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1.
CharlotteA.Bowman PeterT.Bobrowsky OlleSelinus 《《幕》》2003,26(4):270-278
The interdisciplinary fieldresponds to the need to betterof “Medical Geology“ understand the relationships between human health and our surrounding environment. The influence of earth resources, natural environmental factors and land-use on human health has long been recognized, dating back to ancient Rome and Peru‘s Inca civilization. Today links between the natural environment and health can be found throughout the world. This review introduces the historical context of this particular type of research, contrasts the direct geological and indirect natural hazard influences on healthas a framework of study, elaborates on pathways of elemental accumulation in the body and provides examples of specific geochemical behaviours and diseases that are often associated with either too much or not enough of certain elements which comprise the Earth. 相似文献
2.
The natural human female hormones oestrone and 17β-oestradiol have been implicated in the disruption of endocrine systems in some wildlife adjacent to sewage effluents. The sorption behaviour of these two compounds under estuarine conditions was studied by spiking either 2.55 μg of oestrone or 2.65 μg of 17β-oestradiol in kinetic experiments. In equilibrium experiments, 3 ng of oestrone or 3.2 ng of 17β-oestradiol was added in each of the centrifuge tubes. Sorption onto sediment particles was relatively slow, with sorption equilibrium being reached in about 70 and 170 h for oestrone and 17β-oestradiol, respectively. The effects of a variety of environmental parameters on sorption were studied including salinity, sediment concentration (SC), the presence of a third phase, particle size and, also, surfactant concentrations. Results show that although salinity did not induce any statistically significant effect on the sorption of 17β-oestradiol, it did statistically enhance the sorption of oestrone, and a salting constant of 0.3 l mol−1 was derived. The partition coefficient for both compounds decreased with increasing sediment concentration, a phenomenon that has been widely reported and attributed to the presence of colloids (which could enhance dissolved concentrations). In this paper, the true partition coefficients for sediment particles (Kptrue) and colloidal particles (Kctrue) have been calculated, and a Kptrue value of 141 and 102 ml g−1 was obtained for oestrone and 17β-oestradiol, respectively. In addition, Kctrue values for oestrone (222×102 ml g−1) and 17β-oestradiol (135×102 ml g−1) were two orders of magnitude higher than their respective Kptrue values, suggesting that the colloidal particles are significantly stronger sorbents for natural oestrogens than sediment particles. Particles of different sizes were found to have different partition coefficients due to the strong relationships between partition coefficients for the two compounds and particulate organic carbon (POC) contents and specific surface areas (SSAs). The presence of a surfactant was shown to reduce the partition coefficients for the two compounds, although its concentrations being used were higher than those normally found in the natural environment. 相似文献
3.
The goal of this study is to estimate the efficiency of dewatering operations in Alassio Beach, north Italy by following an integrated approach which included beach volume calculations, daily mapping of the shoreline position, examination of specific beach widening events and daily comparisons of morphodynamic characteristics of the drained beach versus a control section which included wave run-up, bar patterns, rip migration, evolution of the berm and cusp morphology. 相似文献
4.
Bruce R. Bowman 《Celestial Mechanics and Dynamical Astronomy》1979,19(2):203-211
Analysis of high precision 2-day mean orbital elements of several U.S. Navy navigation satellites is presented. The combined analytical-numerical method for the computation of the elements from the Defense Mapping Agency precision ephemerides is described. The precision of the semimajor axis and the inclination orbital elements are determined to be 2 cm and 0.016 respectively. The 28th degree and 27th order terms of the geopotential field are determined with the mean elements. 相似文献
5.
ABSTRACTOil spill forecast modelling is typically used immediately after a spill to predict oil dispersal and promote mobilisation of more effective response operations. The aim of this work was to map oil dispersal after the grounding of the MV Rena on Astrolabe Reef and to verify the results against observations. Model predictions were broadly consistent with observed distribution of oil contamination. However, some hot spots of oil accumulation, likely due to surf-zone and rip current circulation, were not well represented. Additionally, the model was run with 81 differing wind conditions to show that the events occurring during the grounding represented the typical likely behaviour of an oil spill on Astrolabe Reef. Oil dispersal was highly dependent on prevailing wind patterns; more accurate prediction would require better observations of local wind patterns. However, comparison of predictions with observations indicated that the GNOME model was an effective low-cost approach. 相似文献
6.
