The objective of this study is to investigate the potential impact of future climate change on ozone air quality in Europe. To provide a full assessment, simulations with the global chemical transport model GEOS-CHEM driven by the NASA Goddard Institute for Space Studies general circulation model (NASA/GISS GCM) are conducted. To isolate the effects from changes in climate and anthropogenic emissions four types of simulations are performed: (1) present-day climate and emissions (2) future climate following the IPCC Special Report on Emission Scenarios (SRES) A1B scenario and present-day anthropogenic emissions of ozone precursors (3) present-day climate and future emissions and (4) future climate and future emissions. Results indicate that climate change impact on its own leads to an increase of less than 3 ppb in western and central Europe whereas decreases are evident for the rest of the areas with the highest (about 2.5 ppb) in southeastern Europe (Italy, Greece). Increases are attributed to the increases of isoprene biogenic emissions due to increasing temperatures whereas decreases are associated with the increase of water vapor over sea which tends to decrease the lifetime of ozone as well as the increased wind speeds in the 2050 climate. When future emissions are implemented in the future climate simulations, the greatest increases are seen in the southwest and southeast Mediterranean (about 16 ppb) due to the increased isoprene biogenic emissions under higher levels of NO ₓ in the model. Decreases up to 2 ppb of ozone are shown for France, Switzerland, Northern Italy and northern Europe.

The use of aqueous suspension of nanoparticles of titanium dioxide for photocatalytic removal of pollutants is not suitable for industrial applications due to the inconvenient and expensive separation of nanoparticles of titanium dioxide for reuse. The nanosized titanium dioxide needs to be immobilized on the support for improving the efficiency and economics of the photocatalytic process. In the present paper, nanoparticles of titanium dioxide have been immobilized on the surface of the support using three different techniques. The immobilized films of titanium dioxide have been characterized using X-ray diffraction and scanning electron microscopy to notice any change in the phase composition and photocatalytic properties of the titanium dioxide after immobilization on the support. A photocatalytic test has been performed under similar reaction conditions to compare the photocatalytic performance of the films of immobilized titanium dioxide prepared using different techniques.

A post-harvest experiment was conducted further to our previous greenhouse pot study on upland kangkong (Ipomoea aquatica Forsk.) and Alfred stonecrop (Sedum alfredii Hance) intercropping system in Cd-contaminated soil inoculated with arbuscular mycorrhizal (AM) fungi. Previously, four treatments were established in the intercropping experiment, including monoculture of kangkong (control), intercropping with stonecrop (IS), and IS plus inoculation with Glomus caledonium (IS+Gc) or Glomus versiforme (IS+Gv). Both kangkong and stonecrop plants were harvested after growing for 8 weeks. Then, the tested soils were reclaimed for growing post-harvest kangkong for 6 weeks. In the post-harvest experiment, there were no significant differences between the IS and control treatments, except for a significantly decreased (p<0.05) soil available P concentration with IS treatment. Compared with IS, both IS+Gc and IS+Gv significantly decreased (p<0.05) soil DTPA-extractable (phytoavailable) Cd concentrations, but not total Cd, by elevating soil pH, causing significantly lower (p<0.05) Cd concentrations in both the root and shoot of kangkong. In addition, both Gc and Gv significantly increased (p<0.05) soil acid phosphatase activities and available P concentrations and hence resulted in significantly higher (p<0.05) plant P acquisitions. However, only Gv significantly increased (p<0.05) kangkong yield, while Gc only significantly elevated (p<0.05) the shoot P concentration. It suggested that AM fungi have played key roles in Cd stabilization and P mobilization in the intercropping system, and such positive responses seemed to be sustainable and valuable in post-harvest soils.

Field experiments were conducted in the 2008–2009 soybean and winter wheat-growing seasons to assess soil respiration (SR) and nitrous oxide (N₂O) emission as affected by enhanced UV-B radiation and straw incorporation. The SR rate was measured using a soil CO₂ flux system; the N₂O flux was measured using a static chamber–gas chromatograph technique. The results showed that in the soybean and winter wheat-growing seasons, enhanced UV-B radiation significantly decreased the SR rates and that straw incorporation increased the SR rates compared to the control treatment. The combined treatment of UV-B and straw incorporation had no obvious influence on the SR rates. Enhanced UV-B radiation, straw incorporation, and the combination treatment increased the temperature sensitivity of SR in the soybean-growing season. The study also showed that N₂O emissions were reduced by enhanced UV-B radiation and that straw incorporation had no significant effects on the mean N₂O emission fluxes in the soybean and winter wheat-growing seasons. Our findings suggest that enhanced UV-B radiation may lead to a decrease in SR and in N₂O emissions, straw incorporation may increase SR, and the combined treatment may have no significant influence on SR and N₂O emissions from soybean–winter wheat rotation systems.

Mining creates large amounts of processed waste in the form of mine tailings. Sulfide mine tailings are of particular concern due to the biotic and abiotic oxidation of sulfide minerals that release acidity and metals into the environment. Revegetation can be employed to mitigate the spread of tailings in the environment. Revegetation often involves ameliorating tailings with organic materials to promote plant growth and improve tailings physicochemical structure. We amended plots in the Central Manitoba Mine tailings pond with humic substances applied at rates up to 4 g C kg-1 through roto-tilling and seeded with Medicago sativa and Elymus trachycaulus in 2003 and 2004. The humic substances improved tailings fertility by increasing macro aggregation, organic carbon, and macronutrients but also resulted in a short-term increase in electrical conductivity levels. In the first growing season the humic amendment had little effect on plant yield, except in the 2003 experiment where the yield of E. trachycaulus decreased by 84 % with 4 g C kg-1 amendment. After 7 years, the addition of humic amendment resulted in a cover of over 38 % for M. sativa, compared to less than 2 % in control plots. In addition, non-seeded species cover increased with amendment rate in the 2003 experiment but not the 2004 experiment, most likely due to lower pH in the latter. Our results suggest that short-term patterns of plant performance do not reflect longer-term performance or invasion by volunteer plant species. Our long-term data suggest that humic amendments can be effective in establishing plant invasion of mine tailings, although the effects vary depending on the pH of the tailings. © 2013 Springer Science+Business Media Dordrecht.

