During typesetting, the image of figure 4 was also used in figure 5. The mistake was discovered after the original article was published online.

Effects of discharge power, O₂ content, reaction temperature, catalyst introduction, and presence of NO and dichloromethane (DCM) on the formation of nitrogen oxides (N₂O, NO, and NO₂) by discharge in N₂-O₂ mixture have been systematically investigated using a dielectric barrier discharge (DBD) reactor. Results show that discharge in N₂-O₂ mixture always produces several to hundreds ppm of nitrogen oxides as byproducts. The production of nitrogen oxides increases with the increase of O₂ content and the introduction of Al₂O₃ or RuO₂/Al₂O₃ catalyst. N₂O production first increases and then decreases/levels off with increasing discharge power at room temperature, but increases monotonously at 300 °C. NO and NO₂ are produced only at relatively high discharge power at room temperature but are produced at all discharge power tested at 300 °C. Increasing the reaction temperature from room temperature to 300 °C significantly reduces the production of N₂O but increases that of NO and NO₂. The presence of hundreds ppm NO in N₂-O₂ mixture significantly reduces the production of N₂O due to the effective quenching of the vital species for N₂O formation (N₂(A³Σᵤ⁺)) by NO. The presence of hundreds ppm DCM, however, hardly affects the production of nitrogen oxides, demonstrating the precedence of nitrogen oxide production over DCM decomposition in N₂-O₂ plasma.

The aim of the study was to determine polycyclic aromatic hydrocarbon (PAH) content in different forest humus types. The investigation was carried out in Chrzanów Forest District in southern Poland. Twenty research plots with different humus types (mor and mull) were selected. The samples for analysis were taken after litter horizons removing from a depth of 0–10 cm (from the Of- and Oh-horizon total or A-horizon). pH, organic carbon and total nitrogen content, base cations, acidity, and heavy metal content were determined. In the natural moisture state, the activity of dehydrogenase was determined. The study included the determination of PAH content. The conducted research confirms strong contamination of study soil by PAHs and heavy metals. Our experiment provided evidence that different forest humus types accumulate different PAH amounts. The highest content of PAHs and heavy metals was recorded in mor humus type. The content of PAHs in forest humus horizon depends on the content and quality of soil organic matter. Weaker degradation of hydrocarbons is associated with lower biological activity of soils. The mull humus type showed lower content of PAHs and at the same time the highest biological activity confirmed by high dehydrogenase activity.

Photosynthetic microalgal growth is a promising tool for mitigation of gaseous effluent from the cement production, which is highly implicated in global warming and climate change. We investigated the effects of actual cement industry flue gas on the physiology of Chlorella vulgaris under laboratory-controlled conditions. We evaluated the growth, photosynthetic performance, intracellular metal content, total proteins, and carbohydrates of C. vulgaris under three gas input rates: 9, 36, and 54 L d⁻¹; compressed air (54 L d⁻¹) was used as control. The results showed no correlation between the flue gas input rates on total proteins and carbohydrates in the algal biomass, and no effects on growth rates. However, rapid light curves indicated that the light use efficiency (α) and the maximum relative electron transport rate (rETRₘₐₓ) were stimulated when applying 9 and 36 L d⁻¹. Metal analysis revealed an accumulation of Cr, Zn, and Ni in the algal biomass exposed to flue gas (54 L d⁻¹) compared to the control. Thermogravimetry and differential thermal analysis showed that 70% of the cement kiln dust were composed by uncalcined limestone, which may have stimulated photosynthesis, as indicated by the rapid light curve parameters. In general, C. vulgaris can be considered a robust organism for cement flue gas bioremediation.

In this study, biochar produced by pyrolysis of urban pruning wood (Bpw) and sewage sludge (Bss) were characterized and investigated as adsorbents for the removal of Cu(II), Pb(II), Zn(II), and As(V) from contaminated solutions. Both types of biochars showed different physical-chemical properties and metal(loid) content. In Bss, Cu, Zn, and Pb concentrations exceeded the upper limit of the common ranges in soils. However, when they were tested for their effect on soil invertebrates, neither of the biochar was expected to exert negative effects as long as the dose applied as an amendment was ≤ 4.8 t ha⁻¹. For an assessment of the effectiveness of biochar in the immobilization of metal(loid)s, three contaminated solutions with acidic pH and different pollutant concentrations were added to both types of biochar. Precipitation as oxy-hydroxides and the formation of complexes with active functional groups of the organic matter were the main mechanisms of metal(loid) fixation by the biochar, with increased precipitation and a rising pH. Both types of biochar were effective at immobilizing Pb and Cu, while Zn showed less effectiveness in this regard and As the least. The high P content of the biochar from sewage sludge favored Pb fixation, presumably forming complexes with phosphates, while competition between phosphate and arsenate ions decreased As adsorption by Fe compounds. The metal(loid)s immobilized by biochar from urban pruning wood were more bioavailable than those fixed by biochar from sewage sludge.

