Active biomonitoring with wet and dry moss: a case study in an urban area

Active biomonitoring of the air quality in Belgrade, Serbia, was performed using the moss Sphagnum girgensohnii. Moss bags were exposed in parallel with and without irrigation for 3 and 6 months, respectively, at three different sites. Twenty-nine elements were determined in the exposed moss samples by INAA. For all exposure periods, higher uptake in the irrigated moss bags was evident for Al, Cr, Fe, Zn and Sr. Elements such as Cl, K, Rb and Cs were depleted in the moss tissue during the time of exposure. For most of the elements the accumulation after 6 months exceeded that observed after 3 months.     

Spatially explicit modeling of overstory manipulations in young forests: Effects on stand structure and light

Young forests can be manipulated in diverse ways to enhance their ecological values. We used stem maps from two dense, second-growth stands in western Washington and a spatially explicit light model (tRAYci) to simulate effects of five silvicultural manipulations on diameter distribution, species composition, spatial patterning, and light availability. Each treatment removed 30% of the basal area, but differed in how trees were selected for removal. Three primary treatments were thin from below (removing the smallest trees), random thin (removing trees randomly), and gap creation (removing all trees in circles ∼1 tree height in diameter). Two additional treatments combined elements of these approaches: random ecological thin (a mixture of thin from below and random thin) and structured ecological thin (a mixture of thin from below and gap creation).     

Medical geochemistry research in Spišsko-Gemerské rudohorie Mts., Slovakia

This study presents an assessment of the potential impact of geological contamination of the environment on the health of the population in Spišsko-Gemerské rudohorie Mts. (SGR Mts.). The concentration levels of potentially toxic elements (mainly As, Cd, Cu, Hg, Pb, Sb, and Zn) were determined in soils, groundwater, surface water, and stream sediments as well as in the food chain (locally grown vegetables). A medical study included some 30 health indicators for all 98 municipalities of the study area. The As and Sb contents in human fluids and tissues were analyzed in one municipality identified to be at the highest risk. Based on element content, environmental and health risks were calculated for respective municipalities. Out of 98 municipalities 14 were characterized with extremely high environmental risk and 10 were characterized with very high carcinogenic risk from arsenic (groundwater). Extensive statistical analysis of geochemical data (element contents in soils, groundwater, surface water, and stream sediments) and health indicators was performed. Significant correlations between element contents in the geological environment and health indicators, mainly cancer and cardiovascular diseases, were identified. Biological monitoring has confirmed the transfer of elements from the geological environment to human fluids and tissues as well as to the local food chain.     

Health risk assessment maps for arsenic groundwater content: application of national geochemical databases

This investigation assesses the feasibility of calculating and visualizing health risk estimates from exposure to groundwater contaminated with arsenic (As) using data from national geochemical databases. The potential health risk associated with As-contaminated groundwater was assessed based on an elaboration of existing geochemical data in accordance with accepted methodological procedures established for human health risk assessment (U.S. Environmental Protection Agency methodology). A screening analysis approach was used for estimating the contribution of As to the total chronic health risk from exposure to groundwater contaminated with potentially toxic elements, including As, Ba, Cd, Cu, Hg, Pb, Sb, Se and Zn, and the results indicate that As contributes significantly (>50%) to this total health chronic risk in about 10% of Slovak territory. Based on the calculation of the potential risk level by exposure modelling, increased chronic as well as carcinogenic risk levels (medium to high) were documented in approximately 0.2 and 11% of the total Slovak area, respectively. The areas characterized by high health risk levels are mainly those geogenically contaminated. High and very high carcinogenic risk was determined in 34 of 79 districts and in 528 of 2924 municipalities.     

Analysis of emergency situations at municipal solid waste landfills

Journal of Material Cycles and Waste Management - This work focuses on the issue of emergency prevention in the operation of municipal solid waste landfills. In this work, an emergency is...     

An Analysis of Secondary Pollutants in Buenos Aires City

Air pollutant concentrations from a monitoring campaign in Buenos Aires City, Argentina, are used to investigate the relationships between ambient levels of ozone (O₃), nitric oxide (NO) and nitrogen dioxide (NO₂) as a function of NO _x (=NO + NO₂). This campaign undertaken by the electricity sector was aimed at elucidating the apportionment of thermal power plants to air quality deterioration. Concentrations of carbon monoxide (CO) and sulphur dioxide (SO₂) were also registered. Photo stationary state (PSS) of the NO, NO₂, O₃ and peroxy radicals species has been analysed. The ‘oxidant’ level concept has been introduced, OX (=O₃ + NO₂), which varies with the level of NO _x . It is shown that this level is made up of NO _x -independent and NO _x -dependent contributions. The former is a regional contribution that equates the background O₃ level, whereas the latter is a local contribution that correlates with the level of primary pollution. Furthermore, the anticorrelation between NO₂ and O₃ levels, which is a characteristic of the atmospheric photo stationary cycle has been verified.The analysis of the concentration of the primary pollutants CO and NO strongly suggests that the vehicle traffic is the principal source of them. Levels of continuous measurements of SO₂ for Buenos Aires City are reported in this work as a complement of previously published results.     

