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81.
Tetsuro Agusa Kumiko Nomura Takashi Kunito Yasumi Anan Hisato Iwata Nobuyuki Miyazaki Ryo Tatsukawa Shinsuke Tanabe 《Marine pollution bulletin》2008,57(6-12):807
Concentrations of 19 trace elements (V, Cr, Mn, Fe, Co, Cu, Zn, Se, Rb, Sr, Mo, Ag, Cd, Sb, Cs, Ba, Tl, Hg, and Pb) were determined in the liver of the striped dolphins (Stenella coeruleoalba) collected around Japan during 1977–1982 to examine the sex difference, age dependence, and interrelationships among trace elements. Tissue distribution of trace elements was also investigated in one adult and one fetus specimens. Generally, concentrations of Se, Sr, Ag, Cd, Cs, Ba, Hg, and Pb were higher in the tissues of adult than those of fetus, whereas the opposite trend was observed for Cr and Tl. There were no significant sex differences in the trace element levels in the liver. Significant positive correlations between age (0–26.5 years) and hepatic concentrations were found for Ag, Se, Hg, V, Fe, Pb, and Sr, suggesting their age-dependent accumulation in the liver. In contrast, hepatic concentrations of Mn and Zn decreased with age. Significant positive relationships were observed between Se, and Hg, Ag, V, Fe, and Sr in the liver. 相似文献
82.
83.
N. Creighton 《Marine pollution bulletin》2010,60(10):1815-1821
The glassfish, Ambassis jacksoniensis, is a key, mid-level species in an estuarine food web on the east coast of Australia. Estuaries are subject to contamination from urban and industrial activities. The biokinetics of Cd, Se and Zn accumulation by glassfish from water and food were assessed using radioisotopes. Metal uptake from water was not regulated over the range of water metal concentrations examined. Metal uptake from food was assessed using brine shrimp (Artemia sp.) fed radio-labelled algae. The assimilation efficiency from food was 9.5 ± 2.5%, 23 ± 2.2% and 4.6 ± 0.6% for Cd, Se and Zn, respectively. The potential for biomagnification was low for all metals. Food is the main metal uptake pathway for glassfish, with 97%, 99% and 98% of the uptake of Cd, Se and Zn, respectively, estimated to be from food. 相似文献
84.
Magmatic mineralization and hydrothermal enrichment of the High Grade Zone at the Lac des Iles palladium mine, northern Ontario, Canada 总被引:2,自引:0,他引:2
The economic mineralization of Pd at the Lac des Iles mine occurs in the gabbroic rocks of the Mine Block Intrusion in the 2.69 Ga Lac des Iles Intrusive Complex. The complex intruded the tonalitic rocks of the Lac des Iles greenstone belt in the Wabigoon Subprovince of the Superior Province of Canada. We conducted a detailed study on the Pd mineralization in the southern Roby Zone and the Twilight Zone. Sulphide minerals commonly display exsolution textures where pentlandite and chalcopyrite are exsolved from pyrrhotite. Sulphur contents from these zones display positive correlations with the contents of platinum group elements (PGE), Se, and Te, suggesting a magmatic origin of the mineralization where PGE were concentrated in immiscible sulphide melt in the parental magmas. The average ratios of Se/S (703±192×10–6) and Te/S (192±104×10–6) in the two zones are higher than the primitive mantle values of ~300×10–6 and ~48×10–6, respectively. The high ratios are consistent with the derivation of their parental magmas from a depleted mantle source. The High Grade Zone forms a narrow northwest-trending zone in the margin of the Roby Zone, and is hosted by an intensely altered clinopyroxenite/melanogabbroic unit. It contains two mineral assemblages; millerite + siegenite ± chalcopyrite ± pyrite co-existing with hornblende + plagioclase ± quartz ± carbonate, and pyrite ± chalcopyrite with chlorite + actinolite ± albite ± quartz ± carbonate. The ore is high in Pd (mean Pd/Pt ratio of 16.5; up to 25) compared to the southern Roby Zone and Twilight Zone where the Pd/Pt ratios are ~8. It shows positive correlations between Se and Te and between Se and immobile metals, such as Ni and Co. The data suggest a primary magmatic origin