Chemosphere最新文献

Coal fly ash (CFA), a metal-rich byproduct of coal combustion is produced in vast quantities and poses significant ecological risks. CFA also contains abundant technologically relevant metal oxides and trace metals, including rare earth elements (REE), often at higher concentrations than in primary ores. This makes sustainable recovery strategies a major industrial opportunity. Here, green solvent systems were applied to leach metals from CFA, and the resulting leachates were added to cultures of Magnetospirillum gryphiswaldense (MSR1), a model magnetotactic bacterium that biomineralizes iron into membrane-bound magnetic nanoparticles (magnetosomes) and is capable of interacting with non-iron metals through adsorption and biomineralization. Eleven green solvents, including deep eutectic solvents (DES), were tested for extraction efficiency, with six showing performance comparable to a mineral acid control. Copper (Cu) emerged as the primary toxicant to MSR1, prompting selective precipitation with potassium ferrocyanide trihydrate (PFCT) to reduce its concentration. Cu-depleted lactic acid-based leachates supported MSR1 growth and magnetosome formation even without supplemented iron. Nano-XRF and ICP-MS analysis revealed MSR1 interacts with CFA-derived metals, most significantly showing that produced CFA magnetosomes contained a 5.3-6.1-fold increase in Cu compared to controls. As Cu is both a growth inhibitor and a target pollutant, these findings suggest MSR1 may bioaccumulate Cu within magnetosomes as a detoxification strategy. Overall, this study demonstrates a combined chemical-biological route for CFA valorisation, enabling recovery of diverse metals from waste while producing magnetosomes with distinct compositions.

Due to human exposure and environmental risks, per- and polyfluoroalkyl substances (PFASs) in commercial products are subject to increasingly stringent and worldwide regulations. In this study, impregnation products (n = 25), textiles (n = 15) and food contact materials (n = 18), mainly from the Swiss market, were selected for their water- or grease-proof capabilities and assessed for the presence of PFASs. Total fluorine was detected in 52 % of impregnation products, 87 % of textiles, and 61 % of food contact materials by combustion ion chromatography. A targeted analysis of perfluoroalkyl carboxylic acids (PFCAs), sulfonic acids (PFSAs), and fluorotelomer sulfonates (FTSs) resulted in individual PFASs concentrations that were all below 165 ppb. The application of a modified total oxydizable precursor (TOP) assay to the samples enabled the transformation of oxidizable precursors, including side-chain fluorinated polymers, into PFCAs, with average increases in concentrations of the targeted PFASs in fluorine equivalents by a factor of 23 600 for impregnation products, 1300 for textiles, and 420 for food contact materials. The PFCA fingerprints were dominated by short C₆ chains, which are currently being restricted by national and international regulations. In this context, applying the TOP assay uncovered a significant proportion of samples with precursors providing perfluorohexanoic acid (PFHxA) concentrations above the 1000 ppb threshold, compared to a direct PFASs targeted approach. While providing a snapshot of the current market situation, this study demonstrates the usefulness of a TOP assay for enforcing regulatory compliance. It also highlights the prevalence of short-chain PFASs in commercial products despite the availability of fluorine-free alternatives.

Absorption, fluorescence and cathodoluminescence methods were used to study the transformation of chloramphenicol in water. The Folin-Ciocalteu reagent method was used to determine the total phenolic content (TPC) after the transformation of the antibiotic. New experimental data were obtained on the TPC reduction after the transformation of chloramphenicol in water under the action of UV sources (KrCl, XeBr, XeCl, Xe₂ excilamps and a UVb-04 bactericidal irradiator) and an e-beam. Using HPLC-MS, 5 final products of the antibiotic transformation were found after 1600 pulses of e-beam exposure. After UV irradiation, accumulation of two final photoproducts fluorescing in the region of 350 nm and 430-450 nm was recorded. It was found that the conversion of chloramphenicol in water under the action of an e-beam (when the pulse duration of 2 ns, numbers of pulses from 50 to 3200, an average electron energy of 170 keV, a current density of 130 A/cm², a pulse energy density of 44.2 mJ/cm², and a pulse repetition rate of 1 Hz) was 98.2 %. TPCs in an aqueous solution of chloramphenicol were 23.33 ± 1.63 and 20.19 ± 1.41 mg GAE/g after irradiation with a Xe₂ and the е-beam, respectively. The TPC in aqueous chloramphenicol solution remained stable high at 163.86 ± 11.47 mg GAE/g after exposure to KrCl excilamp irradiation. According to the absorption and fluorescence spectra, it was found that the products of chloramphenicol transformation in water under exposure to e-beam irradiation were minimal, compared to UV irradiation. The obtained data are important for further understanding of the pathways of chloramphenicol transformation affected by the artificial UV and e-beam radiation.

