多环芳烃类污染物对斑马鱼胁迫效应的研究进展

伴随着现代工业的飞速发展,不同环境介质中污染物的种类、污染范围和污染强度也在不断改变。作为一种强生物损伤性物质,多环芳烃类污染物备受关注。鉴于生态环境中多环芳烃的污染问题日益凸显,对其毒性效应机制研究的概括和总结尤为重要。因此笔者综述了多环芳烃类污染物对斑马鱼不同生物结构层次的毒性效应研究进展,总结并比较了不同多环芳烃类污染物的毒性效应机制和毒性强度。同时就目前斑马鱼在水环境污染评价、水质综合毒性测定方面的应用进行了概述和展望。研究多环芳烃类污染物对斑马鱼的急性毒性作用和富集作用及其分子机制将对开展水环境中突发有机污染的早期预警及水环境安全评估、人体健康评估具有重要意义。     

羟基多氯联苯在小鼠体内的蓄积及迁移特征

羟基多氯联苯(hydroxylated polychlorinated biphenyls, OH-PCBs)作为多氯联苯(polychlorinated biphenyls, PCBs)在生物体内的主要代谢产物之一,能够通过食物链传递在高等动物体内产生蓄积并对其生命健康造成危害。本研究旨在探索OH-PCBs通过水产品摄食途径暴露后,在模式生物体内的蓄积和迁移规律。以鲫鱼为水产品代表,以小鼠为研究对象,向鲫鱼可食性组织添加3-OH-PCB101和4-OH-PCB101的混合标准溶液(1 000 ng·mL^-1)制作加标饲料,并以小鼠每日摄食总量的10%对其进行投喂。分别在暴露实验的第12、24、72和168小时解剖取样,并收集粪便。检测结果显示,2种OH-PCB101在胃、肠等消化组织器官的浓度高于其他组织并能随着粪便排出,且倾向于在含血量较高的组织(如心、肺和脾)中蓄积。OH-PCB101在各组织中的蓄积量由高到低依次为大肠>胃>小肠>脾≈肺>心>肝>肾>血液≈脑>肌肉≈睾丸。同时发现在脑、心、肺、肝、肾、性腺、肌肉等组织样品中,4-OH-PCB101的蓄积浓度始终高于3-OH-PCB101。这表明,虽然通过水产品摄入的OH-PCB101主要通过粪便排出体外,然而在脑、心、肺、肝、胃和脾等11个组织及血液中均产生蓄积,并且2种OH-PCB101可能由于结构不同导致其在各组织中的蓄积量存在差异。本研究有助于揭示OH-PCBs通过摄食暴露后在生物体内的蓄积分布及排泄等归趋问题,同时表明在环境及生物体中蓄积的OH-PCBs等二代持久性污染物对人体健康仍存在潜在威胁。     

Characterization of a sex pheromone in a simultaneous hermaphroditic shrimp, Lysmata wurdemanni

Olfactory chemical cues have been described to play important roles in the control of mate recognition in many decapod crustaceans. However, we still know very little about the chemical characteristics of the cues that coordinate pre-copulative behaviour. In this study, we partially characterized a waterborne sex pheromone of a marine shrimp, Lysmata wurdemanni. Female moulting water was collected and ultrafiltered using 1,000 and 500-Da membranes, respectively, and analysed using HPLC with a Lichrosphere™ RP18 (C18) column. The sex pheromone is likely to be a molecule between 500 and 1,000 Da in size because behavioural bioassays showed that males responded to the supernatant of 500-Da and to the 1,000-Da filtrate, but did not respond to the supernatant of 1,000-Da or to the 500-Da filtrate. There was only one dominant peak (2.86 min) detectable in HPLC chromatograms of the supernatant of the 500-Da filtration. This peak showed a UV absorbance maximum at 274 nm, similar to the recently identified shore crab sex pheromone Uridine-di-phosphate (UDP). Behavioural bioassays confirmed that this peak is a bioactive component of a potential pheromone bouquet, but is different from UDP, which showed no bioactivity in Lysmata wurdemanni. Our results lay the foundation for future studies to purify and eventually identify this sex pheromone.     

The Autothermal Pyrolysis of Waste Tires

Abstract

The growing amount of rubber waste, such as that from tires and cables, has resulted in serious environmental problems. Since rubber waste is not easily biodegradable even after a long period of landfill treatment, material and energy recovery is the preferable alternative to disposal. The potential offered by waste tire pyrolysis for solving both energy and waste treatment problems is widely recognized. Pyrolysis is one method of inducing thermal decomposition without using any oxidizing agent, or using such a limited supply of the agent that oxidization does not proceed to an appreciable extent. The latter may be described as autothermal pyrolysis and will be studied in the present work.

