The effect of simulated rain on folpet and mancozeb residues on grapes and on vine leaves

Artificial rainfalls were used to determine the effect of the amount of the rainfall and the time interval between pesticide application and rainfall event, on folpet and mancozeb residues on grapes and vine leaves. Forty-five mm of rain were administered to the vineyard in different amounts (45; 30+15; 15+15+15 mm). Folpet showed good rainfastness on the grapes and on the leaves. A modest decrease was observed only in the experiments that had received 45 mm of rain at one go. Mancozeb showed a lower rainfastness, since a portion of the deposit was easily washed off also by a modest rainfall. The percentage of this portion was higher in the grapes (38%) than in the leaves (20%). The data obtained in these experiments show that, in the case of folpet, it is not necessary to repeat the treatment when it rains the day after, while it is recommendable to repeat it in the case of mancozeb.     

基于超临界技术的印刷线路板资源化方法研究

印刷线路板的回收由于其结构和组成材料的复杂性，被认为是电子电器产品回收中的重点和难点之一。提出了将超临界流体技术应用于废弃印刷线路板的回收工艺，研究出了一种环境友好的废弃印刷线路板回收方法。建立了回收模型及回收实验平台，并使用正交实验设计方法对实验进行设计，利用SPSS分析软件对实验数据进行了分析研究并结合实际实验结果得出了最佳工艺参数。通过对反应生成物进行质谱分析，推测出了生成物的主要组分，并据此对反应机理进行了研究。     

Effect of ozone on growth of mosses on disturbed forest soil

Mixed forest floor organic matter and upper mineral soil from a 1580 m elevation conifer-hardwood stand in the Pisgah National Forest, NC, was placed in 4-cm diameter x 21-cm deep tubes and exposed to 0.00, 0.08, 0.16, 0.24 or 0.32 microl O3/liter air (ppm). Twelve tubes in each of three replications/treatment were fumigated in continuously-stirred tank reactors in a greenhouse for 6 h/day on 4 consecutive days/week. Soil was watered 3 days/week with deionized water amended with ions and adjusted to pH 4.3 with H2SO4 + HNO3 (70 meq SO4(2-): 30 meq NO3(-)). After 10 weeks the amount of soil surface covered by moss (predominantly Ditrichum pusillum, but also D. lineare, and Pohlia nutans) was estimated visually and assigned a rating on a scale of: 1 = 0-25%; 2 = 26-50%; 3 = 51-75%; 4 = 76-100%. Linear regression analysis revealed a significant (p < 0.001) negative relationship between coverage ratings and O3 concentration. Surface coverage in tubes exposed to 0.32 or 0.24 ppm was about half of that for 0.00 ppm (mean ratings of 1.1, 1.4 and 2.6, respectively). Coverage differences appeared to be due in part to O3 suppression of plant numbers. Linear regression analysis also revealed a significant (p < 0.001) negative relationship between heights of D. pusillum plants (measured after 12 weeks treatment) and O3 concentration.     

Research on the impact of forest stand structure on atmospheric deposition

Dry and wet deposition onto thirty forest stands in relation to stand structure is studied by sampling throughfall and bulk precipitation. Nine measurement sites are situated in Pseudotsuga menziesii stands, ten in Pinus sylvestris and eleven in Quercus robur stands. All stands are situated within a radius of 1.2 km to assure a more or less equal air pollution load. In each stand, detailed forest structure inventories are made to determine aerodynamic roughness, collecting efficiency and surface area parameters. Measurements to data cover a four month period (April-July 1990). First results show relatively high throughfall deposition in Pseudotsuga menziesii stands. Lowest throughfall fluxes are recorded for Quercus robur and intermediate values for Pinus sylvestris stands. There are indications of a relatively strong canopy exchange in Quercus robur stands during the measurement period. Many results from forest stand structure inventories are not available yet. However, a strong relation is observed between throughfall deposition in Pseudotsuga menziesii stands and total crown volume.     

