Water, Air, & Soil Pollution最新文献

Understanding the behavior of pathogenic bacterial groups from domestic wastewater in surface water is critical to improving sanitation risk assessment and supporting effective policy implementation. Despite their importance, their behavior in freshwater environments is not fully understood. This study examined the behavior of pathogenic bacterial groups frequently found in domestic wastewater–Aeromonas, Arcobacter, and Mycobacterium—in freshwater microcosms containing domestic wastewater with different initial ammonium-nitrogen (NH₄⁺-N) concentrations (2, 5, and 15 mg N L⁻¹). Digital polymerase chain reaction (dPCR) assays with propidium monoazide (PMA) pretreatment were used to evaluate the behavior of viable targeted bacteria. Aeromonas and Arcobacter decayed quickly after the experiment began, with typical first-order decay constants of 0.718 to 0.820 day⁻¹ and 1.14 to 1.19 day⁻¹, respectively. These rates were comparable or higher than those of Escherichia coli, an indicator of fecal contamination (0.586–0.680 day⁻¹). Conversely, the abundance of Mycobacterium increased over the course of the 7-day experiment. The decay or growth of the target bacterial groups in the microcosms under aerobic conditions was not affected by varying NH₄⁺-N concentrations. Sequencing of the near-full-length 16S ribosomal ribonucleic acid (16S rRNA) gene amplicons with PMA pretreatment revealed that the primary Aeromonas and Arcobacter populations in the initial microcosms were pathogenic species relatives. Conversely, the major Mycobacterium populations thriving in the microcosms were presumably uncultured species with low 16S rRNA gene sequence similarity (< 98.65%) to the cultured species. This study provides insights to improve sanitation risk assessment and promote suitable policy implementation.

Black carbon aerosols and PM2.5 have been identified as one of the major factors responsible for the ambient air quality index in Jamshedpur. The real-time measurement of BC concentration is determined with the help of an Aethalometer (AE-33), which was analyzed from November 2022 to April 2023. In the present study, we have compared the aerosol parameters during haze (Nov-Jan) and normal days (Oct, Feb-May) periods. We estimated the average mass concentration of BC, PM2.5 and AQI during haze days (HD) and normal days (ND), respectively. BC concentrations showed significant temporal variations with around 6.25 ± 3.05 and 2.52 ± 2.75 μg m − 3 during HD and ND, respectively. While PM2.5 and AQI concentrations in HD were found to be 264.64 ± 58.8 and 267.84 ± 56.72 μg m − 3, which were double of 130.19 ± 60.1 and 141.98 ± 52.44 μg m − 3, respectively, during ND. The highest monthly concentration of BC, PM2.5 and AQI was noticed in December at 8.35, 291.9 and 298 μg m − 3, respectively. Large-scale energy production in industries can consume coal and petroleum as primary fuels, which may be a major reason for the high concentrations. Due to low mixing height during winter, these emissions are not spread properly. Hence, higher concentration was found in December. The values for BC/PM2.5 were observed as 2.37% with a range from 0.54 to 4.4% and 2.48% (0.5 to 21.78%) during HD and ND, respectively. The study determined the source apportionment of BC with biomass dominance found in HD. The % BB was obtained around 53.1% throughout haze session, which was approximately 1.57 times higher than normal day (33.77%). In winter, burning wood and other solid fuels to warm the atmosphere may increase the contribution of BB to BC emissions. Furthermore, the backward trajectories calculated that air masses were concentrated within the IGP regions at lower altitudes during the HD while there was a diverse circulation of air parcels throughout the ND. Air masses were majorly coming to the receptor site from west India in ND. GIOVANNI NASA satellite model proved that surface mass concentrations of BC and PM2.5 were observed higher over IGP areas as well as other parts of India during HD with respect to ND.

Graphical Abstract

Natural coagulants are emerging as effective alternatives to inorganic coagulants in wastewater treatment due to their high coagulation-flocculation activity, abundance, cost-effectiveness, and biodegradability. Despite their potential, research has largely been limited to laboratory-scale experiments, with few studies exploring pilot-scale applications. This study investigates pine cones, a novel and underutilized waste material, as a bio-coagulant for wastewater treatment plants (WTPs). The active coagulating agent was extracted from pine cones treated with a 0.5 M sodium chloride (NaCl) solution. Characterization was performed using Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM), and chemical analysis, revealing significant quantities of coagulating agents responsible for effective coagulation. A jar test was initially conducted to determine the optimal coagulant dosage, initial pH, and settling time for the coagulation-flocculation process. The process was modeled and optimized for turbidity, chemical oxygen demand (COD), and phosphate removal using response surface methodology (RSM) with a Box Behnken design (BBD). The optimal conditions identified were a 10 ml/L coagulant dosage at pH 10 and a settling time of 115 min. Experimental data and model predictions showed good agreement, with R² values of 99.12%, 93.52%, and 98.11% for turbidity, COD, and phosphate removal, respectively. Jar tests under these conditions achieved removal efficiencies of 98.81%, 72.02%, and 86.44% for turbidity, COD, and phosphate. The optimized conditions were then applied on a pilot scale, showing removal efficiencies of 97.77%, 71.35%, and 88.6% for turbidity, COD, and phosphate. Our findings highlight pine cones as an effective, cost-efficient, and eco-friendly alternative for WTPs.

