Fe₃O₄and Fe₃O₄/bentonite were prepared by chemical co-precipitation method. They were characterized by X-ray powder diffraction (XRD), Fourier infrared spectroscopy (FTIR), and transmission electron microscope (TEM). Adsorption of cobalt(II) on the bentonite, Fe₃O₄, and Fe₃O₄/bentonite nanocomposite was studied. The results indicated that the metal oxides mainly occurred in the form of spinel structure of Fe₃O₄and the presence of Fe₃O₄significantly affect the surface area and pore structure of the bentonite. The specific surface area (Brunauer–Emmett–Teller (BET) method) of bentonite, Fe₃O₄, and Fe₃O₄/bentonite were determined to be 34.44, 98.44, and 140.5 m² g⁻¹, respectively. TEM image of Fe₃O₄/bentonite shows the particle diameter at 10 nm. The maximum adsorption capacity of cobalt(II) by Fe₃O₄/bentonite nanocomposite was determined to be 18.76 mg g⁻¹. The adsorption strongly depends on pH, where the removal efficiency increases as the pH turns to alkaline range (pH 9). The results suggest that higher adsorption capacity of composite than bentonite is attributed to the presence of Fe₃O₄. The adsorption process follows pseudo-second-order kinetics. The equilibrium data was analyzed by Langmuir model showing high correlation coefficient. The thermodynamic study of adsorption process showed that the adsorption of Co(II) onto Fe₃O₄/bentonite was carried out spontaneously.

Tropical coastal areas are sensitive ecosystems to climate change, mainly due to sea level rise and increasing water temperatures. Furthermore, they may be subject to numerous stresses, including heat releases from energy production. The Urias coastal lagoon (SE Gulf of California), a subtropical tidal estuary, receives cooling water releases from a thermoelectric power plant, urban and industrial wastes, and shrimp farm discharges. In order to evaluate the plant thermal impact, we measured synchronous temperature time series close to and far from the plant. Furthermore, in order to discriminate the thermal pollution impact from natural variability, we used a high-resolution hydrodynamic model forced by, amongst others, cooling water release as a continuous flow (7.78 m³ s⁻¹) at 6 °C overheating temperature. Model results and field data indicated that the main thermal impact was temporally restricted to the warmest months, spatially restricted to the surface layers (above 0.6 m) and distributed along the shoreline within ∼100 m of the release point. The methodology and results of this study can be extrapolated to tropical coastal lagoons that receive heat discharges.

As the use of dangerous substances in consumer products increases, these substances may also be found in society’s end products, among them sewage sludge. Measuring concentrations in sewage sludge can be a way to reflect the consumption of a substance. By using substance flow analysis, the inflow, stock and outflow of the specific substance to, e.g. a city region, may be analysed. Bismuth is a heavy metal that is found in increasing levels in sewage sludge in Swedish wastewater treatment plants (WWTPs) and a similar increase cannot be excluded for WWTPs around the world. This study aims to examine possible sources that could explain the amounts measured in one Swedish WWTP. Household products such as cosmetics (24 %) and plastics (14 %) are found to be major sources of Bi measured in sewage sludge. The remaining unidentified amounts in this study (approximately 50 %) are most likely found in effluent waters from industries or sources outside the household. There is, however, no information on measurements of Bi released by industry available and there is no legislation in place that may encourage industry to conduct such measurements.

