基于APCS-MLR模型的沱河流域污染来源解析

水污染来源的精准识别一直是水环境管理的热点和难点问题,为了解沱河流域水质特征与污染来源,该研究基于16个监测点位月尺度水质数据,采用绝对主成分-多元线性回归（APCS-MLR）模型,解析污染来源及其主要贡献.结果表明:①COD是年度超标因子,总磷和氟化物在部分月份超标,水质从汛期至11月较差.②城镇生活与城市径流是影响沱河水质的主要驱动因子,其方差贡献率达24.7%,其次为环境背景值、农村生活源、畜禽养殖业+河道内源和种植业源,其方差贡献率分别为19.6%、9.9%、8.8%和7.6%.③从最主要的超标因子COD来看,城镇生活与城市径流是主要污染源,贡献率达60%;从总氮、总磷和氨氮指标来看,种植业、农村生活和畜禽养殖业为主要污染源,总计贡献率分别为56%、54%和57%.研究显示,加快污水管网的建设完善,控制城镇污染物的排放、收集和处理是沱河水质达标的当务之急,应重点加强对农田径流和畜禽养殖污染的有效管控.      

Effects of heavy metals and nitroaromatic compounds on horseradish glutathione S-transferase and peroxidase

Glutathione S-transferase (GST) and peroxidase (POX) activities have a direct relation to the effect of stress on plant metabolism. Changes in the activities of the enzymes were therefore studied. Horseradish hairy roots were treated by selected bivalent ions of heavy metals (HMs) and nitroaromatic compounds (NACs). We have shown differences in GST activity when assayed with substrates 1-chloro-2,4-dinitrobenzene (CDNB) and 1,2-dichloro-4-nitrobenzene (DCNB). The conjugation of DCNB catalysed by GST was inhibited in all roots treated with HMs as compared to non-treated roots, whereas NACs caused induction of the activity in dependence on the exposition time and concentration of compounds. The conjugation of CDNB by GST was not affected to the same extent. The increase of GST activity was determined in cultures treated by nickel (0.1 mM) and diaminonitrotoluenes (DANTs, 0.1 mM) for 6 h, whereas the roots treated by 2,4,6-trinitrotoluene (TNT), 4-amino-2,6-dinitrotoluene (ADNT) and dinitrotoluene (DNT, 1.0 mM) needed 27 h treatment to induce the activity. The POX activity of cultures treated by HMs was inhibited to 17-35% in comparison to non-treated cultures. The POX activity of roots treated by TNT (0.1 and 1.0 mM) for 6 and 27 h and by ADNT (0.1 and 1.0 mM) for 6 h was inhibited. A partial increase of POX activity was measured in roots treated by all NACs for 27 h. The content of oxidized glutathione (GSSG) and reduced glutathione (GSH) in the roots differed significantly. It was followed as a symptom of the stress reaction of the plant metabolism to the effect of NACs and HMs.     

博斯腾湖矿化度遥感反演及空间分布特征研究

以我国最大的内陆淡水湖——博斯腾湖为研究对象,利用Terra/MODIS L1B空间分辨率为250 m和500 m的遥感反射率数据及湖水矿化度实测数据建立线性回归模型,分析湖表面矿化度的空间分布特征。结果表明:空间分辨率为500 m的1~7个波段组合建立的多元线性回归模型相关性最高(R~2=0.70),模型验证结果显示,实测值和反演值的相关系数(R~2)为0.82,均方根误差(RMSE)为0.12。利用最优模型对博斯腾湖湖面矿化度进行反演,其分布存在明显的空间梯度,西北、东北和东南湖区矿化度较高,而西南湖区和湖区南部矿化度较低。     

