The sorption and desorption processes of Se(VI) onto non-living Eichhornia crassipes (E. crassipes) and Lemna minor (L. minor) were evaluated. Different pH values of the initial Se solution (20 μg L⁻¹) were tested at static conditions. At dynamic conditions of horizontal flow, biomass-packed columns (BPC) were estimated as prepared (pH 4) and unprepared (pH 6–7) and at different flow rates. The desorption process was tested using HCl (0.1 M) as the eluent. The maximum Se uptake took place at a pH of 4 for both biomasses. The lowest flow rate improves major Se removal due to the increase in contact time. The Se was desorbed from the biomass with elution efficiencies of 5 and 18 % for E. crassipes and L. minor, respectively. Nevertheless, more time was needed to increase these efficiencies and reach desaturation times. The breakthrough curves showed that unprepared E. crassipes and L. minor BPC at horizontal flow, with a flow rate of 6 and 4 mL min⁻¹ respectively, had a biomass removal capacity of 0.135 and 0.743 μg g⁻¹ correspondingly. The system of E. crassipes is more efficient, suggesting an ion exchange sorption mechanism. This demonstrates that non-living E. crassipes and L. minor have the capacity to remove Se from very dilute solutions.

Arbuscular mycorrhizal fungi (AMF) hold a crucial role in ecosystems because they are involved in nutrient cycling between soil and plants. This work aimed at evaluating the impacts that atmospheric pollution by polycyclic aromatic hydrocarbons may have on infectivity of indigenous AMF in soils. Two agricultural soils (Maconcourt, La Bouzule) were exposed for 2 weeks to ambient air (control, C) or to atmospheric phenanthrene (PHE) deposition (180 μg m−3 air). After exposure, soils were divided into a top (0–1 cm) and a bottom (1–15 cm) layer fraction. AMF infectivities of soils were determined after 2 weeks of atmospheric exposition using leek (Allium porum) as bioassay plant. Atmospheric PHE was mainly recovered in the top layer of soil (500–1,350 μg kg−1) of both soils and did not readily diffuse into the depth. Atmospheric contamination led to decreases in AMF infectivities of the top layer in both soils and affected the growth of leeks. Our results not only report evidence that infectivity of indigenous AMF is sensitive to PHE in soils but also emphasize that AMF are primary affected by the soil layer regardless to the pollution level.

Air pollution emissions were not continually monitored in the Upper Silesian Industrial District (USID), southern Poland, and data is only available for the last 20 years. Long-lasting and severe tree ring reductions in pines growing 5–20 km north of the USID area recorded particularly high levels of air pollution emissions in the period 1950–1990. Especially high amounts of reductions and many missing rings were found in the period 1964–1981. At the same time, pines growing 60 km west of the USID do not record deep ring reductions; this proves that the phenomenon is of a regional nature. Increases in infant mortality and lung, bronchial, and tracheal cancer morbidity rates among males were also recorded in the USID during periods of high air pollution. Infant mortality rates increased several years after the tree ring reductions. Therefore, it may be possible to use tree ring reductions as an early indicator of the occurrence of adverse effects on human health.

Nanoparticles (NPs) are emerging as a new type of contaminant in water and wastewater. The fate of titanium dioxide nanoparticles (TiO₂NPs) in a granular activated carbon (GAC) adsorber and their impact on the removal of trichloroethylene (TCE) was investigated. Key parameters governing the TiO₂NP–GAC interaction such as specific surface area (SSA), zeta potential, and the TiO₂NP particle size distribution (PSD) were determined. The impact of TiO₂NPs on TCE adsorption on GAC was tested by conducting TCE adsorption isotherm, kinetic, and column breakthrough studies in the presence and absence of TiO₂NPs. SSA and pore size distribution of the virgin and spent GAC were obtained. The fate and transport of the TiO₂NPs in the GAC fixed bed and their impact on TCE adsorption were found to be a function of their zeta potential, concentration, PSD, and the nature of their aggregation. The TiO₂NPs under investigation are not stable in water and rapidly form larger aggregates. Due to the fast adsorption kinetics of TCE, the isotherm and kinetic studies found no effect from TiO₂NPs. However, TiO₂NPs attached to GAC and led to a reduction in the amount of TCE adsorbed during the breakthrough experiments suggesting a preloading pore blockage phenomenon. The analysis of the used GAC confirmed the pore blockage and SSA reduction.

