Soil salinity is a global threat to the environmental sustainability, in particular to the developing countries due to their limited resources for soil reclamation. In a greenhouse pot experiment, Pennisetum giganteum, was investigated for its tolerance to salt stress and simultaneous phytoremediation capability. 4 weeks post-germination, NaCl (10, 50, 150, 250, 350, 450 and 550 mM) and tap water (control) was applied after every 2 consecutive days for two weeks in a completely randomized design and their effects were established in the growth and physico-chemical aspects of these plants. Our results indicated that P. giganteum withstood high salt stress (with 550 mM NaCl tolerance threshold level). Interestingly, the plants grown under saline conditions had higher biomass yield when compared to the control. Furthermore, the antioxidant activity and proline content of plants under saline conditions were significantly (p < 0.05) higher than those of control plants, indicating their adaptability to high salt stress. Biochemical analysis such as chlorophyll contents, total soluble sugar, total phenol and protein contents revealed considerable differences between plants grown under higher NaCl stress compared to the control conditions. Additionally, significantly different ionic flux along with high K⁺/Na⁺ ratio was observed in plants grown under a range of saline conditions. The results obtained are therefore of value to indicate P. giganteum an eco-friendly alternate source for the phytoremediation of saline soils and may be used as base for future research on this plant. Effective strategies need to be adopted with this plant to reclaim saline-degraded as well as marginal soils.

Functional state of intestinal barrier plays an important role for environmental animals in being against various toxicants. We investigated GATA transcriptional factor ELT-2-mediated intestinal response to nanopolystyrere in Caenorhabditis elegans. Prolonged exposure to nanopolystyrene (≥1 μg/L) induced an increase in expression of ELT-2, and intestinal RNA interference (RNAi) knockdown of elt-2 caused enhancement in intestinal permeability. Meanwhile, mutation of elt-2 resulted in susceptibility to nanopolystyrene toxicity, and ELT-2 functioned in intestine to regulate the nanopolystyrene toxicity. ERM-1, CLEC-63, and CLEC-85 were identified as targets of ELT-2 in regulating the nanopolystyrene toxicity. ERM-1 was required for maintaining functional state in intestinal barrier, and functioned synergistically with CLEC-63 or CLEC-85 to regulate nanopolystyrene toxicity. Therefore, activation of intestinal ELT-2 by nanopolystyrere could mediate a protective strategy to maintain the functional state of intestinal barrier. During this process, intestinal ELT-2 activated two different molecular signals (ERM-1 signal and CLEC-63/85 signal) for nematodes against the nanopolystyrene toxicity.

Microplastic pollution is a major global environmental problem in both aquatic and terrestrial environments. Pesticides are frequently applied to agricultural soil to reduce the effects of pests on crops, but may also affect the degradation of plastics. In this study, we generated microplastics from polyethylene (PE) film and biodegradable poly(butylene adipate-co-terephthalate) (PBAT) film and determined (1) the effect of prothioconazole on degradation of the microplastics, and (2) the adsorption and release characteristics of heavy metals (Cr, Cu, As, Pb, Ba, and Sn) by the microplastics during degradation process. Changes of surface functional groups and morphologies were measured by FTIR and SEM, while metal concentrations were determined by ICPMS. Prothioconazole was found to promote plastic degradation. PBAT degraded faster and adsorbed more heavy metals from the soil than PE. Whether the microplastics adsorb or release heavy metals depended on the metal and their concentrations. Prothioconazole inhibited the adsorption of Cr, As, Pb and Ba by microplastics, promoted the adsorption of Cu, and had no significant effect for Sn. These results can help to assess the ecological risk of microplastic pollution from plastic mulch when combined with heavy metals.

Current studies indicate that long-term exposure to ambient fine particulate matter (PM₂.₅) is related with global mortality, yet no studies have explored relationships of PM₂.₅ and its species with DNAm PhenoAge acceleration (DNAmPhenoAccel), a new epigenetic biomarker of phenotypic age. We identified which PM₂.₅ species had association with DNAmPhenoAccel in a one-year exposure window in a longitudinal cohort. We collected whole blood samples from 683 elderly men in the Normative Aging Study between 1999 and 2013 (n = 1254 visits). DNAm PhenoAge was calculated using 513 CpGs retrieved from the Illumina Infinium HumanMethylation450 BeadChip. Daily concentrations of PM₂.₅ species were measured at a fixed air-quality monitoring site and one-year moving averages were computed. Linear mixed-effect (LME) regression and Bayesian kernel machine (BKM) regression were used to estimate the associations. The covariates included chronological age, body mass index (BMI), cigarette pack years, smoking status, estimated cell types, batch effects etc. Benjamini-Hochberg false discovery rate at a 5% false positive threshold was used to adjust for multiple comparison. During the study period, the mean DNAm PhenoAge and chronological age in our subjects were 68 and 73 years old, respectively. Using LME model, only lead and calcium were significantly associated with DNAmPhenoAccel. For example, an interquartile range (IQR, 0.0011 μg/m³) increase in lead was associated with a 1.29-year [95% confidence interval (CI): 0.47, 2.11] increase in DNAmPhenoAccel. Using BKM model, we selected PM₂.₅, lead, and silicon to be predictors for DNAmPhenoAccel. A subsequent LME model showed that only lead had significant effect on DNAmPhenoAccel: 1.45-year (95% CI: 0.46, 2.46) increase in DNAmPhenoAccel following an IQR increase in one-year lead. This is the first study that investigates long-term effects of PM₂.₅ components on DNAmPhenoAccel. The results demonstrate that lead and calcium contained in PM₂.₅ was robustly associated with DNAmPhenoAccel.

