PURPOSE: The major aromatic constituents of petroleum products viz. benzene, toluene, and mixture of xylenes (BTX) are responsible for environmental pollution and inflict serious public concern. Therefore, BTX biodegradation potential of individual as well as formulated bacterial consortium was evaluated. This study highlighted the role of hydrogen peroxide (H2O2), nitrate, and phosphate in stimulating the biodegradation of BTX compounds under hypoxic condition. MATERIALS AND METHODS: The individual bacterium viz. Bacillus subtilis DM-04 and Pseudomonas aeruginosa M and NM strains and a consortium comprising of the above bacteria were inoculated to BTX-containing liquid medium and in soil. The bioremediation experiment was carried out for 120 h in BTX-containing liquid culture and for 90 days in BTX-contaminated soil. The kinetics of BTX degradation either in presence or absence of H2O2, nitrate, and phosphate was analyzed using biochemical and gas chromatographic (GC) technique. RESULTS: Bacterial consortium was found to be superior in degrading BTX either in soil or in liquid medium as compared to degradation of same compounds by individual strains of the consortium. The rate of BTX biodegradation was further enhanced when the liquid medium/soil was exogenously supplemented with 0.01 % (v/v) H2O2, phosphate, and nitrate. The GC analysis of BTX biodegradation (90 days post-inoculation) in soil by bacterial consortium confirmed the preferential degradation of benzene compared to m-xylene and toluene. CONCLUSIONS: It may be concluded that the bacterial consortium in the present study can degrade BTX compounds at a significantly higher rate as compared to the degradation of the same compounds by individual members of the consortium. Further, addition of H2O2 in the culture medium as an additional source of oxygen, and nitrate and phosphate as an alternative electron acceptor and macronutrient, respectively, significantly enhanced the rate of BTX biodegradation under oxygen-limited condition.

PURPOSE AND AIM: The present study provides an optimization of electrocoagulation process for the simultaneous removal of heavy metals such as mercury, lead, and nickel from water. In doing so, the thermodynamic, adsorption isotherm and kinetic studies were also carried out. MATERIALS AND METHODS: Magnesium alloy, magnesium, aluminum, and mild steel sheet of size 2 dm² were used as anode and galvanized iron as cathode. To optimize the maximum removal efficiency, different parameters like effect of initial concentration, effect of temperature, pH, and effect of current density were studied. Mercury-, lead-, and nickel-adsorbed magnesium hydroxide coagulant was characterized by SEM and EDAX. RESULTS: The results showed that the maximum removal efficiency was achieved for mercury, lead, and nickel with magnesium alloy as anode and galvanized iron as cathode at a current density of 0.15 Å/dm² and pH of 7.0. The adsorption of mercury, lead, and nickel are preferably fitting the Langmuir adsorption isotherm suggests monolayer coverage of adsorbed molecules. The adsorption process follows second-order kinetics. Temperature studies showed that adsorption was endothermic and spontaneous in nature. CONCLUSIONS: The magnesium hydroxide generated in the cell removes the heavy metals present in the water and reduces to a permissible level, making it drinkable.

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.

PURPOSE: The disinfection efficiency of water and secondary treated wastewater by means of photoelectrocatalytic oxidation (PEC) using reference strains of Enterococcus faecalis and Escherichia coli as faecal indicators was evaluated. Operating parameters such as applied potential (2–10 V), initial bacterial concentration (103–107 CFU/mL), treatment time (up to 90 min) and aqueous matrix (pure water and treated effluent) were assessed concerning their impact on disinfection. METHODS: PEC experiments were carried out using a TiO2/Ti film anode and a zirconium cathode in the presence of simulated solar radiation. Bacterial inactivation was monitored by the culture method and real-time SYBR green PCR. RESULTS: A 6.2 log reduction in E. faecalis population was achieved after 15 min of PEC treatment in water at 10 V of applied potential and an initial concentration of 107 CFU/mL; pure photocatalysis (PC) led to only about 4.3 log reduction, whilst negligible inactivation was recorded when the respective electrochemical oxidation process was applied (i.e. without radiation). PEC efficiency was generally improved increasing the applied potential and decreasing initial bacterial concentration. Regarding real wastewater, E. coli was more susceptible than E. faecalis during treatment at a potential of 5 V. Wastewater disinfection was affected by its complex composition and the contained mixed bacterial populations, yielding lower inactivation rates compared to water treatment. Screening the results obtained from both applied techniques (culture method and real-time PCR), there was a discrepancy regarding the recorded time periods of total bacterial inactivation, with qPCR revealing longer periods for complete bacterial reduction. CONCLUSIONS: PEC is superior to PC in terms of E. faecalis inactivation presumably due to a more efficient separation and utilization of the photogenerated charge carriers, and it is mainly affected by the applied potential, initial bacterial concentration and the aqueous matrix.