Recent droughts in the southwestern United States have heightened the interest in using more reclaimed water for agricultural irrigation. Treated wastewater effluent is a source of irrigation water and contains many pharmaceutical microcontaminants. Currently, there is little knowledge on if these microconstituents will enter food crops and if so where they will be found within the plant. For this experiment, the uptake of 17α-ethynylestradiol, fluoxetine HCl (Prozac®), and ibuprofen within different sections of a celery stalk over a 24-h time period was examined. Results found that all of these pharmaceuticals were taken up into the celery stalks within 24 h. Ibuprofen was found to have reached concentrations of 1 μg/g within the leaves in just 1 h. Metabolites of the ibuprofen were also detected at all locations within the stalk for all time periods. The concentration of EE2 in the submerged section of the stalk was found to increase from 0.031 to 0.911 μg/g of celery in just 23 h. The EE2 began to rise higher within the stalk to reach a concentration of 8.94 ng/g about 6 in above the base after 24 h. Fluoxetine HCl concentrations rose to 0.832 μg/g of celery within the submerged section of the stalk during the 24 h. After 12 h, fluoxetine HCl was detected within the bottom 4 in of the stalk. EE2, fluoxetine HCl, and ibuprofen all exhibit potential for uptake within food crops. Further studies on additional food crops and pharmaceuticals would be required to assess the full risk posed to human eating food crops irrigated with treated wastewater effluent.

The majority of the existing water bodies around the world are increasingly polluted with oily wastewater. The aim of this study was to investigate the role of single protozoan isolates (Aspidisca, Trachelophyllum and Peranema) and of a consortium of these three protozoan isolates in the biodegradation of fats and oils present in polluted domestic wastewater. The biomass of protozoan isolates, chemical oxygen demand (COD), dissolved oxygen (DO) and concentrations of fats and oils were determined in triplicate before and after the inoculation of isolates in oily wastewaters, using standard methods. Results revealed optimum growth of protozoan cell densities under favourable conditions of 30 °C, pH 6 and 8 (from 1.00 to 4.00, 3.96, 3.80 and 4.20 × 10²cells/ml for Aspidisca, Trachelophyllum, Peranema and a consortium of the three isolates, respectively). The average percentage uptake of DO by Aspidisca, Trachelophyllum, Peranema and their consortium was 95, 96, 96 and 100 %, respectively, for both 30 and 25 °C and at pH levels of (4, 6, 8 and 10), respectively. The results revealed that the COD removal rates of the isolates at various pH levels were ≥20 and ≤90 %, respectively, for 30 and 25 °C. At a temperature of 30 °C, the biodegradation capabilities of the isolates ranged from 3.0 to 8.0, 3.0 to 6.0, 7.0 to 11.0 and 8.0 to 22.0 %, while at 25 °C, the biodegradation rates were 3.0 to 6.0, 4.0 to 7.0, 3.0 to 8.0 and 4.0 to 15.0 % for Aspidisca, Trachelophyllum, Peranema and the consortium of these three isolates, respectively.

Exposure to benzene has been associated with multiple severe impacts on health. This notwithstanding, at most monitoring stations, benzene is not monitored on a regular basis. Data were used from two different monitoring stations located on the eastern Mediterranean coast: (1) a traffic monitoring station in Tel Aviv located in an urban region with heavy traffic and (2) a general air quality monitoring station in Haifa Bay located in Israel’s main industrial region. At each station, hourly, daily, monthly, seasonal, and annual data of benzene, NO ₓ , mean temperature, relative humidity, inversion level, and temperature gradient were analyzed over 3 years: 2008, 2009, and 2010. A prediction model for benzene rates based on NO ₓ levels (which are monitored regularly) was developed to contribute to a better estimation of benzene. The severity of benzene pollution was found to be considerably higher at the traffic monitoring station than at the general air quality station, despite the location of the latter in an industrial area. Hourly, daily, monthly, seasonal, and annual patterns have been shown to coincide with anthropogenic activities (traffic), the day of the week, and atmospheric conditions. A strong correlation between NO ₓ and benzene allowed the development of a prediction model for benzene rates based on NO ₓ , the day of the week, and the month. The model succeeded in predicting the benzene values throughout the year. The prediction model suggested in this study might be useful for identifying potential risk of benzene in other urban environments.