17α-Ethinylestradiol (EE2), diclofenac (DCF), and 4-nonylphenol (4NP) belong to the most common micropollutants (MPs) occurring in municipal wastewater treatment plants (WWTPs). The WWTPs are the primary barrier against the spread of micropollutants in the environment. The aim of this work was to study the kinetics of biological removal of the three aforementioned micropollutants from wastewater and to check whether the acclimation of biomass influenced on the kinetic parameters. In addition, the effect of MPs on the biochemical activity of microorganisms was tested. DCF inhibited the respiration activity of biomass to the highest extent, followed by 4NP and EE2, respectively. DCF occurred to be less susceptible to microbial decomposition than the other two MPs and was removed from wastewater at the lowest degree of 58%. The degrees of removal of EE2 and 4NP were higher than that of DCF and equal to 93 and 71%, respectively. The kinetic parameters determined in this work can be used in modelling and simulation of the removal of micropollutants from wastewater. They improve the predictive ability of the biokinetic models. The acclimation of the biomass to the relevant micropollutant does not influence on the kinetic parameters of biomass growth; however, it causes the increase of the yield coefficient for heterotrophic biomass.

Intercropping of arsenic (As) hyperaccumulator Pteris vittata and cash crop Morus alba could improve the As concentration in the hyperaccumulator but decrease As concentration in the intercropped crop. The effects of several amendments on the transfer of As were investigated to determine an enhancement strategy for the intercropping system of P. vittata and M. alba. Phosphorus, in the form of Ca(H₂PO₄)₂, promoted the release of As to the soil solution and apparently increased the As removal from the soil by 42% compared with the untreated variant. The addition of FeSO₄ and CaCO₃ decreased As concentration in the soil solution and the uptake of As by both plant species. The As levels in the mulberry leaves remained under the threshold limits of feedstuffs in China. Intercropping was confirmed as an applicable strategy to manage contaminated soil. Hence, under the condition that all treatments produced safe mulberry leaves, Ca(H₂PO₄)₂ was the appropriate amendment to achieve the highest As removal rate, whereas FeSO₄ could lower the risk of As to further migrate to another medium.

This study presents a combination of dispersive liquid-liquid-solidified floating organic drop microextraction (DLLSFODM) and slotted quartz tube (SQT) with conventional flame atomic absorption spectrometry (FAAS) to improve the sensitivity for cadmium determination. A ligand namely 2-(4-methylphenyl)-1H-imidazo-[4,5-f]-[1,10]-phenanthroline which has not been used in trace analyte determination was used to form a cadmium complex. Stepwise optimization of parameters affecting complex formation (pH, ligand, and buffer solution) and extraction (extraction and dispersive solvents, salt effect and mixing) was done to maximize cadmium absorbance. The slotted quartz tube was fitted onto the flame burner and optimized to increase residence time of atoms in the flame. Instrumental parameters such as sample and fuel flow rate were also optimized to further enhance the absorbance signal for cadmium. Using optimal parameters and values, the limits of detection and quantification were determined to be 0.81 and 2.69 μg L⁻¹, respectively. Low percent relative standard deviations (< 6.0%) indicated good precision for both extraction and instrumental measurements. Recovery tests were used to determine the accuracy of the method and the recovery results obtained were between 88 and 113%. Graphical Abstract ᅟ

This paper describes catchment processes that favor the trophic instability of a shallow polymictic lake, in which a shift from eutrophy to hypertrophy occurs rapidly. In the lake, in 2007, the winter discharge maximum and an intensive precipitation (monthly sums exceeded 60 mm) in a vegetation season were observed. In 2007, the cyanobacterial blooms disappeared and the water trophy decreased. Total phosphorus (TP) was the main factor determining the high trophic status of the lake. The TP retention resulted from a quick flow of two inflows: QI1 (r = 0.64) and QI2 (0.56), and the base flow of tributary 1 (0.62). A significant negative correlation between TP and precipitation (r = − 0.54) was observed. Both the surface and the groundwater inflow of I4 showed a positive correlation with the retention of PO₄ (r = 0.67 and r = 0.60, respectively), whereas the outlet discharge determined RNO₃ (r = 0.57). The trophy of Lake Syczyńskie was determined by the relationship between nutrient input and export, expressed as the ionic retention, Carlson’s trophic state index (TSI), and phytoplankton abundance. The results showed that many factors influence the stability of water quality in small, polymictic lakes. However, in the studied lake, intense precipitation and winter discharge maxima (particularly base flow) prevented summer cyanobacterial blooms.

The emissions of ammonia (NH₃) from soil have accelerated rapidly and have affected both vegetation and the atmosphere. It is thus necessary to investigate not only the amounts of NH₃ gas released from the soil surface but also the dynamics of NH₃ gas in the soil. Active sampling and diffusive sampling have been adopted to measure the components of soil air. However, gas aspiration for active sampling inevitably collects a wide range of soil gases. We examined the application of passive sampling to NH₃ gas measurements in soil and compared the outcome to active sampling results. In laboratory experiments, the performance of the present passive sampler in moist soil was investigated. When immersed in solution, the passive sampler collected gas released from the solution, depending on the vapor pressure of the volatile substance. In laboratory experiments measuring NH₃ gas in soil, there were no significant differences among the values measured by passive sampler at each measurement point. Thus, we concluded that the passive sampler can accurately measure NH₃ gas in soil. In field experiments, the average NH₃ gas concentrations were 43 ppb in urea-added soil and 1 ppb in control soil. The relative standard deviation of NH₃ concentrations in urea-added soil was large. This result is expected because soil characteristics can change under the influence of ambient environmental factors such as wind, rain, and temperature. In other words, the spatial differences in NH₃ emissions were reflected in the passive sampler measurements.