Quinone is the important redox functional group for electron transfer capacity (ETC) of humic acid (HA). Lignin, as major component in corn straw, can be decomposed into phenol monomers, then oxidation into quinones for synthesis of HA during composting process. However, it is still unclear that the effects of type and variation characteristics of phenol monomers on redox characteristics of HA during straw composting process. In this study, p-hydroxybenzoic acid (P1), vanillic acid (P2), syringic acid (P3), p-hydroxy benzaldehyde (P4), 4-coumaric acid (P5), 4-hydroxyacetophenone (P6), ferulic acid (P7) and 4-hydroxy-3-methylacetophenone (P8) were recognized and clustered into three groups. The concentration of polyphenol presented a significant downward trend during the straw composting process. Based on the relationships among phenol monomers to ETC, electron donating capacity (EDC), electron accepting capacity (EAC) and quinone, we found that P1, P2, P3, P5 and P7 were significantly related to ETC, EDC and EAC of HA (P < 0.05). Furthermore, NH₄⁺-N and NO₃⁻-N were the main micro-environmental factors linking to ETC-related phenol monomers and redox characteristics of HA in straw composts (P < 0.05). Finally, two groups of core microflora that promoting the ETC-related phenol monomers and NH₄⁺-N, and ETC-related phenol monomers and NO₃⁻-N were identified by Mantel test, respectively. This study contributes a new insight for polyphenol way for redox capacity of HA in traditional composting and utilization of straw compost in contaminated environments.

Hemocytes are the main immune cells in bivalve mollusks and one of the sensitive targets for nanoparticle toxicity. Bivalve hemocytes consist of multiple functional heterogeneous cell types, but their different roles in immune system against foreign particles remain largely unknown. In order to clarify the different immune responses of hemocyte subpopulations to silver nanoparticles (AgNPs) and Ag ions, in this study, the Hong Kong oyster (Crassostrea hongkongensis) hemocytes were employed and separated into three subpopulations based on their cell size and granularity, including agranulocytes (R1), semigranulocytes (R2), and granulocytes (R3). We first demonstrated that AgNPs could rapidly enter into the oyster hemocytes within 3 h by phagocytosis process and resulted in different immune responses in hemocyte subpopulations. The most affected cell subtype by AgNPs was the granulocytes, followed by semigranulocytes, whereas agranulocytes were not affected following exposure to AgNPs. Interestingly, AgNPs induced the granule formation in semigranulocytes and further increased the proportion of granulocytes, whereas their ionic counterparts had no such effects on hemocyte composition, indicating the different detoxification mechanisms for nanoparticulate and ionic form. Following AgNP exposure, the dissolved Ag ions were accumulated in lysosomes and caused lysosomal dysfunction, indicating that lysosomes were the main targets for AgNP toxicity and the dissolved Ag ions were the main contributor of AgNP toxicity. Furthermore, AgNP exposure induced reactive oxygen production and impeded the lysosome function and phagocytosis in granulocytes, with impaired immunity system in oysters. Our study identified the different immune responses of oyster hemocyte subpopulations to AgNPs based on the in vitro short-term exposure assays, which may be applied to rapidly evaluate the ecotoxicological risks of different nanoparticles in aquatic systems.

