毛细管柱气相色谱法测定水质五氯酚

用乙酸酐衍生,正己烷液一液萃取,毛细管柱气相色谱-电子捕获检测器对地表水、废水中五氯酚进行了测定,确定五氯酚浓度范围在5．0—500μg/L之间时,样品的测定精度、回收率及方法检出限均能满足要求。     

PCDD/Fs-induced oxidative damage and antioxidant system responses in tobacco cell suspension cultures

Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) are ubiquitous contaminants and can be considerably accumulated by natural plants. In order to elucidate the biochemical and physiological responses of plant to PCDD/Fs, tobacco Bright Yellow-2 (BY-2) cells were selected as model plant and treated with time- and concentration-dependent PCDD/Fs. The toxic effect and oxidative stress caused by PCDD/Fs were evident, which could be indicted by the reduction in fresh mass, the increase in malondialdehyde (MDA) content, and the damage of tobacco cell ultrastructure. PCDD/Fs tolerance was correlated with changes in antioxidant system and hormones of tobacco cells. Superoxide dismutase (SOD) and peroxidase (POD) exhibited peak enzyme activities at the PCDD/Fs concentration of 1000 ng WHO₉₈-TEQ g⁻¹ fresh weight. Glutathione reductase (GR) enzyme activity increased monotonically at high level PCDD/Fs, but the activity of catalase (CAT) was only slightly affected at all treatment. Meanwhile, the exposure to PCDD/Fs resulted in the changes of hormones content. With the increase of exposure concentration of PCDD/Fs, the levels of indole-3-acetic acid (IAA) and abscisic acid (ABA) increased, whereas the concentration of jasmonates (JAs) decreased. The above results suggest that tobacco cells had the ability to cope with the oxidative stress induced by low concentration of PCDD/Fs through increasing the activities of antioxidant enzymes and alternating plant hormones levels. However, oxidative stress and toxicity would burst out when plant cells were exposed to the high levels of PCDD/Fs.     

Reducing the pollution risk of pesticide using nano networks induced by irradiation and hydrothermal treatment

Traditional pesticides (TP) often do not adhere tightly to crop foliage. They can easily enter the surrounding environment through precipitation and volatilization. This can result in the pollution of the surrounding soil, water, and air. To reduce pesticide pollution, we developed a loss-control pesticide (LCP) by adding attapulgite with a nano networks structure fabricated using high energy electron beam (HEEB) irradiation and hydrothermal treatment to TP. HEEB irradiation effectively dispersed originally aggregated attapulgite through modified thermal, charge, and physical effects. Hydrothermal treatment further enhanced the dispersion of attapulgite to form nano porous networks via thermal and wet expansion effects, which are beneficial for pesticide binding. An LCP has improved retention on crop leaf surfaces. It has a higher adhesion capacity, reduced leaching and volatilization, and extended residual activity compared with the TP formulation. The treatment increases the residual activity of pesticides on crop foliage and decreases environmental pollution.     

Silica nanoparticles and silver-doped silica nanoparticles induce endoplasmatic reticulum stress response and alter cytochrome P4501A activity

Engineered silica nanoparticles (SiO₂-NPs) find widespread application and may lead to exposure of humans and the environment. Here we compare the effects of SiO₂-NPs and SiO₂-NPs doped with silver (SiO₂-Ag-NPs) on survival and cellular function of human liver cells (Huh7) and Pimephales promelas (fathead minnow) fibroblast cells (FMH). In Huh7 cells we investigate effects on the endoplasmatic reticulum (ER), including ER stress, and interactions of nanoparticles (NPs) with metabolizing enzymes and efflux transporters. The NPs formed agglomerates/aggregates in cell culture media as revealed by SEM and TEM. SiO₂ and SiO₂-1% Ag-NPs were taken up into cells as demonstrated by agglomerates occurring in vesicular-like structures or freely dispersed in the cytosol. Cytotoxicity was more pronounced in Huh7 than in FMH cells, and increased with silver content in silver-doped NPs. Dissolved silver was the most significant factor for cytotoxicity. At toxic and non-cytotoxic concentrations SiO₂-NPs and SiO₂-1% Ag-NPs induced perturbations in the function of ER. In Huh7 cells NPs induced the unfolded protein response (UPR), or ER stress response, as demonstrated in induced expression of BiP and splicing of XBP1 mRNA, two selective markers of ER stress. Additionally, SiO₂-1% Ag-NPs and AgNO₃ induced reactive oxygen species. Pre-treatment of Huh7 cells with SiO₂-1% Ag-NPs followed by exposure to the inducer benzo(a)pyrene caused a significant reduced induction of CYP1A activity. NPs did not alter the activity of ABC transporters. These data demonstrate for the first time that SiO₂-NPs and SiO₂-1% Ag-NPs result in perturbations of the ER leading to the ER stress response. This represents a novel and significant cellular signalling pathway contributing to the cytotoxicity of NPs.     

