Oxidative stress, cytoxicity, and cell mortality induced by nano-sized lead in aqueous suspensions

This paper reports on the effect of aqueous and nano-particulated Pb on oxidative stress (lipid peroxidation), cytoxicity, and cell mortality. As determined by the Thiobarbituric Acid Reactive Substances (TBARS) method, only 6 h after incubation aqueous suspensions bearing nano-sized PbO₂, soluble Pb(II), and brain-homogenate only suspensions, were determined to contain as much as ca. 7, 5, and 1 nmol TBARS mg protein⁻¹, respectively. Exposure of human cells (central nervous system, prostate, leukemia, colon, breast, lung cells) to nano-PbO₂ led to cell-growth inhibition values (%) ca. ≤18.7%. Finally, as estimated by the Artemia salina test, cell mortality values were found to show high-survival larvae rates. Microscopic observations revealed that Pb particles were swallowed, but caused no mortality, however.     

Coffee husk composting: An investigation of the process using molecular and non-molecular tools

Various parameters were measured during a 90-day composting process of coffee husk with cow dung (Pile 1), with fruit/vegetable wastes (Pile 2) and coffee husk alone (Pile 3). Samples were collected on days 0, 32 and 90 for chemical and microbiological analyses. C/N ratios of Piles 1 and 2 decreased significantly over the 90 days. The highest bacterial counts at the start of the process and highest actinobacterial counts at the end of the process (Piles 1 and 2) indicated microbial succession with concomitant production of compost relevant enzymes. Denaturing gradient gel electrophoresis of rDNA and COMPOCHIP microarray analysis indicated distinctive community shifts during the composting process, with day 0 samples clustering separately from the 32 and 90-day samples. This study, using a multi-parameter approach, has revealed differences in quality and species diversity of the three composts.     

What is the acceptable margin of error for the oxygen uptake method in evaluating the reactivity of organic waste?

The acceptable margin of error for the organic waste reactivity measured by the oxygen uptake method was assessed. Oxygen uptake was determined by the Dynamic Respiration Index (DRI) (mgO₂/kgVS h). The composed uncertainty (uC) of the experimental set up used for the DRI test was evaluated and the uncertainty (u) of all the components of the apparatus was evaluated. A procedure for calculating the uC of the apparatus is proposed. The components affecting the uC of the DRI to a more significant extent were the one of the oxygen mass rate and the u of the amount of VS in the sample analyzed. For a confidence level of 99.73%, the extended uC (UC) interval for a DRI = 1024 mgO₂/kgVS h was ±440 mgO₂/kgVS h, whereas for a DRI = 3489 mgO₂/kgVS h, the UC interval was ±1288 mgO₂/kgVS h. When oxygen consumption and VS content become lower than 600 mgO₂/h and 0.9 kg, respectively, the UC interval is similar to the measured DRI.     

Contaminant Exposure of Barn Swallows Nesting on Bayou D'Inde, Calcasieu Estuary, Louisiana, USA

Current and historical point source discharges, storm water runoff, and accidental spills have contaminated the water, sediment, and biota within the Calcasieu Estuary in southwestern Louisiana. In 2003, barn swallow (Hirundo rustica) eggs and nestlings were collected beneath two bridges that cross Bayou d′Inde, the most contaminated waterway within the Calcasieu Estuary. Samples were also collected from a bridge over Bayou Teche, a reference site in south central Louisiana. Polychlorinated biphenyl (PCB) concentrations in barn swallow eggs and nestlings were significantly higher at the downstream site on Bayou d′Inde (2.8 μ g/g PCBs in eggs and 1.5 μ g/g PCBs in nestlings) than at the other two sites (< 0.2 μ g/g PCBs in eggs and nestlings at both sites). Ethoxyresorufin-O-dealkylase activity in nestling livers was significantly higher at the downstream site on Bayou d′Inde (50 pmol/min/mg) compared to the other two locations (24 pmol/min/mg, each), probably because of exposure to PCBs. Polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofuran concentrations in eggs and polycyclic aromatic hydrocarbons in nestlings were at background concentrations at all sites. Trace element concentrations in barn swallow eggs and nestling livers were at background levels and did not differ among the three sites. A biomarker of DNA damage did not differ among sites.     

Integrated Ambient and Microenvironment Model for Estimation of PM10 Exposures of Children in Annual and Episode Settings

Particulate matter air pollution is estimated to cause in the order of 350,000 excess deaths in the European Union calling for policy development and evaluation tools. In the current work, a model for PM₁₀ exposures of children is developed using microenvironment time activities and infiltration of ambient pollution indoors, both evaluated against observations earlier and integrated with city-wide air quality models in the current work. The model is demonstrated using data from two cities in Italy. High-end short-term exposures are characterized by an episode-day situation in Turin, and annual mean exposures in downtown Bologna. The air quality model was unable to capture the highest levels during the episode, and therefore, the exposure model was adjusted using observed–modeled ratio from a monitoring station. Air quality model performance for the annual levels was significantly better. Annual exposure variability within the target population was 1.5-fold in the downtown area Bologna and tenfold during the episode day in Turin.     

