Nighttime lighting is an increasingly important anthropogenic environmental stress on plants and animals. Exposure to unnatural lighting environments may disrupt the circadian rhythm of organisms. However, the sample size of relevant studies, e.g. disruption of the molecular circadian clock by light pollution, was small (<10), which led to low statistical power and difficulties in replicating prior results. Here, we developed a power-calibrated statistical approach to overcome these weaknesses. The results showed that the effect size of 2.48 in clock genes expression induced by artificial light would ensure the reproducibility of the results as high as 80%. Long-wavelength light (560–660 nm) entrained expressions of the positive core clock genes (e.g. cClock) and negative core clock genes (e.g. cCry1, cPer2) in robust circadian rhythmicity, whereas those clock genes were arrhythmic in short-wavelength light (380–480 nm). Further, we found artificial light could entrain the transcriptional-translational feedback loop of the molecular clock in a wavelength-dependent manner. The expression of the positive core clock genes (cBmal1, cBmal2 and cClock), cAanat gene and melatonin were the highest in short-wavelength light and lowest in long-wavelength light. For the negative regulators of the molecular clock (cCry1, cCry2, cPer2 and cPer3), the expression of which was the highest in long-wavelength light and lowest in short-wavelength light. Our statistical approach opens new opportunities to understand and strengthen conclusions, comparing with the studies with small sample sizes. We also provide comprehensive insight into the effect of wavelength-specific artificial light on the circadian rhythm of the molecular clock in avian species. Especially, the global lighting is shifting from “yellow” sodium lamps, which is more like the long-wavelength light, toward short-wavelength light (blue light)-enriched “white” light-emitting diodes (LEDs).

MicroRNAs (miRNAs) are a class of small, non-coding RNAs with a post-transcriptional regulatory function on gene expression and cell processes, including proliferation, apoptosis and differentiation. In recent decades, miRNAs have attracted increasing interest to explore the role of epigenetics in response to air pollution. Air pollution, which always contains kinds of particulate matters, are able to reach respiratory tract and blood circulation and then causing epigenetics changes. In addition, extensive studies have illustrated that miRNAs serve as a bridge between particulate matter exposure and health-related effects, like inflammatory cytokines, blood pressure, vascular condition and lung function. The purpose of this review is to summarize the present knowledge about the expression of miRNAs in response to particulate matter exposure. Epidemiological and experimental studies were reviewed in two parts according to the size and source of particles. In this review, we also discussed various functions of the altered miRNAs and predicted potential biological mechanism participated in particulate matter-induced health effects. More rigorous studies are worth conducting to understand contribution of particulate matter on miRNAs alteration and the etiology between environmental exposure and disease development.

The microbe-driven iron cycle plays an important role in speciation transformation and migration of arsenic (As) in soil-rice systems. In this study, pot experiments were used to investigate the effect of bacterial iron (Fe) reduction processes in soils on As speciation and migration, as well as on As uptake in soil-rice system. During the rice growth period, pH and electrical conductivity (EC) in soil solutions initially increased and then decreased, with the ranges of 7.4–8.8 and 116.3–820 mS cm⁻¹, respectively. The concentrations of Fe, total As and As(III) showed an increasing trend in the rhizosphere and non-rhizosphere soil solutions with the increasing time. Fe concentrations were significantly positively correlated with total As and As(III) concentrations (***p < 0.001) in the soil solutions. The abundances of the arsenate reductase gene (arsC) and the As(III) S-adenosylmethionine methyltransferase gene (arsM) in rhizosphere soils were higher than those in non-rhizosphere soils, while the abundance of the Fe-reducing bacteria (Geo) showed an opposite trend. Moreover, it showed that the Geo abundance was significantly positively correlated with that of the arsC (***p < 0.001) and arsM (**p < 0.01) genes, respectively. The abundances of Geo, arsC and arsM genes were significantly positively correlated with the concentrations of Fe, total As and As(III) in the soil solutions (*p < 0.05). Moreover, the abundances of arsC and arsM genes were significantly negatively correlated with total As and As(III) in rice grains (*P < 0.05). These results showed that the interaction of bacterial Fe reduction process and radial oxygen loss from roots promoted the reduction and methylation of As, and then decreased As uptake by rice, which provided a theoretical basis for alleviating As pollution in paddy soils.

