We have carried out a comprehensive analysis of six air pollutants (particles with an aerodynamic diameter less than 2.5 μm (PM₂.₅) and less than 10 μm (PM₁₀), carbon monoxide (CO), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), and ozone (O₃)) in western China, including the spatiotemporal characteristics of air pollutants, their relationship with meteorological factors and emission sources, and the efficiency of emission control strategies for the region. Based hourly observations at 23 sites in western China from June 2016 to May 2017, concentrations of most pollutants were higher outside the Tibetan Plateau, lowest in summer and highest in winter, the exception being O₃. This was partially because meteorological conditions in winter were found to the most unfavorable to pollutant dispersion and dilution than other seasons. Pollutant concentrations at most sites were correlated with the residential emissions which were higher in winter, but anti-correlated with the industrial emissions which were lower during the winter holiday period. The Weather Research and Forecasting with Chemistry (WRF-Chem) simulations of four pollution control strategies indicated that reduction of residential emissions is crucial to alleviate PM₂.₅, PM₁₀, and CO pollution in western China, although reduction of industrial and transport emissions can reduce SO₂ and NO₂, respectively. Since PM₂.₅ and PM₁₀ were also found to be the species most and next frequently responsible for extremely serious pollution in western China, respectively, we recommend pollution control regulations that target residential emissions.

Applications of aluminium (Al) salt or lanthanum (La) modified bentonite (LMB) have become popular methodologies for immobilizing phosphorus (P) in eutrophic lakes. The presence of humic substances, has been shown to inhibit this form of treatment due to the complexation with La/Al. However, the effects of other dissolved organic matter (DOM), especially that derived from phytoplankton (the dominant source in eutrophic lakes) are unknown. In this study, the interaction with La/Al of Suwannee River Standard Humic Acid Standard II (SRHA) and algae-derived DOM (ADOM) were investigated and compared. Differed to SRHA which was dominated by polyphenol-like component (76.8%, C1-SRHA), majority in ADOM were protein-like substance, including 41.9% tryptophan-like component (C2-ADOM) and 21.0% tyrosine-like component (C3-ADOM). Two reactions of complexation and coprecipitation were observed between SRHA/ADOM and La/Al. Complexation dominated at low metal inputs less than 10 μM and coprecipitation was the main reaction at higher metal inputs. For ADOM, the tryptophan-like component (C2-ADOM) was the important component to react with metal. The reaction rate for C2-ADOM with La were about two-third of that for C1-SRHA, indicating that the influence of C2-ADOM was significant during the P immobilization by La/Al-based treatment in eutrophic lakes. The P removal data in the presence of ADOM confirmed the significant inhibition of ADOM. In addition, based on the composition of coprecipitates and relatively biodegradable character of tryptophan-like substances (C2-ADOM), the coprecipitation of ADOM was assumed to reduce the stability of precipitated P in eutrophic lakes. The release of P from the potential biodegradation of the coprecipitates and thus the possible decline of the performance of P immobilization by La/Al-based treatments is an important work in the future.

The present study deals with the cyto-genotoxicological impact of ionic liquids, 1-butyl-3-methylimidazolium bromide, trihexyl tetradecylphosphonium dicyanamide, 1-decyl-3-methylimidazolium tetrafluoroborate, benzyldimethyltetradecylammonium chloride, and 1-butyl-4-methylpyridinium chloride, on animal cells and their biodegradation. The long alkyl chain containing ionic liquids were found to be more toxic whereas benzene functional group in benzyldimethyltetradecylammonium chloride enhances its toxicity. Aerobic bacterial granules, a bacterial consortium, were developed that have promising ability to break down these organic pollutants. These aerobic bacterial granules have been applied for the biodegradation of ionic liquids. The biological oxygen demand (5 days) and chemical oxygen demand parameters confirmed that the biodegradation was solely due to aerobic bacterial granules which further decreased the time period needed for regular biodegradation by biological oxygen demand (28 days). The high resolution mass spectrometry analysis further approved that the degradation of ionic liquids was mainly via removal of the methyl group. Elevated N-demethylase enzyme activity supports the ionic liquids degradation which may be occurring through demethylation mechanism. The amplicon sequencing of aerobic bacterial granules gives insight into the involvement of the bacterial community in the biodegradation process.

