4,4'-二氨基二苯基甲烷对浮萍(Lemna minor L.)毒性作用

以浮萍(Lemna minor L.)为受试生物,通过研究不同浓度(0、0.6、1.8、5.4、16.2和48.6 mg·L-1)的4,4'-二氨基二苯基甲烷(4,4'-methylenedianiline,MDA)对浮萍生长、叶绿素含量、PSⅡ最大光化学效应(Fv/Fm)、质膜透性及超氧化物歧化酶(SOD)、过氧化物...     

Toxicological evaluation of bacterial decolourised anaerobically treated distillery effluent with common duckweed (Lemna minor)

Duckweed (Lemna minor) a small vascular plant, grows rapidly, is sensitive to a wide variety of toxicants and is easy to culture. A method is described that measures duckweed frond growth, chlorophyll, protein and biomass content as indicator of growth inhibition. The physico-chemical analysis of anaerobically treated distillery effluent revealed high BOD (28,000 mg/l), COD (52,400 mg/l) and dark brown colour (180,000 Co. Pt.). This effluent showed high toxicity to Lemna minor after 96 h of exposure in laboratory condition. EC50 of the fronds for chlorophyll, protein and biomass was found to be 25%, however, the bacterial decolourised effluent showed reduction of BOD (87.50%), COD (84.50%) and colour (76%). Further the toxicity evaluation with Lemna minor showed toxicity reduction up to 63% for all tested parameters. The EC50 noted for chlorophyll, protein and biomass was 100% concentration of decolourised effluent.     

Physicochemical properties of non-living water hyacinth (Eichhornia crassipes) and lesser duckweed (Lemna minor) and their influence on the As(V) adsorption processes

Eichhornia crassipes (Ec) and Lemna minor (Lm) are aquatic plants. They are considered as weeds of the water and approach being a scourge in many parts of the world, choking waterways and hindering transport upon them. At the same time they are known to readily remove heavy metal ions from water. This paper considers the use of non-living plants as novel and inexpensive biosorbent for the removal of As(V) from watersheds. In the first place they were conditioned and characterised to determine their physicochemical and surface properties and in the second place their adsorption properties for As(V) from aqueous solution were evaluated considering the toxicity of this metalloid in the environment. It describes the methodology to prepare the non-living biomasses; the physicochemical characterisation by SEM, XRD, FTIR, TGA analyses and surface characterisation of Ec and Lm by specific surface, hydration kinetic, point of zero charge determination by mass titration, active site density and XPS analysis are described. Both studied biomasses were found to be potential bio-sorbents for arsenic ions from aqueous solution. According to their efficiency to remove arsenic, they can be used in a very low cost metalloid ions removal system.     

Effect of selenium on the growth of Lemna minor

The effect of selenium on the vegetative reproduction of cultured Lemna minor was investigated. Cultures were grown for 28 days at a temperature of 23 ± 3°C and under a constant (24 h) light cycle. Growth was monitored every seven days. The growth of L. minor was inhibited at high concentrations (>5mg/L [Se]), but stimulated at low concentrations (0.2—2mg/L [Se]). This stimulation of growth at low selenium concentrations has significant implications for the use of selenium enriched superphosphate fertilisers on selenium deficient pastures.     

青萍生长抑制试验对稀脉浮萍的适用性研究

为了验证我国本土常见的稀脉浮萍(Lemna aequinoctialis)是否适用于以青萍(Lemna minor)作为标准试验生物的生长抑制试验,对两种浮萍的毒性效应终点和毒性响应差异进行比较。通过对两种浮萍的总叶面积、干重、鲜重同叶状体数之间的相关性进行分析,根据《OECD化学品测试准则No.221浮萍生长抑制试验》,遵从良好实验室规范(GLP),将两种浮萍暴露于参比物质3,5-二氯苯酚,进行7 d更新式毒性试验,暴露浓度为(1.0~10)mg·L-1。结果表明,青萍的培养条件、试验方法以及毒性效应终点均适用于稀脉浮萍,两种浮萍的毒性试验呈现出相似的时间-效应关系和剂量-效应关系,两者的毒性效应浓度具有可比性,且数值上接近。以上实验结果可以得出,稀脉浮萍适用于生长抑制试验;鉴于稀脉浮萍在我国分布广泛、容易获取,稀脉浮萍可作为毒性测试的国家标准试验生物。     

三苯基锡对青萍生长及酶活性的影响

以青萍(Lemna mino)为实验生物,通过研究不同浓度(0、0.04、0.08、0.12、0.16、0.20mg·L-1)的三苯基锡(TPT)对青萍生长发育及过氧化氢酶(CAT)和过氧化物酶(POD)活性的影响,初步探讨了TPT对水生浮萍植物的毒性作用,以期为及时发现并排除TPT污染提供理论和直观依据.实验结果表明:培养4d后,TPT对青萍叶片生长量的半数抑制浓度(IC50)为0.10mg·L-1;CAT、POD活性随TPT处理浓度的升高显著升高(各暴露组与对照组均差异显著,p<0.05).结果显示,TPT对青萍具有明显的毒性作用,CAT和POD活性的变化可作为反映TPT污染胁迫的敏感指标.     

