The N, S, and Fe-tridoped carbon catalysts (NSFe-Cs), Fe/ACNS1 and Fe/ACNS2, were synthesized by wet impregnation with different concentration of ammonium ferrous sulfate solution. The prepared catalysts have a similar textural structure. The N species, S species, Feᴵᴵ and Feᴵᴵᴵ were simultaneously introduced onto the surface of catalysts. Comparison with the only Fe doped catalyst, NSFe-Cs showed greater stability and higher phenol removal in catalytic wet peroxide oxidation at different reaction condition. The main intermediates including p-hydroxybenzoic acid, formic acid, and maleic acid were determined in the treated wastewater. The high catalytic activity for NSFe-C was related to the ability of H₂O₂ decomposition. NSFe-Cs have more amount of Feᴵᴵ partially due to the formation of FeS₂, which promoted the decomposition of H₂O₂ on Fe/ACNS1 and Fe/ACNS2 surface. The generation of ·OH and ·HO₂/·O₂⁻ radicals in the bulk solution was crucial to phenol degradation, and the decomposition of H₂O₂ complied with the pseudo-first-order kinetics. The highly linear relationship between decomposition kinetic constant for H₂O₂ and the amount of surface groups suggested, including Feᴵᴵ species, pyridinic N/Fe-bonded N, pyrrolic N as well as graphitic N were responsible to the high activity of NSFe-Cs.

As inland freshwaters act as a major transport pathway for marine microplastic pollution, microplastic pollution in freshwater systems has recently received growing attention. However, the role of environmental and spatial factors in shaping the distribution and characteristics of microplastic pollution in reservoir ecosystems is not well understood. Here, we studied microplastic pollution in the surface water of the Yulin River, a typical tributary of the upper reaches of the Three Gorges Reservoir (TGR). The abundance of microplastics were 1.30 × 10⁻², 1.95 × 10⁻¹ and 3.60 × 10⁻¹ items/L in the mainstream, tributaries and bays of the Yulin River, respectively. Polyethylene, polypropylene, and polystyrene were identified as the predominant types. The most common shapes were line/fiber and foam. Small-sized particles dominated the collected microplastics. Aged surface was identified by scanning electron microscopy and X-ray photoelectron spectroscopy. The microplastics in the Yulin River were largely of secondary origin. Microplastic pollution varied in space. The abundance of microplastic was higher upstream reaches than downstream, which was correlated with anthropogenic activity. The backwater of the TGR increased the abundance of microplastic in the estuary of the Yulin River. The abundance of microplastic was negatively correlated with the channel width. This study is helpful for understanding the characterics and distribution of microplastics in reservoir ecosystems within underdeveloped area, and can thereby inform well-directed strategies to mitigate microplastic pollution.

The effect of microplastics (MP) exposure on the chironomid species Chironomus riparius Meigen, 1804 was investigated using the OECD sediment and water toxicity test. Chironomid larvae were exposed to an environmentally relevant low microplastics concentration (LC), a high microplastics concentration (HC) and a control (C). The LC was 0.007 g m⁻² on the water surface + 2 g m⁻³ in the water column + 8 g m⁻² in the sediment, and the HC was 10 X higher than this for each exposure. The size of the majority of the manufactured microplastic pellets varied between 20 and 100 μm. The MP mixture consisted of: polyethylene-terephtalate (PET), polystyrene (PS), polyvinyl-chloride (PVC) and polyamide (PA) in a ratio of 45%: 15%: 20%: 20%, respectively, for the sediment exposure; 100% polyethylene for the water column exposure; and 50% polyethylene: 50% polypropylene for the water surface exposure. Different endpoints were monitored, including morphological changes in the mandibles and mentums of 4th instar larvae, morphological changes in the wings, mortality, emergence ratio, and developmental time. A geometric morphometric analysis showed a tendency toward widening of the wings, elongation of the mentums and changing the shape of the mandibles in specimens exposed to both concentrations of microplastics. The development time of C. riparius was significantly prolonged by the MP treatment: 13.8 ± 0.5; 14.4 ± 0.6; and 15.3 ± 0.4 days (mean ± SD) in the C, LC, and HC, respectively. This study indicates that even environmentally relevant concentrations of MP mixture have a negative influence on C. riparius, especially at the larval stage.

