Plastic debris provides a stable substrate and novel ecological niche for microorganisms in the aquatic environment, which was referred to as “Plastisphere”. Little is known about distribution patterns and responses of ecological function and structure of microbial communities in the plastisphere along rivers which usually have antibiotics pollution gradient. In this study, the differences in the community structure between the plastisphere and the planktonic bacteria, and their spatial variation of the community structure and function along a river with increased antibiotics pollution gradient was investigated at the watershed scale. The diversity of bacteria colonized on most plastic debris was higher than in surrounding water. Plastic debris could accumulate a higher abundance of some potential pathogens than surrounding water even at high antibiotics concentrations. The source tracking results showed that downstream plastisphere inherited much higher proportions of bacterial taxa from upstream than planktonic bacteria. About 92.3–99.7% of bacteria communities in downstream water were not from upstream but from the input of downstream human activities. On the contrary, high proportions of bacterial taxa in downstream plastisphere were closely connected to upstream. The plastisphere possesses higher ecological functional diversity than the planktonic bacteria. Seventy nine functional groups across plastisphere were predicted using functional annotation of prokaryotic taxa and only 65 functional groups were found in the planktonic bacteria. Plastisphere also acts as hotspot for biogeochemical cycling of nutrients such as N and S. Intensive human activities of urban and downstream agriculture and aquaculture had great effects on microbial community structure and functional groups of the Urumqi River. Pastisphere communities are much more resistant to human disturbance than planktonic bacteria. Compared to surrounding water, plastisphere increased inheritance from upstream microbial structure and function and also increased survival and propagation of pathogens in the downstream water with high concentrations of antibiotics.

In recent years, implementation of aggressive and strict clean air policies has resulted in significant decline in observed PM₂.₅ concentration in the Beijing–Tianjin–Hebei (BTH) region and its surrounding areas (i.e., the “2 + 26” region). To eliminate the effects of interannual and seasonal meteorological variation, and to evaluate the effectiveness of emission abatement policies, we applied a boosted regression tree model to remove confounding meteorological factors. Results showed that the annual average PM2.5 concentration normalized by meteorology for the “2 + 26” region declined by 38% during 2014–2019 (i.e., from 96 to 60 μg/m³); however, the BTH region exhibited the most remarkable decrease in PM₂.₅ concentration (i.e., a 60% reduction). Certain seasonal trend in normalized PM₂.₅ level remained for four target subregions owing to the effects of anthropogenic emissions in autumn and winter. Although strong interannual variations of meteorological conditions were unfavorable for pollutant dispersion during the heating seasons of 2016–2018, the aggressive abatement policies were estimated to have contributed to reductions in normalized PM₂.₅ concentration of 19%, 10%, 19%, and 17% in the BTH, Henan, Shandong, and Shanxi subregions, respectively. Our study eliminated the meteorological contribution to concentration variation and confirmed the effectiveness of the implemented clean air policies.

The process of anaerobic digestion in food waste treatment plants generates a large amount of volatile organic compounds (VOCs). Long-term exposure to this exhaust gas can pose a threat to the health of workers and people living nearby. In this study, VOCs emitted from different working units in a food waste anaerobic digestion plant were monitored for a year. Variations in VOCs emitted from each unit were analyzed and a health risk assessment was conducted for each working unit. The results show that the concentration of VOCs in different units varied greatly. The highest cumulative concentration of VOCs appeared in the hydrothermal hydrolysis unit (3.49 × 10⁴ μg/m³), followed by the sorting/crushing room (8.97 × 10³ μg/m³), anaerobic digestion unit (6.21 × 10² μg/m³), and biogas production unit (2.01 × 10² μg/m³). Oxygenated compounds and terpenes were the major components of the emitted VOCs, accounting for more than 98% of total VOC emissions. The carcinogenic risk in the plant exceeded the safety threshold (ILCR<1 × 10⁻⁶), while the non-carcinogenic risk was within the acceptable range (HI < 1). The carcinogenic risk from the hydrothermal hydrolysis unit was the highest, reaching 4.4 × 10⁻⁵, and was labeled as “probable risk.” The carcinogenic risk at the plant boundary was 1.2 × 10⁻⁵, indicating exhaust gases can cause a health threat to neighbors. Therefore, management VOCs in anaerobic digestion plants should receive more attention, and employees should minimize the time they spend in the hydrothermal hydrolysis unit.