Performance of bioferric-submerged membrane bioreactor for dyeing wastewater treatment

Adding iron salt or iron hydroxide to sludgemixed liquor in an aeration tank of a conventional activated sludge processes (bioferric process) can simultaneously improve the sludge’s filterability and enhance the system’s treatment capacity. In view of this, Fe(OH)₃ was added to a submerged membrane bioreactor (SMBR) to enhance the removal efficiency and to mitigate membrane fouling. Bioferric process and SMBR were combined to create a novel process called Bioferric-SMBR. A side-by-side comparison study of Bioferric-SMBR and common SMBR dealing with dyeing wastewater was carried out. Bioferric-SMBR showed potential superiority, which could enhance removal efficiency, reduce membrane fouling and improve sludge characteristic. When volumetric loading rate was 25% higher than that of common SMBR, the removal efficiencies of Bioferric-SMBR on COD, dye, and NH₄ ⁺-N were 1.0%, 9.5%, and 5.2% higher than that of common SMBR, respectively. The trans-membrane pressure of Bioferric-SMBR was only 36% of that in common SMBR while its membrane flux was 25% higher than that of common SMBR. The stable running period in Bioferric-SMBR was 2.5 times of that in common SMBR when there was no surplus sludge discharged. The mixed liquor suspended solids concentration of Bioferric-SMBR was higher than that of common SMBR with more diversified kinds of microorganisms such as protozoans and metazoans. The mean particle diameter and specific oxygen uptake rate of Bioferric-SMBR were 3.10 and 1.23 times the common SMBR, respectively.     

砷污染土壤对不同品种水稻生长的影响

重金属如何影响水稻(Oryza sativa L.)的生长及产量一直是粮食生产中的研究重点。利用盆栽实验,首次比较了砷(As)对三个品系(杂交稻、常规稻和糯稻)共20个品种水稻生长的影响,以期选定适合在As污染区种植的水稻品种。结果显示,不同品系水稻在As污染土壤中的生长显著不同,杂交稻的生长优于糯稻和常规稻,但糯稻和常规稻差异不显著,表明杂交稻更适宜在砷污染土壤种植。同一品系内不同品种水稻的生长也有较大差异,杂交稻II优804的干物质积累量最高,每株达到0.055g。     

The effects of alginate microspheres on phytoremediation and growth of Lemna minor in the presence of Cd

Today, the removal of increased amount of contaminant concentrations in nature such as metals, nanoparticles, has become an essential issue to struggle with. In this paper, both the toxic effects of non-essential Cd on Lemna minor in presence of alginate microspheres and metal removal capacity of Cd-exposed L. minor and microspheres were investigated. Three test groups were constructed: group (L) containing Lemna, group (M) containing alginate microsphere and group (L?+?M) containing alginate microsphere and Lemna. Five different levels of Cd concentrations were added into these groups. Estimation models were constructed to estimate Cd removal capacities of L. minor and microspheres, and time-concentration-dependent growth (GRC) rates of both microsphere-containing and non-containing groups were modelled by regression analysis. It was seen that microspheres alone only had no positive or negative effects on Lemna growth. It was observed that, for all test groups the time-dependent growth rate has both increase–decrease trends in general. The toxicity effect of Cd on Lemna growth was reduced by adding microspheres into medium. Furthermore, the results stated that test groups containing only microspheres (M, 0–97.56%) and consortium groups (M?+?L, 0–98.26%) were slightly more successful in Cd removal process compared to Lemna (L) groups (L, 0–97.32%).     

