Historical increases in emissions and atmospheric deposition of oxidized and reduced nitrogen (N) provided the impetus for extensive, global-scale research investigating the effects of excess N in terrestrial and aquatic ecosystems, with several regions within the Eastern Deciduous Forest of the United States found to be susceptible to negative effects of excess N. The Clean Air Act and associated rules have led to decreases in emissions and deposition of oxidized N, especially in eastern U.S., representing a research challenge and opportunity for ecosystem ecologists and biogeochemists. The purpose of this paper is to predict changes in the structure and function of North American forest ecosystems in a future of decreased N deposition. Hysteresis is a property of a system wherein output is not a strict function of corresponding input, incorporating lag, delay, or history dependence, particularly when the response to decreasing input is different from the response to increasing input. We suggest a conceptual hysteretic model predicting varying lag times in recovery of soil acidification, plant biodiversity, soil microbial communities, forest carbon (C) and N cycling, and surface water chemistry toward pre-N impact conditions. Nearly all of these can potentially respond strongly to reductions in N deposition. Most responses are expected to show some degree of hysteresis, with the greatest delays in response occurring in processes most tightly linked to “slow pools” of N in wood and soil organic matter. Because experimental studies of declines in N loads in forests of North America are lacking and because of the expected hysteresis, it is difficult to generalize from experimental results to patterns expected from declining N deposition. These will likely be long-term phenomena, difficult to distinguish from other, concurrent environmental changes, including elevated atmospheric CO₂, climate change, reductions in acidity, invasions of new species, and long-term vegetation responses to past disturbance.

We measured the concentrations of organophosphate esters (OPEs) in some biotic samples which can serve as human foodstuffs and ambient environments including air and river water from an agricultural area of Chongqing, western China. Fish samples exhibited highest OPEs levels (960 ng/g lipid weight) among the biota, followed by chicken (676 ng/g lw), cattle (545 ng/g lw) and pigs (535 ng/g lw). Tributyl phosphate (TNBP), tris (2-methylpropyl) (TIBP) and chlorinated OPEs were the major analogs in biotic samples, which appeared similar with the patterns from river water and outdoor air, but apparently different from indoor air. To further investigate the influence of ambient environment on the distribution of OPEs in biota, we analyzed the correlation between OPEs concentrations in ambient environment and biological samples, and the results revealed that most of the samples (except for pig samples) heavily correlated with outdoor air, whereas only fish and cattle samples were strongly correlated with river water. The partitioning behaviors of OPEs among biota, air and river water were also studied through calculating the biota-water accumulation factors (BWAFs), biota-air accumulation factors (BAAFs) and air-water partitioning factor (AWPFs). Significantly linear correlations (P < 0.05) were observed between log (BWAFs) and log (KOW) values, and between log (AWPFs) and log H (Henry's law constants), nevertheless log (BAAFs) was increasing along with the log (KOA) values. The daily intake (DI) values were estimated via foodstuffs ingestion and environmental exposure. The estimated DI values of OPEs from food and ambient environments were 1.78 ng/kg-bw/day, 1.23 ng/kg-bw/day and 1.42 ng/kg-bw/day in toddlers, children and adults, respectively, which lay at the low end of the reported data and well below the reference dose (RfD).

Ambient fine particulate matter (PM2.5) as an environmental pollution has been associated with the lung cancer. However, the mechanism of epigenetics such as miRNAs deregulation between PM2.5-exposure and lung cancer has not been elucidated clearly. Twenty C57BL/6 mice were divided randomly into 2 groups and exposed to the filtered air (FA) and the concentrated air (CA), respectively. The FA mice were exposed to filtered air in chambers with a high-efficient particulate air filter (HEPA-filter), and the CA mice were exposed to concentration ambient PM2.5. The total duration of exposure was performed 6 h per day from December 1st, 2017 to January 27th, 2018. The mice exposed 900.21 μg/m³ PM2.5 for 6 h per day in CA chamber, which was nearly equaled to 225.05 μg/m³ for 24-h calculatingly. After exposure, the serum miRNAs levels were detected by microarray. Genetic and pathological alterations in lung of mice with/without PM2.5 exposure were detected. 38 differential miRNAs in serum of mice were found after PM2.5 exposure for 8 weeks. Among of them, 13 miRNAs related with lung cancer were consistent in serum and lung of mice. The target genes of 13 deregulated miRNAs including CRK, NR2F2, VIM, RASSF1, CCND2, PRKCA, SIRT1, CDK6, MAP3K7, HIF1A, UBE2V2, ATG10, BAX, E2F1, RASSF5 and CTNNB1, could involve in the pathway of lung cancer developing. Compared with the FA group, the significantly increases of histopathological changes, ROS and DNA damage were observed in lung of mice in CA group. Our study suggested that miRNAs in serum could be identified as candidate biomarkers to predict the lung cancer development during early PM2.5 exposure.