Rapid urbanization and the aggregation of human activities in cities have resulted in large amounts of anthropogenic heat (AH) emission, which affects urban climate. Quantifying and assessing the AH emission values accurately and analyzing their spatial distribution characteristics is important to understand the energy exchange processes of urban areas. In this study, the high spatial resolution anthropogenic heat flux (AHF) quantification and spatial distribution analysis were conducted using multi-source data in the Beijing-Tianjin-Hebei region (BTH region) of China. First, the AH emission in district and city level were estimated using inventory method based on energy consumption and socio-economic statistical data; Then, AHF spatial quantification models were constructed based on high spatial resolution nighttime light (NTL) data and Point of interests (POI) data, and 130 m × 130 m gridded AHF quantification result in BTH region was realized; Finally, the potential numerical and spatial distribution patterns of AHF were analyzed using various indicators including contribution rate and aggregation index. The results show that: (1) The parameterized index constructed based on NTL and POI data shows a strong correlation with AHF, with R² ranging from 0.79 to 0.94 and a mean absolute error (MAE) value of 0.72 w·m⁻², which can be applied to the quantification of gridded AHF values with high resolution. The highest total AHF in the study area is 214 w·m⁻², and the average value is 2.24 w·m⁻². (2) Considering the sources of AHF, industrial emission sources in BTH region contribute the most to the total AHF, but commercial building emission sources in Beijing have a higher contribution, which can reach 33.8%. (3) Different types of AHF have different spatial aggregation levels. Commercial building emission and human metabolic emission have the highest aggregation level, and transportation emission has the lowest aggregation level.

Hot moments of nitrous oxide (N₂O) emissions induced by interactions between weather and management make a major contribution to annual N₂O budgets in agricultural soils. The causes of N₂O production during hot moments are not well understood under field conditions, but emerging evidence suggests that short-term fluctuations in soil oxygen (O₂) concentration can be critically important. We conducted high time-resolution field observations of O₂ and N₂O concentrations during hot moments in a dryland agricultural soil in Northern China. Three typical management and weather events, including irrigation (Irr.), fertilization coupled with irrigation (Fer.+Irr.) or with extreme precipitation (Fer.+Pre.), were observed. Soil O₂ and N₂O concentrations were measured hourly for 24 h immediately following events and measured daily for at least one week before and after the events. Soil moisture, temperature, and mineral N were simultaneously measured. Soil O₂ concentrations decreased rapidly within 4 h following irrigation in both the Irr. and Fer.+Irr. events. In the Fer.+Pre. event, soil O₂ depletion did not occur immediately following fertilization but began following subsequent continuous rainfall. The soil O₂ concentration dropped to as low as 0.2% (with the highest soil N₂O concentration of up to 180 ppmv) following the Fer.+Pre. event, but only fell to 11.7% and 13.6% after the Fer.+Irr. and Irr. events, which were associated with soil N₂O concentrations of 27 ppmv and 3 ppmv, respectively. During the hot moments of all three events, soil N₂O concentrations were negatively correlated with soil O₂ concentrations (r = −0.5, P < 0.01), showing a quadratic increase as soil O₂ concentrations declined. Our results provide new understanding of the rapid short response of N₂O production to O₂ dynamics driven by changes in soil environmental factors during hot moments. Such understanding helps improve soil management to avoid transitory O₂ depletion and reduce the risk of N₂O production.

Although cadmium (Cd) is a toxic heavy metal that reportedly causes liver injury, few studies have investigated biomarkers of Cd-induced liver injury. The purpose of this study is to investigate the role of bile acid (BA) in Cd-induced liver injury and determine reliable and sensitive biochemical parameters for the diagnosis of Cd-induced liver injury. In this study, 48 Sprague-Dawley rats were randomly divided into six groups and administered either normal saline or 2.5, 5, 10, 20, and 40 mg/kg/d cadmium chloride for 12 weeks. A total of 403 subjects living in either a control area (n = 135) or Cd polluted area (n = 268) of Dongdagou-Xinglong (DDGXL) cohort were included, a population with long-term low Cd exposure. The BA profiles in rats' liver, serum, caecal contents, faeces, and subjects' serum were detected using high-performance liquid chromatography-tandem mass spectrometry (HPLC–MS/MS). Changes in rats' and subjects' liver injury indices, rats' liver pathological degeneration, and rats' liver and subjects’ blood Cd levels were also measured. Cadmium exposure caused cholestasis and an increase in toxic BAs, leading to liver injury in rats. Among them, glycoursodeoxycholic acid (GUDCA), glycolithocholic acid (GLCA), taurolithocholic acid (TLCA), and taurodeoxycholate acid (TDCA) are expected to be potential biomarkers for the early detect of Cd-induced liver injury. Serum BAs can be used to assess Cd-induced liver injury as a simple, feasible, and suitable method in rats. Serum GUDCA, GLCA, TDCA, and TLCA were verified to be of value to evaluate Cd-induced liver injury and Cd exposure in humans. These findings provided evidence for screening and validation of additional biomarkers for Cd-induced liver injury based on targeted BA metabolomics.

