Decolorization of RBBR by plant cells and correlation with the transformation of PCBs

An extracellular H2O2-requiring Remazol Brilliant Blue R (RBBR) decolorizing enzyme activity was detected after cultivation of cells of various plant species both in liquid medium and when growing on agar plates containing RBBR. Level of the enzyme activity was compared with the ability to metabolize polychlorinated biphenyls (PCBs). The ability to decolorize RBBR was tested in the presence and absence of PCBs. The cultures with high PCB-transforming activity proved to exhibit RBBR oxidase much more resistant towards the influence of PCBs. In addition low activities of lignin peroxidase (LiP) and manganese dependent peroxidase (MnP) were detected in medium and in plant cells. No correlation of MnP and LiP activities with PCB degradation could be found. The RBBR decolorization could be used as a rough screening method for plant cultures able to metabolize PCBs.     

Separating habitat invasibility by alien plants from the actual level of invasion

Habitats vary considerably in the level of invasion (number or proportion of alien plant species they contain), which depends on local habitat properties, propagule pressure, and climate. To determine the invasibility (susceptibility to invasions) of different habitats, it is necessary to factor out the effects of any confounding variables such as propagule pressure and climate on the level of invasion. We used 20 468 vegetation plots from 32 habitats in the Czech Republic to compare the invasibility of different habitats. Using regression trees, the proportion of alien plants, including archaeophytes (prehistoric to medieval invaders) and neophytes (recent invaders), was related to variables representing habitat properties, propagule pressure, and climate. The propagule pressure was expressed as the proportion of surrounding urban and industrial or agricultural land, human population density, distance from a river, and history of human colonization in the region. Urban and industrial land use had a positive effect on the proportion of both archaeophytes and neophytes. Agricultural land use, higher population density, and longer history of human impact positively affected the proportion of archaeophytes. Disturbed human-made habitats with herbaceous vegetation were most invaded by both groups of aliens. Neophytes were also relatively common in disturbed woody vegetation, such as broad-leaved plantations, forest clearings, and riverine scrub. These habitats also had the highest proportion of aliens after removing the effect of propagule pressure and climate, indicating that they are not only the most invaded, but also most invasible. These habitats experience recurrent disturbances and are rich, at least temporarily, in available nutrients, which supports the hypothesis that fluctuating resources are the major cause of habitat invasibility. The least invaded habitats were mires and alpine-subalpine grasslands and scrub. After removing the effect of propagule pressure and climate, some habitats actually invaded at an intermediate level had very low proportions of aliens. This indicates that these habitats (e.g., dry, wet, and saline grasslands, base-rich fens, and broad-leaved deciduous woodlands) are resistant to invasion.     

Importance of species traits for species distribution in fragmented landscapes

Knowledge of the relationship between species traits and species distribution in fragmented landscapes is important for understanding current distribution patterns and as background information for predictive models of the effect of future landscape changes. The existing studies on the topic suffer from several drawbacks. First, they usually consider only traits related to dispersal ability and not growth. Furthermore, they do not apply phylogenetic corrections, and we thus do not know how considerations of phylogenetic relationships can alter the conclusions. Finally, they usually apply only one technique to calculate habitat isolation, and we do not know how other isolation measures would change the results. We studied the issues using 30 species forming congeneric pairs occurring in fragmented dry grasslands. We measured traits related to dispersal, survival, and growth in the species and recorded distribution of the species in 215 grassland fragments. We show many strong relationships between species traits related to both dispersal and growth and species distribution in the landscape, such as the positive relationship between habitat occupancy and anemochory and negative relationships between habitat occupancy and seed dormancy. The directions of these relationships, however, often change after application of phylogenetic correction. For example, more isolated habitats host species with smaller seeds. After phylogenetic correction, however, they turn out to host species with larger seeds. The conclusions also partly change depending on how we calculate habitat isolation. Specifically, habitat isolation calculated from occupied habitats only has the highest predictive power. This indicates slow dynamics of the species. All the results support the expectation that species traits have a high potential to explain patterns of species distribution in the landscape and that they can be used to build predictive models of species distribution. The specific conclusions are, however, dependent on the technique used, and we should carefully consider this when comparing among different studies. Since different techniques answer slightly different questions, we should attempt to use analyses both with and without phylogenetic correction and explore different isolation measures whenever possible and compare the results.     

Influence of the composition of the initial mixtures on the chemical composition,physicochemical properties and humic-like substances content of composts

The influence of the proportion of C- and N-rich raw materials (initial C/N ratio) and bulking agent on the chemical functional groups composition, humic-like substances (HS-like) content and physicochemical properties of composts was assessed. To achieve these goals, seven initial mixtures (BA1–6 and C1) of dog food (N-rich raw material) were composted with wheat flour (C-rich raw material). Composts were analyzed in terms of chemical functional groups, physicochemical, maturity and stability parameters.The C-rich raw material favored the formation of oxidized organic matter (OM) during the composting process, as suggested by the variation of the ratios of the peaks intensity of FT-IR spectra, corresponding to a decrease of the polysaccharides and an increase of aromatic and carboxyl-containing compounds. However, although with high proportion of C-rich raw material, mixtures with low initial C/N seems to have favored the accumulation of partially oxidized OM, which may have contributed to high electrical conductivity values in the final composts. Therefore, although favoring the partial transformation of OM into stabilized HS-like, initial mixtures with high proportion of C-rich raw material but with low initial C/N led to unstable composts.On the other hand, as long as a high percentage of bulking agent was used to promote the structure of biomass and consequently improve of the aeration conditions, low initial C/N was not a limiting factor of OM oxidation into extractable stabilized humic-like acids.     

