Air pollution has been identified as a major cause of environmental and human health damage. O₃ is an oxidative pollutant that causes leaf symptoms in sensitive plants. This study aims to adjust a multilinear model for the monitoring of O₃ in subtropical climatic conditions by associating O₃ concentrations with measurements of morphological leaf traits in tobacco plants and different environmental variables. The plants were distributed into five areas (residential, urban or industrial) in the southern region of Brazil and exposed during 14 periods, of 14 days each, during the years of 2014 and 2015. The environmental variables and leaf traits during the exposure periods were described by mean, median, standard deviation and minimum and maximum values. Spearman correlation and multiple linear regression analyses were applied on data from exposure periods. Leaf injury index, leaf area, leaf dry mass, temperature, relative humidity, global solar radiation and accumulated rainfall were used in the regression analyses to select the best models for predicting O₃ concentrations. Leaf injury characteristically caused by O₃ was verified in all areas and periods of plant exposure. Higher values of leaf injury (24.5% and 27.7%) were registered in the 13th and 12th exposure periods during spring and in areas influenced by urban and industrial clutches. The VPD, temperature, global solar radiation and O₃ were correlated to leaf injury. Environmental variables [leaf area, leaf dry mass, global solar radiation and accumulated rainfall] and primarily the VPD were fundamental to improve the adjustments done in the bioindicator model (R² ≥ 0.73). Our research shows that biomonitoring employing the tobacco “Bel-W3” can be improved by measuring morphological leaf traits and meteorological parameters. Additionally, O₃ fumigation experiment should be performed with biomonitoring as conducted in this study, which are useful in understanding the role of other environmental factors.

In the era of big data, a variety of factors (particularly meteorological factors) have been applied to PM2.5 concentration prediction, revealing a clear discrepancy in timescale. To capture the complicated multi-scale relationship with PM2.5-related factors, a novel multi-factor & multi-scale method is proposed for PM2.5 forecasting. Three major steps are taken: (1) multi-factor analysis, to select predictive factors via statistical tests; (2) multi-scale analysis, to extract scale-aligned components via multivariate empirical mode decomposition; and (3) PM2.5 prediction, including individual prediction at each timescale and ensemble prediction across different timescales. The empirical study focuses on the PM2.5 of Cangzhou, which is one of the most air-polluted cities in China, and indicates that the proposed multi-factor & multi-scale learning paradigms statistically outperform their corresponding original techniques (without multi-factor and multi-scale analysis), semi-improved variants (with either multi-factor or multi-scale analysis), and similar counterparts (with other multi-scale analyses) in terms of prediction accuracy.

Some basic research has shown that nanomaterials can aggravate allergic asthma. However, its potential mechanism is insufficient. Based on the research that alumina nanopowder (nAl2O3) has been reported to cause lung tissue damage, the purpose of this study was to explore the relationship between nAl2O3 and allergic asthma as well as its molecular mechanism. In this study, Balb/c mice were sensitized with ovalbumin (OVA) to construct the allergic asthma model while intratracheally administered 0.5, 5 or 50 mg kg−1·day−1 nAl2O3 for 3 weeks. It was observed that exposure to nAl2O3 exacerbated airway hyperresponsiveness (AHR), airway remodeling, and inflammation cell infiltration, leading to lung function damage in mice. Results revealed that nAl2O3 could increase ROS levels and decrease GSH levels in lung tissue, promote the increases of the T-IgE, TGF-β, IL-1β and IL-6 levels, stimulate the overexpression of transcription factors GATA-3 and RORγt, decrease the levels of IFN-γ and IL-10 and increase the levels of IL-4 and IL-17A, resulting in the imbalance of Th1/Th2 and Treg/Th17 immune responses. In addition, antioxidant Vitamin E (Vit E) could alleviate asthma-like symptoms through blocking oxidative stress. The study displayed that exposure of nAl2O3 deteriorated allergic asthma through promoting the imbalances of Th1/Th2 and Treg/Th17.

Inhalation exposure to atmospheric polycyclic aromatic hydrocarbons (PAHs) is posing a great threat to human health. Biomass combustion in rural areas contributes greatly to the total PAH emission in China. To conduct a comprehensive risk assessment of ambient PAHs in rural China, a nationwide air sampling campaign was carried out in this study. The 16 U.S. Environmental Protection Agency priority PAHs in tree bark, which was employed as a passive air sampler, were analyzed. The summation of the 16 PAHs ranged from 11.7 to 12,860 ng/m³ in the air of rural China. The national median benzo(a)pyrene equivalent (BaPₑq) concentration was 18.4 ng/m³, with the range from 0.334 to 2497 ng/m³. The total inhalation carcinogenic risks of individual PAHs, with the exception for naphthalene, were very low (<1 × 10⁻⁶) at most of the sampling sites. The national median excess lifetime lung cancer risk associated with inhalation exposure to atmospheric PAHs was 20.3 × 10⁻⁶, corresponding to a population attributable fraction (PAF) of 3.38‰. Our estimations using tree bark were comparable to those reported in other studies and the uncertainties of the variables in the dataset were within the acceptable levels, demonstrating that tree bark is feasible for assessing the atmospheric PAH pollution and associated health risks. We feel that the outputs from this study can assist decision-makers focusing on protecting human health against exposure to atmospheric PAHs in rural China.

