Nitrogen in tektites and natural glasses

Nitrogen concentrations in various tektites and natural glasses have been measured using RNAA and are found to be almost constant at about 15 ppm. A terrestrial origin for tektite formation is favoured.     

Non-cosmogenic lithium-6 in iron meteorites

A neutron activation method is used to measure⁶Li via the reaction⁶Li(n, α)³H in iron meteorites. It is found that most⁶Li occurs in non-metallic inclusions which can be separated by dissolution of the metal in 4 M H₂SO₄. The non-magnetic portion of such a residue has as high as 0.9 ppm⁶Li, while in the bulk sample⁶Li ranges from 0.02 to 10 ppb. Average⁶Li contents (ppb) for various classes are IA, 1.8; IIAB, 1.6; and IIIA, 0.4. Cosmic-ray-produced⁶Li is generally much smaller than the native⁶Li.     

Total nitrogen in iron meteorites

Total nitrogen contents have been measured by RNA of 30 iron and 4 stony-iron meteorites. Wide variations in N concentrations are noted (0.5 ppm to about 200 ppm). As a group, the IA irons have the highest nitrogen. This element is positively correlated with C, Ga, and Ge. Samples of meteorites that have been exposed to shock do not show any abnormal N distribution.     

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.     

Geochemistry of hydrothermal deposits from Loihi submarine volcano,Hawaii

Dredging across the northeast rim of the summit crater of Loihi Seamount recovered several morphologically similar but chemically and mineralogically distinct hydrothermal deposits encrusting the surface of fresh pillow lava talus. The multicolored deposits suggest a precipitation sequence that may be controlled by an oxidation-reduction gradient in which smectite ranging in composition from Fe-montmorillonite to nontronite has precipitated along with iron oxide under slightly reducing conditions. This deposition was apparently followed by amorphous iron oxide and silica precipitation, possibly under more oxic conditions. Oxygen isotope geothermometry indicates formation temperatures in the range of 31–57°C for the Loihi smectites. Trace element enrichments appear to be positively correlated with the isotopic formation temperature of the smectite, suggesting either increased trace element solubility within the higher-temperature vent fluids or increased smectite and iron oxide scavenging with increased precipitation rates. The trace element abundances further suggest the presence of polymetallic sulfides that either are directly associated with the smectites as amorphous phases or occur beneath these deposits in the volcanic pile of the seamount.     

Impact flows and crater scaling on the moon

The axisymmetric distribution of stress, internal energy and particle velocity resulting from the impact of an iron meteoroid with a gabbroic anorthosite lunar crust has been calculated for the regime in which shock-induced melting and vaporization takes place. Comparison of impact flow fields, with phase changes in silicates taken into account, with earlier results demonstrate that in the phase change case when the 15-km/s projectile has penetrated some two projectile radii into the moon, the peak stress in the flow is ～0.66 Mbar at a depth of 66 km, and the stress has decayed to ～66 kbar at a depth of 47 km. Rapid attenuation occurs because of the high rarefaction velocity of the high-pressure phases associated with a 35% (zero-pressure) density increase. This feature of the phase-change flow tends to strongly concentrate the maximum shock pressures along the meteoroid trajectory (axis) and makes the conical zone along which high internal energy deposition occurs, both shallow and narrow. Examination of the gravitational energies required to excavate larger craters on the moon indicates the importance of gravity forces acting during the excavation of craters having radii in the range greater than ～2 – ～140 km. It is observed that the “hydrodynamic” energy vs. crater radius relation approaches those for various “gravitational” energy vs. radius relations at the radii values corresponding to the larger mare basins. Cratering energy values in the range of (1.0 – 9.4) · 10³² erg are inferred on this basis for the Imbrium crater. Using these values and the criteria that all rocks exposed to ～100 kbar or greater shock pressures are included in the ejecta (some of which falls back) implies that the maximum depth of sampling expected to be represented within the Apollo collection lies in the range 148–328 km.     

Effect of enstatite activity and oxygen partial pressure on the point-defect chemistry of olivine

The variation of the point-defect concentrations in olivine with changes in enstatite activity and oxygen partial pressure are derived from formal thermodynamic arguments. Two models for these variations are constructed; the models differ in the choice of the approximate charge-neutrality condition in the near-stoichiometric regime. Under favorable circumstances, the effect of the oxygen partial pressure on olivine's point-defect chemistry can provide a diagnostic technique. Activity differences within the upper mantle may have a significant effect on olivine's transport properties because of their effect on the point-defect concentrations. The activity of enstatite plays an important role in the point-defect chemistry of olivine.     

