基于PCT方法的京津冀冬季PM2.5重污染天气型分析

T模态斜交主成分分析法（PCT）分析的天气过程时间尺度越长,该算法的优势越明显,天气分型结果也更完整,可信度越高.利用京津冀地区2014年冬季-2019年冬季（每年12月-翌年2月）的环境监测资料,以区域平均PM_2.5日均值大于150 μg·m^-3为标准,筛选出72个京津冀地区PM_2.5重污染日,采用ERA5提供的0.25°×0.25°气象再分析资料,应用PCT算法将72个PM_2.5重污染日海平面气压场客观地分为高压前部型、锋前低压型、高压后部型、均压场型和弱低压型5种类型,分别占总PM_2.5重污染天数的34.72%、20.83%、16.67%、16.67%和11.11%.另外,对2017年2月12-16日京津冀地区PM_2.5重污染过程的分析表明,重污染天气过程中随着逐日天气型的演变,污染物浓度特征、近地面风场和大气污染物污染传输路径均发生相应变化.     

基于垂直加密观测的北京地区霾和沙尘复合污染形成条件分析

为了弄清蒙古气旋外围出现的霾和沙尘复合污染特征及其形成的关键气象条件,本研究利用多种遥感设备（增强型云高仪、风廓线雷达和微波辐射计等）垂直加密观测数据,结合大气主要污染物（PM₁₀、PM_2.5、SO₂、NO₂）监测数据、加密自动气象站观测数据,以及常规地面和高空气象观测数据、NCEP再分析数据等,分析发生在北京春季的2次霾和沙尘重污染过程.结果表明,2017年5月4—5日为一次PM₁₀和PM_2.5混合污染过程,与上游地区强烈发展的蒙古气旋后部风沙区的输送有关.上游地区因受中-低空西来槽影响上升气流加强,使沙尘细颗粒物（粒径≤10 μm）悬浮于空中,由中-低空偏西风输送至下游地区,被北京及附近的弱下沉气流带至地面造成严重的PM₁₀、PM_2.5混合污染.其中,地面偏西风对上游地区的PM₁₀、PM_2.5的水平输送作用明显;2018年3月27—28日凌晨是受蒙古气旋底部低压区辐合作用和偏南气流输送作用形成的积累型霾（PM_2.5）污染.28日凌晨2：00开始蒙古气旋后部沙尘区随东-西向冷高压南压而向南扩散.随后冷高压不断东移形成回流偏东风,偏东风使北京及西北部地区的低层大气产生辐合上升运动,导致本地尘土扬起,造成PM_2.5重污染和PM₁₀极严重污染;浮尘天气引发的大气污染具有突发性特征,且持续时间较长.边界层高度低、低层大气存在逆温层（或等温层）并长时间维持是霾和沙尘复合污染形成和持续的重要条件.霾和沙尘复合重污染的形成是人为污染物、沙尘细颗粒物水平和垂直输送,以及大气层结稳定共同作用的结果.     

长江中游地区PM2.5重污染过程的典型天气环流分型及区域传输影响

作为一个新的区域性霾污染中心,长江中游地区地理位置特殊,是我国中东部地区大气污染物区域传输的重要枢纽,天气环流对该区域不同传输和累积型PM_2.5重污染的形成机制还不甚了解.利用T-mode斜交旋转主成分分析法（PCT）,对2015~2019年采暖季长江中游地区74 d PM_2.5重污染事件进行天气环流分型,得到：PCT1高压底部传输型（天数：41 d,占比：55.4%）、PCT2低压辐合累积型（天数：12 d,占比：16.2%）、PCT3高压静稳累积型（天数：11 d,占比：14.9%）和PCT4高压后部传输型（天数：10 d,占比：13.5%）这4种主要的大气环流类型.区域传输型污染（PCT1和PCT4）占比高达69%,是长江中游地区PM_2.5重污染发生的主导因素,突显了地域特殊性.其中,PCT1是最主要的环流型,冷锋南侵伴随强偏北风驱动上游地区污染物快速传输,使得PM_2.5浓度暴发式增长.境内传输通道城市襄阳、荆门和荆州PM_2.5传输过程具有12 h滞后特征,其PM_2.5影响源区主要分布在上游的河南中北部、山东西部和华北大部分地区.PCT4传输型受低层偏东风输送影响,污染上升速率也相对较快.PCT2和PCT3为静稳天气环流型,地面风速较小,低层水平辐合和下沉运动有利本地PM_2.5重污染累积,污染上升速率和持续时间都相对传输型更长.     

