同位素稀释技术在土壤微量元素地球化学活性分析中的应用

土壤中微量元素的地球化学活性是评价土壤质量以及环境风险的重要指标.现有的分析方法虽多,但因技术限制难以适用于所有类型的土壤,致使标准不统一,对科研工作提供的参考性不足.同位素稀释技术(isotopic dilution technique)对固/液交换过程造成的扰动极小,近年来被越来越多的研究人员认为是量化土壤微量元素...     

基于土地质量地球化学调查成果的土壤地球化学分区

1∶25万土地质量地球化学调查工作的开展,在特色土地资源开发、土壤污染防治、脱贫攻坚等方面做出了重要贡献.研究区地处六盘山集中连片特困地区,依据区域内2638件土壤样品的53项元素指标测试结果,利用因子分析方法划分了10个元素指标组合分区,结合区域地球化学特征分布及规律进行了分析和评价.研究区地球化学分区不仅受自然环境...     

沉积物中磷形态的化学连续提取法应用研究

对水体沉积物中磷的环境地球化学研究中较普遍采用的7步法连续提取磷分级方案在实际应用中出现的一些问题进行了探讨。从该方法对水系沉积物成分分析标准物质GSD—12及太湖沉积物的分析结果看，该方法的应用中各形态的重现性问题必须得到重视，尤其是闭蓄态磷的提取中，实际操作中要尽量避免因沉积物固结容器底部而降低提取剂的提取效率，对于提取离心液过滤难的问题也一定要解决好。可交换态磷、铝磷和铁磷的提取液由于磷浓度低，可以不将其后的漂洗液混入后测定，以提高待测液中磷的浓度。另外，从GSD—12与太湖沉积物中磷形态特征的相似性看，GSD—12可以考虑作为淡水水体沉积物磷形态分级的标准物质，从而解决不同文献、不同研究项目在沉积物形态分析方面缺乏可比性的问题。     

Immobilization of soil copper using organic and inorganic amendments

This experiment aimed to immobilize Cu in polluted agricultural soils via the application of agrochemicals to reduce its bioavailability to plants. A greenhouse pot experiment was established using a Cu contaminated vineyard topsoil collected from a farm in Greece. The soil was mixed with inorganic [i.e., zeolite (Z), Al‐oxide (AX), Mn‐oxide (MX), and phosphate rock (PR)] as well as organic amendments [i.e., activated charcoal (AC), commercial peat soil material (CP), and compost from olive oil processing wastes (COW)] with an application rate of 2.5% and cultivated by corn (Zea maize). After plant harvesting, Cu was measured separately in the aboveground biomass and roots, respectively, whereas the soil samples were analyzed for DTPA‐extractable and geochemical fractions of Cu (soluble + exchangeable fraction, sorbed and carbonate fraction, Fe‐/Mn‐oxides fraction, and organic fraction). The immobilizing agents, except MX, reduced the soluble plus exchangeable Cu in the treated soil. The lowest concentrations of the soluble plus exchangeable Cu occurred in the soil amended with AC followed by CP, AX, COW, PR, and Z, respectively. The amendments decreased the uptake of Cu by corn. Concentrations of Cu were between 11 and 38% lower in the above ground biomass and 19 and 48% lower in the roots than the control. The organic amendments were more effective than the inorganic additives. The AC was the most effective organic additive and AX was the most effective inorganic amendment.     

天山荒漠景观内蒸发地球化学垒的研究

天山荒漠景观内的蒸发地球化学垒可分为碳酸盐蒸发垒、石膏蒸发垒和易溶盐蒸发垒。这些蒸发垒沿天山山脉呈带状分布 ,自天山山脉至两侧盆地依次分布碳酸盐蒸发垒、石膏蒸发垒和易溶盐蒸发垒。土壤中碳酸盐的积聚导致Mn、Ti、Fe、V、Sc、Cu、Co和B等元素含量的降低。石膏的富集常伴随着土壤中B和Sr含量的增加。随易溶盐的大量积累 ,元素B的聚集非常明显 ,而Mn、Fe、Ti、V、K、Ba、Li、F和Zn等元素含量则明显降低。蒸发地球化学垒对元素的生物有效性也有较明显的影响。碳酸盐的积累明显减低了Fe、Cu、B等元素的生物有效性 ,F元素在碳酸盐蒸发垒内CO2 -3 和HCO-3 含量较高的土壤中生物有效性较高。在易溶盐蒸发垒内元素B有较强的生物有效性     

