Dichlorophenol (DCP), a commonly used fungicide and insecticide, is widely found in waters and wastewaters. Herein, the degradation of DCP by Ferrate (Fe(VI)) in different matrices was comprehensively investigated. In pure water, a complete removal of DCP was achieved in 300 s at [Fe(VI)]:[DCP] molar ratio of 2:1. The presence of HA (10 mg L⁻¹) inhibited DCP degradation to a certain extent. A total of twenty degradation products were identified by HPLC/MS analysis. Based on these products, reaction pathways including the cleavage of C–C bridge bond, hydroxylation, and radical coupling were proposed. These reaction mechanisms were further rationalized by theoretical calculations. The analyses of Wiberg bond orders and transition state indicated that C₇–C₈ bond was the most vulnerable site for cleavage, and C₁₂ site was the most likely site for hydroxyl addition. Mulliken atomic spin densities distribution suggested that self-coupling products was easily generated via C–O–C coupling ways. Finally, the feasibility of applying Fe(VI) to degrade DCP (20 μM) in a municipal wastewater effluent and a lake water was evaluated and verified. The findings in this study are of relevance in designing Fe(VI)-based treatment strategy for chlorine-containing persistent pesticides.

The link between zinc exposure and glucose metabolism or the development of type 2 diabetes (T2D) is controversial, and underlying mechanisms are unclear. This study aimed to explore the associations of zinc exposure with glucose-insulin homeostasis traits and the long-term effects of zinc on the development of T2D, and further to estimate the potential roles of inflammation and oxidative damage in such relationships. We investigated 3890 urban adults from the Wuhan-Zhuhai cohort, and followed up every three years. Mixed linear model was applied to estimate dose-response associations between urinary zinc and glycemia traits [fasting plasma insulin (FPI), fasting plasma glucose (FPG), insulin resistance (homeostasis model assessment of insulin resistance, HOMA-IR), and β-cell dysfunction (homeostasis model assessment of β-cell function, HOMA-B)], as well as zinc and biomarkers for systemic inflammation (C-reactive protein) and oxidative damage (8-isoprostane and 8-hydroxy-2′-deoxyguanosine). Logistic regression model and Cox regression model were conducted to evaluate the relationships between urinary zinc and prevalence and incidence of T2D, respectively. We further performed mediation analysis to assess the roles of inflammation and oxidative damage biomarkers in above associations. At baseline, we observed significant dose-response relationships of elevated urinary zinc with increased FPI, FPG, HOMA-IR, and T2D prevalence and decreased HOMA-B, and such associations could be strengthened by increased C-reactive protein, 8-isoprostane, and 8-hydroxy-2′-deoxyguanosine. Elevated C-reactive protein significantly mediated 9.09% and 17.67% of the zinc-related FPG and HOMA-IR increments, respectively. In longitudinal analysis, a significantly positive association between urinary zinc and T2D incidence was observed among subjects with persistent high urinary zinc levels when compared with those with persistent low zinc levels. Our results suggested that high levels of zinc exposure adversely affected on glucose-insulin homeostasis and further contributed to increased risk of T2D cross-sectionally and longitudinally. Moreover, inflammatory response might play an important role in zinc-related glucose metabolic disorder.

The presence of urban greenspace may lead to reduced personal exposure to air pollution via several mechanisms, for example, increased dispersion of airborne particulates; however, there is a lack of real-time evidence across different urban contexts. Study participants were 79 adolescents with asthma who lived in Delhi, India and were recruited to the Delhi Air Pollution and Health Effects (DAPHNE) study. Participants were monitored continuously for exposure to PM₂.₅ (particulate matter with an aerodynamic diameter of less than 2.5 μm) for 48 h. We isolated normal day-to-day walking journeys (n = 199) from the personal monitoring dataset and assessed the relationship between greenspace and personal PM₂.₅ using different spatial scales of the mean Normalised Difference Vegetation Index (NDVI), mean tree cover (TC), and proportion of surrounding green land use (GLU) and parks or forests (PF). The journeys had a mean duration of 12.7 (range 5, 53) min and mean PM₂.₅ personal exposure of 133.9 (standard deviation = 114.8) μg/m³. The within-trip analysis showed weak inverse associations between greenspace markers and PM₂.₅ concentrations only in the spring/summer/monsoon season, with statistically significant associations for TC at the 25 and 50 m buffers in adjusted models. Between-trip analysis also indicated inverse associations for NDVI and TC, but suggested positive associations for GLU and PF in the spring/summer/monsoon season; no overall patterns of association were evident in the autumn/winter season. Associations between greenspace and personal PM₂.₅ during walking trips in Delhi varied across metrics, spatial scales, and season, but were most consistent for TC. These mixed findings may partly relate to journeys being dominated by walking along roads and small effects on PM₂.₅ of small pockets of greenspace. Larger areas of greenspace may, however, give rise to observable spatial effects on PM₂.₅, which vary by season.

