利用蚯蚓处理城市污水厂剩余污泥的初步试验研究

采用城市污水处理厂的剩余污泥（滤泥）和牛粪直接配置养殖蚯蚓的饲料,按照不同比例的配料分组进行了饲养蚯蚓的试验研究。在适宜的环境条件下,经过21 d培养,大平二号蚯蚓的最少增重为54％,最高增重达100％;平均产卵茧的数量为0．687个／条蚯蚓。研究结果表明,滤泥不需经过发酵即可用于养殖蚯蚓,牛粪与滤泥配置的比例为1∶1或0．3：0．7时,有利于蚯蚓的代谢和繁殖,并可确保蚯蚓养殖的安全。     

The effect of temperature on leaching and subsequent decomposition of dissolved carbon from inundated floodplain litter: implications for the generation of hypoxic blackwater in lowland floodplain rivers

Dissolved organic carbon export from floodplain litter during flood events is an important energy subsidy for lowland rivers. Temperature affects both the release and decomposition of dissolved organic carbon from floodplain plant litter. Unseasonally warm flood conditions have resulted in the release and consumption of carbon at a rate so rapid that water column oxygen has been depleted, causing the death of aquatic organisms upon exposure to this ‘hypoxic blackwater’. To date, there has not been a systematic investigation of the role of temperature on hypoxic blackwater dynamics. In a series of laboratory experiments, we investigated the temperature dependence of both leaching and decomposition of carbon from a common floodplain litter component in south-eastern Australia – the leaves of the river red gum Eucalyptus camaldulensis. The leaching rate increased with temperature and approximated Arrhenius kinetics. Additionally, the solubility of the leaf carbon increased substantially at temperatures above ～25°C. The rate of organic carbon respiration also increased with temperature, and the relationship with temperature was approximately linear. These data can be used to improve models for the prediction of hypoxic blackwater risk.     

137Cs示踪红壤丘陵区坡地土壤侵蚀的研究--以江西丰城市为例

通过137Cs示踪技术,并采用相关的土壤侵蚀定量模型,对红壤丘陵区江西丰城市坡面不同土地利用类型、方式以及不同地貌部位的土壤侵蚀进行了研究。结果表明：研究区137Cs的本底值为1 992.45±145.63 Bq/m2;试验区典型坡地不同地貌部位均存在着一定程度的土壤侵蚀,且侵蚀强度总的变化趋势为坡底部>坡中部>坡顶部;不同土地利用类型和方式下的坡面侵蚀强度亦呈现一定的分异现象,从大到小依次为耕作土坡面>退耕30年+退耕1年混合坡面>退耕30年坡面>荒坡。     

TiO2悬浆体系光催化降解酸性红B动力学分析

采用TiO2悬浆体系, 以高硼紫外灯为光源, 考察了酸性红B 光催化降解中溶液初始质量浓度、催化剂投加量、无机盐、空气通入量、pH 值对光催化降解速率影响.用Langmuir-hinshelwood 方程描述酸性红B光催化动力学行为. 结果表明:初始质量浓度增加, 反应由一级向零级过渡; 催化剂投加量在0.5～2.5 g/L时, 30 mg/L酸性红B一级反应速率常数与投加量成线性关系; 5种溶解性无机盐对光催化降解酸性红B存在抑制作用, 阴离子影响大于阳离子; 通入空气影响动力学行为, 改变反应级数.本实验在pH 值为3时光催化降解效果最佳, 且酸性条件下比碱性下条件效果更好;TiO2表面吸附能力随pH 值增大而减弱,光催化过程控制步骤在酸性和碱性条件不同.     

