Voltammetric determination of the herbicide Bifenox in drinking and river water using a silver solid amalgam electrode

A new method for the determination of submicromolar and nanomolar concentrations of herbicide Bifenox using differential pulse voltammetry at a mercury meniscus modified silver solid amalgam electrode is described. This new type of working electrode is non-toxic, environmentally friendly, and compatible with principles of green analytical chemistry, and its surface can be easily electrochemically renewed in the case of passivation. The newly developed direct differential pulse voltammetric determination of Bifenox gives limit of determination 6.7·10^?7 and 6.9·10^?7?M in drinking and river water, respectively. Both the selectivity and the sensitivity can be further increased by preliminary separation and preconcentration using solid phase extraction. This combination enables to reach limit of determination 0.9?×?10^?9 and 1.5?×?10^?9?M for drinking and river water, respectively. Because of lower running and investment costs, this electroanalytical method can be used for large scale monitoring of possible water contamination with tested herbicide.     

贵阳市区地表灰尘重金属污染分析与评价

以贵阳市区为研究地点,采集了贵阳城区工业区、交通区、商业区、居民区、文教区、公园广场、对照区7个类别共80个采样点的地表灰尘,分析了地表灰尘重金属在不同区域的分布特征,并分析其可能来源。最后,应用潜在生态危害指数法对6个功能区（工业区、交通区、商业区、居民区、文教区、公共区）样品中重金属的潜在生态危害进行评价。结果表明：贵阳市地表灰尘重金属的平均质量分数均高于贵州省土壤环境背景值,Cd、As、Cu污染质量分数都超过4倍以上背景值水平,其余重金属污染水平大多处于1~3倍背景值水平。就单个重金属潜在生态危害系数平均值来看,地表灰尘的潜在生态危害最大的是Hg,其次是Cd,生态危害最低的是Cr。6个功能区生态危害水平均属于强生态危害水平,其中工业区和公共区生态危害水平最高。     

水生植物种植场磷素分布特征与植物吸收

研究了水生植物种植场水体、沉积物及植物的磷含量及分布特征,结果表明进水的P浓度高于V类水标准,水生植物种植区内的由于受到沉淀、吸附及植物吸收的影响,水体P浓度远低于进水,水体不同形态P与TP之间呈现良好的相关关系;沉积物的TP质量分数在335～672 mg.kg-1之间,表层沉积物P质量分数是影响底层沉积物P质量分数的主要因素之一,沉积物中的TP和IP、OP之间同样存在相关性;水生植物对P均具有较好的吸收富集能力,不同水生植物的迁移系数均在0.5以上,平均为0.82,其中的黄花蔺(Limnocharis flava)与欧慈菇(Sagittaria sagittifolia)显示对P的良好吸收和迁移能力。基于本次调查的水生植物P质量分数统计分析表明,95%的水生植物地上部P质量分数正常值范围在1 415～4 947mg.kg-1之间,而地下部的P质量分数正常值范围在2 178～5 702 mg.kg-1之间。     

DNDC模型对川中丘陵区稻田CH_4、N_2O排放的模拟对比分析

利用IKONOS高分辨率(1m)卫星遥感图,进行典型抽样和地形→土地利用→土地覆盖→综合信息提取的方法,选定了代表川中丘陵区类特征的四川省金堂县为研究区域,通过对研究区域中不同固定耕作制度下代表性田块的选取,于2005年5月—2006年5月对田块管理者进行作物田间管理、作物产出等农业生产实际情况调查和分析,进行土壤理化性状、水样的测定,并结合当地的气象资料,利用DNDC模型模拟川中丘陵区不同耕作制度下稻田温室气体的排放情况。结果表明:冬水田-水稻田(PF)水稻生长期CH4排放通量为2.24 kg.hm-2.d-1,占年排放量的80.73%;水稻生长期和冬闲期N2O通量分别为0.033和0.003 6 kg.hm-2.d-1,水稻生长期排放量为4.28 kg.hm-2,占年总排放量的83.59%。CH4和N2O排放量在水稻整个生季节存在明显的互为消长关系。油菜-小麦田(RR)水稻生长期CH4排放通量为1.16 kg.hm-2.d-1,是休闲期的20.71倍,水稻生长期CH4排放量占年排放量的90.48%;水稻生长期和非水稻生长期N2O排放通量分别为0.070和0.027 kg.hm-2.d-1,水稻生长期N2O...     

HgCl2对斑马鱼SOD,AChE酶活性和基因相对转录量的影响

以HgCl2为实验毒物,研究其对斑马鱼的毒性效应,经染毒后,分别在第1天和第7天取斑马鱼的肌肉测定超氧化物歧化酶(SOD)、乙酰胆碱酯酶(AChE)活性,半定量RT-PCR检测肌肉中乙酰胆碱酯酶、细胞色素P450(CYP 1A)和超氧化物歧化酶(Cu/Zn-SOD)基因的相对转录量.结果显示HgCl2对斑马鱼的毒性很强...     

Concentration and distribution characteristic of main toxic metals in suspended particle material in Nanjing reach, Changjiang River

Six stations in the lower reach region of Changjiang River within Baguazhou Island, Nanjing reach were chosen to investigate the toxic metals pollution characteristic in suspended particle material (SPM). SPM concentration, as well as reflectance spectroscopy characteristic, toxic metal concentrations, and lead isotopes of suspended particle material were studied. SPM concentrations were obtained from fluvial cross-sectional sampling near the surface (20 cm) and the study presents the cross-sectional averages. SPM concentrations varied around 170?C300 mg L^???1. Reflectance spectroscopy measurements differed from each other over each cross-section but no common pattern characterizing the cross-sectional behavior of the measurements was observed. The metal concentrations in the SPM decreased in the sequence: Mn > Zn > Cu > Cr > Pb > Cd. The result of lead isotopes analysis proved that lead isotopes composition in SPM are mainly produced by natural contributions and influenced by anthropogenic activity at the same time.     

Fire and Explosion Index calculation method incorporating classified safety measure credits

Based on an analysis of two methods for the modification of the F&EI for the DOW Guide, it is found that the effects of safety measures are not classified. Moreover, the efficiency of the measures is magnified to various degrees, as the positive impact of the loss reduction measures are applied to the rate reduction of the intrinsic hazard in the evaluated unit. For this reason, a modification method using classified safety measures is proposed, in which safety measures are classified into process protection measures and loss reduction measures. The calculation of the modified F&EI involves the credit factors of process protection measures, whereas the determination of the maximum probable property damage incorporates the loss reduction measures. This method could provide more reasonable reference data for hazard units because of its more objective and reasonable evaluation results.     

贵阳市生活垃圾处理现状与对策研究

贵阳市生活垃圾处理存在公众环保意识不强、垃圾处理方式单一、设施落后和资金不足等问题,可从加强宣传与垃圾处理技术研究、推进管理体制建设和制定法律法规等方面改善贵阳市生活垃圾处理现状,以全面落实各项政策,推进城市生活垃圾处理工作,促进城市可持续发展。     

提高材料利用率的有效途径

从运用数冲编程技巧、改进加工方案和改进结构设计三方面阐述了提高利用率的方法。     

可持续发展的给水工业系统分析

本文建立了给水工业的系统框架 ,分析了给水工业的宏观和中观系统结构及其内在关系 ,讨论了不同层次的系统对给水工业可持续发展的影响 ,为制定我国水工业发展的政策和管理体系提供了理论基础