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71.
72.
碱消解-高效液相色谱-电感耦合等离子体质谱法测定生物样品中的甲基汞和乙基汞 总被引:7,自引:2,他引:5
建立了碱消解-高效液相色谱-电感耦合等离子体质谱联用系统测定生物样品中甲基汞(MeHg)与乙基汞(EtHg)的分析方法。为提高灵敏度,选用微流量的PFA雾化器,在优化的检测条件下,MeHg及EtHg检出限可达到0.036μg/L和0.03μg/L;线性范围达到4个数量级,两条工作曲线线性相关系数为1。对1.78μg/L MeHg、1.65μg/L EtHg的混合标准溶液重复测定7次,色谱峰面积的相对标准偏差(RSD)分别为1.79%和1.44%。对标准物质BCR 464(金枪鱼)的分析结果表明,测定值与标准值基本吻合,但略低于标准值;甲基汞和乙基汞的加标回收率分别为85.9%和84.5%。高效液相色谱与质谱联用技术的高灵敏度和低检出限能够满足生物样品中汞形态定量分析的要求。 相似文献
73.
Delineation of groundwater protection zones by the backward particle tracking method: theoretical background and GIS-based stochastic analysis 总被引:1,自引:0,他引:1
Konstadinos N. Moutsopoulos Alexandra Gemitzi Vassilios A. Tsihrintzis 《Environmental Geology》2008,54(5):1081-1090
The backward particle tracking method, an effective and powerful tool that can be used to delineate groundwater protection
zones, is presented. The theoretical background and insights on the applicability of this method are provided. Moreover, the
present work enriches the backward particle tracking method with an uncertainty analysis concerning the porosity values, applying
a Monte Carlo (MC) approach, coupled with the use of geographical information systems (GIS). As an application example, a
wellfield in the Komotini area, Greece, is investigated. The present study may serve as a potential guideline for wellfield
delineation, particularly in areas like Greece where lack of data related to the hydrogeological system is often a problem. 相似文献
74.
L. Moreno J. J. Durán M. A. Casermeiro J. R. Quintana Ma A. Fernández 《Environmental Geology》2008,54(3):465-477
Over a period of 4 years and 4 months, the geopurification installations at Dehesas de Guadix (Granada, Spain) were monitored
to determine the impact on soil and groundwater of the controlled discharge of urban wastewater, and also to identify the
best indicators of the entry of the recharged water into the aquifer. The installations are located in an area where the climate
is Mediterranean sub-arid, with an average precipitation of less than 287 mm/year, and a rate of evapotranspiration that is
almost three times greater. The system was controlled by determining the balance of majority nutrients and boron in the soil
and in the groundwater, both at the points affected directly by the wastewater discharge and at others. The quantity of mass
discharged was relatively large (COD 14,656 g/m2, NO3 85 g/m2, NO2 4 g/m2, NH4 2,425 g/m2, PO4 1,143 g/m2, K 1,531 g/m2, B 63 g/m2). It was observed that the elimination of nutrients within the soil (COD 97.5%, PO4 94.4%, K 59.17%, N
total 18.8%, B 12.69%) was very efficient except for the nitrogen, which nevertheless did not reach the groundwater, as it was
eliminated at deep levels of the unsaturated zone. Only 12.69% of the boron was removed, and appreciable, increasing amounts
of this element did reach the groundwater. Unexpectedly, none of the majority nutrients behaved as a reliable indicator of
the impact on groundwater; despite this, the boron and the bicarbonate did clearly reflect the arrival of the recharged water,
and are proposed as the best indicators. 相似文献
75.
The Krishni–Yamuna interstream area is a micro-watershed in the Central Ganga Plain and a highly fertile track of Western
Uttar Pradesh. The Sugarcane and wheat are the major crops of the area. Aquifers of Quaternary age form the major source of
Irrigation and municipal water supplies. A detailed hydrogeological investigation was carried out in the study area with an
objective to assess aquifer framework, groundwater quality and its resource potential. The hydrogeological cross section reveals
occurrence of alternate layers of clay and sand. Aquifer broadly behaves as a single bodied aquifer down to the depth of 100 m bgl
(metre below ground level) as the clay layers laterally pinch out. The depth to water in the area varies between 5 and 16.5 m bgl.
