Water, Air, & Soil Pollution最新文献

Indoor air pollution from solid fuel combustion is a major health risk in developing nations. In Tanzania, over 80% of households rely on biomass and fossil fuels for cooking. While transitions to cleaner fuels are occurring, kerosene remains widely used in urban areas like Dar es Salaam. This study employed cross-sectional techniques among 59 households randomly selected from Mbagala, Dar es Salaam, to characterize indoor air quality and self-reported respiratory symptoms from kerosene and liquefied petroleum gas (LPG) cooking. Indoor concentrations of carbon monoxide (CO), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), and particulate matter (PM10) were measured using portable analyzers during morning and evening cooking sessions. Questionnaires gathered data on household demographics, cooking practices, housing characteristics, and self-reported health symptoms. Compared to LPG stoves (n = 28), kerosene stoves (n = 31) emitted significantly higher indoor levels of CO (mean 56 ± 8 vs. 18 ± 1.2 ppm), NO₂ (3.6 ± 0.6 vs. 1.4 ± 0.22 ppm), and SO₂ (2.8 ± 0.4 vs. < 0.1 ppm) exceeding WHO guidelines. Poor ventilation was common. Time spent cooking and household size correlated positively with pollutant concentrations (p < 0.05). Common health issues reported included cough (65%), asthma (30%), and chest pain (25%). Kerosene use was associated with higher indoor air pollutant concentrations and a higher prevalence of self-reported respiratory symptoms than LPG. Interventions are needed to accelerate transitions to cleaner fuels and improve household ventilation. Strategic investments could help reduce exposure and disease burden from indoor air pollution in the study area and other places with similar challenges.

Co-occurrence of heavy metals and plastic-derived pollutants represents a novel challenge for agroecosystem sustainability, yet the mechanistic interplay between biochar (BC) amendments, microplastics (MPs) and cadmium (Cd) remains largely unresolved. A controlled greenhouse factorial experiment arranged in a completely randomized factorial design with six replicates per treatment was conducted to elucidate the BC-MPs-Cd interactions in a loamy slightly neutral soil cultivated with wheat (Triticum aestivum L.). Treatments included two Cd levels (0, 10 mg kg⁻¹), three MPs doses (0, 1, 2% w/w) and two BC rates (0, 1% w/w). BC application markedly increased soil pH (up to 8.11) and organic matter, while reducing DTPA-extractable Cd by up to 36% under Cd10MP2, indicative of pH-driven sorption and precipitation processes. MPs, in contrast, enhanced Cd mobility in a dose-dependent manner in BC-free soils. Elevated Cd bioavailability under Cd10 + MPs treatments resulted in substantial increases in shoot and grain Cd concentrations (20.2 and 4.00 mg kg⁻¹, respectively) and concomitant reductions in biomass and grain yield (15–26% decreases), whereas BC partially mitigated these effects by lowering tissue Cd accumulation (~ 12% reduction). Nitrogen dynamics remained largely unaffected, while Zn availability exhibited secondary yet significant shifts. PCA revealed distinct clustering along Cd mobility versus plant performance axes, reflecting the contrasting regulatory roles of BC and MPs. Overall, BC functioned as a robust chemical buffer against Cd stress even under MPs presence, whereas MPs exacerbated Cd bioavailability and phytotoxicity. These findings provide critical insights into multi-contaminant interactions and underscore the necessity of integrated remediation strategies in contaminated agricultural soils.

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In the nitrogen cycle of agricultural ecosystems, ammonia volatilization is an important way of nitrogen loss and makes a significant contribution to nitrogen deposition. In South China, high nitrogen deposition threatens both ecological balance and food security. This study assessed the effects of organic fertilizer substitution, optimized irrigation, and reduced tillage on crop yield, crop nitrogen use efficiency (NUEc), and NH₃ volatilization in rice, maize, and vegetables. We also examined the relationship between NH₃ volatilization and nitrogen deposition. Organic fertilizer substitution improved agricultural performance, increasing crop yields by 3.0–5.3%, enhancing NUEc by 2.2–3.6%, and reducing NH₃ emissions by 7.9–21.8%. Optimized irrigation resulted in a 1.8–4.2% increase in yield, a 1.4–5.1% improvement in NUEc, and an 8.4–13.7% reduction in NH₃ volatilization. Conversely, reduced tillage had no significant impact on crop productivity, yet it was associated with reduced NUEc and increased NH₃ emissions. Wet deposition accounted for 80.0–83.3% of the total nitrogen deposition flux in the experimental area, with ammonium nitrogen as the dominant form. NH₃ volatilization was positively correlated with nitrogen deposition (R² = 0.278, p < 0.05) (Fig. 7). Organic fertilizer substitution and shallow wet irrigation enhanced ammonium-to-nitrate conversion by increasing soil organic matter and prolonging water residence time, thus improving NUEc and reducing NH₃ volatilization and nitrogen deposition.It could contribute to ensuring food production safety and improving regional environmental quality in South China.