渭河流域全新世古洪水滞流沉积物地球化学特征

对渭河流域野外实地详细调查,在渭河中游发现了具有典型古洪水滞流沉积物(SWD)的全新世黄土-古土壤沉积剖面。根据地层学对比和OSL测年,确定渭河流域在3200-2800aB.P.发生了特大古洪水事件。对沉积物地球化学特征分析表明,SWD为典型的古洪水滞流沉积物,各化学元素和氧化物的变异系数大,元素数据分布较为分散;Fe2O3、Al2O3、Ba、Cr、Cu、V、Rb含量高于S0和L0,SiO2、Zr含量低于S0和L0;化学元素粒度效应表明,SWD粒径小、粘粒强,是在滞流环境的水动力条件下沉积而成;通过气候指标Rb/Sr和Ba/Sr分析,认为古洪水滞流沉积物(SWD)记录的3200-2800aB.P.的特大古洪水事件,是在全新世大暖期结束之际,因夏季风减弱、气候系统不稳定、降水变率较大所导致的。     

Soil Microbial Community Diversity and Its Relationships with Geochemical Elements under different Farmlands in Shouguang,China

The aims of this study were to investigate soil microbial community characteristics and their interrelationships with soil geochemistry under different farmlands in Shouguang, China. The traditional dilution plate counts, BIOLOG system, and fatty acid methyl ester (FAME) analyses were used to assess microbial populations, substrate utilization, and fatty acid profiles. The number of aerobic heterotrophic bacteria varied significantly among untilled land, maize, and mungbean fields. The amounts of actinomycetes, fungal fatty acids, and Gram-positive/Gram-negative bacteria ratios varied greatly among celery, tomato, and aubergine fields. In the tomato field, the soil microbial community characteristics were significantly different from other fields. Principal component analysis of BIOLOG and FAME data revealed differences in the catabolic capability and fatty acid profiles of soil microbial communities among different farmlands. Spearman correlation analyses showed that in these sand clay soils of Shouguang, microbial communities in different farmlands were closely correlated with soil geochemical elements, moisture, and organic matter.     

关于淤泥回地的几点思考

淤泥是水体活性污泥和径流泥沙的絮聚体,结构良好,含丰富有机质、N、P、K、微量元素和生物活性物质等,是良好资源,可返回到陆地培肥改良土壤。逆地球化学过程让淤泥回到陆地,可减弱水体内源释放,又可利用淤泥资源,减少化肥用量,还可解决淤泥堆放处置难题,治理污染,改善环境。但淤泥同时含有重金属、有机污染物和致病菌(虫)等,限制着淤泥回地使用。因此,要谨慎、分别地将淤泥回地。     

近7.0-0.73MaBP期间甘肃临夏盆地古气候演变的沉积物地球化学记录

位于青藏高原东北边缘临夏盆地新生代沉积蕴含了丰富的有关青藏高原隆升和环境演变信息。近７．０－０．７３ＭａＢＰ期间沉积物地化元素含量波动特征表明,具相同或相近表生地化性质的元素含量波动呈现大致相同的特征。由常量元素氧化物所揭示的此期间临夏盆地温湿变化明显地可以分成几个阶段,即７．０－５．３５ＭａＢＰ,虽有冷干与暖湿波动,但总体上却呈现出一种较为和缓、稳定的气候特征;至５．３５ＭａＢＰ前后,出现一具全球意义的冷峰,随后气候进入冷干与暖湿频繁、大幅剧烈波动的时期,可能同青藏高原此时开始的整体隆升并导致亚洲季风开始建立但极不稳定的状况有关。而３．４Ｍａ和２．９０Ｍａ两次强烈的构造运动的发生很可能使得青藏高原隆升至一个关键高度,此时亚洲季风已稳定建立,地化元素波动平缓,气候环境以冷湿为主要特征,湖相沉积发育。之后,１．６０Ｍａ前后高原再度隆升,导致黄河朔源侵蚀加剧,最终切穿临夏盆地,排干湖水,且此时高原巨大的山体已成为南来湿润气流的障碍,使内陆地区趋于干旱,温带荒漠开始发育,并在其四周广泛地开始了风成黄土的堆积,而黄土堆积中黄土与古土壤的交替出现仍是冷干与暖湿气候特征的反映。因此,近７．０－０．７３ＭａＢＰ期间临夏盆?