Fungus Pleurotus ostreatus HAAS can tolerate and remove heavy metals from water. Among three heavy metals tested, the removal of Pb was the most efficient (99.9–100.0%), followed by Cd (45.9–61.1%), and Cr (29.4–64.5%). The uptake of heavy metals by the fungus varied and was dependent on the element. Pb was found to be transported primarily into the fungal cell wall (68.2–91.2% of the total), which was much higher than the insoluble form (20.1–32.7%), and the maximum intracellular concentration of Pb was found to be 119,830.4 mg kg⁻¹. In the cases of Cd and Cr, their insoluble forms were the main products of the reaction with the fungus, which accounted for 30.0–39.1 and 19.6–37.4% of the total. P. ostreatus HAAS produces oxalic acid, and this production is stimulated by Pb and Cr but inhibited by Cd. Parallel experimental results indicated that the concentration of the soluble metals in solution decreased with the increase of oxalic acid, which further suggested that oxalic acid played a partial role in the removal of the soluble heavy metals by chelation. These results revealed that this species of fungus has a variety of response mechanisms to the presence of heavy metals in solution.

Nitrogen recovery and valorization is gaining interest due to the current need for nitrogen removal, so it is of great interest that ammonium-selective sorbents be evaluated. In this study, a zeolitic material synthesized from coal fly ash (Ze–Na) in sodium form as well as its modification to potassium form (Ze–K) were evaluated as sorbent materials for the recovery of ammonium from wastewater effluents. The sorption performance was assessed through three consecutive sorption-desorption cycles reporting opposite behavior in terms of ammonium sorption capacity. Decreasing in the case of Ze–Na and to slightly increase for Ze–K due to alkaline activation of zeolite surface. The maximum sorption capacities obtained were 109 ± 4 mg NH₄/g and 33 ± 1 mg NH₄/g for Ze–Na and Ze–K, respectively. It is important to point out that in the case of Ze–Na, the maximum sorbent capacity was obtained during the first sorption cycle whereas in the case of Ze–K, it was obtained during the last working cycle due to the alkaline regeneration. Kinetic studies showed that after every regeneration step, the sorption kinetics turn faster as alkaline desorption increased the zeolite-specific surface, thus increasing the size of porous and enhancing the diffusion through the particle. Results obtained indicate that sorption capacity decreased significantly after every working cycle using Ze–Na whereas Ze–K followed the opposite behavior despite its initial lower sorption capacity.

A vermifilter (with earthworms, VF), with a conventional biofilter (no earthworms, BF) as a control, was established to examine the survival state and adaptability of earthworms in protein perspective. The VF behaved with a significantly higher organic matter decomposition and lower sludge yield due to the presence of earthworms. However, during the steady stage (12 months), the earthworm biomass decreased slightly from 32.0 to 24.2 g/L, while the earthworm average weight increased, indicating that the earthworm suffered some adverse effects from the VF. Notably, from the perspective of the earthworm protein, the earthworms showed a higher Shannon-Weaver index (from H = 2.76 to 3.06) than the BF and up-regulated some proteins to cope with the negative effects from the VF. These up-regulated differential proteins played a variety of crucial roles in many cellular processes. The results suggested that a more specialized and stable protein expression of earthworms was developed in the VF, reflecting the adaptabilities of the earthworms in the VF.

In industry areas of Poland such as Silesia or urban sites like Krakow and some other cities, the levels of pollutants frequently breach air quality standards. Particulate matter (PM) is the most important constituent of atmospheric pollution. Beginning on 1st February 2014 until 31st January 2015, the samples of fine particulate matter PM₂.₅ (aerodynamic diameter of particles less than or equal to 2.5 μm) were collected at a site in the south-eastern Krakow urban background area. During this period, 194 samples were taken. The samples showed daily variation of PM₂.₅ concentration. From these data, monthly variations were estimated and presented in this paper. Monthly integrated data are more representative for the Krakow urban background and show seasonal variation of PM₂.₅ pollution. The lowest monthly concentration value was found for August 2014—about 10 μg m⁻³, the highest for February 2014–70 μg m⁻³, whereas the average annual value was about 31 μg/m³. Utilizing X-ray fluorescence method, concentrations of 15 elements for each sample were determined and 8 inorganic ions were analyzed by ion chromatography. Additionally, the samples were analyzed for black carbon (BC). Receptor model PMF (positive matrix factorization) was used for source identification and apportionment. The modeling identified six sources and their quantitative contributions to PM₂.₅ total mass. The following sources were identified: combustion, secondary nitrate and sulfate, biomass burning, industry or/and soil and traffic. Finally, monthly variations of each source are presented.