2013年京津冀重污染特征及其气象条件分析

2013年中国东部地区多次发生持续的重霾污染事件.为探究其气象条件与重污染事件的关系,本文使用欧洲中心2013年东亚地区的逐日气象数据和北京、天津、石家庄的逐时PM_2.5浓度数据以及2013年MICAPS观测数据,分析了重污染事件对应的天气形势,并使用NAQMPS针对2013年1月的重污染事件进行情景模拟.研究结果表明：1北京、天津和石家庄地区PM_2.5浓度,夏秋季节日变化不显著,秋冬季节白天低夜间高;3地PM_2.5浓度均表现为12-1月浓度最高,7月最低;.2500 hPa平直西风气流,850 hPa弱暖平流,地面处于弱高压后部或高压底部高低空配置下的天气系统,对应着重污染事件的高发期;3源强不变的情况下,京津冀地区由弱高压前部控制转为弱高压控制时,地面温度升高0~5℃,相对湿度增加30%~50%,风速下降2~3 m·s^-1,PM_2.5浓度变化可达300 μg·m^-3.     

2018年冬季南京重霾污染特征及气象因素分析

2018年11月底—12月初南京及周边地区发生一次大范围持续性霾污染,利用南京市空气质量监测资料、颗粒物成分逐时观测资料、南京站探空资料等,结合天气学诊断分析、后向轨迹模拟和聚类分析等方法,分析此次重霾事件的污染特征和气象因素.结果表明,此次重霾事件具有峰值浓度高、持续时间长、波动较明显等特点.污染时段PM_2.5浓度变化分为3个阶段,平均浓度为114.7 μg·m^-3,整体达到中度污染.重霾期间南京市大气环境处于富氨条件,颗粒物整体偏酸性,移动源排放比重高于固定源,PM_2.5主要成分的存在形式为硫酸铵、硝酸铵和其他硝酸盐.本次重霾事件中气象条件对污染物的输送和累积影响显著,在PM_2.5浓度极端事件发生期间,均有各气象要素与PM_2.5浓度同步变化.高PM_2.5浓度与对流层低层增暖增湿、弱的西南风相对应.重霾事件的主要天气成因是冬季东部地区出现大面积稳定且持久的均压场,南京及周边地区近地面中高层污染物主要由西北和华北地区输送而来,低层污染物主要来自于本地源排放累积.动力条件和热力条件的相互配合,近地面受高压影响形成暖平流逆温层,且易形成下沉气流,使重霾天气持续发展.     

武汉地区2014年PM2.5时空分布与来源贡献的数值模拟研究

利用耦合了污染源在线追踪模块的化学传输模式NAQPMS （Nested Air Quality Prediction Model System）,结合地面细颗粒物（PM_2.5）的小时观测数据,模拟了2014年1、4、7、10月4个月份武汉地区PM_2.5浓度时空分布特征,量化了本地、武汉城市圈及远距离地区对武汉PM_2.5浓度贡献.研究发现,2014年武汉市PM_2.5年均浓度为85.3 μg·m^-3,污染天（PM_2.5日均值≥75 μg·m^-3）占全年总天数的47.9%.细颗粒物的月均值呈现出季节性特征,即冬季污染最为严峻,1月均值为199.1 μg·m^-3,PM_2.5浓度超标持续一整月;夏季空气质量最好,春秋介于两者之间.模拟的PM_2.5平均浓度在空间上大致呈现"城区高,郊区低"的分布态势.污染物区域来源解析发现,武汉市本地排放源贡献在1月最低,为34.1%,表明外来源贡献对长期灰霾的形成起决定性作用.7月本地源影响最显著（65.7%）,和毗邻城市源（23.1%）一起成为夏季污染物的主要来源.4月和10月本地排放贡献比分别为49.1%和42.1%.4个月份,武汉城市圈对该市PM_2.5浓度的贡献差异不大,范围在20.8%~24.1%.受大尺度天气系统的影响,远距离传输贡献率趋势与本地来源相反,占10.6%~35.3%.研究结果表明污染气团跨界输送对武汉不同季节PM_2.5浓度有重要贡献.在冬季大范围污染背景下,污染物区域大范围协同控制才能有效减缓武汉PM_2.5污染问题;而夏季对本地及近周边城市的减排措施可以有效改善武汉的空气质量.     

