The concentrations of 15 priority PAHs were determined in the atmospheric gaseous and particulate phases from nine sites across Assiut City, Egypt. While naphthalene, acenaphthene, and fluorene were the most abundant in the gaseous phase with average concentrations of 377, 184, and 181 ng/m³, benzo[b]fluoranthene, chrysene, and benzo[g,h,i]perylene showed the highest levels in the particulate phase with average concentrations of 76, 6, and 52 ng/m³. The average total atmospheric concentration of target PAHs (1,590 ng/m³) indicates that Assiut is one of the highest PAH-contaminated areas in the world. Statistical analysis revealed a significant difference between the levels of PAHs in the atmosphere of urban and suburban sites (P = 0.029 and 0.043 for gaseous and particulate phases, respectively). Investigation of diagnostic PAH concentration ratios revealed vehicular combustion and traffic exhaust emissions as the major sources of PAHs with a higher contribution of gasoline rather than diesel vehicles in the sampled areas. Benzo[a]pyrene has the highest contribution (average = 32, 4 % for gaseous and particulate phases) to the total carcinogenic activity (TCA) of atmospheric PAHs. While particulate phase PAHs have higher contribution to the TCA, gaseous phase PAHs present at higher concentrations in the atmosphere are more capable of undergoing atmospheric reactions to form more toxic derivatives.

Bacillus megaterium F-8 exhibited an intracellular acetamide hydrolyzing activity (AHA) when cultivated in modified nutrient broth with 3 % tryptone, 1.5 % yeast extract, and 0.5 % sodium chloride, at pH 7.2, 45 °C for 24 h. Maximum AHA was recorded in the culture containing 0.1 M of sodium phosphate buffer, (pH 7.5) at 45 °C for 20 min with 0.2 % of acetonitrile and resting cells of B. megaterium F-8 equivalent to 0.2 ml culture broth. This activity was stable up to 55 °C and was completely inactivated at or above 60 °C. Maximum acyl transferase activity (ATA) was recorded in the reaction medium containing 0.1 M of potassium phosphate buffer, (pH 8.0) at 55 °C for 5 min with 0.85 mM of acetamide as acyl donor and hydroxylamine hydrochloride as acyl acceptor and resting cells of B. megaterium F-8 equivalent to 0.94 mg cells (dry weight basis). This activity was stable up to 60 °C and a rapid decline in enzyme activity was recorded above it. Under the optimized conditions, this organism hydrolyzed various nitriles and amides such as propionitrile, propionamide, caprolactam, acetamide, and acrylamide to corresponding acids. Acyl group transfer capability of this organism was used for the production of acetohydroxamic acid. ATA of B. megaterium F-8 showed broad substrate specificity such as for acetamide followed by propionamide, acrylamide, and lactamide. This amide hydrolyzing and amidotransferase activity of B. megaterium F-8 has potential applications in enzymatic synthesis of hydroxamic acids and bioremediation of nitriles and amides contaminated soil and water system.

In this study, the effect of silver nanoparticles and silver ions on Arabidopsis thaliana was investigated at physiological and molecular levels. The seedlings were grown in sublethal concentrations of silver nanoparticles and silver ions (0.2, 0.5, and 1 mg/L) in 1/4 Hoagland’s medium for 14 days under submerged hydroponic conditions. Significantly higher reduction in the total chlorophyll and increase in anthocyanin content were observed after exposure to 0.5 and 1 mg/L silver nanoparticles as compared to similar concentrations of silver ions. Lipid peroxidation increased significantly after exposure to 0.2, 0.5, and 1 mg/L of silver nanoparticles and 0.5 and 1 mg/L of silver ions. Qualitative analysis with dichloro-dihydro-fluorescein diacetate and rhodamine 123 fluorescence showed a dose-dependent increase in reactive oxygen species production and changes in mitochondrial membrane potential in the roots of seedlings exposed to different concentrations of silver nanoparticles. Real-time PCR analysis showed significant upregulation in the expression of sulfur assimilation, glutathione biosynthesis, glutathione S-transferase, and glutathione reductase genes upon exposure to silver nanoparticles as compared with silver ions. Overall, based on the physiological and molecular level responses, it was observed that exposure to silver nanoparticles exerted more toxic response than silver ions in A. thaliana.

