Previous studies have demonstrated the side effects of tooth whiteners on the gastric mucosa. However, the impact of dental bleaching products on the liver, kidney, and heart remains obscure. The present study investigated the toxic potential of 35% carbamide peroxide (CPO) containing tooth whitening product (TWP) on the liver, kidney, heart, and stomach of mice, pointing to the role of oxidative stress and inflammation. Mice received 250 or 500 mg/kg body weight CPO-TWP orally for 3 weeks and samples were collected for analyses. Both doses of CPO-TWP induced a significant increase in circulating liver, kidney, and heart function markers. CPO-TWP-administered mice showed several histological alterations and a significant increase in liver, kidney, heart, and stomach lipid peroxidation levels along with diminished glutathione, superoxide dismutase, and catalase. In addition, administration of CPO-TWP provoked anemia, leukocytosis, and a significant increase in circulating levels of pro-inflammatory cytokines. In conclusion, exposure to 35% CPO-TWP induced functional, histological, and hematological alterations, oxidative stress, and inflammation in mice. Therefore, the frequent use of tooth bleaching agents should be monitored very carefully to avoid the application of excess amounts as well as the intake.

High specific surface area activated carbon prepared from endocarp of Jerivá (Syagrus romanzoffiana) (ACJ) was used for ciprofloxacin (CIP) antibiotic removal from aqueous effluents. The activated carbon (AC) was characterized via scanning electron microscope, Fourier transform infrared spectroscopy, N₂ adsorption/desorption, and pH value at the zero-charge point. Avrami kinetic model was the one that best fit the experimental results in comparison to the pseudo-first-order and pseudo-second-order kinetic models. The equilibrium data obeyed the Liu isotherm equation, showing a maximum adsorption capacity of 335.8 mg g⁻¹ at 40 °C. The calculated thermodynamic parameters indicate that the adsorption of CIP was spontaneous and endothermic at all studied temperatures. Also, the free enthalpy changes (∆H° = 3.34 kJ mol⁻¹) suggested physical adsorption between CIP and ACJ. Simulated effluents were utilized to check the potential of the ACJ for wastewater purification. The highly efficient features enable the activated carbon prepared from endocarp of Jerivá, an attractive carbon adsorbent, to remove ciprofloxacin from wastewaters.

Multi-level ditch area is a major component of the hydrographic net of plain area, China. Given the high concentration of nitrogen (N) in the surface water and vigorous biogeochemical interactions, ditch is likely to be the hot spots of N₂O emission. However, N₂O emission flux and emission factor (EF₅ᵣ) of multi-level ditches have not been determined. To address this knowledge gap, a 1-year field work in three ditches with different levels in Chengdu Plain was conducted. It is found that the annual flux of N₂O emission and EF₅ᵣ was higher in the lateral (0.0020 and 83.94 μg m⁻² h⁻¹) and field ditches (0.0019 and 110.75 μg m⁻² h⁻¹) than in the branch ditch (0.0016 and 46.38 μg m⁻² h⁻¹, P < 0.05). It is found that parameters of groundwater level, discharge, precipitation, and NH₄⁺ were the primary factors, and these parameters can model the N₂O flux well. Furthermore, the content of NH₄⁺ in the surface water of ditches presented better correlation with the emission of N₂O than the content of NO₃⁻. Therefore, controlling NH₄⁺ emission and lessening fertilizer usage in summer may be key solutions for indirect reduction of N₂O in Chengdu Plain.

Usage of atrazine, a widely used herbicide, is now banned in many countries. Although forbidden to use, significant concentration of this herbicide is still present in the environment. The study focused not only on the toxicity of atrazine itself but also on products of homogeneous photocatalytic degradation. Such degradation was very fast in given conditions (sufficient amount of Fe(III) in the reaction system)—more than 95% of the initial amount of atrazine was eliminated after 30 min of irradiation. The toxicity of atrazine and its photodegradation products were examined on the aquatic plant Lemna minor and microcrustacean Daphnia magna in both acute and chronic tests. While the growth inhibition assay of atrazine for Lemna minor revealed EC₅₀ value of 128.4 μg dm⁻³, the herbicide did not affect Daphnia in the acute toxicity assay. A degradation product, desethyl-atrazine, has been demonstrated to have a pronounced negative effect on the plant growth. Both atrazine and desethyl-atrazine affect negatively the number of juveniles and number of clutches of Daphnia magna in the chronic toxicity assay. Photocatalytic degradation lowers the negative effect of atrazine in Daphnia magna while photodegradation products still negatively affect Lemna growth.

