太滆南运河入湖污染物控制对策研究

太滆南运河是太湖15条入湖河流之一,水环境质量日益恶化,呈现出明显的氮磷污染特征,成为影响该区域可持续发展的主要问题之一,基于太滆南运河小流域和水质污染分段的特征,计算了研究区域的水环境容量和污染物削减量。以区域内分段入河河流环境容量为前置约束条件,以构建保障太湖入湖水环境安全的三道生态屏障为重点,以控源截污为主要手段,开展太滆南运河水环境生态系统修复,提高入湖河流的生态承载能力,确保入湖水质达标。     

太湖流域漕桥河污染物来源特征

基于对太湖流域漕桥河小流域主要污染物来源构成和污染特征的分析,对污染物入河量进行了计算和修正. 结果表明:漕桥河的COD_Cr入河总量为1 639.9 t/a,主要来源于工业污染和城镇生活污染;氨氮入河总量为174.6 t/a,主要来源于农业面源和工业污染;总氮和总磷入河总量分别为491.0和34.7 t/a,主要来源于农业面源和城镇生活污染. 同时,针对河网地区水系错综复杂的特性,将客水污染纳入污染源范畴,核定客水量,为有效改善河流水环境质量提供了依据.      

太湖上游水环境对植物分布格局的影响机制

对北太湖上游流域的苏南第二大湖泊滆湖及其入太湖的主要河流(太滆运河与漕桥河)的水质和水生植被开展调查、评价与环境生态学研究。调查结果表明所有样点水质均超富营养化,尤以太滆运河与漕桥河的水体污染为甚。通过PCA综合评价,河流绝大多数河段已是Ⅳ类水体,滆湖也已呈Ⅲ类水体。对水生植物类群调查而言,调查发现太隔运河和漕桥河中上游河段水生植物多样性指数均很小,凤眼莲、芦苇和菰为优势种,沉水植被分布很少,群落退化严重,耐污种篦齿眼子菜和水盾草占优势;在湖泊中心区,沉水植物已完全退化。聚类分析发现所调查的植物可分为3大类群。PCO和CCA分别表明河流与湖泊所在的样点间的水体理化性状出现很明显的分离;该流域水体中不同形态N、P含量或底泥N、P含量主要影响水生植物种类组成和分布。     

从水质变化趋势看常州市武南区域重点河流治理成效

为探究武南区域重点河流水质的变化规律、驱动因素以及河流治理成效,基于2006~2018年连续水质监测数据,综合分析了4条重点河流（太滆运河、武宜运河、武进港和永安河）水质演变趋势,并对污染较重的永安河各项水质指标进行了季节性分析和相关性分析.结果表明：2006~2018年,4条河流水质整体呈好转趋势,修正内梅罗指数分别下降36.2%,31.5%,56.4%,48.7%,受河流清淤工程影响,永安河2017年水质有所下降;4条河流氨氮浓度、总氮浓度与高锰酸盐指数下降趋势明显（P<0.05）,总磷浓度则存在一定波动;永安河的总氮、氨氮和高锰酸盐指数间或存在同源关系,氨氮和总氮季节性变化明显,雨季浓度低于旱季,总磷和高锰酸盐指数没有明显季节性变化趋势;城镇化发展与产业结构由传统工业、农业向第三产业的转变均对区域水环境改善有积极作用.     

通吕运河控制断面水质达标分析

文章通过通吕运河规划区域内南通主城区、通州区、海门市、启东市污染物现状入河量和预测量的计算,将通吕运河全线划分为四个水质控制断面,并采用河流一维稳态水质模型对通吕运河沿程水质变化情况进行数值模拟,进行通吕运河四个控制断面水质达标分析,得出选定的四个控制断面水质在不同的污染物入河量时达到地表水环境功能区水质目标需要削减的化学需氧量、氨氮、总磷的排放量,为通吕运河的水环境综合整治提供技术支撑。     

