Nanoscale zero valent iron (NZVI) supported on beta zeolite was synthesized by refined method for the removal of Sb(III) and characterized with TEM-EDX, XRD, XPS, BET, and Zetasizer. The results showed that NZVI existed as apparent ones doping on surface of beta zeolite (average size 20–40 nm) and fine ones formed in structure of beta zeolite (<1 nm). Compared to NZVI, NZVI-zeolite showed enhanced antimony removal ability and higher iron efficiency due to its better dispersibility and smaller size. Adsorption and reduction ability of iron played main roles in the antimony removal. The removal isotherm was better fitted by Freundlich model. According to XPS analysis, reduction of Sb(III) happened rapidly and Sb(0) took more than 80 % in final products, which was higher compared with NZI. Iron transformation accompanied with antimony removal was identified by XRD and XPS, which caused antimony reduction and facilitate further immobilization of removed antimony. The iron oxides encapsulated antimony in their own structure and beta zeolite which they adhere. The theoretical model about the process was proposed to illustrate NZVI-zeolite enhanced antimony removal ability.

Dioxins are a group of persistent organic pollutants with varying degrees of toxicity. To determine the effects of polychlorinated dibenzo-p-dioxins pollution on soil nutrition, soil carbon dioxide (CO₂) emission, and plant growth, soils and mung bean seedlings were experimentally subjected to 1,2,3,7,8-pentachlorodibenzo-para-dioxin (PeCDD). The results showed that: (i) Low dose of PeCDD treatments led to a significant decrease in the soil organic matter content and an increase in the hydrolyzable nitrogen content, while the contents of available phosphorus and exchangeable potassium decreased significantly at high doses of PeCDD (≥20 ng kg⁻¹). (ii) The soil CO₂release rate was gradually increased from treatments with 10 to 20 ng kg⁻¹PeCDD, but decreased significantly with 30 ng kg⁻¹PeCDD treatment after 25 days exposure. With prolonged exposure time, the soil CO₂emission after all treatments declined heavily, along with the difference among different treatments. (iii) Low dose of 10 ng kg⁻¹PeCDD resulted in significant reductions of malondialdehyde (MDA) content and electrolyte leakage conductivity and increases in the contents of chlorophyll and soluble protein and fresh biomass of mung bean seedlings. On the contrary, high doses of PeCDD (≥20 ng kg⁻¹) treatments showed opposite effects on the above parameters of seedling growth. The results suggested that high doses of PeCDD contamination (≥20 ng kg⁻¹) posed potential negative effects on the cycling processes of soil nutrients, which were probably due to the inhibitory on soil microbial activity, and induced phytotoxicity on seedling growth, although slight stimulations of soil microbial activity and mung bean seedling growth were found at low doses of PeCDD. Therefore, more efforts are needed to ensure the dioxin contamination below the toxic concentration of 20 ng TEQ kg⁻¹in farmland soil.

Soil is a primary resource used by mankind to ensure its needs mainly through agriculture. Its sustainability is regulated by the indigenous organisms it contains such as microorganisms. Current agricultural practices employ mixtures of pesticides to ensure the crops yield and can potentially impair these non-target organisms. However despite this environmental reality, studies dealing the susceptibility of microorganisms to pesticide mixtures are scarce. In this context, we designed a 3-month microcosm study to assess the ecotoxicity of realistic herbicide mixtures of formulated S-metolachlor (Dual Gold Safeneur®), mesotrione (Callisto®), and nicosulfuron (Milagro®) on the abundance, the diversity, and the activities of microorganisms from a “clay/organic matter-rich” soil, with a particular attention given to N-cycle communities. These communities appeared to be quite resistant to realistic mixtures even if transient effects occurred on the N-cycle-related communities with an increase of ammonification and an inhibition of nitrification as a short-term effect, followed by an increase of denitrification and an accumulation of nitrates. As nitrates are known to be highly leachable with a strong pollution potential, intensive studies should be carried out at field level to conclude on this potential accumulation and its consequences. Moreover, these data now need to be compared with other agricultural soils receiving these herbicide mixtures in order to bring general conclusion on such practices.

