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1.
广西桂林大岩洞岩溶洞穴土壤中有机氯农药的分布特征 总被引：2，自引：0，他引：2
首次对桂林岩溶区洞穴土壤中有机氯农药的污染状况进行了研究。结果表明,洞穴土壤受到了有机氯农药的轻度污染,其中大气传输对有机氯农药的贡献起主导作用。在17种有机氯农药中,以DDTs、HCHs和氯丹污染为主。在洞穴内部OCP总量为1.19～11.18 ng/g,远低于洞外土壤中的含量(11.41～23.62 ng/g)。在洞内土壤中,HCHs含量高于DDTs,在HCH四种同分异构体中,β-HCH占HCHs的比例远高于其他3种同分异构体。除β-HCH外,其他3种同分异构体的含量分布均匀,可能是由洞穴环境稳定、气候分带等因素造成的。在洞外土壤中,异构体百分比和示踪标志物比值表明周围可能有林丹扣三氯杀螨醇的新近输入。研究区六六六和滴滴涕主要来源于历史上使用的农药的残留。 相似文献
2.
长三角部分地区土壤中22种有机氯农药的分布特征 总被引：1，自引：1，他引：0
针对长三角地区长期工业化对农业生态环境构成较大风险,本文利用气相色谱法对该地区不同利用类型土壤中22种有机氯农药进行测定,研究了有机氯农药的残留状况及其在4条土壤垂向剖面中的分布特征。结果表明,不同利用类型表层土壤中有机氯农药残留平均值为工业园区菜地(139.87 ng/g)工业园区荒地(103.1 ng/g)农业区传统菜地(26.27 ng/g)农业区水稻田(2.50 ng/g)。表层土壤中DDTs和HCHs是主要污染物,DDTs含量为0.14~485.73 ng/g(均值44.43 ng/g),HCHs含量为0.69~66.69 ng/g(均值7.73 ng/g),(DDD+DDE)/DDTs值表明该地区近期外源DDTs输入较少。土壤剖面样品分析表明,DDTs和HCHs的含量均随土壤深度增加而迅速降低,这与剖面土壤包气带岩性均以黏土和亚黏土为主,削弱了地表径流对有机氯农药的垂直迁移动力有关。本研究可为控制和改善该地区污染状况提供相关数据。 相似文献
3.
利用GC-ECD定量测定了沈阳郊区21个表层土壤样品中有机氯农药(OCPs)的含量,并对其残留特征、可能来源及生态风险进行了分析。结果表明,研究区表层土壤中OCPs的检出率达到95.2%,残留量最高值达到111.67 ng·g-1,平均值26.91 ng·g-1,其中以六六六(HCHs)和滴滴涕(DDTs)为主。与国内其他城市土壤中OCPs含量相比,沈阳郊区表层土壤HCHs和DDTs残留属于较低水平,但HCB残留属于较高水平。研究区OCPs的来源解析表明OCPs主要来自环境中的早期残留和近期林丹的使用,六氯苯(HCB)的来源还应包括工业生产。相关性分析说明土壤中总有机碳和水溶盐含量是影响OCPs残留的重要因素。生态风险评价显示表层土壤中DDTs类有机氯农药对该区生物可能仍存在生态风险。 相似文献
4.
新江湾城开发区表层土壤中有机氯农药和多氯联苯的分布特征 总被引：4，自引：2，他引：2
利用电子捕获检测器气相色谱法(GC-ECD)测定新江湾城表层土壤中有机氯农药(OCPs)和多氯联苯(PCBs),六六六类(HCHs)和滴滴涕类(DDTs)化合物均被检出,HCHs含量为0.81~2.84 ng/g,平均1.90 ng/g;DDTs含量为9.37~130.8 ng/g,平均43.9 ng/g。HCHs都未超过国家土壤环境质量标准的一级水平,但是有两个站点的DDTs超过国家土壤环境质量标准的一级水平。7种多氯联苯(7PCBs)含量为1.83~8.46 ng/g,平均3.99 ng/g,以四氯代PCB 52和六氯代PCB 138残留最高。PCBs污染主要集中在火力发电厂处,并向周边蔓延,反映了PCBs污染的来源与电力设备有关,其污染来源很有可能来自历史上变压器油泄漏物的残留及来自工业区的新的PCBs输入。 相似文献
5.
