Synthesis and Characterization of Chitosan-Acrylic Acid Based Hydrogels and Investigation the Properties of Bilayered Design with Incorporated Alginate Beads

Journal of Polymers and the Environment - The paper presents the synthesis of hydrogels via free-radical polymerization, based on Chitosan (CS) grafted with Acrylic acid (AA), using a two-step...     

Evaluation of potential human health risks from exposure to volatile organic compounds in contaminated urban groundwater in the Sava river aquifer,Belgrade, Serbia

Environmental Geochemistry and Health - The oil pollutant in the Sava River aquifer in the residential area of Belgrade, Serbia was investigated in order to analyze the extent, origin and spatial...     

Land Degradation on Barren Hills: A Case Study in Northeast Vietnam

The term "barren hills" has been a keyword for land degradation in the uplands of Vietnam for over a decade. Nevertheless, the "barren" land is still not adequately ecologically characterized. In this work, we analyze land use-induced changes in vegetation and soil properties along a sequence of barren hills types formed on one physiotope. The study is undertaken in the Bac Kan province, one of the poorest upland regions where livestock plays an important role. A transition from an old-growth laurel forest to a sparse manmade grassland is characterized by a total of 177 species, rapid species turnover, and discrete dominants, and an overwhelming effect of disturbance history on both soil and vegetation patterning. Land degradation is most apparent in land use-induced maintenance of arrested successions, and the regeneration course is shifted towards drier formations. We hypothesize a conceptual model as an aid to understanding the process of early fallow differentiation in response to the patterned, fine-scale disturbances. The larger-scale implications of the observed trends in regeneration potentials deviation, and, in particular, the effect of water buffaloes in halting fallow successions, are discussed.     

Multivariate toxicity profiles and QSAR modeling of non-dioxin-like PCBs--an investigation of in vitro screening data from ultra-pure congeners

The non-dioxin-like PCBs (NDL-PCBs) found in food and human samples have a complex spectrum of adverse effects, but lack a detailed risk assessment. The toxicity profiles of 21 carefully selected PCBs (19 NDL-PCBs) were identified by in vitro screening in 17 different assays on specific endpoints related to neurotoxicity, endocrine disruption and tumor promotion. To ensure that the test results were not affected by polychlorinated dioxins, dibenzofurans or DL-PCB contaminants, the NDL-PCB congeners were thoroughly purified before testing. Principal component analysis (PCA) was used to derive general toxicity profiles from the in vitro screening data. The toxicity profiles indicated different structure-activity relationships (SAR) and distinct mechanisms of action. The analysis also indicated that the NDL-PCBs could be divided into two groups. The first group included generally smaller, ortho-substituted congeners, comprising PCB 28, 47, 51, 52, 53, 95, 100, 101, 104 and 136, with PCB 95, 101 and 136 as generally being most active. The second group comprising PCB 19, 74, 118, 122, 128, 138, 153, 170, 180 and 190 had lower biological activity in many of the assays, except for three endocrine-related assays. The most abundant congeners, PCB 138, 153, 170, 180 and 190, cluster in the second group, and thereby show similar SAR. Two quantitative structure-activity relationship (QSAR) models could be developed that added information to the SAR and could aid in risk assessments of NDL-PCBs. The QSAR models predicted a number of congeners as active and among these e.g., PCB 18, 25, 45 and 49 have been found in food or human samples.     

Concentration of heavy metals in various children's herbal tea types and their correlations

This investigation was undertaken to determine the concentrations of cadmium, lead, mercury, zinc, copper and magnesium in six tea types used as children's tea. Six types of tea of different herbal composition used for children's consumption (T1, T2, T3, T4, T5 and T6) were analyzed in three subsequent collections. The analysis of cadmium showed that the concentration was very similar in all types of children's tea, ranging from 0.233 to 0.369 mg/kg. Lead concentrations were in the range of 0.340–1.564 mg/kg without any significant differences. The analysis of mercury detected very low concentration of this metal in all samples (0.002–0.004 mg/kg). In zinc, the values ranged from 36.633 to 71.711 mg/kg, with significant differences (p < 0.001) according to tea type. Copper concentration was 10.089–30.178 mg/kg with the highest value in T4. The concentration of magnesium was significantly higher in tea T1 and T2 (102.311 and 129.422 mg/kg) in comparison with other tea types where the level was 19.811–37.411 mg/kg. The maximum tolerable limit determined by Codex Alimentarius was not exceeded in any sample. In general, correlation analysis detected high positive correlation between cadmium and lead (r = 0.89), cadmium and mercury (r = 0.92) and between lead and mercury (r = 0.77).     

