Water, Air, & Soil Pollution最新文献

This study investigates the potential of neem seed waste as an adsorbent for reducing total dissolved solids (TDS), hardness, calcium, and magnesium concentration in groundwater. Groundwater samples were collected from various locations within Quaid-e-Awam University of Engineering, Science and Technology (QUEST) and Nawabshah city. The objective of this research is to optimize the use of neem seed powder for removal of TDS, hardness, calcium, and magnesium concentration and physicochemical parameters from groundwater samples. Different dosages (0.5, 1.0 1.5, 2.0, 2.5, 5.0, and 10.0 g) and retention speed (0, 50, 100, 125, 150, 175, 200) were tested to optimize the treatment process. At a neem seed powder dosage of 2.0 g, a notable reduction in TDS was observed, with values of 48% for S1, 45% for S2, 52% for S3, and 58% for S4, respectively. Additionally, under a retention speed of 150 rpm, a significant decrease in TDS concentrations was recorded, with reductions of 72%, 65%, 79%, and 62% for S1, S2, S3, and S4, respectively. These results underscore the adsorbent's efficiency. Characterization techniques such as FESEM and FTIR were employed to understand the adsorption mechanism. The neem seed powder exhibited a considerable surface area of 55.30 m²/g according to BET analysis. Kinetic adsorption analysis showed a good fit with the pseudo-second-order (PSO) model with R² values 0.9978, 0.9946, 0.9967, and 0.9954 for TDS, Hardness, Calcium, and Magnesium. A higher R-squared value indicates that the PSO model aligns more closely with the data compared to the pseudo-first-order (PFO) model. The adsorbent molecules undergo a chemical reaction between surface molecules and adsorbate. This indicates chemisorption of adsorbs molecule. The study concludes that neem seed powder is a viable option for TDS removal due to its cost-effectiveness and availability compared to other materials like sodium zeolite and kaolin. Future research could explore the applicability of neem seed powder for removing other contaminants in groundwater or provides valuable insights into utilizing agricultural waste for groundwater treatment, offering a sustainable solution to water quality challenges.

Pesticide pollution of surface water is a serious global problem. This research was focused on the monitoring of pesticides in surface waters and their subsequent removal using adsorption on activated carbon (AC). Based on the monitoring, four pesticides—acetamiprid, diethyltoluamide, thiacloprid and thiamethoxam—occurred in higher concentrations in all sampling points. Invasive plants occurring near monitored water bodies, Reynoutria japonica (RJ) and Impatiens glandulifera (IG) were used for the preparation of activated carbon with an activating agent (H₃PO₄ and NaOH) using microwave pyrolysis. The prepared AC was subsequently used for adsorption of the above-mentioned pesticides. The prepared AC was characterized by Brunauer–Emmett–Teller analysis, elemental analysis, Fourier transform infrared spectroscopy and scanning electron microscopy. Individual AC types showed different effects for different pesticides. The maximum adsorption capacity calculated from the Langmuir model was 18.30 mg g⁻¹ for thiacloprid on H₃PO₄-activated AC from I. glandulifera.

Climate-smart farming practices are increasingly essential to address the challenges of food security and water scarcity amidst changing environmental conditions. Earthworms play a pivotal role in enhancing soil health and resilience, contributing to sustainable agricultural production. Their activities improve soil structure, facilitate water infiltration, and enhance nutrient cycling, promoting plant growth and development. By sequestering carbon in the soil, earthworms contribute to mitigating climate change. Additionally, they help to reduce soil erosion and improve water retention, leading to more efficient water use and reduced reliance on external inputs. Furthermore, earthworms can help to mitigate the negative impacts of air pollution by reducing the release of harmful gases. Integrating earthworms into agricultural systems can be a promising strategy for adapting to climate change. However, further research is needed to optimize their use and fully understand their potential benefits. By harnessing the ecological services provided by earthworms, we can promote sustainable agriculture and ensure food security in a changing climate.

