Physiological and molecular responses of the earthworm <Emphasis Type="Italic">Eisenia fetida</Emphasis> to polychlorinated biphenyl contamination in soil

Polychlorinated biphenyls (PCBs) are a class of man-made organic compounds ubiquitously present in the biosphere. In this study, we evaluated the toxic effects of different concentrations of PCBs in two natural soils (i.e. red soil and fluvo-aquic soil) on the earthworm Eisenia fetida. The parameters investigated included anti-oxidative response, genotoxic potential, weight variation and biochemical responses of the earthworm exposed to two different types of soils spiked with PCBs after 7 or 14 days of exposure. Earthworms had significantly lower weights in both soils after PCB exposure. PCBs significantly increased catalase (CAT), superoxide dismutase (SOD), and guaiacol peroxidase (POD) activity in earthworms exposed to either soil type for 7 or 14 days and decreased the malondialdehyde (MDA) content in earthworms exposed to red soil for 14 days. Of the enzymes examined, SOD activity was the most sensitive to PCB stress. In addition, PCB exposure triggered dose-dependent coelomocyte DNA damage, even at the lowest concentration tested. This response was relatively stable between different soils. Three-way analysis of variance (ANOVA) showed that the weight variation, anti-oxidant enzyme activities, and MDA contents were significantly correlated with exposure concentration or exposure duration (P < 0.01). Furthermore, weight variation, CAT activity, and SOD activity were significantly affected by soil type (P < 0.01). Therefore, the soil type and exposure time influence the toxic effects of PCBs, and these factors should be considered when selecting responsive biomarkers.     

废水营养比对固定化藻菌去除污染物的影响及动力学研究

海藻酸钙作载体的固定化藻菌小球,经壳聚糖覆膜后,用于模拟废水的处理。通过研究废水初始氨氮浓度及碳氮比对固定化藻菌小球处理效果的影响,发现初始氨氮浓度为50 mg/L时,氨氮的去除率达最高值74.4%;碳氮比为35∶1时,COD去除率达最高值77.7%。系统最佳氮磷比与碳氮比分别为5∶1和35∶1。固定化藻菌降解有机物的动力学过程为一级不可逆生化反应过程,其降解速率常数约为0.099 h-1。     

Effect of temperature on blood parameters of the salamander <Emphasis Type="Italic">Batrachupems tibetanus</Emphasis> (Schmidt, 1925) (Amphibia: Hynobiidae)

To better understand how Batrachupems tibetanus responds to different temperature regimes in the blood parameters and to estimate the change in plasma cortisol level in this species exposed to different temperatures, the animals were stochastically divided into three groups and exposed respectively to 4.6°C, 14.6°C and 19.6°C for 12 days. The concentrations of glucose, total protein, albumin, triacylglycerol, Ca²⁺, K⁺, Na⁺, Cl⁻, and plasma cortisol level were measured respectively. There was no significant difference between the plasma cortisol level of the control group and the experiment groups. Glucose level at 4.6°C and 19.6°C was significantly lower than glucose level at 14.6°C. The plasma triacylglycerol level was significantly influenced by acclimation temperature. The concentration of total protein, albumin, globulin and the ratio between albumin and globulin were not significantly influenced by temperature when compared with control group. There was no significant change in concentration of Ca²⁺ at different temperatures. The concentration of K⁺ was significantly influenced by temperature. Plasma K⁺ level significantly increased at 19.6°C. The plasma Na⁺ level and Cl⁻ were significantly influenced by temperature. Na⁺: Cl⁻ ratio was significantly influenced by temperature. Therefore, glucose, triacylglycerol, Na⁺ and Cl⁻ levels could be considered as indicators of thermal stress in B. tibetanus; plasma cortisol, albumin, globulin levels, and albumin/globulin ratio are not influenced by temperature.     

Accumulation and fraction distribution of Ni(II) in activated sludge treating Ni-laden wastewater

The accumulation and fraction distribution of Ni(II) in sludge was determined, and their effect on the performance of sequencing batch reactor (SBR) systems was evaluated at laboratory scale. The results showed that the removal efficiencies of substrates decreased significantly with increasing feeding concentration of Ni(II) into SBRs. The concentration of Ni(II) fed into the SBRs was significantly positively correlated with the Ni(II) contents accumulated in the sludge, while it was negatively correlated with the biomass in the SBRs. The accumulated Ni(II) in the sludge was distributed mainly in the available fraction, accounting for 75.8–90.0 % of the total Ni(II) content. The accumulated content of Ni(II) in each sludge fraction could be predicted satisfactorily by the feeding Ni(II) concentrations in the solutions. As compared with the total contents and other chemical fractions, Ni(II) in the oxidizable fraction in sludge exhibited more important inhibition effects on sludge microorganisms in the SBRs.     