In this study, the sorption characteristics of U(VI) onto eucalyptus biochar as a function of various operating parameters such as solution pH, initial metal ion concentration, contact time and ionic strength of the medium are reported. Biochar was characterised using various techniques such as CHNS element analysis, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). SEM analysis showed the presence of micro- and macropores in the sorbent, and FTIR spectra confirmed the presence of functional groups like carboxylic (−COOH), hydroxyls(−OH), carbonyls(–C=O), etc. Maximum sorption of about 95% is found to occur in the pH range of 5 to 6. U(VI) sorption onto biochar reached equilibrium within 20 min at pH 5.5. The kinetic data were analysed using both pseudo-first-order and pseudo-second-order kinetic models, and the latter is found to be more appropriate to explain the observed kinetics. The equilibrium data were correlated with Langmuir and Freundlich models, and the maximum monolayer adsorption capacity obtained from the Langmuir model was 27.2 mg/g at 293 K. From EDS, FTIR and XPS measurements, it is found that the sorption process involves chemical interaction between the U(VI) and the surface functional groups on the adsorbent. Efficient removal of low level of uranium from ammonium diuranate supernatant demonstrates its utility as sorbent for waste water treatment.

This study aimed to investigate the potency of soil reflectance spectroscopy in the visible and near infrared (Vis-NIR) spectral regions in estimating soil heavy metal pollution in the western coastal front of Thessaloniki (N. Greece) and how the protocol used for chemical analyses can affect the models’ performance. For this purpose, 49 topsoil samples were collected and the concentrations of Cd, Cr, Cu, and Pb were determined by two different analytical methods, i.e., ISO 11466 based on the technique of atomic absorbance spectrometry (AAS) and ISO 14869-1 using the technique of inductively coupled plasma-atomic emission spectrometry (ICP-AES). The spectral signatures were applied for modeling the metal concentrations by using the partial least squares regression (PLSR) method. To eliminate the “noise” of data and enhance the models’ accuracy, four spectral pre-treatment methods were used. The overall results showed that there is heavy metal pollution in the soils of specific areas in the studied region and that the use of different chemical analytical methods can affect the performance of examined prediction models. Better prediction models were created for the cases of Pb, Cu, and Cr concentrations, which were estimated by the application of ISO 14869-1, while for the case of Cd better prediction models were obtained, by the application of ISO 11466. These results may indicate that soil reflectance spectroscopy can measure the total heavy metal content in soil samples.

Acid deposition and temperature variation could lead to changes of physiological characteristics of plants in response to stress. In this paper, Medicago sativa CV. Dongmu–1 was investigated to test the effects of freeze-thaw circle and acid deposition upon the changes of osmotic adjustment substances, biological membrane permeability, and antioxidant enzymes. The experiment was conducted under laboratory conditions, and the seedlings were divided into four groups (group I: no treatment, group II: acid stressed only, group III: freeze-thaw stressed only, group IV: both freeze-thaw and acid stressed). Results indicated that under freeze-thaw circle and acid deposition, the contents of malondialdehyde (MDA) and proline increased respectively by 0.6~203.4 and 19.3~68.8% when compared with group I, while protein content declined by 4.1~31.7%, and the effects were even significant than freeze-thaw-only stressed groups. In the freeze-thaw process, superoxide dismutase (SOD) activity dropped at first and then increased with the increase of temperature, peaking at − 3 °C by 1118.45 U g⁻¹; peroxidase (POD) activity showed a brief rise and declined rapidly below 0 °C. By increasing the potentials of antioxidant enzymes and MDA, the membrane lipid peroxidation inside alfalfa was prevented; meanwhile, several indexes changed adaptively in resisting hurts. Variation of SOD and POD was induced by the defense mechanism, which showed alfalfa’s satisfactory cold resistance and acid tolerance. Further research on acid deposition and freeze-thaw circle would be beneficial for the global cultivation of forage grass.

