持久性有机污染物(POPs)研究进展

对持久性有机污染物的定义、特点、种类和危害进行了介绍,分析了这些物质在全球自然界中存在的量和来源,阐述了POPs在区域或全球的迁移、循环模式以及POPs的预测模型,提出了对目前和将来POPs控制的研究对策和一些意见。     

淘汰持久性有机污染物（POPs）最新进展

持久性有机污染物又称为难降解有机污染物（简称POPs），它是性质十分稳定，难于通过光降解的有机化合物。持久性有机污染物包括第一类有机氯农药，例如滴滴涕（DDT）、狄氏剂、毒杀芬和氯丹等，以及若干工业化学产品或副产品，如多氯联苯（PCBs）、二恶英和呋喃等。它们往往以卤化物形式在，具有低水溶性和高脂溶性，因而易于通过食物链浓缩，往往在（动物）脂肪内积累，它们还具有半挥发性，能够在大气中远距离传输。     

多氯联苯(PCBs)近期研究进展

对PCBs的理化特性、生产应用历史、污染现状以及近期的研究趋势作简要介绍.近期PCBs污染研究的趋势为1.由PCBs的总量测定到测定其同系物和异构体.2.迁移转化和行为研究受到充分的注意.3.PCBs降解的研究.4.广大区域内PCBs污染时空规律研究.     

全球总动员围剿POPs

POPs:持久性有机污染物 你听说过POPs吗?对普通公众来说,也许这是第一次。其实,臭名昭著的二恶英正是POPs家族的“形象代言人”。POPs是英文“persistent organic pollutants”的简称,意为持久性有机污染物。     

中美两国面向斯德哥尔摩公约的持久性有机污染物（POPs）控制决策管理和科学研究沟通研讨会

持久性有机污染物具有长期残留性、生物蓄积性 ,并可沿食物链传播 ,通过挥发和沉积在全球范围内迁移 ,已被国际社会视为必须立即采取行动的全球性环境问题 .中国政府已于 2 0 0 1年 5月 2 3日在瑞典首都斯德哥尔摩签署了《关于持久性有机污染物的斯德哥尔摩公约》 .作为化学品生产大国 ,中国在POPs的控制决策管理和科学研究方面仍面临巨大挑战 .控制POPs的行动需要科学家、决策者、企业界、非政府组织等各相关方的共同参与 ,因此需要建立科学研究和决策的信息沟通平台以改进POPs的控制行动 ,保障国家履约计划的实施 .针对以上问题 ,中国…     

果园土壤有机氯农药残留的时间趋势研究

以天然荒地和蔬菜基地作为对照 ,于 1993年和 2 0 0 3年对北京市某果园中具有不同树龄的老果园和新果园的土壤有机氯农药 (HCH ,DDT)残留情况进行了定位监测 .结果表明 ,在禁用 2 0年后 ,土壤中的有机氯农药残留水平大幅度降低 ,其中老果园的有机氯农药残留浓度显著高于新果园 (P <0 0 5 ) .果园土壤有机氯残留浓度显著高于荒地和蔬菜基地对照 (P <0 0 5 ) .DDT是当地主要的有机氯污染物 ,利用绿色食品生产基地环境质量标准作为评价标准对该果园土壤的污染程度进行了评估 .评估结果表明 ,新果园的土壤质量能够满足绿色食品生产的要求 ,老果园由于土壤中DDT和HCH残留超标严重不适合作为绿色食品生产基地     

我国杀虫剂类POPs污染场地的类型与污染控制对策分析

POPs污染场地作为潜在的POPs污染源,必须予以妥善管理。杀虫剂类POPs作为《斯德哥尔摩公约》首批的12种POPs物质中的绝大多数,其污染场地的管理是我国POPs污染场地管理的重点所在。本文分析了我国的杀虫剂类POPs污染场地的成因、类型、存在现状及管理现状,着重剖析了我国可适用于POPs污染场地的管理体系所存在的问题,在此基础上提出了加强我国POPs污染场地管理与控制的对策,指出了重点研究方向。     