The Campos, Santos and Pelotas basins have been investigated in terms of 2D seismo-stratigraphy and subsidence. The processes controlling accommodation space (e.g. eustacy, subsidence, sediment input) and the evolution of the three basins are discussed. Depositional seismic sequences in the syn-rift Barremian to the drift Holocene basin fill have been identified. In addition, the subsidence/uplift history has been numerically modeled including (i) sediment flux, (ii) sedimentary basin framework, (iii) relation to plate-tectonic reconfigurations, and (iv) mechanism of crustal extension. Although the initial rift development of the three basins is very similar, basin architecture, sedimentary infill and distribution differ considerably during the syn-rift sag to the drift basin stages. After widespread late Aptian–early Albian salt and carbonate deposition, shelf retrogradation dominated in the Campos Basin, whereas shelf progradation occurred in the Santos Basin. In the Tertiary, these basin fill styles were reversed: since the Paleogene, shelf progradation in the Campos Basin contrasts with overall retrogradation in the Santos Basin. In contrast, long-term Cretaceous–Paleogene shelf retrogradation and intense Neogene progradation characterize the Pelotas Basin. Its specific basin fill and architecture mainly resulted from the absence of salt deposition and deformation. These temporally and spatially varying successions were controlled by specific long-term subsidence/uplift trends. Onshore and offshore tectonism in the Campos and Santos basins affected the sediment flux history, distribution of the main depocenters and occurrence of hydrocarbon stratigraphic–structural traps. This is highlighted by the exhumation and erosion of the Serra do Mar, Serra da Mantiqueira and Ponta Grossa Arch in the hinterland, as well as salt tectonics in the offshore domain. The Pelotas Basin was less affected by changes in structural regimes until the Eocene, when the Andean orogeny caused uplift of the source areas. Flexural loading largely controlled its development and potential hydrocarbon traps are mainly stratigraphic. 相似文献
7.
8.
Complete chemical analyses of metamorphic hornblendes: implications for normalizations,calculated H2O activities,and thermobarometry 总被引:1,自引:0,他引:1
Michael A. Cosca Eric J. Essene Johns R. Bowman 《Contributions to Mineralogy and Petrology》1991,108(4):472-484
Twenty-two hornblendes separated from amphibolites and granulites of the Grenville Orogen of Ontario have been quantitatively analyzed for major and minor elements by electron microprobe, for FeO/Fe2O3 by wet chemistry, and for H2O by manometric measurement as H2. Hornblende formulae were calculated on the basis of 24O+OH+Cl+F. Most samples are magnesio-hornblendes, ferroan pargasitic hornblendes and ferroan hastingsitic hornblendes, with weight fractions of Fe3+/(Fe2++Fe3+) ranging from 0.15 to 0.50. An oxy-amphibole component of 0–25 mol%, with an average value of 17 mol%, is obtained for these complete analyses. When compared with structural formulae determined solely from microprobe data, normalization based on 13=Si+Ti+Al+Fe+Mn+Mg cations provides the best approximation to hornblende formulae calculated from the complete analyses. Less satisfactory agreement is obtained from a normalization scheme based on 15=Si+Ti+Al+Fe+Mn+Mg+Ca, while worst agreement is obtained from normalization to 23 oxygens assuming all Fe is Fe2+. No normalization scheme based on microprobe data alone consistently replicates the measured FeO, Fe2O3, and H2O; accurate determination of these values requires complete chemical analysies. Ionic solution models previously have been proposed to evaluate the activity of Ca2Mg5Si8 O22(OH)2(a
Trem) in hornblende for use in equilibria that constrain the activity of H2O (a
H
2O) in igneous and metamorphic rocks. Application of ionic models to typical hornblendes produces low a
Trem (usually<0.01), consequetly yielding extremely low a
H
2O. If an oxy-amphibole component is present, the calculated a
Trem and H2O is further reduced. An oxy-amphibole component of 25% reduces the calculated H2O activity and that of any hydroxyl-amphibole component by 50% below that calculated with simplified assumptions regarding X
OH in the hydroxyl site (i.e., X
OH=1, or X
OH=1–X
Cl–X
f). Thus, methods of amphibole normalizations appear to have a substantial effect on calculated amphibole and H2O activites. Before quantitative hornblende thermobarometry can be calibrated and applied, the amounts of FeO, Fe2O3 and H2O must be measured in order to fully characterize hornblende solid solutions.Contribution No. 478 from the Mineralogical Laboratory, University of Michigan 相似文献
9.
Tree stem (>2 m tall) mortality was assessed following a late dry‐season wildfire across a seasonally flooded elevation gradient at Workshop Jungle, near Darwin, in the Northern Territory of Australia. For all species combined, dead stems had significantly smaller diameter at breast height (dbh) than living stems. Assessment of tree‐stem damage following a tropical cyclone at Cobourg Peninsula, NT, revealed that damaged stems had significantly greater dbh than undamaged stems for all tree species sampled across a boundary between monsoon rainforest and savanna. A greater proportion of stems were damaged by the cyclone than by the fire (28 per cent as against 18 per cent), although there were considerable between‐community differences in the proportion of damaged stems at the two sites. The fire caused little impact (<10 per cent) on total basal area of three different forest communities on the elevation gradient at Workshop Jungle. The cyclone was found to cause >50 per cent damage to total basal area of three different communities on Cobourg Peninsula. It is suggested that the combination of a cyclone followed by an intense fire in storm debris could potentially destroy a monsoon rainforest through its impact on all tree‐size classes. This may explain why some monsoon rainforests rapidly contracted following Cyclone Tracy that destroyed the city of Darwin on Christmas Day, 1974. 相似文献
10.