Due to intensive agricultural activities to meet the growing needs for food, large volumes of water are consumed and an increasing amount of agrochemicals are released into the environment threatening the aquatic ecosystem. In order to ensure a sustainable agricultural management, it is crucial to develop an integrated water assessment plan that includes not only water quantity and quality but also toxicological assessments. The Pergamino River basin (province of Buenos Aires, Argentina) was selected as a representative case of study to monitor and assess the impact of both the long-term intensification of soybean production and fast-growing urban development on surface and groundwater sources. Physicochemical analyses and a Water Quality Index were determined and showed that water quality falls into the marginal category, compromising the irrigation purposes and threatening aquatic life. Glyphosate and aminomethylphosphonic acid were detected at least once in all sites. Caenorhabditis elegans toxic bioassays were performed and a toxicological ranking was developed. This analysis proved to be useful to detect toxicity even when water parameters met regulatory requirements and water quality seemed to be satisfactory. This research constitutes a valuable model to be replicated in other river basins that have been impacted by intensive agriculture and growing urban development in order to assess water quality conditions and ensure sound water resources management.

Reduced graphene oxide (RGO) and titanium dioxide (TiO₂) nanoparticles were immobilized on cotton textile substrates to produce self-cleaning textiles. Varying number of layers of RGO and TiO₂ nanoparticles were coated by a facile method, and their photocatalytic potential was evaluated by measuring the degradation rate of rhodamine B (Rh-B) in an aqueous solution in a photoreactor under simulated solar irradiation. X-ray diffraction (XRD) and zeta potential measurements of starting materials were studied as they are crucial for innovative methods of functionalization. The study confirms that it is possible to ensure a good adhesion of nanoparticles on textile samples without the use of a resin. The application of varying number of RGO and TiO₂ coatings has influence on photocatalytic properties of functionalized cotton textile substrates. The energy band gap of the samples reduces from 3.25 to −3.20 eV with the number of RGO coatings. All five de-ethylated intermediates of Rh-B during the photocatalytic degradation were identified using a high-performance liquid chromatography–mass spectrometry method. The experimental results show that, in general, the higher the number of RGO coatings is, the higher the photocatalytic efficiency (η) of the functionalized substrate is (η=87% for three RGO coatings on TiO₂).

Bodies of water contaminated by cyanobacteria and their neuro- and hepatotoxins have caused environmental and public health issues all over the world. Therefore, determining safe concentrations in water for multiple uses to protect aquatic biota and identify forms of remediation are of broad interest. In this study, we isolated strains of the cyanobacteria Microcystis aeruginosa and Cylindrospermopsis raciborskii, which produce microcystin (MC) and saxitoxin (STX), respectively. Ecotoxicological tests using suspensions of lysed lyophilizated cells with concentrations of toxins equivalent to those permitted by legislation for potability (1 μg L⁻¹ for MC and 3 μg L⁻¹ for STX) did not result in significant mortality of the model organism, Ceriodaphnia dubia, where as concentrations five times greater resulted in decreased survival for both toxins. However, reproduction was significantly reduced even in the lower concentrations, indicating that the currently permitted standards are not safe for environmental protection. When cyanotoxins were treated with ultrasound, mortalities were no longer significant, independent of concentrations. Although reproduction was still lower in relation to the control, it was significantly higher when compared to the results obtained before ultrasound. Ultrasound has been previously applied to cyanobacteria cell lysis, but this is the first study to investigate the ecotoxicological effects of ultrasound on cyanotoxins. Using new test organisms and different times and potency of sonication will permit the development of more efficient techniques for the remediation of these toxins and the development of more adequate parameters for the protection of aquatic life.