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881.
采用包括填料表面微观特征、元素构成、吸附性能、微生物附着生长性、经济性等因素的填料性能评价方法,对处理含油地表水的潜流湿地填料进行评价与筛选.静态吸附试验表明,各种填料对磷的吸附能力为炉渣>陶粒>沸石>砾石>砖块>卵石,对石油类的吸附能力为炉渣>陶粒>砖块>沸石>砾石>卵石;动态吸附试验表明,各种填料床对石油类的去除效果为炉渣床>砾石床>湖泊底泥床;放置在污染水体中的填料表面微生物总数和烃降解菌数量为砖块>沸石>砾石,陶粒和炉渣>卵石.根据上述评价结果,选择总体性能较好的砾石、炉渣、砖块和沸石作为潜流湿地现场试验系统的填料.  相似文献   
882.
Water pollution such as green algae blooms and eutrophication in freshwater fatally influences both water quality and human society. Water quality issues in the 4 major rivers in Korea, including the Nakdong, have recently become a major concern. For this reason, it is essential to monitor water quality parameters (WQPs) that have a widespread characteristic to ensure maintenance of an effective water management system. The possibility of utilizing remote sensing technology for monitoring water quality on a regional scale has been recently investigated. The main objective of this study is to evaluate potential applications of the Landsat 8 Operational Land Imager (OLI) for estimating water quality in the Nakdong River, Korea. Correlations between Landsat 8 bands and in situ measurements are determined, and water quality models are established for estimating suspended solids (SS), total nitrogen (TN), chlorophyll-a (Chl-a), and total phosphorus (TP). The results demonstrate that WQPs correlated well with band reflectance values from Landsat 8. Band 5 was reasonably correlated with all WQPs, particularly with SS (R?=??0.74) and Chl-a (R?=??0.71). This study constructed multiple regression equations for WQPs based on correlation analysis through band combination and band ratio. The spatial distribution of WQPs in the Nakdong River on October 27, 2013 and May 16, 2014 indicate that the river was nearly eutrophic from human activities. Based on the results, the Landsat 8 OLI may be an appropriate data for estimating and monitoring water quality parameters on a regional scale. However, further validation is required to support the findings of this study.  相似文献   
883.
国家环境监测综合数据空间元数据库系统的设计   总被引:1,自引:0,他引:1  
利用元数据对数据进行描述、查询检索和管理可以满足数据生产者对数据的管理和维护 ,并能使用户实现快速查询。全国环境质量元数据库系统的建立是为了规范环境质量数据信息 ,使环境质量信息共享成为可能 ,使二十年来积淀下来的全国环境质量监测信息成为可在国内进行共享的宝贵资料 ,唤起广大人民群众对环境问题的普遍关注 ,共同投身于环境保护事业 ,改善我们的生存环境  相似文献   
884.
For groundwater conservation and management, it is important to accurately assess groundwater pollution vulnerability. This study proposed an integrated model using ridge regression and a genetic algorithm (GA) to effectively select the major hydro-geological parameters influencing groundwater pollution vulnerability in an aquifer. The GA-Ridge regression method determined that depth to water, net recharge, topography, and the impact of vadose zone media were the hydro-geological parameters that influenced trichloroethene pollution vulnerability in a Korean aquifer. When using these selected hydro-geological parameters, the accuracy was improved for various statistical nonlinear and artificial intelligence (AI) techniques, such as multinomial logistic regression, decision trees, artificial neural networks, and case-based reasoning. These results provide a proof of concept that the GA-Ridge regression is effective at determining influential hydro-geological parameters for the pollution vulnerability of an aquifer, and in turn, improves the AI performance in assessing groundwater pollution vulnerability.  相似文献   
885.
A new method has been developed to determine heptachlor and its metabolites heptachlor-exo-epoxide and heptachlor-endo-epoxide in pork. The pork samples were extracted with acetone–n-hexane (2:8, V:V) and cleaned up by gel permeation chromatography and florisil solid-phase extraction cartridge. The extract was then determined by gas chromatography equipped with electron capture detector (GC-ECD), followed by validation using gas chromatography–mass spectrometry (GC–MS) with negative chemical ionization. Linearity of calibration curves ranged from 0.01 to 0.5 mg L?1, with correlation coefficients of more than 0.9980 for GC-ECD and GC–MS, respectively. At spiked concentrations of 0.01, 0.05, and 0.1 mg kg?1, the average recovery and relative standard deviation values were 87.1–102.2 and 4.0–11.3 %, respectively. The limit of quantification for each analyte was 0.01 mg kg?1, which satisfied the current maximum residue limit permitted in pork. Our results showed that the method developed was successfully used to determine heptachlor and heptachlor epoxide residues in real pork samples.  相似文献   
886.
Atmospheric corrections for multi-temporal optical satellite images are necessary, especially in change detection analyses, such as normalized difference vegetation index (NDVI) rationing. Abrupt change detection analysis using remote-sensing techniques requires radiometric congruity and atmospheric correction to monitor terrestrial surfaces over time. Two atmospheric correction methods were used for this study: relative radiometric normalization and the simplified method for atmospheric correction (SMAC) in the solar spectrum. A multi-temporal data set consisting of two sets of Landsat images from the period between 1991 and 2002 of Penang Island, Malaysia, was used to compare NDVI maps, which were generated using the proposed atmospheric correction methods. Land surface temperature (LST) was retrieved using ATCOR3_T in PCI Geomatica 10.1 image processing software. Linear regression analysis was utilized to analyze the relationship between NDVI and LST. This study reveals that both of the proposed atmospheric correction methods yielded high accuracy through examination of the linear correlation coefficients. To check for the accuracy of the equation obtained through linear regression analysis for every single satellite image, 20 points were randomly chosen. The results showed that the SMAC method yielded a constant value (in terms of error) to predict the NDVI value from linear regression analysis-derived equation. The errors (average) from both proposed atmospheric correction methods were less than 10%.  相似文献   
887.