Immobilization of enzymes on carriers have been pursued to make the enzyme stable, reusable and obtaining even better enzyme activity. Due to the highly stable two-dimensional layer structure, large surface area and pore volume, graphene materials were seemed as ideal carrier for enzyme immobilization. In this paper, pristine few layer graphene (FLG) was applied to interact with laccase to synthesize laccase-graphene composite and the results of AFM, FT-IR and adsorption isotherm suggested that laccase was loaded on the FLG with a very high loading dosage (221.1 mg g⁻¹). Based on the measured interaction force and binding type between laccase and graphene, we proposed that the great enzyme loading on FLG is likely due to the non-covalent π-π stacking in addition to the large surface area of FLG. The composite has better stability to the variance of pH and storage temperature than free laccase. The synthesized composite can effectively transform beta-blocker labetalol with an enhanced efficiency, though the possible reaction pathways kept not changing. We further performed molecular simulation study on the crystal structure variation of laccase binding on FLG and proposed that catalytic activity enhancement may be attributed to the more exposure extent of the catalytic center of laccase. In addition, the laccase-graphene composite can be reused more than ten times in catalyzing the labetalol removal.

The cell-free dithiothreitol (DTT) assay is widely used and the DTT consumption rate is interpreted to assess the oxidative potential (OP). Most researchers use an experimental procedure developed by Cho et al. (2005) while some adopt a procedure by Li et al. (2009). The key difference between the two procedures is the initial DTT concentration, 100 μM used in the former and 20 μM in the latter, raising an unaddressed issue of comparability. We examine in this work this issue using metal-free humic-like substance (HULIS) samples isolated from ambient aerosol and two metals (i.e. copper and manganese). We found that higher initial DTT concentrations led to higher DTT consumption rates for both HULIS and metals. For HULIS, the increase in DTT consumption rate was proportional to the initial DTT concentration (i.e., roughly by 5-fold), allowing correction of the concentration effect and direct comparison of results from the two protocols. However, the proportionality did not hold for the metals or metal-organic mixtures. The increase was much lower than the proportionality of 5 and metal concentration-dependent, specifically, 1.2–1.3 for Cu and from negligible to 2.0 for Mn. For six water extracts of ambient aerosol samples, in which HULIS and metals co-exist, the proportionality ranged from 1.3 to 2.2. This deviation from a linear dependence on initial DTT concentration, plausibly due to metal-DTT binding, impedes assessing and comparing OP of metals and metal-organic mixtures using different implementations of the DTT assay. Considering the different antioxidants concentrations in real human lung fluid, this work raises caution about using the DTT assay to assess metal-containing mixtures, such as ambient aerosol samples.

Triphenyl phosphate (TPHP; CAS # 115-86-6), a commonly used plasticizer and flame retardant, has been reported in wild birds and identified as a potential high-risk chemical. We exposed Japanese quail (Coturnix japonica) by in ovo injection, and once hatched, orally each day for 5 days to safflower oil (controls) or TPHP dissolved in vehicle at low (5 ng TPHP/g), mid (50 ng TPHP/g), or high (100 ng TPHP/g) nominal TPHP doses. The low TPHP dose reflected concentrations in wild bird eggs, with mid and high doses 10x and 20x greater to reflect potential increases in environmental TPHP concentrations in the future. Despite no effects on mRNA expression in thyroid-related genes, TPHP exposure enhanced thyroid gland structure in high TPHP males, but in females, suppressed thyroid gland structure and activity (all TPHP females), and circulating free triiodothyronine (high TPHP females only). Consistent with thyroidal changes, and compared to controls, mid and high TPHP chicks experienced significantly reduced resting metabolic rate (≤13%) and growth (≤53%); mid TPHP males and high TPHP females were significantly smaller. The observed thyroidal effects and suppressed growth and metabolic rate of the quail chicks suggest that TPHP may adversely affect the health of wild birds.

Roadside food-vending shanties using coal cookstoves may be an important source of carbon monoxide (CO) exposure in megacities in India. The shanties are often small, congested and poorly ventilated, and very little is known about the level of human exposure to CO. Here, we assessed the level of exposure to CO in 25 roadside food-vending shanties using coal cookstoves in Kolkata, India. Portable electrochemical CO monitors were used to measure CO concentrations during peak and non-peak customer-periods in closed (blocked from three sides) and semi-closed (blocked from two sides) shanties. Measurements were taken where customers sit indoor about 5–7 ft away from the cookstoves. The shanties' ventilation rates were measured using tracer gas concentration-decay technique. Levels of blood carboxyhaemoglobin (COHb) and exhaled CO were estimated using regression models. The 1-hr time weighted average (TWA) indoor CO exposure levels ranged from 7.8 to 18.1 ppm during peak-periods, and 0.7–3.1 ppm during non-peak-periods. The exposure levels during peak-periods exceeded the USEPA's reference limit of 9 ppm in all cases in the closed shanties, and in 71% of cases in the semi-closed shanties. The ventilation rates ranged from 5.5 to 23.4 and 14.8 to 32.5 cubic feet per minute (cfm) per person for the closed and semi-closed shanties, respectively, indicating poor ventilation in some shanties. There was significant variation (p = 0.01) in the level of indoor CO exposure between peak and non-peak periods, and between shanty types. The estimated levels of blood COHb during peak and non-peak hours were 0.78 ± 0.7% and 0.35 ± 0.07%, respectively, that were within the normal physiological values in non-smokers.

