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211.
M.A. Batiha A.A.H. Kadhum A.B. Mohamad M.S. Takriff Z. Fisal W.R. Wan Daud M.M. Batiha 《Process Safety and Environmental Protection》2009,87(2):121-134
Many pesticides used in agricultural activities are considered environmentally non-volatile. The main purpose of this paper is to develop multimedia model to be used as a tool to predict the overall fate and transport of non-volatile organic chemicals (NVOCs) dynamic in the agro-ecosystem. The model was developed based on the EQuilibrium Criterion (EQC) model for type 2 chemicals introduced by Mackay and colleagues in 1996. Mackay’s model only considered four environmental compartments, which are air, water, soil and sediment. The present model adds the vegetation compartment, in addition to previous compartments that shape the agro-ecosystem. The vegetation compartment is described by two sub-compartments consisting of the above ground plant (AGP) and roots. The model was parameterized for the Cameron Highlands region, Malaysia, and runs with an illustrative emission rate of 1 kg h?1 into the air for three selected pesticides, namely, mancozeb, spinosad and chlorosulfuron. The simulation results with and without vegetation compartment were compared. The estimated results indicating that the AGP captures 99.9% of introduced NVOCs (i.e., of 100% or 1 kg h?1) and transfers them to the ground below due to the slight degradation losses of 10?4% and the non-volatility property of the evaluated chemicals. Root uptake of chlorosulfuron accounted the highest removal process from soil while degradation of spinosad in the soil is the major loss mechanism. Leaching to groundwater loss for mancozeb is about 2-fold greater than that of degradation, which together accounted the major removal process from soil. Based on the estimated results of mass distribution on the overall system, vegetation compartment accumulates 0.04%, 0.5% and 2.02% of the mancozeb, spinosad and chlorosulfuron, respectively. 相似文献
212.
Fast transformation of roxarsone into toxic arsenic species with ferrous iron and tetrapolyphosphate
Chen Na Wan Yichao Ai Zhihui Jia Falong Zhang Lizhi 《Environmental Chemistry Letters》2019,17(2):1077-1084
Environmental Chemistry Letters - Organoarsenic compounds have been widely used as feed additives in livestock and poultry breeding. They are excreted in manure and thus cause environmental... 相似文献
213.
Wan Liang Wang Chengyuan Wang Shanyong Zang Jianing Li Jun 《Environmental geochemistry and health》2022,44(9):3101-3114
Environmental Geochemistry and Health - Environmental emergencies have become a severe challenge to human society due to their great harmfulness, which seriously restrict the sustainable... 相似文献
214.
为了探讨地震作用下动土压力沿高程和滑面的响应规律,通过大型振动台实验输入X向和Z向地震波,输入幅值逐级增大直到边坡破坏,对沿滑面和沿高程的5个土压力传感器的动土压力峰值分布规律进行分析,并利用基于小波变换的能量提取工具对加载X向和Z向的EL波进行分解,分析其在不同频带的动力响应特性,并进行了加速度峰值分析与动土压力峰值的组合响应分析。研究结果表明:(1)土压力沿高程和滑面都呈现非线性增加的趋势,加载X向地震波对滑面土体应力影响较为显著,而加载Z向地震波对坡顶面附近土体应力影响较为显著,且加载Z向地震波土压力沿高程放大趋势比加载X向地震波更明显;(2)输入加速度峰值0.6g时,滑体开始向下滑动,贯通破裂面的产生和动土压力峰值以及加速度峰值同时突变可作为边坡破坏的依据;(3)使用基于小波变换的能量提取工具对各频段的能量进行提取,发现第一频段的能量占比在95%以上,说明第一频段内土体响应最为剧烈,黄土边坡对地震波运动过程中高频部分具有"滤波作用",因此进行防护设计时应把这一现象作为设计的考虑因素之一。 相似文献
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217.