Soils exposed to long-term contamination with hydrocarbons may present extreme challenges to maintain the biological resilience to the stress. To elucidate the relationships between the initial event of contamination and the responsiveness to the stress, we investigated the extent of the microbial resilience of biological functions from two contaminated soils sampled from a petrochemical area (S1, underwent diffuse hydrocarbon contamination, and S2, from a land farming unit where an alkaline petrochemical sludge was treated) after the Cd, saline, and acid stresses. Both contaminated soils were characterized by low organic matter content compared with a pristine soil. Although similar Shannon diversity index and heterotrophic bacterial count were observed, different bacterial community structures (PCR-DGGE) and less enzymatic activities characterized the contaminated soils. Particularly, functional diversity determined by Biolog EcoPlates™ was not detected in S2 soil. Only the S1 soil showed resilience of the enzymatic activities and functional diversity, suggesting the presence of a well-adapted microbial community able to face with the stresses. The S2 was the most disturbed and less responsive soil. However, an increase in the functional diversity was evidenced after acidification, and it is possible to correlate this responsiveness with the sludge properties treated in the land farming unit. In addition, if the selected stress can reverse the soil condition provoked for the first disturbance, responsiveness could be expected.

Although recent studies show that the iron oxides do not enter or accumulate in plants, they may preclude the transport of water and nutrients in the plants through/as a consequence of their aggregation on the surface of the roots. The feasibility of using iron oxide nanoparticles to modify the availability of trace elements (TEs) to Helianthus annuus in the soil as well as their interference with the plant response during an imposed water deficiency stress were studied in a pot experiment. Plants were grown in a compost pre-amended contaminated soil with and without nano-maghemite (NM) and later exposed to drought. The nano-amendment promoted the growth of H. annuus (higher (25 %) dry weight than in the same soil without NM), mainly due to the insolubilisation of pore water Zn in the soil and the consequent reduction of its availability to the plants. During the water stress, NM did not cause an increase in the accumulation of proline or total amino acids in the plants, which are normally used as drought stress indicators, compared to the control plants without NM. In conclusion, NM could be useful soil amendments during phytoremediation procedures, since it can immobilise TEs in the soil without disrupting the plant water balance.

Nanoparticles have been used widely in industry and consumer products in recent years. Most of the engineered nanoparticles (NPs) eventually enter municipal wastewater treatment systems (WWTP) through sewers. In this experimental study, the impact of nano-TiO₂, nano-ZnO, and nano-Ag on methanogenesis was investigated during mesophilic batch anaerobic digestion of primary sludge. The experimental sets consisted of 1, 10 mg NP/g TS, and a control group for TiO₂NP, ZnO NP, and Ag NP, separately. The results showed that neither of the NPs used remarkably changed methane production. Methane yields in the units of m³CH₄/kg VS in were between 0.08 and 0.13 and showed no significant difference between the control groups and experimental sets for tested NPs. Soluble Ti concentrations were below 0.07 mg/L after the end of anaerobic digestion. Soluble Zn and soluble Ag concentrations were below 0.78 and 2.02 mg/L, respectively. Most of the NPs remained in the sludge rather than in aqueous supernatant. The authors suggest that the effects of the NPs, just above the sludge, or the NPs that adsorbed to sludge, on methanogenic activity at long-term exposure should be examined in the future studies.

The efficiency of phytoextraction is limited because of the low growth exhibited by plants under the stress of heavy metals. Impatiens (Impatiens walleriana) cuttings were grown in soils artificially contaminated with cadmium (Cd) and modified with chemical fertilizer to study the relationship among the leaf area, transpiration rate, and Cd accumulation. The subcellular distribution of Cd in various impatiens organs was also measured. Experimental results showed that there were positive, linear relationships between the leaf area and the transpiration rate. A similar relationship was found between the transpiration rate and the Cd accumulation in the shoots. Suitable management practices can be conducted to increase the transpiration rate and thus the plant’s phytoextraction efficiency. In the roots and leaves, Cd was mainly compartmentalized in the soluble fraction and the cell wall fraction, respectively. The varied subcellular distribution of Cd in the different organs was responsible for the high accumulation capacity.