High-surface-area activated carbons were prepared from an agroindustrial residue, Bertholletia excelsa capsules known as capsules of Para cashew (CCP), that were utilized for removing amoxicillin from aqueous effluents. The activated carbons were prepared with the proportion of CCP:ZnCl₂ 1:1, and this mixture was pyrolyzed at 600 (CCP-600) and 700 °C (CCP700). The CCP.600 and CCP.700 were characterized by CHN/O elemental analysis, the hydrophobic/hydrophilic ratio, FTIR, TGA, Boehm titration, total pore volume, and surface area. These analyses show that the adsorbents have different polar groups, which confers a hydrophilic surface. The adsorbents presented surface area and total pore volume of 1457 m² g⁻¹ and 0.275 cm³ g⁻¹ (CCP.600) and 1419 m² g⁻¹ and 0.285 cm³ g⁻¹ (CCP.700). The chemical and physical properties of the adsorbents were very close, indicating that the pyrolysis temperature of 600 and 700 °C does not bring relevant differences in the physical and chemical properties of these adsorbents. The adsorption data of kinetics and equilibrium were successfully adjusted to Avrami fractional-order and Liu isotherm model. The use of the adsorbents for treatment of simulated hospital effluents, containing different organic and inorganic compounds, showed excellent removals (up to 98.04% for CCP.600 and 98.60% CCP.700). Graphical abstract

The adsorption properties and mechanisms of methylene blue (MB) onto novel biochars produced by the fallen leaves of Magnolia grandiflora Linn (MGL), at different pyrolysis temperatures (450 °C, 500 °C, 550 °C) were explored. Results of the adsorption experiments revealed that the fallen leaf-biochar of MGL (MGLB) pyrolyzed at 450 °C (MGLB450) had the highest adsorption capacity of MB (114.15 mg g⁻¹) and MGLB pyrolyzed at 500 °C (MGLB500) was lowest (88.13 mg g⁻¹). The characterization results showed that the BET surface area (41.784 m² g⁻¹) and total pore volume (0.043 cm³ g⁻¹) of MGLB450 were low, but the contents of oxygen-containing functional groups were highest. Oxygen-containing functional group might have a greater impact on the adsorption of MB than its physical characteristics. The adsorption capacity increased with reaction temperature, indicating that the MG adsorption onto biochars was endothermic. The higher initial concentrations of MB and pH were beneficial to adsorption. The adsorption kinetics showed that the adsorption followed pseudo-second-order kinetics model. The obtained equilibrium data were fitted better by Langmuir model rather than Freundlich model.

Constructed wetlands (CWs) have been applied to remediate heavy metal pollution effectively in practice. However, the heavy metal release from CWs has not been paid enough attention. In this study, a 5-month experiment was carried out with three parallel lab-scale vertical flow constructed wetlands (VFCWs) with zeolites as fillers. The artificial rainwater was pumped into VFCWs to study the release characteristic and mechanisms of heavy metals (Cu, Zn, Cr, and Pb). The results showed that significant amounts of Zn and Cu were released from the VFCWs at the end of the experiment while Pb and Cr rarely escaped. The upper layer (0–30 cm) of the VFCWs was the most effective area for heavy metal removal due to the presence of sediments, but it was also the most active area for heavy metal release. To explain this result, the sediments were analyzed before and after being leached by the tap water. The results indicated that Zn and Cu existed mainly in the exchangeable state, and they had strong leachability and bioavailability, causing its releases. Also, competitive adsorption of different metals meant that the metal ions with strong adsorption to zeolite caused the metal ions with weak adsorption to be desorbed from zeolites, and thus, a large amount of Zn escaped from VFCWs. The escape of heavy metals from CWs illustrated that it should be paid more attention in the management.

