The sequential elution technique (SET) is used to determine the distribution of elements in the different cell fractions of mosses. The extracellular extractants most commonly used in this technique are NiCl2 and EDTA, although there are certain disadvantages associated with their use. In order to avoid such problems, we searched for new extractants that displace extracellularly bound metals, either because they are present at high concentrations (Ca) or because they have a high affinity for cation exchange sites (Hg and Au). The compounds HCl, NaCl, and CaCl2 were tested as extractants of the former type, as possible alternatives for the determination of extracellular metals in the moss Pseudoscleropodium purum. Calcium chloride was finally chosen as is it potentially the most successful in terms of binding to the cation exchange sites without altering the membrane permeability. The concentration chosen was 160 mM, as this yielded maximum displacement of Zn without membrane alterations. An experiment was then carried out to test the efficiency of Ca in extracting extracellular Zn, under laboratory and field conditions. In addition, Hg and Au were tested, at different concentrations, as extractants with high affinity for cation exchange sites, as neither of these elements has previously been used in the SET, and both display electronic characteristics that suggest their potential usefulness in displacing other cations from cation exchange sites. The results obtained show that extraction of extracellularly bound metal by high concentrations of Ca should be ruled out, as total extraction of Zn was not achieved. Both Hg and Au produced membrane alterations at low concentrations and moreover, neither was more efficient at extracting Zn than the reference extractant (20 mM NiCl2).

We present here the effects of ambient ozone (O₃)-induced decline in carbon availability, accelerated foliar senescence, and a decrease in aboveground biomass accumulation in the Aleppo pine (Pinus halepensis Mill.). Aleppo pine seedlings were continuously exposed in open-top chambers for 39 months to three different types of O₃ treatments, which are as follows: charcoal-filtered air, nonfiltered air (NFA), and nonfiltered air supplemented with 40 ppb O₃ (NFA+). Stable carbon isotope discrimination (Δ) and derived time-integrated c i/c a ratios were reduced after an accumulated ozone exposure over a threshold of 40 ppb (AOT40) value from April to September of around 20,000 ppb·h. An AOT40 of above 67,000 ppb·h induced reductions in ribulose-1,5-biphosphate carboxylase/oxygenase activity, aboveground C and needle N and K concentrations, the C/N ratio, Ca concentrations in twigs under 3 mm, and the aerial biomass, as well as increases in needle P concentrations and phosphoenolpyruvate carboxylase (PEPC) activity and the N and K concentrations in twigs under 3 mm. Macronutrients losses, the limitations placed on carbon uptake, and increases in catabolic processes may be the causes of carbon gain diminution in leaves which was reflected as a reduction in aboveground biomass at tree level. Stimulation of PEPC activity, the consequent decreased Δ, and compensation processes in nutrient distribution may increase O₃ tolerance and might be interpreted as part of Aleppo pine acclimation response to O₃.

The degradation of diesel and phenanthrene in waste water was studied in a column combining a submerged trickling-flow with a fixed-film at a determined biofilm thickness with recirculation. Degradation efficiencies were found to be high with the production of a biofilm thickness of 789 μm structured in a package material with proper adsorption and physicochemical properties necessary to reach a stable state condition for the degradation of recalcitrant components in 78% at a retention time of 3 h. Improved degradation rates were reached with a biofilm built from an adapted inoculum that showed the presence of Pseudomonas sp., Klebsiella sp. Enterobacter in a concentration of 6.45 × 109 CFU mL−1. Moreover, the biodegradation rate of the inoculumn was quantified. The diesel kinetic experimental data were well described by Gompertz model which provides a specific grow rate (Kb) of 0.76 ±â€‰0.36 h−1 and a correlation of R 2 = 0.93. The integral approach study of the variables of a complex degradation process lead to improve the complete operation of the reactor in comparison with other more specific component-based approaches.

Mechanism of zinc iron removal by zero-valent iron was discussed through zinc removal responses to several operational conditions of a packed column reactor with zero-valent iron powder. The adsorption isotherm observed implied that a kind of chemisorption was responsible for zinc removal. Zinc removal by zero-valent iron was enhanced by dissolved oxygen and ferric ion addition. However, it was deteriorated under acidic pH. In addition, zinc adsorbed on zero-valent iron was eluted by a reducing agent such as citric acid, whereas the zinc was not eluted by diluted sulfuric acid. Consequently, the zinc removal mechanism by zero-valent iron was inferred to be as follows: Zero-valent iron was firstly corroded and oxidized into ferric ion by dissolved oxygen. The ferric ion was precipitated as iron hydroxide onto the surface of the zero-valent iron powder. Zinc ion was adsorbed on and/or coprecipitated with the iron hydroxide. The iron hydroxide was finally oxidized and transformed into iron oxides.