POPs威胁人类远离有机污染物

今年5月23日是我国签署《关于持久性有机污染物的斯德哥尔摩公约》公约四周年的纪念日。如今，持久性有机污染物已成为人类面临的又一个严峻挑战。     

东海近岸持久性有机污染物分布及其影响因素

收集分析近10a东海近岸海水和沉积物中全氟烷基物(PFASs)、多氯联苯(PCBs)、多溴联苯醚(PBDEs)、有机氯农药(OCPs)、邻苯二甲酸酯(PAEs)和多环芳烃(PAHs)等六种典型持久性有机污染物(POPs)的分布及其影响因素的研究数据.结果表明,基于半数效应浓度(EC50)或海洋沉积物质量标准对海水和沉积物中POPs的生态风险评估,表明东海近岸大部分海域的PCBs、PBDEs和OCPs生态风险较低,但在杭州湾附近海域处于轻微至中等生态风险水平.PAHs整体上处于中等偏低及以下风险,PAEs处于中等偏高风险.PFASs处于中等及以下风险,但其中的全氟辛烷磺酸(PFOS)在长江口附近的生态风险较高.来自陆源输入的POPs在东海近岸海水和沉积物中的分布主要受到长江冲淡水、大气干湿沉降、沿岸流和潮汐作用的影响,呈现出绝大多数污染物含量在长江口和杭州湾附近较高,且向外海和南部沿岸总体降低的趋势.在浙闽沿岸泥质区、东海陆架泥质区,沉积物中部分污染物含量明显较高,与泥质区细颗粒泥沙对POPs的结合能力较强密切相关.长江冲淡水与东海海水交汇过程中温盐差异形成的“大陆边缘过滤器”效应,使得...     

浅谈持久性有机物的特性、危害及对策

持久性污染物对人类的生存威胁已经引起了国际社会的广泛关注。持久性有机污染物指的是持久存在于环境中,具有很长的半衰期,且能通过食物网积聚,并对人类健康及环境造成不利影响的有机化学物质。随着中国经济的发展,难降解的持久性有机物污染开始显现。国际上签署了〈关于持久性有机污染物的斯德哥尔摩公约〉,公约中确定了首批禁止使用12种持久性有机污染物。针对持久性有机污染物,详细介绍其分类、性质和危害,及中国采取的对策。     

Evaluation of phytoextracting cadmium and lead by sunflower, ricinus, alfalfa and mustard in hydroponic culture

Soil contaminated with heavy metals cadmium(Cd)and lead(Pb)is hard to be remediated.Phytoremediation may be a feasible method to remove toxic metals from soil,but there are few suitable plants which can hyperaccumulate metals.In this study,Cd and Pb accumulation by four plants including sunflower(Helianthus annuus L.),mustard(Brassica juncea L.),alfalfa(Medicago sativa L.), ricinus(Ricinus communis L.)in hydroponic cultures was compared.Results showed that these plants could phytocxtract heavy metals, the ability of accumulation differed with species,concentrations and categories of heavy metals.Values of BCF(bioconcentration factor)and TF(translocation factor)indicated that four species had dissimilar abilities of phytoextraction and transportation of heavy metals.Changes on the biomass of plants,pH and Eh at different treatments revealed that these four plants had distinct responses to Cd and Pb in cultures.Measurements should be taken to improve the phytoremediation of sites contaminated with heavy metals,such as pH and Eh regulations,and so forth.     

Oxidation of As(Ⅲ) by potassium permanganate

The oxidation of As(Ⅲ) with potassium permanganate was studied under conditions including pH, initial As(Ⅲ) concentration and dosage of Mn(Ⅶ). The results have shown that potassium permanganate was an effective agent for oxidizing of As(Ⅲ) in a wide pH range. The pH value of tested water was not a significant factor affecting the oxidation of As(Ⅲ) by Mn(Ⅶ). Although theoretical redox analyses suggest that Mn(Ⅶ) should have better performance in oxidization of As(Ⅲ) within lower pH ranges, the experimental results show that the oxidation efficiencies of As(Ⅲ) under basic and acidic conditions were similar, which may be due to the adsorption of As(Ⅲ) on the Mn(OH)2 and MnO2 resulting from the oxidation of As(Ⅲ).     

