桂林市不同功能型公园水体微塑料的分布特征及风险评估

城市公园水体环境容量小,自净能力差,更容易受微塑料影响而造成水体微生态系统的失衡.以公园的功能特点(综合型、社区型和生态型)为基础,通过现场采样、显微观察和傅里叶红外光谱等方法,调查了桂林市公园水体微塑料的分布特征,并采用微塑料风险指数(H)和负荷指数(PLI)评估了微塑料的污染风险.结果表明,公园表层水和沉积物中微塑料的丰度范围分别为104.67～674.44 n·m^-3和95.57～877.78 n·kg^-1.微塑料形状主要包含碎片、纤维、薄膜和颗粒,且以小于1 mm的碎片和纤维为主.微塑料聚合物有聚乙烯和聚对苯二甲酸乙二醇酯.不同功能公园水体的微塑料丰度差异性显著,其中综合型公园的微塑料丰度最高.公园水体微塑料丰度与公园功能和入园人数密切相关.公园表层水的污染风险较低,而沉积物的污染风险相对较高.研究表明,旅游是桂林城市公园水体微塑料污染的重要来源,桂林市公园水体中微塑料污染风险总体属于轻度污染,但仍需关注其在城市小型淡水水域中的累积风险.     

微塑料在淀山湖水环境的污染分布、组成特征和生态风险

河流和湖泊是微塑料从陆地向海洋传输的重要渠道,是受人类活动和物质运输影响的重要区域.为研究微塑料在淀山湖地表水中的赋存特征和潜在风险,对淀山湖18个采样点表层水的微塑料丰度、形态、粒径、颜色和聚合物类型进行分析.结果显示,表层水中微塑料的丰度为575～5375 n·m^-3,平均为（1960±1085）n·m^-3.位于近生活区采样点的微塑料丰度(（2490±1260）n·m^-3)显著高于风景区(（1540±1280）n·m^-3)和农田区(（1170±430）n·m^-3),另外,出湖口采样点的微塑料丰度(（3570±2160）n·m^-3)显著高于入湖口(（2120±580）n·m^-3)及其他位置(（1500±730）n·m^-3),表现出明显的空间分布差异.纤维是最常见的微塑料形态（88.04%）;小粒径（<0.5 mm）及黑色微塑料占据主导地位,分别占比56.42%及57.86%;聚对苯二甲酸乙二醇酯（Poly...     

北京城市河流河水和沉积物中微塑料的组成与分布

微塑料已经被证实广泛存在于自然环境中,对生物和人类造成潜在危害,进行微塑料的赋存调研有助于了解城市河流河水和沉积物中微塑料的污染现状.以北京市北运河和怀河作为研究区域,共布设了8个水样点位和3个沉积物点位,研究并对比了北运河河水和沉积物以及怀河河水中微塑料丰度、粒径、颜色、形状和种类的组成与分布特征.结果表明,北运河河水中的微塑料丰度为(1 941±201)～(8 155±1 781) n·m^-3(n表示微塑料个数),平均丰度为4 160 n·m^-3;北运河沉积物中的微塑料丰度为(120±11)～(268±31) n·kg^-1.怀河河水中的微塑料污染程度低于北运河河水,微塑料的平均丰度为2 357n·m^-3.北运河上游河水和沉积物中微塑料的丰度高于下游,具有较明显的空间分布特征;怀河河水中的微塑料分布总体上无明显差异,但相距较远的两点位中微塑料的丰度之间具有显著差异.粒径、颜色和形状的分类统计结果显示,所有点位中微塑料的主要粒径区间为<300μm;白色/透明微塑料(50.75%～83.91%)...     

城市河道表层水及沉积物中微塑料的污染现状与污染行为

河流是微塑料从陆地向海洋传输的关键路径,在近年来得到了越来越多的研究重视.但实际上,目前关于城市不同区域河道表层水及沉积物中微塑料的污染现状及污染行为研究仍十分有限,相关问题依然不甚清晰.本文以上海市中心城区及郊区城镇区域的8条河道作为研究对象,共采集16个河道表层水及沉积物样品,采用高速摄像仪和傅立叶红外变换光谱仪鉴定样品中微塑料的丰度、尺寸、颜色、形状和类型等特征.结果表明,上海市城市河道表层水中微塑料的平均丰度为(7.5±2.8)个·L^-1,而沉积物中微塑料的平均丰度(以湿重计)则达到了(1 575.5±758.4)个·kg^-1.微塑料尺寸越小丰度越高.其中,低于500μm、纤维状、透明色和聚酯类的微塑料始终在上海市城市河道中占据主导地位,但沉积物中的微塑料分布更具多样性.相对于国内外其他城市河道中的微塑料污染,上海市城市河道中的微塑料污染较为严重.不同城市河道中,微塑料的形状和聚合物类型分布受到来源(主要为洗衣废水、个人护理产品和塑料废弃物等)、水动力学条件和本身理化性质等各种因素的较大影响.还进一步讨论了城市河道中微塑料的污染行为(...     