The nutrient-rich effluent from wastewater treatment plants (WWTPs) constitutes a significant disturbance to coastal microbial communities, which in turn affect ecosystem functioning. However, little is known about how such disturbance could affect the community’s stability, an important knowledge gap for predicting community response to future disturbances. Here, we examined dynamics of coastal sediment microbial communities with and without a history of WWTP’s disturbances (named H1 and H0 hereafter) after simulated nutrient input loading at the low level (5 mg L⁻¹ NH₄⁺-N and 0.5 mg L⁻¹ PO₄³⁻-P) or high level (50 mg L⁻¹ NH₄⁺-N and 5.0 mg L⁻¹ PO₄³⁻-P) for 28 days. H0 community was highly sensitive to both low and high nutrient loading, showing a faster community turnover than H1 community. In contrast, H1 community was more efficient in nutrient removal. To explain it, we found that H1 community constituted more abundant and diversified r-strategists, known to be copiotrophic and fast in growth and reproduction, than H0 community. As nutrient was gradually consumed, both communities showed a succession of decreasing r-strategists. Accordingly, there was a decrease in community average ribosomal RNA operon (rrn) copy number, a recently established functional trait of r-strategists. Remarkably, the average rrn copy number of H0 communities was strongly correlated with NH₄⁺-N (R² = 0.515, P = 0.009 for low nutrient loading; R² = 0.749, P = 0.001 for high nutrient loading) and PO₄³⁻-P (R² = 0.378, P = 0.034 for low nutrient loading; R² = 0.772, P = 0.001 for high nutrient loading) concentrations, while that of H1 communities was only correlated with NH₄⁺-N at high nutrient loading (R² = 0.864, P = 0.001). Our results reveal the potential of using rrn copy number to evaluate the community sensitivity to nutrient disturbances, but community’s historical contingency need to be taken in account.

In the last decades, the use of organic ultraviolet-filters (UV-filters) has increased worldwide, and these compounds are now considered emerging contaminants of many freshwater ecosystems. The present study aimed to assess the effects of 3-(4-methylbenzylidene) camphor (4-MBC) on a freshwater invertebrate community and on associated ecological functions. For that, artificial streams were used, and a natural invertebrate benthic community was exposed to sediments contaminated with two concentrations of 4-MBC. Effects were evaluated regarding macroinvertebrate abundance and community structure, as well as leaf decomposition and primary production. Results showed that the macroinvertebrate community parameters and leaf decomposition rates were not affected by 4-MBC exposure. On the other hand, primary production was strongly reduced. This study highlights the importance of higher tier ecotoxicity experiments for the assessment of the effects of low concentrations of organic UV-filters on freshwater invertebrate community structure and ecosystem functioning.

Given the toxicity of metals, including aluminum (Al), and the effects of water temperature on ectotherms, we investigated the individual or association effect of these variables (Al + acidic pH + temperature changes) on sperm quality of Astyanax altiparanae. Mature males were divided into nine experimental groups based on the combination of each of three water temperatures (20, 25, and 30 °C) with neutral and acidic pH values (7.0 and 5.5, respectively) with or without 0.5 mg L⁻¹ Al. The fish were subjected to subacute, semi-static exposure and at 24 and 96 h were evaluated for seminal parameters: (1) pH; (2) osmolality; (3) sperm concentration; (4) sperm morphology; (5) sperm kinetics; and (6) sperm ultrastructure. At 30 °C, Al caused a reduction in osmolality (24 and 96 h) and sperm concentration (24 h). When analysing sperm kinetics (30 s post-activation), Al caused a reduction in total motility at all temperatures (24 h), and when this exposure time was longer (96 h), both acidic pH and Al addition to the water caused sperm motility reduction. By analysing curvilinear velocity (VCL) 30 s after sperm activation (24 and 96 h), the acidic pH caused a reduction in sperm movement at 20 and 30 °C, but at 25 °C Al triggered this reduction. Finally, Al in the water caused ultrastructural changes in the sperm head, midpiece, and flagella regardless of water temperature. Also, it was found that the combination of Al at 30 °C caused a reduction in sperm head area while at 20 °C, Al triggered a reduction in the midpiece area. Therefore, acidity influenced some A. altiparanae sperm parameters but Al in the water accentuated these effects on seminal quality, especially seminal osmolality and sperm concentration, kinetics, and ultrastructure. This toxicity was also influenced by changes in water temperature.