Construction workers on highway rehabilitation projects can be exposed to a combination of traffic- and construction-related emissions. To assess the personal exposure a worker experiences, a portable battery-operated Air Quality Device (AQD) was utilised to measure emissions during normal construction operations of a major road rehabilitation project. Emissions measured were nitrogen dioxide (NO₂), Total Volatile Organic Compounds (TVOCs) and Particulate Matter (PM₁₀, PM₂.₅, and PM₁). The objective of the paper is to document the hazardous emissions that construction workers may be exposed to and allow for a basis of informed decision making to mitigate the risks of a road construction project. Most critically, this article is designed to raise awareness of the potential impact to a worker's wellbeing as well as highlight the need for further research. Through statistical analysis, asphalt paving was identified as the most hazardous activity in terms of exposure relative to other activities. This activity was further assessed using discrete-time Markov chain Monte Carlo simulations with results indicating a high probability that workers may be exposed to greater hazardous emission concentrations than measured. Limiting the distance to the source of emissions, large-scale use of warm-mix asphalt and reducing the idling times of construction vehicles were identified as practical mitigation measures to reduce exposure and aid in achieving zero-harm objectives. Finally, it is found that males are more susceptible to long-term implications of hazardous emission inhalation and should be more aware if the scenarios they might work in expose them to this.

Extensive algal bloom in the surface water is a pressing issue in Lake Dianchi that causes lake restoration to be difficult owing to complex and variable phosphorus (P) sources in the water column. P released from algae, suspended particles (SS), and sediment can provide sustainable P sources for algal blooms. However, little is known regarding the dynamic of P speciation in these substances from different sources. In this study, solution ³¹P nuclear magnetic resonance (³¹P NMR) and chemical sequential extraction were employed to identify P speciation in algae, SS, and sediment during different periods. Results showed that dissolved inorganic P (Pᵢ) directly accumulated in algae in the form of orthophosphate (ortho-P) and pyrophosphate (pyro-P). Algae preferentially utilized Pᵢ, followed by organic P (Pₒ) in the water column when the Pᵢ was insufficient during growth and reproduction. The ³¹P NMR spectra demonstrated that ortho-P, orthophosphate monoesters (mono-P), orthophosphate diesters (diester-P), and pyro-P dominated the P compounds across the samples tested. Increasing remineralization of SS mono-P driven by intense alkaline phosphatase activities was caused by increasing P needs of algae and pressure of P supply in the water column. The higher ratios of diester-P to mono-P in sediment (mean 0.55) than those in algae (mean 0.07) and SS (mean 0.11 in surface water, 0.14 in bottom water) suggested that the degradation and regeneration occurred within these P compounds during or after sedimentation. Pᵢ content in algae during growth and reproduction was controlled by its P absorption and utilization strategies. Results of this study provide insights into the dynamic cycling of P in algae, SS, and sediment, explaining the reason for algal blooms in the surface water with low concentrations of dissolved P.

