Volatile organic compounds (VOCs) from anthropogenic sources, especially cyclic organics with stable structure and strong toxicity (e.g., cyclohexane and benzene), exert hazards to atmospheric environment and human health, and need to be controlled urgently. As an emerging technology for VOC removal, non-thermal plasma (NTP) with low-energy consumption and high removal efficiency is widely studied. However, in contrary to the abundant experiments, theoretical studies are only few, and the degradation mechanisms and pathways of VOCs are still open questions, which hinders the effective VOC removal. Herein, the density function theory (DFT) calculations of NTP degradations for two typical cyclic organics, cyclohexane and benzene, are performed. The degradations of cyclic organics are mainly resulted by the dehydrogenation, decarburation, elimination, and ring-opening reactions and can be markedly promoted with radical ·OH, H·, and O· produced by background gas (H2O and O2). For cyclohexane degradations, the presence of O· decreases the energy barrier from 81.9 to 8.7 kcal/mol in the initial step, leading to an optimal degradation pathway with minimum plasma energy at around 0.5 eV. For benzene degradations, the presence of ·OH decreases the energy barrier from 118.4 to 5.5 kcal/mol in the initial step, triggering an optimal degradation pathway with minimum plasma energy at around 6 eV. The higher plasma energy required in degradation of benzene is due to its more stable structure than alkanes ring. Moreover, the O₂ concentration and plasma energy are suggested to increase for efficient degradation of cyclohexane and benzene, respectively.

Bacterial communities and denitrifiers in polluted paddy soils near e-waste processing centers were explored to investigate the effects of e-waste-derived heavy metals on soil bacteria. The abundance of denitrifying genes (narG, nirK, and nosZ), as well as the total bacterial community in soils, was slightly influenced by heavy metals. However, heavy metals, especially Ni and Cu, had a greater effect on the community structure of denitrifiers than other soil factors. Significant correlations were observed between heavy metals and the abundance of some dominant denitrifiers (P < 0.05). The Cu and Ni content had a significant positive effect on Methylobacterium based on the relative abundance of nitrite reducers to nitrous oxide reducers (P < 0.05). The exploration of the abundance and composition of denitrifiers in e-waste-contaminated paddy soils and their relationship with heavy metal content in soil offer an insight into the influence of heavy metals on denitrification in such soils.

Goethite is a stable and widespread mineral in soil, which affects the transportation and immobilization of heavy metals in soil. Here, the three-dimensional flower-like goethite (TDFLG) was synthesized by refluxing precipitation method. The modified three-dimensional flower-like goethite (MTDFLG) was prepared by NaH₂PO₄ with dipping method. The obtained samples were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) analysis, N₂ adsorption–desorption (BET), and X-ray diffraction (XRD). SEM images showed that the modification of phosphate had no major changes on the morphology of the original sample and the morphology of MTDFLG after adsorbed U(VI) had clearly change. For the goethite and modified goethite, the BET-specific surface area was 229.96 and 203.17 m²/g, respectively. Moreover, the effects of adsorption time, sorbent dose, solution pH, and initial uranium concentration on the uranium adsorption behaviors were investigated using the two materials as adsorbent for the treatment of uranium-containing wastewater. The results showed that MTDFLG had better adsorption capacity than TDFLG on uranium. The increase in uranium removal on MTDFLG was due to the formation of ternary surface complexes (≡FePO₄UO₂). TDFLG and MTDFLG followed the pseudo-second-order kinetic model and the Langmuir adsorption isotherm model, which indicated that uranium adsorption on TDFLG or MTDFLG is mainly based on chemisorption, and the maximum adsorption capacity of two adsorbents is 48.24 and 112.36 mg/g, respectively.

Fipronil (FPN) is a phenylpyrazole insecticide, widely used for agricultural and veterinary activities. Early reports indicated that FIP organ toxicity is primarily mediated by the induction of oxidative stress. Both thymoquinone (TQ) and diallyl sulfide (DAS) are natural antioxidants with established health benefits. This study investigated the potential ameliorative effects of DAS and TQ against FPN-induced toxicity in rats. Thirty-two male Wistar rats (150–180 g) were randomized into four treatment groups, receiving (I) saline, (II) FPN (10 mg/kg bw), (III) FPN with DAS (200 mg/kg bw), and (IV) FPN with TQ (10 mg/kg bw). All treatments were administered once daily for 28 days. The results showed that compared to the control rats, FPN-treated rats had significantly increased (p < 0.05) serum levels of uric acid, urea, creatinine, cholesterol, aspartate transferase, alanine transferase, alkaline phosphatase, lactate dehydrogenase, and γ-glutamyl transferase. Moreover, FPN significantly reduced (p < 0.05) the serum levels of total proteins, albumin, and triglycerides. In addition, compared with the control group, FPN-treated rats had significantly elevated (p < 0.05) malondialdehyde and nitric oxide levels, as well as significantly reduced glutathione concentration and activities of glutathione peroxidase, superoxide dismutase, and catalase enzymes in the hepatic, renal, and brain tissues. Cotreatment with DAS or TQ significantly ameliorated (p < 0.05) the FPN-induced alterations in all the previously mentioned parameters with more frequent restoration of normal control ranges in the TQ group. In conclusion, both DAS and TQ alleviated the oxidative injury of FPN, probably by enhancing tissue antioxidant defenses.

