Nanoscale zero-valent iron (nZVI) was synthesized and used for the removal of Sb(III) and Sb(V) from aqueous solutions. Results showed that more than 90 % of antimony would be removed in 15 min and that all of antimony could be removed with appropriate nZVI dosage in 90 min. The influence of pH value and possible impurities was investigated. The pH of 4 was found as the optimum pH. Discussion and speculation about the mechanism were presented according to X-ray photoelectron spectroscopy and transmission electron microscopy data. A sheet-like structure was observed after a 90-min reaction, and antimony was detected on the surface by energy-dispersive X-ray spectroscopy. Both Sb(III) and Sb(V) partially reduced in the process. The presence of humic acid transformed the morphology of nZVI but barely influenced the removal efficiency. Competing ions showed diverse influence between Sb(III) and Sb(V). The overall results indicated that nZVI was an efficient and suitable material for the removal of antimony.

The aim of this work was to study the short-term effect of clear-cut harvest on concentrations of dissolved organic carbon (DOC), B, Al, Zn, Cu, Ni, Cr, Cd and Pb in drainage water from northern peatland catchments in Finland underlain by granitic or black shale bedrock, the latter having higher concentrations of several trace elements, such as Ni and Zn. Stem-only harvest (SOH) or whole-tree harvest (WTH) with stump removal were carried out at coniferous sites. Controls were left unharvested. DOC and trace element concentrations were monitored during one pre-treatment and two post-treatment years. There was no constant increase in the element concentrations. However, there were signs that both SOH and WTH clear-cut harvest on northern peatland catchments increases the concentrations of DOC, B, Al, Zn and Ni in ditchwater in some sites irrespective of the bedrock type. The greatest increases were observed in WTH sites but the study does not allow us to assess the statistical significance of the magnitude of the difference between SOH and WTH. We conclude that the element concentrations in ditchwater depend largely on site characteristics masking the possible effect of harvest.

Zn²⁺was added to one of the two identical bench-scale upflow anaerobic sludge blanket (UASB) reactors in steady-state period treating swine wastewater to evaluate the effects of Zn²⁺on performance and methanogenic population. Real-time quantitative PCR (QPCR) was used to quantify the 16S rRNA gene concentrations of the four methanogenic orders. In both reactors, the hydraulic retention time (HRT) was sustained at 48 h and the inner temperature was kept at 35 °C. Both promotion and inhibition of Zn²⁺on chemical oxygen demand (COD) removal, methane production and methanogens community were observed in accordance with different Zn²⁺dosages. COD removal rate and methane production reacted in the same way as methanogens, suggesting that the impact of Zn²⁺on the methanogenic community was the critical reason that caused the changes of UASB performance in treating swine wastewater with unstable Zn²⁺concentration. Among the methanogenic community, Methanomicrobiales (MMB) was the dominant group which got visibly impacted by the dosed Zn²⁺. Overall, lower concentration of Zn²⁺, e.g., less than 17.8 mg/L, was supposed to be advisable for a stable and high efficient treatment of swine wastewater by UASB reactor in practice.

This study demonstrates the potential of a new BiOCl₀.₈₇₅Br₀.₁₂₅ photocatalyst to degrade pharmaceuticals in water (i.e., carbamazepine (CBZ), ibuprofen (IBF), bezafibrate (BZF), and propranolol (PPL)), under simulated solar irradiation. Different parameters were examined through their influence on CBZ degradation. Increasing the catalyst concentration up to 500 mg/L increased CBZ degradation rate; however, above 500 mg/L, CBZ degradation rate was slightly reduced, most likely due to the catalyst’s light-screening effect at high concentrations. Increasing the pH of the tested solution from 4 to 9 decreased the degree of CBZ adsorption to the catalyst and consequently its degradation rate. Quantum yield for CBZ degradation was found to be 0.75 ± 0.05 % using an integrating sphere for absorbance measurements to correctly account for scattering of light by the suspended catalyst. Degradation rates of all examined compounds (at pH 7) followed the order PPL > BZF > IBF > CBZ (highest rate for PPL). Interestingly, PPL was least adsorbed to the catalyst, implying that adsorption is not always mandatory for efficient degradation with BiOCl₀.₈₇₅Br₀.₁₂₅. Different adsorption mechanisms were hypothesized for the different pharmaceuticals, including hydrophobic attraction for the neutrally charged CBZ and ion exchange for the negatively charged IBF and BZF.

