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71.
利用静态箱-气相色谱法对夏季(7月、8月和9月)长江河口湿地芦苇植被CO_2、CH_4和N_2O的叶面通量、茎秆扩散速率以及沉积物通量的日变化进行研究。结果显示,通过芦苇叶片排放的N_2O与CH_4的量分别为2.99μg/(m~2·h)和15.36μg/(m~2·h),CO_2则呈现白天吸收(-120.86 mg/(m~2·h))、夜间排放(69.39 mg/(m~2·h))的特点。芦苇茎秆N_2O、CH_4和CO_2平均扩散速率分别为1.96μg/h、142.45μg/h和10.69 mg/h,沉积物平均排放通量为N_2O 8.18μg/(m~2·h)、CH_41.58 mg/(m~2·h)、CO_2169.66 mg/(m~2·h)。芦苇茎秆和沉积物界面CH_4和CO_2的排放均呈现出明显的"单峰型"昼夜变化规律,其排放峰值集中在日照及温度最高的9:00至15:00。芦苇植株是影响温室气体排放变化的因素之一。芦苇植株在光合作用下吸收CO_2并促进CH_4的排放,而芦苇发达的根系及茎秆是温室气体排放的主要途径。同时,Pearson相关性分析表明温度对芦苇群落CH_4和NO2的排放影响显著,但与CO_2通量的相关性不明显。土壤氧化还原电位对3种气体的排放均有显著影响。 相似文献
72.
小清河水体和沿岸地下水中有机污染物的监测及其毒性分析 总被引:4,自引:0,他引:4
本文对小清河水体和沿岸地下水中的有机污染物进行了色-质联用分析,共检出有机污染物13类93种。并对其毒性效应进行了分析和评价。 相似文献
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对城市生活垃圾的分类回收、处理进行了探讨,对完善城市基础设施建设,改善投资环境将起到重要作用。 相似文献
75.
膜、柱串联固相萃取-高效液相色谱法测定水中多环芳烃(PAHs)的研究 总被引:5,自引:1,他引:5
建立了用膜-柱串联固相萃取(SPE)技术,甲醇和水作为流动相进行梯度洗脱,紫外和荧光检测器串联的高效液相色谱法(HPLC)分析水中EPA优先监控的16种PAHs的方法. 相似文献
76.
A pilot project to detect and forecast harmful algal blooms in the northern Gulf of Mexico 总被引:1,自引:0,他引:1
More timely access to data and information on the initiation, evolution and effects of harmful algal blooms can reduce adverse impacts on valued natural resources and human health. To achieve this in the northern Gulf of Mexico, a pilot project was initiated to develop a user-driven, end-to-end (measurements to applications) observing system. A key strategy of the project is to coordinate existing state, federal and academic programs at an unprecedented level of collaboration and partnership. Resource managers charged with protection of public health and aquatic resources require immediate notice of algal events and a forecast of when, where and what adverse effects will likely occur. Further, managers require integrated analyses and interpretations, rather than raw data, to make effective decisions. Consequently, a functional observing system must collect and transform diverse measurements into usable forecasts. Data needed to support development of forecasts will include such properties as sea surface temperature, winds, currents and waves; precipitation and freshwater flows with related discharges of sediment and nutrients; salinity, dissolved oxygen, and chlorophyll concentrations (in vivo fluorescence); and remotely-sensed spatial images of sea surface chlorophyll concentrations. These data will be provided via a mixture of discrete and autonomous in situ sensing with near real-time data telemetry, and remote sensing from space (SeaWiFS), aircraft (hyperspectral imagery) or land (high-frequency radar). With calibration across these platforms, the project will ultimately provide a 4-dimensional visualization of harmful algae events in a time frame suitable to resource managers. 相似文献
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78.
A study was carried out in a part of Palar and Cheyyar river basin to evaluate the current status of iron, manganese, zinc and atrazine concentrations, their origin and distribution in groundwater. Groundwater samples were collected during post-monsoon (March 1998 and February 1999) and pre-monsoon (June 1999) periods from 41 sampling wells distributed throughout the study area. The groundwater samples were analyzed for trace metals using AAS and atrazine using HPLC. The concentration of the trace elements in groundwater is predominant during pre-monsoon period. Distribution pattern indicates that the concentration of these elements increases from west to northeast and towards Palar river. Lower concentrations in the central part may be due to recharge of fresh water from the lakes located here. During most of the months, as there is no flow in Palar river, the concentrations of trace elements in groundwater are high. Drinking water standards indicate that Mn and Zn cross the permissible limit recommended by EPA during the pre-monsoon period. A comparison of groundwater data with trace element chemistry of rock samples shows the abundance of trace elements both in the rock and water in the order of Fe > Mn > Zn and Fe > Zn > Mn. This indicates that iron in groundwater is derived from lithogenic origin. Further, Fe, Mn and Zn have good correlation in rock samples, while it is reverse in the case of water samples, indicating the non-lithogenic origin of Mn and Zn. Atrazine (a herbicide) was not detected in any of the groundwater samples in the study area, perhaps due to low-application rate and adsorption in the soil materials. 相似文献
79.
Evaluation of Water Quality in the Chillán River (Central Chile) Using Physicochemical Parameters and a Modified Water Quality Index 总被引:4,自引:0,他引:4
Debels P Figueroa R Urrutia R Barra R Niell X 《Environmental monitoring and assessment》2005,110(1-3):301-322
The Chillán River in Central Chile plays a fundamental role in local society, as a source of irrigation and drinking water,
and as a sink for urban wastewater. In order to characterize the spatial and temporal variability of surface water quality
in the watershed, a Water Quality Index (WQI) was calculated from nine physicochemical parameters, periodically measured at
18 sampling sites (January–November 2000). The results indicated a good water quality in the upper and middle parts of the
watershed. Downstream of the City of Chillán, water quality conditions were critical during the dry season, mainly due to
the effects of the urban wastewater discharge. On the basis of the results from a Principal Component Analysis (PCA), modifications
were introduced into the original WQI to reduce the costs associated with its implementation. WQIDIR2 and WQIDIR, which are both based on a laboratory analysis (Chemical Oxygen Demand) and three (pH, temperature and conductivity), respectively,
four field measurements (pH, temperature, conductivity and Dissolved Oxygen), adequately reproduce the most important spatial
and temporal variations observed with the original index. They are proposed as useful tools for monitoring global water quality
trends in this and other, similar agricultural watersheds in the Chilean Central Valley. Possibilities and limitations for
the application of the used methodology to watersheds in other parts of the world are discussed. 相似文献
80.