One of the major obstacles to zerovalent iron nanoparticles (nZVI) application in soil and groundwater remediation is the limited transport, especially in low-permeability soils. In this study, direct current (constant potential of 5.0 V) was used to enhance polymer-coated nZVI mobility in different porous media, including a bed of glass beads and kaolin clay. The tests were conducted using a modified electrophoretic cell and with nZVI concentrations typical of field applications (4 g L-1). Experimental results indicate that the use of direct current can enhance the transport of the polymer-modified nanoparticles when compared with natural diffusion in low permeability or surface neutral porous medium. The applied electric field appeared to enhance the oxidation-reduction potential, creating a synergistic effect of nZVI usage with electrokinetics. Aggregation of the nanoparticles, observed near the injection point, remained unresolved. © 2013 Springer Science+Business Media Dordrecht.

We studied the isotopic composition of organic matter in the sediments of eight mountain lakes located in the Tatra Mountains (Western Carpathians, Poland). The sediments of the lakes were fine and course detritus gyttja, mud, and sand. The total organic carbon content varied from 0.5 to 53 %. The C/N ratio indicated that in-lake primary production is the major source of the organic matter in the lakes located above the treeline, whereas terrestrial plant fragments are the major organic compounds in the sediments of dystrophic forest lakes. We also found that a clear trend of isotopic curves toward lower values of δ ¹³C and δ ¹⁵N (both ~3 ‰) began in the 1960s. This trend is a sign of the deposition of greater amounts of NO ₓ from the combustion of fossil fuels, mainly by vehicle engines. The combustion of fossil fuels in electric plants and other factories had a smaller influence on the isotopic composition. This trend has been weaker since the 1990s. Animal and human wastes from pastures and tourism had a surprisingly minor effect on lake environments. These data are contrary to previous data regarding lake biota and suggest the high sensitivity of living organisms to organic pollution.

This paper investigates the electrochemical treatment of polychlorinated biphenyl (PCB) contaminated soils. The research was performed within a project co-funded by the European Regional Development Fund and for the experimental part; artificially contaminated soil with PCB was used. Two reactors of different sizes were used; the smaller designed in a Ph.D. research and the larger in a research project co-funded by the European Regional Development Fund. Specific voltage, current density, redox potential, time and pH values were considered throughout the tests. The initial PCB concentration in the test soil (3.571 mg/kgdw) exceeds the intervention threshold for sensitive use according to Romanian regulations (1 mg/kgdw). Three different tests were performed: within the first one (T1) the soil was polluted with insulating oil; within the other two tests (T2 and T3) the soil was contaminated with capacitor oil. The initial PCB concentrations within the three tests (as a sum of all PCB concentrations) were: 4.4461 mg/kgdw within T1, and 3.5710 mg/kgdw within both T2 and T3. The study showed that the electrochemical treatment could achieve up to 87 % remediation efficiency for PCB polluted soils. Therefore, this treatment is relevant and a potential solution for the remediation of PCB polluted soils.

Large quantities of pollutants such as phthalocyanine which are difficult to degrade by conventional techniques are discharged by the textile industry. Advanced oxidation processes have been shown to be capable of degrading organic compounds and removing colour from the industrial wastewater. In this research, the hydrogen peroxide (H2O2)/UV process under different operative variables has been checked using a photoreactor lab plant to analyse its behaviour in the removal of colour and chemical oxygen demand of synthetic textile wastewater with a pigment named phthalo blue 36:3 (C.I. PB15:3). Different pH and H2O2 concentrations were tested to find the better conditions for the UV/H2O2 process suitable for this kind of pollution; this was carried out as an initial study of the operative variables for the scale-up of this technology. The research has shown that with pH 7 and 5 g/L of H2O2, this process can get an organic matter removal higher than 89 % and a colour removal near 70 %. Different kinetic models of organic matter removal have been checked to analyse and predict the influence of time on the process to model similar conditions of pollution. The high correlation between empirical and theoretical data model was pseudofirst order (R 2 = 0.989 ± 0.007). © 2013 Springer Science+Business Media Dordrecht.

In this study, we have reported the synthesis of new amino-substituted p-tert-butylcalix[4]arene (3) and its application for the removal of two carcinogenic azo dyes, i.e., Chicago Sky Blue (CSB) and Tropaeolin 000 (TP) from aqueous environment. The newly synthesized calix–ligand 3 is characterized by FT-IR and ¹H NMR spectroscopy as well as elemental analysis. The extraction efficiency of newly calix–ligand 3 for CSB and TP dyes from aqueous media was evaluated through liquid–liquid extraction experiments. The newly synthesized calix–ligand 3 showed outstanding extraction percentage and maximum percent extraction, i.e., 97 and 96 % of CSB and TP dyes was achieved at pH 9, respectively. During the extraction process, effect of various parameters was monitored and found that extraction is highly dependent on pH and salinity. Moreover, cyclic structure, cavity size, functional groups of the calixarene derivative, hydrophobicity, and the ionic property of guest molecules also affect the extraction efficiency. The comparative data prop up calix–ligand 3 as an effective extractant for both CSB and TP dyes.