Current practices employed by most wastewater treatment plants (WWTP) are unable to completely remove endocrine disrupting compounds (EDCs) from reclaimed waters, and consistently discharge these substances to receiving systems. Effluent-dominated and dependent surface waters, especially during low instream flows, can increase exposure and risks to aquatic organisms due to adverse biological effects associated with EDCs. Given the ecological implications that may arise from exposure to such compounds, the present a multi-approach study examined spatio-temporal estrogenic potential of wastewater effluent to fish in East Canyon Creek (ECC), Utah, USA, a unique urban river with instream flows seasonally influenced by snowmelt. Juvenile rainbow trout (Oncorhynchus mykiss) were caged at different upstream and downstream sites from an effluent discharge during the summer and fall seasons. In the summer, where approximately 50% of the streamflow was dominated by effluent, fish from the upstream and a downstream site, located 13 miles away from the effluent discharge, presented significantly elevated concentrations of plasma vitellogenin (VTG). Similarly, significantly high 17β-estradiol to 11-ketotestosterone ratios were measured in the summer across all sites and time points, compared to the fall. In the laboratory, juvenile fish and primary hepatocytes were exposed to concentrated effluent and surface water samples. Quantification of VTG, although in significantly lower levels, resembled response patterns observed in fish from the field study. Furthermore, analytical quantification of common EDCs in wastewater revealed the presence of estriol and estrone, though these did not appear to be related to the observed biological responses, as these were more significant in sites were no EDCs were detected. These combined observations suggest potential estrogenicity for fish in ECC under continuous exposures and highlight the advantages of following weight-of-evidence (WoE) approaches for environmental monitoring, as targeted analytically-based assessments may or may not support the identification of causative contaminants for adverse biological effects.

In the context of Coronavirus Disease (2019) (COVID-19) cases globally, there is a lack of consensus across cultures on whether wearing face masks is an effective physical intervention against disease transmission. This study 1) illustrates transmission routes of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2); 2) addresses controversies surrounding the mask from perspectives of attitude, effectiveness, and necessity of wearing the mask with evidence that the use of mask would effectively interrupt the transmission of infectious diseases in both hospital settings and community settings; and 3) provides suggestion that the public should wear the mask during COVID-19 pandemic according to local context. To achieve this goal, government should establish a risk adjusted strategy of mask use to scientifically publicize the use of masks, guarantee sufficient supply of masks, and cooperate for reducing health resources inequities.

Recycled materials were used in three types of green sorption media for nutrient removal and possible recovery in high nutrient-laden agricultural discharge and stormwater runoff. The three types of green sorption media included in this comparative study were two new aluminum-based green environmental media (AGEM) and one existing iron-filings based green environmental media (IFGEM). The corresponding adsorption isotherm, thermodynamics, and kinetics models were simulated based on isotherm studies to determine their removal efficiency and potential for recovery of nitrate, phosphate, and ammonia when used as a soil amendment in crop fields or in a filter for water treatment. AGEM-2 exhibited the shortest contact time required to achieve nutrient removal above 80% with an average of 7 h, followed by AGEM-1 and IFGEM with 10.6 and 28 h, respectively. Natural soil was included as a control and exhibited minimal nutrient removal. Ammonia, which may be recovered as fertilizer for drop fields in a soil-water-waste nexus, was generated by all three green sorption media mixes, therefore indicating their potential for use as soil amendments in agricultural and forested land after engineering filter applications. The kinetics analysis indicated that nitrate adsorption follows pseudo-first-order kinetics, while phosphate adsorption follows pseudo-second-order kinetics. The Gibbs free energy indicated that most of the adsorption reactions proceeded as exothermic. Lastly, a few equilibrium models, including the Langmuir, Freundlich, First Modified Langmuir, Temkin, Jovanovic, and Elovich models, were ranked and three were selected for use with IFGEM, AGEM-1, and AGEM-2, respectively, as below: (1) Langmuir, (2) Freundlich, and (3) First Modified Langmuir, according to three indices.

Indoor biomass burning is a major contributor to the emission of PAHs (polycyclic aromatic hydrocarbons) in China. To date, estimates of PAH emissions from the burning of biomass have involved considerable uncertainty, mostly from the lack of real-world measurements of emission factors. In this study, we conducted a comprehensive evaluation on PAH emissions from biomass burning in real-world cooking stoves in three Chinese provinces. PAH emission factors, in both particle- and gas-phase, from 11 fuel-stove combinations were measured and the provincial emissions were estimated based on the measured emission factors and fuel consumption. The measured PAH₂₈ emission factors (including 16 US EPA priority PAHs and 12 non-priority PAHs) ranged from 42 mg/kg to 370 mg/kg, with an order of magnitude difference, which was mostly affected by fuel type. The emission factors measured in this study were generally higher than those reported in laboratory studies and were comparable with field studies. The gas-particle distribution indicated that the absorption of PAHs by organic carbon in particulate matter (PM) was the dominant sorption mechanism in gas-particle distribution. The composition profile was different from previous studies, especially for non-priority PAHs, which are highly toxic and should be given more attention. Following the disparities in composition profiles, our study suggests that source apportionment based on single- or multi-diagnostic ratios may lead to large bias and uncertainties. It appears that the toxicity potential of PAHs in northern China emitted from combustion of crop residues is greater than that in southern China where PAHs are mainly emitted from wood combustion.