Development of natural treatment system consisting of black soil and Kentucky bluegrass for the post-treatment of anaerobically digested strong wastewater

To develop a sound post-treatment process for anaerobically-digested strong wastewater,a novel natural treatment system comprising two units is put forward.The first unit,a trickling filter,provides for further reduction of biochemical oxygen demand and adjustable nitrification.The subsequent soil–plant unit aims at removing and recovering the nutrients nitrogen(N),phosphorus(P)and potassium(K).As a lab-scale feasibility study,a soil column test was conducted,in which black soil and valuable Kentucky bluegrass were integrated to treat artificial nutrient-enriched wastewater.After a long-term operation,the nitrification function was well established in the top layers,despite the need for an improved denitrification process prior to discharge.P and K were retained by the soil through distinct mechanisms.Since they either partially or totally remained in plant-available forms in the soil,indirect nutrient reuse could be achieved.As for Kentucky bluegrass,it displayed better growth status when receiving wastewater,with direct recovery of 8%,6% and 14% of input N,P and K,respectively.Furthermore,the indispensable role of Kentucky bluegrass for better treatment performance was proved,as it enhanced the cell-specific nitrification potential of the soil nitrifying microorganisms inhabiting the rhizosphere.After further upgrade,the proposed system is expected to become a new solution for strong wastewater pollution.     

事故致因理论的研究与应用简评

阐明事故致因理论的重要性和应用情况对于促进其发展、应用及提高事故预防效果十分重要。通过分析国内外的重要观点得知,安全科学是事故预防的科学,事故致因理论是发现事故原因、有效预防事故的工具,当然具有特别的重要性;但事故致因理论研究在我国开展较晚,所以目前的研究与应用并不充分。综合以往文献,给出了事故致因理论的实质性科学含义是事故的原因定义、原因间、原因与事故间的逻辑关系,它们可形象地综合表达为事故致因模型,其获取过程中不可或缺的方法是对以往事故案例的原因分析;通过观察安全管理实务认识到,社会组织要有效管理其安全健康和环保业务,选择一种事故致因模型作为总体思路且连续运转,十分必要。     

窄前沿高压脉冲放电等离子体降解水中苯胺

采用高压电极在气相、接地极在液相的针-板式放电装置,考察了窄前沿高压脉冲放电等离子体降解水中苯胺的效果。比较了窄前沿高压脉冲放电(上升沿为25μs)和常规高压脉冲放电(上升沿为5μs)的脉冲波形、单脉冲能量、脉冲功率、对苯胺的降解效果、能量利用率以及发射光谱的差异。实验结果表明,窄前沿高压脉冲和常规高压脉冲放电的单脉冲能量分别为0.0078 J和0.016 J,脉冲功率分别为1.02 W和1.285 W,放电60 min后对苯胺的降解率分别为90%和55%,前者的能量利用率是后者的2.06倍。利用多通道光纤光谱仪在气相放电中检测到5种活性物质,分别是O、O+、N2、N和·OH,且窄前沿脉冲产生活性物质的信号强度高于常规脉冲。     

土壤生态系统微生物多样性技术研究进展

土壤微生物多样性主要研究土壤环境中微生物种群的类别、丰度、分布、结构变化及微生物群落功能的多样性,是土壤生物多样性研究的主体部分。19世纪末,传统的微生物分离培养方法应用于土壤微生物多样性解析。至20世纪70年代,建立了以磷脂脂肪酸图谱分析法(PLFA)和BIOLOG微量分析法为代表的对土壤微生物群落多样性评价的生物化学方法。20世纪90年代后期,随着分子生物学技术的快速发展,建立了变性梯度凝胶电泳(DGGE)、末端限制性片段长度多样性(TRFLP)、克隆文库和高通量测序等土壤微生物多样性研究方法。本文综述了土壤微生物多样性研究技术的原理、进展,并对不同技术的优缺点及应用进行探讨,并对相关领域研究提出思考。     

垃圾焚烧残渣填埋场渗滤液回喷处理试验研究

研究了回喷负荷、回喷次数对焚烧残渣填埋场渗滤液回喷处理的影响。正交试验结果表明,回喷负荷为24.6 L/(m2·d)、回喷次数为6次/d时,蒸发比为0.94,影响蒸发比的关键因素是回喷负荷,其次为回喷次数,二者的交互作用对蒸发比影响不显著。