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Atmospheric aerosol samples from coastal and open ocean environments in the North Atlantic were analysed for the atmophile elements arsenic and antimony, and for the marine tracers sodium and magnesium. The aerosol concentrations of sodium and magnesium were similar in both environments, about 2000 ng Na (SCM)ˉ¹ and 320 ng Mg (SCM)ˉ¹. The atmophiles were more concentrated in the coastal aerosol, 0.67 ng As(SCM)ˉ¹ and 0.32 ng Sb (SCM)ˉ¹, than in the open ocean aerosol, 0.07 ng As (SCM)ˉ¹ and 0.086 ng Sb (SCM)ˉ¹, and as continental particles were only observed in the coastal aerosol, this indicates that arsenic and antimony in the marine aerosol are of continental origin. Total deposition fluxes to the North Atlantic were about 1.4 kt yrˉ¹for arsenic and antimony, and about 12 t As yrˉ¹ and 5 t Sb yrˉ¹to the dissolved phase of the English Channel. Coastal deposition was higher than the dissolved element fluxes from the River Tamar. From the above data, steady state models of the arsenic cycle were developed, and an anthropogenic perturbation rate was calibrated for kinetic analysis, to define the most sensitive areas of the geochemical cycle. Air-sea exchange exerts a major control on the atmospheric transport of pollutant arsenic to the sea, variations in river flow exert a minor influence. The major unknown factor in the biogeochemistry of arsenic is the size of the reservoir for low temperature anthropogenic mobilisation, as this has a larger long term effect than industrial pollutant input. Low temperature mobilisation may lead to a serious increase in the atmospheric arsenic burden. The modelling technique was extended to quantify a novel tentative model for antimony, which was subject to limited examination by kinetic analysis. Again, air-sea exchange exerts a major influence on the atmospheric transport of pollutant antimony to the oceans, although river flow exerts a larger influence than for arsenic. Low temperature mobilisation may be even more significant for antimony than for arsenic.

Most methods for the determination of trace elements in organic matter require the sample to be brought into solution, which may be achieved by heating with strong oxidising agents such as concentrated mineral acids, to decompose the organic matrix sufficiently to render the sample soluble, whilst not necessarily achieving complete decomposition. The use of microwave heating for this purpose, using sealed vessels under pressure, was investigated for a variety of food samples. One drawback of this otherwise rapid method is the time taken to cool the vessels before opening. The use of liquid nitrogen to cool the vessel walls - before, during and after the heating cycle - was investigated, and its effect on the progress of the digestion was assessed. Another problem is the control of internal pressure, which can rise very rapidly when digesting samples of high organic content, and ways of controlling excess pressure when digesting larger samples were devised. These included the use of an open pre-digestion under reflux using a microwavetransparent coolant liquid, and the use of vessels capable of withstanding higher pressures. The latter proved more convenient as they enabled complete dissolution to be achieved in a single stage without pre-digestion, although cooling of these vessels was much slower than for the low pressure vessels, so overall sample preparation time was similar. Various methods were developed for the complete dissolution of the samples using nitric acid and hydrogen peroxide. The degree of decomposition achieved for the different methods and sample types was monitored by measurement of residual carbon in the digests. A few samples were virtually completely decomposed with nitric acid alone, while the use of hydrogen peroxide, following a nitric acid digestion, was found to reduce residual carbon substantially in the others. The undecomposed material was analysed by various methods including ultraviolet/visible spectrometry, infrared spectrometry and thin layer chromatography. Decomposition products were found to include carboxylic acids, oxalates, phosphates, nitrates and nitro-aromatics. Complete decomposition of milk powder, which proved most resistant to oxidation, was achieved by further treatment with perchloric acid. This was found necessary for anodic stripping voltammetric analysis, which required the destruction of interfering organic species for accurate determination of trace elements, unlike other techniques such as inductively coupled plasma-mass spectrometry, where complete decomposition was not required.

The aim of this study was to. examine the relationship between organic maturity and trace element geochemistry of organic rich mudstones, to assess their behaviour as sources or sinks of metals during diagenesis, and their role in mineral deposit genesis. The suite studied consisted of 193 samples from the Draupne, Heather, and Kimmeridge Clay Formations from the Norwegian North Sea and onshore UK. All three formations had above average contents of C and S, and the Draupne and Heather Formations had a low carbonate content. The Draupne Formation was particularly enriched in a number of trace elements but only Cr, Mo, Nb, and U were enriched in all three formations. After transformation of the data to avoid difficulties in interpretation, correlation analysis allowed the trace elements to be divided into three groups on the basis of their mineralogical residences. The use of a battery of geochemical and mineralogical indices demonstrated that variation in sedimentological and environmental factors were significant within the formations studied, and that the relationship between organic maturity and trace element content could not be investigated in isolation. The technique of path analysis was used to assess the strength and nature of this relationship relative to the variation due to other causes. Pb and Zn were found to increase with increasing maturity in both the Draupne and Heather Formations, and Mo was found to decrease. U was seen to decrease, and Cd to increase, in the Draupne Formation only, where they were especially abundant. It is believed that Pb and Zn were supplied by migrating basinal brines which may have acted to remove Mo and U. Other processes which may have mobilised these elements are the in situ generation of organic acids and hydrocarbons.

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Typescript. / Thesis (Ph. D.)--University of Hawaii, 1967. / Bibliography: leaves 118-123. / vii, 123 l graphs, tables