TiO2:Nb nanopowders within a dopant concentration in the range of 0.1–15 at.% were prepared by one-step flame spray synthesis. Effect of niobium doping on structural, optical and photocatalytic properties of titanium dioxide nanopowders was studied. Morphology and structure were investigated by means of Brunauer–Emmett–Teller isotherm, X-ray diffraction and transmission electron microscopy. Diffuse reflectance and the resulting band gap energy were determined by diffuse reflectance spectroscopy. Photocatalytic activity of the investigated nanopowders was revised for the photodecomposition of methylene blue (MB), methyl orange (MO) and 4-chlorophenol under UVA and VIS light irradiation. Commercial TiO2-P25 nanopowder was used as a reference. The specific surface area of the powders was ranging from 42.9 m2/g for TiO2:0.1 at.% Nb to 90.0 m2/g for TiO2:15 at.% Nb. TiO2:Nb particles were nanosized, spherically shaped and polycrystalline. Anatase was the predominant phase in all samples. The anatase-related transition was at 3.31 eV and rutile-related one at 3.14 eV. TiO2:Nb nanopowders exhibited additional absorption in the visible range. In comparison to TiO2-P25, improved photocatalytic activity of TiO2:Nb was observed for the degradation of MB and MO under both UVA and VIS irradiation, where low doping level (Nb < 1 at.%) was the most effective. Niobium doping affected structural, optical and photocatalytic properties of TiO2. Low dopant level enhanced photocatalytic performance under UVA and VIS irradiation. Therefore, TiO2:Nb (Nb < 1 at.%) can be proposed as an efficient selective solar light photocatalyst.

BACKGROUND: Polyvinyl alcohol (PVA) has been widely used as sizing agents in textile and manufacturing industry, and it is a refractory compound with low biodegradability. OBJECTIVE: The objective of this paper was to treat the PVA-containing wastewater using gamma irradiation as a pretreatment strategy to improve its biodegradability and to determine the roles of different kinds of radical species played during pretreatment. METHODS: Gamma radiation was carried out in a 60Cobalt source station, PVA concentration was analyzed by using a visible spectrophotometer and specific oxygen uptake rate (SOUR, milligram of O2 per gram of mixed liquor volatile suspended solids (MLVSS) per hour) was measured by a microrespirometer. RESULTS: The results showed that the biodegradability of PVA-containing wastewater with low initial concentration (e.g., 327.8 mg/l) could be improved greatly with increasing irradiation dose. However, PVA gel formation was observed at higher initial PVA concentration (e.g., 3,341.6 mg/l) and higher irradiation dose, which inhibited PVA degradation by aerobic microorganisms. However, the formed gel could be separated by microfiltration, which led to more than 90% total organic carbon (TOC) removal. CONCLUSION: Ionizing radiation could be used as a pretreatment technology for PVA-containing wastewater, and its combination with biological process is feasible.

PURPOSE: This study aims to examine whether addition of immobilising agents to a sandy, alkaline (pH = 8.1) soil, which had been contaminated with Pb and Zn by airborne particles from a Pb/Zn smelter, would substantially reduce metal bioavailability. METHODS: The effectiveness of five waste materials (blast furnace (BF) slag, alum water treatment (WT) sludge, red mud, sugar mill mud and green waste compost) as metal immobilising agents was evaluated by incubating them with a contaminated soil for a period of 12 months at rates of 5% and 10% (w/w), after which, Rhodes grass was grown in the soils in a greenhouse study. RESULTS: Additions of WT sludge, BF slag and red mud reduced CaCl2, CH3COOH, HCl and EDTA-extractable Zn but compost and mill mud had no appreciable immobilising effects. Additions of all amendments reduced levels of CaCl2, CH3COOH and HCl-extractable Pb although concentrations of EDTA-extractable Pb remained unchanged. A sequential extraction procedure showed that additions of mill mud and compost increased the percentage of total Pb and Zn present in the oxidisable fraction whilst additions of the other materials increased the percentage present in the residual fraction. Rhodes grass yields were promoted greatly by additions of red mud, compost and particularly mill mud, and yields were negatively correlated with tissue Pb concentrations and extractable Pb. CONCLUSIONS: Red mud was the most effective material for lowering extractable Pb and Zn levels simultaneously while mill mud and compost were notably effective for Pb. A field evaluation in the study area is justified.