The pervasive presence and detrimental impact of microplastics (μPs) on the ecosystem necessitates the development of effective remediation strategies. As potential adsorbents for μPs, we present a strategy utilizing metal oxide nanoparticles and cellulose nanomaterials. A nanocellulosic matrix was prepared by processing microfibrillated cellulose (MFC) and (2,2,6,6-Tetramethylpiperidin-1-yl)oxyl (TEMPO)-oxidized cellulose nanofibers (T-CNF). Magnetic nanocellulose sponges (NCs) embedding Fe₃O₄-TiO₂ nanoparticles into this matrix were prepared using a simple freeze-drying technique. The prepared NCs were modified with hexadecylphosphonic acid (HPA) to utilize its self-assembling behavior with metal oxide nanoparticles in capturing μPs. Surface wettability characteristics revealed the hydrophobic nature of the HPA-modified sponges, with water contact angles exceeding 100°. Polystyrene (PS), a widely used plastic commodity, was chosen as the representative μPs. The adsorption studies on μPs demonstrated a removal efficiency of up to 98 % for PS-NH₂ and 75 % for PS-CO₂H by the optimized sponge. Notably, the NCs exhibited photodegradation of μPs under UV irradiation due to TiO₂ nanoparticles embedded in cellulose matrix. The efficient adsorption capacity combined with remarkable attributes such as easy recovery, recyclability, and biocompatibility of these HPA-functionalized magnetic NCs showcases their potential as a sustainable solution for μPs remediation.

The application of biomass-derived chars in soil amendment has revealed as a promising strategy as a bio-stimulant aimed to futuristic agriculture. Despite the good performance, the rationalization of the mechanisms and the influence of biochars properties upon driving such performance is far from been achieved. In this review we analyze the impact of the application of biochars and related biomass-derived carbons in agriculture soil management, with a focus on the characteristics of the biochars including the pH, ash content, macronutrients contents (mainly N,P,K), surface area, electron conductivity, cation exchange capacity, and the dose of biochars. Interesting results were found for some of these variables. As an attend to normalize the influence of the biochars properties upon different types of crop yields, an increase factor was introduced and up to 72 values were correlated with the dose of biochars. In addition, the effects of the crop type, irrigation, type of soil on crop yields in presence of biochars are also discussed, as well as the effect of biochars on density and microbial contents of soil. Thus, we do believe the quantity of data and the variety variables included in this review are statistically acceptable to stablish a proper assessment about the influence of using biochars as a sustainable amendment for agriculture management. A critical discussion is presented raising the importance of providing a detailed characterization and analysis of the biochars to understand the impact of their application on different crops at various stages of the seasonal crop cycle.

Wastewater treatment plants (WWTPs) are a point source for the release of per- and polyfluorinated alkyl substances (PFAS) into the environment. In our study we investigated wastewater effluent and mixed liquor samples for PFAS in order to obtain information on the current PFAS contamination in municipal WWTPs in Bavaria, Germany. In addition to PFAS target analysis, the total oxidizable precursor (TOP) assay was used as a PFAS sum parameter to obtain information on the precursor concentration in the samples. The sewersheds of the investigated wastewater treatment plants were characterized according to the industrial sectors that discharge into the public sewer system using the Statistical Classification of Economic Activities in the European Community (NACE) code. Known PFAS were detected in all effluent samples, except one, and in concentrations up to 4.700 ng L^-1. The concentrations in effluent samples varied widely between the different sampling dates at the individual WWTPs and also between the different WWTPs. The PFAS concentration in the effluent of 65 % of the WWTPs investigated increased significantly by a factor of 2.9 on average after the TOP assay. In the mixed liquor samples, the PFAS concentration ranged between 56 and 440 μg kg^-1 dw. The concentration varied less than in the effluent samples. After the TOP assay the PFAS concentration in the mixed liquor samples increased on average by a factor of 4. The NACE codes alone cannot be used to determine whether low or high PFAS concentrations are to be expected in a municipal WWTP. However, they can provide an indication of PFAS dischargers and help to prioritize further investigations. Without the TOP assay, the PFAS concentration in the effluent and the mixed liquor samples is clearly underestimated. Our investigations identified hotspots with very high PFAS concentrations in the WWTP effluents. Measures must be taken at the sources to prevent the further release of PFAS into the environment via municipal WWTPs.