Fly ash is one of the residues produced during combustion of coal, and its disposal is a major environmental concern throughout coal-based power-generated counties. Deficiencies of essential nutrients, low soil microbial activity, and high-soluble salt concentrations of trace elements are some of the concerns for reclamation of fly ash ponds. The effect of fly-ash-adapted arbuscular mycorrhizal (AM) fungi and phosphate solubilizing fungus Aspergillus tubingensis was studied on the growth, nutrient, and metal uptake of bamboo (Dendrocalamus strictus) plants grown in fly ash. Co-inoculation of these fungi significantly increased the P (150%), K (67%), Ca (106%), and Mg (180%) in shoot tissues compared control plants. The Al and Fe content were significantly reduced (50% and 60%, respectively) due to the presence of AM fungi and A. tubingensis. The physicochemical and biochemical properties of fly ash were improved compared to those of individual inoculation and control. The results showed that combination of AM fungi and A. tubingensis elicited a synergetic effect by increasing plant growth and uptake of nutrients with reducing metal translocation.

We report the isolation of a new bacterium species (named as DN-06) that degrades pyridine, a model compound containing both carbon and nitrogen, from the aerobic activated sludge in a coking wastewater treatment plant. DN-06 was identified as Achromobacter sp. using 16S rDNA sequence analysis. In batch culture, more than 95% of pyridine (500 mg/L) was degraded within 18 h by DN-06 grown at 35°C and pH 8 with agitation at 170 rpm. Degradation experiments of pyridine at different initial concentrations (50–4,300 mg/L) revealed that pyridine was an inhibitory substrate, and that neither yield coefficient Y nor endogenous decay coefficient K d was a constant. The values of Y and K d were 0.55–0.74 and 0.0032–0.0057 h−1, respectively. Five kinetic models (Haldane, Yano, Aiba, Webb, and Monod) were fitted to the experimental growth kinetic data. Models of Haldane and Yano (correlation coefficient R 2 = 0.929) were the most suitable models. For Haldane kinetic model, the values of μ max, K s, and K i were 0.161 h−1, 142.6 mg/L, and 4234.8 mg/L, respectively. The large values of Y and K i indicated that DN-06 had good tolerance against high pyridine concentrations. These results indicated possible future applications of Achromobacter sp. DN-06 in removing pyridine from industrial wastewaters, as well as in destroying pyridine in concentrated solutions during further treatment of trial water coupling with adsorption technology.

We investigated sediments from 23 lakes situated in northeastern Poland and analyzed them for major constituents and selected heavy metals. Short sediment cores were collected from the deepest parts of the lakes, and subsequently, a surface layer (0–2 cm) and reference layer (50–52 cm) were sampled from each. In the collected samples, the content of the major constituents (organic matter, carbonates, and minerogenic material) and chosen heavy metals (Cd, Cu, Ni, Pb, and Zn) was analyzed. In the reference layer, representing natural metal content, we identified quite a substantial diversity among lakes, making it difficult to pinpoint one geochemical background value for the whole region. A multivariate analysis of the interrelationships among elements and a comparison of the median values revealed no statistically significant differences between surface and reference levels. The ratio of the mean content in the surface and reference sediments ranged from 0.9 to 1.6, indicating the lack of or only slight anthropogenic pollution in surface sediments. From a spatial perspective, higher metal contents were observed in the eastern part of the study area, but this trend manifested in both surface and reference sediments. Thus, the inference is that the recently accumulated sediments are characterized by a content that is representative of the natural geochemical background for the selected metals.

In the last 10 years, the number of field applications of zero-valent iron differing from permeable reactive barrier has grown rapidly and at present are 112. This study analyzes and compares such field applications. By using statistical analysis, especially ANOVA and principal component analysis, this study shows that chlorinated solvent contamination can be treated efficiently by using zero-valent iron material singly or associated with other technologies. In the analyzed sample of case studies, the association with microbial dechlorination increased significantly the performances of nanoscale iron. This is likely due to the synergistic effect between the two processes. Millimetric iron was always used in association with source zone containment; therefore, it is not possible to distinguish the contributions of the two techniques. The comparison also shows that catalyst addition seems to not dramatically improve treatment efficiency and that such improvement is not statistically significant. Finally, the injection technology is correlated to the type of iron and to the soil permeability.