湖泊水质富营养化评价的多准则神经网络法

提出了基于误差平方和准则与模糊熵准则下的多准则神经网络湖泊水质营养化评价模型，并将其应用于我国五大湖泊水质营养化的评价。结果表明，多准则神经网络用于湖泊水质营养化评价，具有简便，实用，客观和广泛的通用性     

入侵植物加拿大一枝黄花综合管理技术的研究进展

加拿大一枝黄花的入侵已经成为不容忽视的问题,产生了无法估量的经济、社会、生态损失。由于加拿大一枝黄花繁殖能力强、传播迅速、生境多样,因此该种的控制难度也大。文章综述了有关加拿大一枝黄花物理防治、化除、生物防治、植物替代等方法及其应用效果,以期为更有效地实施拿大一枝黄花的综合管理提供理论基础和实践依据。     

Immobilization and transformation of co-existing arsenic and antimony in highly contaminated sediment by nano zero-valent iron

Arsenic(As) and antimony(Sb) are usually coexistent in mine wastes and pose a great threat to human health. The As immobilization by nano zero-valent iron(n ZVI) is promising, however, the stabilization for co-occurring As and Sb is not known. Herein, the immobilization and transformation of As and Sb in n ZVI-treated sediments were evaluated using complementary leaching experiments and characterization techniques. Raw sediment samples from a gold-antimony deposit revealed the co-existence of ul...     

Ambient volatile organic compounds at a receptor site in the Pearl River Delta region: Variations, source apportionment and effects on ozone formation

We present the continuously measurements of volatile organic compounds（VOCs） at a receptor site（Wan Qing Sha, WQS） in the Pearl River Delta（PRD） region from September to November of 2017. The average mixing ratios of total VOCs（TVOCs） was 36.3 ± 27.9 ppbv with the dominant contribution from alkanes（55.5%）, followed by aromatics（33.3%）. The diurnal variation of TVOCs showed a strong photochemical consumption during daytime,resulting in the formation of ozone（O₃）. Five VOC sources were ...     

三唑酮对大型溞21天慢性毒性效应

三唑类杀菌剂是一种在农业上广泛应用的广谱性杀菌剂。三唑类杀菌剂在农田施用后能够向土壤深处迁移和扩散,从而污染土壤和地下水体,因此三唑类杀菌剂对土壤生态环境能够造成一定的破坏。选择三唑酮为研究对象,参照经济合作与发展组织(Organization for Economic Co-operation and Developement,OECD)标准方法研究三唑酮对大型溞的慢性毒性效应。21d慢性毒性研究结果表明,大型溞繁殖指标-内禀增长率是对三唑酮最为敏感的毒性参数。其慢性毒性下限值(LCL)和慢性毒性上限值(UCL)分别为40和80μg·L-1。三唑酮对于第2代大型溞,染毒的影响比对第1代的影响更大。对第2代恢复的大型溞除了第1次产卵数没有显著性差异,其他指标都有所变化,这说明毒物被转移到子代中。     

Mn对超富集植物青葙Cd毒害的缓解效应

为了探究Cd胁迫下青葙中Mn的生理作用,通过水培实验,研究在Cd暴露下(0、5和25 μmol·L-1 )施加Mn(5、100和1 000 μmol·L-1 )对青葙的干重、叶绿素含量、Cd含量和青葙根部不同区域实时Cd2+流速的影响.结果表明,提高Mn的供应水平可缓解Cd对青葙生长的抑制效应.在Cd浓度为5 μmol...     

中国粮食产量不同风险类型的地理分布

论文以中国各省份、各地区历年粮食单产为基本资料,采用统计方法,以风险分析技术为核心,定义粮食产量风险评价指标。在此基础上采用迭代自组织动态聚类分析方法分别对全国地区级和省级粮食生产单元进行了减产风险要素分区和综合风险指数分区,分区的结果反映了粮食生产风险水平的区域分异与各地区孕灾环境、致灾因子性质和生产力水平有密切联系。     

沂北水稻主产区田间土—水磷素流失潜能

选取嘉善、余姚、德清、余杭4个具有代表性浙北水稻主产区，研究了水田土－水磷素流失潜能及环境意义。4稻区高水平磷肥投入促进了土壤高磷化，土壤Olsen-P积累的同时,相应地提高了土壤生物性有效磷、水浸提磷，并提高了土壤磷素的流失潜能。稻区土壤在富磷化过程中，存在着土壤磷素的农学意义向环境意义方向演变的趋势。在非植稻期，稻区农田水体，包括沟渠水、田表水、排渠水、暗管排水等总磷（TP）平均超过了易诱发水体富营养化临界值，其中溶解磷（DRP）占总磷40％；主要是源于绿肥田表水及部分排渠中的溶解磷对稻区外水体构成了直接危害。在非植稻期，因稻区间农耕措施的差异导致了土壤富磷水平与对应田表水磷素水平不具相关性；在植稻期，施磷措施促进水田土壤富磷，相应地提高了田表水磷素水平。     

上海市第二水源长江取水口环境生物调查和质量评价——(Ⅰ.浮游生物)

本文应用水生物、污水生物体系的划分阶段,以评价上海市第二水源长江两个取水口的环境质量.1989年枯水期(2～3月)和丰水期(7月)在长江口河流段南岸的浏河和浪港二个站位,分别在近岸(5m水深)和远岸(10m水深上、下层)的断面,进行浮游植物,浮游动物调查.结果认为两个取水口应是β中污型(βm),属尚清洁带.相比之下,浏河站比浪港站差,近岸比远岸差,丰水期低潮时比高潮时差,浏河站丰水期比枯水期差,浪港站枯水期比丰水期差.其主要受自邻近河道排放水,上海市污水排放和涨落潮污水流向变化的影响,反映了河口区环境的复杂性.     

Influence of environmental temperature and relative humidity on photocatalytic oxidation of toluene on activated carbon fibers coated TiO2

TiO₂ supported on active carbon fiber (TiO₂/ACF), an absorbable photocatalyst, is a new kind of material applied in air purification. In this paper, the influence of environmental temperature (T) and relative humidity (RH) on the gas-solid adsorption of toluene and the photocatalytic oxidation (PCO) efficiency of adsorbed toluene on TiO₂/ACF were studied, and then, the purification capability of TiO₂/ACF was estimated. PCO results showed that although the PCO efficiency increased under high RH and T levels, the amount of adsorption of toluene decreased. Moreover, quantitative analysis results of intermediates indicated that more environmental risk emerged when PCO of toluene was carried out at higher environmental T and RH levels because more toxic intermediates would be accumulated on the TiO₂/ACF. So, it is significant to control the environmental T and RH conditions in the application of the PCO technique. T = 25°C and RH530% is the optimal condition for purifying toluene in our experimental system. __________ Translated from Urban Environment & Urban Ecology, 2007, 20(5): 10–13 [译自: 城市环境与城市生态]