镧、锌及其交互作用对浮萍活性氧清除系统的影响

以浮萍(Lemnaminor)为材料,研究La、Zn及其交互作用对体内活性氧清除系统的影响,单独施加20mg·L-1的La或Zn对浮萍都有明显的伤害作用,且Zn的毒性远大于La。La、Zn复合处理不同程度地减弱各自的毒性,表现为植株叶绿素含量、蛋白质含量及过氧化氢酶(CAT)活性下降减缓;谷胱甘肽(GSH)、抗坏血酸(AsA)含量提高;超氧化物歧化酶(SOD)活性增强;过氧化物酶(POD)活性降低。各处理对浮萍的毒性由大到小的顺序依次为:Zn、La、Zn+La。     

Bioremediation of heavy metal contaminated medium using Lemna minor,Daphnia magna and their consortium

Single, dual and triple mixtures of totally seven different mixture combinations of the metals Al, Ba and Fe were examined in Lemna minor (L) culture, Daphnia magna (D) culture and in a consortium culture consisting of L. minor and D. magna. In this study: (a) differences in removed metal proportions at the end of 24 and 48?h, (b) differences in removed metal amounts due to cultures, (c) differences in the removed proportions of a metal in distinct mediums and (d) removal correlation of the metals due to cultures were investigated. The study results showed that among the metals Al, Ba and Fe, Al has the most toxic effect on organisms involved in this study. Although similar toxicity results of Al and Fe on test groups were observed, Ba gave different toxicity results on test groups. An overview of the bioremediation results indicates that L. minor removes the metals Al and Fe more successfully than Ba. Different mixture combinations of metals performed dissimilar removal results in the same cultures. According to the correlations analysis for the metals Ba and Fe, a high correlation was recorded between the consortium group and test groups containing only D. magna, r?=?0.88, r?=?0.91, respectively.     

Occurrence and migration of microplastics and plasticizers in different wastewater and sludge treatment units in municipal wastewater treatment plant

● Reduce the quantifying MPs time by using Nile red staining. ● The removal rate of MPs and PAEs in wastewater and sludge were investigated. ● MPs and PAEs were firstly analyzed during thermal hydrolysis treatment. ● The removal of PAEs from wastewater and sludge was mainly biodegradation. Microplastics (MPs) and plasticizers, such as phthalate esters (PAEs), were frequently detected in municipal wastewater treatment plants (MWTP). Previous research mainly studied the removal of MPs and PAEs in wastewater. However, the occurrence of MPs and PAEs in the sludge was generally ignored. To comprehensively investigate the occurrence and the migration behaviors of MPs and PAEs in MWTP, a series of representative parameters including the number, size, color, shape of MPs, and the concentrations of PAEs in wastewater and sludge were systematically investigated. In this study, the concentrations of MPs in the influent and effluent were 15.46±0.37 and 0.30±0.14 particles/L. The MP removal efficiency of 98.1% was achieved and about 73.8% of MPs were accumulated in the sludge in the MWTP. The numbers of MPs in the sludge before and after digestion were 4.40±0.14 and 0.31±0.01 particles/g (dry sludge), respectively. Fourier Transform Infrared Spectroscopy (ATR FT-IR) analysis showed that the main types of MPs were polyethylene terephthalate (PET), polypropylene (PP), polyethylene (PE), and polystyrene (PS). Six PAEs, including phthalate (DMP), diethyl phthalate (DEP), diisobutyl phthalate (DIBP), ortho dibutyl phthalate (DBP), butyl benzyl phthalate (BBP), and bis(2-ethyl) hexyl phthalate (DEHP), were detected in the MWTP. The concentrations of total PAEs (ΣPAEs) in the influent and effluent were 76.66 and 6.28 µg/L, respectively. The concentrations of ΣPAEs in the sludge before and after digestion were 152.64 and 31.70 µg/g, respectively. In the process of thermal hydrolysis, the number and size of MPs decreased accompanied by the increase of the plasticizer concentration.     

Antioxidative response of Lemna polyrrhiza L. to cadmium stress

Growth, lipid peroxidation, different antioxidative enzymes and metal accumulation were studied in Lemna polyrrhiza treated with different concentrations (1-40 ppm) of CdSO4. The growth of the plant was slightly enhanced with 1 ppm, while higher concentrations retarted growth and multiplication of fronds, the effect being concentration and dose dependant. Increase in malondialdehyde content was insignificant after the first week but a prolonged exposure led to significant (p < 0.05) increase of about 38% and 45% over the control in 20 and 30 ppm, respectively after four weeks. Catalase (EC 1.11.1.6; CAT) activity increased at low concentration, but it declined to 42% and 54% at 40 ppm after 6 and 30 days, respectively Superoxide dismutase (EC 1.15.1.1; SOD), ascorbate peroxidase (EC 1.11.1.11;APx) and glutathione reductase (EC 1.6.4.2) increased at both low as well at high concentrations, but a prolonged exposure to high concentration of Cd (40 ppm) led to significant (p < 0.05) decline in the mean activities of these antioxidant enzymes. Accumulation of Cd in biomass was concentration and time dependant However at high concentration of 40 ppm, Cd accumulation did not increase significantly (p < 0.05) with time. Increased activities of antioxidant enzymes in Cd treated plants suggest that metal tolerance in L. polyrrhiza might be associated to the changes of antioxidant enzymatic activities.     