The temporal and spatial prediction and early warning of soil heavy metal pollution are crucial for preventing and controlling soil environmental contamination and optimizing the utilization of regional soil resources. This study investigates the spatiotemporal prediction and early warning of soil heavy metal pollution in a lead–zinc mining area in Chifeng City, Inner Mongolia. Soil samples were collected at various depths and times across the mining area and its surroundings. A combination of BP neural network and grey prediction models was used to forecast the distribution of heavy metals, providing a basis for soil pollution control and remediation. The BP neural network model showed that As, Cu, Zn, and Cd concentrations exceeded the risk screening values set by the Soil Environmental Quality Risk Control Standard for Agricultural Land (GB15618-2018), with significant enrichment of As and Cd. Pb showed slight contamination. Spatial analysis indicated that contamination was most severe near the mine and decreased with distance and depth. Grey prediction results suggested that As and Cu levels in the mine restoration area would decline over the next three years, with Cu potentially falling below risk levels by 2024. However, As and Cu levels are expected to increase in surrounding agricultural and unremediated areas. The study concludes that the combined use of BP neural network and grey prediction models is effective for predicting and managing soil heavy metal contamination, supporting targeted remediation efforts in mining regions.

Bioremediation is a promising environmental friendly strategy for the treatment of oil drilling waste, which is particularly challenging in arid areas concerned by high petroleum production activities. Microbial consortia adapted to such environmental conditions are required for the implementation of bioaugmentation treatments. Here four metal(loid)s-resistant hydrocarbon-degrading microbial consortia growing at 40 °C were obtained from oil drilling waste maintained in different phyto-management conditions. The microbial consortia exhibited different microbial compositions with the capacity to degrade 15 to 35% of total petroleum hydrocarbon in 15 days. The hydrocarbon degradation resulted in different hydrocarbon fraction profiles underpinned by the presence of 14 specific OTUs revealed by linear discriminant analysis effect size (LEfSe). Each consortium was characterized by the presence of genera groups, defined according to their correlation with the hydrocarbon fractions, explaining their different degradation capacity and the resulting hydrocarbon fraction profiles. Thus, these consortia can be used in combination or successively to implement bioremediation strategies for the treatment of multi-contaminated oil drilling waste in arid environments.

Microplastics (MPs) are plastic debris having a size ≤ 5 mm. The detrimental impact of MPs on the environment and, consequently, their dangerous effects on human health (emerging risk) have attracted much attention in recent years. Contamination by microplastics is difficult to measure, due to the non-standardization of collection, detection, and analysis techniques. This work consists of a bibliographic review of the analysis of the pros and cons of the various existing legislations at the international level, identifying the possible legislative gaps, intending to improve the efficiency of implementation of new policies on plastics and microplastics, offering the possible recommendations to address potential human and environmental health hazards caused by MPs pollution. Future studies on the mentioned subject should focus on a uniformity of methodology for the determination of microplastics and at the same time, offer help to governments, to write a legislative policy on plastics that is valid at the international level, to help the green earth and completely avoid the risk to human health.

Enhancing the efficacy of semiconductor photocatalysts through the doping of rare-earth ions is a viable approach for regulating their behaviour. The current study employs a solvothermal method followed by calcination to produce Bi₅O₇I photocatalysts doped with rare earth elements (Sm, Nd, and Dy). Ciprofloxacin was used as the target pollutant for all produced catalysts. Among all, Sm-doped Bi₅O₇I exhibited optimal degradation efficiency against ciprofloxacin. Sm doping was identified to be responsible for increased visible light absorption and enhanced separation of light-induced carriers, leading to increased performance in photocatalysis. The Sm doped Bi₅O₇I also showed good adaptation to higher initial ciprofloxacin concentrations and the requisite photodegradation stability after four cycles. Furthermore, the up-conversion luminescence feature of Sm increased the catalyst's visible light usage range. The scavenging experiment identified ·O₂⁻, h⁺, and ¹O₂ as active chemicals in the photocatalytic degradation of ciprofloxacin. Based on this fact, a possible degradation mechanism was postulated. This work may serve as a guide for creating doped bismuth-rich halides for waste water remediation.

Gorgan Bay is located along the southeast Caspian Sea and surrounded with significant agricultural and urban areas. Plastic pollution is a significant issue that affects aquatic ecosystems globally. The accumulation and degradation of plastics into microplastics in aquatic ecosystems highlight the importance of studying them to assess pollution risks. So, an investigation was conducted for the assessment of MicroPlastics pollution (MPs) in water and sediment of this ecosystem. The study involved collecting water and sediment samples from 40 stations within the Bay. Microplastics (MPs) extracted from these samples were identified using microscopic detection methods, specifically visual observation under polarized light to SEM–EDX, and µ-Raman. A total of 16,360 MP particles per kilogram of sediment, and 211 particles per liter of water were detected. The research demonstrated that the river inlets situated within agriculturally intensive regions of the watershed exhibited the highest levels of microplastics (MPs) in both water and sediment samples. Fiber MPs were the most frequent (> 50%) shape in sediment and water. The size of mostly MPs (> 90%) was smaller than 1,000 µm. The dominant polymer within MPs in Gorgan Bay sediment identified as polypropylene (PP), polyethylene (PE), and polystyrene (PS), while polypropylene (PP) and polyethylene (PE) were the frequent polymer in water, respectively. The most amount of MPs was found in the areas close to the rivers and agricultural fields (including stations S4, S12, S13, S14, S22).