Modification of nighttime light levels by artificial illumination (artificial light at night; ALAN) is a rapidly increasing form of human disturbance that affects natural environments worldwide. Light in natural environments influences a variety of physiological and ecological processes directly and indirectly and, as a result, the effects of light pollution on species, communities and ecosystems are emerging as significant. Small prey species may be particularly susceptible to ALAN as it makes them more conspicuous and thus more vulnerable to predation by visually oriented predators. Understanding the effects of disturbance like ALAN is especially important for threatened or endangered species as impacts have the potential to impede recovery, but due to low population numbers inherent to at-risk species, disturbance is rarely studied. The endangered Stephens’ kangaroo rat (SKR), Dipodomys stephensi, is a nocturnal rodent threatened by habitat destruction from urban expansion. The degree to which ALAN impacts their recovery is unknown. In this study, we examined the effects of ALAN on SKR foraging decisions across a gradient of light intensity for two types of ALAN, flood and bug lights (756 vs 300 lumen, respectfully) during full and new moon conditions. We found that ALAN decreased probability of resource patch depletion compared to controls. Moreover, lunar illumination, distance from the light source and light type interacted to alter SKR foraging. Under the new moon, SKR were consistently more likely to deplete patches under control conditions, but there was an increasing probability of patch depletion with distance from the source of artificial light. The full moon dampened SKR foraging activity and the effect of artificial lights. Our study underscores that ALAN reduces habitat suitability, and raises the possibility that ALAN may impede the recovery of at-risk nocturnal rodents.

Present study reports the laboratory and field scale application of different organic and inorganic amendments to immobilize cadmium (Cd) and lead (Pb) in a co-contaminated alluvial paddy soil. For that purpose, lime, biochar, Fe-biochar and two composite amendments (CA) composed of biochar, lime, sepiolite and zeolite (CA1: composite amendment 1) and manure, lime and sepiolite (CA2: composite amendment 2) were firstly tested in an incubation experiment to ameliorate Cd and Pb co-contaminated alluvial soil. It was observed that liming and CA2 elevated the soil pH and reduced DTPA extractable Cd and Pb in the incubated soil leading to higher metal immobilization. Therefore, efficiency of lime and CA2 was further investigated in field conditions with mid rice as the test crop to evaluate field scale immobilization and precise application rate for the tested soil type. DTPA and CaCl₂ extractable Cd (46 and 51%) and Pb (68 and 70%) in field soil were decreased with applied treatments. Speciation of Cd and Pb also promoted conversion of metal exchangeable contents to less-available forms. Activated functional groups on amendments’ surface (_OH bonding, C_O and CO, -O-H, Si–O–Si, carboxylic and ester groups) sequestered metals by precipitation, adsorption, ion exchange or electro static attributes. Application of lime at 2400 kg/acre (T4) and CA2 at 1200 kg/acre was more effective in reducing rice shoot and grains metal contents. Moreover, obtained results in terms of pH, extractable content, speciation and yield, and microanalysis of amendments highlights the remarkable efficiency of lime and composite amendment to sorb Cd and Pb providing the key evidence of these amendments for metals immobilization and environmental remediation. Considering these results, lime and CA2 are potential amendments for co-contaminated rice field especially in context of alluvial soil.

The pollution of wastewater with antibiotics and antibiotics resistance genes has attracted public concerns about ecosystem and global health. Swine wastewater can contain high concentrations of antibiotics, especially sulfonamides, even after full-scale wastewater treatment. In this study, mesocosm-scale vertical flow constructed wetlands (VF-CWs) were applied to abate nutrients and antibiotics in swine wastewater containing sulfonamides. VF-CWs performed well in the removal of both nutrients and antibiotics. Sulfonamides did not influence total organic carbon (TOC) and total phosphorus (TP) removal, and even slightly enhanced NH₄⁺–N removal. High removal efficiencies (26.42–84.05%) were achieved for sulfadiazine (SDZ), sulfamethoxazole (SMX) and sulfamethazine (SMZ). Together with lab-scale sorption and biodegradation experiments, microbial degradation was found to be the most important removal mechanism for sulfonamides in VF-CWs. Sulfonamides addition increased bacterial alpha-diversity and changed microbial community structure. Moreover, antibiotics promoted antibiotic-resistant or -degrading bacteria. Bacillus, Geobacter and other seven genera were correlated with sulfonamides reduction under either aerobic or anaerobic condition. In summary, VF-CW is a suitable alternative for swine wastewater treatment, and biodegradation plays the key role in sulfonamides abatement.Main findings of the work.This was the first work to combine bacterial community analysis with microcosm experiments to uncover the major removal mechanism of sulfonamides in constructed wetlands.

Radon is a natural radioactive gas present in the environment, which is considered as the second most important lung cancer cause worldwide. Currently, radon gas is under focus and was classified as contaminant of emerging concern, which is responsible for serious biological/health effects in human. In presented work we propose the numerical model and analysis method for radon diffusion rate measurements and radon transport parameters determination. The experimental setup for radon diffusion was built in a classical, two chamber configuration, in which the radon source and outlet reservoirs are separated by the sample being tested. The main difference with previously known systems is utilization of only one radon detector, what was achieved by a careful characterization of the Rn-222 source and development of a numerical model, which allows for exact determination of radon transport parameters by fitting simulated radon concentration profile in the outlet reservoir to experimental data. For verification of the developed system, several insulation materials commonly used in building industry and civil engineering, as well as, common building materials (gypsum, hardened cement paste, concrete) were tested for radon diffusion rate through these barriers. The results of radon transmittance, permeability and diffusion coefficients for investigated materials are in compliance with values known previously from the literature. The analysis method is fast and efficient, and requires measurement period varying from a dozen or so hours up to 2–3 days depending on material properties. The described method is entirely based on a numerical analysis of the proposed differential equation model using freely available SCILAB software and experimental data obtained during sample measurements.

