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31.
Soil to plant transfer factor (TF) of60Co and 65Zn was determined fromradioisotope experiments on plants grown in pots underoutdoor ambient tropical conditions for three growingseasons (1995–1998). The TFs were obtained fordifferent plants/crops such as, rice, bean, peanutspineapple, cabbage, tomato, spinach and grass. Theaverage TF values of 60Co are found to be 0.087,0.15, 0.12, 0.67, 0.28, 0.79, 1.03 and 0.34respectively for the above mentioned plants/crops. Incase of 65Zn, the average TF values are found tobe 2.24, 1.17, 0.89, 1.09, 0.78, 1.34, 2.92 and 1.78,respectively, for the above mentioned plants/crops. Thedata will be useful to assess the radiation exposureto man associated with the releases of radionuclidesfrom nuclear facilities by means of radiologicalassessment models that require transfer factors asinput parameters to predict the contamination ofradionuclides in foodchain.  相似文献   
32.
Assessment of the food chain mobility of heavy metals inthe natural ecosystem receives more attention nowadays. Inthe present study, mulberry-silkworm food chain has beenfocused as a templet to assess the biomobility of heavymetals in soil-higher plant-insect hierarchy. Both in thecase of Cd and Cu treatments, higher mobility wasobserved in the level-1 (soil–root) followed by level-3(leaf–larva), level-4 (larvae–faecal) and level-2(root–leaf). Consequently, roots accumulated more amountsof Cd and Cu, with a limited transport to the leaves.Among the two metals (Cd and Cu) tested, in the plant,the transfer potential of Cd exceeds that of Cu. Whereasin the case of leaf–larval transfer, Cu precedes overCd. Accumulation of Cd and Cu in all the levels (1–4)tested showed a concentration dependent increase, except inthe level 4 (larva–faecal) of Cd treatment where adeclining trend was noticed.  相似文献   
33.
Modeling rhizofiltration: heavy-metal uptake by plant roots   总被引:1,自引:0,他引:1  
The discovery of phytoaccumulation potential of plant species has led to its application for remediation of heavy-metal-contaminated soil and wastewater, which is termed as phytoextraction/rhizofiltration. For prediction, analysis, planning and cost-effective design of such systems, mathematical models not only are used as a screening tool but also provide optimal parameters like harvesting time, irrigation schedule, etc. Several laboratory and field scale studies have been carried out in the past, and mathematical expressions have been developed by various researchers for different phenomena like metal adsorption in soil, plant root growth with time, moisture and metal uptake by plant root, moisture movement in unsaturated zone, soil moisture relationship, etc. The complete design of any such phytoremediation program would require the knowledge of behavior of heavy-metal movement in soil, water and plant root system. In this paper, a model for simulating heavy-metal dynamics in soil, water and plant root system is developed and discussed. The governing non-linear partial differential equation is solved numerically by implicit finite difference method using Picard's iterative technique, and the formulation has been illustrated using a characteristic example. The source code is written in MATLAB.  相似文献   
34.
介绍了国内外农村环境质量监测的发展历程和现状,总结了现行农村环境质量监测体系在体制机制、技术体系、应用支撑和数据共享等方面存在的主要问题,分析了"十四五"期间农村环境质量监测面临的挑战和机遇,指出"十四五"是农村生态环境保护的关键期、攻坚期和窗口期。根据环境管理对农业农村工作的新要求,构建了包括村庄、区域和流域3个层次及涵盖空气、地表水、饮用水、土壤、生态、污染点源和面源等监测内容的"十四五"农村环境质量监测体系,并提出了相应的保障措施,以期为我国农村生态环境保护提供更有力的技术支撑。  相似文献   
35.
Field experiments were carried out during 1996–97at Gulawathi, Muthiani and Salarpur Villages, IARI Farm, NewDelhi and NCPP Campus, Dadri to evaluate changes in soilcharacteristics and growth of wheat (Triticum aestivum L.),mustard (Brassica juncea L.), lentil (Lence esculentaMoench.), rice (Oryza sativa L.) and maize (Zea mays L.) byvarying amounts of flyash addition (up to 50t ha-1) in soils atsowing/transplanting time of crops. Flyash addition in areasadjoining NCPP Thermal Power Plant, Dadri, Ghaziabad, U.P.ranged from 5–12 t ha-1 yr-1 in 1995–96. Shoot and root growthand yield of test crops at different locations after flyashincorporation resulted in beneficial effects of flyashaddition in most cases. The silt dominant texture of flyashimproved loamy sand to sandy loam textures of the surfacesoils at the farmers' fields. The increased growth in yield ofcrops with flyash incorporation was possibly due tomodifications in soil moisture retention and transmissioncharacteristics, bulk density, physico-chemical characterssuch as pH and EC and organic carbon content. The response offlyash addition in the soil on soil health and cropproductivity needs to be evaluated on long-term sustainableaspects.  相似文献   
36.
A method is proposed to build integrated models (also called Metamodels) aimed at quantifying the economic efficiency of air quality policies. This Metamodeling approach is based on the coupling of two complementary models, that operate at different scales in space and time, and which represent the economic and the physical and chemical processes, respectively. The joint consideration of the physico-chemical and techno-economic structure of the pollution control problems permits a comprehensive evaluation of air pollution abatement strategies. The motivating pollution control problems include urban-regional air quality management through efficient energy and traffic control policies. A pilot study, exploiting data collected in the Geneva canton (Switzerland), is used to demonstrate the potential of the approach.  相似文献   
37.
报道了利用N,N─二甲基苯胺为偶联试剂的Criess反应以示波极谱法测定NO_2~-的测试方法。在拟定的实验条件下,NO_2~-在4.0×10~-3~4.8×10~-1μg/ml范围内与极谱波波高呈良好的线性关系。环境水测定的相对标准偏差小于l%,回收率在97%~101%之间。  相似文献   
38.
大气微生物与气象条件及大气污染物的灰色关联分析   总被引:4,自引:0,他引:4  
根据大气微生物浓度、气象因子和大气污染理化因子的监测结果,应用灰色关联分析原理,分析研究大气微生物浓度与气象条件和大气污染物的关联程度,说明气象因子对各类微生物浓度的影响大于大气污染因子,特别是对耐高渗透压霉菌。  相似文献   
39.
煤中有害元素对环境和人体健康影响的较为全面的评价体系一直未建立,环保部门也缺乏系统性评价参数对电厂等在煤煤过程中有害元素排向大气的释放量进行监测估算。本文在查阅大量资料(主要为外文)的基础上,认为评价煤中有害元素对环境和人体健康影响的参数应该包括以下方面的数据C、H、O、N、无机硫,有机硫,有害微量元素的含量,分布规律,赋存状态,迁移转化行为(在燃煤过程中),洁净能力,淋滤力,矿物质,有机化学特征,煤炭学特征,并对煤中有害元素的污染方法进行探讨,如果上述各参数的数据被全面提供,并据此数据作针对性的抑制措施,煤中有害元素对环境和人体健康危害影响必将降低到最小。  相似文献   
40.
华北山区温度推算模式和应用   总被引:2,自引:0,他引:2  
利用华北山区气象站观测的温度与其所在纬度、经度和高度,分山区建立宏观地面气温场方程。采用1:20万地形图,以10'经、纬度为步长,判读其高度值,代入已建立好的方程中,经地形项订正,推算华北山区年、月平均温度、年较差和ΣT'≥10℃,其精度达极显著水平。计算结果使我们对华北山区热量资源有了新的认识,最后求算华北山区的主要水果最优品质种植上限高度。  相似文献   
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