北京平原区夏垫断裂的多源遥感影像特征 总被引:2,自引:0,他引:2
1679年9月2日三河—平谷8.0级地震在地表形成总体走向N40°~45°E,倾角60°~70°,长达10 km的破裂带。该文采用Landsat-8、SPOT-5、SAR、GDEM、Google Earth多源遥感影像研究夏垫断裂的遥感影像特征。利用ERDAS软件,对Landsat-8影像按7∶4∶2依次为R、G、B分量作彩色合成增强处理,突出影像的线性构造特征;对Landsat-8和SPOT-5影像、Landsat-8和SAR影像分别进行融合处理,丰富影像的光谱信息;对GDEM与SPOT影像进行三维叠加,突出影像的三维特征;对SAR影像进行斑点压缩、方向滤波处理,突出影像平行断裂方向的线性特征。文中分析、对比了Google Earth和SPOT-5影像上地震陡坎的特征,陡坎在SPOT-5影像上表现较明显,但在影像上表现不出较低陡坎,同时,在两种影像上容易将绿色植被、狭窄道路或其它地物误认为陡坎;SAR滤波后的影像表现出暗色的线性条带;Landsat-8和SAR融合后的影像表现出较宽的异常条带,该条带指示断裂带所在位置。 相似文献
218.
北京平原区夏垫活动断裂滑动速率及古地震复发间隔 总被引:3,自引:0,他引:3
搜集了有关夏垫断裂钻孔测年数据,采用最小二乘法对数据进行拟合分析,拟合结果显示夏垫断裂滑动速率在地段和时段上均存在差异,且在时段上的差异更加明显。前20 ka以来滑动速率相对较小(0.13~0.30 mm/a);前26 ka~20 ka,滑动速率较大(1.38~2.56mm/a),约为前20 ka以来滑动速率的9~11倍。利用潘各庄探槽、东柳河屯探槽、齐心庄探槽、大胡庄探槽、地震联合钻孔剖面及钻孔资料判定除1679年三河-平谷8级地震外,前20 ka以来夏垫断裂还存在6次古地震事件,古地震平均复发间隔约为3 000 a。 相似文献
219.
Seasonality is often the major exogenous effect that must be compensated for or removed to discern trends in water quality. Our objective was to provide a methodological example of trend analysis using water quality data with seasonality. Selected water quality constituents from 1979 to 2004 at three monitoring stations in southern Florida were evaluated for seasonality. The seasonal patterns of flow-weighted and log-transformed concentrations were identified by applying side-by-side boxplots and the Wilcoxon signed-rank test (p < 0.05). Seasonal and annual trends were determined by trend analysis (Seasonal Kendall or Tobit procedure) using the U.S. Geological Survey (USGS) Estimate TREND (ESTREND) program. Major water quality indicators (specific conductivity, turbidity, color, and chloride), except for turbidity at Station C24S49, exhibited significant seasonal patterns. Almost all nutrient species (NO(2)-N, NH(4)-N, total Kjeldahl N, PO(4)-P, and total P) had an identical seasonal pattern of concentrations significantly greater in the wet than in the dry season. Some water quality constituents were observed to exhibit significant annual or seasonal trends. In some cases, the overall annual trend was insignificant while opposing trends were present in different seasons. By evaluating seasonal trends separately from all data, constituents can be assessed providing a more accurate interpretation of water quality trends. 相似文献
220.
The distribution coefficient, Kd, is often used to quantify heavy metal mobility in soils. Batch sorption or column infiltration tests may be used to measure Kd. The latter are closer to natural soil conditions, but are difficult to conduct in clays. This difficulty can be overcome by using a laboratory centrifuge. An acceleration of 2600 gravities was applied to columns of London Clay, an Eocene clay sub-stratum, and Cu, Ni, and Zn mobility was measured in centrifuge infiltration tests, both as single elements and in dual competition. Single-element Kd values were also obtained from batch sorption tests, and the results from the two techniques were compared. It was found that Kd values obtained by batch tests vary considerably depending on the metal concentration, while infiltration tests provided a single Kd value for each metal. This was typically in the lower end of the range of the batch test Kd values. For both tests, the order of mobility was Ni>Zn>Cu. Metals became more mobile in competition than when in single-element systems: Ni Kd decreased 3.3 times and Zn Kd 3.4 times when they competed with Cu, while Cu decreased only 1.2 times when in competition with either Ni or Zn. Our study showed that competitive sorption between metals increases the mobility of those metals less strongly bound more than it increases the mobility of more strongly bound metals. 相似文献