天津市夏秋季O3-PM2.5复合污染特征及气象成因分析

天津市PM_2.5-O₃复合污染主要发生在夏秋季,本研究筛选出2017年夏季一次和秋季两次典型PM_2.5-O₃复合污染过程,系统分析污染物变化特征,探究天气形势和主要气象因子的影响.结果表明,3次污染过程PM_2.5与O₃呈现不同程度的正相关性（日均值相关系数达到0.34~0.78）,O₃与PM_2.5中硫酸盐和有机碳日均浓度存在较为一致的变化趋势.与非复合污染日相比,复合污染日无机盐占PM_2.5组分的比重增加,增长率为1.9%~7.3%;而碳组分占比减小.复合污染过程发生时,天津地区处于低压槽前或高压后部,近地面弱的偏南风辐合造成较差的大气扩散条件,导致大气污染物的累积.研究结果发现,夏季和秋季PM_2.5-O₃复合污染过程需要适宜的气象条件,温度阈值分别为25~35℃和20~30℃,相对湿度分别为40%~70%和55%~100%.夏秋季复合污染过程关键无机组分及其形成机制有所差异.夏季,日间O₃等强氧化剂对SO₂的气相氧化过程和夜间高湿条件（大约60%）下液相化学反应可能是主导的化学机制,硫酸盐增长率为8.2%.秋季高湿环境（≥80%）不仅促进SO₂向硫酸盐转化,秋季第一次复合污染过程硫酸盐增长4.7%,也促进夜间N₂O₅水解反应等,秋季第二次复合污染过程硝酸盐增长6.0%,两种机制成为秋季复合日PM_2.5显著增长的关键机制.本研究揭示了驱动天津市PM_2.5-O₃复合污染过程发生的适宜气象条件、PM_2.5关键化学组分及其化学过程,为复合污染的成因及协同控制提供了参考.     

稳定天气形势下京津冀和长三角地区重度污染过程气象成因解析

基于空气质量数据、天气图、常规地面气象观测数据、秒探空资料以及高分辨率的降水数据，剖析了2015年12月19—27日发生在我国东部地区的一次大范围重度污染过程的特征及成因.结果表明，此次污染过程中，我国东部地区主要受到东路冷高压、均压场以及西路冷高压的影响，在东路冷空气及均压场的影响下，BTH（Beijing-Tianjin-Hebei）地区污染物不断累积，西路冷空气影响下污染物浓度开始降低，YRD（Yangtze River Delta）地区在稳定的均压场下污染物不断累积.污染期间，BTH及YRD近地层均有逆温现象发生，且逆温层越厚、强度越大，污染越重.此外，较低的近地面风速、较高的相对湿度，亦不利于污染物的扩散稀释，导致此次重度污染事件的发生和持续.YRD地区在重度污染发生时，有降水现象发生，导致YRD地区PM_2.5浓度呈现波动性变化.     

2013—2015年北京污染频发期细颗粒物重污染成因与天气形势关系的研究

我国重污染呈现愈演愈烈态势,重污染事件在供暖季节（污染频发期）尤为频发.本文利用北京2013—2015年采暖期逐小时PM_2.5浓度数据、再分析资料、气团后向轨迹、气溶胶雷达数据以及探空数据综合分析了北京地区重污染状况,概括了重污染发生时常见的天气形势,探讨了重污染形成原因与天气形势的关系.研究结果表明：2013—2015年采暖期北京发生重污染（日均PM_2.5浓度大于150 μg·m^-3）的天数分别为36、28及35 d,即北京采暖期21.9%的天数受重污染天气影响.2月份重污染事件最为频发,发生频次为27.3%.北京发生重污染事件时,地面被高压控制时,高空500 hPa多东移的槽脊,当位于脊后槽前时,为上升运动,西南风,850 hPa多暖平流,西南风输送暖湿气流,湿度较大,地面偏南风,可能会存在污染物的输送;地面为低压控制时,500 hPa一般为稳定的西风气流或西北气流,低空850 hPa可能存在暖平流,地面常伴随弱的风场辐合,导致污染物累积;当地面为均压场时,高空500 hPa多为脊后槽前的形势,低空无明显冷暖平流,地面等压线稀疏或无等压线,静风天气.这3类结构引发的重污染天数分别占总重污染天数的47.3%、18.2%及34.5%.进一步分析重污染成因与天气形势关系表明：北京地面受高压系统控制时,污染时间持续最长,也最为频发（47.3%）,PM_2.5平均浓度最高可达258.8 μg·m^-3,且常伴随来自西南方向的污染物输送,北京上空1 km附近存在逆温和逆湿.对污染传输路径研究发现：主要存在3条输送通道,①天津-廊坊-北京、②沧州-廊坊-北京、③石家庄-保定-北京.鉴于目前数值模式对天气形势的预报较为成熟,本文对区域重污染过程与天气形势之间的关系研究,有助于为北京地区空气质量的精准预报预警提供科学支持.     

