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11.
Correlations between heavy metals and organic carbon extracted by dry oxidation procedure in urban roadside soils 总被引:1,自引:0,他引:1
Xue Song Wang 《Environmental Geology》2008,54(2):269-273
The organic fraction in soils has a significant influence on heavy metal transport. In this study, the organic carbon content
was measured by dry oxidation procedure from 21 Xuzhou urban roadside soils to assess the relationships between the concentrations
of heavy metals (Pb, Cu, Zn, and Cr) and the amount of organic carbon. The anthropogenic heavy metals (e.g. Pb, Cu, Zn) were
strongly correlated with organic carbon (denoted by Corg−c) extracted by dry oxidation while natural heavy metal (e.g. Cr) showed no correlation to the Corg−c. The anthropogenic heavy metals were also strongly correlated with the amount of the total carbon. These results show that
the anthropogenic heavy metals are mainly enriched in the organic matter in the Xuzhou urban roadside soils. 相似文献
12.
Distribution of Cd,Pb, Zn and Cu and their chemical speciations in soils from a peri-smelter area in northeast China 总被引:2,自引:0,他引:2
An exploratory study on soil contamination of heavy metals was carried out surrounding Huludao zinc smelter in Liaoning province,
China. The distribution of total heavy metals and their chemical speciations were investigated. The correlations between heavy
metal speciations and soil pH values in corresponding sites were also analyzed. In general, Cd, Zn, Pb, Cu and As presented
a significant contamination in the area near the smelter, comparied with Environmental Quality Standards for Soils in China.
The geoaccumulation index showed the degree of contamination: Cd > Zn > Pb > Cu > As. There was no obvious pollution of Cr
and Ni in the studied area. The speciation analysis showed that the dominant fraction of Cd and Zn was the acid soluble fraction,
and the second was the residual fraction. Pb was mostly associated with the residual fraction, which constituted more than
50% of total concentration in all samples. Cu in residual fraction accounted for a high percentage (40–80%) of total concentration,
and the proportion of Cu in the oxidizable fraction is higher than that of other metals. The distribution pattern of Pb and
Zn was obviously affected by soil pH. It seemed that Pb and Zn content in acid solution fraction increased with increasing
soil pH values, while Cd content in acid soluble fraction accounted for more proportion in neutral and alkaline groups than
acidic one. The fraction distribution patterns of Cu in three pH groups were very similar and independent of soil pH values.
And the residual fraction of Cu took a predominant part (50%) of the total content. 相似文献
13.
A strain of thermophilic fungus Aspergillus fumigatus was cultured with K-bearing minerals to determine if microbe-mineral interactions enhance the release of mineralic potassium. Experiments were carried out in two settings, one with the mineral grains and the fungal cells in direct contact, and the other employing a membrane (pore size 0.22 μm) to separate the two. Measurements over a period of 30 days showed that, irrespective of the experimental setup, the concentration of free K in the culture was drastically higher than those in any of the control experiments where no living organism was present. Moreover, the occurrence of mineral-cell physical contact enhanced potassium release by an additional factor of 3 to 4 in comparison to the separation experiments. For contact experiments, Electron Probe Microanalysis revealed the formation of mycelium-mineral aggregates, and Atomic Force Microscopy imaging further indicated the possible ingestion of mineral particles by the fungus cells. Contrasting to what was observed and expected in control experiments, the potassium solubilization rate showed a positive dependence upon pH when fungi and minerals were mixed directly, and exhibited no correlations with solution acidity if cell-rock contact was restrained. These results appear to suggest that A. fumigatus promoted potassium release by means of at least three likely routes, one through the complexation of soluble organic ligands, another appealing to the immobile biopolymers such as the insoluble components of secretion, and the third related to the mechanical forces in association with the direct physical contact between cells and mineral particles. 相似文献
14.