Fine particulate matter (PM₂.₅) has been associated with risk of oral and respiratory diseases. However, the biological mechanisms of adverse oral and respiratory health response to PM₂.₅ fluctuation have not been well characterized. This study aims to explore the relationships of PM₂.₅ with airway inflammation, salivary biomarkers and buccal mucosa microbiota. We performed a panel study among 40 college students involving 4 follow-ups from August to October 2021 in Hefei, Anhui Province, China. Health outcomes included fractional exhaled nitric oxide (FeNO), salivary biomarkers [C-reactive protein (CRP), cortisol, lysozyme and alpha-amylase] and buccal mucosa microbial diversity. Linear mixed-effect models were applied to explore the cumulative impacts of PM₂.₅ on health indicators. PM₂.₅ was positively correlated with FeNO, CRP, cortisol and alpha-amylase, while negatively with lysozyme. Per 10-μg/m³ increase in PM₂.₅ was linked to maximum increments in FeNO of 10.71% (95%CI: 2.01%, 19.41%) at lag 0–24 h, in CRP of 7.10% (95%CI: 5.39%, 8.81%) at lag 0–24 h, in cortisol of 1.25% (95%CI: 0.44%, 2.07%) at lag 0–48 h, and in alpha-amylase of 2.12% (95%CI: 0.53%, 3.71%) at lag 0–24 h, while associated with maximum decrement in lysozyme of 0.53% (95%CI: 0.12%, 0.95%) at lag 0–72 h. Increased PM₂.₅ was linked to reduction in the richness and evenness of buccal microbe and o_Bacillales and o_Bacteroidales were identified as differential microbes after PM₂.₅ inhalation. Bio-information analysis indicated that immunity system pathway was the most important enriched abundant process altered by PM₂.₅ exposure. In summary, short-term PM₂.₅ exposure may impair oral and respiratory health by inducing inflammatory and stress responses, weakening immune function and altering buccal mucosa microbial diversity.

Dissimilatory arsenate-respiring prokaryotes (DARPs) are considered to be the major drive of the reductive mobilization of arsenic from solid phases. However, it is not fully understood how phosphate, a structural analog of arsenate, affects the DARPs-mediated arsenic mobilization. This work aimed to address this issue. As-contaminated soils were collected from a Shimen Realgar Mine-affected area. We identified a unique diversity of DARPs from the soils, which possess high As(V)-respiring activities using one of multiple small organic acids as the electron donor. After elimination of the desorption effect of phosphate on the As mobilization, the supplement of additional 10 mM phosphate to the active slurries markedly increased the microbial community-mediated reductive mobilization of arsenic as revealed by microcosm tests; this observation was associated to the fact that phosphate significantly increased the As(V)-respiratory reductase (Arr) gene abundances in the slurries. To confirm this finding, we further obtained a new DARP strain, Priestia sp. F01, from the samples. We found that after elimination of the chemical effect of phosphate, the supplement of 10 mM phosphate to the active slurries resulted in an 82.2% increase of the released As(III) in the solutions, which could be contributed to that excessive phosphate greatly increased the Arr gene abundance, and enhanced the transcriptional level of arrA gene and the bacterial As(V)-respiring activity of F01 cells. Considering that phosphate commonly coexists with As in the environment, and is a frequently-used fertilizer, these findings are helpful for deeply understanding why As concentrations in contaminated groundwater are dynamically fluctuated, and also provided new knowledge on the interactions between the biogeochemical processes of P and As.

Recycling of electronic waste (e-waste) and inevitable pollution under current technology have always been a concern of people. Generation and release of pollutants in the recycling process of e-waste are closely related to processing technology and equipment. In this paper, the pollution characteristics of different functional areas and critical processing units in formal e-waste dismantling base have been studied systematically and comprehensively. The results showed that the overall pollutants concentration in crushing workshop and cathode ray tube (CRT) monitor disposing workshop are much higher than other functional areas. Screen-cone glass separation for CRT monitor was the processing unit with the greatest exposure risk and the hazard index (HI) of Pb was 4.60. Pollutant emission factor of the main processing units was calculated and the waste printed circuit board (WPCB) crushing was the most polluted unit. Appropriate improvements in technology and equipment can effectively reduce the generation and release of pollutants. Some reasonable prospects about intelligent equipment and special technologies were proposed for e-waste disposal. All the results provided theoretical and data support for pollution control and technology upgrade of the formal e-waste dismantling base.