武宜运河小流域平原河网地区氮磷污染来源解析

采用源解析法对工业污染源、生活污染源、农业面源(含种植业、养殖业)进行分析,并统计分析了武宜运河全线水质现状。结果表明,农业面源是武宜运河流域总氮、总磷污染的主要来源,且以养殖业为主,生活污染源是太湖流域氨氮污染的主要来源,且以农村生活污水为主;武宜运河水质以氮磷污染为主,总氮污染最为严重。武宜运河核心区研究范围占总研究范围的比例为35%,总氮、氨氮和总磷入河量分别占研究范围内各类污染物总入河量的42.8%,45.0%,34.1%,污染分布重点区域为武进前黄镇、牛塘镇及宜兴和桥镇所辖行政村。研究范围内农业面源污染分布重点区域为武进前黄镇、牛塘镇、宜兴屺亭街道及和桥镇;生活污染源氮磷污染物排放主要来自高新区及牛塘镇的农村生活污水排放,其次是屺亭街道和前黄镇的农村生活污水。     

流域污染负荷解析与环境容量研究——以安徽太平湖流域为例

以安徽省太平湖流域为例,运用监测、统计数据以及排污系数法对流域内8种污染源的污染排放情况进行全面解析,结合一维水质模型、沃伦威得尔模型以及狄龙模型等水质模型的应用,在流域水质监测的基础上核算了太平湖及主要入湖河流的水环境容量.结果表明,2011年,太平湖流域污染物入湖量为:COD 3863.75t/a,NH3-N 410.24t/a,TP 51.63t/a;城镇和农村生活污染为太平湖流域的主要污染源,约占流域入湖污染物总量的60%;麻川河和浦溪河流域的污染最严重;流域污染物的排放在空间上呈现较为明显的区域分布,经济发达区域污染相对较严重.在当前水质目标下,太平湖仍有相当大的可用容量;浦溪河、秧溪河和舒溪河流域的氨氮和总磷排放量接近环境容量,需进行总量控制及削减.     

流域污染负荷解析与环境容量研究

以安徽省太平湖流域为例,运用监测、统计数据以及排污系数法对流域内8种污染源的污染排放情况进行全面解析,结合一维水质模型、沃伦威得尔模型以及狄龙模型等水质模型的应用,在流域水质监测的基础上核算了太平湖及主要入湖河流的水环境容量.结果表明, 2011年,太平湖流域污染物入湖量为:COD 3863.75t/a, NH3-N 410.24t/a, TP 51.63t/a;城镇和农村生活污染为太平湖流域的主要污染源,约占流域入湖污染物总量的60%;麻川河和浦溪河流域的污染最严重;流域污染物的排放在空间上呈现较为明显的区域分布,经济发达区域污染相对较严重.在当前水质目标下,太平湖仍有相当大的可用容量;浦溪河、秧溪河和舒溪河流域的氨氮和总磷排放量接近环境容量,需进行总量控制及削减.     

流域水质与点源污染关系的监测研究

点源污染物排放与流域水质目标的关系是当前环境管理亟待解决的技术关键问题之一。笔者通过点源排放口—入河排污口—目标河流断面三位一体监测系统运行机制探讨,利用点源排放口与入河排污口同步监测结果分析入河系数,利用入河排污口与目标河流断面同步监测分析影响系数,从而能够得到每个点源污染物排放对相应目标河流控制断面水质的贡献系数,这是确保水质达标而对点污染源进行动态管理的重要技术支持。      

山西省沁河流域农村生活污水入河水质研究

针对农村生活污水管理的需求,在水生态功能区和水环境控制单元的基础上提出了农村生活污水入河水质核算方法.具体步骤包括:①根据地貌类型、降水蒸发量、植被和土壤类型等指标,进行水生态功能区划分;②在水生态功能分区基础上,结合水文单元和行政区边界,划定水环境控制单元;③对控制单元内的水环境容量进行计算,并调查核算各类污染源污染物排放入河量,然后基于水环境容量和污染物入河量确定农村生活污水污染物排放限值.结果表明,沁河流域可划分为2个一级水生态功能区和7个二级水生态功能区,并划分为15个水环境控制单元.以控制单元内沁河上游水质改善区为例,区域内农村生活污水COD排放限值为134.05 mg·L~(-1),且此标准下河流不满足接纳农村污水进行NH_3-N消减的条件.在以上研究成果基础上,提出了农村生活污水分区分级管理措施建议.     

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.     

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.     

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.     

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.