Infrared study of the pyrolysis products of sporopollenin and lignite

The effect of pyrolysis at increasing temperature on sporopollenin, lignite and sporopollenin oxidized at 200°C has been investigated using measured infrared band absorption coefficients.Oxidation of sporopollenin in air at 200°C is marked by a decrease in the content of saturated hydrocarbon chains and a strong increase in the concentration of carboxylic acid groups.Pyrolysis of a thick bed of sporopollenin at increasing temperatures leads to the removal of a large proportion of oxygenated functions, before the removal of hydrocarbons. For lignite and oxidized sporopollenin, the loss of both types of functional groups extends over a broader temperature range. Reorganization of the carbonaceous residue at high temperature is hindered if a sufficiently low content of oxygenated functions, carbonyl and carboxyl as well as hydroxyl and ether groups, is not reached before the elimination of hydrocarbons.     

Lithium in tektites and natural glasses

Lithium concentrations in various tektites and natural glass samples have been determined using RNAA. For most tektites Li abundances range from 40 to 60 ppm, with the exception of bediasites (23 ppm). In other natural glasses of presumed impact origin, the Li values are considerably lower (6–11 ppm). It is suggested that the Li concentrations reflect mostly the original abundance of this element in parent materials. A terrestrial origin for tektites is supported by the Li range overlap between tektites and sedimentary rocks     

Monitoring trace elements in the mussel,Mytilus edulis using X-ray energy spectroscopy

X-ray energy spectroscopy has been successfully utilized to provide rapid, multi-elemental, quantitative analyses of the intertidal mussel, Mytilus edulis, found in southern coastal waters of British Columbia (Canada). Since no a priori decision needed to be made on which elements required monitoring, concentrations of the seven dominant elements (Mn, Fe, Cu, Zn, As, Se and Pb) were determined in the gills and viscera of these organisms. The potential usefulness of XES for providing relevant data on aquatic bioaccumulators for environmental monitoring studies is discussed.     

Thermal metamorphism of primitive meteorites—IX. On the mechanism of trace element loss from Allende heated up to 1400° C

We report data for Ag, Bi, Cd, Co, Cs, Ga, In, Se, Te, Tl and Zn determined by neutron activation in Allende samples heated for one week at 100° increments in the 1000–1400°C range in a low pressure (initially 10^?5atmH₂) environment using an apparatus of novel design. In the extremes, concentrations of these trace elements—initially present at ppm-ppb levels—in unheated material are lowered even farther by factors of 10^?4–10^?5 over a broad temperature span. Loss of some elements above 1000°C extends trends evident below 1000°C; loss of others is even more extreme. On Arrhenius diagrams some elements exhibit but one apparent activation energy over the entire temperature span of loss while others exhibit 2 or 3, each operative in a particular temperature region. These discontinuities seem related to mineralogic/petrologic alteration and probably reflect differences in diffusion mechanism rather than siting differences. The extension of previous experiments into the temperature regime postulated for chondritic differentiation should lead to a better understanding of the evolution of meteoritic parent bodies.     

Pelagic tar off Georgia and Florida in relation to physical processes

Following the Ixtoc I oil rig blowout in Campeche Bay we hypothesized that resulting tarballs should eventually appear in the Gulf Stream off Gerogia and that because of dynamic barriers in the innershelf little would reach nearshore areas. To test these hypotheses, surface tows to collect floating tar were taken off the coasts of Georgia and Florida in October and December, 1979.No tar was found within 40 km of the shore. All samples more than 40 km offshore contained some tar. The mean concentration was 0.82 mg m^?2 with a range of 0.01–5.6 mg m^?2. Closely spaced sampling showed extreme variation but trends were consistent. Perylene was the most abundant compound in the tarballs.     

Chlorinated hydrocarbons in gulls from the Baltic south coast

Polychlorinated terphenyls among organochlorine pesticides and polychlorinated biphenyls were detected in some gulls from the Gdańsk Bay, Baltic Sea.     

The influence of minerals on the pyrolysis of kerogens

The effect of mineral matter on the laboratory pyrolysis of sediments, kerogens and coals, and of coal macerals mixed with either alumina, bentonite, kaolinite, or calcium carbonate has been investigated. Some minerals are more active than others in effecting changes in the composition of the pyrolysate. The relative content of low molecular weight pyrolysis products is higher for kerogens pyrolyzed in a mineral matrix than for isolated kerogens. Our limited data suggests that this is due to both condensation and gasification of higher molecular weight constituents in the ‘primary’ pyrolysate. Differences in the content of aromatic versus aliphatic compounds have been noted when pyrograms from coal macerals are compared with pyrograms from coal maceral-mineral mixtures. We conclude that mineralogy is important in controlling the composition of kerogen pyrolysis products.     

1H NMR spectra of humic and fulvic acids and their peracetic oxidation products

¹H NMR spectra of humic (HA) and fulvic (FA) acids and their oxidative degradation products are reported. The HA shows the presence of -(CH₂)_n - CH₃ (n > 6) chemical fragments belonging to n-alkanes and/or n-fatty acids physically adsorbed onto the macromolecule structure. These fragments are absent in the FA fraction. Both humic fractions reveal the presence of similar amounts of aromatic protons which partly undergo exchange phenomena. The importance of this experimental observation is discussed. Oxidative degradation seems to cause partial cleavage of aromatic rings, more pronounced in the FA than in the HA. The degraded FA shows a higher total acidity and a higher phenolic OH content than the degraded HA. Both degraded fractions display some sharp singlet signals at 1.9 and 3.9 ppm arising from protons belonging to repetitive chemical fragments probably formed during the oxidation reaction. Tentative assignments of these signals are given. A general analysis of the HA and FA degraded spectra seems to indicate that the chemical fragments which undergo peracetic oxidation are substantially similar. The extent of oxidation of the two humic fractions is different. The HA degradation products reveal the presence of oligomeric structures, whereas the degraded FA appears less resistant to the oxidizing agent.     

Pyrolysis-high resolution gas chromatography and pyrolysis gas chromatography-mass spectrometry of kerogens and kerogen precursors

A series of kerogens and kerogen precursors isolated from DSDP samples, oil shales and Recent algal mats have been examined by Curie point pyrolysis-high resolution gas chromatography and gas chromatography-mass spectrometry. This study has shown that the three main types of kerogens (marine, terrestrial and mixtures of both) can be characterized using these techniques. The marine (algal) kerogens yield principally aliphatic products and the terrestrial kerogens yield more aromatic and phenolic products with some n-alkanes and n-alkenes. The yields of n-alkanes and n-alkenes increase and phenols decrease with increasing geologic age, however, pyrolysis-GC cannot be used to characterize the influence of short term diagenesis on the kerogen structure.     

Baseline levels of benzo(a)pyrene in southern California mussels

Marine mussels accumulate the carcinogen benzo(a)pyrene from contaminated environments. Baseline studies in California indicate that levels of the carcinogen in mussels are at or near zero, except in areas of human activity. This finding runs counter to previous suggestions that benzo(a)pyrene is widely distributed in marine organisms.