Plants in the water level fluctuation zone of the Three Gorges Reservoir Region disappeared due to winter-flooding and prolonged inundation. Revegetation (plantation and natural recovery) have been promoted to restore and protect the riparian ecosystem in recent years. Revegetation may affect soil qualities and have broad important implications both for ecological services and soil recovery. In this study, we investigated soil properties including soil pH values, bulk density, soil organic matter (SOM), soil nutrients and heavy metals, soil microbial community structure, microbial biomass, and soil quality index under plantation and natural recovery in the Three Gorges Reservoir Region. Most soil properties showed significant temporal and spatial variations in both the plantation and natural recovery areas. Higher contents of SOM and NO₃-N were found in plantation area, while higher contents of soil pH values, bulk density, and total potassium were observed in the natural recovery area. However, there were no significant differences in plant richness and diversity and soil microbial community structure between the two restoration approaches. A soil quality index derived from SOM, bulk density, Zn, Cd, and Hg indicated that natural recovery areas with larger herbaceous coverage had more effective capacity for soil restoration.

Biofilters are widely adopted in Australia for stormwater treatment, but the reported removal of common faecal indicators (such as Escherichia coli (E. coli)) varies from net removal to net leaching. Currently, the underlying mechanisms that govern the faecal microbial removal in the biofilters are poorly understood. Therefore, it is important to study retention and subsequent survival of faecal microorganisms in the biofilters under different biofilter designs and operational characteristics. The current study investigates how E. coli survival is influenced by temperature, moisture content, sunlight exposure and presence of other microorganisms in filter media and top surface sediment. Soil samples were taken from two different biofilters to investigate E. coli survival under controlled laboratory conditions. Results revealed that the presence of other microorganisms and temperature are vital stressors which govern the survival of E. coli captured either in the top surface sediment or filter media, while sunlight exposure and moisture content are important for the survival of E. coli captured in the top surface sediment compared to that of the filter media. Moreover, increased survival was found in the filter media compared to the top sediment, and sand filter media was found be more hostile than loamy sand filter media towards E. coli survival. Results also suggest that the contribution from the tested environmental stressors on E. coli survival in biofilters will be greatly affected by the seasonality and may vary from one site to another.

A comparative study using native garlic peel and mercerized garlic peel as adsorbents for the removal of Pb²⁺has been proposed. Under the optimized pH, contact time, and adsorbent dosage, the adsorption capacity of garlic peel after mercerization was increased 2.1 times and up to 109.05 mg g⁻¹. The equilibrium sorption data for both garlic peels fitted well with Langmuir adsorption isotherm, and the adsorbent–adsorbate kinetics followed pseudo-second-order model. These both garlic peels were characterized by elemental analysis, Fourier transform infrared spectrometry (FT-IR), and scanning electron microscopy, and the results indicated that mercerized garlic peel offers more little pores acted as adsorption sites than native garlic peel and has lower polymerization and crystalline and more accessible functional hydroxyl groups, which resulted in higher adsorption capacity than native garlic peel. The FT-IR and X-ray photoelectron spectroscopy analyses of both garlic peels before and after loaded with Pb²⁺further illustrated that lead was adsorbed on the through chelation between Pb²⁺and O atom existed on the surface of garlic peels. These results described above showed that garlic peel after mercerization can be a more attractive adsorbent due to its faster sorption uptake and higher capacity.

Laboratory-scale batch, vertical, and horizontal column experiments were conducted to investigate the attenuative capacity of a fine-grained clayey soil of local origin in the surrounding of a steel plant wastewater discharge site in West Bengal, India, for removal of phenol. Linear, Langmuir, and Freundlich isotherm plots from batch experimental data revealed that Freundlich isotherm model was reasonably fitted (R² = 0.94). The breakthrough column experiments were also carried out with different soil bed heights (5, 10, and 15 cm) under uniform flow to study the hydraulic movements of phenol by evaluating time concentration flow behavior using bromide as a tracer. The horizontal migration test was also conducted in the laboratory using adsorptive phenol and nonreactive bromide tracer to explore the movement of solute in a horizontal distance. The hydrodynamic dispersion coefficients (D) in the vertical and horizontal directions in the soil were estimated using nonlinear least-square parameter optimization method in CXTFIT model. In addition, the equilibrium convection dispersion model in HYDRUS 1D was also examined to simulate the fate and transport of phenol in vertical and horizontal directions using Freundlich isotherm constants and estimated hydrodynamic parameters as input in the model. The model efficacy and validation were examined through statistical parameters such as the coefficient of determination (R²), root mean square error and design of index (d).