The main objective of this research was to study the operating parameters of autothermal pyrolysis of scrap tires in a laboratory-scale fluidized bed reactor with a 100-cm bed height (10 cm I.D.) and a 100-cm freeboard (25 cm I.D.). Scrap tires were pyrolyzed in a limited oxygen supply, so that the heat for pyrolysis of the scrap tires was provided by combustion of some portion of the scrap tires. The operating parameters evaluated included the effect on the pyrolysis oil products and their relative proportions of (1) the air factor (O.O7–O35); (2) the pyrolysis temperature (370–570 °C); and (3) the catalyst added (zeolite and calcium carbonate). The results show that: (1) the composition of the liquid hydrocarbon obtained is affected significantly by the air factor; (2) the higher operating temperature caused a higher yield of gasoline and diesel; (3) the yield of gasoline increased due to the catalyst zeolite added, and the yield of diesel increased due to the addition of the catalyst calcium carbonate; (4) the principal constituents of gasoline included dipentene and diprene.     

Hexabromocyclododecanes in surface sediments and a sediment core from Rivers and Harbor in the northern Chinese city of Tianjin

In the present study, hexabromocyclododecanes (HBCDs) were investigated in the sediment from Haihe River (HR), Dagu Dainage Canal (DDC) and Tianjin Harbor (TH) at Bohai Bay using a total of 51 samples of surface sediments and a sediment core collected from May to September in 2010, and its diastereomer- and enantiomer-specific profiles were analyzed. The concentration of total HBCDs were generally high, with mean value and ranges of 31.0 and 1.35–634 ng g^?1 dw, respectively. The contamination followed the order of TH > DDC > HR. Higher levels (up to 634 ng g^?1 dw) occurred in the lower reach of HR and DDC located in an industrial area of Tianjin. This is the first time to report so high concentration of HBCDs in sediment in Southeast Asia. The γ-diastereomer dominated in most samples (44 out of 51), and this is in agreement with the diastereomer distribution pattern in industrial products, while α-HBCD was the dominant diastereomer in the other seven samples. However, only few samples exhibited γ-diastereomer ratio similar to that (75–89%) in technical products, indicating the inter-transformation and variable degradation of the different isomers. The high ratio of γ-diastereomer could be used as an indicator for fresh contamination input. Enantiomeric factors (EFs) of HBCD isomers in most of the samples were statistically different from technical products (p < 0.05), showing a trend of more easily enrichment of the (?)-HBCD-enantiomer compared to the (+)-HBCD-enantiomer. The δ- and ε-diastereomers were frequently detected but at low level. The HBCDs in the sediment core showed several peaks, and the greatest value occurred in 2005, when a plastic manufacture plant using HBCD was set up nearby.     

Effect of copper(II) on biodegradation of benzo[a]pyrene by Stenotrophomonas maltophilia

Benzo[a]pyrene (BaP) biodegradation by Stenotrophomonas maltophilia was studied under the influence of co-existed Cu(II) ions. About 45% degradation was achieved within 3 d when dealing with 1 mg L^?1 BaP under initial natural pH at 30 °C; degradation reached 48% in 2 d at 35 °C. Efficacy of BaP biodegradation reached the highest point at pH 4. In the presence of 10 mg L^?1 Cu(II) ions, the BaP removal ratio was 45% on 7th day, and maintained stable from 7 to 14 d at 30 °C under natural pH. The favorable temperature and pH for BaP removal was 25 °C and 6.0 respectively, when Cu(II) ions coexisted in the solutions. Experiments on cometabolism indicated that S. maltophilia performed best when sucrose was used as an additional carbon source. GC–MS analysis revealed that the five rings of BaP opened, producing compounds with one or two rings which were more bioavailable.     