The long-term contamination of soil by microplastics may pose risks that are often still not well understood, and the ecological effects of microplastics are mainly dependent on their environmental behavior in environments. This study used saturated quartz sand as a solid porous medium to study the migration and influencing factors of 40–48 μm polyethylene (PE) particles in saturated porous media. The breakthrough curves at different injection concentrations (0.3, 0.4, 0.5 mg/L), flow rates (1.0, 1.5, 2.0, 2.5 ml/L), porous medium particle sizes (1–2, 2–4 mm), ionic strengths (0, 0.01, 0.05 mol/L) and concentrations of fulvic acid (FA) (0, 5, 10 mg/L) were compared and analyzed. The Derjaguin-Landau-Verwey-Overbeek (DLVO) theory was used to more accurately explain relevant transport behaviors. The results showed that the input concentration, flow rate, and particle size can affect the migration of PE particles individually or in combination. As ionic strength increased, the repulsion between microplastics and quartz sand gradually disappeared according to DLVO theory, and their attraction gradually strengthened. As a result, fewer microplastics could penetrate the sand column and reach the water body. With the continuous addition of FA, the repulsive energy between microplastics and quartz sand rose from DLVO theory, and the migration ability of microplastics initially increased before becoming stable because of the effect of straining. In all cases, the migration ability of PE was low (C/C₀ < 0.35), and most PE particles remained in the porous media during the whole experimental periods. This study provides new insights of understanding the migration of microplastics in environment.

White cabbage, Brassica oleracea, plants and artificial leaves covered with B. oleracea epicuticular wax were exposed to α-pinene and α-pinene oxidation products formed through the oxidation of α-pinene by ozone (O₃) and hydroxyl (OH) radicals. O₃ and OH-induced oxidation of α-pinene led to the formation of oxygenated volatile organic compounds (OVOCs) and secondary organic aerosol particles (SOA), referred to together as oxidation products (OP). Exposure of cabbage plants to O₃ and OH-induced α-pinene OP led to the deposition and re-emission of gas-phase OP by exposed cabbage plants. In a series of 2-choice bioassays, the specialist cruciferous herbivore, Plutella xylostella adults deposited less eggs on artificial leaves exposed to α-pinene OP than on control plants exposed to clean filtered air. P. xylostella larvae did not show a specific feeding preference when offered leaves from different exposure treatments. However, the generalist Indian stick insect, Carausius morosus, fed more on control filtered air-exposed plants than on those exposed to α-pinene OP. Taken together, our results show that exposure to α-pinene oxidation products affects VOC emissions of B. oleracea and alters P. xylostella oviposition and C. morosus feeding responses.

Acidification in variable charge soils is on the rise due to increased acid deposition and use of nitrogenous fertilizers. The associated low pH and cation exchange capacity make the soils prone to depleted base cations and increased levels of Al³⁺. Consequently, Al toxicity to plants and soil infertility decrease crop yield. This study was designed to investigate the effect of Pseudomonas fluorescens on the acidification of two Ultisols. The simulated acidification experiment demonstrated that the pH of bacteria-treated soil was higher than that of control under similar conditions, suggesting that the adhered bacteria inhibited soil acidification. This observation was attributed to the association of organic anions (RCOO⁻ or RO⁻) on bacteria with H⁺ to form neutral molecules (RCOOH or ROH) and reducing the activity of H⁺ in solution. The bacteria also inhibited the increase in soil soluble Al and exchangeable Al during soil acidification. The adhesion of bacteria on the soils increased soil effective cation exchange capacity (ECEC) and exchangeable base cations at each pH compared to control. The release of exchangeable base cations from bacteria-treated soil, and the decrease in soil ECEC and exchangeable base cations with decreasing pH confirmed that protonation of organic anions on adhered bacteria was mainly responsible for the inhibition of soil acidification. The change of zeta potential of the bacteria with pH and the ART-FTIR analysis at various pH provided more evidence for this mechanism. Therefore, the bacteria in variable charge soils played an important role in retarding soil acidification.