A low-cost microbial fuel cell (MFC) with a brush-shaped anode was constructed with low-cost materials and operated in a fed-batch mode using wastewater as a substrate. The operational performance of the MFC was evaluated considering the organic matter removal, coulombic efficiencies, and current and power densities. Its relative performance to cost was evaluated considering a MFC with platinum/carbon cathode. It was observed that the organic matter removal efficiency was up to 80 % and the coulombic efficiencies varied from 3.5 to 5.7 %. Maximum average voltages and power and current densities of 207 ± 30 mV, 9.2 ± 2.4 mW m-2, and 56.8 ± 14.9 mA m-2 were obtained, respectively. It was observed that the low-cost MFC produced higher power and current densities per dollar when compared to a MFC using platinum-catalyzed electrode. © 2013 Springer Science+Business Media Dordrecht.

A better understanding of the effect of anthropogenic pollution on the formation of toxic Microcystis blooms is particularly important in regions with large urban centres where rivers, lakes, and estuaries receive large quantities of contaminated domestic and industrial wastes. The response of the bloom-forming cyanobacteria Microcystis aeruginosa CALU 972 and CALU 973 from Russian Karelia to pollution was investigated. The contaminants caused compensatory-adaptive changes that led to the retention of cell viability in the cyanobacterial cells. The adaptation to metals and 1,2,4-triazole was realised due to photosystem changes and the enhanced production of organic compounds, such as proteins and exopolysaccharides. Nutrients caused a significant increase in biomass production by M. aeruginosa. The exposure of M. aeruginosa to nutrients and zinc stimulated growth and contributed to enhanced microcystin concentrations. Variants of microcystins responded differently to pollution. Contaminants had pronounced effects on microcystin RR levels but less effects on microcystin LR levels. Heavy metals, 1,2,4-triazole and nitrogen influenced microcystin concentrations by affecting both the growth of Microcystis and hepatotoxin release into the environment.

In the present paper, undoped and Ni-doped TiO2 sol-gel nanopowders have been prepared in order to establish the effect of Ni dopant on both material structure and photocatalytic properties. Two dopant concentrations of the transition metal (0.5 and 2 wt%) have been tested. The influence of both Ni dopant concentration and temperature of thermal treatment on the prepared powders has been followed using X-ray diffraction (XRD) method. A proper program has been used in order to establish the complete XRD structural characterization (lattice parameters, crystrallite sizes, internal strains). X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM) coupled with surface area electron diffraction (SAED) techniques have completed the structural and morphological characterization of the prepared materials. Magnetic measurements and photocatalytic activity determinations have also been performed. The correlation between the results of the mentioned methods has been accomplished, and the detailed interpretation of the relation between structure and photocatalytic activity measurements has been done. The concentration of 0.5 wt% of Ni dopant ensures a better photocatalytic activity, compared to that of 2 wt%. © 2013 Springer Science+Business Media Dordrecht.

Sepiolite reveals as a low-cost and efficient adsorbent for the adsorption of caffeine from aqueous solutions. The characterization of this material was carried out by N₂ adsorption–desorption at 77 K, Fourier transform infrared spectroscopy, thermogravimetric analysis, and electronic microscopy. Initially, batch adsorption experiments were developed in order to determine the equilibrium time and the adsorption isotherm of the system. Pseudo–first-order, Elovich equation, pseudo–second-order, and intra-particle diffusion models were applied to the experimental data to determine the adsorption kinetics. In continuous adsorption, the influence of several operation conditions (initial caffeine concentration, volumetric flow rate, and mass of adsorbent) on the shape of breakthrough curves and the mass transfer resistance was evaluated. Experimental data were fitted to the bed-depth service-time model bed-depth service-time (BDST). Through the calculation of the adsorption, parameters as breakthrough time or caffeine removal percentage can be concluded that the removal of this compound from aqueous solutions by adsorption in sepiolite beds is an alternative technique to the current methods, in order to eliminate this micropollutant.

A comparative long-term study of three subsurface horizontal-flow (HF) constructed wetlands (CW) treating winery wastewater was carried out. The water depth for HF1 was 0.3 m, while the depth for HF2 and HF3 was 0.6 m, respectively. Hydraulic loading rate ranged from 7 to 93 mm/d, while surface loading rates fell into the following ranges: 4–85 g COD/m²·d, 2–49 g BOD₅/m²·d and 0.5–6 g TSS/m²·d. The percentage of biological oxygen demand (BOD₅) removal clearly decreased when influent concentration increased, while surface removal rate increased and reached a maximum of approximately 8 g BOD₅/m²·d removed in the range of 10–20 g BOD₅/m²·d fed, depending on the CW depth. HF1 showed a worse performance than the other units, appearing to be more affected by high influent concentrations. Solids accumulation on gravel media, hydraulic conductivity and gas emissions were monitored over the 2.8 years of operation.