There is growing evidence that the very presence of human beings in an enclosed environment can impact air quality by affecting the concentrations of certain airborne volatile organic compounds (VOC). This influence increases considerably when humans perform different activities, such as using toiletries, or simply eating and drinking. To understand the influence of these parameters on the concentrations of selected airborne constituents, a study was performed under simulated residential conditions in an environmentally-controlled exposure room. The human subjects either simply remained for a certain time in the exposure room, or performed pre-defined activities in the room (drinking wine, doing sport, using toiletries, and preparation of a meal containing melted cheese). The impact of each activity was assessed separately using our analytical platform and exposure room under controlled environmental conditions. The results showed that prolonged human presence leads to increased levels of isoprene, TVOCs, formaldehyde and, to a lesser extent, acetaldehyde. These outcomes were further supported by results of meta-analyses of data acquired during several internal studies performed over two years. Furthermore, it was seen that the indoor concentrations of several of the selected constituents rose when the recreational and daily living activities were performed. Indeed, an increase in acetaldehyde was observed for all tested conditions, and these higher indoor levels were especially notable during wine-drinking as well as cheese meal preparation. Formaldehyde increased during the sessions involving sport, using toiletries, and cheese meal preparation. Like acetaldehyde, acrolein, crotonaldehyde and particulate matter levels rose significantly during the cheese meal preparation session. In conclusion, prolonged human residence indoors and some recreational and daily living activities caused substantial emissions of several airborne pollutants under ventilation typical for residential environments.

This work has been conducted as an integrated approach to study the behavior of soils to the metals from sludge amendment. Bureau Commun Reference (BCR) methodology was used as an appropriate tool to harvest precious information about heavy metals evolution versus depth before and after sludge treatments. This three-step extraction procedure (i.e., BCR) may clarify the leaching or retention of heavy metals from the amended soils, as well as their risk level. Our results indicated that sludge applications has shown an increasing flux of heavy metals towards amended soils, of which Pb was the most abundant. Heavy metals mobility in control and amended soils showed that main influencing factors are pH and total organic carbon, especially for copper mobility. Almost all of the metals decreased with soil depth, except for Ni. Speciation of heavy metals in sludges showed that about 45% of Pb, Cu and Ni were associated with residual fraction; Cd was mainly bound to reducible fraction. Speciation forms in the control soil indicated that short term application of sludge has remobilized a fraction of heavy metals into their most labile forms (i.e., exchangeable and reducible fraction). Multivariate statistical analysis suggested that Cd, Zn, Pb and Cu preferentially accumulated in organic-rich surface horizons and clay layers where adsorption played an important role as a determining mechanism. Nevertheless, adsorption did not appear to be directly controlled by high pH values (pH > 7). From Cluster Analysis (CA), one can easily recognize that Pb, Zn and Cu movement in soil profiles were significantly affected by pH, especially residual fraction, labile fraction and reducible fraction.

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.

To simultaneously achieve biological denitrification and bio-energy recovery from sludge, the effects of nitrite on the two-phase anaerobic digestion (AD) of waste activated sludge were explored. Herein, effects of nitrite on the acidogenic phase are optimized, and the corresponding influence mechanisms are investigated. The experimental results show that the optimal nitrite treatment conditions for improving the acidogenic phase are an initial pH of 8.0, a nitrite addition concentration of 500 mg NO₂⁻-N·L⁻¹, and a fermentation time of six days. By comparing the effects of nitrite and nitrate on the acidogenic phase, it was found that it was the nitrite, not the nitrate, that significantly enhanced the sludge organic solubilization, hydrolysis, and acidification, which are primarily attributed to the redox property of nitrite. Based on an analysis of different forms of soluble nitrogen concentrations, there was no obvious accumulation of nitrite or nitrate during the acidogenic phase. An analysis of the methane production and the volatile solid (VS) degradation during the two-phase AD revealed that the nitrite improved the methane production from the methanogenic phase and enhanced the VS degradation of sludge during the entire two-phase AD process. These findings could provide references for simultaneously treating nitrite-rich wastewater and improving anaerobic sludge digestion via two-phase system.