广州市海珠区有机氯农药污染状况及其土-气交换 总被引：5，自引：3，他引：2
通过在冬夏两季对广州市海珠区表层土壤和空气样品中有机氯农药的采样和分析,对有机氯农药残留现状和潜在生态风险进行了研究。结果表明,土壤中六六六类(HCHs)含量水平在2007年冬季和2008年夏季分别为0.57~8.77 ng/g和0.30~14.9 ng/g,平均值分别为2.87 ng/g和3.04 ng/g,都未超过国家土壤环境质量标准的一级自然背景值。冬季和夏季滴滴涕类(DDTs)含量水平分别为3.69~697.7 ng/g和0.88~263.3 ng/g,平均值分别为85.5 ng/g和39.4 ng/g。海珠区部分地点DDTs超过国家土壤环境质量标准的一级自然背景值。DDTs为该区域表层土壤中主要的有机氯农药残留。在研究区域对逸度模型进行了初步应用。 相似文献
6.
重庆老龙洞地下河流域水体有机氯农药污染及来源初步研究 总被引：5，自引：4，他引：1
为查明重庆老龙洞地下河流域有机氯农药的污染情况及其特征和来源,通过气相色谱-微池电子捕获检测器(GC-μ ECD)检测水体OCPs含量.结果表明研究区水样中受到了有机氯农药不同程度的污染.α-HCH是研究区水体HCHs主要成分,HCHs的残留主要来自于大气长距离传输.DDTs的主要成分各采样点不尽相同.DDTs的输入为历史上工业DDTs的使用且在水体中其主要以好氧转化为主.与国内外河流相比较,老龙洞地下河流域水体有机氯农药含量处于较高水平. 相似文献
7.
北京郊区地表水中有机氯农药残留水平及特征 总被引：5，自引：0，他引：5
有机氯农药滴滴涕(DDT)、六六六(HCH)等化学性质非常稳定,很难生物降解,对环境及人类健康构成了严重威胁。尽管我国从1983年起已禁止使用,但现在的土壤、水等环境样品中仍有不同程度的检出。水资源是自然环境的主要组成要素,又是农业生产的重要自然资源。以往已有学者对北京部分河流地表水中有机氯农药残留进行过研究,发现存在不同程度水体污染。近年来,经过各方大力控制水体污染和环境治理,北京地区地表水中仍有有机氯农药残留,其残留现状是人们十分关心的重要问题。因此本文选择北京郊区为研究区域,采集了温榆河、北运河、延庆、房山、昌平、顺义等地区地表水,分析了水体中DDTs和HCHs污染物的含量以及分布情况,结果表明DDTs、HCHs在北京郊区地表水中均有不同程度的检出,DDTs含量为ND~1398 ng/L,HCHs含量为387~14642 ng/L。本文同时研究了DDT与其代谢产物DDE、DDD的组成比例以及HCH同分异构体的组成特征,对北京郊区地表水中DDTs和HCHs的污染来源进行了简要分析。 相似文献
8.
为查明重庆老龙洞地下河流域有机氯农药的污染情况及其特征和来源,通过气相色谱-微池电子捕获检测器(GC-μECD)检测水体OCPs含量。结果表明研究区水样中受到了有机氯农药不同程度的污染。α-HCH是研究区水体HCHs主要成分,HCHs的残留主要来自于大气长距离传输。DDTs的主要成分各采样点不尽相同。DDTs的输入为历史上工业DDTs的使用且在水体中其主要以好氧转化为主。与国内外河流相比较,老龙洞地下河流域水体有机氯农药含量处于较高水平。 相似文献
9.