Titanium dioxide (TiO2)–silicon dioxide (SiO2) thin films were synthesized using the peroxo titanic acid approach (PTA) combined with the sol–gel method at low temperature around 100°C. The effects of type and amount of dopants of ferric (Fe3+) or thiourea (N-S) and co-dopants of Fe3+ and N-S on the films physicochemical properties and on the photocatalytic degradation of the methylene blue and formaldehyde under UV and visible light irradiation were investigated. Physicochemical properties of photocatalysts were characterized by X-ray diffraction, transmission electron microscopy, wavelength-dispersive X-ray fluorescence spectrometry, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and UV–Vis spectroscopy. The results showed that the TiO2 crystal phases obtained from this method were exclusively anatase and the needle-like crystals have an average diameter of 10–25 nm. Compared with the single dopant of 1.0 wt.% Fe3+ or 0.125 wt.% N-S that was the optimal concentration for photocatalytic degradation of methylene blue and formaldehyde, the co-dopants of 0.125 wt.% N-S + 1.0 wt.% Fe3+ furthermore increased the degradation efficiency. Co-dopants of 0.125 wt.% N-S + 1.0 wt.% Fe3+ in TiO2–SiO2 films were considered to play synergistic roles in narrowing TiO2 band gap resulting in the higher methylene blue and formaldehyde degradation efficiency. Since the crystal grain size of TiO2–SiO2 films synthesized by the PTA method is small, in the visible light region, the high transmittance was attainable to 80% with no-doped and dropped to 50–60% with doped thin films.

Perchlorate (ClO 4 − ), a thyroid hormone disruptor, is both naturally occurring and a man-made contaminant increasingly found in a variety of terrestrial environments. The environmental presence of ClO 4 − is considered to be the result of atmospheric formation and deposition processes. The ultimate processes, particularly heterogeneous-based reactions, leading to natural ClO 4 − formation are not well understood. Oxidation of chlorine species by an energetic source such as lightning is considered to be one of the potential heterogeneous sources of natural ClO 4 − . Currently, there is very little information available on lightning-induced ClO 4 − . We designed a laboratory electrical discharge reactor capable of evaluating ClO 4 − formation by the oxidation of “dry” sodium chloride (NaCl) aerosols (relative humidity (RH) <70%) in electrical discharge plasma at voltages and energies up to 24 kV and 21 kJ, respectively. Similar to other non-electrochemical ClO 4 − production processes, the amount of ClO 4 − produced (0.5–4.8 μg) was 3 orders of magnitude lower than the input Cl− (7.1–60.1 mg). The amount of ClO 4 − generated increased with peak voltage (V) and theoretical maximum discharge energy with ΔClO 4 − /ΔV = 0.28 × 10−3 μg V−1 (R 2 = 0.94) and ΔClO 4 − /ΔE = 0.44 × 10−3 μg J−1 (R 2 = 0.83). The total ClO 4 − generated decreased with an increase in relative humidity from 2.8 ± 0.1 μg (RH ∼46%) to 0.9 ± 0.1 μg (RH ∼62%) indicating that the presence of moisture inhibits the formation of ClO 4 − . Additional modifications to the reactor support the hypothesis of ClO 4 − formation due to the action of plasma on Cl− aerosols as opposed to direct oxidation on the surface of the electrodes. Finally, the contribution of lightning-induced ClO 4 − in North America is calculated to have a wide range from 0.006 × 105 to 5 × 105 kg/year and is within the range of the measured ClO 4 − depositional flux in precipitation samples obtained across the USA (0.09 × 105–1.2 × 105 kg/y).

Principal component analysis has been used as a tool for the detection of potentially outlying observations in multivariate data sets of polycyclic aromatic hydrocarbon concentrations (PAHs) in ambient air. The outlier statistic developed is the vector distance of each observation at a given site from the origin of principal component space. It is shown that the success of this technique relies on the usually very strong correlation of concentrations of different PAHs in ambient air, such that any deviation from this correlation is noteworthy. Indeed, it is so strong that the first principal component has been omitted from the technique since it is related mostly to absolute concentration. The method has been successful in detecting observations with unusually high concentrations of one or more PAHs. Moreover, it has been possible to identify periods where the UK pollution climate was abnormal during periods of extreme weather. Advice and guidance for the practical use of the technique is also given.