Distribution and ecological effect of mercury in Laogang landfill, Shanghai, China

Laogang landfill near Shanghai is the largest landfill in China, and receives about 10000 t of daily garbage per day, Samples of topsoil and plants were analyzed to evaluate mercury pollution from the landfill. For topsoil samples, there were significant correlations among total mercury （HgT）, combinative mercury （Hgc） and gaseous mercury （HgG）, and content of total organic carbon （TOC）, but, no significantly relationship was found between Hg content and filling time. Hg content changes in vertical profiles with time showed that the average Hgv of profiles 1992, 1996, and 2000 was similar, but their average HgG was quite different. HgT was significantly correlated with Hgc in profile 1992 and 2000, and Hgv was significantly correlated with Hg6 in profile 1996. HgG/Hgv ratio in profile samples decreased in the order of （HgG,/HgT）1992〉（HgG/HgT）1996〉〉（HgG/HgT）2000. A simple outline of Hg release in landfill could be drawn： with increasing of filling time, degradation undergoes different biodegradation, accordingly, gaseous mercury goes through small, more, and small proportion to total mercury. Distribution of Hg in plants was inhomogeneous, following the order of leaf〉root〉stem. The highest value of leaf may be associated with higher atmospheric Hg from landfill. Ligneous plants （e.g. Phyllostachys glanca, Prunus salicina and Ligustrum lucidum） are capable of enriching more Hg than herbaceous plants.     

EDTA-enhanced phytoremediation of lead contaminated soil by Bidens maximowicziana

Phytoremediation is a potential cleanup technology for the removal of heavy metals from contaminated soils.Bidens maximowicziana is a new Pb hyperaccumulator,which not only has remarkable tolerance to Pb but also extraordinary accumulation capacity for Pb.The maximum Pb concentration was 1509.3 mg/kg in roots and 2164.7 mg/kg in overground tissues.The Pb distribution order in the B. maximowicziana was:leaf>stem>root.The effect of amendments on phytoremediation was also studied.The mobility of soil Pb and the Pb concentrations in plants were both increased by EDTA application.Compared with CK(control check),EDTA application promoted translocation of Pb to overground parts of the plant.The Pb concentrations in overground parts of plants was increased from 24.23-680.56 mg/kg to 29.07-1905.57 mg/kg.This research demonstrated that B.maximowicziana appeared to be suitable for phytoremediation of Pb contaminated soil,especially,combination with EDTA.     

Decomposition of alachlor by ozonation and its mechanism

Decomposition and corresponding mechanism of alachlor, an endocrine disruptor in water by ozonation were investigated. Results showed that alachlor could not be completely mineralized by ozone alone. Many intermediates and final products were formed during the process, including aromatic compounds, aliphatic carboxylic acids, and inorganic ions. In evoluting these products, some of them with weak polarity were qualitatively identified by GC-MS. The information of inorganic ions suggested that the dechlorination was the first and the fastest step in the ozonation of alachlor.     

Enzymatic oxidation of aqueous pentachlorophenol

The influence of the nonionic surfactant Tween 80 on pentachlorophenol （PCP） oxidation catalyzed by horseradish peroxidase was studied. The surfactant was tested at concentrations below and above its critical micelle concentration （CMC）. Enhancement of PCP removal was observed at sub-CMCs. The presence of Tween 80 in the reaction mixture reduced enzyme inactivation which occurred through a combination of free radical attack and sorption by precipitated products. A simple first-order model was able to simulate time profiles for enzyme inactivation in the presence or absence of Tween 80. At supra-CMCs, the surfactant caused noticeable reductions in PCP removal, presumably through micelle partitioning of PCP which precluded the hydrophobic PCP molecule from interacting with the enzyme.     

Chlorobenzenes in waterweeds from the Xijiang River （Guangdong section） of the Pearl River