A comprehensive monitoring program was conducted during 2005-2007 to investigate seasonal variations of hydrologic stability and water quality in the Yeongsan Reservoir (YSR), located at the downstream end of the Yeongsan River, Korea. A principal component analysis (PCA) was performed to identify factors dominating the seasonal water quality variation from a large suite of measured data--11 physico-chemical parameters from 48 sampling sites. The results showed that three principal components explained approximately 62% of spatio-seasonal water quality variation, which are related to stratifications, pollutant loadings and resultant eutrophication, and the advective mixing process during the episodic rainfall-runoff events. A comparison was then made between YSR and an upstream freshwater reservoir (Damyang Reservoir, DYR) in the same river basin during an autumn season. It was found that the saline stratification and pollutant input from the upstream contributed to greater concentrations of nutrients and organic matter in YSR compared to DYR. In YSR, saline stratification in combination with thermal stratification was a dominant cause of the longer period (for two consecutive seasons) of hypoxic conditions at the reservoir bottom. The results presented here will help better understand the season- and geography-dependent characteristics of reservoir water quality in Asian Monsoon climate regions such as Korea.  相似文献   
888.
This paper highlights the levels of anions (nitrate, nitrite, sulfate, bromide, chloride, and fluoride) and cations (potassium, sodium, magnesium, and calcium) in selected springs and groundwater sources in the urban-west region of Zanzibar Island. The levels of total dissolved solids (TDS) and sodium adsorption ratio (SAR) were also studied. Thirty water samples were collected in December 2012 from various types of water sources, which included closed hand-dug wells (CHDW), open hand-dug wells (OHDW), springwater (SW), public bore wells (PBW), and bore wells owned by private individuals (BWP), and analyzed after filtration and sometimes dilution. The cations were analyzed using inductively coupled plasma-optical emission spectrometry (ICP-OES). The anions were analyzed by chemically suppressed ion chromatography (IC). The ranges of the levels of the investigated parameters were as follows: Na 13.68–3,656 mg L?1, K 2.66–583 mg L?1, Mg 0.63–131.10 mg L?1, Ca 16.79–189.9 mg L?1, Cl? 8.61–4,340.97 mg L?1, F? 0–1.02 mg L?1, Br? 0–10.88 mg L?1, NO3 ? 0.18–342.4 mg L?1, NO2 ? 0–1.39, SO4 2? 4.43–534.02 mg L?1, TDS 7–6,380 mg L?1, and SAR 0.63–50. Except fluoride, most of the studied parameters in the water samples had concentrations beyond the permissible limits of the World Health Organization (WHO). The elevated concentrations are a result of seepage of contaminated water from on-site septic tanks, pit latrines, landfill leachates, fertilizer applications, and domestic effluents. These results should alert domestic water stakeholders in Zanzibar to the urgent task of initiating a quick mitigation response to control these alarming water risks.  相似文献   
889.
基于碳足迹的江西省农田生态系统碳源/汇时空差异   总被引:2,自引:0,他引:2  
利用2001~2010年江西省农业投入和农作物统计数据,采用碳排放系数法计算了江西省农田生态系统碳源/汇及碳足迹,分析了江西省农田生态系统碳源/汇时空特征,并进一步分析了碳足迹变化特征及原因。结果表明:(1)2001~2010年,江西省农业投入引起的碳排放量从2001年的11910 1×106 t,增加至2010年的5872 8×106 t,增加了103倍,农业机械化对碳排放总量贡献率最大。碳排放强度呈现先增加后减少的趋势。2008年赣州市碳排放量最多,景德镇市最少;(2)2001~2010年江西省农田生态系统碳吸收量先减少,后逐年增加,到2010年又减少,整个2001~2010年间增加3209 9×106 t。各类农作物中,水稻碳吸收量最多。2009年碳吸收量最多的是宜春市,最少的是萍乡市;(3)江西省农田生态系统碳足迹从2001年的07518×106 C〖DK〗·hm-2〖DK〗·a-1,增加至2009年的1473 4×106 C〖DK〗·hm-2〖DK〗·a-1,单位面积碳足迹呈现逐年增加的趋势。2008年碳足迹最多的是赣州市,最少的是萍乡市。南昌市、景德镇市、吉安市和宜春市表现为生态盈余,其余表现为生态赤字。江西省应减少农药、化肥等的使用,控制农业机械化,特别是赣州市,从而达到减少碳排放的目的  相似文献   
890.
Currently there is a growing interest in developing novel bioproducts and biomaterials derived from renewable sources that can reduce the dependence on fossil fuel feedstock. In this study a protein concentrate from microalgae Botryococcus braunii residual biomass (MPC) from a biorefinery process was used as a biopolymer to develop ultrafine fibers by electrospinning. Experiments were designed to study the effect of different formulations of MPC, poly(ethylene oxide) and pH on morphology and diameter of fibers. The results indicated MPC fibers from acidic solutions prepared at pH 1 had smoother and smaller diameter than those fibers from alkaline solutions (pH 12). Moreover, under the conditions studied, it was conclude that pH and the concentration of MPC were the most significant factors in determining the diameter and morphology of the fibers obtained. Fourier transform infrared analysis showed there is a slight frequency shift for the secondary structure of MPC as induced by change in pH of the polymer solutions. Likely this change in the protein structure improved the physical chain entanglement in the polymer blend. The results of this work revealed a potential to develop fibers from MPC from residual biomass by a promising technique that may find many end-use applications.  相似文献   
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