西南涡对四川盆地PM2.5污染的影响研究

利用2015—2016年西南涡个例数据与同期的细颗粒物（PM_2.5）浓度数据进行时空匹配,对比分析西南涡过境前后四川盆地PM_2.5浓度变化,并结合温度、湿度、风等气象要素及逆温特征,深入研究西南涡对PM_2.5污染的影响机理.结果表明：①2015—2016年四川盆地共182个西南涡,其中,干涡72个（多集中在春季）,弱降水涡75个（多集中在春季和冬季）,强降水涡35个（多集中在夏季）.②总体而言,干涡过境使四川盆地PM_2.5浓度增加,降水涡使PM_2.5浓度减小,强降水涡的削减作用强于弱降水涡.全年来看,干涡过境使四川盆地PM_2.5浓度增加10.52%,强、弱降水涡过境分别使PM_2.5浓度减小29.72%、9.71%.③除降水外,3类西南涡对PM_2.5影响的主导气象要素和逆温条件为相对湿度、风速和逆温层底高.而主导季节差异的气象要素和逆温条件各异：干涡的主导因素是温度垂直变化和逆温强度,在温度随高度递减和逆温强度较小的春季和夏季,对PM_2.5浓度的增幅减小（甚至有削减作用）;弱降水涡的主导因素是湿度和风速、逆温强度和逆温层厚度,春季其过境时湿度和风速最小,逆温强度和逆温厚度仅次于冬季,甚至使PM_2.5浓度增加;强降水涡的主导因素是风速、湿度和逆温层底高,夏季其过境时风速和低层湿度最小,逆温层底高最低,对PM_2.5的削减作用远弱于其他季节.     

Toxic effects of acetochlor, methamidophos and their combination on nifH gene in soil

Toxic effects of two agrochemicals on nifH gene in agricultural black soil were investigated using denaturing gradient gel electrophoresis （DGGE） and sequencing approaches in a microcosm experiment. Changes of soil nifH gene diversity and composition were examined following the application of acetochlor, methamidophos and their combination. Acetochlor reduced the nifH gene diversity （both in gene richness and diversity index values） and caused changes in the nifH gene composition. The effects of acetochlor on nifH gene were strengthened as the concentration of acetochlor increased. Cluster analysis of DGGE banding patterns showed that nifH gene composition which had been affected by low concentration of acetochlor （50 mg/kg） recovered firstly. Methamidophos reduced nifH gene richness that except at 4 weeks. The medium concentration of methamidophos （150 mg/kg） caused the most apparent changes in nifH gene diversity at the first week while the high concentration of methamidophos （250 mg/kg） produced prominent effects on nifH gene diversity in the following weeks. Cluster analysis showed that minimal changes of nifH gene composition were found at 1 week and maximal changes at 4 weeks. Toxic effects of acetochlor and methamidophos combination on nifH gene were also apparent. Different nifH genes （bands） responded differently to the impact of agrochemicals： four individual bands were eliminated by the application of the agrochemicals, five bands became predominant by the stimulation of the agrochemicals, and four bands showed strong resistance to the influence of the agrochemicals. Fifteen prominent bands were partially sequenced, yielding 15 different nifH sequences, which were used for phylogenetic reconstructions. All sequences were affiliated with the alpha- and beta-proteobacteria, showing higher similarity to eight different diazotrophic genera.     

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.     

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.     

