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991.
县、乡村防灾减灾系统工程 总被引:1,自引:1,他引:1
根据县、乡村的组织管理体系和所存在的防灾减灾问题 ,提出了建立县、乡村防灾减灾体系的构想。建议的县政府内设立“县防灾减灾 (中心 )协调办公室” ,组织实施县、乡村防灾减灾系统工程。从抓防灾减灾科普教育宣传入手 ,对全县、乡村灾害进行详细调查评估、监测预报 ,在此基础上有计划地选择小流域和重要灾害点进行治理 ,逐步达到全面推进防灾减灾工作的目的。 相似文献
992.
因污水量增加,汾酒厂污水处理站于 2 0 0 1年扩建。建成后污水站处理能力达 80 0 0m3 d。扩建部分不仅工艺流程与原系统相同,而且充分挖掘原有构、建筑物的潜力。该处理工艺技术成熟,运行稳定,出水水质优于设计要求 相似文献
993.
994.
995.
The Status of Pesticide Residues in the Drinking Water Sources in Meiliangwan Bay, Taihu Lake of China 总被引:10,自引:0,他引:10
The study was carried out to assess the levels of pesticide residues in the water of Meiliangwan Bay, Taihu Lake of China. The most commonly employed organochlorine pesticides (OCPs), organophosphorus pesticides (OPPs) and herbicide atrazine were analyzed. The water samples were collected seasonally from Meiliangwan Bay within a period of one year. The pesticides were analyzed by gas chromatography (GC) with μECD or NPD after solid-phase extraction (SPE), which was confirmed by GC with an ion trap mass spectrometry (MS). The mean concentrations were 1.98 ng/l for lindane, 0.378 ng/l for heptachlor epoxide, 0.367 ng/l for p,p′-DDE, 0.496 ng/l for p,p′-DDD, 1.06 ng/l for p,p′-DDT and 51.6 ng/l for dichlorvos, 39.0 ng/l for demeton, 346 ng/l for dimethoate, 4.12 ng/l for methyl parathion, 11.6 ng/l for malathion, 2.17 ng/l for parathion and 217 ng/l for atrazine. Generally, low concentrations of OCP were found, whereas the concentrations of the OPPs and atrazine in the water of Taihu Lake were relatively high. Heptachlor epoxide and lindane were the two most commonly encountered OCPs while dichlorvos, demeton and dimethoate were found to have much higher concentrations and occurrences than other OPPs. 相似文献
996.
997.
改性蒙脱石-壳聚糖絮凝剂处理造纸废水 总被引:2,自引:0,他引:2
将改性蒙脱石(MM)和壳聚糖(CTS)制成MM-CTS新型复合絮凝剂,对造纸废水进行絮凝处理.实验结果表明,当MM-CTS的加入量为0.10 mg/L、m(MM):m(CTS):40:1、pH=8.0、搅拌速率为140 r/min、沉降时间为15 min时,絮凝效果最佳,对造纸废水的COD去除率达66.35%,较传统絮凝剂的COD去除率提高了13.7%,药剂成本下降11.1%,具有明显的经济与环境效益. 相似文献
998.
Xun Chen Yumei Zhang Lingyan Cheng Huaping Wang 《Journal of Polymers and the Environment》2009,17(4):273-279
Rheological behavior of the concentrated cellulose/1-butyl-3-methylimidazolium chloride ([BMIM]Cl) solutions was investigated.
As polymeric fluid, solutions of cellulose in [BMIM]Cl display a marked elastic behavior under shear flow. The dependence
of the shear viscosity η, and of the dynamic modulus, on concentration, average degree of polymerization (DP) and temperature
is discussed. At lower concentrations and degrees of polymerization (DP), cellulose solutions show viscous, inelastic behavior
at low frequencies and low shear rate. At higher concentration and DP, cellulose solutions are more elastic at higher frequencies
and shear rate. Such solutions also have some usual rheological properties. The dynamic rheological responses revealed that
the Cox–Merz rule did not hold for these cellulose solutions at high deformation rate. Plotting storage modulus G′ against
loss modulus G″ gave almost a master curve which is independent of temperature and concentration, with the slope of about
1.651 for 10 wt% cellulose solutions. This value indicates the existence of microheterogeneity in the solution system. 相似文献
999.
Adsorption of lambda-cyhalothrin and cypermethrin on two typical Chinese soils as affected by copper
Jun Liu Xiaomeng Lü Jimin Xie Yafei Chu Cheng Sun Qian Wang 《Environmental science and pollution research international》2009,16(4):414-422
Background, aim, and scope Pesticides and heavy metals pollution in soil environment has become a serious problem in many countries including China.