The general groundwater flow direction is from NE to SW with few local variations. An attempt has been made to evaluate groundwater
resources of the area. The water budget method focuses on the various components contributing to groundwater flow and groundwater
storage changes. Changes in ground water storage can be attributed to rainfall recharge, irrigation return flow and ground
water inflow to the basin minus baseflow (ground water discharge to streams or springs), evapotranspiration from ground water,
pumping and ground water outflow from the basin. The recharge is obtained in the study area using Water table fluctuation
and Tritium methods. The results of water balance study show that the total recharge in to the interstream region is of the
order of 185.25 million m3 and discharge from the study area is of the order of 203.24 million m3, leaving a deficit balance of −17.99 million m3. Therefore, the present status of groundwater development in the present study area has acquired the declining trend. Thus,
the hydrogeological analysis and water balance studies shows that the groundwater development has attained a critical state
in the region. 相似文献
76.
This paper presents an example of application of the double solid reactant method (DSRM) of Accornero and Marini (Environmental
Geology, 2007a), an effective way for modeling the fate of several dissolved trace elements during water–rock interaction. The EQ3/6 software
package was used for simulating the irreversible water–rock mass transfer accompanying the generation of the groundwaters
of the Porto Plain shallow aquifer, starting from a degassed diluted crateric steam condensate. Reaction path modeling was
performed in reaction progress mode and under closed-system conditions. The simulations assumed: (1) bulk dissolution (i.e.,
without any constraint on the kinetics of dissolution/precipitation reactions) of a single solid phase, a leucite-latitic
glass, and (2) precipitation of amorphous silica, barite, alunite, jarosite, anhydrite, kaolinite, a solid mixture of smectites,
fluorite, a solid mixture of hydroxides, illite-K, a solid mixture of saponites, a solid mixture of trigonal carbonates and
a solid mixture of orthorhombic carbonates. Analytical concentrations of major chemical elements and several trace elements
(Cr, Mn, Fe, Ni, Cu, Zn, As, Sr and Ba) in groundwaters were satisfactorily reproduced. In addition to these simulations,
similar runs for a rhyolite, a latite and a trachyte permitted to calculate major oxide contents for the authigenic paragenesis
which are comparable, to a first approximation, with the corresponding data measured for local altered rocks belonging to
the silicic, advanced argillic and intermediate argillic alteration facies. The important role played by both the solid mixture
of trigonal carbonates as sequestrator of Mn, Zn, Cu and Ni and the solid mixture of orthorhombic carbonates as scavenger
of Sr and Ba is emphasized.
相似文献
Luigi Marini (Corresponding author)Email: |
77.
Mapping ambivalence: Exploring the geographies of community change and rails-to-trails development using photo-based Q method and PPGIS 总被引:5,自引:0,他引:5
As the literature on trail development suggests, recreational trail projects can generate conflicts and controversies, particularly when built on abandoned rail corridors through developed areas. These conflicts are often understood as “not in my back yard” (NIMBY) reactions, suggesting a spatial proximity to conflict which increases as one draws closer to the proposed trail. This research seeks to understand local residents’ perceptions and reactions to recreational trail development in the City of Delaware (Ohio, USA). It addresses two spatially infused questions: Does the potential for conflict related to trail development increase as people live closer to a potential trail (the NIMBY factor)? Can important qualitative factors about favorable and unfavorable land uses including potential recreational trail sites be defined using a participatory methodology and then represented in GIS? The study used a mixed-method approach to collect and analyze qualitative data from a group of local residents. Each participant was interviewed and asked to sort 19 pictures related to trail development. After each of the sorts, participants were asked to explain why they ranked the pictures the way they did. Results of the picture sorts were then analyzed using Q method and mapped with GIS. The results show that spatial proximity matters in the context of trail development and potential NIMBY reactions to trails. Significant differences were found in the picture sorts that reveal the importance of proximity and location, although in a manner contrary to the assumptions in the writings on rails-to-trails. Through combining qualitative methods, Q analysis and PPGIS analysis, the research shows that qualitative place-based studies are capable of generating insights about the complexities of situated geographic change such as recreational trail development. 相似文献
78.
V. A. Lebedev S. N. Bubnov O. Z. Dudauri G. T. Vashakidze 《Stratigraphy and Geological Correlation》2008,16(2):204-224
Isotopic-geochronological study of the Pliocene magmatic activity in western part of the Dzhavakheti Highland (northwestern region of the Lesser Caucasus) is carried out. The results obtained imply that the Pliocene magmatic activity lasted in this part of the highland approximately 2 million years from 3.75 to 1.75–1.55 Ma. As is established, the studied volcanic rocks correspond in composition mostly to K-Na subalkaline and more abundant normal basalts. Time constraints of main phases in development of basic volcanism within the study region are figured out. We assume that individual pulses of silicic to moderately silicic volcanism presumably took place in the Dzhavakheti Highland about 3.2 and 2.5 Ma ago. 相似文献
79.