青藏高原东南木里地区二叠纪苦橄岩的Os-Sr-Nd同位素地球化学研究 总被引:3,自引:2,他引:1
本文报道了在青藏高原东南木里地区发现的二叠纪苦橄岩和与其共生玄武岩的主微量元素地球化学特征以及Os-Sr-Nd同位素组成。苦橄岩和与其共生玄武岩受地壳混染作用影响较小。根据苦橄岩的Ti/Y比值和初始的Os同位素组成,将木里苦橄岩分为两类:高Ti/Y型苦橄岩和低Ti/Y型苦橄岩,其中高Ti/Y型苦橄岩具有高的γ_(Os)= 5.3~ 10.7和ε_(Nd)= 5.9~ 6.4,与全球典型洋岛玄武岩的Os和Nd同位素组成接近,代表了地幔柱源区的同位素特征;而低Ti/Y型苦橄岩具有低的γ_(Os)=-4.1~ 1.2和ε_(Nd)= 3.2~ 5.0,可能表明受到了SCLM(大陆岩石圈地幔)源区物质的混染。与其共生的玄武岩具有低的γ_(Os)=-3.5~-1.6和ε_(Nd)=-0.6~ 0.7,表明其来自于不同于低Ti/Y型苦橄岩也有异于高Ti/Y型苦橄岩的地幔源区,但是也可能受到了SCLM物质的混染。基于Nd-Os同位素的地幔柱与SCLM的二端元混合模型显示:低Ti/Y型苦橄岩可能是SCLM物质组分与地幔柱起源的苦橄质原始岩浆混合形成的;与苦橄岩共生的玄武岩可能是由地幔柱来源的玄武质岩浆与SCLM小比例熔融的熔体混合形成的。 相似文献
15.
16.
阿尔金南缘构造带西段辉绿岩墙群的地球化学特征及构造环境 总被引:5,自引:0,他引:5
对阿尔金南缘构造带西段辉绿岩墙群的岩石学和地球化学的详细研究表明,该区辉绿岩墙群为拉斑系列岩石,其主量元素以中等TiO2(1.19%~1.59%)、高MgO(5.51%~7.88%)、贫K2O(0.04%~0.84%)和P2O5(0.10%~0.20%)、Na2OK2O为特征;高场强元素(HFSE)丰度特征显示其为E-MORB型或过渡型玄武岩质岩石;稀土元素总量相对较高,轻重稀土元素分馏不显著[(La/Yb)N=1.93~3.61,LREE/HREE=3.01~4.10],在球粒陨石标准化配分模式图上呈略富集型.结合玄武岩构造环境判别图解综合分析推测,它们可能形成于一种裂谷向MORB环境过渡的构造环境,即初始小洋盆构造环境. 相似文献
17.
舟山枸杞水域的污损生物生态 总被引:1,自引:0,他引:1
本文系1988年9月~1989年9月在舟山枸杞乌里西岙水域进行挂板试验的结果。共获污损生物135种,其中,近岸的油库码头获77种,远岸的养殖筏获110种。动物以亚热带高盐性种类为主,三角藤壶Balanustrigunus、小海葵Actinia、柯氏分胞孔苔虫Celleporinacostazii、西方三胞苔虫Tricelariaoccidentalis、艾氏美熄Cltiaedwardsi、广口小桧叶螅Sertularellamiurrensis等占优势,藻类常见的有长石莼Ulvalinza、肠浒苔Enteromorphyintestinalis和日本多管藻Polysiphoniajaponica。枸杞污损生物的附着期主要在夏季,附着量也以夏季最大。不同地点附着量的差异极大。夏季由于近岸三角藤壶大量附着,故生物量明显大子远岸,其他季节均是远岸大于近岸。夏季近岸三角藤壶的覆盖面积达100%,生物量达18119g/m2,占污损生物总生物量的98%。故夏季是污损生物防除的主要季节,三角藤壶是防除的主要对象。与1975~1976年嵊山污损生物进行比较,发现两地污损生物的种类组成和群落结构极为相似,说明10多年以来嵊山 相似文献
18.
应用车贝雪夫多项式分析过渡季节(6—7月)澳大利亚冷高压与赤道辐合带的关系,得出了对赤道辐合带北移的主要形势以及过程演变特征,最后用合成方法得到它的演变概念模式,为赤道辐合带的北移影响西太平洋及南海地区提供了中期预报的依据。 相似文献
19.
Characteristics of Scour and Deposition in Front of Breakwaters Under Irregular Broken Clapotis 总被引:1,自引:0,他引:1
First the scour and deposition patterns of the sandy seabed in front of a vertical breakwater under the action of irregular broken clapotis are investigated experimentally and classified into five types: scour type Ⅰ , scour type Ⅱ, scour type Ⅲ, deposition type Ⅰ, and deposition type Ⅱ . Secondly, the processes of formation of scour and deposition patterns are probed in comparison with those induced by regular broken clapotis and standing waves. Thirdly, the criteria for distinguishing scour and deposition patterns under irregular broken clapotis are presented. 相似文献
20.