Plant configuration and earthworms play an important role in water purification and greenhouse gas emissions in constructed wetlands (CWs). However, the impact of earthworm density on greenhouse gas emissions across different plant configurations has not been explored. In this study, four wetland plant species, Canna indica, Lythrum salicaria, Oenanthe javanica, and Typha orientalis, were selected for monocultures. Under each monoculture, three earthworm densities (control, low, and high densities) were conducted to explore the effects of earthworm density on greenhouse gas emissions in CWs with different plant configurations. The results showed that: (1) in systems without earthworms, the CO₂ emission from O. javanica monoculture was 69.9% lower than that from C. indica monoculture; the CH₄ emission decreased with the increasing earthworm density across all plant configurations, with high earthworm density resulting in negative CH₄ emission. (2) In systems with low and high-density earthworms, C. indica exhibited the highest biomass among four monocultures. However, earthworm density did not significantly affect plant biomass under the same plant configuration. (3) In systems without earthworms, the substrate organic carbon (SOC) of O. javanica monoculture was 18.94% and 4.93% lower than that in T. orientalis and C. indica monocultures, respectively; For L. salicaria monoculture, the SOC was 35.69% and 40.59% lower in systems without earthworms compared to those with low and high-density earthworms, respectively. (4) In systems without earthworms, the global warming potential (GWP) value, including GWP_{CH4+CO2+N2O+SOC}, GWP_{non-CO2+AGB+SOC}, and GWP_{CH4+CO2+N2O+AGB+SOC} were lowest in L. salicaria monoculture among four monocultures. Moreover, in L. salicaria monoculture, the GWP_non-CO2+SOC of systems without earthworms was 36% and 40.7% lower than in systems with low and high-density earthworms by, respectively. These results indicate that adding high-density earthworms can reduce CH₄ emissions in constructed wetlands with different plant configurations. L. salicaria monoculture without adding earthworms demonstrated a low global warming potential.

Straw return is a sustainable agricultural strategy aimed at raising soil organic carbon (SOC), but tends to stimulate nitrous oxide (N₂O) emissions, potentially counteracting gains in SOC sequestration. Nevertheless, knowledge gaps remain on how long-term different forms of straw incorporation (direct straw return or pyrolyzed to biochar) affect N₂O production and reduction, and interactions with associated key nitrogen (N)-cycling microbial communities. Here, the emission rates and proportions of N₂O and N₂ emissions were quantified using a 13-year field trial with sequential incorporation of straw or straw-derived biochar, and interactions with key functional genes were assessed by metagenomic sequencing. Results revealed that incorporation of straw and biochar increased N₂O emission rates by 2.55 and 0.54 folds, while that of N₂ by 6.41 and 9.77 folds, respectively, compared with conventional fertilization. Correspondingly, the N₂O/(N₂O + N₂) ratios were reduced by 10.75% and 39.74% with straw and biochar treatments. Higher N₂O emissions with straw incorporation were primarily driven by concurrent increase in labile C and N sources with nitrate and nitrite reducers (narG, narH, nirK, nirS, norB) outweighing the N₂O reducer (nosZ). In contrast, biochar incorporation decreased nitrate levels, increased electron conductivity and the N₂O reducer (nosZ), which accelerated N₂ emissions and reduced the N₂O/(N₂O + N₂) ratio. Moreover, reduced N₂O/(N₂O + N₂) ratios were closely associated with altered denitrifier communities, with genera belonging to Acidobacteriota being the key contributors to biochar incorporation, and Pseudomonadota being the dominant contributors to straw. Overall, biochar incorporation was more efficient in reducing global warming potential and increasing SOC sequestration, as evidenced by lower N₂O/(N₂O + N₂) ratios and higher SOC levels. This work provides valuable insights designing net-zero C strategies towards sustainable agricultural C sequestration and greenhouse gas mitigation to address the challenges posed by global climate change.