Land use specific deposition velocities of atmospheric trace gases and aerosols—particularly of reactive nitrogen compounds—are a fundamental input variable for a variety of deposition models. Although the concept is known to have shortcomings—especially with regard to bi-directional exchange—the often limited availability of concentration data and meteorological input variables make it a valuable simplification for regional modeling of deposition fluxes. In order to meet the demand for an up-to-date overview of recent publications on measurements and modeling studies, we compiled a database of ammonia (NH₃) deposition velocities published from 2004 to 2013. Observations from a total of 42 individual studies were averaged using an objective weighing scheme and classified into seven land use categories. Weighted average and median deposition velocities are 2.2 and 2.1 cm s⁻¹for coniferous forests, 1.5 and 1.2 cm s⁻¹for mixed forests, 1.1 and 0.9 cm s⁻¹for deciduous forests, 0.9 and 0.7 cm s⁻¹for semi-natural sites, 0.7 and 0.8 cm s⁻¹for urban sites, 0.7 and 0.6 cm s⁻¹for water surfaces, and 1.0 and 0.4 cm s⁻¹for agricultural sites, respectively. Thus, values presented in this compilation were considerably lower than those found in former studies (e.g., VDI 2006). Reasons for the mismatch were likely due to different land use classification, different averaging methods, choices of measurement locations, and improvements in measurement and in modeling techniques. Both data and code used for processing are made available as supplementary material to this article.

Recently, the World Health Organization’s International Association for Research on Cancer classified outdoor air pollution as carcinogenic to humans and puts air pollution in the same category as tobacco smoke, UV radiation, and plutonium. The ambient air is polluted by emissions from motor vehicles, industrial processes, power generation, household combustion of solid fuel, and other sources. Dust storms lead to particulate levels that exceed internationally recommended levels, especially near the Sahara. However, this source of air pollution appears to be under-studied, particularly in the literature devoted to human health impacts in West Africa. More than 50 % of the total dust emitted into the atmosphere comes from the Sahara. These aerosols contribute to increase the concentrations of particles smaller than 10 μm (PM₁₀), which are breathable particles. This study is the first designed to assess the real impact of Saharan dust on air quality and respiratory health of children in a region of West Africa. Dust events having affected the Northern Benin during the dry seasons between 2003 and 2007 were determined. The analyzed health data are the monthly rates of acute lower respiratory infections (ALRI). Over the entire study period, 61 days of dust events were observed in the region. They recorded on average a daily PM₁₀concentration of 1017 μg m⁻³, more than 18 times higher than that calculated on all days without dust events. The study also highlighted a mean increase of 12.5 % of ALRI rates during the months recording dust events. The use of daily health data should help to refine these initial results in the future.

Fluoride is among the most phytotoxic atmospheric pollutants, commonly linked to the appearance of lesions in susceptible plants around emitting sources. In order to assess the effects of fluoride on leaves of Spondias dulcis Parkinson (Anacardiaceae), plants were examined 78 km (non-polluted area) and 0.78 km (polluted area) from an aluminium smelter. The level of fluoride increased with the exposure time of the plants in the polluted area. On the third day of exposure in the polluted area, necroses with typical colouration were observed. Micromorphological damage began at the abaxial epidermis, mainly associated with the stomata. Starch grain accumulation was more pronounced in the midrib. The cell membranes and chloroplasts were greatly affected by the pollutant. We observed accumulation of phenolic compounds and electron-dense material at the boundaries of the ending veinlets. The microscopic events described precede the appearance of symptoms and are therefore of prognostic value in predicting injury by fluoride and will be useful as biomarkers. The high sensitivity of S. dulcis to fluoride and the specificity of the symptoms confirm, for the first time, in an experiment of active biomonitoring, the potential of this species as a bioindicator.

