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The high particulate association of PAH in aquatic systems has often been attributed to the hydrophobic nature of the compounds leading to adsorption. Results presented i n this thesis strongly suggest that a significant proportion of PAH in the Tamar are particle-incorporated and unavailable for dynamic partition and physical, chemical and biological fates. The generally uniform PAH composition identified throughout the estuary is highly indicative of a combustion or road and urban runoff source. PAH distrubution in a dated Tamar Estuary sediment core showed an exponential decrease with depth and identified dramatic increases in PAH flux during the last 20 years. This suggests an association with motor vehicles probably via road runoff. No significant trends of change in PAH composition with depth were apparent, indicating unifoinnlty of source and the unimportance of PAH degradation mechanisms in the anoxic-sediment. Ibrylene displayed an anomalous distribution that could be attributed to its biogenic origin. A survey of PAH distribution in the estuarine water column identified two areas exhibiting high concentrations. The first was observed at the turbidity maximum at the head of the estuary (by virtue of particle-associated PAH) and the second as a result of an emission in the urban region during the, sampling period. A similar distribution was identified in the estuarine surface sediments which are shown to act as a sink for both riverine and urban PAH. Suspended particulates in the water column, in general, contain similar levels and compositionally reflect the higher molecular weight PAH (M>200) in the sediments. Ihis underlines the importance of particulate transport and indicates that degradation of these PAH in the water column, is of minor significance, with sediment incorporation as their primary fate. Lower MW PAH (MW<200)were enriched in soluble forms in the water column. Microbial heterotrophic degradation and volatilisation are proposed as important environmental fates of these low MW compounds.

There is considerable variation in public opinion data on the environment.  While very general items suggest concern is strong, measures focusing on steps that might be taken to promote environment protection suggest weaker public commitment to green issues. Moreover, in open-ended most important problem polls - i.e. items that measure the relative important of different issues in the public mind - concern for the environment has barely registered at all over recent years.  Different poll and survey items also provide varying impressions regarding <i>trends</i> in environmental concern. Whereas some suggest this is one the increase, others indicate that it has fluctuated and still others that it is in decline.  This thesis seeks to develop an understanding of these paradoxical findings. While in the first instance it considers ways in which the survey instrument itself promotes variation, the central focus is on the nature and origins of environmental opinions. Contrary to dominant approaches to conceptualising environmentalism, including Inglehart’s Postmaterialist thesis, it is argued that concern for the environment is not a product of individual volition but rather is externally constructed by ‘environmental meaning producing institutions’, particularly interest group and the media. Only by seeing concern in this way, it is suggested, can we begin to understand the variation summarised above. The remainder of the study explores the significance of arguments presented for wider paradigmatic debates in political science. It suggests that the constructionist perspective advanced undermines key assumptions of rational choice theory - the pre-eminent theoretical perspective in the discipline. The thesis concludes by considering implications of arguments presented for the future of environmentalism. It also considers implications for the study of public opinion and for the related field of democratic theory. On the latter point, the key argument advanced is that the conception of the individual developed in the thesis raises doubts about current calls for more public involvement in political decision making and, in particular, the new and widespread interest in deliberative democracy.