Cloud point extraction (CPE) factors, namely Triton X-114 (TX-114) concentration, pH, ionic strength, incubation time, and temperature, were optimized for the separation of nano-sized copper(II) oxide (nCuO) in aqueous matrices. The kinetics of phase transfer was studied using UV–visible spectroscopy. From the highest separation rate, the most favorable conditions were observed with 0.2 % w/v of TX-114, pH = 9.0, ionic strength of 10 mM NaCl, and incubation at 40 °C for 60 min, yielding an extraction efficiency of 89.2 ± 3.9 % and a preconcentration factor of 86. The aggregate size distribution confirmed the formation of very large nCuO–micelle assemblies (11.9 μm) under these conditions. The surface charge of nCuO was also diminished effectively. An extraction efficiency of 91 % was achieved with a mixture of TX-100 and TX-114 containing 30 wt.% of TX-100. Natural organic and particulate matters, represented by humic acid (30 mg/L) and micron-sized silica particles (50 mg/L), respectively, did not significantly reduce the CPE efficiency (<10 %). The recovery of copper(II) ions (20 mg/L) in the presence of humic acid was low (3–10 %). The spiked natural water samples were analyzed either directly or after CPE by inductively coupled plasma mass spectrometry following acid digestion/microwave irradiation. The results indicated the influence of matrix effects and their reduction by CPE. A delay between spiking nCuO and CPE may also influence the recovery of nCuO due to aggregation and dissolution. A detection limit of 0.04 μg Cu/L was achieved for nCuO.

The snow capacity for storage of a large number of pollutants such as polybromodiphenyl ethers (PBDE), including BDE-209, polycyclic aromatic hydrocarbons (PAHs), polychlorobiphenyls (PCBs), hexachlorocyclohexanes (HCHs; α- and γ-isomers), endosulfans (α- and β-isomers and the sulphate residue) and hexachlorobenzene (HCB), in a steep altitudinal gradient (1,101–2,500 m above sea level (asl); maximum planar distance 16 km) in a typical European mountain system, the Tyrolean Alps (Austria), was studied here for the first time. Snow samples representing the whole snowpack accumulated at the end of the cold season were collected in all cases. The snow specific surface area (SSA) of these samples, 140–260 cm² g⁻¹, was characteristic of aged snow with low retention capacity. PAHs were the pollutant group in highest concentrations (500–8,400 pg L⁻¹). PCBs and PBDEs were found in concentrations of 460–900 and 8.5–290 pg L⁻¹, respectively. From the fourteen investigated BDE congeners, only BDE-47, BDE-99, BDE-100 and BDE-209 were found above the detection limit, which is consistent with the results found in the only previous study in the Tatra Mountains (Slovakia) which also involved a steep gradient (1,683–2,634 m asl; maximum planar distance 5 km; Arellano et al. 2011) and confirm the capacity of these low-volatile compounds for long-range transport from distant sources. HCB was found in a concentration range of 34–55 pg L⁻¹. Snow deposition fluxes of PCB-118, PCB-153, γ-HCH, α-endosulfan and BDE-47 showed statistically significant correlations with altitude, involving higher values at higher elevation. This trend may reflect cold trapping effects in view of the snow particle contents and SSA values. However, these gradients were only significant for this limited number of compounds within each pollutant group which may be explained by differences in physical-chemical properties of the compounds and the limited capacity of the aged snow for organic pollutant retention. In some other cases, for example benzo[a]pyrene, the observed vertical gradients may reflect higher preservations at lower temperatures.

The 14th European Association of Chemical and Molecular Sciences (EuCheMS) International Conference on Chemistry and the Environment (ICCE 2013) took place on 25–28 June 2013 at the IEC and the WTC in Barcelona, Spain. The ICCE is a well-established biannual conference organized by the Division of Chemistry and the EuCheMS.