Research on financing strategy of low-carbon supply chain based on cost-sharing contract

Environmental Science and Pollution Research - The paper considers a low-carbon supply chain which consists of a capital constrained manufacturer and a retailer. We consider the retailer takes part...     

酸雨对苏州市文物古建筑的影响初探

近年来，苏州市区酸雨出现频率增加，降水pH值下降，威胁着众多的文物古建筑。因此从苏州现存文物古建筑的五种材质入手，剖析酸雨对文物古建筑的影响，并对国家重点保护文物罗汉院双塔及正殿遗址典型的案例进行了剖析。     

基于层次分析法的坦塘垃圾填埋场适宜性评价

垃圾填埋场场址的适宜性评价是生活垃圾填埋场建设和运营的前提和基础。以湖南省永州市坦塘垃圾填埋场为例,在分析研究区的地质与水文地质条件的基础上,确定了填埋场适宜性的影响因素为填埋场规模、运输条件、环境条件、建场条件和地质条件,具体包括填埋场面积及容量、综合路况条件、对地表水体污染的可能性、地形平坦程度以及场地是否处在岩溶区等条件,明确了局部地区岩溶发育是制约其适宜性的主要因素。结合垃圾填埋场的建设情况和相关规范、标准,采用层次分析法对坦塘垃圾填埋场进行适宜性评价。评价结果表明,坦塘垃圾填埋场是一个适宜场地,评价结果与实际情况相符。     

土壤固相吸附砷的研究进展

砷是一种常见的有毒元素，土壤砷污染与修复问题已引起世界范围的广泛关注。土壤原位修复是消除土壤砷污染的有效方法，其中砷在土壤固相上的吸附也是近年来的研究热点。土壤固相广泛存在于土壤中，并具有表面积大和表面电荷等理化性质，它可通过与砷酸根阴离子发生表面配位反应，形成内外层配位体等方式来固定土壤中的砷，以降低金属离子的迁移能力和有效性，是一种有效的原位减轻砷污染的方法。文中简单介绍了砷污染的现状、危害和赋存状态，重点介绍了铁铝锰的氧化物和氢氧化物、粘土矿物、有机质等土壤固相对砷的吸附机理及其影响因素，旨在更好地掌握砷的吸附行为。     

基于平均负荷的降雨径流污染负荷模型研究

在九寨沟旅游景区,对公路和栈道进行人工降雨径流污染负荷的过程研究。浓度过程曲线表明,初始高浓度与平台期浓度之间相差3~5倍,而负荷过程曲线表明,各时段负荷曲线无明显峰值存在。这意味着污染物平均浓度的获取,需要降雨径流的水量水质同步监测数据的较大样本,才能消除随机性影响。而各时段负荷数据向平均负荷期望收敛的速度,将比平均浓度期望更快。利用这一规律,以平均负荷值代替降雨事件的污染物平均浓度(EMC),构建了基于平均负荷值的年地表径流负荷模型。本模型只需要有限场水量水质同步监测数据,就可获得特定地区面源污染物的平均负荷值。在消除随机不确定性同时,提高了可操作性。采用研制的模型,计算出九寨沟各子区公路面源的TP排放负荷,在0.87~2.07 kg/a之间,栈道面源TP排放负荷,在0.27~1.22 kg/a之间。     

回流比对缺氧/好氧生活污水处理装置处理效果的影响

在缺氧／好氧工艺的不同回流比条件下，对处理效果特别是脱氮效果进行了研究。结果表明，混合液和污泥合并回流，当回流比从R=4到R=7时，均能获得良好的脱氮效果，TN去除率达到75．4％以上，出水TN〈10mg／L。而回流比的变化对BOD的去除效果影响较小。当BOD污泥负荷从0．096kg／（kg&#183;d）降低到0．063ks／（kg&#183;d）时，对TN和BOD的去除率影响都很小。     