镉污染对水稻不同生育期生长和品质的影响

通过盆栽试验,研究了在CK、5、10和20 mg·kg-1 4个不同镉处理浓度下,水稻生长发育农艺指标和部分品质指标的变化,同时分析了不同生育期水稻根系活力和伤流液中镉含量的变化规律.结果表明,淹水条件下,镉对水稻产生生育障碍的浓度比较高.土镉20.84 mg-kg-1时,水稻的经济产量减产超过10%,同时,糙米中直链淀粉的含量也显著增加.当土壤镉含量为4.48 mg·kg-1时,糙米中镉含量显著增加而蛋白质含量显著减少.在水稻不同的生长发育期,根系活力与伤流液中镉的含量表现出相同的变化趋势.伤流液中镉在营养生长阶段吸收最大,且与土壤中的镉呈线性关系.     

制革废水处理系统各级出水的生态毒性评价

采用生态毒理学常用的大型溞（Daphnia magna）和活性污泥（activated sludge）作为试验系统,对制革废水处理系统各个环节出水进行毒性试验,以评价其处理效果。按照OECD标准试验方法,选取本实验室繁殖的大型溞（溞龄小于24 h）,和采自以处理生活污水为主的污水处理厂活性污泥,分别使用重铬酸钾和3,5-二氯酚作为参比物验证大型溞和活性污泥的毒性敏感性。以大型溞活动抑制和活性污泥呼吸抑制作为毒性终点,利用48 h静态试验和3 h曝气试验分别评价水样对于大型溞活动和活性污泥呼吸作用的急性毒性效应。统计各试验组大型溞的活动情况和活性污泥的呼吸速率,分别将其与空白对照组进行比较,计算大型溞的活动抑制率和活性污泥的呼吸抑制率,采用Bliss法统计制革废水处理系统各个环节出水对大型溞和活性污泥的半数抑制浓度（EC50）。结果表明：制革废水依次经过厌氧脱硫反应器、脱色厌氧反应器、微曝气反应器和厌氧氨氧化反应器的生物处理系统处理,其出水对大型溞和活性污泥的急性毒性已大为降低。进水、厌氧脱硫反应器出水、脱色厌氧反应器出水、微曝气反应器出水和厌氧氨氧化反应器出水对大型溞活动抑制试验的48 h-EC50分别为41.3%、32.2%、48.0%、91.2%和无抑制作用;活性污泥呼吸抑制试验3 h-EC50则分别为178.2%、101.5%、689.7%、184.6%和无抑制作用。总体上毒性呈现逐渐降低的趋势,而且大型溞比活性污泥更为灵敏。大型溞和活性污泥的生态毒性结果与化学分析的结果相互补充,可为制革废水处理提供预警和效果评价提供科学依据。     

Performance and mechanistic study on electrocoagulation process for municipal wastewater treatment based on horizontal bipolar electrodes

• EC modified with BPEs enhances pollutant removal and reduce energy consumption. • Increasing BPE number cannot increase flocculants yield exponentially. • Simulations help to predict the distribution of electrochemical reactions on BPEs. The design of electrodes is crucial to electrocoagulation process (EC), specifically, with respect to pollutant removal and energy consumption. During EC, the mechanisms for interaction between different electrode arrangement and electrode reactions remain unclear. This work presents an integrated EC process based on horizontal bipolar electrodes (BPEs). In the electrochemical cell, the graphite plates are used as driving cathode while either Fe or Al plates serves as driving anode and BPEs. The BPEs are placed horizontally between the driving electrodes. For municipal wastewater treatment, the pollutant removal efficiency and energy consumption in different configurations of two-dimension electrocoagulation (2D-EC) system with horizontal BPEs were investigated. The removal efficiency of turbidity, total phosphorus and total organic carbon increased significantly with the number of BPEs. Noted that the energy consumption for TP removal decreased by 75.2% with Fe driving anode and 81.5% with Al driving anode than those of 2D-EC, respectively. In addition, the physical field simulation suggested the distributions of potential and current in electrolyte and that of induced charge density on BPE surface. This work provides a visual theoretical guidance to predict the distribution of reactions on BPEs for enhanced pollutant removal and energy saving based on electrocoagulation process for municipal wastewater treatment.     