Electric arc furnaces (EAF) are well recognized as significant sources of dioxins. EAFs have also been speculated to be sources of polychlorinated naphthalenes (PCNs) due to the close correlation between dioxin and PCN formation. However, assessment on PCN emissions from EAFs has not been carried out. The primary aim of this preliminary study is to identify and characterize the atmospheric emission of PCNs from EAFs. In this preliminary study, stack gas samples from two typical EAFs with different scales (EAF-1, 160 t batch−1; and EAF-2, 60 t batch−1) were collected by automatic isokinetic sampling technique, and PCN congeners in samples were analyzed by isotope dilution high-resolution gas chromatography combined with high-resolution mass spectrometry method. Emission concentrations of PCNs were 458 and 1,099 ng m−3 for EAF-1 and EAF-2, respectively. The emission factors of PCNs to air were 21.6 and 30.1 ng toxic equivalent t−1 for EAF-1 and EAF-2, respectively, which suggested that EAF is an important source of PCN release. With regard to the characteristics of PCNs from EAFs, lower chlorinated homologues were dominant. The PCN congeners comprised of CN27/30, CN52/60, CN66/67, and CN73 were the most abundant congeners for tetra-, penta-, hexa-, and hepta-chlorinated homologues, respectively. EAFs were identified to be an important PCN source, and the obtained data are useful for developing a PCN inventory. The congener profiles of PCNs presented here might provide helpful information for identifying the specific sources of PCNs emitted from EAFs.

GOAL, SCOPE, AND BACKGROUND: Many studies have focused on measuring fine and course particulate matter (PM) in urban and rural sites around the world. The aim of this research is to gain information on the size distribution of particles. The physical characteristics of PM in the urban air of Istanbul were determined. METHODS: PM sampling was carried out at five stations (Avcılar, Beşiktaş, Kilyos, Rasathane, and Göztepe) over a period of 2 years. PM filter samples were collected for eight different size ranges (<0.43, 0.43–1, 1–1.7, 1.7–2.6, 2.6–3.5, 3.5–5.2, 5.2–6.5, 6.5–8, and >8 μm) using a Cascade Impactor. The size distributions of the PM samples were determined. RESULTS AND DISCUSSION: The mean total PM concentrations were 48.6 ± 34.0, 34.8 ± 11.6, 28.6 ± 13.6, 21.5 ± 9.1, and 16.8 ± 5.1 μg/m3 for the Göztepe, Beşiktaş, Avcılar, Rasathane, and Kilyos stations, respectively. The total PM concentrations were found to be 1.2–1.5 times higher in the fall and winter than in the spring and summer, except for at the station in Avcılar. The PM concentrations in Avcılar did not exhibit seasonal variations. This is thought to result from the intense industrial activity in the area. PM2.6 (below 2.6 μm particles) comprised up to 62% of the total amount of PM in samples collected at the Göztepe, Beşiktaş, and Rasathane stations during the fall and winter. PM1 was determined to be approximately 45% of the total, corresponding to 57% of the amount of PM2.5. A multi-modal PM size distribution was observed. The lowest Mass Median Aerodynamic Diameter (MMAD) values observed in Avcılar, Beşiktaş, Rasathane, and Göztepe were 4.2, 3.9, 2.9, and 3.5 μm, respectively, and were observed during the season of active household heating. No difference was measured in the MMAD values (5.2 μm) between the seasons of heating and non-heating in Kilyos.