可可西里特拉什湖中微塑料污染特征、来源和生态风险

微塑料作为一种新型污染物，近年来已成为环境科学的研究热点.为探究青藏高原无人环境中的微塑料污染，以可可西里自然保护区特拉什湖作为研究区域，分析了湖滨沉积物中微塑料的丰度分布、物理形貌和成分特征.在此基础上，讨论了微塑料的潜在来源，并利用污染负荷指数(PLI)模型和风险指数(H)模型评估了微塑料的生态风险.结果表明，特拉什湖沉积物中微塑料丰度范围为39.58～247.92 n·m^-2，平均丰度为(107.08±101.34) n·m^-2.这一结果可作为现阶段微塑料污染研究的自然背景参考值.纤维占微塑料总数的79.49%，透明和小粒径(<1 mm)的微塑料占很大比例，确定的主要聚合物是聚酯(51.28%).纺织品是特拉什湖微塑料的主要来源，可能来自特拉什湖以西，通过大气环流长距离运输至该区域.生态风险评估模型显示，特拉什湖的微塑料污染负荷较轻；尽管少数点位的生态风险指数较高，但总体上该区域的微塑料污染仍处于较低水平.     

白洋淀上覆水及沉积物中微塑料赋存特征

为探究我国白洋淀淡水环境中微塑料的赋存特征,于2021年10月通过野外采样、实验室预处理、显微镜观察和激光红外光谱测定等方法鉴定了淀区10份上覆水及10份沉积物样品中微塑料的丰度分布、形状、粒径和聚合物类型,并通过Stokes沉降公式研究了微塑料在上覆水-沉积物界面的沉降规律,对其污染特征及潜在来源进行分析.结果表明,淀区上覆水及沉积物中微塑料丰度范围分别为474～19 382 n·m^-3和95.3～29 542.5 n·kg^-1,平均值为6 255.4 n·m^-3和11 088 n·kg^-1.上覆水中的微塑料主要聚合物为聚对苯二甲酸乙二醇酯[PET,(17.20±0.26)%],沉积物中微塑料以氯化聚乙烯[CPE,(46.11±1.30)%]为主.淀区内微塑料的沉降速度从0.079 3～111.754 7 mm·s^-1不等,粒径大的颗粒沉降速度较高,易沉降并保留在沉积物中.研究区微塑料污染主要来源为洗涤废水产生的纺织纤维排放,船舶漆、船舶橡胶和建筑材料磨损等过程.     

香溪河流域微塑料的分布特征及其迁移规律分析

微塑料作为水体中一种普遍存在的污染物已引起社会的广泛关注.为探究微塑料在淡水河流中的时空分布特征及其迁移规律,以长江支流香溪河为例,分别在2020年11月和2021年4月对香溪河表层水体、沉积物和消落带进行取样分析.结果表明,香溪河表层水体中微塑料的平均丰度为（6.64±1.32）n·L^-1（平水期）和（5.00±1.07）n·L^-1（枯水期）,沉积物中微塑料的平均丰度为（0.56±0.13）n·g^-1（平水期）和（0.41±0.09）n·g^-1（枯水期）,消落带中微塑料的平均丰度为（0.53±0.15）n·g^-1（平水期）和（0.68±0.18）n·g^-1（枯水期）,表层水体、沉积物和消落带中微塑料丰度分布存在显著差异性（P<0.05）.在表层水体和沉积物中微塑料粒径主要分布在0.1～0.5 mm,消落带中主要分布在1～5 mm;表层水体和消落带中微塑料颜色以透明为主,沉积物中以蓝色为主;香溪河流域微塑料的形态以纤维为主,材质主要是聚乙烯（PE）和...     

