微生物降解拟除虫菊酯类农药残留的研究进展

随着拟除虫菊酯类农药使用量不断增加,产生的农药残留问题对生态环境和人类健康造成了危害.对降解拟除虫菊酯类农药的微生物种类、降解酶和降解机制及降解酶基因克隆和构建工程菌等方面进行综述,旨在为研究和开发微生物降解拟除虫菊酯类农药残留提供参考.     

北京城市水系水环境模拟及情景分析

城市水系是流域水环境管理中最为脆弱的控制点.针对城市水系水动力条件差、有机污染和富营养化严重的问题,应用QUAL2K模型模拟、预测城市水系水环境的时空变化,并在此基础上探讨北环水系水环境管理和污染防治的合理有效方案.结果显示,经过多次调整后的模型模拟的匹配度达到了0.9135,水温、溶解氧、COD、TN、TP和Chl-...     

水库网箱养鱼环境经济学分析

以密云水库为研究对象，分析了水库网箱养鱼对水库局部水域水质和水库出水水质的影响程度，并从环境经济学角度对水库网箱养鱼进行了费用－效益分析，指出应禁止在密云水库进行网箱养鱼作业。     

一种城市生态系统健康评价方法及其应用

利用集对分析方法,将评价城市生态系统健康状况的多个指标系统合成一个与最优评价集的相对贴近度,用来描述城市生态系统健康状况.运用集对分析方法,以北京、大连、上海、武汉、厦门、广州等城市为例,对1995～2003年间的城市生态系统健康进行了评价.结果表明,不同时期各城市生态系统健康状况排序有所变化,但厦门和广州一直名列前茅.此外,对北京1992～2003年间城市生态系统健康状况的变化情况进行了具体分析,结果显示,北京城市生态系统健康状况随着时间的推移而不断改善.     

保定城区地表灰尘污染物分布特征及健康风险评价

以河北省保定市城区为研究区域,采集了保定城区内办公区、商业区、居住区、工业区、交通区和屋顶6个类别共14个采样点的地表灰尘,分析了地表灰尘重金属和营养元素N、P在不同区域的分布特征,并分析了其可能来源.最后,应用重金属健康风险评价模型（Chronic Daily Intake,CDI）对地表灰尘中Cd、Cr、Cu、Pb和Zn 5种重金属进行了健康风险评价.结果表明,城市屋顶灰尘污染物质含量普遍高于其它区域,之后依次是商业区>交通区>工业区>办公区>居住区,Cd(5.10 mg·kg-1)、Cr(470 mg·kg-1)、Pb(997 mg·kg-1)、Zn(1377 mg·kg-1)和P(999 mg·kg-1)的最大值均来自屋顶灰尘,而Cu(867 mg·kg-1)和N(19.40 mg·kg-1) 的最大值则来自商业区的地表灰尘.重金属Cd和Cr具有复合污染特征,来源复杂且多样化;重金属Pb、Zn和Cu的含量在各区域中的变化趋势较一致且显著相关,主要来源于交通排放.Cd的平均致癌风险指数均达到了1.25×10-5,超过了美国EPA 10-6的标准,由此将导致每百万人增加12.5个癌症患者,已对当地居民的身体健康造成了严重的威胁;各种重金属的平均叠加风险度达0.124,重金属摄入为慢性参考剂量的10%左右,不会对居民的身体健康产生较大的非致癌风险.     

Impact factors of the degradation of bisphenol A by nitrocellulose membrane under illumination

Nitrocellulose membrane (NCM) can produce hydroxyl radicals under illumination, which promotes the oxidative degradation of organic pollutants. In this paper, NCM was used to oxidize bisphenol A (BPA) under simulated sunlight. The effects of pH, temperature, light intensity, anion and cation on the degradation of BPA were analyzed. The photodegradation process of BPA was discussed. The optimal photolysis rate was 0.031 min^?1 when the temperature was 30°C, the light intensity was 2.67 × 10⁴ Lux, and the pH value was 9.0. The alkaline environment, temperature and light intensity can promote the photodegradation of BPA. Except for nitrate ions, anions and cations can inhibit the photodegradation of BPA. Compared with cations, anions have a greater inhibitory effect on BPA degradation. The degradation products of BPA by NCM were analyzed by gas chromatographic/mass. This study may provide useful information for the BPA degradation by NCM in complex water samples.     

Assessment on the distribution and partitioning characteristics of polycyclic aromatic hydrocarbons (PAHs) in Lake Baiyangdian, a shallow freshwater lake in China

The characteristics of polycyclic aromatic hydrocarbons (PAHs) in water, suspended particulate matter (SPM), sediments, and hydrophytes from Lake Baiyangdian, a shallow freshwater lake in China were studied. The low-molecular-weight PAHs (2-3 ring PAHs) predominated (61.2 to 84.5%) in all samples. Principal component analysis (PCA) of individual PAHs and the ratios of selected PAHs showed that the PAHs in the lake were mainly petrogenic inputs. The solid-liquid distribution coefficient (K(d)) in the water phase was much higher than the bioconcentration factor (BCF), and the leaf concentration factor (LCF) was higher than the root concentration factor (RCF) and stem concentration factor (SCF) in plant-sediment phase. Good linear log/log relationships were observed between the equilibrium partitioning coefficient (K(oc)) and the octanol-water partitioning coefficient (K(ow)), between RCF and K(ow), and between LCF and the octanol-air partitioning coefficient (K(oa)). These results indicated that PAHs accumulated more easily in SPM than in submerged aquatic plants, and some low-molecular-weight PAHs could accumulate and be translocated in the lake's media. Media characteristics, contamination sources, and physicochemical properties all affect the partitioning of PAHs among water, SPM, sediments, and hydrophytes.     

基于生态系统健康的生态承载力评价

针对自然生态系统和传统生态承载力研究中评价标准相对单一、评价结果简化、不利于实际应用等问题，提出了基于生态系统健康的生态承载力概念，探讨了其内涵和基本特征；建立了水电梯级开发对生态承载力影响和基于生态系统健康的生态承载力计量模型；给出了基于生态系统健康的生态承载力评价指标体系和标准的确定方法，初步构建了基于生态系统健康的生态承载力理论框架．以黄河流域青海片为研究区域，建立了适合该区域的基于生态系统健康的生态承载力评价指标体系、权重和评价标准，并对青海片内水电梯级建设对生态承载力的影响进行了深入分析．结果表明，黄河流域青海片水电梯级开发规划实施的不同阶段对共和县生态承载力指数均为正面影响．但对青海片和沿黄其它县均为负面影响；梯级开发规划全面实施后，将使青海片的生态承载力指数下降9．9％，生态系统健康等级也将由亚健康状态降至不健康状态。     

鲢鳙放养水平对淀山湖浮游植物群落影响的围隔实验

在淀山湖进行放养不同密度鲢、鳙的围隔实验（密度水平梯度设置为0、40、80和120 g/m3）,探索鲢、鳙的现场控藻效果。结果表明,实验后期（8—9月）,鲢、鳙放养密度为80 g/m3和120 g/m3的围隔对叶绿素a的去除效果显著（P〈0.05）;且放养密度为80 g/m3的围隔蓝藻比例降幅最明显。鲢、鳙对较大个体藻...