基于生物表面活性剂的柴油微乳体系构建与性能研究

以生物表面活性剂鼠李糖脂（RL）为表面活性剂，中长碳链正构醇（正丁醇、正戊醇、正己醇、正庚醇及正辛醇）为助表面活性剂，采用滴定法制备RL／柴油／正构醇／水柴油微乳体系，并考察了表面活性剂用量（Km）、助表面活性剂醇的种类及用量（δas）及离子强度对柴油微乳体系最大增溶水量（Wo）的影响，并对不同条件下获得的柴油微乳体系的运动粘度（μ）和表面张力（γ）进行了表征。通过荧光法测得RL在柴油中的临界胶束浓度CMC为7g／L。当生物表面活性剂与柴油的质量比Km为0．02，助表面活性剂选用正庚醇且醇与表面活性剂的质量比δgs为0．1，NaOH溶液质量分数为0．06％时，柴油微乳体系的肛和T较低，形。最大，性能较佳。     

聚丙烯酰胺对活性污泥特性的影响研究

高分子混凝剂PAM投加是强化污泥造粒的有效方法,但PAM的投加对活性污泥中微生物群落以及对其生化降解性能的影响尚缺乏系统性研究。为此,通过实验室小型实验,在SBR中连续投加PAM,运用FISH等微生物检测技术,研究了PAM对活性污泥的影响。在PAM投量为3 mg/L的条件下,反应器中活性污泥的生长过程与对照反应器没有根本性差别,且PAM投加后MLSS浓度和单位重量污泥的生物量均有一定增大,污泥的沉降性能也得到改善。FISH检测的结果表明,与对照反应器相比,总细菌、亚硝化菌、硝化菌的个数分别由9.1×105、1.8×105和1.1×105CFU/mL增长到1.0×106、2.0×105和1.2×105CFU/mL,说明PAM没有对各种菌落的生长产生不利影响。连续运行80 d的结果也表明,投加PAM的反应器中COD和氨氮的去除均有所改善。     

Effects of humic substances on photodegradation of bensulfuron-methyl on dry soil surfaces

The photodegradation of the herbicide bensulfuron-methyl on dry soil surfaces in the presence and absence of humic substances was investigated under Xe lamp irradiation. A rapid rate of disappearance occurs in the humus-removed soil. The presence of humic acid (HA) and fulvic acid (FA) reduces degradation rates and has a quenching effect on the photodecomposition of bensulfuron-methyl. The quenching effect increases with increasing HA and FA concentration in soil. HA has a slightly greater ability to quenching the photolysis compared to FA. In addition, co-effects of HA and FA on quenching the photolysis are stronger than single effects of HA or FA.     

基于人工神经网络的街道峡谷NOx浓度的数值模型研究

通过对反向传播人工神经网络的算法和网络结构的研究，发现拟牛顿算法训练速度较快，能够较好地接近误差目标值，同时建立了包括输入层、隐含层、输出层的人工神经网络三层拓扑结构。通过对街道峡谷人工神经网络的训练，模拟计算了街道峡谷NOx浓度分布值。结果显示，训练误差和测试误差比为1．11，训练样本的模拟值与实测值的相关系数为0．93，测试样本的模拟值与实测值的相关系数为0．87，模拟值与实测值的相关系数均高于显著水平为α=0．05与α=0．01所对应检验性表的相关系数临界值。该模型能够用于街道峡谷污染物浓度的模拟计算，具有较好的泛化能力。     

容积负荷对厌氧氨氧化反应器运行影响的研究

采用1套有效容积为3 L的厌氧复合床作为厌氧氨氧化反应器,用提高进水基质浓度和缩短反应器水力停留时间2种方式提高反应器的容积负荷,进而研究反应器最佳的进水浓度和水力停留时间。结果表明,在HRT为24 h的条件下,反应器最佳进水浓度NH4+-N与NO2--N在110 mg/L左右;通过调节HRT发现,当HRT大于8 h时,NH4+-N与NO2--N的去除率都在80%以上。     