Total petroleum hydrocarbon (TPH) in wastewater has attracted widespread attention for its environmental and biological health hazards. In the research, WY-4 strains with diesel degradation ability isolated from contaminated soil and response surface methodology was used to optimize the degradation conditions of WY-4. Fe-modified biochar (FPB) was used as an immobilized carrier, the environmental factors affecting the degradation of immobilized bacteria (FPBM) were explored and the degradation effect of FPBM was evaluated on real TPH-contaminated wastewater. Furthermore, the potential degradation mechanisms and possible degradation pathways of TPH were also explored. The results demonstrated that WY-4 was identified as Ochrobactrum sp., and its optimal growth conditions were pH 6.8, temperature 28.8°C and NaCl concentration 9.47 g/L. The removal efficiency by FPBM on 10,000 mg/L diesel wastewater was 72.5% and on real TPH-contaminated wastewater was 76.75% in 7 d, which was significantly higher than the degradation effect of free bacteria. The degradation pathway of two representative pollutants, naphthalene and indole, in the real TPH-contaminated wastewater was referred to be the catechol metabolic pathway. The results highlighted the potential of FPB-immobilized bacteria for the remediation of TPH-contaminated wastewater in harsh environments and provided an effective strategy for green remediation treatment of TPH contamination.

Reactive oxygen species (ROS) frequently detected in water systems require thorough investigation due to their widespread occurrence and potential health risks. This study sought to clarify the impact of ROS on zebrafish—a widely-used model organism in aquatic toxicology—and antibiotic-resistant bacteria. We explored how ROS exposure affects zebrafish brain activity, uncovering a notable increase in abnormal cognitive function, which points to possible neurological disruption. Moreover, the elevated ROS production, especially from heavy metals in natural water systems, induces 'oxidative stress,' which not only challenges antibiotic-resistant bacteria but also promotes biofilm formation and facilitates plasmid transfer. Unlike previous studies that primarily focused on heavy metal toxicity, our research highlights the role of free radical generation from metal-environment interactions. The development of innovative toxicity assessment models is imperative for accurately evaluating the ecological risks of these contaminants. This study emphasizes the critical need to understand the dual impact of ROS on zebrafish and antibiotic-resistant bacteria, guiding the development of strategies to mitigate their ecological and public health consequences in aquatic ecosystems.

This study focuses on the innovative production of Bio-Graphene Foams (BGFs) from sustainable resources, aimed at addressing the critical challenge of efficiently removing harmful chlorophenols—specifically 2,4-dichlorophenol (DCP) and 2,4,6-trichlorophenol (TCP)—from wastewater. In this investigation, we present an innovative and streamlined methodology to address the constraints encountered in the fabrication of biomass-derived Graphene Foams (bGFs). Our primary focus is on customizing their extensive surface area and structural attributes to align with the specific requirements of environmental applications, particularly for the adsorption of chlorophenols. We developed a distinctive BGF with a highly porous, spongy structure and an impressive specific surface area of up to 805 m²/g through a two-step synthetic process. Our method not only enhances the environmental applicability of BGFs but also demonstrates their superior adsorptive capabilities. The adsorption performance of the BGFs was rigorously evaluated, with a focus on capacity, kinetics, and the influence of pH. Comprehensive studies on the effects of pH, contact time, adsorbent dosage, and phenolic content were conducted. The adsorption isotherms for DCP and TCP adhered to the Langmuir model, revealing an outstanding adsorption capacity of 245 mg of pollutant per gram of BGF at an optimal pH of 3–4. Remarkably, BGFs reduced the concentration of phenolic derivatives in water to levels below the World Health Organization’s acceptable limit for human use (0.050 mg/dm³). This research highlights the significant potential of Bio-Graphene Foams as highly effective adsorbents for environmental remediation. The challenges associated with synthesizing such high-performance materials and optimizing their application for wastewater treatment were successfully addressed, marking a substantial advancement in the field.