基于激光测风雷达的西安重污染天气过程特征指标

选取西安两次重污染天气,结合第十四届全国运动会、第十一届残运会暨第八届特奥会气象保障新建激光测风雷达数据产品研发应用,总结形成对西安重污染天气预警服务有良好参考意义的特征指标。结果表明:重污染天气发生前48 h,500 hPa上新疆至陕西一带盛行一致偏西气流,700 hPa上陕西中南部受槽前西南气流影响,-20℃等温线在40°N以北,850 hPa上-8℃等温线在关中35°N以北,西安站3 km以下存在多层逆温,温度垂直递减率小于3 ℃/km。重污染天气转为优良天气时,500 hPa上贝加尔湖一带低槽东移南压,40°N、110°E附近明显冷平流或温度锋区迅速南移影响河套至陕北,700 hPa上35°~40°N、110°E附近南移锋区经向温度梯度增至10 ℃/500 km,-20℃等温线南压至陕北北部,850 hPa上-8℃等温线移至关中南部,锋区向南移动影响陕西大部,延安、西安一带偏西南风转为偏北风,西安站3 km以下多层逆温减弱、消失,温度递减率增至5 ℃/km以上,低层过程降温超过8℃。研发的激光测风雷达产品提供了时空高分辨的近地层风场监测信息:重污染发生发展时,2 km以下各层风速小于6 m/s、维持弱下沉运动;重污染天气消散、转为优良天气时,2 km以下部分层次风速由8 m/s增至10 m/s以上,上升运动趋势与分钟尺度内波动振荡明显加强。     

静电除尘电源的发展

静电除尘电源是静电除尘系统中的关键部分,其性能直接影响除尘器的除尘效果,以静电除尘电源在节能和提高除尘效率上的关键因素为基础,对静电除尘电源的发展进行分析研究。具体阐述了静电除尘电源经历了由单相供电向三相供电、工频调压向高频逆变以及单一供电模式向混合供电模式3条较为明显的发展脉络,指出高频静电除尘电源具有控制方式灵活、输出高电压波形可控、闪络后关闭速度快和重启迅速等优点,是当今静电除尘电源的主要研究发展方向。     

一种有毒植物肆虐欧洲

近年来,德国南部和捷克乡间,有一种比成人还高的植物蔓延到田野和牧场。这种植物是19世纪作为一种观赏植物从高加索引进的。由于这种植物有丰富的花粉,深得养蜂者的青睐。但它的花和叶子中的有毒汁     

Assessing the critical level of SO2 for Scots pine in situ

A field survey was performed in eastern Finland, where measured ambient SO2 concentrations were 1.4-3.8 microg m(-3) a(-1) and bulk S deposition 0.17-0.32 g m(-2) a(-1) in 1991-1993. The accumulation of sulphur (S) in needles of Scots pine (Pinus sylvestris L.) was studied with XRF, IC and FESEM analyses and the needle damage examined under a light microscope and by SEM. Foliar N concentrations were also measured. Foliar total S concentrations were observed to be above the normal S level (500-700 microg g(-1)) over almost the whole area. Slight chlorosis and/or necrosis of the needle tips and stomatal areas, changes in the needle surface waxes and localization of S into needle tips and mesophyll cells around the stomata suggested the impact of S deposition, as did the calculations of St/Nt, and 'predicted' and 'excess' S. A concentration of about 900 microg g(-1) may be considered a critical level for foliar St in areas with low N supply.     

《中国环境科学》入网ChinaInfo(中国信息)网络资源系统《电子期刊》

为了实现科技期刊编辑、出版发行工作的电子化,推进科技信息交流的网络化进程,《中国环境科学》自1998年第1期入网“ChinaInfo(中国信息)网络资源系统《电子期刊》”.凡在本刊发表的论文将由编辑部统一纳入ChinaInfo信息服务系统,进入因特网提供信息服务.凡不同意将自己的论文纳入因特网传送交流的作者,请在来稿上注明.本刊所付稿酬包含刊物内容上网服务报酬,不再另付.ChinaInfo系统是由国家科技部立项,中国科技信息研究所组织实施,万方数据网络中心编辑制作的开放式因特网络信息资源系统,《电子期刊》作为国家“九五”科技攻关项目,是Ch…     

泛洋公司处理废轮胎有方

北京地区第一条利用废旧轮胎生产精细胶粉的生产线正在安装 ,预计今年 1 2月可投入运转。这条生产线由北京泛洋伟业科技有限公司投资兴建 ,生产线的年处理废弃轮胎量可达 1 .5万吨 ,用废旧轮胎生产出的胶粉将用来开发新型建筑材料。据了解 ,北京市现有机动车就达 1 40万辆。而机动车辆的增加也带来了废弃轮胎的大量增加。这些废弃轮胎中 ,除了少数被再利用外 ,绝大多数被随处丢弃 ,而这些废弃的橡胶制品 ,无论焚烧还是掩埋都会带来新的环境污染。我国天然橡胶资源并不丰富 ,废轮胎利用也是一个资源再利用的问题。投资兴建这条生产线的北京泛…