典型城市河网沉积物微塑料时空分布特征

微塑料是近年来广受关注的一类新污染物.淡水系统沉积物作为微塑料重要的汇,能反映出当地微塑料的长期污染水平.为探究典型城市河网沉积物中微塑料的时空分布特征,于2018年12月和2019年6月在望虞河西岸河网区分别采集了17个采样点的沉积物样品,使用体视显微镜和显微傅立叶变换红外光谱仪对微塑料进行形态观察以及成分鉴定.结果表明,微塑料的平均丰度(以dw计)为323.37 n·kg^-1,形状主要为碎片和纤维,颜色以黑色和蓝色为主,粒径主要分布在50～500μm之间,成分以PET、PE、PVE、PS和PP为主.夏季微塑料的丰度低于冬季,河网区上游地区微塑料的丰度高于中游和下游地区,最高丰度出现在污水处理厂的出水口采样点,沉积物中微塑料的丰度与表层水中微塑料的丰度无显著相关性.应用正定矩阵因子分解(PMF)模型解析微塑料的来源,发现微塑料的主要来源有农用塑料薄膜、生活废水、塑料垃圾以及工业生产.研究可为典型城市河网微塑料污染防控提供支撑.     

骆马湖表层沉积物微塑料的分布、来源及储存量

为探求骆马湖表层沉积物微塑料的分布特征,于2019年夏季和2021年冬季收集了20个采样点的样品,使用光学显微镜观察微塑料特征并分类,使用傅里叶变换红外显微镜光谱仪鉴定其聚合物成分,使用扫描电子显微镜分析其表面形态.结果表明,骆马湖夏季和冬季沉积物微塑料的丰度平均值为（513±201） n·kg^-1和（528±263） n·kg^-1.总体而言,60～500μm、纤维、透明和聚乙烯微塑料占比最高,表层沉积物微塑料的储存量分别为111.20 t（9月）和74.16 t（1月）.结果发现,夏季人工泄洪后,闸后小尺寸微塑料的比例均高于闸前30%以上,证明水流剪切力是加速微塑料破碎的驱动力.开始调水后,上游的微塑料丰度平均值从705 n·kg^-1下降到653 n·kg^-1,而下游则从530 n·kg^-1增加到740 n·kg^-1.上游沉积物中消失的是较小和较轻的塑料颗粒,如聚乙烯和聚丙烯.它们随着水流在上游表层沉积物中再悬浮,迁移至下游,并再次沉降.通过探讨人工泄洪...     

连云港海州湾海域表层水体和沉积物中微塑料的分布特征

近年来,微塑料成为国内外广泛关注的新型海洋污染物,海湾作为人类在海岸环境中的主要活动地区,一直是海洋污染物聚集地,但我国对近岸大部分中小型海湾环境中微塑料的分布状况仍鲜见报道.为了解我国近岸中小型海湾的微塑料污染特征,本研究以江苏省海州湾海域表层海水和沉积物中采集的微塑料为样本,通过定性和定量方法研究了表层水和沉积物中微塑料主要类型和丰度及空间分布特征.结果表明,海州湾表层水体和沉积物中的微塑料丰度分别为(2.60±1.40)个·m~(-3)和(0.33±0.26)个·g~(-1),在国内近岸环境(表层水0.33～545.00个·m~(-3),沉积物0.07～2.58个·g~(-1))中,海州湾表层水中的微塑料丰度处于较低水平,但沉积物中的微塑料处于较高水平.塑料污染物的粒径大小在水体中分布范围为0.08～13.48 mm,其中,微塑料(粒径5 mm)占91.8%,塑料污染物在沉积物中粒径的分布范围为0.04～14.74 mm,微塑料占91.4%,水体和沉积物中60%以上的微塑料粒径小于2.00 mm.海州湾海域微塑料的形态以纤维状为主,占92%;颜色以蓝色和黑色为主,占70%;材质以人造纤维和PET为主,占79.4%.表层水中微塑料的分布与悬浮物浓度分布具有显著的相关性(P0.05),沉积物中微塑料的分布受多方面因素影响,其分布规律与表层水中微塑料的分布以及沉积物中粒径的分布都具有较大差异性.通过对微塑料的形态特征以及成分组成的分析表明,海州湾的微塑料主要来源于海水养殖和沿岸陆源输入.     

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.     

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.     

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.     

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.     

Removal of heavy metals from sewage sludge by low costing chemical method and recycling in agriculture

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Isolation and preliminary characterization of a 3-chlorobenzoate degrading bacteria