海藻酸钠固定化纳米铁还原脱色活性红X3B

采用海藻酸钠固定纳米铁制备海藻酸钠纳米铁小球,研究了海藻酸钠浓度、纳米铁含量、活性红X3B浓度、反应温度、pH值等对海藻酸钠固定化纳米铁小球还原活性红X3B的影响.采用高效液相色谱（HPLC）、紫外可见分光光度计（UV-Vis）、扫描电镜（SEM）、透射电镜（TEM）等方法分析污染物的还原脱色过程.结果表明,X3B的还原脱色获得了较好的效果,当温度25.0℃,海藻酸钠浓度2.0%,纳米铁含量2.0g/L,转速200r/min,pH值10.9时,反应720min后,25.0mg/L活性红X3B的脱色率达98.9%.海藻酸钠凝胶对活性红X3B没有吸附作用,海藻酸钠固定化纳米铁小球降解活性红X3B的主要机制为纳米零价铁的还原作用.     

Bioaccumulation of cadmium,lead and zinc in liver and kidney of red fox (Vulpes vulpes) from NW Spain: influence of gender and age

Cd, Pb, and Zn were quantified in liver and kidney of red foxes (Vulpes vulpes) which were hunted during the 2003–2011 hunting seasons in Galicia (NW Spain). The effects of age and gender were evaluated to determine whether these variables should be included in future biomonitoring studies. The concentrations of hepatic and renal Cd (average 0.6 and 1.3 µg/g) and Pb (0.8 and 0.06 µg/g, respectively) were similar to background levels, with no known toxicological relevance. Similarly, the average levels of Zn in liver and kidney (77 and 17 µg/g) were in the range of physiological levels for canids. Although no significant gender-dependent variations were observed, the effect of aging was evident: the levels of hepatic Pb and both hepatic and renal Cd were higher in adults than in juveniles. Age should be included as a parameter during future biomonitoring programs focusing on trace metal bioaccumulation in red foxes.     

Equilibrium,kinetic, and quantum chemical studies on the adsorption of Congo red using Imperata cylindrica leaf powder activated carbon

Leaf powder of spear grass, otherwise known as Imperata cylindrica (IC), was used to prepare activated carbon. The Imperata cylindrica activated carbon (ICAC) prepared was used for the removal of Congo red (CR) dye from aqueous solution. Operation parameters such as initial dye concentration, contact time, adsorbent dosage, pH, and temperature were studied in batch systems. Equilibrium was attained in 150 and 180?min at lowest and highest concentrations, respectively. Maximum adsorption was observed at pH 3. Quantum chemical studies suggested that the protonation of aniline groups and minimal molecular size at planar geometry coupled with electrostatic interaction enhances the adsorption at low pH. Adsorption data were tested using pseudo-first-order and second-order reaction kinetics; the latter was found to be more suitable with a coefficient of determination of ≥0.99. The adsorption process fits Langmuir isotherm model better than the Freundlich model, with a maximum monolayer coverage of 313?mgg^?1. This study shows that ICAC is effective in removing CR dye from aqueous solutions.     

Monitoring toxicity of an azo dye methyl red and a heavy metal Cu,using plant and animal bioassays

