ACS Environmental Au最新文献

Background: Natural water sources are increasingly contaminated with a wide range of pollutants including heavy metals and pharmaceuticals. Arsenic, particularly in its more toxic trivalent form, i.e. As(III), remains a significant environmental and public health concern due to its widespread presence and carcinogenic effects. In addition to that, pharmaceutical products like metronidazole (MNZ) and nalidixic acid (NAL), persistent in the environment due to their limited biodegradability, also pose significant threats to both ecosystems and human health. Recent research has highlighted the formation of antibiotic-metal complexes (AMCs) where antibiotics interact with heavy metals in aquatic environments, leading to altered physicochemical properties and increased toxicity. Aim: The main objective of the present work is a speciation study on As(III)–antibiotic complexes and particularly interaction between As(III) and MNZ or NAL in aqueous solution. Methods: Several temperatures and ionic strengths were probed by potentiometry to determine the formation constants and other thermodynamic parameters of As(III)–MNZ and As(III)–NAL complexes. UV spectrophotometric titrations were also employed to confirm formation constants of both systems. An estimation of the sequestering ability of both ligands toward As(III) under relevant natural water conditions has also been performed. Further, density functional theory calculations have been executed with the purpose of investigating the molecular structure of these complexes and their relative stability. Results: It turns out that MNZ binds to As(III) in either a neutral (AsMNZ) or protonated (As(MNZ)H) form via As–N and As–O interactions, with the hydroxyl oxygen being the preferred binding site in AsMNZ and both the nitro and hydroxyl groups being equally effective in As(MNZ)H, while NAL forms a stable chelated complex through bidentate coordination. Conclusion: Findings reported in this study contribute to a deeper understanding of the complexes formed by As(III) with pharmaceuticals and pave the way toward the development of improved technologies for the water treatment and remediation of AMCs.

Hydrothermal carbonization (HTC) offers significant potential for converting residual waste streams into advanced carbon materials with diverse applications. However, a key challenge in scaling up HTC is managing the large volumes of organic-rich filtrate produced during the process. Through a resting process, the filtrate can be repurposed to produce self-generated carbon (SGC). The spontaneously formed SGC exhibited a spherical morphology and low ash content, even when derived from complex, ash-rich precursors such as anaerobic digestate. SGC production from HTC filtrate may open up a new valorization route for industrial and municipal side-streams. In this study, we investigate how temperature, time, and agitation influence SGC yield, morphology, and particle size distribution. The cumulative yield was measured at intervals (days 2, 5, 7, 9, 26). The average cumulative yield after 26 days increased by 102 % at 50 °C compared to 20 °C, but decreased by 42 % at 4 °C. Agitated samples had the highest yield, increasing by over 260 % at 20 °C. The products showed variations in morphology and size distribution, with agitated samples producing more uniform and smaller particles. SEM imaging indicated a distinct product at 4 °C, with no visible spherical material being generated. Our results imply that changes in temperature and agitation are highly influential in the formation of SGC and may be used in optimizing product yield, sphere size and uniformity. The consistent formation rate over the 26-day period suggests that extending the experimental duration could further increase material yield. This is supported by mass balance calculations.

