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气相色谱-质谱法同时测定河流沉积物中多环芳烃和有机氯农药 总被引：4，自引：1，他引：3
建立了用加速溶剂萃取,气相色谱-质谱法同时测定河流沉积物中16种多环芳烃和19种有机氯农药的分析方法,优化了萃取溶剂、萃取温度和时间、凝胶渗透色谱收集时间、固相萃取洗脱溶剂和洗脱体积等条件。16种多环芳烃的方法检出限在0.15~0.59 ng/g,加标回收率为82%~102%,相对标准偏差(RSD,n=5)为1.1%~4.5%。19种有机氯农药的方法检出限在0.14~2.23 ng/g,加标回收率为71%~108%,相对标准偏差(RSD,n=5)为1.0%~4.5%。实际样品的测定结果表明,该方法分离效果较好,能够满足沉积物样品中多环芳烃和有机氯农药的分析要求。 相似文献
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气相色谱法测定地下水多环芳烃准确度的保证措施 总被引：3，自引：0，他引：3
针对环境中常见且对人体危害极大的USEPA优先控制污染物16种多环芳烃(PAHs)在地下水中的监测方法进行了研究,主要从影响方法准确度的空白溶剂的选择、标准样品测定、基质加标回收率方面进行了实验研究,利用数理统计的t 检验进行显著性检验,并对研究区水中的多环芳烃进行了测定。结果表明,该方法宜选用市售纯净水做空白溶剂,基质加标回收率在71 5%~99 7%范围内,标准样品测定的相对误差在1 0%~17 2%;经系统误差检验确定本方法不存在系统误差,可以达到测定地下水中多环芳烃的目的。实际样品的测定结果说明煤矸石中的多环芳烃随降水淋滤以及酸性矿坑排水进入地下水和地表水的可能性是存在的,其迁移转化机理需进一步深入研究。 相似文献
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气相色谱-质谱联用法测定土壤中16种多环芳烃 总被引：1，自引：0，他引：1
应用加速溶剂萃取气相色谱-质谱联用法测定土壤中16种多环芳烃。确定了二氯甲烷-丙酮(体积比1:1)作为提取溶剂,方法检出限为0.10～3.90ng/g,加标回收率为72.6%～123.5%。方法检出限较低,精密度好,适用于土壤样品中多环芳烃的分析。 相似文献
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荧光-紫外检测器高效液相色谱法检测地下水中16种多环芳烃 总被引：1，自引：1，他引：0
应用荧光-紫外检测器联用的高效液相色谱法分析地下水中16种多环芳烃。对高效液相色谱条件进行优化,建立了分析方法,并用于实际水样分析。在较佳的实验条件下,加标回收率为86.3%～105%,方法精密度(RSD,n=7)为0.39%～2.55%,检出限为0.001～0.010μg/L。分析16种PAHs仅用20min,比EPA8310方法中采用的液相色谱法缩短了17min。方法灵简便、准确,灵敏度高,分析时间短,适用于大批量地下水中痕量多环芳烃的分析。 相似文献
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选取某化工场地作为研究对象,采集不同深度的原状土壤样品和原状地下水样品,对土壤样品和地下水样品的16种优控多环芳烃进行定量分析,研究不同种类的多环芳烃在包气带和饱和带中的分布特征和迁移规律.研究表明,在平面上,多环芳烃在土壤和地下水中的污染高值区与生产车间分布基本一致;在垂向上,土壤中的16种多环芳烃集中分布在杂填土层,低环和中环的多环芳烃更易向下迁移,并在黏土层产生一定的富集,仅有最低环的萘通过包气带迁移至饱和层中,饱和层中的萘一部分在地下水中扩散,一部分仍继续垂向迁移至更深层的土壤中.通过特定分子间的浓度比值,初步判定场地土壤中的多环芳烃来源为原油的不完全燃烧. 相似文献
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河流沉积物多环芳烃标准样品的制备与定值 总被引：3，自引：1，他引：2
多环芳烃环境标准样品是保证多环芳烃环境监测和污染调查数据可靠性以及不同实验室间分析数据可比性必不可少的计量工具。美国NIST、欧盟IRMM、英国LGC等研究机构已有沉积物多环芳烃环境标准样品,但浓度水平大部分集中在mg/kg浓度水平,与我国当前的污染水平存在一定差距,难以满足痕量分析(μg/kg)质量保证与质量控制的要求。而我国受天然基体标准样品制备技术和定值分析技术的制约,尚没有研制沉积物多环芳烃环境标准样品。本文研制了适合我国多环芳烃环境监测和科学研究需要的河流沉积物标准样品。沉积物样品采集自松花江哈尔滨段流域,经过自然阴干、研磨、筛分、混匀和灭菌等加工处理,分层随机抽取15瓶样品对16种多环芳烃进行均匀性研究,结果表明样品均匀性良好。在30℃避光保存条件下,采用线性模型进行稳定性研究,标准样品在16个月稳定性检验期间未发现不稳定变化趋势。11家实验室对该河流沉积物标准样品采用气相色谱-质谱法和液相色谱法进行联合定值,经统计分析处理评定出14种多环芳烃的标准值和不确定度,并给出2种多环芳烃的参考值,特性量值在6.9~158 μg/kg之间,不确定度在1.5~25 μg/kg之间,可以满足多环芳烃痕量分析质量保证与质量控制的要求。该标准样品被批准为国家标准样品,填补了国内此类标准样品和标准物质空白,已成功应用于土壤和沉积物样品中多环芳烃的监测,可为进一步开展有机污染物环境基体标准样品研制提供参考和借鉴。 相似文献
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珠江广州河段重污染沉积物中多环芳烃赋存状态初步研究 总被引：8，自引：2，他引：6
对珠江广州河段重污染沉积物进行粒度分级 (>500 μm、500～ 220 μm、220～ 63 μm、63～ 22 μm和 < 22 μm),每个粒级的样品进行重液分离,收集轻组分 (有机质 )和重组分 (主要为无机矿物及无定型有机质 ).在显微镜下对沉积物中不同粒径轻重组分的吸附剂进行鉴定,对其中的多环芳烃进行定量分析,结果表明,白鹅潭样品中有机质占总质量的 9.10%,富集了 81.55%的多环芳烃,无机矿物和无定型有机质占 90.92%,富集了 18.45%的多环芳烃;黄埔样品中有机质占总质量的 8.95%,富集了 56.50%的多环芳烃,无机矿物和无定型有机质占 91.15%,富集了 43.50%的多环芳烃.轻组分中的有机吸附剂对多环芳烃的富集能力比重组分无机矿物和无定型有机质高 1～ 2个数量级,轻组分有机吸附剂中焦碳和碳黑富集能力较高,植物碎屑较低.总有机碳和碳黑的含量与多环芳烃的富集能力没有明显的相关性. 相似文献
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High pressure deformation in two-phase aggregates 总被引：1，自引：0，他引：1
We investigate the rheological behavior of multi-phase aggregates at high pressure and high temperature. Using synchrotron X-ray radiation as the probing tool, we are able to quantify the stress state of individual phases within the aggregates. This method provides fundamental information in interpreting the behavior of two phase/multi-phase mixtures, which contribute to our understanding of the deformation process at deep earth conditions. We choose MgAl2O4 spinel and MgO periclase as our model materials. Mixtures of various volume proportions were deformed in a multi-anvil high pressure deformation apparatus at pressure of 5 GPa and elevated temperatures. Stress is determined from X-ray diffraction, providing a