The Xijiang River is the major source of water for about 4.5 millions of urban population and 28.7 millions of rural population. The water quality is very important for the health of the rural population. The concentration and distribution of chlorobenzenes (CBs) in both water and waterweeds collected from 4 stations in the Xijiang River (Gangdong section) of the Pearl River in April and November were determined. The result showed that nearly every congener of CBs was detected. The total contents of CBs (∑CBs) in the river water ranged from 111.1 to 360.0 ng/L in April and from 151.9 to 481.7 ng/L in November, respectively. The pollution level of CBs in the water in April was higher than that in November. The contents of ∑ CBs in waterweeds ranged from 13.53×102 μg/g to 38.27×102μg/g dry weight (dw). There was no significant difference between April and November in waterweeds. The distribution of CBs in roots, caulis, and leaves of Vallisneria spiralis L. showed different patterns. The leaves mainly contained low-molecular-weight CBs(DCBs), whereas the roots accumulated more PCBs and HCBs. The average lgBCFlip (bioconcentration factor) of CBs ranged from 0.64 to 3.57 in the waterweeds. The spatial distribution character of CBs in the Xijiang River was: Fengkai County ＜ Yunan County ＜Yun'an County ＜ Gaoyao County according to the ∑CBs, and the pollution deteriorated from the upstream to the downstream of the Xijiang River. Further analysis demonstrated that the discharge of waste containing CBs may be the main source of CBs pollution in the Xijiang River.     

Degradation of 2,4-dichlorophenol with a novel TiO2/Ti-Fe-graphite felt photoelectrocatalytic oxidation process

Degradation of 2,4-dichlorophenol(2,4-DCP)was studied in a novel three-electrode photoelectrocatalytic(PEC)integrative oxidation process,and the factors influencing the degradation rate,such as applied current,flow speed of O_2,pH,adscititious voltage and initial 2,4-DCP concentration were investigated and optimized.H_2O_2 was produced nearby cathode and Fe~(2 )continuously generated from Fe anode in solution when current and O_2 were applied,so,main reactions,H_2O_2-assisted TiO_2 PEC oxidation and E-Fenton reaction,occurred during degradation of 2,4-DCP in this integrative system.The degradation ratio of 2,4-DCP was 93% in this integrative oxidation process,while it was only 31% in E-Fenton process and 46% in H_2O_2-assisted TiO_2 PEC process.So,it revealed that the degradation of 2,4-DCP was improved greatly by photoelectrical cooperation effect.By the investigation of pH,it showed that this integrative process could work well in a wide pH range from pH 3 to pH 9.     

Effect of copper on the degradation of pesticides cypermethrin and cyhalothrin

The influence of coexisting copper (Cu) ion on the degradation of pesticides pyrethroid cypermethrin and cyhalothrin in soil and photodegradation in water system were studied.Serial concentrations of the pesticides with the addition of copper ion were spiked in the soil and incubated for a regular period of time,the analysis of the extracts from the soil was carried out using gas chromatography (GC).The photodegradation of pyrethroids in water system was conducted under UV irradiation.The effect of Cu~(2 ) on the pesticides degradation was measured with half life (t_(0.5)) of degradation.It was found that a negative correlation between the degradation of the pyrethroid pesticides in soil and Cu addition was observed.But Cu~(2 ) could accelerate photodegradation of the pyrethroids in water.The t_(0.5) for cyhalothrin extended from 6.7 to 6.8 d while for cypermethrin extended from 8.1 to 10.9 d with the presence of copper ion in soil.As for photodegradation,t_(0.5) for cyhalothrin reduced from 173.3 to 115.5 rain and for cypermethrin from 115.5 to 99.0 min.The results suggested that copper influenced the degradation of the pesticides in soil by affecting the activity of microorganisms.However, it had catalyst tendency for photodegradation in water system.The difference for the degradation efficiency of pyrethroid isomers in soil was also observed.Copper could obviously accelerate the degradation of some special isomers.     

基于综合水质标识指数和对应分析法的校园河道水质评价

以三峡大学的校园河道求索溪为研究对象,利用综合水质标识指数法确定求索溪水质类别,分析其水质时空变化规律,并利用对应分析法得出求索溪中不同监测点的主要污染因子.研究结果表明:求索溪整体的综合水质标识指数为7.423,整体水质为劣V类(地表水环境质量标准GB 3838-2002)且黑臭.从时间变化来看,求索溪4月份的水质最差,5月份次之,4、5月份所有监测点的水质都劣于V类且黑臭;8月份水质最好,水质为Ⅳ类;从空间分布来看,8个监测点综合水质标识指数均超过6.0,水质为劣V类,其中6号监测点的水质相对最好,监测点3号的水质相对最差;对应分析法得出求索溪的整体水体污染程度受总氮因子的影响最大,其次为总磷.该研究拟为求索溪及类似校园河道的水环境治理研究提供基础依据和参考.