INTRODUCTION: The use of veterinary drugs in food production focuses on the control and improvement of animal health. The disadvantage of this practice is that pharmaceuticals and their metabolites are released into the environment, finding their way to natural water systems and becoming a potential risk to non-target organism. METHODS: This paper reports the development and validation of a quantitative method, based on high-performance liquid chromatography coupled to tandem mass spectrometry, for the simultaneous analysis of 21 veterinary drugs, antimicrobials, corticosteroids, coccidiostats and antifungal agents, in surface water. RESULTS: The precision of the method was established by calculating the mean recoveries, which were in the range of 94–101%. The developed method was employed to conduct the first monitoring study on the presence of veterinary drugs in the Galicia region, Northwest of Spain and was applied to 235 surface water samples. Eleven veterinary drugs were detected at concentrations from below the limit of quantification to 2,978.6 ng L−1. Limits of detection and quantification were in the range of 6.2 (betamethasone, cortisone, decoquinate, dexamethasone, maduramycin, monensin, narasin, salinomycin, sulfachloropyridazine, sulfamethoxypyridazine and trimethoprim) to 12.5 ng L−1 (for the rest of the selected drugs) and 12.5 (betamethasone, cortisone, decoquinate, dexamethasone, maduramycin, monensin, narasin, salinomycin, sulfachloropyridazine, sulfamethoxypyridazine and trimethoprim) to 25.0 ng L−1 (for the remaining pharmaceuticals), respectively. CONCLUSION: Sulfonamides were the group most frequently found, which are widely used in veterinary medicine.

INTRODUCTION: This study was hypothesized that salicylic acid elevates the level of antioxidant system that will protect plants from the stress generated by nickel and/or salinity. MATERIALS AND METHODS: Seeds of Brassica juncea were sown in sand amended with NiCl2 (100 mg kg−1) and/or 15-day-old seedlings supplied for 3 days with NaCl (150 mM) and were then, at 20-day stage, sprayed with salicylic acid (10−5 M) to assess selected morphological, physiological, and biochemical parameters at 30-day stage. RESULTS: The combination of Ni and NaCl proved most deleterious and exhibited significant decline in growth, leaf water potential, the level of pigments, and photosynthetic attributes. However, the follow-up treatment with salicylic acid detoxified the stress-generated damages caused by the combination (NiCl2 and NaCl) and also significantly improved values for the above parameters. The NiCl2 and/or NaCl increased electrolyte leakage, lipid peroxidation, and H2O2 content but decreased the membrane stability index and activity of nitrate reductase and carbonic anhydrase. However, the salicylic acid treatment in the presence or absence of the stress improved the activity of nitrate reductase and carbonic anhydrase. The activity of antioxidative enzymes and the level of proline exhibited a significant increase in response to NiCl2 and/or NaCl stress and which enhanced further with the spray of salicylic acid. CONCLUSIONS: It is concluded that the elevated level of antioxidative enzymes and level of proline might be responsible for minimizing the Ni and/or salinity-induced toxicity in Indian mustard which is manifested in terms of improved growth and photosynthesis.

INTRODUCTION: Organic pollutants, especially synthetic organic compounds, can indicate paces of anthropogenic activities. Effects of urbanization on polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) distributions in surface sediment were conducted in urban sections of the Grand Canal, China, consisting of a four-level urbanization gradient. MATERIALS AND METHODS: The four-level urbanization gradients include three countryside towns, two small-size cities, three medium-size cities, and a large-size city. Diagnostic ratio analysis and factor analysis–multiple linear regression model were used for source apportionment of PAHs. Sediment quality guidelines (SQGs) of USA and Canada were employed to assess ecological risks of PAHs and PCBs in surface sediments of the Canal. RESULTS AND DISCUSSION: Ranges of PAH and PCB concentrations in surface sediments were 0.66–22 mg/kg and 0.5–93 μg/kg, respectively. Coal-related sources were primary PAH sources and followed by vehicular emission. Total concentration, composition, and source apportionment of PAHs exhibited urbanization gradient effects. Total PCB concentrations increased with the urbanization gradient, while total PAHs concentration in surface sediments presented an inverted U Kuznets curve with the urbanization gradient. Elevated concentrations of both PAHs and PCBs ranged at effect range low levels or interim SQG, assessed by USA and Canadian SQGs. CONCLUSIONS: PAHs and PCBs in surface sediments of the Grand Canal showed urbanization gradient effects and low ecological risks.