Repeated applications of bordeaux mixture (a blend of copper sulfate and calcium hydroxide) and pyrethroid (Pys) insecticides
have led to elevated copper (Cu) and Pys concentrations in vineyard surface soils. However, few studies focused on the interaction
of Pys and heavy metals in the soil environment. Our previous studies had indicated the combined effect of cypermethrin (CPM)
and Cu on soil catalase activity. Also, we had suggested that the addition of Cu could catalyze photo-degradation of CPM and
lambda-cyhalothrin (λ-CHT) in aqueous solution and restrain their degradation in soil. To better understand the potential
influence of Cu on the fate of Pys in the soil environment, the aim of the present work was to examine the effect of Cu on
the adsorption of λ-CHT and CPM on two typical Chinese soils with different soil characteristics, which was one of the key
processes controlling the fate of Pys, and to provide more information about the potential ecological risk of chemicals on
the soil ecosystem. Fourier transform infrared and point charges analysis using the MOPAC program of the Gaussian system were
also used to reveal the probable adsorption mechanism of λ-CHT and CPM on soils.
Materials and methods Two vineyard soils with different properties were chosen as experimental samples. They were sampled from 0 to 10 cm, dried,
and sieved to 2 mm. Each soil was spiked with copper sulfate solution to obtain the following total soil Cu concentrations:
100, 200, 400, 800, and 1,600 mg·kg−1. The treated soils were incubated for 2 weeks and then dried at 20°C. For each soil sample and at each soil Cu concentration,
the adsorption of λ-CHT and CPM was measured using a batch equilibrium method. The concentration of λ-CHT was determined by
HPLC, and the amount of λ-CHT and CPM adsorbed by the soil sample at equilibrium was determined by the difference between
the initial and equilibrium concentrations in solution corrected by the blank adsorption measurement.
Results Without the addition of Cu, the adsorption of λ-CHT and CPM on Black soil is greater than that on Red soil, while the adsorption
of λ-CHT on both soils is significantly stronger than that of CPM. As the soil Cu concentration increased from 19 (or 18;
background) to 1,600 mg·kg−1, the adsorption coefficient (K
d) of λ-CHT decreased from 12.2 to 5.9 L·kg−1 for Red soil, and from 26.1 to 16.8 L·kg−1 for Black soil, whereas the CPM adsorption coefficient in both soils decreased nearly by 100% (K
d decreased from 9.4 to 0.2 L·kg−1 for Red soil and from 16.2 to 0.5 L·kg−1 for Black soil).
Discussion Pys adsorption is a surface phenomenon which depends on the surface area and the organic matter content. Thus, the Black soil,
having higher organic matter and greater surface area than that of the Red soil, show greater adsorption affinity to λ-CHT
and CPM. In our study, the different adsorption affinity of the two Pys was obtained, which was probably attributed to differences
with respect to their physical–chemical properties. Further comparison upon the two Pys was conducted. The point charges of
halogen atoms in the λ-CHT and CPM were calculated, the differences of which probably lead to the fact that λ-CHT has a stronger
binding capacity to soils than CPM. Also, FTIR spectra show that competitive adsorption occurs between CPM and Cu for the
same adsorption sites, which is responsible for the obtained suppression of CPM adsorption affected by Cu.
Conclusions Lambda-cyhalothrin shows a significantly stronger adsorption than cypermethrin on both soils. This phenomenon may be due to
several reasons: (1) λ-CHT has lower solubility and a higher octanol–water partition coefficient value than CPM; (2) λ-CHT
consists of specific isomers, whereas CPM is mixtures of eight different isomers; (3) the chlorine and fluorine atoms in the
λ-CHT have a negative point charge, whereas the chlorine atoms in the CPM have a positive point charge. As the soil Cu concentrations
increased from 19 (or 18) mg·kg−1 to 1,600 mg·kg−1, the adsorption coefficient of λ-CHT and CPM decreased on both soils. This is mainly due to a competition between Cu and
Pys for occupying the adsorption sites on soils. The information from this study have important implications for vineyard
and orchard soils, which often contain elevated levels of Cu and Pys. These results are also useful in assessing the environmental
fate and health effect of λ-CHT and CPM.
Recommendations and perspectives It is important for environmental scientists and engineers to get a better understanding of soil–metal–organic contaminant
interactions. However, pesticide adsorption involves complex processes, and shortcomings in understanding them still restrict
the ability to predict the fate and behavior of pesticide. Therefore, considerable research should be carried out to understand
the mechanism of interaction between Pys and heavy metal on soils clearly. 相似文献
1000.
K.M. Thiessen K.G. Andersson B. Batandjieva J.-J. Cheng W.T. Hwang J.C. Kaiser S. Kamboj M. Steiner J. Tomás D. Trifunovic C. Yu 《Journal of environmental radioactivity》2009
The Urban Remediation Working Group of the International Atomic Energy Agency's EMRAS (Environmental Modelling for Radiation Safety) program was organized to address issues of remediation assessment modelling for urban areas contaminated with dispersed radionuclides. The present paper describes the second of two modelling exercises. This exercise was based on a hypothetical dispersal of radioactivity in an urban area from a radiological dispersal device, with reference surface contamination at selected sites used as the primary input information. Modelling endpoints for the exercise included radionuclide concentrations and external dose rates at specified locations, contributions to the dose rates from individual surfaces, and annual and cumulative external doses to specified reference individuals. Model predictions were performed for a “no action” situation (with no remedial measures) and for selected countermeasures. The exercise provided an opportunity for comparison of three modelling approaches, as well as a comparison of the predicted effectiveness of various countermeasures in terms of their short-term and long-term effects on predicted doses to humans. 相似文献