Photochemical degradation of six polybrominated diphenyl ether congeners under ultraviolet irradiation in hexane

The photodegradation of six individual PBDE congeners (BDE-28, 47, 99, 100, 153, 183) in hexane was investigated under UV light in the sunlight region, employing a mercury lamp filtered with Pyrex glass. All photodegradation reactions followed the pseudo-first-order kinetics, with the half-lives ranging from 0.26h for BDE-183 to 6.46h for BDE-100. The photochemical reaction rates of PBDEs decreased with decreasing number of bromine substituents in the molecule, also in some cases were influenced by the PBDE substitution pattern. Principal photoproducts detected were less brominated PBDEs, and no PBDE-solvent adducts were found. Consecutive reductive debromination was confirmed as the main mechanism for the photodegradation of PBDEs in hexane. In general, debromination firstly occurred on the more substituted rings, when the numbers of bromine atoms on the two phenyl rings were unequal. For less brominated PBDEs, the photoreactivity of bromines at various positions of phenyl rings decreased in the order: ortho>para; while for higher brominated PBDEs, the difference became not significant.     

Concentrations of chlorobenzenes, hexachlorobutadiene and heavy metals in surficial sediments of Kaohsiung coast, Taiwan

This work analyzes surface sediment samples collected from 40 stations along the Kaohsiung coast in southern Taiwan for chlorobenzenes (CBs), hexachlorobutadiene (HCBD) and heavy metals (Cu, Zn, Pb, Cd, Ni, Fe, Mn and Cr). The highest CBs concentrations are recorded in station T7-15 (about 10 km west off the outlet of Da-lin-pu ocean outfall pipe), with total di-, tri-, tetra-, penta- and hexa-chlorobenzenes concentrations of 290.5, 117.1, 64.5, 15.7 and 22.3 ng/g, respectively. The major pollution source of HCBD is most likely located in the Tso-yin ocean outfall field; while the Dah-lin-pu ocean outfall field and Kao-ping Chi estuary, located in the southern portion of Kaohsiung coast, are the major contributors of hexachlorobenzene. The concentration of CBs congeners correlate fairly well with each other, as do metals. However, concentrations of organics (CBs and HCBD) did not correlate with metals. This finding implies that the pollution characteristics of organics and heavy metals in this highly utilized coastal zone markedly differ from each other.     

“允许差值法”用于环境监测实验室分析质量控制

本文通过实验室间试验,确定分析方法的精密度和准确度,并经数学处理,把这二项指标以“允许差值”表示,应用”允许差值法”确定常规监测中平行双样减差值的允许范围,多次测定均值与靶值的减差值允许范围,加标百分回收率允许范围和控制样的受控范围,以此对分析质量进行控制。本方法反映了统一的分析质量要求,无需重复做质控图。     

双道氢化物原子荧光法测定水和土壤中的砷

用AFS-2201双道氢化物发生原子荧光法测定水、土壤样品中的砷含量,方法简捷、快速、准确,二次污染物少.HNO3浓度大于5ppm时,对测量结果有影响.主机通过与微机相联可直接得出监测数据,大大减轻了监测人员的工作量,测定结果令人满意.     

环境意识的较量——记津市市中学生环保知识竞赛

五月二十二日,兰苑宾馆大会议厅里热闹非凡,湖南省津市市首次中学生环境保护知识竞赛进入了高潮。五个学校的学生代表队锣鼓相当,互不示弱,几轮必答、抢答后出现平局,不得不加题抢答,经过近两个小时的角逐,决赛终于得出结果。津市一中代表队捧走了冠军,津市职业中专代表队和津市二中代表队夺得亚军,获第三名的是津市四中代表队和湘潭盐矿子弟学校代表队。由津市市教育委员会和津市市环境保护局联合举办的全市首次中学生环境保护知识竞赛,以“六·五”世界环境日《儿童与环境》为主题。得到了各学校领导的重视,老师的精心组织和耐心辅导,使参赛学生很快进入角色。津市市职业中专在收到通知后,校长、书记亲自召集教务处、政教处和     

贵州自然灾害对经济发展的影响及其防治对策

贵州地处云贵高原的东斜坡地带,地势起伏,高差悬殊。由于地质构造复杂,新构造运动强烈,表层岩体较为破碎;年降雨量集中,暴雨强度大;加之人为地对生态环境的严重破坏,导致多种自然灾害频繁发生和不断加剧。     

叶绿素检测方法

前言 近年来,叶绿素α在水质富营养化评价及大气污染评价方面起着越来越显著的重要作用。叶绿素在其它科学领域如植物光合作用、光电化学的研究中也有着非常重要的意义。因此,叶绿素的检测方法国外近年来研究较多。除了通常应用的分光光度法,萤光分析法外,还出现了薄层色谱、气相色谱、液相色谱等多种方法。国内     

津市市在乡镇环保监督员中实行目标管理责任制

湖南省津市市环境保护局为加强农村环境管理,从今年起,将目标管理责任制引入农村环境监督管理机制,制定了农村环境保护工作目标与考核办法,并已开始实施。津市市乡镇环境保护监督员是去年经市政府批准配备的。经过一年的工作实践,积累了一些经验,对农村环境建设起到积极促进作用。今年为适应改革需要,进一步强化农村环境监督管理,市环保局决定以农村环     

全面防范 消除隐患

作为国内厨卫行业一流品牌,长期以来,帅康集团十分重视系统的消防安全工作.公司成立了"防火安全委员会",由总裁任主任,主管副总任副主任,具体分管消防工作,安保科负责消防日常工作.     

随意倾倒疏浚物行为的法律性质

目前,我国大部分海域的环境状况良好,但是一些污染海洋的违法行为依然存在。如把海洋当成“垃圾桶”,任意倾倒废弃物,便是其中之一。例如1986年1月4日《中国环境报》登载了烟台港在疏浚时,曾将160万立方米的疏浚泥抛在港外,造成蛋岛附近水产养殖区的海参等水产资源严重受害。笔者带着这个问题,走访了国家海洋局环境管理司。得知发生这类事件,往往是由于人们对法律问题的认识比较模糊,分不清合法行为与违法行为的界限。人们把随意倾倒疏浚物看作是合法的,毋需承担任何法律责任。违法行为一般是指法律有明文规定而故意违反的