Volcanic eruptions are important components of natural disturbances that provide a model to explore the effects of volcanic eruption disturbances on soil microorganisms. Despite widespread research, to the best of our knowledge, no studies of volcanic eruption disturbances have investigated the effects on soil microbial communities in the montane meadow steppe. To address this gap, we meticulously investigated the characteristics of the soil microbial communities from the volcano and steppe sites using Illumina MiSeq high-throughput sequencing. Hierarchical clustering analysis and principal coordinate analysis (PCoA) showed that the soil microbial communities from the volcano and steppe sites differed. The diversity and richness of the soil microbial communities from the steppe sites were significantly higher than at the volcano sites (P < 0.05), and the soil microbial communities in the steppe sites had higher stability. The effects of volcanic eruption disturbances on the bacterial community development are greater than its effects on the fungal communities. The environmental filtering of volcanic eruptions selectively retained some special microorganisms (i.e., Conexibacter, Agaricales, and Gaiellales) with strong adaptability to the environmental disturbances, enhanced metabolic activity for sodium and calcium reabsorption, and increased relative abundances of the lichenized saprotrophs. The soil microbial communities from the volcano and steppe sites cooperate to form complex networks of species interactions, which are strongly influenced by the interaction of the soil and vegetation factors. Our findings provide new information on the effects of volcanic eruption disturbances on the soil microbial communities in the montane meadow steppe.

A microcosm experiment was carried out to study the ecotoxicity and interactions between heavy metals and polyvinyl chloride microplastics. Fifteen treatments were tested and results were examined after one month. In details, this work aims to study the ecotoxicological effects of cadmium (10 and 20 mg kg⁻¹ Dry Weight DW), polyvinyl chloride (PVC) and its modified forms; PVC-DETA (PD) and PVC-TETA (PT) (20 and 40 mg kg⁻¹ DW), separately and in mixtures, on meiofauna from Bizerte lagoon (NE Tunisia) with focus on nematode features. The results obtained showed that individual treatments were toxic for meiofauna and particularly for free-living nematodes. No clear trends characterized the numerical responses but significant reductions were observed for diversity indices. Moreover, the binary combinations of contaminants have a lesser toxic effect compared to their individual effects. This effect could be related to the high-capacity chelating ability of PVC and its polymers against cadmium.

Long-term CO₂ and PM₂.₅ measurements in urban areas have important impacts on understanding the roles of urbanization in climate change and air pollution. From 2009 to 2017, CO₂ fluxes were measured by the eddy covariance (EC) system at a height of 140 m on the Beijing Meteorological Tower. The CO₂ fluxes followed a typical two-peak diurnal pattern all year round. The PM₂.₅ concentrations followed a similar diurnal pattern as the CO₂ fluxes in summer but a different diurnal pattern in winter (low in the day and high at night). On a seasonal time scale, both the CO₂ fluxes and the PM₂.₅ concentrations showed a pronounced seasonal variation (high in winter and low in summer). The spatial variations in CO₂ fluxes were dominated by the prevailing land use types within the flux footprint, particularly dense residential areas and heavy traffic roads. On both diurnal and annual time scales, the urban underlying surface was a net source of CO₂. The 9-year average annual total CO₂ flux was 36.4 kg CO₂·m⁻² yr⁻¹. Depending on the yearly prevailing wind direction, the effect of the heterogeneity correction on the annual total CO₂ fluxes based on the gap-filled dataset could reach up to 3.5%. Over the 9-year period, both the CO₂ fluxes and the PM₂.₅ concentrations exhibited a declining interannual trend, and CO₂ fluxes could account for 64% of the interannual variability in PM₂.₅ concentrations. In summer, emissions were more likely to control the interannual variability in PM₂.₅ concentrations, whereas in winter, meteorological conditions had a greater impact on the interannual variability in PM₂.₅ concentrations.