In modern society, the intense vehicle traffic and the lack of effective mitigating strategies may adversely impact freshwater systems. Road-deposited sediments (RDS) accumulate a variety of toxic substances which are transported into nature during hydrologic events, mainly affecting water bodies through stormwater runoff. The aim of this study was to evaluate the RDS metal enrichment ratio between the end of wet season and the middle of the dry season for Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn in samples from Natal, Brazil. Twenty RDS, drainage system and river sediment samples were collected in the wet and dry seasons using a stainless-steel pan, brush and spatula. In the laboratory, the samples were submitted to acid digestion and heavy metal concentrations were measured by atomic absorption spectrometry (AAS). A consistent RDS enrichment by heavy metals in dry season samples was followed by an increase in the finest particle size fraction (D < 63 μm). Maximum concentrations were 5, ND, 108, 23810, 83, ND, 77 and 150 mg kg⁻¹ for Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn, respectively. The RDS enrichment ratio was Cr(1.3 ×), Cu(2.6 ×), Fe(3.3 ×), Mn(1.5 ×), Pb(1.5 ×) and Zn(2.1 ×). The Geo-accumulation Index values showed that RDS were moderately polluted for Cu and slighted polluted for Zn and Pb. Principal Component Analysis (PCA) showed that the accumulation of toxic heavy metals decreased according to water flow.

Atmospheric aerosols have been found to influence the development of planetary boundary layer (PBL) and hence to aggravate haze pollution in megacities. PBL height (PBLH) determines the vertical extent to which the most pollutant effectively disperses and is a key argument in pollution study. In this study, we quantitatively evaluate aerosol radiation effect on PBL, as well as assessment of surface cooling effect and atmosphere heating effect. All the data are measured at a site of Beijing from 2014 to 2017, of which PBLH is retrieved from micro pulse lidar and aerosol optical depth (AOD) from sunphotometer. Case study shows qualitatively that relative high aerosol load reduces PBLH, and in turn causes a high surface PM₂.₅ concentration. We preliminarily reveal the influential mechanism of aerosol on PBL. The influence of aerosol on the radiation flux of PBL is analyzed, with the correlation coefficient (R) of 0.938 between AOD and radiative forcing of BOA (RFBOA) and R = 0.43 between RFBOA and PBLH. Also, AOD is found to negatively correlate with PBLH (R = −0.41). With the increase of AOD, the cooling effect of surface is enhanced, and further impede the development of PBL. Due to aerosol-induced reduction of PBLH, near surface PM₂.₅ concentration surges and presents an exponential growth following AOD. Then, it is speculated and testified that the relationship between SSA (single scatting albedo) and PBLH would be determined by the location of absorbing aerosol within PBL. The upper PBL absorbing aerosol may decrease PBLH, while the lower absorbing aerosol appear to enhance PBLH. The study probably can provide effective observational evidence for understanding the effect of aerosol on PBL and be a reference of air pollution mitigation in Beijing and its surrounding areas.

The contamination with antibiotic resistance genes (ARGs) in raw drinking water source may pose a direct threat to human health. In this study, metagenomics sequencing and analysis were applied to investigate the ARG pattern in 12 drinking water sources in upper and middle reach of Huaihe River Basin, China. Based on the redundant analysis and multi-linear regression model, location, specific microbial taxa, number of livestock and health facilities significantly influenced the ARG profile in drinking water sources. Besides the cluster effect of ARG in samples from plain and bedrock mountain areas, the samples from fracture aquifer areas also showed a distinctive biogeographic pattern with that from porous aquifer areas. Putative ARGs host Opitutus and Flavobacterium were the enriched biomarkers in plain and fracture aquifer area respectively, which mainly carried bacitracin, multidrug, beta-lactam and tetracycline ARGs. This result illuminated that both natural background and anthropogenic activities in the watershed influenced the ARG profile in natural freshwater system significantly. The low MGEs abundance and absence of pathogen revealed a low ARG dissemination risk in sampled drinking water sources, while Polynucleobacter was an abundant ARGs host and was significantly related to the ARG profile, which indicated that specific bacteria was responsible for ARGs propagation and accumulation in surface freshwater system. Further researches are needed to assess human exposure to raw drinking water source and the potential risk, as well as the species interaction in microbial community and its impact on ARG propagation under oligotrophic condition.

In this study, a multi-component catalyst, β-cyclodextrin (β-CD) and reduced graphene oxide (rGO) co-modified Fe₃O₄, was fabricated via one-pot solvothermal method and used as a synergistic catalyzer for Bisphenol A (BPA) removal. The study found that catalytic reactions of BPA followed the pseudo-first-order kinetics model, and the correlation rate constants (kₒbₛ) were calculated. Compared with Fe₃O₄@β-CD (0.02173 min⁻¹), Fe₃O₄/rGO (0.09735 min⁻¹) and Fe₃O₄ (0.01666 min⁻¹), the composite (0.15733 min⁻¹) exhibited stronger catalytic ability to remove BPA from aqueous solution under the same conditions, which were attributed to the synergistic enhancement effect among the components. The introduction of rGO in the composites was beneficial to the generation of •OH, and the role of β-CD might enhance the utilization of •OH. A possible three-element catalytic schematic diagram was described. The effects of pH, dosage of the catalyst, initial H₂O₂ and NH₂OH concentrations on the removal efficiency were further investigated. The removal of BPA and TOC retained 78.2 ± 2.4% and 52.9 ± 2.5% after five cycles, indicating its excellent stability and reusability. Furthermore, a probable reaction pathway of BPA removal was suggested by analyzing the intermediate products. All results indicated that the composite had high and stable catalytic performance, which made it have potential application on the industrial treatment of wastewater.