Surface waters could be a dominant route by which antibiotic resistance genes (ARGs) are disseminated. In the present study we explored the prevalence and abundance of ARGs [blaCTX₋M₋₁, erm(B), sul1, tet(B), tet(M), and tet(X)], class 1 integron-integrase gene (intI1), and IncP-1 and IncQ-1 plasmids in eight irrigation return flows (IRFs) and a background site (Main Line Canal, MLC) in the Upper Snake Rock watershed in southern Idaho. Grab samples were collected on a monthly basis for a calendar year, which were processed to extract microbial DNA, followed by droplet digital PCR to quantify the gene copies on an absolute (per 100 mL) and relative (per 16S rRNA gene copies) basis. The antibiotic resistance and intI1 genes and IncP-1/IncQ-1 plasmids were recovered at all IRF sampling sites with detections ranging from 55 to 81 out of 81 water sampling events. The blaCTX₋M₋₁ gene was detected the least frequently (68%), while the other genes were detected more frequently (88–100%). All of the genes were also detected at MLC from April to Oct when water was present in the canal. The genes from lowest to greatest relative abundance in the IRFs were: blaCTX₋M₋₁ < erm(B) < tet(B) < IncQ-1 < tet(M) < sul1 < intI1 = IncP-1 < tet(X). When compared to the average annual relative gene abundances in MLC water samples, they were found to be at statistically greater levels (P ≤ 0.008) except that of the IncP-1 and IncQ-1 plasmids (P = 0.8 and 0.08, respectively). The fact that most IRFs contained higher levels than found in the canal water, indicates that IRFs can be a point source of ARGs that ultimately discharge into surface waters.

Exposure to environmental metals has been reported to be associated with airway inflammation. Fractional exhaled nitric oxide (FeNO) is an important inflammatory biomarker of the airway. However, the associations between metal exposures and FeNO change and the underlying mechanisms remain unclear. To investigate the associations between urinary metals and FeNO, and the potential role of Club cell secretory protein (CC16), a lung epithelial biomarker, in these associations. We conducted a cross-sectional study from the Wuhan-Zhuhai cohort and measured eight urinary metals, plasma CC16 and FeNO among 3067 subjects by using inductively coupled plasma-mass spectrometry, enzyme-linked immunosorbent assay kit and Nano Coulomb Nitric Oxide Analyzer, respectively. Mixed linear models were used to quantify dose-relationships between urinary metals and FeNO, as well as urinary metals and plasma CC16. The potential role of plasma CC16 in the associations between urinary metals and FeNO was estimated using mediationanalyses. After adjusting for covariates, one percent increase in urinary vanadium, nickel or antimony was associated with a respective 6.60% (95% CI: 3.52%, 9.68%), 2.18% (0.45%, 3.91%), 4.87% (1.47%, 8.27%) increase in FeNO level. The adverse associations were much stronger among participants with low concentration of plasma CC16 than those with high CC16 level. Moreover, plasma CC16 decreased monotonically with increasing quartiles of urinary vanadium, nickel or antimony. Mediation analyses found that CC16 mediated the associations between urinary metals and FeNO by 5.64%, 39.06% and 25.18% for vanadium, nickel and antimony respectively. CC16 plays an important role in airway inflammation. General population with lower plasma CC16 concentration is more likely to suffer from airway inflammation when exposed to high levels of vanadium, nickel or antimony.

A widespread monitoring network of Airbox microsensors was implemented since 2016 to provide high-resolution spatial distributions of ground-level PM₂.₅ data in Taiwan. We developed models for estimating ground-level PM₂.₅ concentrations for all the 3 km × 3 km grids in Taiwan by combining the data from air quality monitoring stations and the Airbox sensors. The PM₂.₅ data from the Airbox sensors (AB-PM₂.₅) was used to predict daily mean PM₂.₅ levels at the grids in 2017 using a semiparametric additive model. The estimated PM₂.₅ level at the grids was further applied as a predictor variable in the models to predict the monthly mean concentration of PM₂.₅ at all the grids in the previous year. The modeling–predicting procedures were repeated backward for the years from 2016 to 2006. The model results revealed that the model R² increased from 0.40 to 0.87 when the AB-PM₂.₅ data were included as a nonlinear component in the model, indicating that AB-PM₂.₅ is a significant predictor of ground-level PM₂.₅ concentration. The cross-validation (CV) results demonstrated that the root of mean squared prediction errors of the estimated monthly mean PM₂.₅ concentrations were smaller than 5 μg/m³ and the R² of the CV models of 0.79–0.88 during 2006–2017. We concluded that Airbox sensors can be used with monitoring data to more accurately estimate long-term exposure to PM₂.₅ for cohorts of small areas in health impact assessment studies.