Determination of microbiological contamination,antibacterial and antioxidant activities of natural plant hazelnut (Corylus avellana L.) pollen

The aim of our study is to determine microbial contamination, antibacterial and antioxidant activities of 14 pollen samples of Corylus avellana collected from different locations in Slovakia. Microbiological analysis was carried out in two steps: microbiological assays and studies of antibacterial activity of pollen extracts. The antimicrobial properties of pollen extracts were carried out with the disc-diffusion method. Methanol (70%), ethanol (70%) and distilled water were used for pollen extracts. Five strains of bacteria such as gram-negative (Salmonella enterica subsp. enterica CCM 3807, Escherichia coli CCM 2024, and Yersinia enterocolitica CCM 5671) and gram-positive (Staphylococcus aureus CCM 2461 and Bacillus thuringiensis CCM 19T) were tested. Antioxidant activity of pollen extracts was determined by the DPPH method. Bacterial analysis includes the determination of the total bacterial count ranged from 4.08 to 4.61 log CFU g^?1, mesophilic aerobic bacteria ranged from 3.40 to 4.89 log CFU g^?1, mesophilic anaerobic bacteria ranged from 3.20 to 4.52 log CFU g^?1, coliform bacteria ranged from 3.30 to 4.55 log CFU g^?1, yeasts and filamentous fungi ranged from 3.00 to 3.56 log CFU g^?1. Microscopic filamentous fungi Aspergillus spp., Alternaria spp., Penicillium spp., Cladosporium spp., Rhizopus spp., and Paecylomyces spp. were isolated from hazelnut pollen. Yersinia enterocolitica was the most sensitive strain among ethanolic and methanolic pollen hazelnut extracts. Staphylococcus aureus was the most sensitive strain against aqueous hazelnut pollen extracts. We determined the following sensitivity against ethanol pollen extracts respectively: Yersinia enterocolitica?>?Salmonella enterica?>?Staphylococcus aureus?>?Bacillus thuringiensis?>?Escherichia coli. Methanol pollen extracts had shown following sensitivity: Yersinia enterocolitica?>?Salmonella enterica?>?Escherichia coli?>?Staphylococcus aureus?>?Bacillus thuringiensis. Aqueous extracts had shown the following sensitivity: Staphylococcus aureus?>?Salmonella enterica?>?Escherichia coli?>?Bacillus thuringiensis?>?Yersinia enterocolitica. Hazelnut pollen extracts have over 82% antioxidant capacity in samples from non-urban zones. An elevated level of antioxidant potential in the pollen is determined by its biological properties conditioned by biologically active substances. DPPH method allowed characterizing pollen as a source of antioxidants.     

Influence of Short Central PEO Segment on Hydrolytic and Enzymatic Degradation of Triblock PCL Copolymers

Hydrolytic, enzymatic degradation and composting under controlled conditions of series of triblock PCL/PEO copolymers, PCEC, with central short PEO block (M _n 400 g/mol) are presented and compared with homopolymer (PCL). The PCEC copolymers, synthesized via ring-opening polymerization of ε-caprolactone, were characterized by ¹H NMR, quantitative ¹³C NMR, GPC, DSC and WAXS. The introduction of the PEO central segment (<?2 wt%) in PCL chains significantly affected thermal degradation and crystallization behavior, while the hydrophobicity was slightly reduced as confirmed by water absorption and moisture uptake experiments. Hydrolytic degradation studies in phosphate buffer after 8 weeks indicated a small weight loss, while FTIR analysis detected changes in crystallinity indexes and GPC measurements revealed bulk degradation. Enzymatic degradation tested by cell-free extracts containing Pseudomonas aeruginosa PAO1 confirmed high enzyme activity throughout the surface causing morphological changes detected by optical microscopy and AFM analysis. The changes in roughness of polymer films revealed surface erosion mechanism of enzymatic degradation. Copolymer with the highest content of PEO segment and the lowest molecular weight showed better degradation ability compared to PCL and other copolymers. Furthermore, composting of polymer films in a model compost system at 37 °C resulted in significant degradation of the all synthesized block copolymers.     

Photocatalytic reduction of carbon dioxide over Cu/TiO<Subscript>2</Subscript> photocatalysts

The photocatalytic reduction of CO₂ with H₂O was investigated using Cu/TiO₂ photocatalysts in aqueous solution. For this purpose, Cu/TiO₂ photocatalysts (with 0.2, 0.9, 2, 4, and 6 wt.% of Cu) have been synthesized via sol-gel method. The photocatalysts were extensively characterized by means of inductively coupled plasma optical emission spectrometry (ICP-OES), N₂ physisorption (BET), XRD, UV-vis DRS, FT-IR, Raman spectroscopy, TEM-EDX, and photoelectrochemical measurements. The as-prepared photocatalysts contain anatase as a major crystalline phase with a crystallite size around 13 nm. By increasing the amount of Cu, specific surface area and band gap energy decreased in addition to the formation of large agglomeration of CuO. Results revealed that the photocatalytic reduction of CO₂ decreased in the presence of Cu/TiO₂ in comparison to pure TiO₂, which might be associated to the formation of CuO phase acting as a recombination center of generated electron-hole pair. Decreasing of photoactivity can also be connected with a very low position of conduction band of photocatalysts with high Cu content, which makes H₂ production necessary for CO₂ reduction more difficult.