Benzo [a]pyrene (BaP) is a well-known endocrine disruptor. Exposure to BaP is known to impair embryo implantation. The corpus luteum (CL), the primary source of progesterone during early pregnancy, plays a pivotal role in embryo implantation and pregnancy maintenance. The inappropriate luteal function may result in implantation failure and spontaneous abortions. However, the effect of BaP on CL remains unknown. This study investigated the deleterious effects of BaP on the structure and function of CL during early pregnancy. Pregnant rats were dosed with BaP at 0.2 mg.kg-1. d from day 1 (D1) to day 9 (D9) of gestation. We found that BaP reduced the number of CLs, disturbed the secretion of steroid and impacted the luteal vascular networks. BaP significantly decreased the angiogenesis factor (VEGFR, Ang-1 and Tie2) and increased the anti-angiogenic factor THBS1. Inhibited THBS1 function by LSKL partially rescued the angiogenesis defect caused by BaP. In vitro, BaP metabolite BPDE also interfered the expression levels of angiogenesis-related factors in HUVECs and impaired the angiogenesis, whereas supplemented with rAng-1 can alleviate the anti-angiogenic effect of BPDE. Furthermore, Notch signaling molecules, including Notch1, Dll4, Jag1 and Hey2, which are essential for the establishment and maturation of vascular networks, were affected by BaP exposure. Collectively, BaP broke the molecular regulatory balance between luteal angiogenesis and vascular maturation, impaired the construction of luteal vascular networks, and further affected luteal formation and endocrine function during early pregnancy. Our findings might provide new insight into the relationship between BaP and luteal insufficiency in early pregnancy. These data also give a new line of evidence for curtailing BaP emissions and protecting the women of childbearing age from occupational exposure.

Polycyclic aromatic hydrocarbons (PAHs) are formed by the incomplete combustion of fossil fuels and forest or biomass burning. PAHs undergo long-range atmospheric transport, as evidenced by in situ observations across the Arctic. However, monitored atmospheric concentrations of PAHs indicate that ambient PAH levels in the Arctic do not follow the declining trend of worldwide anthropogenic PAH emissions since the 2000s, suggesting missing sources of PAHs in the Arctic or other places across the Northern Hemisphere. To trace origins and causes for the increasing trend of PAHs in the Arctic, the present study reconstructed PAH emissions from forest fires in the northern boreal forest derived by combining forest carbon stocks and MODIS burned area. We examined the statistical relationships of forest biomass, MODIS burned area, emission factors, and combustion efficiency with different PAH congeners. These relationships were then employed to construct PAH emission inventories from forest biomass burning. We show that for some PAH congeners, for example, benzo[a]pyrene (BaP)—the forest-fire-induced air emissions are almost one order of magnitude higher than previous emission inventories in the Arctic. A global-scale atmospheric chemistry model, GEOS-Chem, was used to simulate air concentrations of BaP, a representative PAH congener primarily emitted from biomass burning, and to quantify the response of BaP to wildfires in the northern boreal forest. The results showed that BaP emissions from wildfires across the northern boreal forest region played a significant role in the contamination and interannual fluctuations of BaP in Arctic air. A source-tagging technique was applied in tracking the origins of BaP pollution from different northern boreal forest regions. We also show that the response of BaP pollution at different Arctic monitoring sites depends on the intensity of human activities.

This study analyzed fresh feces from three common bird species that live in urban environments and interact with human communities. Antibiotic resistance genes (ARGs) encoding resistance to three major classes of antibiotics (i.e., tetracyclines, β-lactams, and sulfonamides) and the mobile genetic element integrase gene (intI1) were abundant (up to 10⁹, 10⁸, 10⁹, and 10¹⁰ copies/g dry feces for tetW, blaTEM, sul1, and intI1, respectively), with relative concentrations surprisingly comparable to that in poultry and livestock that are occasionally fed antibiotics. Biomarkers for opportunistic pathogens were also abundant (up to 10⁷ copies/g dry feces) and the dominant isolates (i.e., Enterococcus spp. and Pseudomonas aeruginosa) harbored both ARGs and virulence genes. ARGs in bird feces followed first-order attenuation with half-lives ranging from 1.3 to 11.1 days in impacted soil. Although residual antibiotics were detected in the feces, no significant correlation was observed between fecal antibiotic concentrations and ARG relative abundance. Thus, other unaccounted factors likely contributed selective pressure for ARG maintenance. These findings highlight the contribution of wild urban bird feces to the maintenance and dissemination of ARGs, and the associated health risks.