Metal contamination in aquatic environments is a severe global concern to human health and aquatic ecosystems. This study used several risk assessment indices, to evaluate metal (Cu, Zn, Pb, Cd and Cr) environmental risk of riverine surface sediments across the rural-urban interface of the rapidly developing Wen-Rui Tang River watershed in eastern China. Risk assessments were determined for 38 sites based on the potential ecological risk index (RI), consensus-based sediment quality guidelines (SQGs) and risk assessment code (RAC). Land-use cluster analysis showed that sediments were severely contaminated, especially for Cd, whose concentrations were ∼100 times higher than background levels and had a high proportion in the bioaccessible fraction. According to RI, ErCd was identified with extremely high risk potential, resulting in the highest ecological risk of Cluster 4 (industrial). Similarly, risk within Cluster 4 (industrial) was also ranked highest by SQGs assessment due to the high proportion of industrial land use. Zinc was determined with high risk due to its high concentration compared to its effect range medium (ERM) value. Discrepancies in predicting environmental risks from metals among the three indices were mainly attributed to the contrasting definitions of these metrics. Environmental risk uncertainty derived from spatial variation was further estimated by Monte Carlo simulation and ranked as: Zn > Cd > Cr > Pb > Cu. This comprehensive environmental risk assessment provides important information to guide remediation strategies for management of metal contamination at the watershed scale.

Organic aerosol (OA) are always the most abundant species in terms of relative proportion to PM₂.₅ concentration in Beijing, while in previous studies, poor link between carbonaceous particles and their gaseous precursors were established based on field observation results. Through this study, we provided a comprehensive analysis of critical carbonaceous species in the atmosphere. The concentrations, diurnal variations, conversions, and gas-particle partitioning (F-factor) of 8 carbonaceous species, carbon dioxide (CO₂), carbon monoxide (CO), methane (CH₄), volatile organic compounds (VOCs), non-methane hydrocarbon (NMHC), organic carbon (OC), elemental carbon (EC), and water soluble organic compounds (WSOCs), in Beijing were analyzed synthetically. Carbonaceous gases (CO, CO₂, VOCs, and CH₄) and OC/EC ratios exhibited double-peak diurnal patterns with a pronounced midnight peak, especially in winter. High correlation between VOCs and OC during winter nighttime indicated that OC was formed from VOCs precursors via an unknown mechanism at relative humidity greater than 50% and 80%, thereby promoting WSOC formation in PM₁ and PM₂.₅ respectively. The established F-factor method was effective to describe gas-to-particle transformation of carbonaceous species and was a good indicator for haze events since high F-factors corresponded with enhanced PM₂.₅ level. Moreover, higher F-factors in winter indicated carbonaceous species were more likely to exist as particles in Beijing. These results can help gain a comprehensive understanding of carbon cycle and formation of secondary organic aerosols from gaseous precursors in the atmosphere.

Polycyclic aromatic hydrocarbons (PAHs) and aliphatic hydrocarbons (AHs), including petroleum biomarkers, were studied in four sediment cores collected around Deception and Penguin Islands, Antarctica. Total PAHs in Deception Island (DCP) samples ranged from 2.0 to 26.8 ng g⁻¹, and in Penguin Island (PGI) varied between 13.2 and 60.3 ng g⁻¹. Multiple sources of PAHs were verified in DCP, with petrogenic-derived compounds being predominant over the last 10 years. In PGI, PAHs related to natural contributions from the erosion of coal deposits were reported. Total AHs in DCP ranged from 4.5 to 19 μg g⁻¹ and in PGI varied between 5.3 and 21.9 μg g⁻¹. In DCP, the n-alkanes distribution pattern showed the presence of petroleum residues in the top sections and both terpanes and hopanes were detected, related to the use of fossil fuels for power generation and in different types of vessels. In PGI, the main source of n-alkanes was marine inputs and only terpanes were detected. The slight increase in hydrocarbon levels observed from 1980 onward in DCP was assumed to be due to the development of tourism in the region and to the scientific station activities. In PGI, anthropogenic-related hydrocarbons were detected in the recent sections and were linked to the development of tourism near the island, scientific activities and the increase in vessel traffic. In general, the concentrations of hydrocarbons found around both islands were comparable to those found in uncontaminated Antarctic regions.