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.

To date, numerous studies have employed single type nitrogen (N) addition methods in reporting influences of N deposition on soil extracellular enzymatic activities (EEA) during litter decomposition in forest ecosystems. As natural atmospheric N deposition is a set of complex compounds including inorganic N and organic N, it is essential for investigating responses of soil EEA to various mixed N fertilization. In a subtropical forest stand in Zijin Mountain, East China, various N fertilizers with different inorganic N and organic N ratios were added to soils monthly from 2008 to 2009. Samples were harvested from N fertilized and control plots every 4 months. Subsequently, six EEA were assayed. A laboratory experiment was also conducted simultaneously. Both field and laboratory experiments showed that various mixed N fertilizations revealed different influences on soil EEA. Acceleration of most soil EEA by mixed N fertilization was greater than that of single N fertilization. The majority of soil extracellular enzymes exhibited the highest activities under mixed N fertilization, with the ratio of inorganic N to organic N at 3:7. These results suggested that N type and ratio of inorganic N and organic N were important factors controlling soil EEA, and the 3:7 ratio of inorganic N and organic N may be the optimum for soil EEA.

The Gorka pit lake was formed in an inactive Jurassic limestone quarry after cessation of open-pit dewatering. The main problem of the water quality in this area is linked to a large volume of extremely alkaline leachate disposed in the flooded quarry. The lake is meromictic due to a large density contrast between shallow and deep water layers. Water in the lake is of the Na-CO₃-OH type, pH is in the range from 11.5 to 13.3, and there are high concentrations of sulfate and several toxic elements (Al, As, Cr, Mo, P, and V). The chemical composition of the extremely alkaline leachate was formed as a result of the groundwater interaction with the industrial red mud wastes containing 5-10 wt.% of sodium carbonate. There is a trend of increasing concentrations and pH values with depth, mainly due to the in-gassing of atmospheric CO₂ into the surface layer and due to density stratification in the water column. Similar stratification is observed in groundwater wells around the lake. High dissolved concentrations of oxyanionic contaminants such as As, Cr, and V are caused by their high mobility and desorption under extremely alkaline conditions. In spite of reducing conditions at the bottom of the lake, caused by high concentrations of dumped organic matter, sulfate behaves conservatively because sulfate reducing bacteria do not survive in this pH range.

The main goals of this study were (1) to standardize a simple and reliable embryotoxicity test for environmental contaminants and (2) to evaluate the presence and possible protective role of the multidrug resistance-associated (MRP) protein-mediated multixenobiotic defense in two Mediterranean sea urchin species, Paracentrotus lividus and Arbacia lixula. Toxic end-point used was the success of the first cell division in sea urchin embryos. Embryotoxicities of three environmentally relevant contaminants: mercuric chloride (HgCl2, 0.05–6 μM), trybutiltin (TBT, 2.5–500 nM), and oxybenzone (OXI, 0.1–100 μM); as well as seawater samples collected from the polluted and unpolluted locations, were determined and compared. A. lixula embryos were more sensitive to all three toxic compounds, and both P. lividus and A. lixula embryos were highly sensitive to TBT at nanomolar concentrations (EC50 49 ± 5 and 36.8 ± 3 nM, respectively). Inhibition of MRP protein by specific inhibitor MK571 caused significant increase in embryotoxic potency of HgCl2 (EC50 0.697 ± 0.03 and 0.245 ± 0.04 μM, respectively), TBT (EC50 24 ± 3 and 7.4 ± 1 nM, respectively) and polluted seawater sample, but not of OXI or unpolluted, natural seawater. Therefore, our results demonstrated for the first time the protective relevance of MRP proteins in early development of these two Mediterranean sea urchin species. Finally, the embryotoxicity protocol described in this study represents a simple and rapid bioassay for determination of environmentally relevant seawater contamination.

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).

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.

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.