Six monitoring stations were selected to characterize the variations in airborne concentrations of heavy metals in South Korea between 1999 and 2012. Three stations represented higher concentrations, and three represented lower concentrations. The heavy metals monitored at these stations include cadmium, chromium, copper, iron (Fe), lead, manganese (Mn), and nickel. During the study period, concentrations of heavy metals at many stations, including those around the Seoul metropolitan area, showed a decreasing trend. However, concentrations of Mn and Fe that are primarily of crustal origin increased at four of the six stations. Some stations were significantly affected by emissions from the local industrial complex (IC), and heavy metal concentrations at those stations were relatively high even in summer. Many heavy metal concentrations were higher in spring than in winter, but wintertime concentrations of Cr and Pb were higher at the stations representing lower concentrations due to the dominant influence of combustion emissions. At stations less affected by emissions from the IC, concentrations of Fe and Mn that are predominantly crustal in origin were higher in spring, when Asian dust (AD) events are most frequent. Although Mn concentrations were also high at stations within the steelmaking IC during AD periods, they were much higher during non-AD periods due to local emissions. Variations in heavy metal concentrations, which are heavily influenced by emissions from the IC, warrant individual analysis because their emission characteristics differ from those of typical cases.

The horizons of four natural soils were treated with Cu²⁺ in an acid medium to study the retention capacity of Cu. The possible mineralogical changes arising because of the treatment were also studied. The soil properties and characteristics with the greatest influence on the metal retention and its distribution among the different soil fractions were determined. Crystalline phases of each horizon were determined by X-ray diffraction (XDR). The morphology, structural distribution and particle chemical composition of soil samples were investigated using field emission scanning electron microscopy. Cu distribution in the different geochemical phases of the soil was studied using a sequential extraction. The treatment led to an increase in the amorphous phases and the formation of new crystalline phases, such as rouaite (Cu₂(NO₃)(OH)₃) and nitratine (NaNO₃). Cu was also found superficially sorbed on amorphous hydroxy compounds of Fe that interact with albite, muscovite and gibbsite, and also on spherical and curved particles of aluminium clays. The largest amount of Cu retained was in an exchangeable form, and the smallest amount associated with the crystalline Fe oxides and residual fraction. In the surface horizons, the predominant Cu retention process is complexation in organomineral associations, while in the subsurface horizons it is adsorption.

The choice of plant for phytoremediation success requires knowledge of how plants respond to contaminant exposure, especially their roots which are instrumental in supporting rhizosphere activity. In this study, we investigated the responses of plants with different architectures represented by beetroot (Beta vulgaris), a eudicot with a central taproot and many narrower lateral roots, and tall fescue (Festuca arundinacea), a monocot possessing a mass of threadlike fibrous roots to grow in crude oil-treated sand. In this paper, scanning electron microscopy was used to investigate modifications to plant root structure caused by growth in crude oil-contaminated sand. Root structural disorders were evident and included enhanced thickening in the endodermis, increased width of the root cortical zone and smaller diameter of xylem vessels. Inhibition in the rate of root elongation correlated with the increase in cell wall thickening and was dramatically pronounced in beetroot compared to the roots of treated fescue. The latter possessed significantly fewer (p < 0.001) and significantly shorter (p < 0.001) root hairs compared to control plants. Possibly, root hairs that absorb the hydrophobic contaminants may prevent contaminant absorption into the main root and concomitant axile root thickening by being sloughed off from roots. Tall fescue exhibited greater root morphological adaptability to growth in crude oil-treated sand than beetroot and, thus, a potential for long-term phytoremediation.