我国实施GHS概况与企业应对GHS的措施

全球化学品统一分类和标签制度（GHS）已经在全球展开,我国也进入了实施GHS的行列,各有关部门在法规、部门规章、标准等制修订方面做了大量工作。但如何应对GHS,却是企业非常困惑的问题。通过对国家各有关部门实施GHS情况的介绍和今后国家实施GHS的思路分析。提出了企业应对GHS的措施。     

基于GIS的土地利用类型分形维数及稳定性研究——以滇池流域为例

应用GIS技术及分形理论,以云南省滇池流域为研究区,将土地利用类型划分为5类：耕地、林地、草地、水域及城乡工矿居民用地,并进行各土地利用类型图斑分形维数分析。结果表明：土地利用类型的分布具有分形结构,各土地利用类型分维值介于1.09～1.35之间,总分维值1.146。根据分维值对各土地利用类型稳定性排序：林地〉草地〉耕地〉水域〉城乡工矿居民用地。若不考虑水域影响,稳定性指数均介于0.2～0.5之间的土地利用类型面积占研究区土地总面积的80.18%,总体稳定性良好。说明在人为规划影响下,滇池流域土地利用总的发展比较稳定,人为因素、人工措施的实施比较合理。分维值能较好反映各土地利用类型复杂程度及稳定性。     

基于DEM的太湖流域水文特征提取

文章选取太湖流域作为研究对象,采用1：25万中比例尺DEM作为基础数据,应用ESRI公司开发的ArcGIS地理信息系统软件进行流域水文特征提取,得到了研究区域水流流向、汇流栅格生成、河网水系、子流域边界等流域特征信息,经与标准河流水系特征对照,认为基于DEM提取的太湖流域水文特征信息是合理的,可作为基础信息,为太湖流域生态环境治理实践及理论研究提供数据支撑。     

印染废水生化出水高锰酸钾强化混凝深度处理溶解性有机物的去除特性

采用高锰酸钾预氧化,强化某印染废水生化出水铁盐混凝深度处理溶解性有机物(DOM),考察了高锰酸钾强化混凝对印染废水生化出水中DOM的去除特性并为优化混凝深度处理工艺提供理论参考.在最优投加条件下,高锰酸钾强化混凝处理提高了DOM色度的去除效果,以美国染料生产协会色度值(ADMI7.6)表征时为84%,出水ADMI7.6值较单独混凝处理降低了43%.但以溶解性有机碳(DOC)表征时去除率基本保持不变,为55%.通过XAD-8/XAD-4吸附树脂分离技术和分子量分布分析发现,高锰酸钾强化混凝处理通过有效去除疏水性和弱疏水性DOM色度降低了出水的色度.同时,出水中亲水性和小分子DOM(MW<1 kDa)较单独混凝处理分别增加了34%和15%,导致了DOM去除率以DOC表征时无显著改善.采用三维荧光光谱技术定性分析表明,引起色度的可见类富里酸和类腐殖酸物质被进一步去除使出水色度降低,此时出水中增多的小分子亲水性DOM主要为类蛋白质和富里酸物质.因此,高锰酸钾强化混凝处理过程仍需与其它能去除亲水性、小分子量DOM(MW<1 kDa)的处理工艺结合,以提高总体去除效率.     

碲化镉量子点诱导氧自由基产生的检测

随着量子点(quantum dots,QDs)在生物标记和医学影像等领域的应用日益广泛,其环境暴露量逐渐增加,深入探讨QDs的毒性机制具有重要意义。QDs通过产生活性氧(ROS)诱发毒性效应是目前普遍接受的毒作用模式。为了探讨量子点的毒性与所诱发的ROS的种类和数量的关系,选用碲化镉量子点(CdTe QDs和CdTe/ZnS QDs),利用电子顺磁共振技术(EPR)分别测定了CdTe QDs和CdTe/ZnS QDs在无细胞体系中诱导ROS产生的种类和强度;利用EPR法、紫外可见分光光度法和荧光分光光度法分别测定了4、20和100nmol·mL-1的CdTe QDs和CdTe/ZnS QDs对超氧阴离子(·O2-)和羟基自由基(·OH)产生的促进作用。实验结果显示,CdTe QDs可诱导·O2-的产生;CdTe QDs和CdTe/ZnS QDs对·OH与·O2-的产生有明显的促进作用,且具有剂量-效应关系。研究表明,量子点可诱导和促进ROS产生,不同结构量子点对ROS的诱导和促进作用不同。     

Seed choice by rodents: learning or inheritance?