Membrane concentrated landfill leachate (MCLL) contains large amounts of recalcitrant organic matter that cause potential hazards to the environment. Knowledge on the compositional variation of MCLL during treatment is important for a better understanding on the degradation pathway of organic pollutants. In this work, the structural change of MCLL during Fenton oxidation process was examined using spectroscopic techniques. The removal rates of COD, TOC and UV254 reached 78.9 ± 1.3%, 70.2 ± 1.4% and 90.64 ± 1.6%, respectively, under the optimal condition (i.e., dosage of H2O2 = 9.0 mL/200 mL, H2O2/Fe(II) molar ratio = 3.0, pH = 3.0, time = 40 min). Spectral analyses suggested that aromatic/CC structure and CO bonds in MCLL can be successfully destroyed by Fenton oxidation, resulting in a decrease in molecular weight. One fulvic-like and one humic-like components were identified in MCLL, both of which can be removed by Fenton treatment. In addition, two-dimensional correlation spectroscopic analyses suggested the oxidative changes of MCLL structure in the order of fulvic-like component/unsaturated conjugated bond > aromatic structure > humic-like component. The results may provide a new insight to the understanding on the structure variation of MCLL during treatment, which is beneficial for the design of cost-effective treatment strategies.

We investigated the effect of hypoxic-anoxic range of dissolved oxygen (DO) on metal release/bioavailability at sediment-water interface (SWI) in the Ganga River. Here, we consider eight sites in the main river stem along 518 km; sixty sites downstream two point sources and two tributary confluences covering 630 km; and an incubation experiment to verify these results. We found higher concentrations of metals and bioavailable fractions at SWI at two locations of main stem and up to 700 m, 1000 m, 400 m and 500 m downstream Assi drain, Wazidpur drain, Ramganga confluence and Varuna confluence respectively where DO at SWI (DOₛw) was <2.0 mgL⁻¹. The incubation experiment did show higher levels of metal- and P-release and bioavailability under anoxic-hypoxic range of DO. The risk assessment code and eutrophication index indicated high to very high risks of contaminated river sediment and water to aquatic environment at sites with hypoxic-anoxic range of DOₛw. Further, the principal component analyses separated metals and bioavailable fractions opposite to FDAase indicating greater risk at these locations. The study, which forms the first report on benthic hypoxia/anoxia-driven metal release, potential bioavailability and risk to the Ganga River ecosystem will help understanding how human-driven perturbations influence geochemical cycling of metals and ecosystem responses in large rivers.

Environmentally persistent free radicals (EPFRs) are receiving increasing concern due to their toxicity and ubiquity in the environment. To avoid restrictions imposed when using a high-volume active sampler, this study uses tree leaves to act as passive samplers to investigate the spatial distribution characteristics and sources of airborne EPFRs. Tree leaf samples were collected from 120 sites in five areas around China (each approximately 4 km × 4 km). EPFR concentrations in particles (<2 μm) on the surface of 110 leaf samples were detected, ranging from 7.5 × 10¹⁶ to 4.5 × 10¹⁹ spins/g. For the 10 N.D. samples, they were all collected from areas inaccessible by vehicles. The g-values of EPFRs on 68% leaf samples were larger than 2.004, suggesting the electron localized on the oxygen atom, and they were consistent with the road dust sample (g-value: 2.0042). Significant positive correlation was found between concentrations of elemental carbon (tracer of vehicle emissions) and EPFRs. Spatial distribution mapping showed that EPFR levels in various land uses differed noticeably. Although previous work has linked atmospheric EPFRs to waste incineration, the evidence in this study suggests that vehicle emissions, especially from heavy-duty vehicles, are the main sources. While waste incinerators with low emissions or effective dust-control devices might not be an important EPFR contributor. According to our estimation, over 90% of the EPFRs deposited on tree leaves might be attributed to automotive exhaust emissions, as a synergistic effect of primary exhausts and degradation of aromatic compounds in road dust. With adding the trapping agent into the particle samples (<2 μm), signals of hydroxyl radicals were observed. This indicates that EPFRs collected from this phytosampling method can lead to the release of reactive oxygen species (ROS) once they are inhaled by human beings. Thus, this study helps highlight EPFR “hotspots” for potential health risk identification.