Improved sample preparation and GC–MS analysis of priority organic pollutants

Mass spectrometry is a major tool for analysing organic pollutants. However, scientists often complain about laborious sample preparation. The development of new commercial high-resolution mass spectrometers gives a chance to improve simultaneously speed, reliability, and sensitivity of the analysis. Here, we used the time-of-flight high-resolution mass spectrometer Pegasus GC-HRT to identify and quantify 55 priority organic pollutants in water samples. This mass spectrometer has a high resolution of 50,000, a high mass accuracy of about 1 ppm and a very high acquisition rate of up to 200 full mass range spectra per second. 1 mL water samples were extracted with 1 mL dichloromethane. Results show that the sample preparation and analysis are achieved 30 times faster, requiring 1,000 times less water and 350 times less solvent than the classic 8270 method of the United States Environmental Protection Agency. The detection limit is 1 μg/L. The quantification limit is 10 μg/L. Our procedure, named accelerated water sample preparation, is simpler, faster, cheaper, safer and more reliable than 8270 Method.     

Phytoplankton community structure changes during autumn and spring in response to environmental variables in Methana,Saronikos Gulf,Greece

Environmental Science and Pollution Research - Phytoplankton community was investigated during two contrasting periods using offshore plankton samples in the volcanic area of Methana peninsula...     

Protective effect of gamma-oryzanol against manganese-induced toxicity in Drosophila melanogaster

Environmental Science and Pollution Research - Manganese (Mn) is an essential element that, in excess, seems to be involved in the development of different neurodegenerative conditions....     

Determination of atrazine in surface waters by combination of POCIS passive sampling and ELISA detection

Polar organic compound integrative samplers (POCIS) in combination with instrumental techniques such as LC-MS-MS were previously used to monitor environmental pollutants but the performance of alternative immunochemical methods such as ELISA (enzyme-linked immunosorbent assay) has been explored less. In the present study, POCIS technology was applied to surface water sampling in the Czech Republic, and ELISA was used as a detection technique for the herbicide atrazine. In the first study, 28 samples from streams around small municipal waste water treatment plants (WWTPs) were collected using two different devices (POCISpest and POCISpharm) over the course of 21 days. Elevated atrazine concentrations (up to 25 ng per POCIS) were found in samples down-stream of WWTPs. This observation was also confirmed in another two year study (4 sampling periods) investigating 7 river sites around a major city of Brno as well as the inlet and outlet of the city's WWTP. High atrazine levels were systematically determined at the outlet from the WWTPs (120-605 ng per POCIS). A decreasing trend in the atrazine concentrations in rivers around the city of Brno has been observed, with the highest levels observed within the first sampling period in spring 2007 (100-600 ng per POCIS, with an extreme value of 2760 ng per POCIS). Results of the atrazine ELISA were closely correlated with LC-MS/MS, which confirmed good applicability of ELISA as a cost-effective screening tool.     

Influence of local and regional Mediterranean meteorology on SO₂ ground-level concentrations in SE Spain

This work presents the results of a 4-year study on sulfur dioxide (SO(2)) ground-level concentrations in an area of southeastern Spain, the L'Alacantí region, where the cement industry is important and coke use extends to other industries as well. The main source of SO(2) emissions in the area was found to be a the Lepold cement plant (one of the two cement plants in the area). The high levels of SO(2) probably extend back to 1920 when this plant began operations. Both local and Mediterranean-scale meteorological processes influence the SO(2) ground-level concentration and together explain the dispersion dynamics of this pollutant. The location and topography of the study zone result in NW Atlantic advections and E-SE sea breezes being the dominant atmospheric circulation patterns in the area. Under stable meteorological conditions, minor local circulations are also relevant to the SO(2) concentration levels. The high frequency of local circulations determines a concentration pattern that changes during the day, with impacts occurring preferentially in a W-NW direction from the source at midday (sea breeze and strong thermal mixture), and in a SE direction at night. This causes the SO(2) concentrations to present well-defined diurnal cycles with well-differentiated shapes depending on the location of the sampling station relative to the source. The dependence of SO(2) 10 min levels on the wind origin and speed throughout the day has been evaluated by studying statistical parameters including P95, P50 and arithmetic mean. Exceedances occur under specific dispersion conditions at distances less than 1 km from the source. However, the source is traceable at larger distances and the levels are higher than typical urban ones. P95 was used as an estimator of the occurrence of larger levels or impacts. Leeward of NW winds and the source, at night and in early morning, P95 levels are comprised between 30 and 55 μg m(-3). In contrast, with SE winds and at midday, P95 levels stay at 17 μg m(-3). The same P95 was obtained for winds lower than 5 m s(-1), which represent 89% of the winds in the area. However, stronger winds can have P95 levels above 125 μg m(-3).     

Monitoring of Cr, Cu, Pb, V and Zn in polluted soils by laser induced breakdown spectroscopy (LIBS)

Laser Induced Breakdown Spectroscopy (LIBS) is a fast and multi-elemental analytical technique particularly suitable for the qualitative and quantitative analysis of heavy metals in solid samples, including environmental ones. Although LIBS is often recognised in the literature as a well-established analytical technique, results about quantitative analysis of elements in chemically complex matrices such as soils are quite contrasting. In this work, soil samples of various origins have been analyzed by LIBS and data compared to those obtained by Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES). The emission intensities of one selected line for each of the five analytes (i.e., Cr, Cu, Pb, V, and Zn) were normalized to the background signal, and plotted as a function of the concentration values previously determined by ICP-OES. Data showed a good linearity for all calibration lines drawn, and the correlation between ICP-OES and LIBS was confirmed by the satisfactory agreement obtained between the corresponding values. Consequently, LIBS method can be used at least for metal monitoring in soils. In this respect, a simple method for the estimation of the soil pollution degree by heavy metals, based on the determination of an anthropogenic index, was proposed and determined for Cr and Zn.