大石围天坑群土壤中有机氯农药的分布与富集特征 总被引：1，自引：0，他引：1
选择典型的岩溶地区广西乐业大石围天坑群为研究区,采集不同岩溶地形的土壤,利用 GC-ECD 气相色谱仪测定六六六(HCHs)和滴滴涕(DDTs)两种有机氯农药的浓度.结果表明,大石围天坑群地表土壤、天坑绝壁土壤、天坑底部土壤以及地下河(洞穴)土壤中的 HCHs 和 DDTs 平均浓度分别为0.06 ng/g 和0.02 ng/g、0.31 ng/g 和0.27 ng/g、0.96 ng/g 和0.28 ng/g 以及0.14 ng/g 和0.10 ng/g.研究区土壤中有机氯农药总检出率为:天坑地表<天坑绝壁<天坑底部<地下河(洞穴),随高程降低而增高;有机氯农药(OCPs = HCHs + DDTs)浓度的空间分布特征为:天坑底部>天坑绝壁>地下河(洞穴)>天坑地表,天坑底部 OCPs 浓度明显高于顶部;因此,大石围天坑呈现明显的有机污染物“冷陷阱效应” 相似文献
10.
沈阳市细河周边农田土壤和大气中有机氯农药和多氯联苯初步研究 总被引：2，自引：1，他引：1
在2010年5月调查了沈阳市细河沿岸表层土壤中有机氯农药(OCPs)和多氯联苯(PCBs)的污染现状,评价土壤中OCPs残留的生态风险。沈阳细河沿岸表层土壤中HCHs浓度范围分别为2.32～15.90 ng/g,平均浓度为8.99ng/g。DDTs浓度范围分别为9.06～111.6 ng/g,平均浓度为37.08 ng/g。7种PCBs异构体总平均浓度为1.01ng/g,大部分采样点OCPs和PCBs未超过国家土壤环境质量标准,推断近期可能有林丹的使用但没有新的DDTs污染源输入,但个别地点土壤中的DDTs残留浓度对生态系统健康构成了潜在的威胁。大气蒸汽态HCHs浓度为18.97 ng/m3;DDTs浓度为42.27 ng/m3;PCBs浓度为20.59 ng/m3。研究表明大气长距离传输对该区域的OCPs污染也有较为明显的影响。初步运用逸度概念模型进行分析,发现HCHs和DDTs的逸出方向为从土壤向大气挥发。 相似文献
11.
Emily Keeble David I. Whiteside Michael J. Benton 《Proceedings of the Geologists' Association. Geologists' Association》2018,129(2):99-119
Pant-y-ffynnon Quarry in South Wales yielded a rich cache of fossils in the early 1950s, including articulated specimens of new species (the small sauropodomorph dinosaur Pantydraco caducus and the crocodylomorph Terrestrisuchus gracilis), but no substantial study of the wider fauna of the Pant-y-ffynnon fissure systems has been published. Here, our overview of existing specimens, a few described but mostly undescribed, as well as freshly processed material, provides a comprehensive picture of the Pant-y-ffynnon palaeo-island of the Late Triassic. This was an island with a relatively impoverished fauna dominated by small clevosaurs (rhynchocephalians), including a new species, Clevosaurus cambrica, described here from a partially articulated specimen and isolated bones. The new species has a dental morphology that is intermediate between the Late Triassic Clevosaurus hudsoni, from Cromhall Quarry to the east, and the younger C. convallis from Pant Quarry to the west, suggesting adaptive radiation of clevosaurs in the palaeo-archipelago. The larger reptiles on the palaeo-island do not exceed 1.5?m in length, including a small carnivorous crocodylomorph, Terrestrisuchus, and a possible example of insular dwarfism in the basal dinosaur Pantydraco. 相似文献
12.
Gilles Serge Odin 《Comptes Rendus Geoscience》2002,334(6):409-414
Lithostratigraphy, physicochemical stratigraphy, biostratigraphy, and geochronology of the 77–70 Ma old series bracketing the Campanian–Maastrichtian boundary have been investigated by 70 experts. For the first time, direct relationships between macro- and microfossils have been established, as well as direct and indirect relationships between chemo-physical and biostratigraphical tools. A combination of criteria for selecting the boundary level, duration estimates, uncertainties on durations and on the location of biohorizons have been considered; new chronostratigraphic units are proposed. The geological site at Tercis is accepted by the Commission on Stratigraphy as the international reference for the stratigraphy of the studied interval. To cite this article: G.S. Odin, C. R. Geoscience 334 (2002) 409–414. 相似文献
13.