Cargo spillage at an iron ore unloading terminal

Dust deposition in the sea at an iron ore unloading terminal in the Firth of Clyde, Scotland, was measured by means of sediment collectors placed 10 m above the sea bed on the outer face of the unloading jetty. A ‘background’ sedimentation of up to 64 g m^?2 day^?1 of non-ferrous material was obtained with no ships in port. During unloading dust quantities up to 18 021 g m^?2 day^?1 were obtained, but the quantities depended on the type of ore unloaded, and much smaller quantities of sediment were obtained with ores less prone to fine particle formation. Any ecological effects would involve sea bed benthos, although rates of transportation of the sedimented dust are probably rapid in the immediate vicinity of the ore terminal.     

Heavy metal release from mine tailings into sea water—A laboratory study

In a laboratory experiment to simulate mine tailings disposal into a coastal inlet of British Columbia, initial rapid increases in dissolved iron, copper and lead were observed in the first three hours with subsequent slow decreases to background values within one month. Manganese and nickel increased slowly during the experiment while cadmium and zinc did not increase.     

Calculation of oil concentrations under chemically dispersed slicks

Equations are proposed which describe the diffusion of a plume of oil from chemically dispersed oil slicks into the oceanic water column and which yield estimates of oil concentration as a function of the volume of oil dispersed, time-varying plume area, depth, time, and as a function of a single adjustable parameter, vertical diffusivity. A ‘diffusion floor’ at any desired depth may be included. Experimental data were fitted to the equations to yield an estimate of this diffusivity. It is concluded that oil concentrations can be estimated with a mean error of a factor of three, this high value being attributable to the inherently variable nature of the oceanic diffusion processes. Implications for assessing the toxic effects of dispersed slicks are discussed. It may be possible to calculate acute median lethal water depths and volumes for given organisms subjected to given dispersed oil slicks.     

DDT,DDE, and PCB residues in fish,crustaceans and sediments from the eastern Mediterranean coast of Turkey

Residues of DDE, DDT and PCBs were determined in four different commercial bony fishes: grey mullet, red mullet, striped mullet and gold bandgoat fish, as well as in shrimps, limpets and sediments obtained from the eastern Mediterranean coast of Turkey. The PCB levels in living organisms and sediments were found to be very low, and in most cases below the detection limits. The DDE and DDT values were relatively high compared to PCBs and there was a linear correlation between the organochlorine residue concentrations and the extractable organic material of the analysed samples.     

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.     

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.     

Plasmid incidence in marine bacteria isolated from petroleum polluted sites on different petroleum hydrocarbons

Oil-degrading bacteria isolated from oil spills, an industrial bay, and an offshore oil field by liquid enrichment on crude oils and polynuclear aromatic hydrocarbon compounds were screened for extra-chromosomal DNA. Plasmids were detected in 21% of the strains isolated on whole crude oil and in 17% of the strains isolated on polynuclear aromatic hydrocarbons. Multiple plasmids were observed in 50% of the plasmid-containing strains. Pseudomonas was the predominant genus isolated during the study. Plasmids do not appear to be of importance to these strains during degradation of freshly introduced oil at a nonpolluted site such as might be the case in an ocean oil spill. Plasmids do appear to be significant in the adaptation of Pseudomonas species to chronic petroleum pollution.     

Variation in mercury content of Guillemot feathers over 150 years

The feathers of 277 Black, Common and Brünnich's Guillemot from the Baltic, Kattegat, Faroe Islands and Greenland were analysed for mercury. The levels were found to be higher in the Baltic and the Kattegat compared to the Faroe Islands and Greenland. While the levels were almost constant for the last two areas a substantial increase during this century was found for the Baltic and the Kattegat. In Common Guillemots from the Baltic a decrease was indicated after 1969. In general the mercury levels were higher for Black Guillemots living close to the coast compared to the Uria sp. living off-shore. The inhomogeniety of the mercury load near the shore was indicated by a large individual variation within a colony of Black Guillemots. This variation was reinforced by differences in migration and feeding habits. It has been shown by analysis of individuals recaptured during successive years that the year to year variation of one individual is considerably smaller.It is concluded that chronological series based on feathers from sea birds and museum collections may contribute to the elucidation of the long term trend of mercury pollution at sea.     

Actinomycetes in New York Harbour sediments and dredging spoil

A large number and variety of species of actinomycetes were isolated from sediment samples collected in New York Harbour and from the New York Bight in the course of studies on the distribution of these bacteria in coastal regions. Isolates recovered from the New York Bight sediment were similar to those from other inshore areas, although the total counts were lower. Larger numbers of actinomycetes were recovered from harbour sediments, as well as dredging spoil samples collected from a capped dump site in the New York Bight. The capping operation was monitored and effects on the microbial populations were detected. Selected genera associated with the dredge spoil were determined to be allochthonous, providing useful microbial markers for the dredged material. Many of the microbial species survive in the dump area, but some appear to be metabolically active, perhaps altering the chemical nature of the dumped material.