Bifenthrin (BF) is a synthetic insecticide that is widely used in fields, resulting in an increase in its exposure to animals. However, reports on the toxic effects of BF on mammalian species and the underlying mechanism are still lacking. Here, we elucidated the mechanism underlying the toxic effects of BF on mouse reproduction using cell lines of immature mouse Leydig (TM3) and Sertoli (TM4) cells, which are constituent cells of testes. Our results show that BF suppressed the proliferation and viability of TM3 and TM4 cells. Additionally, treatment with BF induced cell cycle arrest, apoptotic cell death, and DNA fragmentation. Mitochondrial dysfunction and disruption of calcium homeostasis were observed in BF-treated TM3 and TM4 cells. Further, bifenthrin modulated unfolded protein response and mitochondrion-associated membrane and mitogen-activated protein kinase (MAPK)/phosphoinositide 3-kinase (PI3K) signaling pathways. The expression of the mRNAs related to cell cycle progression, steroidogenesis, and spermatogenesis was downregulated by BF, suggestive of testicular toxicity. Taken together, these results demonstrate the intracellular mechanism of action of BF to involve antiproliferative and apoptotic effects and testicular dysfunction in mouse testis.

Cattle-derived biochar (CB), which is derived from industrial pyrolysis of cattle carcasses in harmless treatment plants, is a naturally occurring mineral form of carbonate-bearing hydroxyapatite (CHAP) with a small amount of elemental carbon. CB has 4.02% of carbonate content, which falls under the B-type substitution of CHAP. In this work, the Cd(II) sorption capacity of CB was determined to be 0.82 mmol/g, with 97.6% of the Cd(II) uptake contributing to CHAP and only 2.36% of the Cd(II) uptake contributing to the elemental carbon component. The calculation and linear combination fitting (LCF) of Cd L₃-edge X-ray absorption near-edge structure (XANES) analysis indicated that the contributions of Cd(II) species to CB presented the following order: ion exchange (57.6%–61.0%) > precipitation (24.4%–29.9%) > surface complexation (12.5%–13.4%). The depth dependent X-ray photoelectron spectroscopy (XPS) showed the presence of ion exchange, which is accompanied by intraparticle diffusion. LCF of XANES and Rietveld analysis of X-ray diffraction (XRD) demonstrated that Cd(II) was precipitated in the form of Cd₅H₂(PO₄)₄·4H₂O on the CB surface. Furthermore, the precipitate was directly observed and identified by scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS). Consequently, we revealed the intricate binding mechanism of Cd(II) to CHAP-rich CB and confirmed the importance of surface precipitation.

The arsenic concentration is an important issue in compost production. The main inputs of a compost factory, including kerbsides, green wastes, food industry wastes, and river weeds are investigated in this study. Also, this study investigated how treated timbers, ashes, and other contamination can impact arsenic concentration in compost production. The results showed that most treated timbers and all ashes of treated and untreated timbers contained significant amounts of arsenic. These results revealed that the presence of a small amount of treated timber ashes can significantly increase the arsenic concentration in composts. The results of the study show the arsenic concentration in compost increase during cold months, and it dropped during summer, which would be mostly because of high arsenic concentration in ashes of log burners. This study shows ashes of burning timbers can impact arsenic contamination mostly because of using Copper-Chrome-Arsenic wood preservatives (CCA). Also, the lab results show the arsenic level even in ashes of untreated timber is around 96 ppm. The ashes of H3, H4, and H5 treated timbers contain approximately 133,000, 155,000, and 179,000 ppm of arsenic, which one kg of them can increase arsenic concentration around 10 ppm in 13.3, 15.5 and 17.9 tons of dry compost products. The main problem is many people look at ashes and treated timber as organic materials; however, ashes of treated and untreated timbers contained high concentrations of arsenic. Therefore, it was necessary to warn people about the dangers of putting any ashes in organic waste bins.