Plant uptake of cadmium (Cd) is affected by soil and environmental conditions. In this study, hydroponic experiments were conducted to investigate the effects of elevated CO₂ coupled with inoculated endophytic bacteria M002 on morphological properties, gas exchange, photosynthetic pigments, chlorophyll fluorescence, and Cd uptake of S. alfredii. The results showed that bio-fortification processes (elevated CO₂ and/or inoculated with endophytic bacteria) significantly (p < 0.05) promoted growth patterns, improved photosynthetic characteristics and increased Cd tolerance of both ecotypes of S. alfredii, as compared to normal conditions. Net photosynthetic rate (Pn) in intact leaves of hyperaccumulating ecotype (HE) and non-hyperaccumulating ecotype (NHE) were increased by 73.93 and 32.90%, respectively at the low Cd (2 μM), 84.41 and 57.65%, respectively at the high Cd level (10 μM). Superposition treatment increased Cd concentration in shoots and roots of HE, by 50.87 and 82.12%, respectively at the low Cd and 46.75 and 88.92%, respectively at the high Cd level. Besides, superposition treatment declined Cd transfer factor of NHE, by 0.85% at non-Cd rate, 17.22% at the low Cd and 22.26% at the high Cd level. These results indicate that elevated CO₂ coupled with endophytic bacterial inoculation may effectively improve phytoremediation efficiency of Cd-contaminated soils by hyperaccumulator, and alleviate Cd toxicity to non-hyperaccumulator ecotype of Sedum alfredii.

Polyurethane foam-based passive air sampler (PUF-PAS) and passive dry deposition sampler (PAS-DD) were adopted, for the first time ever in China, to investigate the atmospheric levels and spatial-temporal distributions of air burdens and dry deposition fluxes of 12 nitrated polycyclic aromatic hydrocarbons (NPAHs) during winter and summer seasons in a multiple site field campaign in a petrochemical industrialized capital city in Northwest China. The results showed that the highest air concentration and dry deposition fluxes of ∑₁₂NPAHs occurred at a heavy traffic site among 18 sampling sites in both winter and summer season. The lowest air concentration and dry deposition fluxes were observed at the background site. The mean concentrations of ∑₁₂NPAHs in the ambient air were 8.6 ± 8.1 ng m⁻³ in winter and 15 ± 11 ng m⁻³ in summer. The mean dry deposition fluxes of ∑₁₂NPAHs were 1.8 × 10³ ± 1.9 × 10³ ng (m² day)⁻¹ in winter and 1.4 × 10³ ± 1.3 × 10³ ng (m² day)⁻¹ in summer, respectively. The total concentration of 12 NPAHs was mainly dominated by 1-nitro-naphthalene (1N-NAP) and 2-nitro-naphthalene(2N-NAP) in air, accounting for 32% in winter and 45% in summer of ∑₁₂NPAHs. 7-Nitro-benzo [a] anthracene (7N-BaA) made the largest contribution to dry deposition fluxes of ∑₁₂NPAHs, accounting for 28% in winter and 24% in summer. The ratios of ∑₁₂NPAHs/∑₁₅pPAHs (parent polycyclic aromatic hydrocarbons) were calculated to identify potential sources of NPAHs across the city. The results revealed that the main atmospheric air concentration and dry deposition fluxes of 12 NPAHs could be attributed to the primary emissions in winter and the secondary reaction formation in summer. The sources of primary emissions could be traced back to petrochemical, steel mills, as well as aluminum industries in winter and vehicle exhaust in summer. Higher ∑₁₂NPAH/∑₁₅pPAH concentration ratios in summer indicated that the oxidation of pPAHs contributed to the secondary formation of NPAHs via atmospheric chemical reactions in this petrochemical industrialized mountain-valley city.

It is found that strong electronegative groups can selectively adsorb cellulose by hydrogen bonds. Grafting strong negatively charged groups onto catalysts to achieve the functionalization of the catalyst can give it the ability to selectively adsorb cellulose without affecting its catalysis, which is of great significance for the hydrolysis of cellulose. In this study, PTA@MIL-101–X (X = –Br, –NH₂, –Cl, –NO₂) materials were synthesized to investigate the effect of grafting different electronegative groups on carriers to the directional hydrolysis of cellulose. The synthesized catalysts used phosphotungstic acid as the catalytic center while treated MIL-101 structure as the carrier. The grafting of different electronegative groups changed the crystal structure of the metal organic framework without affecting its stability during the reaction. The strong negative functional groups can selectively adsorb cellulose by forming hydrogen bonds with cellulose hydroxyl groups and weaken the hydrogen bonds within cellulose molecules. This hydrogen bond can reduce the side reaction of glucose, lighten the difficulty of cellulose hydrolysis, and improve the efficiency of cellulose conversion at the same time. The hydrolysis rate of cellulose increased with the electronegativity enhancement of the grafted functional groups, and the grafted –NO₂ catalyst PTA@MIL-101–NO₂ obtained the highest glucose yield of 16.2% in the cellulose-directed hydrolysis. The –NH₂ can form a chemical linkage with PTA through electrostatic interaction to get the highest immobilization stability and exhibit excellent stability in the recycling of catalysts. Graphical abstract