BACKGROUND AND OBJECTIVE: Spills of heavy oil (HO) over the oceans have been proven to have an adverse effect on marine life. It has been hypothesized that exposure of early larvae of sinking eggs to HO leads largely to normal morphology, whereas abnormal organization of the developing neural scaffold is likely to be found. HO-induced disruption of the nervous system, which controls animal behavior, may in turn cause abnormalities in the swimming behavior of hatched larvae. To clarify the toxicological effects of HO, we performed exposure experiments and morphological and behavioral analyses in pufferfish (Takifugu rubripes) larvae. EXPERIMENTAL PROCEDURE: Fertilized eggs of pufferfish were exposed to 50 mg/L of HO for 8 days and transferred to fresh seawater before hatching. The hatched larvae were observed for their swimming behavior, morphological appearance, and construction of muscles and nervous system. RESULTS AND DISCUSSION: In HO-exposed larvae, we did not detect any anomaly of body morphology. However, they showed an abnormal swimming pattern and disorganized midbrain, a higher center controlling movement. Our results suggest that HO-exposed fishes suffer developmental disorder of the brain that triggers an abnormal swimming behavior and that HO may be selectively toxic to the brain and cause physical disability throughout the life span of these fishes.

Large day-to-day variability in O3 and CO was observed at Chongming, a remote rural site east of Shanghai, in August 2010. High ozone periods (HOPs) that typically lasted for 3–5 days with daily maximum ozone exceeding 102 ppb were intermittent with low ozone periods (LOPs) with daily maximum ozone less than 20 ppb. The correlation analysis of ozone with meteorological factors suggests that the large variations of surface ozone are driven by meteorological conditions correlated with the changes in the location and intensity of the west Pacific subtropical high (WPSH) associated with the East Asian summer monsoon (EASM). When the center of WPSH with weaker intensity is to the southeast of Chongming site, the mixing ratios and variability of surface ozone are higher. When the center of WPSH with stronger intensity is to the northeast of Chongming site, the mixing ratios and variability of surface ozone are lower. Sensitivity simulations using the GEOS-Chem chemical transport model indicate that meteorological condition associated with WPSH is the primary factor controlling surface ozone at Chongming in August, while local anthropogenic emissions make significant contributions to surface ozone concentrations only during HOP.

INTRODUCTION: The reuse of wastewaters for agricultural purposes is a common practice in many countries and is increasingly recommended by organizations that promote sustainable development. Yet, it is restricted by the potential negative impact of these materials on soil and crops. The aim of this study was therefore to evaluate the environmental impact of walnut husk washing waters (WHWW) and their organic fractions, in order to conceive their agricultural exploitation. DISCUSSION: Phytotoxicity tests and morphological investigations on representative plant species of horticultural interest indicated that WHWW and their organic fractions can elicit a concentration-dependent stimulating effect on the growth of radish, lettuce cv. cavolo Napoli with effects up to 165 %. An opposite inhibitory effect up to 70 % was observed on spinach and lettuce cv. Gentilina. Proapoptotic effects were observed by acridine orange/ethidium bromide assay in the species inhibited by WHWW treatment. High-performance liquid chromatography–mass spectrometry analysis of the WHWW revealed the presence of a main component which was extracted selectively in organic solvents and purified by preparative chromatography. Complete spectral analysis allowed identification as 4,8-dihydroxy-1-tetralone, commonly known as regiolone. Regiolone exhibited the same concentration-dependent activity on root elongation with a stimulation in the case of radish up to 135 % with respect to control. These results open perspectives in the exploitation of WHWW and the main phenolic constituent readily available by a straightforward isolation procedure as a natural fertilizer for specific crops.