BACKGROUND AND PURPOSE: Estrogenic compounds and antibiotic residues in environment are receiving significant attention because of their potential adverse effects on ecosystems and human health. The objectives of this study were to determine the occurrence and seasonal variability of eight kinds of estrogenic compounds and 14 antibiotics. The study developed an occurrence database of the estrogenic compounds and antibiotics in spatial and temporal scale in Jiulongjiang River, South China, to provide useful information for environmental management of this region. METHODS: Eight estrogenic compounds and 14 antibiotic compounds were detected in Jiulongjiang River from 19 sampling sites during high-flow and low-flow season in surface water. The samples were preconcentrated by solid-phase extraction for analysis. Eight estrogenic compounds were analyzed by gas chromatography mass spectrometry (Agilent 7890A-5975C), and antibiotics were determined by liquid chromatography-tandem mass spectrometry (LC–MS/MS) system (ABI 3200 Q TRAP). RESULTS: All target compounds could be detected, except 17α-ethynylestradiol, sulfamerazine, and ofloxacin. The median concentrations for seven estrogenic compounds ranged from 6.00 to 610.72 ng/L, with the detection frequency range of 16.00–100%. However, the detection frequencies of 13 antibiotics detected varied from 50% to 100%, with the median concentrations ranged from 0.89 to 117.97 ng/L. Seasonal variations were obvious for most estrogenic compounds in Jiulongjiang River, except for octylphenol and estriol. There were significant (P < 0.001) differences for three tetracyclines, sulfadiazine, and sulfamethoxazole between in low-flow season and in high-flow season. Besides, spatially considerable variations in the concentrations were observed for antibiotics, nonylphenol, octylphenol, and bisphenol A. CONCLUSION: The Jiulongjiang River water was more seriously contaminated by diethylstilbestrol, estrone, sulfamethazine, and tetracyclines. Higher overall concentration levels of estrogenic compounds and antibiotics were detected in low-flow water than those in high-flow water. The pollution of estrogenic compounds and antibiotics in Jiulongjiang River mainly came from municipal sewage and livestock breeding activities.

Concentrations of air pollutants, nitrogen dioxide (NO2), sulfur dioxide (SO2), ozone (O3), particulate matter (PM2.5 and PM10), trace metals, and polycyclic aromatic hydrocarbons (PAHs) were measured in 2008 and 2009 in the city of Eskişehir, central Turkey. Spatial distributions of NO2, SO2, and ozone were determined by passive sampling campaigns carried out during two different seasons with fairly large spatial coverage. A basic population exposure assessment was carried out employing Geographical Information System techniques by combining population density maps with pollutant distribution maps of NO2 and SO2. It was found that 95 % of the population is exposed to NO2 levels close to the World Health Organization guideline value. Regarding SO2, a large proportion of the population (83 %) is exposed to levels above the WHO second interim target value. Concentrations of all the pollutants showed a seasonal pattern increasing in winter period, except for ozone having higher concentrations in summer season. Daily PM10 and PM2.5 concentrations exceeded European Union limit values almost every sampling day. Toxic fractions of the measured PAHs were calculated and approximately fourfold increase was observed in winter period. Copper, Pb, Sn, As, Cd, Zn, Sb, and Se were found to be moderately to highly enriched in PM10 fraction, indicating anthropogenic input to those elements measured. Exposure assessment results indicate the need for action to reduce pollutant emissions especially in the city center. Passive sampling turns out to be a practical and economical tool for air quality assessment with large spatial coverage.