measure of stress in each individual phase of the mixture in situ during the deformation. Macroscopic strain is determined from X-ray imaging. We compare the steady state strength of various mixtures at 1000 °C and 800 °C and at the strain rate in the range of 1.8 to 8.8 × 10− 5 s− 1. Our data indicate that the weak phase (MgO) is responsible for most of the accumulated strains while the strong phase (spinel) is supporting most of the stress when the volume proportion is 75% spinel and 25% MgO. The intermediate compositions (40/60) are much weaker than either of the end members, while the grain sizes for the intermediate compositions (submicrons) are much smaller than the end members (5–10 μm). We conclude that a change in flow mechanism resulting from these smaller grains is responsible for the low strength of the intermediate composition mixtures. This study demonstrates an approach of using synchrotron X-rays to study the deformation behaviors of multi-phase aggregates at high pressure and high temperature. 相似文献
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Based on the operational standard indices, the prediction skills of the Western-Pacific Subtropical High (WPSH) and South-Asian High (SAH) using 2019 real-time forecasts derived from the Global Ensemble Prediction System of GRAPES (GRAPES-GEPS) in China Meteorological Administration (CMA) Numerical Prediction Center were evaluated and the effects of different ensemble approaches on the prediction skills of WPSH and SAH indices were further investigated in this study. The results show that for WPSH, the GRAPES-GEPS has its highest prediction skill for the ridge line index, considerably high skill for the intensity and area indices, but relatively low skill for the western boundary index, and for SAH, it has comparatively high skill for the intensity and center latitude indices, but relatively lower skill for the center longitude index. Prediction errors of the GRAPES-GEPS for the WPSH forecasts are featured by the weaker intensity and area and the more eastward center position, compared with the observation, which can be effectively reduced by employing the maximum/minimum approach from ensemble members, relative to the ensemble mean approach. By direct comparison, prediction errors of the GRAPES-GEPS for the SAH forecasts are featured by the weaker intensity and the more southward center position, which tends to be slightly reduced using the ensemble mean approach. Finally, for the extreme forecast, the maximum approach provides superior performance for both WPSH and SAH than the ensemble mean approach, which can be validated in terms of the two extreme cases. These results clearly indicate that the maximum approach could better improve the GRAPES-GEPS performance for the extreme forecasting of the two primary circulation patterns than the traditional ensemble mean approach. 相似文献
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S. K. Sasamal 《Journal of Earth System Science》1990,99(3):367-381
Bay of Bengal is well known for less saline waters in the surface layer of northern Indian Ocean. High saline waters of the
Bay are considered as an influx from the Arabian Sea within a depth range of 200 to 900 m. Some of the recent observations
in the western Bay of Bengal have shown salinity values higher than those reported earlier (35-2 × 10−3). Such values are explained on the basis of regional climatology suggesting their local formation on the shallow continental
shelf during pre-monsoon months and their subsequent distribution along the coast. 相似文献
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高密度电阻率法由常规电法演化而来,其电极排列类型多,应用范围广。本文以北京地区的地下采空勘查探测为例,论述了高密度电阻率法的测线布置、电极排列,到数据处理、图像解释等技术方法。通过实地钻孔验证,说明探测结果准确,为采空区评价提供了可信的基础数据。 相似文献