城市污水厂污泥替代营养盐培养海水小球藻的研究

为了城市污水厂污泥的资源化利用,对污泥替代F/2培养基培养海水小球藻(Chlorella pacifica)进行了研究。首先采用研磨-离心法制备污泥抽提液,将其与F/2培养基按体积比7∶3混合,接种微藻并在优化的条件下培养6 d,逐日测定混合液中无机氮、磷的浓度,培养结束后测定微藻生物量以及干藻中蛋白质、氨基酸和重金属含量。结果表明,将微藻在最佳条件下培养6 d后,混合液中PO34--P、NO2--N、NH4+-N和NO3--N的吸收率分别达到97.32%、96.72%、97.55%和78.13%;与F/2培养基对照组相比,混合液中微藻的生物量增加11.5%;蛋白质、必需氨基酸和非必需氨基酸的含量变化不大。另外,干藻中的重金属含量符合饲料行业标准的要求。     

Studies on the sorption behaviors of nitrobenzene on marine sediments

The sorption behaviors of nitrobenzene on marine sediments were systematically investigated in this study. The nitrobenzene sorption on both HCl-treated and untreated sediments accorded well with the linear sorption isotherm. It occurred primarily through partition function of organic carbon of sediments. In comparison, the sorption behavior of nitrobenzene on H2O2-treated sediments was nonlinear and conformed to Langmuir isotherm. Sorption of nitrobenzene on H2O2-treated sediment was mainly through surface function of sediment minerals such as clays. With the increase of ionic strength (salinity), solubility of nitrobenzene in solution would decrease. At the same time, the release of dissolvable part of organic carbon into water solution would also decrease. As a result, partition coefficient and saturate adsorption amount of nitrobenzene on marine sediments increased with increasing salinity of seawater. Contrary to the influence of salinity, partition coefficient and saturate adsorption amount of nitrobenzene decreased with increasing temperature.     

基于GIS城市机动车尾气扩散迁移研究

中国城市大气污染日趋严重，汽车尾气污染所占比重越来越大。交通、道路、管制及气候条件等是影响城市机动车尾气排放的主要因素。本文根据机动车尾气研究的实际，研究了专题MGIS数据库结构， 并以广州为例，建立了基于GIS的城市机动车尾气扩散迁移预报系统，在此基础上实现了机动车尾气污染状况的可视化。     

Column study of the influence of air humidity on the retention of hydrocarbons on soil

Inverse gas chromatography (IGC) is used for the analysis of the influence of air relative humidity on the retention of hexane, benzene, toluene and p-xylene in a sandy soil under experimental conditions similar to those typical of soil vapor extraction (SVE). The advantages of IGC over other techniques, are (a) an efficient use of lab resources, (b) a high sensitivity to low partitioning coefficients and (c) a closer reproduction of field conditions. In our procedure, experiments with only two samples of different mass are necessary to establish if linear isotherms can be used to describe the retention of the contaminants. This approach gives information necessary for analyzing the feasibility and design of remediation technologies with a laboratory effort significantly smaller than the adsorption/desorption cycle for isotherm determination. The retention coefficients of the contaminants decrease as humidity increases in a similar fashion for all of them, probably because the reduction in the number of the adsorption sites available for the organic compounds due to the presence of water is quite similar for all the contaminants studied. These retention coefficients may be related to those obtained for dry air conditions for all the contaminants through (R - 1)RH% = A(R - 1)dry air(B), where the parameter B is found to remain approximately constant (0.90), while the parameter A decreases linearly with the relative moisture.     

Influence of solute dissociation constants on the optimum adsorption of weak electrolytes on activated carbons

The pH of solutions has dramatic effects on the adsorption capacity of activated carbons from solutions, while the adsorption curves for weak electrolytes acquired as a function of pH show maxima at some intermediate pH. This intermediate pH is usually near the pKa of the electrolyte. Some apparent controversy inherent in these statements has, however, motivated experimental and analytical investigation of these systems. The present investigation therefore employed standard ASTM techniques in the study of adsorption systems, as well as non-linear least squares regression techniques to predict adsorption on activated carbon. It was observed that the adsorption isotherms do not indicate the existence of clear adsorption maxima for pKa values above 10. The existence of both a maximum as well as a minimum on the adsorption of a range of moderately weak electrolytes is indicated. Good agreement was observed between experimental and predicted adsorption isotherms.