Toxicities of an azo dye methyl red and a heavy metal copper (Cu) were quantified, using growth and mortality as end points, in four plant species and three animal species by subjecting them to short-term (4 days for animals, 10 days for plants) static bioassays. Lemna aequinoctialis Welwitch (EC₅₀: 7–16 ppm) was found to be the most sensitive species for methyl red, Ceratophyllum demersum L. (EC₅₀: 25 ppm) and Lactuca sativa L. (EC₅₀: 56 ppm) were intermediate, while Oryza sativa L. shows reduction in seedling vigor (9–27%) of <50%, being the least sensitive amongst the tested plant species. Methyl red toxicity is almost 3–5-fold higher in growing medium (pH = 5.8–6.0), even at high nutrient levels, while Cu toxicity is higher in nutrient-poor alkaline medium at alkaline pH (8.3–8.7; EC₅₀: Ceratophyllum = 104–200 ppb; Lemna = 100–170 ppb) compared to nutrient-rich acidic medium (pH = 5.4–5.7; EC₅₀: Ceratophyllum = 2600–3175 ppb; Lemna = 4350–4715 ppb). Rice tolerance (EC₅₀: 6500 ppb) was found to be higher than hydrophytes while lettuce was most tolerant to Cu. Fish sensitivity toward the test chemicals was almost parallel to Ceratophyllum and Lemna [Gambusia affinis Baird and Gerard (LC₅₀: 250 ppb for Cu) and Poecilia reticulata Peters (LC₅₀: 24 ppm for methyl red)]. Similar to the plants, dye toxicity increased markedly (LC₅₀: 7 ppm) in the acidic medium (pH = 6.0). Amongst the tested organisms, Daphnia was found to be most sensitive to methyl red (EC₅₀: 6 ppm) while its sensitivity to Cu (EC₅₀: 230 ppb) was similar to hydrophytes and fish. Initially, the combination of dye and Cu (at their sublethal concentrations) had additive effects in duckweed, while dye concentration ruled afterward. These results indicate that hydrophytes and animals are equally sensitive toward the test chemicals. Dye toxicity in hydrophytes and fish was pH dependent, while in the case of Cu, it is related to the nutrient status of the growth medium of plants.     

Polychlorinated biphenyl (PCB) residues in European roe deer (Capreolus capreolus) and red deer (Cervus elaphus) from north-western Poland

The purpose of this study was to evaluate polychlorinated biphenyls (PCBs) contamination levels in roe and red deer from north-western Poland and to assess environmental pollution in this area. A quantitative analysis was conducted using a capillary gas chromatography/mass spectrometry method. The mean concentrations of ΣPCBs (sum of PCBs: 28, 52, 101, 138, 153, 180) in liver samples were 30.24±12.35 ng·g^?1 of lipid weight (l.w.) in roe deer and 60.13±14.23 ng·g^?1 l.w. in red deer, compared with 24.21±10.02 and 45.22±9.77 ng·g^?1 in the lungs of roe and red deer, respectively. PCBs 138, 153 and 180 were the dominant congeners in the liver samples of the analysed animals, whereas PCB 138 and 153 in the lungs. TEQs levels calculated for only dioxin-like PCBs were low: 0.32 and 0.29 pg WHO-PCB-TEQ·g^?1 fat in liver of red deer and roe deer, respectively. The mean PCB concentrations obtained in our study for organs of roe deer and red deer were several times lower than those reported elsewhere. These findings show that the investigated roe and red deer originated from an area with low levels of PCB contamination.     

Effect of red mud addition on the fractionation and bio-accessibility of Pb,Zn and As in combined contaminated soil

Using soil incubation experiments, the effect of red mud addition on the fractionation and bioaccessibility of Pb, Zn and As in combined contaminated soil was studied. The results showed that red mud addition could significantly decrease the concentration of HOAc-extractable Pb and Zn in soil. Compared with the control, 5% red mud addition could significantly reduce the concentrations of HOAc-extractable Pb and Zn in soil after 1, 2 and 3 months of incubation [62.5, 65.3 and 73.5% decrease (Pb), 56.7, 65.8 and 67.4% decrease (Zn)]. Whereas adding red mud could remarkably increase the concentrations of specific absorbed As and residual As in soil. The result of a simple bioavailability extraction test (SBET) indicated that all treatments with red mud addition markedly reduced the concentration of bioaccessible Zn but increased the concentration of bioaccessible As in soil, while having little effect on the concentration of bioaccessible Pb in soil. After 3 months incubation, all treatments including 1, 2 and 5% red mud addition reduced the concentration of bioaccessible Zn by 53.1–56.7% compared with the control, but increased the concentration of bioaccessible As by 1.81–6.25 times. The results suggested that red mud is an additive with potential for the remediation soil contaminated soil by combinations of heavy metals, although it should be added based on the different heavy metals in the soil. Combined use of red mud and hyperaccumulators to remediate heavy metal contaminated soil needs further study.