微乳法制备Fe-TiO_2纳米晶复合体及光催化性能

采用微乳法制备铁掺杂TiO2纳米晶（Fe-TiO2）复合体,通过热重-差热（TG-DTA）、X射线衍射（XRD）、扫描电镜（SEM）和紫外漫反射光谱（DRS）等对其结构和形态进行表征;以亚甲基蓝溶液（MB）为标准模拟降解物,对Fe-TiO2,纯TiO2和P25光催化降解性能进行评价。结果表明,Fe-TiO2的光催化活性明显〉P25,原因是Fe掺杂不仅能抑制TiO2晶粒生长,提高TiO2的热稳定性和比表面积,而且能够拓展TiO2的吸收波长范围至可见光区,提高了Ti3＋离子浓度,降低了光生载流子的复合几率。     

溶胶-凝胶法制备复合光催化剂（MWNTs/TiO_2）工艺条件的研究

以多壁碳纳米管（MWNTs）为载体,在煅烧温度200~900℃、煅烧时间1~7 h、溶胶体系pH值为2~10的工艺条件下,采用溶胶-凝胶法制备复合光催化剂（MWNTs/TiO2）。通过其对甲基橙的光催化降解效果对比,评价各种复合光催化剂催化活性之间的差异,结果表明,随着煅烧温度的升高,复合光催化剂中纳米TiO2的晶型由锐钛型逐渐向金红石型转变,500℃时为2种晶型的混合相;pH值为2的强酸性条件有利于形成金红石晶型,pH值为5的中性及弱酸性条件则有利于形成锐钛型,而pH值为3时为2种晶型的混合相;在煅烧温度500℃、煅烧时间3 h、溶胶凝胶体系pH值为3的最佳制备工艺条件下,复合光催化剂催化活性最高,借助扫描电镜发现其TiO2均匀地包覆在多壁碳纳米管管壁上。     

常温下IC反应器启动过程中的颗粒污泥性能研究

在常温下用自配葡萄糖废水启动IC反应器,研究了厌氧颗粒污泥的形成过程和特性。IC反应器进水浓度为3 000 mg COD/L,水温为14.5～26℃,25 d内形成了颗粒污泥。结果表明,随着运行时间和容积负荷的增加,颗粒污泥粒径逐渐增大。反应器启动完成后,反应器中2 mm的颗粒污泥增加到6.6%,0.3 mm的颗粒从57.7%减少到39.4%;VSS浓度从24.7 g/L上升到48.2 g/L;VSS/SS从34.4%增加到72.8%。颗粒污泥的沉降速度与颗粒粒径成正比,0.3～3 mm的颗粒污泥的沉降速度介于34.05～109.75 m/h之间,具有良好的沉降性能。初始接种污泥几乎没有产甲烷活性,与第30 d的初期颗粒污泥相比,成熟的颗粒污泥的产甲烷活性提高了46.7%。     

人类活动对上海市生物多样性空间格局的影响

为了揭示人类活动对城市化地区生物多样性空间格局的影响及其景观生态学机制,文章将上海市作为研究对象,选择3个人类活动指标、3个主要类型生态系统的4个景观特征指标与8个生物多样性指标,探讨人类活动强度、野生动植物生境景观特征及生物多样性三者之间的相互关系。结果显示,人口增长和城市扩张对上海市生物多样性的空间格局产生了显著影响。在上海地区,人口密度较高、交通较为发达的区域,湿地和农田的景观连续性较低,生物多样性也较低,外来入侵物种丰度较高。这表明在快速城市化过程中,人类活动通过改变野生动植物栖息地景观质量来对区域生物多样性产生影响。本研究还显示,经济发展并非一定对生物多样性具有负面影响。因此,在保持经济发展的同时,通过优化产业结构与加强生物多样性管理,可实现对生物多样性有效保护。     

苯并[a]芘对马氏珠母贝鳃组织抗氧化酶活性的影响

将马氏珠母贝（Pinctada martensi）暴露于不同质量浓度（1、4和8μg.L-1）苯并[a]芘B[a]P中,检测暴露后第3、7和10天后,马氏珠母贝鳃组织抗氧化酶（超氧化物歧化酶SOD、谷胱甘肽硫转移酶GST和过氧化氢酶CAT）对苯并[a]芘胁迫的生态毒理效应。结果表明：暴露时间为3、7 d时,SOD活性无明显变化,随着暴露时间的延长,SOD活性在第10天时被激活;在胁迫初期,GST活性被激活,随后表现出逐渐降低的趋势,在暴露后10 d,不同质量浓度组GST活性变化趋于稳定。当暴露质量浓度相同时,表现出明显的时—效关系;而CAT活性在第7天被激活,随着时间的延长,高质量浓度（4和8μg.L-1）组表现出先升高后下降的趋势,并表现出一定的时-效关系。SOD、GST和CAT均可作为B[a]P污染的生物标志物,活性变化相对于SOD,GST和CAT对B[a]P的胁迫更加敏感。