To investigate how the organic fouling layers on nanofiltration (NF) membrane surface and the strong matrix effect (particularly by Ca²⁺) influence the rejection of trace organic compounds (TOrCs), filtration experiments with two TOrCs, bisphenol A (BPA) and sulfamethazine (SMT), were carried out with virgin and organic-fouled NF membrane. Organic fouling layer on the membrane was induced by sodium alginate (SA) at different concentrations of Ca²⁺. The results indicated that NF membrane maintained consistently rejection of TOrCs with little influence by membrane fouling at lower Ca²⁺ concentration. In contrast, organic fouling caused at higher concentration of Ca²⁺ observably restrained the rejections of both BPA and SMT. Furthermore, based on the cake-enhanced concentration polarization (CECP) model, the rejection of TOrCs was divided to the real rejection and the mass transfer coefficient. Moreover, it was found that the decrease in rejection resulted by organic fouling was due to the real rejection that was restrained by fouling layer with irregular impact on the mass transfer coefficient. Although the mechanism of trace compounds rejection was complex, the controlling factors varied among foulants. Nevertheless, the steric effect of the cake layer played an important role in determining solute rejection by organic-fouled NF membrane.

Chrysotile accounts for some 90% to 95% of all the asbestos used worldwide. Scientific evidences have shown that asbestos (including chrysotile) exposure is associated with increased rates of lung cancer, asbestosis, and mesothelioma. However, molecular mechanisms underlying the toxicity effects of chrysotile are not clear. This study evaluated the oxidative stress in chronic lung toxicity caused by the intratracheal instillation (IT) of four kinds China representative chrysotile once a month for 12 months in Wistar rats. These results indicated that chrysotile exposure led to an obvious increase in lung mass and slowed the growth of body mass. Inflammation and fibrosis were observed by hematoxylin-eosin (HE) staining. Exposure to chrysotile significantly increased the accumulation of reactive oxygen species (ROS) and the level of lipid peroxidation and decreased antioxidant capacity in lung tissues. Furthermore, 1–6-month chrysotile exposure activated heme oxygenase-1 (HO-1) and heat shock protein 70 (HSP70) expression, whereas 12-month exposure caused significant decreases of two-factor expression levels in XK and MN groups when compared to negative control group. Therefore, our results suggested that chronic chrysotile pulmonary injury in Wistar rats is triggered by oxidative damage. Meanwhile, the oxidative damage of MN and XK was stronger than that of SSX and AKS, and the difference of oxidative damage in four chrysotile could have been brought by its properties, morphology, chemical composition, and particle size. With all the above mentioned in view, we hope that the revealed data in the experiment could contribute to the progress of further researches on the toxicity and mechanism of chrysotile.

Acrylamide (AA) has been identified as probably carcinogenic to humans and thus represents a potential public health threat. This study aimed to determine the urinary concentrations of AA and N-acetyl-S-(2-carbamoylethyl)-L-cysteine (AAMA) in a nationally representative sample (n = 1025) of children and adolescents (age range 3–18 years) in South Korea. The AA and AAMA detection rates and geometric mean concentrations were 97%, 19.1 ng/mL, and 98.7%, 26.4 ng/mL, respectively. Although urinary AA levels did not vary widely by age (17.2 ng/mL at 3–6 years, 19.9 ng/mL at 7–18 years), the urinary concentration of AAMA increased with age (18.3 ng/mL at 3–6 years, 30.4 ng/mL at 7–18 years). A multiple linear regression analysis revealed that the urinary levels of AA and AAMA varied significantly by sex, with the adjusted proportional changes indicating rates of 1.47- to 1.48-fold higher at 3–6 years and 1.36- to 1.68-fold higher at 7–18 years among males relative to females. Furthermore, the urinary levels of AA and AAMA correlated with the consumption of certain foods (doughnuts, hotdogs, popcorn, and nachos) among male subjects aged 7–18 years. The urinary concentrations of AA and AAMA increased significantly with the smoking status and passive smoking exposure, with adjusted proportional changes of 1.51 to 1.71-fold higher among smokers relative to non-smokers in the age range of 7–18 years. Exposure to smoking for > 30 min led to adjusted proportional increases in AA and AAMA of 1.51 and 1.77 times in the non-smoking group aged 3–6 years and a 1.52-fold increase in AAMA in the non-smoking group aged 7–18 years. In conclusion, the urinary levels of AA and AAMA were found to associate with age, sex, smoking, and food consumption in a population of Korean children and adolescents.