Water is essential to human health, economic development, and productivity. Many contaminants have significantly affected the quality of water over time; thus, predicting water quality using modern tools is vital for mitigating water pollution. This research focused on an intensive examination of two distinct lakes. 80 surface water samples were taken randomly from each lake for 8 months continuously and tested in laboratory for physicochemical characteristics to determine the drinkability of the two lakes. However, 8 Spin Karez samples Lake and 18 Hanna Lake samples were deemed unsafe to drink. The samples were classified as drinkable or non-drinkable based on their drinkability values. The first six months of drinkability data were used to train the algorithms, and then the remaining two months of drinkability data were forecasted. Confusion matrix was used to examine the prediction performance of seven distinct supervised machine learning (ML) algorithms – Linear Regression (LR), Decision Tree Classifier (DTC), Random Forest (RF), XGBoosting (XGB), K-Nearest Neighbor (KNN), Support Vector Machines (SVM), and Adaptive Boosting (Adaboost). The models accurately predicted the water quality with DTC outperforming for both lakes. This study contributes to the evolution of prediction tools by integrating ML with environmental monitoring for sustainable water resource management.

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Excessive nitrogen discharge into the environment causes water eutrophication and threatens human health, making efficient N removal from wastewater crucial. This study investigates the nitrogen removal performance of sequencing batch biofilm reactor (SBBR) by varying cycle times (12 h, 8 h and 6 h). Using synthetic wastewater simulating domestic sewage, SBBR reactors were operated with K3 fillers, controlled dissolved oxygen (DO) (6–7 mg/L), and temperature (22 °C). Results showed that at an 8 h cycle, SBBR achieved high removal rates of carbon (C) and nitrogen (N), with efficiencies of 97.22% for COD, 93.51% for NH₄⁺-N, and 90.46% for TN. Microbial community analysis via metagenomic sequencing indicated that the dominant bacteria, such as Pseudomonadota, Bacteroidota, Acidobacteriota and Chloroflexota, and the key genus, such as Pseudomonas, Nitrospira and Thauera, have enhanced nitrogen removal performance. At the same time, the nitrogen metabolism pathways were analyzed, identifying functional genes including amoAB, hao, nxrAB, narGHI, and nosZ. These findings lay a foundation for optimizing SBBR for efficient wastewater treatment.

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A series of composites AC-ZnO(1-x)/Bi₄Ti₃O₁₂(x) (30, 50, and 70 wt. %) with enhanced optical properties are fabricated using a cost-effective molten salt synthesis involving ethanol as solvent to create a varying bonding between pure Bi₄Ti₃O₁₂ (BTO) and activated carbon (AC) prepared from potato plant waste (PPW). X-ray diffraction analysis confirms the high crystallinity of BTO, and the appearance of ZnO and ZnC reflects ethanol's effectiveness in the preparation of composites. Scanning electron microscopy with energy-dispersive X-ray spectroscopy reveals the formation of BTO plates homogeneously dispersed onto AC layers. Fourier-transform infrared spectroscopy analysis manifests characteristic vibration bands thus confirming the chemical composition of AC-ZnO/BTO composites. The presence of active modes in Bi₄Ti₃O₁₂ nanocrystals as investigated by Raman spectroscopy confirms the orthorhombic structure and the respective bands of carbon materials for the composite AC-ZnO (0.7) / BTO (0.3). Brunauer–Emmett–Teller analysis reflects a large surface area with an increase in AC-ZnO amount up to 324.80 m²/g. The photocatalytic activity for the degradation of cationic organic dye (Rhodamine B) is found to be mainly influenced by the ratio of AC-ZnO:BTO and the exposure duration, with the PPW-ZnO content having a significant impact. The AC-ZnO (0.7) / BTO (0.3) demonstrates the best photocatalytic performance, reaching 99.9% after 20 min. A plausible photocatalytic process for RhB over AC-ZnO (0.7) / BTO (0.3) composite is proposed based on the active species trapping experiments. This research designed a novel facile method for fabricating semiconductor-based activated carbon composites with improved photocatalytic performance for the degradation of organic pollutants in contaminated water.

