Biomarker characterisation and hydrous pyrolysis of bitumens from Tertiary volcanics, queen Charlotte islands, British Columbia, Canada

A number of bitumen samples have been recovered from vugs and fractures in outcropping Tertiary basalts of the Queen Charlotte Islands off the west coast of British Columbia, Canada. n-Alkanes and acyclic isoprenoids are not present and the polycyclic biomarker distribution of the four samples analyzed by GC and GC-MS has been altered. One sample contains no remaining recognizable biomarkers. Two bitumens were also obtained from Lower Jurassic potential source rocks, including one from the Sandilands Formation, which was considered previously to be the most likely source of the Tertiary bitumens. Although these two bitumens were also taken from outcrops, they are considerably less biodegraded. The Sandilands Formation bitumen contains 28, 30-bisnorhopanes and since these compounds were not detected in the Tertiary bitumens, there is no evidence from the initial results for a Sandilands Formation contribution to the hydrocarbons in the Tertiary basalts. The presence of 18α(H)-oleanane in the saturate fraction of two of the Tertiary bitumens from widely separated locations indicates that they are at least partially sourced from Tertiary organic matter.Because the distribution of biomarkers in some samples has been severely affected by biodegradation, the asphaltenes of the bitumens were hydrously-pyrolysed and the saturate fractions of the resulting pyrolysates analysed for possible additional information on the origin of the bitumens. The pyrolysates from the more degraded samples contain compounds not detected in the saturate fractions of the original bitumen and show some of the expected characteristics of the original non-degraded bitumen. However, the compounds most useful for correlation are not present in the pyrolysates apparently due to their non-incorporation into the kerogen macromolecule. Our results suggest that hydrous-pyrolysis of asphaltenes is of limited use in the correlation of biodegraded samples and in determining their origins.     

NOAA gulf of Mexico status and trends program: Trace organic contaminant distribution in sediments and oysters

Polynuclear aromatic hydrocarbons (PAH), chlorinated pesticides, and polychlorinated biphenyls (PCB) concentrations were determined in sediment and oysters to provide information on the current status of the concentration of these contaminants in Gulf of Mexico coastal areas removed from point sources of input. Coprostanol analyses of sediments showed that anthropogenic materials are associated with the sediments at all 153 stations sampled. The levels of contaminants encountered are low compared with areas of known contamination. Average PAH concentrations are nearly the same in oysters and sediments, although the molecular weight distribution is different. Average DDT and PCB concentrations are higher by a factor of 10 to 130 in oysters as compared to sediments. Continued sampling and analyses will allow for long-term trends in the concentrations of these contaminants to be determined.     

Biological methods of prospecting for gold

Biological methods (geobotany, biogeochemistry and geozoology) of exploration for gold are reviewed. Data are also presented for the gold content of 134 species of plants. Methods of chemical analysis for gold are also reviewed. The section on geozoology includes a discussion of the use of termite hills in prospecting for gold in Central Africa.     

Biogeochemical prospecting for uranium in Nova Scotia

Ashed twigs of Picea rubens (red spruce) collected over an area of uranium mineralization in central Nova Scotia were analyzed for uranium in the course of biogeochemical prospecting for this element. Uranium levels in background samples were significantly lower than in those collected from areas with mineralization either at depth or on the surface. Scintillometric data were useful only to differentiate background and surface mineralization. Uranium levels in soils showed no correlation whatsoever with mineralization or with radiometry. There was a very high degree of correlation between the scintillometric data and uranium concentrations in ashed twigs and it is considered that twigs of Picea rubens might be successfully used for biogeochemical prospecting for uranium in this area.     

European species of Thlaspi L. (Cruciferae) as indicators of nickel and zinc

The analysis of herbarium specimens has shown that unusual metal uptake by European species of Thlaspi (Cruciferae, mustard family) is not confined to the well-known accumulation of zinc from calaminiferous soils. At least twelve species show unusual accumulation of nickel, to levels of 1000–30,000 μg/g (dry-mass basis), from serpentine or other nickel-rich substrates. In addition, accumulation of zinc to levels above 1000 μg/g in the dry mass of the plant is widespread; about three-quarters of the European species, from a wide variety of soil types, have been found to exhibit this behaviour in the natural state. These observations are significant in many fields, including taxonomy, plant physiology and phytochemistry, but are particularly important in extending the potential of biogeochemical methods of mineral exploration.     

Ocean storage of nuclear wastes? Experiences from the Russian Arctic

An international demonstration (RD&D) project for ocean storage of radioactive wastes should be proposed, to study the feasibility of the concept of ocean storage of nuclear waste. This international project should utilize the scientific, engineering and technical capabilities of selected universities, oceanographic institutions, NGOs and industries. This project would need to be an independent (non-governmental) study, utilizing the capabilities of selected universities, oceanographic institutions, environmental NGOs (Non-Governmental Organizations) and industries. Scientists and engineers first need to conduct an engineering, environmental, and economic feasibility study of the concept. The goal of the project would be to determine if ocean-based storage reduced the risks to the environment and public health to a greater degree than land-based storage. This would require comparing the risks and factors involved and making the data and information available to anyone, anywhere, anytime on the internet. The mere presence of an investigation of the ocean storage option could facilitate scientific and engineering competition between the two options, could subsequently reduce environmental and public risks and provide better protection and cost benefits in the system utilized. One of the primary concerns of the scientific community would be related to the sensitivity and precision of the monitoring of individaul containers on the ocean bottom. An advantage of the land-based option is that if there is a release, its presence could be detected at very low levels and be contained in the storage facility. On the ocean bottom, a release from a container might not be easily detected due to dispersion. Therefore the containment system would have to be a system within a system with monitoring between the two providing greater protection. Ocean storage may have greater technical and political hurdles than land-based options, but it may provide greater protection over time, because it negates the threat of terrorism, it therefore merit further study. In the future if the use of nuclear energy and nuclear wastes increases, the global society could benefit from this international project, because it could reduce environmental and public health risks and promote energy independence.     

Spatially discontinuous modern sedimentation in Georgian Bay, Huron Basin, Great Lakes

High-resolution seismic reflection profile data show that the modern sediment cover (over the last 150 years) in Georgian Bay is thin and spatially discontinuous. Sediments rich in ragweed pollen, largely derived from siltation linked to land clearing and European settlement, form a thin, discontinuous veneer on the lakebed. Much of the lakebed consists of exposed sediments deposited during the late glacial or early postglacial. Accumulation rates of modern sediments range from < 0 mm/year (net erosion) to ∼3.2 mm/year, often within a few hundred metres spatially. These rates are much lower than those reported for the main basin of Lake Huron and the other Great Lakes, and are attributed to the low sediment supply. Only a few small rivers flow into Georgian Bay, and most of the basin is surrounded by bedrock of Precambrian gneiss and granite to the east, and Silurian dolostone, limestone and shale to the west. Thick deposits of Pleistocene drift, found on the Georgian Bay shoreline only between Meaford and Port Severn, are the main sediment source for the entire basin at present. Holocene to modern sediments are even absent from some deep basins of Georgian Bay. These findings have implications for the ultimate fate of anthropogenic contaminants in Georgian Bay. While microfossil assemblages in the ragweed-rich sediments record increased eutrophication over the last 150 years, most pollutants generated in the Georgian Bay catchment are not accumulating on the lakebed and are probably exported from the Bay.