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Passive sampling, as opposed to the conventional spot or bottle water sampling technique, has shown to be reliable and efficient in monitoring the toxicologically relevant, freely dissolved (e.g. bioavaialable) concentrations of a wide range of organic contaminants in water. At the same time, partitioning controlled delivery (passive dosing; PD) techniques promise to overcome many of the challenges associated with toxicity testing of hydrophobic substances that may bias the interpretation of toxicity data. The present study investigated the feasibility of coupling silicone rubber passive sampling devices (SR-PSDs) with bioassay techniques for both chemical and ecotoxicological assessment of complex mixtures of organic contaminants in the aquatic environment. SR-PSDs were deployed in water at various locations within the Ythan catchment (north east, Scotland, UK), Forth estuary and the Firth of Forth (east coast of central Scotland, UK) for 7 to 9 weeks. Following retrieval, extracts from the SR-PSDs were analysed for dissolved concentrations of a variety of organic contaminants including PAHs and PCBs using GC-MS and GC-ECD respectively and were screened for a wide range of pesticides using GC-MS/MS and LC-MS/MS. The extracts were further evaluated for acute cytotoxicity (i.e. neutral red uptake assay) and EROD induction potential using rainbow trout liver cell line (Oncorhynchus mykiss; RTL-W1) and for phytotoxicity and developmental toxicity potential using algal growth inhibition test (with a marine phytoplankton, Diacronema lutheri) and fish embryo toxicity test (with embryos from zebrafish Danio rerio) respectively. Overall, the individual and total dissolved concentrations of PAHs (ΣPAH40; parent and branched) and PCBs (ΣPCB32; ortho and mono-ortho) measured in water from the Ythan, Forth estuary and Firth of Forth were relatively low compared with other studies using PSDs. A number and level of pesticides, including insecticides, herbicides and fungicides of varying hydrophobicity (log KOWs ~2.25 to ~5.31) were detected in the silicone rubber (SR) extracts from the Ythan catchment, the Forth estuary and the Firth of Forth, suggesting input mainly from agricultural run-off and possibly from direct discharges. No statistically significant (p<0.05) acute cytotoxicity was observed following 48 h exposure of RTL-W1 cells to SR extracts from the Ythan catchment. But, on a sublethal level, for every site, statistically significant EROD activity was observed to some degree following 72 h exposure. In addition, developmental and algal toxicities on embryos of D. rerio and D. lutheri respectively, were measured in all the deployed samples compared with the procedural controls (undeployed samples). Interestingly, extracts of SR-PSDs from the Forth estuary and the Firth of Forth exhibited growth inhibitions on D. lutheri that were similar to those of extracts from the Ythan, even though, fewer numbers of pesticides were detected in the Forth estuary and Firth of Forth than the Ythan. This suggests that pesticides were not solely responsible for the observed effects in the Ythan catchment. To further improve data from toxicity testing of hydrophobic substances, the study identified the use of SR O-rings as a suitable passive dosing format in in vitro toxicity tests and was partially validated through their use in dosing RTL-W1 cells with two individual PAHs and subsequently determining cytotoxicity and EROD-activity.

Marine pollution resulting from oil spillage has received much attention mostly due to the damaging effects it has on fisheries and aquacultures. One component of oil that is widely studied due to its toxic and carcinogenic properties is the polycyclic aromatic hydrocarbons. The physical and chemical properties of these compounds control their distribution into the various phases of the environment. The rates of elimination of these compounds from impacted organisms were investigated in laboratory and field experiments using selected marine organisms (Mytilus edulis and Salmo salar). The elimination of individual PAH compounds followed first order kinetics. Elimination rate varied among compounds and generally decreased with increase in molecular weight and degree of alkylation. Elimination rate constants (k2) and biological half-lives (t1/2) evaluated from chronically exposed mussels (collected from Aberdeen harbour) in separate laboratory and field studies were comparable but differed from those evaluated from acutely exposed mussels. Shorter t1/2 were obtained from acutely exposed mussels. The t1/2 ranged between 0.5- 22 d (acute exposure) and 3.8- 31.5 d (chronic exposure).The longer apparent t1/2 calculated for the chronically impacted mussels was attributed to the retention of the compounds in a stable compartment due to long period of exposure that limited exchange with the surrounding water. Contrary to expectation, t1/2 for similar compounds was higher in salmon than in mussels. The reason for this was unknown but attributed to the route of elimination. A good correlation (r2 > 0.72) was found between PAHs tissue concentration and taint intensity in salmon. Comparison of the results from this study with literature data showed that tank water replacement time and exposure duration affects rate of PAHs elimination. The data generated in this study and some of the reviewed studies will find application in different oil spill scenarios. The usefulness and limitations of the n-alkanes profile, PAH distribution and concentration ratios, and specific biomarker ratios from organisms in oil spill source identification was also demonstrated.

This thesis investigates and develops a stratified random sampling design for sediments in an offshore oil field environment. The sampling area was partitioned equally into 16 Zones, stratification were based on the near field and far field areas, and the number of samples in each Zone was chosen by proportional allocation, i. e. proportional to the available appropriate area (far field). Measurement techniques applied to the samples included laser granulometry, ultraviolet fluorescence, gas chromatography using mass selective detection or flame ionisation detection and elemental analysis. The total PAH concentrations (2- to 6-ring parent and alkylated PAHs, including the 16 US EPA PAHs) in sediments were relatively low (< 100 pg kg" dry weight). The PAH concentrations, Forties crude oil equivalent and diesel oil equivalent concentrations were generally higher in sediment of fine grain size and higher organic carbon loading. PAH distributions and concentration ratios Indicated a predominantly pyrolytic input, being dominated by the heavier, more persistent, 5- and 6-ring compounds, and with a high proportion of parent PAHs. The nalkane profiles of a number of the sediments contained small, high boiling, UCMs, indicative of weathered oil arising from a limited petrogenic input. Spatial structure analysis shows the existence of a trend in the variogram, and also the spatial pattern in the contour maps of the parameters measured, shows that the regionalized variable exhibited non-stationarity and were non-ergodic. The stratified random sampling scheme showed significant advantages over a classical grid sampling scheme when applied to the same area. Specifically, the stratified random sampling design gave much more reliable mean concentrations for all the parameters, achieving a much lower variance than the grid sampling. A further composite random sampling scheme was designed for sediments in the near-shore. The aim is to estimate a within-stratum mean value for each of the chosen measurement parameters with more thorough coverage (better representation), better precision and less variance at lower analytical cost. This scheme was trialed in two near-shore environments, the Clyde Estuary and the Firth of Forth. The results show no significant differences between the mean and distribution profile of the individual samples and the composite samples for all the parameters measured. This work utilised the best modern chemical analytical methods for the quantification of a range of hydrocarbon species, and utilised the results in a modem risk-based approach to environmental assessment. The new stratified random sampling design has been accepted for use in the national marine monitoring programme (NMMP) In the United Kingdom.