A novel porous biomorph-genetic composite of α-Fe₂O₃/Fe₃O₄/C (PBGC-Fe/C) with eucalyptus wood template was prepared, characterized and tested for its sorption capacity of As(V) from aqueous solution. The result indicated that the PBGC-Fe/C material retained the hierarchical porous structure of eucalyptus wood with three different types of pores (widths 70∼120, 4.1∼6.4 and 0.1∼1.3 μm) originating from vessels, fibres and pits of the wood, respectively. Its surface area was measured to be 59.2 m²/g. With increasing initial As(V) concentration from 5 to 100 mg/L, the amounts of As(V) sorbed on the pulverized PBGC-Fe/C sorbent (<0.149 mm) increased from 0.50 to 4.01 mg/g at 25 °C, from 0.50 to 4.83 mg/g at 35 °C and from 0.50 to 4.19 mg/g at 45 °C, and the corresponding removal rates decreased from 99.97 to 40.10 % at 25 °C, 99.95 to 48.40 % at 35 °C and 99.92 to 42.05 % at 45 °C. At the initial concentrations of 5, 10 and 50 mg/L, the sorption capacities for the unpulverized PBGC-Fe/C sorbent (>3 mm) were determined to be 0.50, 0.99 and 2.49 mg/g, respectively, which exhibited a similar average value to those of fine particles or nanoparticles of iron oxides. The sorption could well be described by the pseudo-second-order kinetic equation. The equilibrium data were found to follow Freundlich as well as Langmuir isotherms.

Atmospheric deposition occurs in a variety of forms and is crucial for the evaluation of nutrient budgets, critical loads, and pollution inputs across space and time. Atmospheric wet deposition is typically quantified by analyzing the chemistry of precipitation that is collected in some type of container with a lid that opens in response to precipitation. However, collectors can vary in shape as well as in the sensor that signals when precipitation is occurring. Here, we compare the collectors made by Aerochem Metrics and N-CON Systems Company Inc. The former has been widely used for several decades, while the latter is relatively new and has been used in a variety of configurations depending on the solute of interest. Event-based samples were collected from August 2007 to October 2008 and analyzed for nitrate, ammonium, sulfate, chloride, and dissolved organic carbon (DOC). A variety of approaches were used to assess the comparability of the two collectors. Regressions of concentration versus concentration from the two collectors were strong, and the slope did not differ from 1 for nitrate, ammonium, or sulfate. The median concentrations of nitrate, ammonium, and sulfate were, however, significantly higher in the N-CON collector, while there were no overall differences between collectors for chloride or DOC. Although we have observed some statistically significant differences between solute concentrations of samples collected from the two collectors, our mixed results suggest that these differences are relatively small.

Rhizoremediation is a complex type of green clean-up technology that involves both plants and the rhizosphere-associated microorganisms to decompose hazardous compounds. The success of the strategy strongly depends on plant tolerance towards the pollutant, as well as plant's interactions with the rhizospheric microbes. The microorganisms may be stimulated by the secreted root exudates, which results in an increased breakdown of contaminants in the rhizosphere. The main goal of this study was to establish a potential rhizoremediation combination for a diesel-polluted site. Inoculation of plant roots or seeds with indigenous rhizospheric populations is a common approach in the rhizoremediation. However, we introduced hydrocarbon-degrading consortia (M10, R3, and K52) that were previously isolated from crude oil-contaminated soil instead of indigenous microbes. Bioaugmentation with these petroleum degraders was applied to screen four high biomass crop species (Indian mustard, alfalfa, high erucic acid rapeseed, HEAR, and low erucic acid rapeseed, LEAR) for their tolerance towards diesel oil. At no pollution, a promoting effect of M10 bacteria could be observed on germination and root elongation of all plant species. Moreover, M10 consortiums increased the germination index at 6,000 mg diesel oil per kilogram dry soil in the case of Indian mustard, alfalfa, and HEAR. The latter species was found to increment its dry weight upon bioaugmentation with M10 bacteria and all diesel oil treatments (6,000 and 24,000 mg diesel oil per kilogram dry soil). The initial results indicate HEAR and the M10 bacterial consortium as a promising plant-microbe tandem for a long-term rhizoremediation process. © 2013 The Author(s).

Chlorpyrifos (O, O-diethyl-O-(3,5,6-trichloro-2-pyridyl) phosphorothioate) is a broad-spectrum organophosphate insecticide and acaricide, widely used in our country. Nowadays, it is the principal insecticide in the market employed for agricultural purposes. A number of studies tending to study the affinity of different pesticides with soil have been performed, but only a few refer to chlorpyrifos. Because of its intensive use, a wide range of terrestrial ecosystems may be contaminated with chlorpyrifos, and there is a need to evaluate its environmental behavior and effects. The aim of our work is to study the interaction and persistence of a commercial formulation of chlorpyrifos on an agricultural soil from Provincia de Buenos Aires, Argentina. In this case, recovery percentages increased with the increase of initial concentration of the pesticide until a concentration of about 25 ppm is reached, and then a decrease was observed. The half-time life was not affected by an increase in chlorpyrifos concentration.

As a polycyclic aromatic hydrocarbon (PAH), pyrene is one of hazardous persistent organic pollutants in the aquatic environment. The aim of this study was to investigate the influence of denitrifying conditions on pyrene degradation in a pure culture. With a strain isolated from petrol-contaminated river sediment, treatments of pyrene biodegradations were set up using various ratios of nitrate to nitrite (NO₃ ⁻/NO₂ ⁻). Results showed that various NO₃ ⁻/NO₂ ⁻ conditions significantly influenced the anaerobic pyrene degradation efficiency. Nitrite could induce the complete denitrification process so that NO₂ ⁻ acted as a key factor to promote high degradation efficiency. The low N treatment of NO₃ ⁻ and NO₂ ⁻ concentrations made the denitrifying-pyrene-degradation process more effective. Additionally, high C/N value stimulated high degradation rates. High concentrations of NO₃ ⁻ and NO₂ ⁻ as well as toxic intermediate product accumulation might inhibit the bacterial growth and biodegradation process. The information from this study should be useful to design bioremediation strategies of PAH.