The efficient removal of mercury from aqueous media remains a severe challenge in ensuring environmental safety, especially for low-concentration mercury, which requires adsorbents with high mercury affinity. In this work, we reported a nanocomposite of β-cyclodextrin and three-dimensional graphene (3D CD@RGO) to enhance the adsorption affinity and capacity for mercury with low concentrations. Characterization of the nanocomposite revealed that cyclodextrin was well dispersed on the 3D graphene support structure to provide highly exposed hydroxyl groups. Adsorption experiments showed that CD@RGO exhibited different adsorption behaviors for mercury within different concentration ranges of 0.2–4.0 mg/L and 4.0–10.0 mg/L, and the adsorption affinity for the former range (KL = 10.05 L/mg) was 1.5 times higher than that for the latter range (KL = 6.69 L/mg). Moreover, CD@RGO had a high adsorption efficiency of 96.6% with a superb adsorption affinity (172.09 L/g) at Ce = 0.01 mg/L, which is 6.70 and 41.25 times higher than that of RGO and RCD (physical mixture of RGO and cyclodextrin), respectively, indicating a synergistic effect of CD@RGO for mercury adsorption. This enhancement can be attributed to the transformation of the adsorption mechanism from the outer-sphere force of electrostatic interaction in RGO to the inner-sphere surface complexation in CD@RGO.

Antibiotics enter into aquatic pond sediments by wastewater and could make detrimental effects on microbial communities. In this study, we examined the effects of sulfadimidine on nitrogen removal when added to experimental pond sediments. We found that sulfadimidine increased the number of sulfadimidine resistant bacteria and significantly increased the abundance of sul2 at the end of the incubation time (ANOVA test at Tukey HSD, P < 0.05). In addition, sulfadimidine decreased the N₂O reduction rate as well as the amount of nitrate reduction. Pearson correlation analysis revealed that the N₂O reduction rate was significantly and negatively correlated with narG (r = −0.679, P < 0.05). In contrast, we found a significant positive correlation between the amount of nitrate reduction and the abundance of narG (r = 0.609, P < 0.05) and nirK (r = 0.611, P < 0.05). High-throughput sequencing demonstrated that Actinobacteria, Euryarchaeota, Gemmatimonadetes, Nitrospirae, Burkholderiaceae (a family of Proteobacteria), and Thermoanaerobaculaceae (a family of Firmicutes) decreased with sulfadimidine exposure. In sediments, Actinobacteria, Bacteroidetes, Cyanobacteria, Epsilonbacteraeota, Euryarchaeota, Firmicutes, Gemmatimonadetes, and Spirochaetesat may play key roles in nitrogen transformation. Overall, the study exhibited a net effect of antibiotic exposure regarding nitrogen removal in an aquatic microcosm environment through a combination of biochemical pathways and molecular pathways, and draws attention to controlling antibiotic pollution in aquatic ecosystems.

As the second largest economy in the world, China experiences severe particulate matter (PM) pollution in many of its cities. Meteorological factors are critical in determining both areal and temporal variations in PM pollution levels; understanding these factors and their interactions is critical for accurate forecasting, comprehensive analysis, and effective reduction of this pollution. This study analyzed areal and temporal variations in concentrations of PM₂.₅, PM₁₀, and PMcₒₐᵣₛₑ (PM₁₀ - PM₂.₅) and PM₂.₅ to PM₁₀ ratios (PM₂.₅/PM₁₀) and their relationships with meteorological conditions in 366 Chinese cities from January 1, 2015 to December 31, 2017. On the national scale, PM₂.₅ and PM₁₀ decreased from 48 to 42 μg m⁻³ and from 88 to 84 μg m⁻³, respectively, and the annual mean concentrations were 45 μg m⁻³ (PM₂.₅) and 84 μg m⁻³ (PM₁₀) during the time period (2015–2017). In most regions, largest PM concentrations occurred in winter. However, in northern China, in spring PMcₒₐᵣₛₑ concentrations were highest due to dust. The PM₂.₅/PM₁₀ ratio was higher in southern than in northern China. There were large regional disparities in PM diurnal variations. Generally, PM concentrations were negatively correlated with precipitation, relative humidity, air temperature, and wind speed, but were positively correlated with surface pressure. The sunshine duration showed negative and positive impacts on PM in northern and southern cities, respectively. Meteorological factors impacted particulates of different size differently in different regions and over different periods of time.