INTRODUCTION: The content of 16 polycyclic aromatic hydrocarbons (PAHs) was determined in 60 samples from three environmental matrices (soils, sediments, and pine needles) in an effort to assess their distribution on a river basin scale. METHODS: A sampling campaign was carried out in 2006, selecting urban, industrial, and agricultural sampling sites along the northeast of Spain. Techniques used included pressurized liquid extraction and solid–liquid ultrasonic extraction followed by gas chromatography-electron impact ionization mass spectrometry. RESULTS: The mean total PAHs concentrations were 290 < 613 < 1,628 ng/g (dry weight) in pine needles, soil, and sediments, respectively. There is a good correspondence between the total concentration of soils and pine needles, as opposed to the levels between sediments and pine needles. The high concentrations found in some Pinus halepensis samples may reflect a superior uptake potential of this species in comparison to the others studied. The three matrices present a very different PAH distribution pattern, with pine needles showing a predominance of the lighter (2-, 3-, and 4-ring) PAHs, whereas 5- and 6-ring PAHs are the most abundant in soils. Sediments display a more heterogeneous pattern, with contributions of all the PAHs but different distribution depending on the site, suggesting a wider range of input sources. Established PAH molecular ratios and principal component analysis were used to identify the origins and profiles of PAHs. While sediments showed a wide range attributed to historical inputs, soils and pine needles confirmed the compartmentalization of the PAHs, with lighter airborne PAHs accumulated in pine needles and heavier ones in soils. CONCLUSIONS: It can be suggested that the monitoring of several matrices is a strong tool to elucidate the contamination sources and accumulation patterns of PAHs. However, given the influence of the matrix type on this assessment, the information should be considered complementary, yet allowing a more comprehensive depiction of the area in question.

This field study investigated the phytoremediation potential of two arsenic (As) hyperaccumulating fern species, Pityrogramma calomelanos var. austroamericana and Pteris vittata over 27-month duration at a disused As-contaminated cattle-dip site located at Wollongbar, NSW, Australia. Ferns planted in January 2009 were harvested following 10, 22 and 27 months of growth. A detailed soil sampling was undertaken in June 2009 (initial, n = 42 per plot) and limited sampling in April 2011 (after 27 months, n = 15 per plot) to measure total and phosphate-extractable As concentrations in soil at 0 − 20-, 20 − 40- and 40 − 60-cm depths. The choice of the limited number of samples was considered sufficient to estimate the changes in soil As concentration following phytoremediation based on a geostatistical model. The average frond dry biomass, As concentration and As uptake were significantly (P < 0.001 − 0.05) greater in P. calomelanos var. austroamericana than P. vittata, at all three harvests (1.6 − 4.3, 1.3 − 1.5 and 2.2 − 5.7 times, respectively). After 27-months of growth, P. calomelanos var. austroamericana removed 8,053 mg As (i.e. cumulative over three harvests) in plot B (25.4 kg As ha−1) that was 2.65 times higher than that depleted by P. vittata (3,042 mg As in plot A (9.7 kg As ha−1)). The cumulative frond As uptake data of the two fern species revealed that P. calomelanos var. austroamericana extracted 1.7 − 3.9 % and P. vittata removed 0.53 − 1.5 % of total As from soil at three depths. However, for the surface (0 − 20 cm) and subsurface (40 − 60 cm) layers, the (post-experiment) soil As data indicated that total As concentration in soil was reduced by 49 and 63 % (P < 0.05), respectively, using P. calomelanos var. austroamericana; and 17 and 15 % (P > 0.05), respectively, by P. vittata. Our results show that phytoremediation time based on observed changes in soil As based on limited sampling is not reliable; hence, it is recommended that the frond As uptake should be considered in order to evaluate the phytoremediation efficiency of the two fern species at the experimental site. Using As uptake of the two fern species, we estimate that with P. calomelanos var. austroamericana it would take 55 − 125 years to decrease mean total As content below the ecological investigation level (20 mg kg−1) in the surface and subsurface soils, whereas with P. vittata 143 − 412 years would be required to achieve this target.

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.