Fate of caffeine in mesocosms wetland planted with Scirpus validus

Uptake, accumulation and translocation of caffeine by Scirpus validus grown in hydroponic condition were investigated. The plants were cultivated in Hoagland’s nutrient solution spiked with caffeine at concentrations of 0.5–2.0 mg L^?1. The effect of photodegradation on caffeine elimination was determined in dark controls and proved to be negligible. Removal of caffeine in mesocosms without plants showed however that biodegradation could account for about 15–19% of the caffeine lost from solutions after 3 and 7 d. Plant uptake played a significant role in caffeine elimination. Caffeine was detected in both roots and shoots of S. validus. Root concentrations of caffeine were 0.1–6.1 μg g^?1, while the concentrations for shoots were 6.4–13.7 μg g^?1. A significant (p < 0.05) positive correlation between the concentration in the root and the initial concentrations in the nutrient solution was observed. The bioaccumulation factors (BAFs) of caffeine for roots ranged from 0.2 to 3.1, while BAFs for shoots ranged from 3.2 to 16.9. Translocation from roots to shoots was the major pathway of shoot accumulation. The fraction of caffeine in the roots as a percentage of the total caffeine mass in solution was limited to 0.2–4.4% throughout the whole experiment, while shoot uptake percentage ranged from 12% to 25% for caffeine at the initial concentration of 2.0 mg L^?1 to 50–62% for caffeine at the initial concentration of 0.5 mg L^?1. However, a marked decrease in the concentration of caffeine in the shoots between d-14 and d-21 suggests that caffeine may have been catabolized in the plant tissues subsequent to plant uptake and translocation.     

In vitro biotransformation of PBDEs by root crude enzyme extracts: Potential role of nitrate reductase (NaR) and glutathione S-transferase (GST) in their debromination

In order to investigate the enzyme transformation of PBDEs and to track the key enzymes involved in PBDE degradation in plants, in vivo exposure of plants of ryegrass, pumpkin and maize and in vitro exposure of their root crude enzyme extracts to PBDEs were conducted. Degradation of PBDEs in the root crude enzyme solutions fit well with the first order kinetics (R² = 0.52–0.97, P < 0.05), and higher PBDEs degraded faster than the lower ones. PBDEs could be transformed to lower brominated PBDEs and hydroxylated-PBDEs by the root crude enzyme extracts with debromination as the main pathway which contributed over 90% of PBDE depletion. In vitro and in vivo exposure to PBDEs produced similar responses in root enzyme activities of which the nitroreductase (NaR) and glutathione-transferase (GST) activities decreased significantly, while the peroxidase, catalase and cytochrome P-450 activities had no significant changes. Furthermore, higher enzyme concentrations of NaR and GST led to higher PBDE debromination rates, and the time-dependent activities of NaR and GST in the root crude enzyme extracts were similar to the trends of PBDE depletion. All these results suggest that NaR and GST were the key enzymes responsible for PBDE degradation. This conclusion was further confirmed by the in vitro debromination of PBDEs with the commercial pure NaR and GST.     

Effective sorption of perfluorooctane sulfonate (PFOS) on hexadecyltrimethylammonium bromide immobilized mesoporous SiO2 hollow sphere

The hexadecyltrimethylammonium bromide (HDTMAB) immobilized hollow mesoporous silica spheres were prepared for the efficient removal of perfluorooctane sulfonate (PFOS) from aqueous solution. Besides the traditional sorption behavior including sorption kinetics as well as effect of solution pH and temperature, the effect of increasing volume which simulated the natural river where the rate of solute and solvent was relatively constant and solution volume was always changing was investigated. The result indicated that the residual PFOS concentrations in aqueous phase decreased with increasing solution pH and ionic strength, whereas they increased with increasing temperature. The HDTMAB immobilized material still maintained high efficiency after increasing volume, that is, the removal kept more than 99% after the treatment when the initial PFOS concentration was 1 mg L^?1. The uptake behavior and morphology of spheres which was characterized by transmission electron microscopy (TEM) revealed that the additional HDTMAB and mesoporous shell were responsible for the enhanced sorption of PFOS. It was concluded that electrostatic interaction and Ca-bridge role played an important role in the sorption of PFOS on the mesoporous SiO₂ hollow spheres, whereas, hydrophobic interaction contributed to the nice sorption performance of PFOS on the HDTMAB immobilized sorbent.     

矿化垃圾混配种植介质的盆栽实验研究

矿化垃圾营养成分和有机质含量较高,但含有重金属和盐分.为了解矿化垃圾的施加比例对植物的生长影响以及植物对矿化垃圾混配种植介质中营养成分的吸收和重金属的富集,将矿化垃圾和本地绿化土按照不同比例混配,研究混配种植介质的理化性质的改善条件、矿化垃圾对植物体内的生物量和叶绿素含量的影响、植物对混配种植介质中营养成分的吸收量以及植物体内各种重金属累积浓度,探索矿化垃圾的最佳施用比例.实验结果表明,矿化垃圾可改善上海本地土壤贫瘠的普遍状况,其添加质量分数在50%～75%合适,对植物生长有利.