Concentrations, distributions and critical level exceedance assessment of SO2, NO2 and O3 in South Africa

South Africa has been identified as a source of industrial pollution that is significant at a global scale. This study was designed to provide quantitative information, by direct measurement, across northeastern South Africa, which includes the highly industrialised Mpumalanga Highveld. The specific aim of the study was to evaluate whether or not acidic atmospheric pollution poses a threat to soils, plants and water bodies of South Africa. To address this aim, a network of 37 passive sampling sites was established to measure monthly mean concentrations of near-surface SO₂, NO₂ and ozone. The area covered extended over the northern and eastern interior of South Africa while avoiding sources of local emissions such as towns, mines and highways. The field campaign was conducted between August 2005 and September 2007. Spatial distributions and temporal trends for these pollutant gases were assessed. Critical levels analysis comparisons were made against applicable air quality standards, guidelines and limits to evaluate the potential for adverse atmospheric pollution impacts on regional environments. The assessment indicates that only in the central source area of the South African industrial Highveld are some levels exceeded. In remote areas, including the sensitive forested regions of the Drakensberg escarpment, pollutant concentrations are below the critical thresholds for environmental damage.     

Aufnahme und Verteilung von Trichloressigsäure in Trieben Norwegischer Fichte

To elucidate the uptake of TCA by roots and its distribution in Norway spruce shoots, experiments with [¹⁴C]TCA were carried out in combination with radioactivity measurements after combustion, and with autoradiographic detection methods. It was shown that the uptake of TCA by spruce shoots is faster during the growth period in June than in the post-growth period in September. A high uptake of radioactivity was observed in the current-year needles, especially in the top of them, and in the corc cambium of the one-year-old wooden parts of the spruce shoots. The results of our experiments suggest uptake of TCA into spruce needles from the soil water with the transpiration stream.     

Determination of 226Ra at ultratrace level in mineral water samples by sector field inductively coupled plasma mass spectrometry

An analytical procedure has been proposed for the determination of (226)Ra at the low femtogram per ml concentration level in mineral water samples using double focusing sector field ICP-MS (ICP-SFMS). For the pre-concentration and separation of radium from the matrix elements in water a tandem of a laboratory-prepared filter, based on MnO(2), and Eichrom "Sr-specific" resin was used. The recovery of the method was determined to be 70.5%. The limit of detection for (226)Ra determination was 0.02 fg ml(-1), including a pre-concentration factor of 10. In addition, uranium concentration and uranium isotope ratios were measured by ICP-SFMS. In several mineral water samples with a relatively high uranium content, (226)Ra concentrations were found between 0.7-15 fg ml(-1). The effective dose of the contribution was calculated using the radionuclide concentration and dose conversion factors from the World Health Organization, WHO (1993). Assuming a mineral water consumption of 2 l d(-1), a slightly higher calculated dose than the suggested limit for drinking water (0.1 mSv y(-1)) was found in some samples.     

Beauty ranking of mammalian species kept in the Prague Zoo: does beauty of animals increase the respondents’ willingness to protect them?

Aesthetic preferences for animals correspond with the species’ presence in the worldwide zoos and influence the conservation priorities. Here, we investigated the relationship between the willingness of respondents to protect mammals and some attributed characteristics such as their aesthetic beauty. Further, several methodological aspects of measuring mammalian beauty were assessed. Animal beauty was associated not only with the respondents’ willingness to protect the species but also with its attributed dangerousness and usefulness. We found that the most preferred animals were carnivores and ungulates, whilst smaller species of rodents and afrosoricids were unpopular. The main characteristics determining that an animal will be ranked as beautiful were complex fur pattern and body shape. We demonstrated that the position of mammalian species along the ‘beauty’ axis is surprisingly stable, no matter the form (illustrations vs photographs), context of stimulus presentation (several number of stimuli per family vs one randomly selected species per family), or the method of beauty evaluation (relative order vs Likert’s scale).     

Nanotechnology and groundwater remediation: A step forward in technology understanding

Nanotechnology application to contaminated site remediation, and especially the use of nanoscale zero‐valent iron particles to treat volatile organic compound (VOC)‐impacted groundwater, is now recognized as a promising solution for cost‐effective in situ treatment. Results obtained during numerous pilot tests undertaken by Golder Associates between 2003 and 2005 in North America (United States and Canada) and Europe have been used to present a synthetic cross‐comparison of technology dynamics. The importance of a comprehensive understanding of the site‐specific geological, hydrogeological, and geochemical conditions, the selection of appropriate nanoscale particles, the importance of monitoring geochemical parameters during technology application, and the potential of nanoparticle impact on microbial activity are discussed in this article. The variable technology dynamics obtained during six pilot tests (selected among numerous other tests) are then presented and discussed. © 2006 Wiley Periodicals, Inc.