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851.
Chlorobenzenes in waterweeds from the Xijiang River (Guangdong section) of the Pearl River 总被引:3,自引:0,他引:3
The Xijiang River is the major source of water for about 4.5 millions of urban population and 28.7 millions of rural population. The water quality is very important for the health of the rural population. The concentration and distribution of chlorobenzenes (CBs) in both water and waterweeds collected from 4 stations in the Xijiang River (Gangdong section) of the Pearl River in April and November were determined. The result showed that nearly every congener of CBs was detected. The total contents of CBs (∑CBs) in the river water ranged from 111.1 to 360.0 ng/L in April and from 151.9 to 481.7 ng/L in November, respectively. The pollution level of CBs in the water in April was higher than that in November. The contents of ∑ CBs in waterweeds ranged from 13.53×102 μg/g to 38.27×102μg/g dry weight (dw). There was no significant difference between April and November in waterweeds. The distribution of CBs in roots, caulis, and leaves of Vallisneria spiralis L. showed different patterns. The leaves mainly contained low-molecular-weight CBs(DCBs), whereas the roots accumulated more PCBs and HCBs. The average lgBCFlip (bioconcentration factor) of CBs ranged from 0.64 to 3.57 in the waterweeds. The spatial distribution character of CBs in the Xijiang River was: Fengkai County < Yunan County <Yun'an County < Gaoyao County according to the ∑CBs, and the pollution deteriorated from the upstream to the downstream of the Xijiang River. Further analysis demonstrated that the discharge of waste containing CBs may be the main source of CBs pollution in the Xijiang River. 相似文献
852.
853.
Laboratory longitudinal diffusion tests: 1. Dimensionless formulations and validity of simplified solutions 总被引:1,自引:1,他引:0
To obtain reliable diffusion parameters for diffusion testing, multiple experiments should not only be cross-checked but the internal consistency of each experiment should also be verified. In the through- and in-diffusion tests with solution reservoirs, test interpretation of different phases often makes use of simplified analytical solutions. This study explores the feasibility of steady, quasi-steady, equilibrium and transient-state analyses using simplified analytical solutions with respect to (i) valid conditions for each analytical solution, (ii) potential error, and (iii) experimental time. For increased generality, a series of numerical analyses are performed using unified dimensionless parameters and the results are all related to dimensionless reservoir volume (DRV) which includes only the sorptive parameter as an unknown. This means the above factors can be investigated on the basis of the sorption properties of the testing material and/or tracer. The main findings are that steady, quasi-steady and equilibrium-state analyses are applicable when the tracer is not highly sorptive. However, quasi-steady and equilibrium-state analyses become inefficient or impractical compared to steady state analysis when the tracer is non-sorbing and material porosity is significantly low. Systematic and comprehensive reformulation of analytical models enables the comparison of experimental times between different test methods. The applicability and potential error of each test interpretation can also be studied. These can be applied in designing, performing, and interpreting diffusion experiments by deducing DRV from the available information for the target material and tracer, combined with the results of this study. 相似文献
854.
分析比较了相关分析法、多元线性回归法与逐步回归法在环境影响因子辨识中的功能异同点。以甘肃省白银市为例 ,用 3种统计学方法对城郊土壤 -作物系统重金属污染影响因子进行判别 ,提出了研究区土壤污染修复方案选择指标的建议 相似文献
855.
Panichayapichet P Nitisoravut S Simachaya W 《Environmental monitoring and assessment》2007,135(1-3):181-193
The aim of this study was to investigate the spatial distribution of heavy metal in soil and evaluate the dissolution of metal
from soil to ponded-surface water, leaching through soil profiles and metal uptake in grass as related to different land-use
practices. The data provided a scientific basis for best-management practices for land use in Khli Ti watershed. The watershed
has a Pb-contamination problem from the previous operation of a Pb-ore concentrator and abandoned Zn–Pb mine. Sampling sites
were selected from a land-use map, with land-use types falling into the following four categories: forest, agricultural land,
residential area and road. Soil, ponded-surface water, grass samples and soil profiles were collected. The study related soil
characteristics from different land-use practices and locations with observed metal concentrations in ponded-surface water
and soil. High enrichment factors of Pb and As in soil were found. Partitioning coefficient, Kd values were in the order: Cr > Pb > Ni > Cu > Cd > Zn. Soil disturbance from land-use activities including tillage and traffic
increased leaching of trace metal from soils. Pb in soil was significantly taken up by grass even though the Transfer Factor,
TF values were rather low. Agricultural activities in the watershed must be limited. Moreover, land encroachments in the upper
and middle part of the watershed which have high potential of Pb must be strictly controlled in order to reduce the Pb contamination
from non-point sources. 相似文献
856.
857.
厦门市大气可吸入颗粒物源解析的研究 总被引:5,自引:2,他引:3
采用2004~2005年对厦门大气中PM10开展的3期采样分析数据,利用主因子分析法定性分析厦门大气中可吸入颗粒物的主要来源,并结合多元线性回归法,求出定量的结果。分析结果表明,影响厦门市可吸入颗粒物的主要来源有四种:工业燃煤、汽车尾气、土壤风沙尘和海盐粒子,其中二次粒子为主要污染源,贡献率为30.0%,其次为汽车尾气占29.4%,土壤风沙和建筑尘的贡献约占21.7%,海洋粒子的贡献为6.5%,不可识别源18.1%。 相似文献
858.
859.
地下水中VOC挥发因子模型的研究 总被引:2,自引:0,他引:2
建立了一个计算地下水中挥发性有机物(VOC)挥发因子的模型.选用半挥发性的1,2,4-三氯苯和挥发性的四氯乙烯为VOC的代表,分别计算了非饱和区土壤为砂土和粘土时的挥发因子.结果表明:蒸发使VOC的挥发因子增大,而下渗则使VOC的挥发因子减小;不论VOC的挥发性强弱,蒸发(下渗)对挥发因子的影响均比较明显;蒸发情况下,非饱和区土壤性质对挥发因子的影响不明显,而下渗情况下,非饱和区土壤性质对挥发因子的影响则趋于明显;此外,当非饱和区土壤为粘土时,VOC的挥发因子受蒸发(下渗)的影响更明显. 相似文献
860.
大气降水化学的统计学分析——以浙江省金华市为例 总被引:1,自引:0,他引:1
运用相关分析、因子分析和聚类分析等统计学方法,对2004-2005年间浙江省金华市的大气降水化学组成和分布特征进行了分析.结果表明,SO2-4,NH 4,Ca2 ,NO-3和H 是降水的主要离子,降水的pH值、电导率及离子组分均呈明显的正偏态分布,降水样品以低离子含量的样本为主.降水中水溶性离子主要分为4类,SO2-4,NH 4,NO-3,Ca2 和F-主要来自人为活动的贡献,K 和Mg2 主要来自土壤、沙尘等地壳来源,Na 和Cl-属于典型的海盐性成分,H 则反映了各种离子中和作用对降水酸度的综合影响. 相似文献