Seasonal variation of organochlorine contaminants in bonito (Sarda sarda L. 1758) and anchovy (Engraulis encrasicolus L. 1758) in Black Sea region, Turkey

The concentrations of indicator polychlorinated biphenyls (PCBs) and organochlorine insecticides were determined in bonito (Sardasarda L. 1758) and anchovy (Engraulisencrasicolus L. 1758) from the Black Sea, Turkey. Concentrations of total indicator PCBs ranged between <1-17.0 in bonito, and <1-17.5 ng/g fresh weight in anchovy, and total of 1,1,1-trichloro-2,2-bis-chlorophenyl-ethane and its metabolites’ (DDTs) concentrations ranged between 13.4-26.3, and 2.96-19.0 ng/g fresh weight in bonito and anchovy respectively. PCB 52, p,p′-DDE and endosulfan (α + β) were found dominant in both of the fish species. Except endosulfan, and some DDT metabolites, none of the studied organochlorine pesticides was detected in the fish samples. Concentrations of PCBs in anchovy were found higher than those in bonito, whereas DDT and endosulfan concentrations were found similar in both of the fish species. All of the fish samples had residue concentrations below the maximum residue limits (MRL) recommended by FAO/WHO Codex Alimentarius Commission.     

Preparation of Alginic Acid and Metal Alginate from Algae and their Comparative Study

Alginic acid and metal alginates are prepared from fresh algae using extraction method. A FTIR spectrum indicates that alginic acid is converted into the metal alginate. Comparing calcium and cobalt alginates, asymmetric stretching of free carboxyl group of calcium alginate at 1630 cm⁻¹ is shifted to 1585 cm⁻¹ in cobalt alginate, due to the change of charge density, radius and atomic weight of the cation, creating a new environment around the carbonyl group. The strong exothermic peak of alginic acid in DSC thermogram indicates the decomposition of biopolymer, whereas strong exothermic peak of metal alginate in DSC thermogram attributed to the decomposition of biopolymer and formation of respective carbonate. Based on DSC study, the decomposition of cobalt alginate occurs at higher temperature comparing to those of sodium and calcium alginate, which may conclude into the higher stability of cobalt alginate. TGA results reveal that, cobalt alginate is more stable than calcium and sodium alginate at 300 °C temperature. Surface morphology (at same magnification), as well as porosity (%) and pore size distribution results change with metals present in different metal alginates.     

Injection Molded Biocomposites from Soy Protein Based Bioplastic and Short Industrial Hemp Fiber

Biocomposites from soy based bioplastic and chopped industrial hemp fiber were fabricated using twin-screw extrusion and injection molding process. Soy based bioplastics were prepared through cooking with plasticizer and blending with biodegradable poly(ester amide). Mechanical, thermal properties and fracture surface morphology of the “green”/biocomposites were evaluated with universal testing system (UTS), dynamic mechanical analysis (DMA), Environmental Scanning Electron Microscopy (ESEM). It was found that the tensile strength and modulus, flexural strength and modulus, impact strength and heat deflection temperature of industrial hemp fiber reinforced biocomposites significantly improved. The fracture surfaces showed no signs of matrix on the fiber surface suggesting poor interfacial adhesion.     

石墨烯/血红素仿生涂层促进电活性微生物产电的效应和机理研究

阳极输出效率是决定生物电化学系统(BESs)能否实现工程化应用的基础和关键.但微生物/阳极界面的低效电子传递阻碍了 BESs整体输出效率的进一步提升.本研究通过模拟细胞色素c构建了一种石墨烯/血红素(GN/Hemin)复合仿生材料修饰的高性能BESs阳极.通过监测电活性菌ShewanellaloihicaPV-4的电能...     

Urban geochemistry: research strategies to assist risk assessment and remediation of brownfield sites in urban areas

Urban geochemical maps of Wolverhampton and Nottingham, based on multielement analysis of surface soils, have shown distribution patterns of “total” metals concentrations relating to past and present industrial and domestic land use and transport systems. Several methods have been used to estimate the solubility and potential bioavailability of metals, their mineral forms and potential risks to urban population groups. These include sequential chemical extraction, soil pore water extraction and analysis, mineralogical analysis by scanning electron microscopy, source apportionment by lead isotope analysis and the development of models to predict metal uptake by homegrown vegetables to provide an estimate of risk from metal consumption and exposure. The results from these research strategies have been integrated with a geographical information system (GIS) to provide data for future land-use planning.     

Comparative growth response of two varieties of <Emphasis Type="Italic">Vigna radiata</Emphasis> L. (var. PDM 54 and var. NM 1) grown on different tannery sludge applications: effects of treated wastewater and ground water used for irrigation

This study evaluates the possibility of using contaminated soil by treated tannery wastewater and the use of tannery sludge in agriculture. The plants of Vigna radiata var. PDM 54 grown on contaminated soil and irrigated with ground water have not shown the translocation of toxic metal (Cr) in the upper part. The biomass of the plant increased when irrigated with treated tannery wastewater compared to ground water, whereas no significant change was observed in chlorophyll and protein contents. In both the varieties (var. PDM 54 and var. NM 1) of V. radiata grown on tannery sludge amendments, the growth parameters exhibited a pronounced positive growth response up to 35% tannery sludge amendments compared with the plants grown on garden soil. Despite the Cr accumulation at lower amendments, no toxicity symptoms were observed in both the varieties of the plants. Higher amendments affected various growth parameters, NR activity, and carbohydrate content of the plants. The results suggest that the plants of V. radiata (var. PDM 54) may be grown on contaminated soil or lower sludge amendments and irrigated with ground water. No translocation of toxic metal Cr was found in the seeds of the plants grown in up to 25% tannery sludge. However, periodical monitoring is required before the consumption of seeds. Overall, the results showed that plant growth patterns were influenced to some extent by the level of soil contamination and the water used for irrigation.