A comparison of chromium abatement from irrigation water, by the use of two selected plant species, Phragmites australis and Helianthus annuus, planted in chromium-contaminated soil, was studied in the present work. The above plant species were irrigated, in a continuous mode, with 10 mg Crⱽᴵ/L contaminated tap water. More than 90 % of hexavalent chromium was reduced to trivalent chromium, from both plant species, as measured in the drainage water. Moreover, total chromium removal ranged from 54 % (Phragmites) to 70 % (Helianthus). After 90 days, the total chromium content of the contaminated soil dropped from 70 to 32 and 34 mg Cr/kgdᵣy ₛₒᵢₗ, for Helianthus and Phragmites, respectively. Helianthus accumulated higher amount of chromium in the roots (2,730 mg Cr/kgdᵣy ₜᵢₛₛᵤₑ) as compared to 1,800 mg Cr/kgdᵣy ₜᵢₛₛᵤₑ for Phragmites. Most of Crⱽᴵ was reduced to Crᴵᴵᴵ in all plant tissues, with Phragmites showing lower affinity for Crⱽᴵ reduction in the root tissues but higher chromium translocation potential from roots to stems, while Helianthus showed higher chromium translocation from roots to leaves. Toxicity effects, expressed as root growth rate inhibition, indicated that Phragmites were the most tolerant specie to chromium effects. Both plant species showed high potentialities to be used in phytoremediation installations for chromium removal.

This study aimed to evaluate the efficacy of using the byproduct of Moringa oleifera Lam. seeds as an adsorbent for removal of cadmium (Cd) from contaminated water. The material characterization was performed by scanning electron microscopy, infrared spectroscopy, and point of zero charge. The effects of the adsorbent mass, solution pH, contact time, and temperature were evaluated. In the preliminary studies, the mass of adsorbent (200–1200 mg) and pH conditions (5.0, 6.0, and 7.0) were varied. The time studies were performed at 20–180 min and the temperature studies at the range of 25–65 °C. The optimal conditions of adsorption obtained were 400 mg of adsorbent mass, 7.0 pH, and 160 min contact time with the adsorbent. The isotherms of adsorption were linearized according to Langmuir, Freundlich, and Dubinin–Radushkevich (D-R) models. The results showed better fit by the Freundlich and D-R models for Cd adsorption, describing a multilayer adsorption and, according to the value of the sorption energy (E), it has chemical nature. The maximum capacity of adsorption (Q ₘ) obtained was 7.864 mg g⁻¹. For a comparative study, the activated carbon (P.A.) was used applying the same optimal conditions used in the adsorption isotherms and desorption process for the biosorbent, obtaining a Q ₘ as 32.884 mg g⁻¹. The average desorption percentage showed that adsorbents have strong interaction with the metal. Based on these results, it was concluded that the biosorbent was effective in remediation of solutions containing Cd and thus the use of this alternative material is a viable option, since it has low cost and it is a byproduct which has not undergone previous treatment.

The removal of lead (II) and iron (III) from aqueous solutions using empty fruit bunch (EFB), oil palm leaves (OPL), oil palm frond (OPF), and oil palm bark (OPB) as biosorbents was investigated. The biosorbents were characterized through scanning electron microscopy, Brunauer–Emmett–Teller analysis, and Fourier transform infrared spectroscopy. Variables such as pH (2–12), biosorbent particle size (200–1,400 μm), adsorbent dosage (0.25–1.75 g/l), and agitation time (5–80 min) were investigated. The suitable pH range, particle size, adsorbent dosage, and agitation time for the removal of both metals were 5 to 6, 200 μm, 1 g/l, and 40 min, respectively. Under optimum conditions, OPB showed the highest adsorption efficiency of 80 % and 78 % for lead and iron, respectively. The adsorption equilibrium data were fitted to three adsorption isotherm models. The Langmuir isotherm showed the best result for both metals. The kinetics of the biosorption process was analyzed using pseudo-first-order and pseudo-second-order models. The latter showed a better fit for both metals. OPB biomass introduced the lowest chemical oxygen demand into the treated solution, with an average amount of 32.9 mg/l.

