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.

The potential for climatic factors as well as soil–plant–climate interactions to change as a result of rising levels of atmospheric CO₂ concentration is an issue of increasing international environmental concern. Agricultural and forest practices and managements may be important contributors to mitigating elevated atmospheric CO₂ concentrations. A computer model was developed using the Structural Thinking and Experiential Learning Laboratory with Animation (STELLA) software for soil CO₂ emissions from a short-rotation woody crop as affected by soil water and temperature regimes, root and microbial respiration, and surficial processes such as rainfall, irrigation, and evapotranspiration. The resulting model was validated with good agreement between the model predictions and the experimental measurements prior to its applications. Two scenarios were then chosen to estimate both diurnal and annual soil CO₂ emissions from a 1-ha mature cottonwood plantation as affected by soil temperature, soil (i.e., root and microbial) respiration, and irrigation. The simulation resulted in typical diurnal soil respiration and CO₂ emission patterns, with increases from morning to early afternoon and decreases from early afternoon to midnight. This pattern was driven by diurnal soil temperature variations, indicating that soil temperature was the main influence on soil respiration and CO₂ efflux into the atmosphere. Our simulations further revealed that the average seasonal soil respiration rate in summer was 1.6 times larger than in winter, whereas the average seasonal CO₂ emission rate in summer was 1.77 times larger than in winter. Characteristic annual variation patterns for soil respiration and CO₂ emission also were modeled, with both increasing from January 1 through June 30 followed by steady declines from September 1 through December 31. These results suggest that the STELLA model developed is a useful tool for estimating soil CO₂ emission from a short-rotation woody crop plantation.

Vapor phase mass transfer is an important interphase transport process that dominates the overall transport phenomena in liquid–gas system in porous media. Volatilization of nonaqueous phase liquids (NAPLs) in porous media is such system that takes place during the remediation of volatile organic compound-contaminated soil using soil vapor extraction. Usually, interphase mass transfer coefficient is lumped together with the air–liquid interfacial area because of the inaccessibility to quantify this parameter due to the heterogeneous nature of the pore structure of the media and the morphology of the fluid distribution. In this paper, the air–liquid interfacial area is quantified using a simple method derived from pressure–saturation relationship in three glass bead media. A series of one-dimensional NAPL volatilization experiments were carried out in a horizontal column for the same porous media by using toluene as the single contaminant. Experiments were conducted for NAPL saturation range of 13.8 ~ 71 % and pore gas velocities of 0.1 ~ 2 cm/s, and lumped mass transfer coefficients were evaluated. Actual vapor phase mass transfer coefficients were calculated using corresponding air–liquid interfacial area for a specific NAPL saturation and characterized in dimensionless form for all porous media. Results revealed that the vapor phase mass transfer increases with pore gas velocities and grain sizes but decreases with NAPL saturation.

Uptake, bioaccumulation, and assimilation of ferricyanide by three different species of willows was investigated. Intact prerooted weeping willows (Salix babylonica L.), Hankow willows (Salix matsudana Koidz), and hybrid willows (S. matsudana Koidz × alba L.) were grown hydroponically and treated with ferricyanide at 25.0 ± 0.5 °C for 144 h. Willows without leaves were also investigated as a treatment to quantify effect of transpiration on transport and assimilation of ferricyanide. Dissociation of ferricyanide to free cyanide in solution in absence of light was negligible. Phytotransport of ferricyanide was apparent. The phytoremoval rate of ferricyanide obtained varied with willow species (p < 0.05). Remarkable decreases in the removal rate were detected with the trees without leaves compared with the intact trees (p < 0.01). Due to small amounts of the applied ferricyanide recovered in plant materials, ferricyanide removed from the hydroponic solution was largely assimilated by plants. Transpiration stream concentration factor (TSCF) was also estimated using the content of iron (Fe). These information suggests that phytodegradation is a major process involved in botanical assimilation of ferricyanide through an undefined degradation pathway.