The effect of water on accessory phase solubility in subaluminous and peralkaline granitic melts 总被引：4，自引：0，他引：4
The solubilities of columbite, tantalite, wolframite, rutile, zircon and hafnon were determined as a function of the water contents in peralkaline and subaluminous granite melts. All experiments were conducted at 1035 °C and 2 kbar and the water contents of the melts ranged from nominally dry to approximately 6 wt.% H2O. Accessory phase solubilities are not affected by the water content of the peralkaline melt. By contrast, solubilities are affected by the water content of the subaluminous melt, where the solubilities of all the accessory phases examined increase with the water content of the melt, up to 2 wt.% H2O. At higher water contents, solubilities are nearly constant. It can be concluded that water is not an important control of accessory phase solubility, although the water content will affect diffusivities of components in the melt, thus whether or not accessory phases will be present as restite material. The solubility behaviour in the subaluminous and peralkaline melts supports previous spectroscopic studies, which have observed differences in the coordination of high field strength elements in dry vs. wet subaluminous granitic glasses, but not for peralkaline granitic glasses. Lastly, the fact that wolframite solubility increases with increasing water content in the subaluminous melt suggests that tungsten dissolved as a hexavalent species. 相似文献
14.
Muriel Rocher Stéphane Baize Stéphane Jaillet Edward Marc Cushing Yannick Lozac&#x;h Francis Lemeille 《Comptes Rendus Geoscience》2003,335(8):701-708
Calcite samples were extracted both from the rock matrix and the superficial coating of a karstified fault plane of an underground quarry, located in the eastern border of the Paris basin. The karstification is dated as Quaternary. Analysis of mechanical calcite twinning reveals that only the calcite matrix has also undergone a compression trending WNW that can be attributed to the Mio-Pliocene alpine collision. Both coating and matrix have undergone a strike-slip regime with σ1 roughly trending north–south, that could correspond to the regional present-day state of stress, a strike-slip compression rather trending NNW, modified by local phenomena. To cite this article: M. Rocher et al., C. R. Geoscience 335 (2003). 相似文献
15.
正20141756 Chen Ruige(Mathematical College,China University of Geosciences,Beijing100083,China);Zhou Xun Numerical Simulation of Groundwater Level Fluctuation in a Coastal Confined Aquifer with Sloping Initial Groundwater Level Induced by the Tide(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(7),2013,p.1099-1104,6 illus.,16 refs.) Key words:confined water,groundwater level 相似文献
16.
正20141408 Cai Jia(Institute of Geology,Chinese Academy of Geological Sciences,Beijing100037,China);Liu Fulai Petrogenesis and Metamorphic P-T Conditions of Garnet-Spinel-Biotitebearing Paragneiss in Danangou Area,Daqingshan-Wulashan Metamorphic Complex Belt(Acta Petrologica Sinica,ISSN1000-0569,CN11-1922/P,29(7), 相似文献
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正20142386An Guoying(China Aero Geophysical Survey and Remote Sensing Center for Land and Resources,Beijing 100083,China)Application of Satellite Remote Sensing in Regional Hydrogeological Investigation:Taking Cenozoic Strata in Wenquan Sheet(1∶250 000)of Karakoram Range as an Example(Geosci- 相似文献
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正20141016An Chengbang(Key Laboratory of Western China’s Environmental Systems,Ministry of Education,Lanzhou University,Lanzhou 730000,China);Zhao Yongtao Lake Records during the Last Glacial Maximum from Xinjiang,NW China and Their Climatic Impli- 相似文献
20.
正20141538 Cao Qing(School of Earth Sciences and Engineering,Xi’an Petroleum University,Xi’an 710065,China);Zhao Jingzhou Characteristics and Significance of Fluid Inclusions from Majiagou Formation,Yichuan Huangling Area,Ordos Basin(Advances in Earth Science,ISSN1001-8166,CN62-1091/P,28(7),2013,p.819-828,7 illus.,3 tables,43 refs.) 相似文献