Wild birds have been shown to be significant sources of numerous types of pathogens that are relevant to humans and agriculture. The presence of large numbers of migratory birds in such a sensitive and important ecosystem as the Platte River in central Nebraska, USA, could potentially serve a significant source of bird-derived pathogens in the water/sediment and riverine environment. In 2009 and 2010, a study was completed to investigate the potential water-quality impacts of Sandhill Cranes and Snow Geese on the microbial water quality of the central Platte River during their spring migration period. Fecal material, river-bottom sediment, and water samples were collected from January through May of each year during the spring migration season of Sandhill Cranes in the Central Flyway of North America. Results indicate that several types of fecal indicator bacteria and from a range of viral, protozoan, and bacterial pathogens, Campylobacter jejuni were present in Sandhill Crane excreta, and at significantly higher frequency and densities in water and sediments when the Sandhill Cranes were present, particularly during evening roosts within the Platte River environment. Therefore, further investigation of the health significance of avian pathogens is warranted for the Platte River in Central Nebraska during migration of Sandhill Cranes and other waterfowl.

Alpine ecosystems, representing a large proportion of the land area in Europe, are under pressure from changes in climate and land-use. This may also impact the quality of drainage waters. Here, we assess effects of plant communities (snowbed, dwarf shrub heath, and tall herb meadow) on concentrations of dissolved organic carbon and nitrogen (DOC and DON), ammonium (NH₄-N), nitrate (NO₃-N), and phosphorus (tot-P and PO₄-P) in locally derived seepage water in a non-fertilized sub-alpine area of southern Norway. In addition, we investigated effects of two density levels of sheep (no sheep and 80 sheep km⁻²) on infiltration capacity, pore size distribution and concentrations of nutrients and bacteria in surface runoff. Concentrations of NO₃-N (<0.02–0.03 mg l⁻¹) and NH₄-N (<0.02–0.03 mg l⁻¹) were low in seepage waters with no significant differences associated with plant community. Also, concentrations of DOC and DON were low, in particular in snowbeds, probably due to low productivity and small soil carbon pools. Infiltration rates, which were significantly smaller in snowbeds than in tall herb meadow, were further reduced by grazing. In turn, this caused increased runoff of coliform bacteria, whereas no effect of grazing on NH₄-N, NO₃-N and PO₄-P was observed. Grazing may significantly alter biological water quality but is not likely to affect the productivity of surface waters in non-fertilized alpine areas.

The evaluation of the contribution of natural sources to PM₁₀ and PM₂.₅ concentrations is a priority especially for the countries of European south strongly influenced by Saharan dust transport events. Daily PM₂.₅ concentrations and composition were monitored at an urban site at 14 m above ground level, at the National Technical University of Athens campus from February to December 2010. The typical dust constituents Si, Al, Fe, K, Ca, Mg, and Ti were determined by wavelength dispersive X-ray fluorescence spectrometry (WDXRF). Sulfur, a tracer of anthropogenic origin and major constituent of PM₂.₅, was determined by both WDXRF and ionic chromatography. The contribution of dust and sulfates in PM₂.₅ was calculated from the analytical determinations. An annual mean of 20 μg/m³ was calculated from the mean daily PM₂.₅ concentrations data. Twenty-two per cent of daily concentrations of PM₂.₅ reached or exceeded the EU annual target concentration of 25 μg/m³. The exceedances occurred during 13 short periods of 1–4 days. Back-trajectory analysis was performed for these periods in order to identify the air masses origin. From these periods, ten periods were associated to Saharan dust transport events. The most intense dust transport event occurred between February 17th and 20th and was responsible for the highest recorded PM₂.₅ concentration of 100 μg/m³ where the dust contribution in PM₂.₅ reached 96 %. The other dust transport events were less intense and corresponded to less pronounced enhancements of PM₂.₅ concentrations, and their contribution ranged from 15 to 39 % in PM₂.₅ concentrations. Air masses originated from northwest Africa while the influence of central Sahara was quite smaller.