Arsenic uptake by arbuscular mycorrhizal maize （Zea mays L.） grown in an arsenic-contaminated soil with added phosphorus

The effects of arbuscular mycorrhizal (AM) fungus (Glomus mosseae) and phosphorus (P) addition (100 mg/kg soil) on arsenic (As) uptake by maize plants (Zea mays L.) from an As-contaminated soil were examined in a glasshouse experiment.Non-mycorrhizal and zero-P addition controls were included.Plant biomass and concentrations and uptake of As,P,and other nutrients,AM colonization,root lengths,and hyphal length densities were determined.The results indicated that addition of P significantly inhibited root colonization and development of extraradical mycelium.Root length and dry weight both increased markedly with mycorrhizal colonization under the zero-P treatments,but shoot and root biomass of AM plants was depressed by P application.AM fungal inoculation decreased shoot As concentrations when no P was added,and shoot and root As concentrations of AM plants increased 2.6 and 1.4 times with P addition,respectively.Shoot and root uptake of P,Mn,Cu,and Zn increased,but shoot Fe uptake decreased by 44.6%,with inoculation, when P was added.P addition reduced shoot P,Fe,Mn,Cu,and Zn uptake of AM plants,but increased root Fe and Mn uptake of the nonmycorrhizal ones.AM colonization therefore appeared to enhance plant tolerance to As in low P soil,and have some potential for the phytostabilization of As-contaminated soil,however,P application may introduce additional environmental risk by increasing soil As mobility.     

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.     

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.     

Degradation of metabolites accumulated of benzo[a]pyrene by coupling Penicillium Chrysogenum with KMnO4

Several main metabolites of benzo[a]pyrene （BaP） formed by Penicillium chrysogenum, Benzo[a]pyrene-1,6-quinone （BP 1,6- quinone）, trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene （BP 7,8-diol）, 3-hydroxybenzo[a]pyrene （3-OHBP）, were identified by high-performance liquid chromatography （HPLC）. The three metabolites were liable to be accumulated and were hardly further metabolized because of their toxicity to microorganisms. However, their further degradation was essential for the complete degradation of BaP. To enhance their degradation, two methods, degradation by coupling Penicillium chrysogenum with KMnO4 and degradation only by Penicillium chrysogenum, were compared; Meanwhile, the parameters of degradation in the superior method were optimized. The results showed that （1） the method of coupling Penicillium chrysogenum with KMnO4 was better and was the first method to be used in the degradation of BaP and its metabolites; （2） the metabolite, BP 1,6-quinone was the most liable to be accumulated in pure cultures; （3） the effect of degradation was the best when the concentration of KMnO4 in the cultures was 0.01% （w/v）, concentration of the three compounds was 5 mg/L and pH was 6.2. Based on the experimental results, a novel concept with regard to the bioremediation of BaP-contaminated environment was discussed, considering the influence on environmental toxicity of the accumulated metabolites.     

Impact of atrazine and nitrogen fertilizers on the sorption of chlorotoluron in soil and model sorbents

Sorption of chlorotoluron in ammonium sulfate, urea and atrazine multi-solutes system was investigated by batch experiments. The results showed application of nitrogen fertilizers to the soil could affect the behavior of chlorotoluron. At the same concentration of N, sorption of chlorotoluron decreased as the concentration of atrazine increased on the day 0 and 6 in soil, respectively. The sorption of chlorotoluron increased from 0 to 6 d when soils were preincubated with deionized water, ammonium sulfate and urea solution for 6 d. That indicated incubation time was one of the most important factors for the sorption of chlorotoluron in nitrogen fertilizers treatments. The individual sorption isotherms of chlorotoluron in rubbery polymer and silica were strictly linear in single solute system, but there were competition sorption between pesticides or between pesticides and nitrogen fertilizers. That indicated the sorption taken place by concurrent solid-phase dissolution mechanism and sorption on the interface of water-organic matter or water-mineral matter.     

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.     

Potential of plant polyphenol oxidases in the decolorization and removal of textile and non-textile dyes

In this study an effort has been made to use plant polyphenol oxidases; potato （Solanum tuberosum） and brinjal （Solanum melongena）, for the treatment of various important dyes used in textile and other industries. The ammonium sulphate fractionated enzyme preparations were used to treat a number of dyes under various experimental conditions. Majority of the treated dyes were maximally decolorized at pH 3.0. Some of the dyes were quickly decolorized whereas others were marginally decolorized. The initial first hour was sufficient for the maximum decolorization of dyes. The rate of decolorization was quite slow on long treatment of dyes. Enhancement in the dye decolorization was noticed on increasing the concentration of enzymes. The complex mixtures of dyes were treated with both preparations of polyphenol oxidases in the buffers of varying pH values. Potato polyphenol oxidase was significantly more effective in decolorizing the dyes to higher extent as compared to the enzyme obtained from brinjal polyphenol oxidase. Decolorization of dyes and their mixtures, followed by the formation of an insoluble precipitate, which could be easily removed simply by centrifugation.