of mineralization of the High Grade Zone, but there is substantial scatter on diagrams involving S, such as the plot between S and Se. The evidence suggests that the primary magmatic mineralization was followed by hydrothermal transport of mobile elements. Using the relationships between Se and metals, the ore most likely had 0.8–2 ppm Pt and 8–21 ppm Pd during the primary mineralization. The subsequent hydrothermal activity resulted in the enrichment of Pd by up to 40 ppm. The lack of fluid pathways in the High Grade Zone and the distribution of the zone are consistent with magmatic-hydrothermal activity by aqueous fluids exsolved from the parental magmas of the Roby Zone and High Grade Zone. Sulphide minerals from the southern Roby Zone, Twilight Zone, and High Grade Zone have similar 34S values, ranging from 0.0 to +1.5. The data are consistent with the derivation of S from the mantle. In individual samples from the southern Roby Zone and High Grade Zone, pyrite shows lower 34S than chalcopyrite, suggesting isotopic disequilibrium of S. This likely reflects the crystallization and re-crystallization of sulphide minerals over a wide range of temperatures.Editorial handling: B. Lehmann 相似文献
85.
Selenomethionine (SeM) is an organic toxicant that is present in seleniferous environments. No kinetic data is yet available
regarding SeM reactions in coal mine environments, where selenium (Se) toxicity is a potential concern. A kinetic study was
conducted on two reclaimed coal mine soils (Typic Torriorthents) from Wyoming having sandy and clayey textures. Four levels
of SeM treatments (0, 50, 100 μM, and plant amendment from the mine vegetation) were reacted with the soils for 4, 7, 14,
28, 42, 56, and 84 days to characterize the kinetic behavior of overall SeM disappearance from soil solutions. Detection of
SeM in soil solutions at the control level (0 μM SeM) indicated occurrence of indigenous SeM in the soils. In the plant-amended
soil solutions, much greater concentrations of SeM were observed as compared with the soil-only systems. This indicated the
plant material was a more potential source of SeM than the mine soils. A time-dependent loss in solution SeM concentrations
was observed for both soils under 0, 50, 100 μM SeM treatments. For the soil-plant mixtures, the solution SeM concentration
increased initially, reached a maximum after 14 days, and then decreased thereafter. In the plant-amended soil solutions,
SeM concentrations at all time intervals were higher for the sandy as compared to the clayey soil. At 50 and 100 μM SeM treatments,
the solution pH was linearly related to the percentages of SeM disappeared from the solutions; greater percentage of SeM was
removed from solutions at comparatively lower pH levels, which was ≥90% at pH 7.7 for both soils. Solution SeM concentrations
decreased exponentially with time following first-order kinetic reactions. Under all applications (except for the control),
C
0 (SeM concentration at t=0) values for the sandy soil were greater than those determined for the clayey soil, indicating higher solution SeM availability
for the former and more SeM retention by the latter at t=0. Comparison of C
0 in controls (0 μM SeM addition) suggested greater indigenous SeM in the clayey soil. For both soils, C
0 values under different treatments followed the order, (soil+100 μM)>(soil+50 μM)>(soil+0 μM). The specific reaction rate
constants (K
r) of SeM for both soils were similar (0.031 and 0.029 day–1 for sandy and clayey soils, respectively); low K
r values indicated that SeM loss from our reclaimed coal mine soil solutions would follow rather slow kinetics. The half-life
(t
0.5) of SeM varied from 15 to 55 days depending on treatment level. The knowledge obtained from this study should contribute
in developing time-based Se reclamation strategies in coal mine environments.
Received: 18 September 1995 · Accepted: 28 December 1995 相似文献
86.
环境中硒存在形式的研究现状 总被引:33,自引:4,他引:33
已发现107种硒的独立矿物,并随着研究的深入,还会有新的硒矿物发现。对硒的形态和结合态的研究富硒区土壤、煤及黑色岩石中硒是受关注的对象。“分子级”水平的硒形态研究,可能是下一步研究的热点。 相似文献