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631.
我国正在起草《土壤污染防治法》,这将为我国土壤、场地污染防治管理提供基本法律依据,并逐步建成完善的污染场地管理的法律制度体系。其中,监管体系、资金体系和责任体系是污染场地管理体系中的3大重要方面。美国、日本等发达国家和我国台湾地区在各自污染场地管理法律制度体系中,均规定了明确的监管主体,采用了多样化的监管手段,建立了可持续的污染场地专项基金,确定了明晰的责任判定和追究原则,为我国场地污染防治立法和制度设计中监管体系、资金体系和责任体系的建设提供了宝贵的借鉴。  相似文献   
632.
城市污水管网污染物沉积与冲刷释放规律研究   总被引:1,自引:0,他引:1  
为明确城市污水管网中污染物沉积、冲刷释放及微生物降解作用对有机物去除的贡献,以管网中城市污水为研究对象,通过建立有沉积与无沉积的模拟管道,在首次冲刷的理论基础上得到管道污染物沉积释放计算模型,进而研究了不同流量下有机污染物的沉积与冲刷释放规律,并对不同流量下进出水的粒径分布及颗粒组成进行分析。结果表明,在管道6 h水力循环条件下,当流速为0.32 m/s时,污水中有机物变化以沉积贡献为主;当流速增加为管网最小设计流速0.6 m/s时,污染物沉积现象得到显著改善,冲刷释放效应增强;当流速进一步增加为0.9 m/s时,冲刷释放成为主要作用,生物降解作用微弱。  相似文献   
633.
At present,continuous observation data for atmospheric nitrous oxide(N_2O) concentrations are still lacking,especially in east Antarctica.In this paper,nitrous oxide background concentrations were measured at Zhongshan Station(69°22′25″S,76°22′14″E),east Antarctica during the period of 2008–2012,and their interannual and seasonal characteristics were analyzed and discussed.The mean N_2O concentration was 321.9 n L/L with the range of 320.5–324.8 n L/L during the five years,and it has been increasing at a rate of 0.29% year-1.Atmospheric N_2O concentrations showed a strong seasonal fluctuation during these five years.The concentrations appeared to follow a downtrend from spring to autumn,and then increased in winter.Generally the highest concentrations occurred in spring.This trend was very similar to that observed at other global observation sites.The overall N_2O concentration at the selected global sites showed an increasing annual trend,and the mean N_2O concentration in the Northern Hemisphere was slightly higher than that in the Southern Hemisphere.Our result could be representative of atmospheric N_2O background levels at the global scale.This study provided valuable data for atmospheric N_2O concentrations in east Antarctica,which is important to study on the relationships between N2 O emissions and climate change.  相似文献   
634.
以重庆市涪陵区为例,在了解区域大气环境功能区划及区域大气环境质量现状的前提下,采用A-P值法,对涪陵区十三五期间大气环境容量进行研究,并对辖区内的污染负荷进行预测,在此基础上,对大气污染总量控制指标进行分配.研究结果表明,在涪陵区化工园区的二氧化硫排放量已达到或超过总量控制指标,需要制定削减计划,新兴工业园区污染物排放量虽远小于总量控制指标,但根据城市发展规划需进行结构优化与合理布局.  相似文献   
635.
The National Weather Service (NWS) forecasts floods at approximately 3,600 locations across the United States (U.S.). However, the river network, as defined by the 1:100,000 scale National Hydrography Dataset‐Plus (NHDPlus) dataset, consists of 2.7 million river segments. Through the National Flood Interoperability Experiment, a continental scale streamflow simulation and forecast system was implemented and continuously operated through the summer of 2015. This system leveraged the WRF‐Hydro framework, initialized on a 3‐km grid, the Routing Application for the Parallel Computation of Discharge river routing model, operating on the NHDPlus, and real‐time atmospheric forcing to continuously forecast streamflow. Although this system produced forecasts, this paper presents a study of the three‐month nowcast to demonstrate the capacity to seamlessly predict reach scale streamflow at the continental scale. In addition, this paper evaluates the impact of reservoirs, through a case study in Texas. Validation of the uncalibrated model using observed hourly streamflow at 5,701 U.S. Geological Survey gages shows 26% demonstrate PBias ≤ |25%|, 11% demonstrate Nash‐Sutcliffe Efficiency (NSE) ≥ 0.25, and 6% demonstrate both PBias ≤ |25%| and NSE ≥ 0.25. When evaluating the impact of reservoirs, the analysis shows when reservoirs are included, NSE ≥ 0.25 for 56% of the gages downstream while NSE ≥ 0.25 for 11% when they are not. The results presented here provide a benchmark for the evolving hydrology program within the NWS and supports their efforts to develop a reach scale flood forecasting system for the country.  相似文献   
636.
Currently, organophosphate pesticides (OPs) are widely used for agriculture in China and around the world. A few epidemiological studies have examined the association between exposure to OPs and children’s health, but these studies reported inconsistent results. In view of the limitations of testing techniques and the intrinsic incompleteness of scientific evidence from current studies, we have considered some issues which may be interpreted and handled with caution.  相似文献   
637.
638.
利用玻壳厂铅尘生产三盐基硫酸铅的研究   总被引:2,自引:0,他引:2  
介绍了由玻壳厂铅尘生产三盐基硫酸铅的原理,工艺流程及操作条件,该法充分 铅尘的有效成份,产品质量好,工艺简单易行,无二次污染,经济效益显著,为充分利用含铅废为和减少污染提供了一条有效途径。  相似文献   
639.
High production cost is the key issue of biodiesel industry nowadays. To low down the cost, using low-quality lipids feedstock is the most effective way. Two-step process is vastly applied to deal with those low-quality lipids to produce biodiesel. However, environmentally unfriendly wastes are formed during the process. Here we use calcium oxide residue and wastewater from biodiesel production to produce nanostructured calcium carbonate (CaCO3) by carbonation at ambient temperature. The results show that CaCO3 is hydrophobic and has broccoli-like morphology. It is made up of many uniform nano-rods, and each rod is composed of smaller particles with diameters about 50 nm. The idea of wastes utilization could make the biodiesel production process environmentally friendly, and the income of the produced CaCO3 could further low down the cost of biodiesel production.  相似文献   
640.
Organic phosphorus (P) fractions in surface sediments from a large shallow, eutrophic Lake Taihu, China, were extracted with 0.1 M NaOH after pre-treatment of the sediments with a solution composed of 0.1 M EDTA and 2% (w/v) Na2S2O4. Composition of organic P in the extracts was then characterized by 31P nuclear magnetic resonance spectroscopy (31P NMR). Several P species, including phosphonates, orthophosphate, orthophosphate monoesters, phospholipids, DNA, pyrophosphate and polyphosphate, were detected in the NaOH extracts. The proportion of extracted organic P to total P in sediments was negatively correlated with total P in the water column, as were the proportions for orthophosphate monoesters and DNA. This implies that the majority of organic P in surface sediments is likely stabilized in some way, and does not directly contribute to the internal loading of P from sediments.  相似文献   
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