The photocatalytic inactivation of Escherichia coli (E. coli) under light-emitting diode (LED) light irradiation was performed with P/Ag/Ag₂O/Ag₃PO₄/TiO₂ photocatalyst to investigate the photocatalytic bactericidal activity. Our work showed that this composite photocatalyst possessed remarkable bacterial disinfection ability and could completely inactivate 10⁸ cfu/mL of E. coli within just 40 min under the optimum catalyst loading of 0.5 g/L. The effects of different environmental factors, including light wavelength, light intensity, temperature, solution pH and inorganic ions, on the inactivation efficiency were evaluated. The results showed that bacteria inactivation by P/Ag/Ag₂O/Ag₃PO₄/TiO₂ was more favorable with blue colored LED irradiation, light intensity at 750 W/m², temperature in the range of 30–37 °C and pH values at natural or slightly alkaline condition. The existence of different inorganic ions under normal environmental level had no significant impact on the bactericidal performance. In addition, during the inactivation process, the morphology changes of E. coli cells were directly observed by scanning electron microscope (SEM) and further proved by the measurement of K⁺ leakage from the inactivated E. coli. The results demonstrated that the photocatalytic inactivation caused drastic damage on bacterial cells membrane. Furthermore, the mechanisms of photocatalytic bacterial inactivation were also systemically studied and the results confirmed that the excellent disinfection activity of P/Ag/Ag₂O/Ag₃PO₄/TiO₂ resulted from the major reactive species: h⁺ and ·O₂⁻ from photocatalytic process instead of the leakage of Ag⁺ (≤0.085 ± 0.005 mg/L) from photocatalyst. These results indicate that P/Ag/Ag₂O/Ag₃PO₄/TiO₂ photocatalyst has promising potential for real water sterilization application.

The toxic potentially toxic metals elements (PTEs) discharged from industrial activities and agricultural practices persistently pose multiple hazards to environment and living organisms. Microbe-assisted phytoremediation provide an effective approach to remediate PTEs-contaminated soils. A phytoextraction process involved the application of Streptomyces pactum (Act12, 1.0, 2.0 and 3.0 g kg⁻¹ dry soil, respectively) alone/jointly with sulfur was executed. The main texture of the tested soil was sandy loam and with a pH 8.27. The obtained results showed that the leaf pigments and plant biomass were improved after the application of the Act12, while the shoot fresh weight, chlorophyll a and chlorophyll b decreased by 57.8, 38.2 and 40.7%, respectively, after treatment with sulfur. Similarly, sulfur application facilitated the malondialdehyde (MDA) production by 18.4–33.6% compared to the control (no amendments). Both peroxidase (POD) and superoxide dismutase (SOD) activities were boosted, while the catalase (CAT) activity was suppressed with Act12 alone/jointly with sulfur treatment. The sulfur combined with elevated Act12 levels notably increased the cadmium (Cd) and zinc (Zn) concentrations both in shoots and roots, while the elemental extraction amount showed the removal efficiency following the order: Act12 alone ＞ control ＞ Act12 jointly with sulfur. Taken together, the results suggested that Streptomyces pactum and sulfur assisted the phytoremediation process, while further studies should be conducted in the field to test practical application.

Glufosinate-ammonium (GLA) is a spectrum herbicide that is widely used in agriculture. The toxic effects of GLA on plants and mammals have been extensively studied; however, little is known about its effects on reptiles. In this study, male lizards (Eremias argus) were exposed to GLA contaminated soil for 60 days. Physical conditions, organ coefficients, antioxidant enzyme activity, tissue distribution, histopathological damage, steroid hormones levels, and related gene expression of sex steroids were evaluated. In contrast to unexposed control lizards, the body mass index of the GLA group was decreased, which elucidated that GLA adversely affected the physical condition of E. argus. Changes in antioxidant enzyme activities in response to elevated malondialdehyde levels in lizard testis indicated that testes were strongly affected by oxidative damage, and the increased testis index was associated with severe testis lesions. Moreover, alterations of plasma sex hormone levels and related gene expression levels of sex steroids were also observed, and the mechanism underlying the induction of reproductive toxicity was clarified. The activity of glutamine synthetase was severely inhibited in the liver of the GLA exposure group. Based on the results of liver index and histopathology examinations, the hepatotoxicity effect of GLA was confirmed.