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高密度电阻率法具有一次布线、连续测量、数据采集量大、地质信息丰富,成果可信度高等优点,通过控制测量电极的距离来提高分辨率,加大有效勘察深度,提高观测精度,可有效地解决工程勘察中遇到的各种地质问题,相对其他物探方法具有无法比拟的优势。 相似文献
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高频燃烧-红外吸收光谱法测定钼矿石和镍矿石中的高含量硫 总被引：3，自引：3，他引：0
高频燃烧-红外吸收法用于分析矿石中低含量硫的测定结果较为准确,但对于高含量的硫,分析结果的准确度不高。本文采用高频燃烧-红外碳硫分析仪测定钼矿石和镍矿石中的高含量硫,选择纯铁屑和钨粒作助熔剂,高温燃烧分解样品,通过实验优化了样品称样量、助熔剂用量、仪器分析时间等测定条件。用国家标准物质进行验证,方法精密度(RSD,n=9)小于1%,加标回收率为96.0%～101.9%;与传统的硫酸钡重量法进行比对试验,测定值的相对误差小于2%。针对不同的矿石样品,研究了实际样品与标准物质的基体匹配问题,消除了基体效应的影响,对于钼矿石和镍矿石样品中含量在1%～35%范围内的硫,均能够准确测定,解决了钼矿石和镍矿石中高含量硫的快速、准确测定问题。 相似文献
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ABSTRACT The High Himalayan Crystallines (HHC) of SE Zanskar consist of biotite paragneisses, of orthogneisses that derive from early-Palaeozoic granitoids, of minor metabasics and of post-metamorphic leucogranites of Miocene age. Two main metamorphic events have been documented in the HHC. The first event occurred at P= 12.0 ± 0.5 kbar and T= 750 ± 50° C in rare metabasics intruded by early-Palaeozoic granitoids. In the biotite paragneisses, thermobarometric estimates of the first event point to comparable T at P 4–5 kbar lower. The first event is followed by a pervasive syn-tectonic crystallization characterized by lower P and T. On the basis of the cooling ages of the metamorphic minerals and on the geological evidence, the second event is referred to the Tertiary Himalayan crystallization. Further petrological and geochronological studies are necessary to prove whether a few mineral relics ascribed to the first event define a polyphase Himalayan evolution or if they record the incomplete obliteration of an older history during the Himalayan event. The HHC of SE Zanskar show a decrease in metamorphic grade from the middle structural levels upward, close to the Kade unit, and downward, close to the Lesser Himalaya (from sillimanite-K-feldspar-biotite-bearing assemblages to kyanite-staurolite-muscovite-bearing assemblages). This metamorphic zonation is probably a consequence of the polyphase history of intracontinental thrusts and of the tectonic emplacement of hot crustal slabs within shallower and colder thrust sheets at relatively late stages of the continental collision between India and Eurasia. 相似文献
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Groundwater recharge and chemical evolution in the southern High Plains of Texas, USA 总被引：3，自引：1，他引：3
The unconfined High Plains (Ogallala) aquifer is the largest aquifer in the USA and the primary water supply for the semiarid
southern High Plains of Texas and New Mexico. Analyses of water and soils northeast of Amarillo, Texas, together with data
from other regional studies, indicate that processes during recharge control the composition of unconfined groundwater in
the northern half of the southern High Plains. Solute and isotopic data are consistent with a sequence of episodic precipitation,
concentration of solutes in upland soils by evapotranspiration, runoff, and infiltration beneath playas and ditches (modified
locally by return flow of wastewater and irrigation tailwater). Plausible reactions during recharge include oxidation of organic
matter, dissolution and exsolution of CO2, dissolution of CaCO3, silicate weathering, and cation exchange. Si and 14C data suggest leakage from perched aquifers to the High Plains aquifer. Plausible mass-balance models for the High Plains
aquifer include scenarios of flow with leakage but not reactions, flow with reactions but not leakage, and flow with neither
reactions nor leakage. Mechanisms of recharge and chemical evolution delineated in this study agree with those noted for other
aquifers in the south-central and southwestern USA.
Electronic Publication 相似文献