Tire particles (TPs) are one of the biggest contributors to microplastic pollution, with reported soil concentrations exceeding 1 % close to busy roads. Little research has been done on the impact of TPs on soil organisms. In this study, two size classes of tire particles, 0-75 μm and 75-180 μm, were compared to determine if size does influence their toxicity to the springtail Sinella curviseta. Adult springtails were exposed for three weeks to TPs spiked in LUFA 2.2 natural soil at concentrations between 0.0016 % and 4 % (w/w). TP addition caused an increase of soil pH at the two highest concentrations, and a dose-related increase of soil Zn concentrations, which were higher for the larger TPs. Available (0.01 M CaCl₂ extractable) Zn concentrations also increased, but were far below toxic levels in all cases. Springtail survival was not affected, but reproduction was decreased by 59 % and 39 % at the highest concentration (4 %) compared to the control for the 0-75 μm and 75-180 μm classes, respectively. EC₅₀s were 3.50 % TPs in soil for the 0-75 μm class and 6.36 % TPs for the 75-180 μm class, and differed significantly between the two size classes (χ²_df = 1 > 3.84, p < 0.05). These results suggest that smaller sized tire particles (0-75 μm) are more toxic to S. curviseta than larger ones (75-180 μm). It may also be concluded that long-term exposure to tire particles may threaten springtail populations at the highest concentrations currently found near roadsides.

The high concentration of heavy metals and persistent organic pollutants in tannery wastewater poses a serious threat to human health and environmental safety. These pollutants are difficult to remove through conventional treatment methods. This study investigates an alternative treatment approach that uses a sequential process that combines a biological stage with electrochemical treatment for improved efficiency. In the initial stage, a microalga isolated from local tannery effluent, identified as Chlorella sorokiniana, was used to remove heavy metals, achieving up to 78.43 % removal of chromium, and the almost complete removal of other toxic metals (99.3 % for As, and 98.9 % for V). Although biological treatment initially led to an increase in chemical oxygen demand (COD), extended incubation times resulted in COD reductions of up to 37 %. Various mixed metal oxide (MMO) anodes were prepared for the electrochemical stage using microwave irradiation for calcination. Tannery wastewater pre-treated with microalgae was further treated electrochemically using Ti/(RuO₂)₀.₉(TiO₂)_0.1 and Ti/(RuO₂)_0.9(Sb₂O₅)_0.1 anodes at different current densities. The Ti/(RuO₂)₀.₉(TiO₂)_0.1 anode, calcined at 400 °C and operated at 60 mA/cm², achieved the highest COD removal of 94.25 %, with further reduction in chromium. Under optimized conditions, the energy consumption was 21.4 kWh/m³, marking the lowest reported for electrochemical treatment of tannery wastewater, highlighting the efficiency of these anodes relative to previous studies. Integrating biological and electrochemical methods, this sequential treatment approach significantly improves the removal of organic compounds, chromium, and other pollutants, demonstrating the synergistic effect of the combined process and presenting a more sustainable and effective solution for tannery wastewater treatment.

Perfluoroalkyl carboxylic acids (PFCAs) are persistent in the environment, and can enter the human body. This study aimed to investigate the in vivo kinetics of branched PFCAs with seven to fourteen carbon atoms (C₇ to C₁₄) using samples collected different individuals: bile (n = 5), urine (n = 10), and cerebrospinal fluid (CSF) (n = 7), with their corresponding serum. This study revealed that the clearance values of PFCAs were greatly affected by whether they were linear or branched. Furthermore, it demonstrated that C₇ and C₈ branched PFCAs had higher total (renal plus fecal) clearance values than their linear counterparts and that they were more easily excreted from the body via urine (higher renal clearances). However, when the chain length was C₉ or longer, the clearance value was almost the same as that of linear PFCAs because fecal clearance through the bile is the main route of clearance from C₉ onwards, and there is no significant difference in fecal clearance between branched and linear ones. The ratio of branched to linear PFCAs in the CSF was similar as that in the serum for all PFCAs (C₇ to C₁₄) measured, and there appeared to be no difference in blood-brain barrier permeability. This information will be useful for evaluating potential health risks related to branched PFCAs.