The paper presents a comprehensive analysis of the most basic features of the air quality of a Mediterranean urban environment area. The impact of meteorology on the air quality is also examined. Observational surface concentrations of the most important air pollutants, recorded at two measuring stations in Patras, Greece, are used. The Weather Research and Forecasting (WRF) meteorological model was employed to produce a series of surface and upper air data and local circulation and ventilation indices. These modeled data along with selected surface meteorological observational data comprise a substantial data set that was used to assess the effect of meteorology on the air quality. Mostly during the summer period, a significant proportion of the particulate matter is transported from sources away from the measuring sites. The synoptic setting of winter and summer seasons represented primarily by the local ventilation and recirculation, the wind, the boundary layer height, and the precipitation has a very strong impact in the overall formation of the air quality status.

In this study, nanosized zero-valent iron-reduced graphene oxide (nZVI-rGO)-activated persulfate (PS) was used to investigate the generation of reactive oxygen species (ROS) for the degradation of trichloroethylene (TCE) in the aqueous solution. More than 98 % of TCE was degraded within 2 min under experimental conditions. The generation of ·OH increased when the pH was shifted toward the basic region while ·SO₄⁻ radicals’ intensity increased in the acidic pH. Different scenarios have been observed in ·O₂⁻ generation in the neutral and strong basic pH and decreased in acidic or slightly basic pH. In addition, the intensity of ·OH was increased with the addition of HCO₃⁻ (10 mM) and NO₃⁻ (100 mM) but decreased in the presence of Cl⁻ (10 and 100 mM), HCO₃⁻ (100 mM), and NO₃⁻ (10 mM). The degradation of anisole, probe for both ·OH and ·SO₄⁻, was slightly enhanced by 10 mM NO₃⁻ anions but decreased in 100 mM salt solution. ·O₂⁻ intensity was increased while HCO₃⁻ (10 and 100 mM) and NO₃⁻ (100 mM) anions were used. nZVI-rGO-activated PS process could remove TCE in aqueous effectively, and the ROS generation and intensity were influenced by solution pH values and anions.

Sugarcane molasses, which is a kind of microbial carbon source, is a viscous by-product of the refining of sugarcane into sugar. However, experiments were designed to ascertain the mechanism and kinetics of Cr(VI) reduction with sugarcane molasses without adding microbes in aqueous solution. Results indicated that sugarcane molasses can reduce Cr(VI) to Cr(III) at pH values that range from 2.0 to 6.1 when no bioreduction occurs in the reaction. Furthermore, the reaction mechanism was proven to be that Cr(VI) acts as an electrophile that readily accepts electrons from the phenolic hydroxyl group of plant polyphenol, and it is then reduced to Cr(III) and in the process oxidizes the phenolic hydroxyl group to a quinone. Meanwhile, the reaction could be described by the pseudo-first-order kinetic model with respect to Cr(VI) concentration. The reaction rate constants were 324.2, 65.9, 21.9, and 14.4 h⁻¹ when pH values were 2.0, 3.5, 5.0, and 6.1, respectively, at 20 °C. The k ₒbₛ increased 3.36, 7.02, and 13.48 times with the temperature adjusted from 5 to 10, 20, and 30 °C.

Alkyl polyglucosides, due to their low toxicity and environmental compatibility, could be used in biodegradation of hydrophobic compounds. In this study, the influence of Lutensol GD 70 on the cell hydrophobicity and zeta potential was measured. The particle size distribution and surfactant biodegradation were also investigated. Microbacterium sp. strain E19, Pseudomonas stutzeri strain 9, and the same strain cultivated in stress conditions were used in studies. Adding surfactant to the diesel oil system resulted in an increase of the cell surface hydrophobicity and the formation of cell aggregates (a high polydispersity index). The correlation between cell hydrophobicity and zeta potential in examined samples was not found. The results showed a significant influence of Lutensol GD 70 on the changes in cell surface properties. Moreover, a high biodegradation of a surfactant (over 50 %) by tested strains was observed. The biodegradation of Lutensol GD 70 depends on the length of both polar and nonpolar chains. A long-term contact with diesel oil of stressed strain modifies not only cell surface properties but also its ability to a surfactant biodegradation.