Owing to their widespread use, sulfonamide antibiotics (SAs), an important class of emerging pollutants, have caused significant ecological disruption. Both acid deposition and salinization of soil may have an impact on migration and degradation of antibiotics. Sulfamethoxazole (SMX), has a migration and transformation process in the environment that is closely dependent on environmental pH. Nevertheless, scarcely any studies have been conducted on the effect of soil pH changes on the environmental behavior of sulfamethoxazole. To investigate the impact of different pH levels on the migratory mechanisms and degradation pathways of SMX within soil systems, indoor soil column leaching experiments were conducted. Ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF–MS) were used to analyse the dynamic changes in the content of SMX as well as to identify its degradation products. The results showed that acidic conditions constrained the vertical migration of antibiotics in the soil. These transformations ensued through a sequence of reaction processes, encompassing ring opening, hydroxylation, S-C bond breaking, and the oxidation of aniline groups. The study of the migration and transformation of sulfamethoxazole under different pH conditions can lay a solid theoretical foundation for the assessment of the pollution risk of sulfamethazine degradation products under acid rain and salt and alkali conditions, so as to better prevent and protect underground water resources.

Denitrification coupled to methane oxidation (DOM) has been shown to be an appropriate process for wastewater treatment applications, since it can reduce greenhouse gas emissions and nitrogen discharges, making wastewater treatment plants more environmentally sustainable. Study of DOM has focused on laboratory-scale application using membrane biological reactors (MBR) or sequency batch reactors (SBR), which have been shown to be able to retain DOM biomass and therefore appropriate for use with this process. However, it is necessary to expand knowledge of the behavior of this process using other configurations, with a view to scaling up. Therefore, in this study, an upflow fixed bed bioreactor (UFBR) was implemented using plastic carriers such as bioballs and Biochips® to carry out the DOM process under anoxic conditions. The reactor reached stable nitrogen removal conditions after approximately 400 days of continuous operation, forming a biomass composed of denitrifying methane-oxidizing microorganisms where the genus Anaerolinea and Methylocystis predominated. Once the biomass was formed and the DOM process was stabilized, maximum nitrite and nitrate removal rates of 17.6 mgN-NO₂⁻/L-d and 8.9 mgN-NO₃⁻/L-d, respectively, and a removal efficiency of methane up to 77% were obtained. This demonstrates the feasibility of the application of the DOM process under anoxic conditions using fixed bed bioreactors, which is promising for further nitrogen removal from wastewater using a varied reactor configuration easily to scaled-up.

Herein, chicken bone (CB) and rice waste (RW) food were converted to activated carbon (CBRWAC) via microwave assisted H₃PO₄ activation. The applicability of CBRWAC as an efficient adsorbent was evaluated for its removal  efficacy of a cationic dye, namely methyl violet (MV), from an aqueous environment. The physicochemical properties of CBRWAC were characterized by several analytical methods such as BET, XRD, pH_pzc, FTIR, and SEM–EDX. The Box-Behnken design (BBD) was adopted to optimize the effect of three adsorption processing variables namely CBRWAC dose (0.02–0.1 g/100 mL), solution pH (4–10), and contact time (10–200 min) for the removal of MV dye. The results of the equilibrium and kinetic investigation indicates that the adsorption of MV dye by CBRWAC was well described by the Langmuir and Freundlich isotherm models, as well as the pseudo-second-order model for adsorption kinetics. The CBRWAC has a maximum adsorption capacity (q_max) of 126.3 mg/g. The proposed adsorption mechanism of MV by CBRWAC was assigned to the electrostatic interactions, π -π stacking, pore filling, and H-bonding. The current investigation highlights the possibility of food waste conversion into activated carbon with potentially wider utility for the removal of a wider range of toxic cationic dyes from contaminated water.

This research explores the complex interactions between agricultural activities, microbial ecology, particulate matter concentrations, and bacterial aerosols, with a focus on their implications for human health and agricultural sustainability. Through extensive field studies, we examined the distribution of Gram-positive and Gram-negative bacteria across different agricultural activities, revealing distinct patterns linked to these practices. Our results show that sowing and fertilization promote the proliferation of Gram-positive bacteria, while weeding favors Gram-negative species. Specifically, during sowing, Gram-positive bacteria made up 75% of the bacterial population, whereas during weeding, Gram-negative bacteria constituted 75%. Irrigation and harvesting displayed balanced microbial compositions, with each bacterial group representing 50% of the population. Additionally, we measured particulate matter concentrations during various agricultural tasks, finding elevated levels of PM1 (48 µg/m3 during weeding), PM2.5 (65 µg/m3 during weeding), PM10 (86 µg/m3 during weeding), CO2 (1027 ppm during irrigation), and formaldehyde (0.013 ppm during harvesting). These results highlight the need for targeted mitigation strategies to protect air quality and human health in agricultural settings. Our analysis of bacterial aerosols revealed significant variations in bioaerosol concentrations, ranging from 30 CFU/ml during weeding to 80 CFU/ml during fertilization. This underscores the importance of implementing effective risk management measures to address potential health impacts. Furthermore, we identified both pathogenic and beneficial bacterial species within agricultural ecosystems, stressing the importance of preventive measures against contamination while leveraging beneficial bacteria to improve crop productivity and soil fertility. Overall, this study enhances our understanding of the interplay between agricultural practices, microbial dynamics, and human health, informing more sustainable agricultural management practices.