Amid the global rise in wildfire events, the health impacts of wildfire-related air pollution are increasingly scrutinized. While numerous reviews have examined the link between air pollution and infectious diseases, reviews specifically focusing on wildfire-related air pollution and infectious diseases remain scarce. To address this gap, we conducted a comprehensive search in MEDLINE, EMBASE, Scopus and Web of Science databases up to December 31, 2023, using PRISMA (Preferred Reporting Items for Systematic Reviews & Meta-Analyses) guidelines. Search terms included synonyms of wildfire and infectious diseases. Peer-reviewed epidemiological studies that reported any association or trend between wildfire air pollution and infectious diseases were selected against eligibility criteria. Risk of bias and quality of included studies were assessed using modified risk of bias and quality assessment tools. Our review included 30 studies, predominantly from developed countries including the United States (USA), Australia, and Canada. Most focused on respiratory infectious diseases (n = 29), including 9 specifically on the coronavirus disease 2019 (COVID-19). The majority examined short-term wildfire air pollution (n = 27) (exposure of one month or less). Twenty-three studies reported effect estimates for the meta-analysis. We found that a 10 μg/m³ increase in short-term wildfire PM_2.5 (particulate matter with a diameter of 2.5 micrometer of less) exposure was associated with a 15% increase in COVID-19 infections (relative risk [RR] = 1.15; 95% confidence interval [CI]: 1.09-1.21; heterogeneity (I ²): 83%), a 3% increase in respiratory diseases (RR = 1.03; 95% CI: 1.01-1.05; I ²: 0%) and a 3% increase in acute upper respiratory infection combined with acute bronchitis (RR = 1.03; 95% CI: 1.02-1.05; I ²: 62%). Medium-term exposure (more than a month but less than a year) to wildfire smoke was associated with 20% rising hospitalization for systemic fungal infections like coccidioidomycosis (95% CI: 5-38%). The current research exclusively examines respiratory infections in developed countries. Future high-quality primary studies should prioritize understanding the impact of wildfire-related air pollution on various infectious diseases.

External organic matter (EOM), particularly from municipal waste, can contaminate soil when used to amend it. This may limit the benefits of using such an EOM to improve soil health and mitigate climate change. However, certain treatments may reduce the initial contaminant load of EOM. This study aimed to evaluate whether EOM processing can reduce its cytotoxicity and the concentration levels of 34 persistent and emerging organic contaminants. Sewage sludge and a mixture of manure and straw, processed by pyrolysis and anaerobic digestion to generate biochar and digestate, respectively, were selected for this study. An in vitro fish cell cytotoxicity test was performed to assess the toxicity of organic and aqueous extracts from the EOMs. It was found that organic contaminants are generally highly matrix-bound, resulting in low availability, reduced potential for leaching to groundwater, and effects on soil organisms after EOM application. The pyrolysis of sludge resulted in the almost complete removal of bisphenol A, tris(2-chloroisopropyl)phosphate, and octylphenol (removal ≥95%), while the concentration of the other contaminants monitored was reduced, with the exception of polycyclic aromatic hydrocarbons (PAHs) of lower molecular weight. In contrast, anaerobic digestion of manure did not result in a reduction of the contaminant load monitored except for bisphenol A. Cytotoxicity was also observed in aqueous extracts of manure but was reduced by anaerobic digestion. This suggests that anaerobic digestion could reduce potential hazards to groundwater or surface water from manure amendments. Organic EOM extracts were cytotoxic, indicating the presence of toxic products strongly adsorbed to these EOMs and retained in the soil after amendment.

Constructed wetlands (CWs) have gained scholarly attention in the last two decades as promising technologies for the attenuation of trace organic contaminants (TrOCs) from municipal wastewater effluent and combined sewer overflow discharge. Using lab-scale vertical flow constructed wetlands, we investigated amending these systems with Fe-EDTA to improve CW degradation of five representative trace organic contaminants. The study combined a 7-month monitoring campaign, 3 different hydraulic regimes, and soil extraction data to elucidate the effects of the amendment on the fate of the TrOCs within the systems. Our results indicate that Fe-EDTA contributed to the degradation of carbamazepine and sulfamethoxazole under the studied flow regimes. Iron-amended soil columns (n = 5/9 columns fed for 7 months with synthetic domestic wastewater) removed 12 ± 19% of influent carbamazepine (the most recalcitrant TrOC included in the study), 18% higher than the control columns. Operating the columns with periods of retention and discharge further improved carbamazepine and sulfamethoxazole removal efficiency (removal increased to 49 ± 7.6% and 81 ± 9.2% of influent concentrations, respectively). The more readily degradable compounds atenolol and trimethoprim were removed with >97% efficiency in both control and amended columns, regardless of flow. This column study positively correlates Fe-EDTA with improved removal efficiencies of environmentally recalcitrant TrOCs without affecting readily degradable TrOCs.