonic foraminiferal assemblages carried out by marine biologists are comparatively rare. This study of the changes in foraminiferal assemblages from three subtidal sites near Plymouth, U.K., has been carried out with the intention of determining the importance of various abiotic and biotic variables to the foraminiferal communities studied using statistical correlation. Temperature and salinity at depth and particle size characteristics together with organic content, bacterial abundance and type, and other meiofauna present were assessed monthly with samples taken for foraminiferal content, and for seasonal diatom analysis. Deformed specimens were very rare in the examined samples of natural assemblages. Three different systems were used in an attempt to culture Elphidium crispiim (Linne) for ecotoxicological studies, which failed. Ecotoxicological studies were carried out upon Roialieila elaticam Pawlowski &amp; Lee and adult Ammonia batavits (Hofker). The types of deformation produced by laboratory-maintained Foraminiferida were found not to be specific to the stressor used and, therefore, the use of this group of Protozoa as indicators of specific pollution is not possible. The methods which Elphidium crispiim utilises to remain epifaunal were investigated and found to be primarily controlled by phototaxis, together with geotaxis.

Acquiring high quality in situ analytical data with good temporal resolution is required for developing models of phosphorus transport and biogeochemical behaviour. Chapter One describes the behaviour of phosphorus in the aquatic environment, its sources, its role in the eutrophication process and legislation to control its release into aquatic systems. It also summarises analytical techniques for the determination of phosphorus in natural waters. An examination of the hypothesis that the export coefficient modelling approach can be used to predict phosphorus loading in the River Frome catchment, Dorset on an armual and seasonal (monthly) basis is presented in Chapter Two. The model predicted an annual (1998) phosphorus load of 25,605 kg yr'\ compared with an observed (measured) value of 23,400 kg yr'V Monthly loads agreed well with monthly observed values except during months of variable discharge. Chapter Three describes a study on the comparison of sample storage protocols for the determination of total oxidised nitrogen (TON) and filterable reactive phosphorus (FRP) in the River Frome and Tamar Estuary. The results showed that optimum storage conditions were highly matrix dependent, with significant differences in measured FRP concentration over time between the River Frome and Tamar Estuary (due to different calcium concentrations) and between samples of different salinities (due to different bacterial populations). Chapter Four describes the development and deployment of a portable flow injection (FI) monitor for phosphorus determination in the River Frome. The automated monitor, incorporating solenoid micropumps and switching valves, a miniature CCD spectrometer, a graphical programming environment and a tangential flow filtration unit, achieved a detection limit of 0.67 pM and was able to monitor at high temporal resolution (every 30 min). Chapter Five examines historical water quality indicators and data fi-om recent shortterm, high temporal monitoring campaigns using the FI monitor in order to identify the key factors affecting phosphorus concentrations in the River Frome. Results showed the importance of catchment geology (chalk-based) and hydrological conditions in relation to other physico-chemical parameters in controlling phosphorus behaviour.

Members of the meiobenthos have been used extensively to determine the effects of anthropogenic perturbation in marine systems (Coull &amp; Chandler, 1992). Despite this, the meiofauna has been virtually excluded from freshwater pollution monitoring. This thesis aimed to address this research caveat, by evaluating the potential of stream meiofauna for monitoring metal-contamination. Meiofaunal communities were sampled from streams in SW England representing a gradient in metal contamination. Environmental variables in these streams were also measured to identify the important forcing agents structuring the stream benthos. Multivariate techniques demonstrated Cu, either alone or in combination with other environmental variables was of most importance in correlations with the composition of meiofaunal communities. Comparison with the macrofaunal data demonstrated that both components of the benthos responded in a similar way to metal contamination, although the meiofauna also highlighted other differences in water chemistry. The combination of meiofauna, macrofauna and temporary meiofauna in a combined metazoan community analysis gave the best discrimination of sites. Detection of metal-contamination was retained in meiofaunal data aggregated to the family level. The abundances of the harpacticoid copepod Bryocamptus zschokkei were consistently important in contributing to between-site differences in community structure. The harpacticoid, therefore was selected as an ecologically-relevant freshwater toxicity test for Cu. Laboratory experiments demonstrated that Cu had toxic effects on the survival and reproduction of Bryocamptus zschokkei. Although acute toxicity tests gave more rapid results, these effects on survival occurred at a higher Cu concentration than those in the chronic tests. Sub-lethal concentrations of Cu led to a reduction in the numbers of offspring per brood Animals with pre-exposure to chronic concentrations of Cu exhibited greater tolerance to this metal. In conclusion, more information may be gained by including the meiofauna, alongside the macrofauna, when monitoring the impact of contaminants on freshwater systems. To reduce the effort of processing samples it appears family level data could be used to detect metal-contamination. The novel use of B. zschokkei in laboratory tests, where it showed lethal and sub-lethal responses to Cu, demonstrated that this species may have much potential as an ecologically-relevant freshwater bioassay organism for this metal. The advantages of using meiofaunal species such as B. zschokkei as toxicity test organisms are discussed.

During the 1980s a decline in populations of the bivalve Scrobicularia plana was noted in several U.K. estuaries: tributyltin (TBT) was suspected of being the cause although its toxicity to adults could not be demonstrated except at elevated concentrations; disappearance of clam populations has been also observed in other European countries. Laboratory tests have revealed that: i) D-larvae hatching from embryos after 48 hours in TBT concentrations of 188 ngSn/l amounted to < 50% of control values, and doses of 364 ngSn/l or 20 µgCu/l prevented normal development in = 90% of embryos. ii) planktonic veliger larvae exposed for 10 days to nominal TBT doses ≥ 50 ngSn/l grew at rates which, at maximum, were one third of that exhibited by controls. iii) settling pediveligers subjected for 30 days to levels of TBT ≥70 ngSn/l suffered significant mortalities, and postlarvae kept at 23 ngSn/l displayed some shell growth which was both substantially reduced and grossly abnormal. iv) exposure for 30 days to 2! 300 ngSn/l or ≥20 µgCu/l impaired the burying activity in sand of small spat, and juveniles reared in TBT solutions at ≥ 28 ngSn/l grew significantly less than those in the control treatment. v) while small spat held in heavy metal polluted sediment suffered massive mortalities in 12 days, juveniles exposed for 36 days to butyltin contaminated sediment (0.4 µgSn/g) did not display any limited survival, but both their growth and burying activity were significantly reduced relative to those of juveniles kept in control sediments. It is concluded that in U.K. coastal areas where TBT in water during the summer-autumn months ranged from = 20 ngSn/l to = 200 ngSn/1 (i.e. = 50-500 ngTBT/l) and Scrobicularia plana populations disappeared or declined markedly, a cause-effect relationship is most likely to exist between the former and the latter through the deleterious effects of the chemical on the early life stages of the clam; in addition, the continued presence of sediment-bound TBT may render mudflats unsuitable for the development of larval and juvenile bivalves.

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&quot;^ 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 ^&quot;C analogues of the compounds under realistic estuarine gradient conditions (K^ range from 2.4 x 10** to 49.4 x 10&quot;* 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.