This study investigates the treatment of stabilized landfill leachate by a hybrid Fenton process assisted with microwave (MW), ultrasound (US), and UV-A irradiation (MW-US-UV-A-Fenton). The combined effects of Fe²⁺ concentration, H₂O₂ concentration, and MW power were optimized using a Box–Behnken design, and the optimal conditions were subsequently validated experimentally. Under these optimized and validated conditions ([Fe²⁺] = 1369.39 mg/L, [H₂O₂] = 5584.14 mg/L, MW power = 856.60 W), the treatment achieved 81% removal of chemical oxygen demand (COD), complete color removal (100%), and 87% reduction of Abs254, confirming the effective degradation of refractory organic matter in stabilized leachate. Removal efficiencies for other parameters, including turbidity, salinity, and nitrate, ranged from 52 to 95%, while chloride concentration decreased markedly from 22.765 g/L to 1.72 g/L. UV–visible spectra (250–300 nm) further revealed a strong decrease in absorbance, consistent with the reduction in COD and organics content. In addition, a laboratory-scale cost analysis showed that the process operated with a total operational cost of 5.34 USD/m³ (5.26 USD/m³ for chemicals and 0.078 USD/m³ for energy) and a specific energy consumption of 0.978 kWh/m³, corresponding to 0.489 kg CO₂/m³ emitted. According to these findings, this advanced oxidation process (AOP) efficiently treats stabilized landfill leachate and represents a promising option for the remediation of other complex effluents containing refractory compounds.

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Increasing metal demand requires to move toward circular economy. This study explores domestic wastewater as a potential metal resource, assessing the effective recovery of 16 metals, 2 metalloids and phosphorus by 4 adsorbents (activated alumina, activated carbon, clinoptilolite, ferric hydroxide) and two cation-exchange resins (weak and strong). It is the first to evaluate the removal of such a wide range of elements—19 in total—comparing six different sorbents taking into account the complexity of a real wastewater, and thus providing tangible insights for the development of a recovery process. A design of experiments using batch-tests was set-up to study the effects of the material dosage, contact time and pH, and has determined the best operating conditions. We have shown that three materials have captured > 60% of the elements: P, Si, As, V, Zn, Mo, Cr and Sb for the ferric hydroxide, B, Co, Cr and Zn for the activated carbon, and Ca, Mg, Sr and Zn for the weak cation-exchange resin. A dosage of 20 g.L⁻¹ of material was shown optimal for the capture by activated carbon and ferric hydroxide, while the weak cation-exchange resin performed best at 4 g.L⁻¹. A contact time of 1 h was identified as optimal for most elements and tested materials. The recovery would be substantial for Ca, Na, K, Mg, P, Si, Sr, but is still a challenge for others. Poor elements retention were shown for activated alumina and zeolite-clinoptilolite, and rapid saturation for the strong cation-exchange resin.

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The development of efficient and stable adsorbents for the removal of Rhodamine B (RhB) is of great significance in mitigating its environmental hazards. In this study, a nitrogen-doped carbon composite (Mn-MoO_x@NC) was successfully synthesized via high-temperature annealing of [N(C₄H₉)₄]₃[MnMo₆O₁₈{(OCH₂)₃CNH₂}₂] (MnMo₆) and dicyandiamide (DCA). The resulting material exhibited excellent adsorption performance, with a maximum adsorption capacity of 390.56 mg/g and a removal efficiency of 96% after five adsorption-desorption cycles. The adsorption process fitted well with the Freundlich isotherm model (R²=0.995) and the pseudo-second-order kinetic model (R²=0.99), indicating that chemisorption played a dominant role. Thermodynamic analysis revealed that the adsorption of RhB was spontaneous and exothermic. Notably, this study prepared oxide composite nanomaterials from polyoxometalates (POMs) derivatives through a one-step calcination method and applied them for the first time to the adsorption of RhB, providing a novel strategy for the removal of organic pollutants.

This study evaluates the biosorption potential of Hypotrachyna cirrhata for effective removal of Cu(II) ions from synthetic wastewater, emphasising its functional chemistry and adsorption behaviour. Atomic Absorption Spectroscopy (AAS) was used to quantify Cu(II) before and after biosorption. Fourier Transform Infrared (FTIR) spectroscopy analysis revealed shifts in hydroxyl, carboxyl, and carbonyl groups, demonstrating their involvement in surface complexation and metal-binding interactions. Scanning Electron Microscopy-Energy Dispersive X-ray (SEM–EDX) showed clear surface modification and supported FTIR findings by confirming the presence of copper on the lichen surface. The biomass exhibited strong affinity towards Cu(II) ions, with adsorption equilibrium data fitting the Langmuir model and revealing monolayer adsorption with a maximum adsorption capacity of 6.68 mg g⁻¹. Kinetic evaluation showed that the biosorption follows the pseudo-second-order model, suggesting chemisorption as the dominant rate-controlling step. Thermodynamic parameters (ΔG°, ΔH°, and ΔS°,) confirmed the spontaneous and endothermic nature of Cu(II) uptake. These findings highlight the novelty of H. cirrhata as an eco-friendly biosorbent and provide clear insight into its adsorption mechanism, supporting its potential use in wastewater treatment.