The occurrence of microplastics was investigated in water, sediment and fish from the Fengshan River system. All collected samples contained microplastics with 334–1058 items/m³ in the water samples, 508-3987 items/kg dry weight in the sediment samples and 14–94 items/fish in the fish samples. The spatial distribution of microplastics in water and sediments was attributed to anthropogenic discharges, flow dynamics, tidal exchanges and microplastic density. This was evidenced by significant correlations of microplastics with the river pollution index (RPI), chemical oxygen demand (COD), suspended solid (SS), flow velocity and the presence of different polymer types of microplastics in water and sediment. Microplastic abundance in fish was correlated to SS, pH and conductivity, indicating that these water quality variables might affect bioavailability of microplastics to fish. Concentrations of microplastics/cm length of demersal fish at a higher trophic level (Leiognathus equulus and Pomadasys argenteus) were higher than those of a benthopelagic fish (Oreochromis niloticus niloticus). The significant relationships observed suggest that collected fish might prefer to ingest long fibrous microplastics from sediments and large fragmented microplastics from water. The high levels of 3- and 4-ring polycyclic aromatic hydrocarbons (PAHs), particularly fluoranthene and pyrene, in fish muscle revealed that the collected fish species might have a high ability to accumulate these PAHs from food and the environment. Significant relationships between some PAHs in fish and microplastic abundances in water/sediments/fish suggested that these PAHs might be accumulated by fish from contaminated microplastics. This study provides unique information on the factors influencing the spatial distribution of microplastics and the role of microplastics on the accumulation of PAHs by fish.

In this study, an arsenic (As)-resistant facultative endophytic bacterial strain, F2, was isolated from the root of Oryza sativa Longliangyou Huazhan and identified as Serratia liquefaciens according to 16S rRNA gene sequence analysis. Strain F2 was characterized for i) its impacts on As immobilization in solution and rice tissue As accumulation, and ii) the mechanisms involved for different levels of As-pollution in soils. In strain F2-inoculated culture medium, the concentration of As decreased, while the pH, cell growth, and cell-immobilized As significantly increased over time. Grain As content reduced by between 23 and 36% in strain F2-inoculated rice plants in comparison to the control. Available As content decreased by between 28 and 52%, but unavailable As content increased by between 27 and 46% in the strain F2-inoculated soil when compared with the controls. Moreover, the strain decreased the As translocation factor by between 34 and 46%, but increased the As concentration by between 24 and 70% in Fe plaque on the rice root surfaces in comparison to the controls. These results suggested that strain F2 decreased the rice grain As uptake by i) decreasing available As in soil, ii) increasing rice root surface As adsorption, and iii) decreasing As translocation from the roots to grains. Our findings may provide a new rice-derived facultative endophytic bacteria-assisted approach for decreasing the As uptake to rice grains in As-polluted soils.

With increasingly severe air pollution, the aggravated health risks of particulate matter, especially ultrafine particles, are emerging as an urgent and sensitive topic. Considering the heterogeneity and complexity of ultrafine particles, there is insufficient evidence about their toxic effects and possible molecular mechanisms. To address this question, we analyzed the emission characteristics of quasi-ultrafine particles collected during winter in a typical coal-burning city, Taiyuan, and confirmed their contribution to lung cancer cell adhesion and metastasis. For the specific mechanism, we revealed that the endocytosis of quasi-ultrafine particles stimulated the release of HMGB1, induced NFκB-facilitated proinflammatory cytokine production through the interaction of HMGB1 with RAGE, and resulted in cancer-endothelial cell adhesion. These findings remind us of the potential effects of anthropogenic quasi-ultrafine particle pollution and provide a theoretical reference for the mitigation of tumorigenesis in a severe particulate matter contaminated environment.