Lipophilic marine toxins in shellfish pose significant threats to the health of seafood consumers. To assess the contamination status of shellfish by lipophilic marine toxins in the Bohai Sea, nine species of shellfish periodically collected from five representative aquaculture zones throughout a year were analyzed with a method of liquid chromatography-tandem mass spectrometry (LC–MS/MS). Lipophilic marine toxins, including okadaic acid (OA), dinophysistoxin-1 (DTX1), pectenotoxin-2 (PTX2), yessotoxin (YTX), homo-yessotoxin (homo-YTX), azaspiracids (AZA2 and AZA3), gymnodimine (GYM), and 13-desmethyl spirolide C (13-DesMe-C), were detected in more than 95 percent of the shellfish samples. Toxins PTX2, YTX, 13-DesMe-C and GYM were predominant components detected in shellfish samples. Scallops, clams and mussels accumulated much higher level of lipophilic marine toxins compared to oysters. Toxin content in shellfish samples collected from different sampling locations showed site-specific seasonal variation patterns. High level of toxins was found during the stages from December to February and June to July in Hangu, while from March to April and August to September in Laishan. Some toxic algae, including Dinophysis acuminata, D. fortii, Prorocentrum lima, Gonyaulax spinifera and Lingulodinium polyedrum, were identified as potential origins of lipophilic marine toxins in the Bohai Sea. The results will offer a sound basis for monitoring marine toxins and protecting the health of seafood consumers.

The present study investigated the beneficial role of selenium-nanoparticles (Se-NPs) in mitigating the adverse effects of soil-salinity on growth and yield of strawberry (Fragaria × ananassa Duch.) plants by maneuvering physiological and biochemical mechanisms. The foliar spray of Se-NPs (10 and 20 mg L⁻¹) improved the growth and yield parameters of strawberry plants grown on non-saline and different saline soils (0, 25, 50 and 75 mM NaCl), which was attributed to their ability to protect photosynthetic pigments. Se-NPs-treated strawberry plants exhibited higher levels of key osmolytes, including total soluble carbohydrates and free proline, compared with untreated plants under saline conditions. Foliar application of Se-NPs improved salinity tolerance in strawberry by reducing stress-induced lipid peroxidation and H₂O₂ content through enhancing activities of antioxidant enzymes like superoxide dismutase and peroxidase. Additionally, Se-NPs-treated strawberry plants showed accumulation of indole-3-acetic acid and abscisic acid, the vital stress signaling molecules, which are involved in regulating different morphological, physiological and molecular responses of plants to salinity. Moreover, the enhanced levels of organic acids (e.g., malic, citric and succinic acids) and sugars (e.g., glucose, fructose and sucrose) in the fruits of Se-NPs-treated strawberry plants under saline conditions indicated the positive impacts of Se-NPs on the improvement of fruit quality and nutritional values. Our results collectively demonstrate the definite roles of Se-NPs in management of soil salinity-induced adverse effects on not only strawberry plants but also other crops.

We have previously reported on the ubiquitous presence of perchlorate in the deposited and airborne fine dusts of Malta and shown that the source of the chemical in the dusts of this small central Mediterranean island is fireworks. There are no local geologic or anthropogenic sources of perchlorate other than firework manufacture and display. The hypothesis was tested that ground-deposited perchlorate will be mobilized in runoff and would partly migrate to the water table and eventually also affect tap water, one third of which being derived from groundwater. Forty four percent of 36 groundwater samples contained perchlorate above detection limit with mean and median values of 1.09 and 1.1 μg L−1. Sixty-two percent of 16 runoff samples collected during storms contained perchlorate above detection limit with mean and maximum concentrations, respectively, of 50.8 and 129 μg L−1, values which are far too high to be explained by atmospheric inputs given that rainwater perchlorate levels are typically <3 μg L−1. Between 42 and 89% of the tap waters analyzed in three sampling campaigns contained perchlorate above detection limit and had mean concentrations ranging from 0.4 to 1.6 μg L−1 suggesting contamination levels similar to those reported from China but lower than levels reported from the USA. The phenomenon of contamination of the water resources of Malta by perchlorate is probably unique in that it results not from geologic or industrial inputs but from an intense and prolonged pyrotechnic activity that is deeply rooted in the popular culture of the islanders.