Organic matter (OM), a complex entity with diverse functional groups and molecular sizes, has important effects on aquatic systems. We studied the optical compositions and sources of dissolved organic matter (DOM) and particulate organic matter (POM) in Lake Taihu, a large, shallow and eutrophic lake in China. Significant differences in optical compositions and sources occurred between the POM and DOM. The temporal–spatial distribution of the fluorescence indices suggested that the POM in Lake Taihu was mainly from autochthonous sources, but more exogenous characteristics were shown in POM in the river mouths compared with other regions. The chromophoric DOM in Lake Taihu mainly displayed autochthonous characteristics. The POM–DOM PARAFAC model was used to examine OM optical composition and five components were identified, which contained three protein-like components (C1, C2, and C5), a microbial humic-like component (C3), and a terrestrial humic-like component (C4). The POM was dominated by C5 in summer and autumn and C3 in winter and spring, and the DOM was dominated by protein-like components (C1, C2, and C5) through the entire year. The algae-dominated region had a relative higher contribution of tryptophan-like components of POM compared with the macrophyte-dominated region. A conceptual model based on the theory of “four phases of cyanobacteria bloom development” was proposed to fully describe the relationship between POM–DOM exchanges and cyanobacteria bloom development.

As much wind power is connected to the power system, the accommodation of the wind power in the power grids becomes a huge challenge to the operation model of China’s power system. Releasing and improving the flexibility of the power system will be necessary and important to enable the accommodation of power generated with renewable energy sources, which is connected to the power grids on a large scale and accounts for a high proportion. The paper, with North Hebei as an example, discusses the relationship between the demand for the flexibility of thermal power units and the accommodation of wind power. This paper further analyzes the demand for peak load regulation in North Hebei at both the present and the future as well as the characteristics of power sources in the power grids of North Hebei and the technical potential of power generation. It also compares the quantity of curtailed power before and after the flexibility-oriented transformation of thermal power units in North Hebei and calculates the minimum technical output of thermal power under different levels of accommodation of wind power. The research shows that the peak load regulating resources in the power grids of North Hebei boast huge potential, but in the long term, to achieve the objective of a 10% curtailment rate of power generated with renewable energy sources, the minimum technical output of condensing units must be lower than the internationally advanced level of 25%. So, it is difficult to fulfill the said objective solely relying on the strengthened transformation of generating units. To reach the level of 5% curtailment rate of power generated with renewable energy sources, the minimum technical output must achieve breakthrough improvement, which requires continuous technological innovation and power flexibility in close coordination.

Many researchers have focused on controlling pest insects and vectors by natural products because of their low environmental pollution. The present study was conducted to evaluate the antioxidant and larvicidal activities of chloroform and methanol extracts of the leaves, fruits, roots, and isolated coumarin compounds (prantschimgin, oxypeucedanin, and 6-hydroxymethylherniarin) of Ferulago trifida from the Apiaceae family against Anopheles stephensi as one of the main malaria vectors. For insecticidal evaluation, A. stephensi larvae were exposed to different concentrations of the extracts and pure compounds (0.625–1280 ppm) according to the WHO protocol. The mortality percentages were measured 24 h after treatment and lethal concentration values were calculated. In addition, radical scavenging activities of the mentioned extracts and compounds were measured by the DPPH method. The methanol extract of fruits showed potent insecticidal properties with LC₅₀ and LC₉₀ values of 2.94 and 18.12 ppm, respectively. The chloroform extracts of the fruits and leaves were the second and third extracts with larvicidal effects. Among pure compounds, only oxypeucedanin showed moderate toxicity against A. stephensi with LC₅₀ and LC₉₀ values of 116.54 and 346.41 ppm, respectively. The antioxidant activities of the methanol extracts of leaves and fruits were stronger than other extracts with IC₅₀ values of 155.83 and 159.32 ppm, respectively. In conclusion, the methanol extract of F. trifida fruits can be used as a potent bio-insecticide in green control programs of mosquitoes, especially A. stephensi.