Some Pseudomonas fluorescens strains, consistently isolated from the rhizosphere of wild plants grown in a soil that was highly polluted with illegal waste of smelter residues, were utilised for Mirabilis jalapa seed bioinoculation to verify their effects on seed germination and on promoting a higher heavy metal accumulation in the plant rhizosphere and/or uptake in the leaves. The high content of heavy metals in the soil induced a decrease in either the leaf dry weight or photosynthetic pigment concentration during all vegetative phase of M. jalapa. Bioinoculation with P. fluorescens strains significantly increased the germination of seeds and the root length in the contaminated soil. In some bacterial strain/seed combination, bioinoculation significantly increased the accumulation of heavy metals in M. jalapa rhizosphere. For Cd, the concentration of this metal in the rhizospheres of bioinoculated plants ranged from 270 to 910 μg g-1 of dry weight compared with 200 μg g-1 of dry weight for the non-coated plants. Two P. fluorescens strains, AA27 and MO49, which were isolated from Artemisia annua and Melilotus officinalis, respectively, induced a significantly higher rhizosphere availability also for Cr, Cu, Ni and Zn. However, despite the relevant accumulation of the heavy metals in the plant rhizosphere, generally the metal uptake into the leaves was rather low. Both analysis of variance and principal component analysis confirmed this finding. However, one P. fluorescens strain, CD1, which was isolated from the multi-metal accumulator Cynodon dactylon, significantly promoted the M. jalapa leaf uptake for Cr, Cu and Zn. The plant metal uptake assessment, confirmed the per se capability of M. jalapa to effectively uptake Cd (30 %) and Cu (12.72 %) from the rhizosphere to the leaves, whereas the uptake for the other metals was low: Ni (2.66 %), Zn (2.46 %), Cr (1.75 %), Pb (0.73 %). © 2013 Springer Science+Business Media Dordrecht.

Kriging interpolation technique is adapted to create the mapping of surface ozone seasonality and trends across Europe during 1997–2006, based on European Monitoring and Evaluation Programme ground measurements. The climatology, the annual and seasonal trends and the altitude above sea level (asl) dependence were studied as well as the relation with the North Atlantic Oscillation (NAO). The mean seasonal cycle amplitude and seasonal maximum display an increasing gradient from northwest to southeast, with high levels in Austria and eastern Mediterranean. Significantly close to 0 positive trends appear in UK, Slovakia, southern Scandinavia and Austria in winter and autumn. In Northern Hemisphere winter (December–February), about 40 % of near-surface ozone variability in the western edge of Europe may be attributed to circulation changes and ozone precursors’ transport related to NAO.

An experimental design methodology was applied for response surface modeling and optimization of diethyl phthalate (DEP) removal from synthetic wastewater by continuous-flow ozonation. The five independent variables considered were the initial concentration of DEP, initial solution pH, liquid flow rate, gas flow rate, and ozone concentration in the inlet gas. Using the Box–Behnken design, two quadratic models were developed as a functional relationship between respectively DEP removal efficiency and ozone mass transfer and the independent variables considered. It was found that all the factors considered have a significant effect on the removal efficiency response, except for the gas flow rate which did not influence DEP removal in the ranges considered. The results show that the ozonation efficiency can be predicted and are in very good agreement with the experimental data. Optimal conditions for two different sets of constraints were determined.

There are significant concerns about the impact of heavy metal contamination in soils as a consequence of urbanisation and industrialisation in developing countries. Routine chemical analysis of soils is used to measure the total concentration of metals from point source or diffuse activities, but this fails to put in context the bioavailability of the analyte or the potential toxicity of multiple contaminants. Bacterial biosensors provide a useful tool for assessing the toxicity of the bioavailable fraction of heavy metals in soils and for complementing chemical analysis. There are few examples of genuine environmental applications of biosensors for pollutant diagnosis. This study applied constitutively marked biosensors (which were comprehensively characterised) to soils collected from across Northern China (60,000 km²). The biosensors were responsive to soils impacted by As, Cd, Cr, Cu, Hg, Pb, and Zn when compared to ‘uncontaminated controls’. The response of the biosensor correlated with individual (or groups of) metals related to their concentration and source. The geo-accumulation index (I gₑₒ) assisted in explaining the biosensor response. The constitutively marked biosensors offered a focussed understanding of analyte bioavailability and placed in a relevant context the elemental analysis. When matrix-matched control samples can be collected, then such a biosensor procedure (as adopted here) is applicable to contrasting soils exposed to a wide range of contaminants. Biosensor applications complemented routine soil chemical analysis for this regional-scale study.