Iron-based materials have been widely investigated because of their high surface reactivity, which has shown potential for the remediation of metal(loid)s in groundwater. However, the disadvantages of structural stability and economic feasibility always limit their application in permeable reactive barrier (PRB) technology. In this study, zeolite-supported iron particles (Zeo-Fe) were synthesized by an innovative low-cost physical preparation method that is suitable for mass production. The removal efficiency and mechanism of typical metal(loid)s (Pb²⁺, Cd²⁺, Cr⁶⁺ and As³⁺) were subsequently investigated using various kinetic and equilibrium models and characterization methods. The results of scanning electron microscopy and energy dispersive spectrometry (SEM-EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) confirmed that zero valent iron (Fe⁰) and oxidation product (Fe₃O₄) were successfully loaded and efficiently dispersed on zeolite. The synthesized Zeo-Fe exhibited excellent adsorption and redox capacities for the cations Pb²⁺, Cd²⁺ and anions Cr⁶⁺, As³⁺. The increase in the pH resulting from Fe⁰ corrosion also enhanced the precipitation of Fe-metal(loid)s. The maximum removal capacity for Pb²⁺, Cd²⁺, Cr⁶⁺ and As³⁺ was up to 70.00, 9.12, 2.35 and 0.36 mg/g, respectively. The removal processes were well described by the pseudo-second-order kinetic model for Pb²⁺ and Cd²⁺, Lagergren pseudo first-order kinetics model for As³⁺ and double phase first order kinetics model l for Cr⁶⁺. Cr⁶⁺ was rapidly reduced to Cr³⁺ by the Fe⁰ stabilized on Zeo-Fe, and the oxidation of As³⁺ to As⁵⁺ was attributed to the Fe⁰/Fe²⁺ oxidation process at the interface over time, which was further demonstrated by the mineral phase and element valence analyses of reacted Zeo-Fe. The removal mechanism for metal(loid)s was a combination of physical and chemical processes, including adsorption, co-precipitation and reduction-oxidation. Conclusively, Zeo-Fe has been shown to have potential as an effective and economical material for removing various metal(loid)s used in PRB.

Inhalation exposure to fine particulate matter (PM₂.₅) represents a global concern due to the adverse effects in human health. In the last years, scientific community has been adopted the assessment of the PM₂.₅-bound pollutant fraction that could be released (bioaccessible fraction) in simulated lung fluids (SLFs) to achieve a better understanding of PM risk assessment and toxicological studies. Thus, bioaccessibility of 49 organic pollutants, including 18 polycyclic aromatic hydrocarbons (PAHs), 12 phthalate esters (PAEs), 11 organophosphorus flame retardants (OPFRs), 6 synthetic musk compounds (SMCs) and 2 bisphenols in PM₂.₅ samples was evaluated. The proposed method consists of a physiologically based extraction test (PBET) by using artificial lysosomal fluid (ALF) to obtain bioaccessible fractions, followed by a vortex-assisted liquid-liquid microextraction (VALLME) and a final analysis by programmed temperature vaporization-gas chromatography-tandem mass spectrometry (PTV-GC-MS/MS). The highest inhalation bioaccessibility ratio was found for bisphenol A (BPA) with an average of 83%, followed by OPFRs, PAEs and PAHs (with average bioaccessibilities of 68%, 41% and 34%, respectively). Correlations between PM₂.₅ composition (major ions, trace metals, equivalent black carbon (eBC) and UV-absorbing particulate matter (UVPM)) and bioaccessibility ratios were also assessed. Principal Component Analysis (PCA) suggested that PAHs, PAES and OPFRs bioaccessibility ratios could be positively correlated with PM₂.₅ carbonaceous content. Furthermore, both inverse and positive correlations on PAHs, PAEs and OPFRs bioaccessibilites could be accounted for some major ions and metal (oid)s associated to PM₂.₅, whereas no correlations comprising considered PM₂.₅ major ions and metal (oid)s contents and BPA bioaccessibility was observed. In addition, health risk assessment of target PM₂.₅-associated PAHs via inhalation was assessed in the study area considering both total and bioaccessible concentrations, being averaged human health risks within the safe carcinogenic and non-carcinogenic levels.