Application of fungicides on grapevines is the main source of soil contamination by copper and zinc. Studies on this issue in relatively young grapevines are common; however, studies that elucidate the metal transfer in a soil-plant-food production system in a centenarian vineyard are scarce. The present work was aimed at tracing the copper and zinc accumulation in three different compartments—soil, plant, and vine products—in young and centenarian vineyards. Soil samples were collected in the middle plant row and rhizosphere positions of the vineyards; samples of root and leaf tissue and of grape juice and wine from these vineyards were also collected. In the centenarian vineyard, the soil available copper, regardless of vineyard position, reached 1100 mg kg⁻¹. Copper in root and leaf tissues reached 12,300 mg kg⁻¹ and 6800 mg kg⁻¹, respectively. In grape juice and wine, copper was 9.08 mg L⁻¹ and 0.78 mg L⁻¹, respectively. The roots retained most part of the metals reducing their transfer through the system. However, Cu levels in the grape juice from the centenarian vineyard exceeded by 908% the limit established by Brazilian and international norms. Zinc concentrations in soil and vine products were within the permitted level. Finally, the magnitude of metal transfer and accumulation is due to decades of cupric fungicide application and varies according to the compartment evaluated. The findings will provide information to rethink the vineyard agricultural practices in order to avoid environmental contamination by metals and compromising the whole food chain.

Contamination with fluoroaromatics (FAs), particularly polyfluorinated aniline, is becoming a serious environmental problem worldwide. To shorten the start-up time, and increase the stability of treatment systems, this work focused on the effects of three seeding sources on treatment performances of 2,3,4-trifluoroaniline (2,3,4-TFA) during start-up and shock, as well as the acclimated strategy. After 246–323 days of acclimation in a stepwise feeding according to the inhibition degree, three sequencing batch reactors (SBRs) successfully achieved efficient removal, i.e., 300.00 mg/L of 2,3,4-TFA, with over 95.00% of degradation efficiency and 60.00–80.00% of defluorination rates. The sludge obtained from the fluorizated hydrocarbon wastewater treatment plant(FHS) without prior exposure to fluoroaniline was determined to be optimal, based on the observed shortest start-up time of 246 days, the highest defluorination rate of 70.00–80.00%, the fastest recovery time of 7 days after shock, and the highest microbial diversity with nine dominant bacterial groups. Furthermore, compared with the sludge obtained from pharmaceutical wastewater containing part of municipal wastewater treatment plant(PMS), the seeding source used in treating the comprehensive wastewater in industrial park (CIS) exhibited earlier defluorination reaction, higher defluorination rate and microbial diversity, but lower shock resistance. High-throughput sequencing demonstrated that microbial diversity was dependent on the origin of the inoculum after acclimation. We identified two predominant phyla in PMS, namely, Deinococcus-Thermus (24.43%) and Bacteroidetes (18.44%), whereas these were Acidobacteria and Chloroflexi in FHS and CIS. During the shock of 400 mg/L 2,3,4-TFA, the predominant bacteria norank_f_Blastocatellaceae and norank_f_Methylobacteriaceae disappeared, and the defluorination reaction hardly occurred, indicating that the bacterial genera could contribute to the defluorination reaction.

This paper presents an experimental study of suspended particle transport through sand layer using a new self-developed sand layer transportation-deposition testing system, and the study aims to identify the effects of temperature on the transport of suspended particles through porous medium. Four typical temperatures (5 °C, 15 °C, 25 °C, and 35 °C) were considered in our study, and the experiments were conducted under four size compositions and three flow velocities (1.5 cm/s, 0.2 cm/s, and 0.04 cm/s). The tests were conducted using quartz sand as the porous medium and quartz powder as particles to monitor the change in turbidity under the different conditions. The breakthrough curves were analyzed, and the results demonstrated that changes in temperature can affect the breakthrough curves, especially at the peak. The influence is particularly significant under lower flow velocities and for smaller particles. In regard to the influence factors on the transport process, water viscosity and adsorption effect can be regarded as promoting factors, while kinetic energy of particles can be classified as constraining factors.