The capability of W⁶⁺-impregnated ZnO photocatalysts for sunlight mineralization of a variety of structurally different dyes has been investigated. Compared to bare ZnO, the W⁶⁺-loaded photocatalysts showed significantly higher activity for the decolorization as well as mineralization of dyes, and complete mineralization was noticed in a short span of 150 min. The results obtained by various analytical tools were correlated to estimate the mechanistic aspects of the decolorization/mineralization process and to identify the nature of the oxidizing species involved in the process. A strong dependence of the decolorization/mineralization process was observed on the nature and number of auxochromes attached to color-generating conjugated system. The rapid decolorization/mineralization of the dyes and release of corresponding anions with the decolorization of dyes suggested the involvement of charged rather than radical reactive oxygen species (ROS) in the oxidation process. Langmuir-Hinshelwood kinetic model was found to be best suited for evaluating the kinetics of mineralization process. The effectiveness of the catalysts for the decolorization/mineralization of a mixture of dyes was also examined. The suitability of the catalysts for successive use in sunlight exposure was also evaluated.

The degradation of hexachlorobenzene (HCB) is of great concern and attracts considerable scientific and regulatory interests, due to the high toxicity, great bioaccumulation, and persistence of HCB in the environment. However, in the real HCB-contaminated soil, the effect of coexisting chlorobenzene congeners on the degradation capacity of HCB is poorly known. In this work, the anaerobic degradation behaviors of three coexisting chlorobenzene congeners pentachlorobenzene (PeCB), 1,2,4,5-tetrachlorobenzene (1,2,4,5-TeCB), and 1,2,4-trichlorobenzene (1,2,4-TCB) and the influence of initial pH and reaction temperature on the dechlorination of HCB in HCB-contaminated soil from the dye plant were studied. The amount and extent of accumulated coexisting chlorobenzenes was analyzed under different environmental conditions. The results indicate that the concentrations of three coexisting chlorobenzene congeners change in the form of wave. The anaerobic degradation activity of HCB is reduced due to the feedback inhibition caused by accumulation of coexisting chlorobenzene congeners, and the feedback inhibition varies from environmental conditions.

Concentrated animal feeding operations (CAFOs) are the principal means of livestock production in the USA and Europe, and these industrial-scale facilities have a high potential to pollute nearby waterways. Chemical and biological stream water quality of a swine and poultry CAFO-rich watershed was investigated on 10 dates during 2013. Geometric mean fecal coliform counts were in the thousands at five of seven sites, especially in locations near swine waste sprayfields. Nitrate concentrations were very high and widespread throughout the watershed, with some individual samples yielding >10 mg-N/L. Ammonium concentrations were likewise high, but greatest near swine waste sprayfields, ranging up to 38 mg-N/L. Five-day biochemical oxygen demand (BOD5) concentrations exceeded 10 mg/L in 11 of 70 stream samples, reaching as high as 88 mg/L. BOD5 concentrations were significantly correlated with components of animal waste including total organic carbon, ammonium, and phosphorus, as well as the nutrient response variable chlorophyll a. The degree of nutrient and fecal contamination did not significantly differ between rainy and dry periods, indicating that surface and groundwater pollution occurs independently of stormwater runoff. This research shows that industrial-scale swine and poultry production leads to chronic pollution that is both a human health and ecosystem hazard. There are approximately 450,000 CAFOs currently operating in the USA, with the majority located in watersheds feeding major riverine and estuarine systems with known water quality problems. Current US waste management protocols for this widespread system of livestock production fail to protect freshwater and estuarine ecosystems along the US Mid-Atlantic, Southeast and Gulf coasts, and expansion into industrializing nations will likely bring severe pollution with it.