Fine particulate matter 2.5 (PM2.5) exposure leads to the progress of pulmonary disease. It has been reported that N6-methyladenosine (m6A) modification was involved in various biological processes and diseases. However, the critical role of m6A modification in pulmonary disease during PM2.5 exposure remains elusive. Here, we revealed that lung inflammation and mucus production caused by PM2.5 were associated with m6A modification. Both in vivo and in vitro assays demonstrated that PM2.5 exposure elevated the total level of m6A modification as well as the methyltransferase like 3 (METTL3) expression. Integration analysis of m6A RNA immunoprecipitation-seq (meRIP-seq) and RNA-seq discovered that METTL3 up-regulated the expression level and the m6A modification of Interleukin 24 (IL24). Importantly, we explored that the stability of IL24 mRNA was enhanced due to the increased m6A modification. Moreover, the data from qRT-PCR showed that PM2.5 also increased YTH N6-Methyladenosine RNA Binding Protein 1 (YTHDF1) expression, and the up-regulated YTHDF1 augmented IL24 mRNA translation efficiency. Down-regulation of Mettl3 reduced Il24 expression and ameliorated the pulmonary inflammation and mucus secretion in mice exposed to PM2.5. Taken together, our finding provided a comprehensive insight for revealing the significant role of m6A regulators in the lung injury via METTL3/YTHDF1-coupled epitranscriptomal regulation of IL24.

This study investigated the role of nocturnal melatonin secretion in the cognitive performance of diurnal animals. An initial experiment measured the cognitive performance in Indian house crows treated for 11 days with 12 h light at 1.426 W/m² (∼150 lux) coupled with 12 h of 0.058 W/m² (∼6-lux) dim light at night (dLAN) or with absolute darkness (0 lux dark night, LD). dLAN treatment significantly decreased midnight melatonin levels and negatively impacted cognitive performance. Subsequently, the role of exogenous melatonin (50 μg; administered intraperitoneally half an hour before the night began) was assessed on the regulation of cognitive performance in two separate experimental cohorts of crows kept under dLAN; LD controls received vehicle. Exogenous melatonin restored its mid-night levels under dLAN at par with those under LD controls, and improved the cognitive performance, as measured in the innovative problem-solving, and spatial and pattern learning-memory efficiency tests in dLAN-treated crows. There were concurrent molecular changes in the cognition-associated brain areas, namely the hippocampus, nidopallium caudolaterale and midbrain. In particular, the expression levels of genes involved in neurogenesis and synaptic plasticity (bdnf, dcx, egr1, creb), and dopamine synthesis and signalling (th, drd1, drd2, darpp32, taar1) were restored to LD control levels in crows treated with illuminated nights and received melatonin. These results demonstrate that the maintenance of nocturnal melatonin levels is crucial for an optimal higher-order brain function in diurnal animals in the face of an environmental threat, such as light pollution.