Thallium is an emerging contaminant, which can be retained in scale encrustation within the pipeline and then released to drinking water. It is included in the Priority Pollutant List of the U.S. EPA. In this study, a sample from the water pipeline of Pietrasanta (Italy), affected by the contamination of thallium, is characterized by SEM-EDS, TGA, and FT-IR. Fluorescence spectroscopy is then proposed as the optimal technique for the detection of the contaminant. The functionality of a previously reported fluorescent calix[4]arene-based chemosensor is verified first on a standard solution of thallium nitrate and then on the sample under investigation. The quenching of the fluorescence of the sensor during the complexation of thallium is confirmed, identifying an ON-OFF sensor with high sensitivity, able to detect concentrations as low as 10⁻⁶ M and with high potential of development for the in situ and fast monitoring of the pollutant in the water network.

In this study, we investigate the effect of application rate and timing of liquid swine slurry on leaching of antibiotic-resistant bacteria (ARB) and their antibiotic resistance genes (ARGs) through soil columns. Swine slurry was added to laboratory soil columns at rates of 5000 or 30,000 gal ac⁻¹. For both application rates, rainfall was applied at either 1, 7, or 21 days after slurry application. Column effluent and the top centimeter of soil in the columns were sampled post-rainfall for cultivable bacteria and quantitative PCR was used to quantify tetracycline, methicillin, β-lactam, and erythromycin resistance genetic determinants. We also conducted similar experiments using swine lagoon slurry spiked with antibiotic-resistant E. coli and Salmonella. We found that the concentration of ARB and ARG recovered in the column effluent following application of the swine lagoon slurry generally decreased with increasing lag time between slurry application and simulated rainfall, though most of these decreases were not statistically significant. Moreover, no statistically significant differences in CFU or GU concentration in the column leachate were observed between the low and high slurry application rates. In the experiments using swine slurry spiked with E. coli and Salmonella, concentrations of both microorganisms eluted from fine sand columns were affected by both slurry application rate and lag time; recovery of ARGs, however, was mostly unaffected, but some differences were observed. In columns packed with loamy sand, no recovery was detected in the column effluent for either organism and recovery of ARG was unaffected by manure application rate or rainfall lag time.

The purpose of this study was to analyze the quality of atmospheric deposition, soil, vadose zone water, and plant species in several Urban Allotment Gardens (UAG) in the city of Lisbon, and to correlate its nature and characteristics with their location within the city pressures and with the farming practices, comparing results with similar studies elsewhere. Twenty one metals or metalloids (Ag, Al, As, B, Ba, Be, Cd, Co, Cr, Cu, Fe, Li, Mn, Mo, Ni, Pb, Sb, Se, Ta, V, Zn) and 16 PAHs (acenaphthene, acenaphthylene, anthracene, fluorene, phenanthrene, naphthalene, benzo[a]anthracene, benzo[a]pyrene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[g,h,i]perylene, chrysene, dibenzo[a,h]anthracene, fluoranthene, indeno[1,2,3-c,d]pyrene), pyrene) were analyzed in the atmospheric deposition, and some of these elements/compounds were further analyzed in soils, water, and vegetables. Results show a wide range of concentrations in the city resulting from different soil types and contamination sources. Indexes based on ratios of selected PAHs suggest pyrogenic origins for the PAHs. Metals and metalloids have both anthropogenic and petrogenic origins, the latter mainly for soils with vulcanic origin. Despite the fact that concentrations in soils and waters have exceeded the recommended values in some areas, the lettuce and cabbage rarely presented contamination, with the measured metal values generally under legislated limits, where this exist.

Due to low cost and large abundance, coal continues to be one of the major energy sources for electricity generation in the USA. The dry desulfurization of flue gases during coal combustion produces a by-product that may be potentially useful as a soil amendment. However, the influence of dry flue gas desulfurization (DFGD) by-products on trace element losses with runoff from treated fields has not been well investigated. The objective of this study was to evaluate the effects of land application of a high-Ca, DFGD by-product on trace elements lost in runoff from natural rainfall events. The by-product was applied once on May 18, 2015 at 9 Mg DFGD ha⁻¹ to small plots of a highly weathered Ultisol under managed-grassland land use in northwest Arkansas. Runoff was collected following each runoff-producing precipitation event for 1 year. Seasonal (i.e., summer (May to August), fall (August to November), winter (November to February), and spring (February to May)) runoff, annual runoff, runoff pH, and electrical conductivity did not differ significantly between DFGD treatments. Seasonal flow-weighted mean Ni concentrations and seasonal V loads were significantly greater in runoff when amended versus the unamended control when compared during at least one 3-month season by 44.5 and 86.9% for Ni and V, respectively. Based on the results of this study, it appears that land application of a high-Ca DFGD by-product at rates ≤ 9 Mg ha⁻¹ has minimal effects on trace elements in runoff.

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