Learning plays a central role in animal life, and it has received special attention in the context of foraging. In this study, we have tested whether learning operates in seed choices by rodents using the Algerian mouse (Mus spretus) and Holm oak (Quercus ilex) acorns as a model. At the laboratory, those rodents captured in the field during the acorn fall period (experienced individuals) rejected weevil-infested acorns, presumably because of their lower energetic value. By contrast, rodents born in captivity and reared without any contact with acorns (naïves) predated weevil-infested acorns at similar rates than sound ones. After exposing naïves to infested and sound acorns during 15 days, they rejected infested acorns as the experienced individuals. In the field, predation on weevil-infested acorns was lower than on sound ones. Predation rates on infested acorns were lowest at the end of the acorn fall season, whereas predation rates of sound acorns increased along the same period. This might be explained by the improved ability to reject infested acorns because of the accumulated experience acquired by the initially naïve rodents along the acorn fall season. We show that learning shapes strongly seed choices by rodents, and it may be advantageous over inherited behaviors in variable unpredictable situations, such as acorn infestation rates that vary strongly between years and trees. We consider that the role of learning has to be taken into account in future studies on seed predation by rodents.     

Morphological diversity of Struvite crystals produced by Myxococcus Coralloides and Myxococcus Xanthus

We studied the morphological diversity of struvite crystals produced by Myxococcus coralloides and Myxococcus xanthus in different culture conditions. We discussed the similarities of these crystals with the struvite morphology studied previously following the theory of the periodic bond chains.     

Impact of environmental concentrations of beta-cypermethrin on the antioxidant system in the brain and liver of zebrafish (Danio rerio)

Beta-cypermethrin (beta-CYP) is a widely used pyrethroid pesticide, the extensive application of which may potentially cause damage to non-target organisms. To investigate the effect of beta-CYP on the antioxidant system of aquatic animals, adult zebrafish were exposed to environmentally relevant dosages (0.01, 0.1 and 1.0 μg/L) of beta-CYP. The activities of four antioxidant enzymes in zebrafish liver and brain tissue were tested after 7, 15 and 30 days of exposure. Our results showed that exposure of beta-CYP could induce different levels of increase in hepatic superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR) and glutathione peroxidase (GPx) activities at 7 and 15 days post exposure (dpe), but caused apparent inhibition of hepatic SOD, GR and GPx activities at 30 dpe. Unlike in liver tissue, SOD and CAT activities in zebrafish brain did not show any apparent response to beta-CYP during the whole treatment period. In addition, increased brain GPx activities were observed at 7 and 30 dpe.     

Occurrence and particle-size distributions of polycyclic aromatic hydrocarbons in the ambient air of coking plant

The purpose of this study was to characterize the occurrence and size distributions of ten species of polycyclic aromatic hydrocarbons (PAHs) in the ambient air of coking plants. Particulate-matter samples of four size fractions, including ≤2.1, 2.1–4.2, 4.2–10.2, and ≥10.2 μm, were collected using a Staplex234 cascade impactor during August 2009 at two coking plants in Shanxi, China. The PAHs were analyzed by a gas chromatograph equipped with a mass-selective detector. The concentrations of total particulate-matter PAHs were 1,412.7 and 2,241.1 ng/m³ for plants I and II, and the distributions showed a peak within the 0.1–2.1 μm size range for plant I and the 0.1–4.2 μm for plant II. The size distributions of individual PAHs (except fluoranthene) exhibited a considerable peak within the 0.1–2.1 μm size range in coking plant I, which can be explained by the gas–particle partition mechanism. The ambient air of the coking plant was heavily polluted by PAHs associated with fine particles (≤2.1 μm), and benzo[b]fluoranthene made the largest contribution to total PAHs. The exposure levels of coking-plant workers to PAHs associated with fine particles were higher than to PAHs associated with coarse particles. Benzo[b]fluoranthene, benzo[a]pyrene, and dibenzo[a,h]anthracene should be the primary pollutants monitored in the coking plant. This research constitutes a significant contribution to assessing the exposure risk of coking-plant workers and providing basic data for PAH standards for ambient air in coking plants.     

城市污水厂污泥高温好氧堆肥氮素转变行为研究

采用两段式高温好氧堆肥工艺 ,研究了污泥堆肥中氮素转变规律。研究表明 ,硝化作用受到温度和NH+ 4 N含量的影响显著。一次发酵中 ,堆料平均温度高于 4 0℃ ,硝化作用受到强烈抑制 ;二次发酵后期 ,由于NH+ 4 N浓度降低 ,故硝化过程减缓。不同调理剂及操作条件对氮素损失影响较大 ,利用腐熟堆肥作为调理剂可以减少氮素损失。适当降低堆料温度、增加初始含水率及适当减少初始挥发份含量等措施均可在一定程度上减少氮素损失