A study was conducted to compare the diversity of 2-, 3-, and 4-chlorobenzoate degraders in two pristine soils and one contaminated sewage sludge. These samples contained strikingly different populations of mono-chlorobenzoate degraders. Although fewer cultures were isolated in the uncontaminated soils than contaminated one, the ability of microbial populations to mineralize chlorobenzoate was widespread. The 3- and 4-chlorobenzoate degraders were more diverse than the 2-chlorobenzoate degraders. One of the strains isolated from the sewage sludge was obtained. Based on its phenotype, chemotaxonomic properties and 16S rRNA gene, the organism S-7 was classified as Rhodococcus erythropolis. The strain can grow at temperature from 4 to 37℃. It can utilize several （halo）aromatic compounds. Moreover, strain S-7 can grow and use 3-chlorobenzoate as sole carbon source in a temperatures range of 10-30℃ with stoichiometric release of chloride ions. The psychrotolerant ability was significant for bioremediation in low temperature regions. Catechol and chlorocatechol 1,2-dioxygenase activities were present in cell free extracts of the strain, but no （chloro）catechol 2,3- dioxygenase activities was detected. Spectral conversion assays with extracts from R. erythropolis S-7 showed accumulation of a compound with a similar UV spectrum as chloro-cis,cis-muconate from 3-chlorobenzoate. On the basis of these results, we proposed that S-7 degraded 3-chlorobenzoate through the modified ortho-cleave pathway.     

Single and joint effects of pesticides and mercury on soil urease

The influence of two pesticides including chlorimuron-ethyl and furadan and mercury （Hg） on urease activity in 4 soils （meadow burozem and phaeozem） was investigated. The soils were exposed to various concentrations of the two pesticides and Hg individually and simultaneously. Results showed that there was a close relationship between urease activity and organic matter content in soil. Chlorimuron-ethyl and furadan could both activate urease in the 4 soils. The maximum increment of urease activity by chlorimuronethyl was up to 14%-18%. There was almost an equal increase （up to 13%-21%） in the urease activity by furadan. On the contrary, Hg markedly inhibited soil urease activity. A logarithmic equation was used to describe the relationship （P〈0.05） between the concentration of Hg and the activity of soil urease in the 4 tested soils. Semi-effect dose （ED50） values by the stress of Hg based on the inhibition of soil urease in the 4 soils were 88, 5.5, 24 and 20 mg/kg, respectively, according to the calculation of the corresponding equations. The interactive effect of chlorimuron-ethyl or furadan with metal Hg on soil urease was mainly synergic at the highest tested concentrations.     

Organochlorine pesticides in soils under different land usage in the Taihu Lake region, China

A field study was conducted in the Taihu Lake region, China in 2004 to reveal the organochlorine pesticide concentrations in soils after the ban of these substances in the year 1983. Thirteen organochlorine pesticides (OCPs) were analyzed in soils from paddy field, tree land and fallow land. Total organochlorine pesticide residues were higher in agricultural soils than in uncultivated fallow land soils. Among all the pesticides, ΣDDX (DDD, DDE and DDT) had the highest concentration for all the soil samples, ranging from 3.10 ng/g to 166.55 ng/g with a mean value of 57.04 ng/g and followed by ΣHCH, ranging from 0.73 ng/g to 60.97 ng/g with a mean value of 24.06 ng/g. Dieldrin, endrin, HCB and α-endosulfan were also found in soils with less than 15 ng/g. Ratios of p,p'-(DDD DDE)/DDT in soils under three land usages were: paddy field ＞ tree land ＞ fallow land, indicating that land usage inlfuenced the degradation of DDT in soils. Ratios of p,p'-(DDD DDE)/DDT ＞1, showing aged residues of DDTs in soils of the Taihu Lake region. The results were discussed with data from a former study that showed very low actual concentrations of HCH and DDT in soils in the Taihu Lake region, but according to the chemical half-lives and their concentrations in soils in 1980s, the concentration of DDT in soils seemed to be underestimated. In any case our data show that the ban on the use of HCH and DDT resulted in a tremendous reduction of these pesticide residues in soils, but there are still high amounts of pesticide residues in soils, which need more remediation processes.     

Alterations of organ histopathology and metallolhionein mRNA expression in silver barb, Puntius gonionotus during subchronic cadmium exposure

Common silver barb,Puntius gonionotus,exposed to the nominal concentration of 0.06 mg/L Cd for 60 d,were assessed for histopathological alterations(gills,liver and kidney),metal accumulation,and metallothionein(MT)mRNA expression.Fish exhibited pathological symptoms such as hypertrophy and hyperplasia of primary and secondary gill lamellae,vacuolization in hepatocytes,and prominent tubular and glomerular damage in the kidney.In addition,kidney accumulated the highest content of cadmium,more than gills and liver.Expression of MT mRNA was increased in both liver and kidney of treated fish.Hepatic MT levels remained high after fish were removed to Cd-free water.In contrast,MT expression in kidney was peaked after 28 d of treatment and drastically dropped when fish were removed to Cd-free water.The high concentrations of Cd in hepatic tissues indicated an accumulation site or permanent damage on this tissue.