The relationships between the Ni concentrations of the mudflat snails Telescopium telescopium and the surface sediments have not been reported yet from tropical intertidal areas. In this study, telescope snails and surface sediments were collected from 18 geographical sampling sites in intertidal areas of Peninsular Malaysia. The concentrations of Ni were measured in seven different soft tissues of the snails namely foot, cephalic tentacles, mantle, muscle, gill, digestive cecum, and remaining soft tissues. It was found that different concentrations of Ni were found in the different soft tissues, indicating different mechanisms of sequestration and regulation of Ni in these different tissues. By comparing the Ni concentrations in the similar tissues, spatial variations of Ni were found in the different sampling sites although there was no consistent pattern of Ni in these sites. The highest Ni variation based on the ratio of maximum to minimum values indicated that cephalic tentacle and foot were the main organs having high Ni variation. The use of correlation analysis and multiple linear stepwise regression analysis revealed that digestive cecum of T. telescopium could be used to reflect the Ni contamination of the sampling site. Also, the digestive cecum and gill were found to be the main bioaccumulation and storage sites for Ni. From the Ni accumulation patterns in all the populations investigated, tissue redistributions of Ni in gill was identified and could be proposed as an indicator of high Ni bioavailability and contamination in the sampling site. To our knowledge, this is the first and most comprehensive study on Ni accumulation in the different soft tissues of T. telescopium from tropical intertidal areas, in relation to the sediment data.

The effect of different humic fractions on polychlorinated biphenyl (PCB) contamination in soils was tested in the field by means of 53 soil samples from a high-altitude grassland plateau in the Italian Alps. Three humic fractions (humin, humic acids, and fulvic acids) were characterized in parallel by quantifying 12 PCB congeners to establish a direct relationship between PCB levels and humic fraction concentrations. Humin (the most hydrophobic fraction) appears to be the most closely correlated with the amount of PCBs in soil (R ²â€‰= 0.83), while fulvic acid shows the lowest correlation (R ²â€‰= 0.49). The idea of preferential sorption of hydrophobic compounds in the humin fraction is discussed, and the humin carbon content (f ₕᵤₘᵢₙC) is proposed as an improved parameter for evaluating the potential for POP accumulation in soils, replacing total organic carbon (f ₒc). Congener studies revealed that penta- and hexa-substituted-CBs show the optimal combination of physicochemical properties for equilibrating with the humin content in soil. Moreover, f ₕᵤₘᵢₙC/f ₒc is conceptually equivalent to the empirical coefficients used in predictive K ₛₐ equations. In our samples, the f ₕᵤₘᵢₙC/f ₒc was 0.55, a value in between the empirical coefficients proposed in the literature. In predictive equations, the use of f ₕᵤₘᵢₙC instead f ₒc avoids the necessity of using an empirical parameter for a ‘generic’ condition by introducing an experimental parameter (f ₕᵤₘᵢₙC) that takes into account local conditions (organic matter composition).

Over the last decades, removal of potentially toxic and hazardous materials has received a great deal of attention in the field of environmental pollution. Problems associated with the disposal of the wastes of different kinds of industries led to studies of the sorption–uptake properties of clay minerals and zeolites. In the present research, the behavior of vermiculite particles ranging between 425 and 500 μm in a laboratory-scale fluidized bed column for uptake of Cs, Hg, and Mn ions from aqueous solutions and wastes in the presence of competing cations has been studied in order to investigate techniques for decontamination of liquid phases. Vermiculite selectively removed high percentages of Cs even from low concentrations in the presence of competing cations. Also removed were up to 60 % of added Hg²⁺ at concentrations of 5 ppm from drinking water and about 84 % from seawater, and furthermore, Mn²⁺ was selectively removed from low-concentration (ca 10 ppm) industrial wastes even when the ratio of Mn²⁺ to competing cations was 1:94. The results suggest the potential use of vermiculite as decontaminating agent in well-designed fluidized bed columns.