Emission of antibiotics into riverine environments affects aquatic ecosystem functions and leads to the development of antibiotic resistance. Here, the profiles of forty-four antibiotics and eighteen antibiotic resistance genes (ARGs) were analyzed in two large rivers of the Pearl River System. In addition, the risks of ecotoxicity and resistance selection posed by the antibiotics were estimated. As compared to the reservoirs, the river sections close to the urban and livestock areas contained more antibiotics and ARGs. Seasonal variations of antibiotics (higher in the dry season) and relative ARGs (normalized by 16S rRNA gene, higher in the wet season) were found in the water, but not in the sediment. Sulfonamide resistance genes were the most prevalent ARGs in both river water and sediment. Antibiotic concentration was correlated with ARG abundance in the water, indicating that antibiotics play a critical role in ARG spread. In addition, oxytetracycline was the most abundant antibiotic with concentrations up to 2030 ng/L in the water and 2100 ng/g in the sediment respectively, and posed the highest risks for resistance selection. Oxytetracycline, tetracycline and sulfamethoxazole were expected to be more ecotoxicologically harmful to aquatic organisms, while ofloxacin, enrofloxacin, norfloxacin, chlortetracycline, oxytetracycline and tetracycline posed ecotoxicological risks in the sediment. The Nanliujiang river with intensive livestock activities was contaminated by antibiotics and ARGs and faced high ecotoxicological and resistance selection risks. Collectively, these findings reflect the impacts of anthropogenic activities on the spread of antibiotic resistance in large river basins.

Cropland contamination by toxic trace metal (loid)s (TTMs) has attracted increasing attention due to the serious consequential threat to crop quality and human health. Mitigation of plant TTM stress by silica amendment has been proposed recently. However, the relationship between the siliceous structure of phytoliths and TTMs in plants, and the environmental implications of phytolith-occluded trace metal (loid)s (PhytTMs) remain unclear. This study assessed the accumulation of five metal (loid)s, including lead (Pb), zinc (Zn), cadmium (Cd), copper (Cu) and arsenic (As), in the organic tissues and phytoliths of wheat grown in a mixed-TTM contaminated soil under both lightly and heavily contaminated conditions. The results show that the concentrations of plant TTMs and PhytTMs were significantly (p < 0.05) positively correlated, and higher in heavily contaminated wheats than those in lightly contaminated ones. The bio-enrichment factors between phytoliths and organic tissues were higher for As (1.83), Pb (0.27) and Zn (0.30) than for Cd (0.03) and Cu (0.14), implying that As, Pb and Zn were more readily co-precipitated with silicon (Si) in phytolith structures than Cd and Cu. Network analysis of the relationship between soil and plant elements with PhytTMs showed that severe contamination could impact the homeostasis of elements in plants by altering the translocation of TTMs between soils, plants, and phytoliths. The accumulation of TTMs in phytoliths was affected by the capacity of Si deposition in tissues and chelation of TTMs with silica, which could impact the role of PhytTMs in global biogeochemical TTM cycles.

Cadmium (Cd) contamination in paddy soil often results in elevated Cd concentrations in rice grain, which is a serious concern threatening food safety. Most of the Cd accumulated in rice grain is derived from its remobilization in paddy soil during the grain filling period when paddy water is drained. We have previously shown that the voltaic cell effect controls the oxidative release of cadmium sulfide (CdS) during the drainage period. Metal sulfides with lower electrochemical potentials than CdS can suppress the oxidation of CdS. In the present study, we tested whether amendments of ZnSO₄ or MnSO₄ could enhance the suppressive voltaic effect on Cd release and subsequent accumulation in rice grain. The one-time addition of ZnSO₄ (75 kg/ha Zn) decreased CaCl₂-extractable Cd concentrations in soils by 32–64% in pot experiments and by 16–30% in field trials during the drainage period. Consequently, Cd concentrations in brown rice were reduced by 74–87% and 60–72% in pot experiments and field trials, respectively. Importantly, this effect persisted in the second year without further addition. The amendment of MnSO₄ had similar effects in decreasing soil extractable Cd and Cd concentrations in brown rice. These effects were not attributed to the addition of sulfate. A single application of such doses of ZnSO₄ or MnSO₄ (e.g. 75–150 kg/ha Zn or Mn) only caused a marginal increase in soil Zn or Mn concentrations and had no significant impact on grain yield. Taken together, amendments of ZnSO₄ and/or MnSO₄ (at the rate of 75–150 kg/ha Zn and or Mn) formed a protective voltaic cell partner against the oxidative dissolution of CdS and thus were highly effective in reducing Cd accumulation in rice grain. This work provides a simple but effective method to decrease soil Cd availability during soil drainage and mitigate Cd accumulation in rice to ensure food safety.