Microbial community structure in different wastewater treatment processes characterized by single-strand conformation polymorphism (SSCP) technique

In order to investigate microbial community structures in different wastewater treatment processes and understand the relationship between the structures and the status of processes, the microbial community diversity, variety and distribution in five wastewater treatment processes were studied by a culture-independent genetic fingerprinting technique single-strand conformation polymorphism (SSCP). The five processes included denitrifying and phosphate-removal system (diminished N), Chinese traditional medicine wastewater treatment system (P), beer wastewater treatment system (W), fermentative biohydrogen-producing system (H), and sulfate-reduction system (S). The results indicated that the microbial community profiles in the wastewater bioreactors with the uniform status were very similar. The diversity of microbial populations was correlated with the complexity of organic contaminants in wastewater. Chinese traditional medicine wastewater contained more complex organic components; hence, the population diversity was higher than that of simple nutrient bioreactors fed with molasses wastewater. Compared with the strain bands in a simulated community, the relative proportion of some functional microbial populations in bioreactors was not dominant. Fermentative biohydrogen producer Ethanoligenens harbinense in the better condition bioreactor had only a 5% band density, and the Desulfovibrio sp. in the sulfate-reducing bioreactor had less than 1.5% band density. The SSCP profiles could identify the difference in microbial community structures in wastewater treatment processes, monitor some of the functional microbes in these processes, and consequently provide useful guidance for improving their efficiency.     

高原粳稻在不同海拔条件下品质特性分析

高原粳稻育种基本上以海拔高度开展育种研究,为了明确海拔变化对稻米品质的影响,选用7个不同的品种(Oriza sativa L.)分别种植在6个不同海拔生态条件下,研究了在不同海拔条件下的稻米品质性状的变化规律.利用方差分析法对品质性状在不同海拔间的变异进行差异显著性分析,并对品质性状在海拔间的变异系数进行聚类和主成分综合分析评价.研究结果表明,海拔梯度变化对胶稠度、蛋白质、垩白率等影响较大;其次是整精米率;糙米率、粒长、精米率对海拔变化较迟钝,受海拔影响较小,主要受遗传因子的制约;直链淀粉含量在海拔间差异不显著,主要来自于品种间的差异,性状表现主要受品种遗传因子的制约,受环境影响小;高原立体气候条件下,品种须注意海拔种植范围.     

(N-[2-(2-氧-1-咪唑烷基)乙基]-N '-苯基脲(EDU)对环境臭氧胁迫下的水稻和小麦生长的影响

通过对作物定期喷施不同浓度(0、150、300和450 mg·L-1)的N-[2-(2-氧-1-咪唑烷基)乙基]-N'-苯基脲(ethy lenediurea,EDU)溶液,研究EDU对环境O3胁迫下水稻“粤晶丝苗2号”(Oryza sativa L.Yuejingsi 2)和小麦“北农9549”(Triticum a...     

Adsorptive removal of rhodamine B from textile wastewater using water chestnut (Trapa natans L.) peel: adsorption dynamics and kinetic studies

Water chestnut peel, an agricultural bio-waste, was used as a biosorbent for removal of rhodamine B (RhB), basic textile dye, from an aqueous solution. The effects of various experimental parameters were studied. The equilibrium data correlated well with a Freundlich isotherm (R² = 0.98–0.99) followed by a Halsey isotherm model (R² = 0.98–0.99) which indicated heterogeneity of the adsorbent surface and multilayer adsorption of RhB dye onto the water chestnut peel waste (WCPW). High correlation coefficients (R² = 0.99) together with close agreement between experimental q_e (0.4–1.7 mg g^?1) and calculated q_e (0.4–2.5 mg g^?1) suggested that the adsorption process followed pseudo-second-order kinetics, with k₂ values in the range of 52–3.4 × 10^?1 g mg^?1 min^?1 at different concentrations. The overall mechanism of adsorption was controlled by both liquid-film and intra-particle diffusions. The negative values of change in Gibb's free energy (?ΔG⁰ = 19.2–29.2 kJ mol^?1) and positive values of change in enthalpy (ΔH⁰ = 30.9–117.6 kJ mol^?1) revealed the process to be spontaneous and endothermic. WCPW was found to be an effective adsorbent for removal of RhB, a cationic dye, from an aqueous solution.