Enhancement of phytoextraction efficiency coupling Pteris vittata with low-dose biochar in arsenic-contaminated soil.

Phytoremediation of arsenic (As) by Pteris vittata (P. vittata) is a cost-effective and environmentally friendly method for restoring As-contaminated sites. However, the phytoextraction efficiency is low in some cases, such as clay soil, thus biochar was applied to enhance the efficiency of As extraction. The paper investigated the effect of biochar on soil characteristic, As mobility, and As uptake in P. vittata with a 90-day greenhouse experiment. Biochar derived from rice straw was added at rates of 0.5, 1.5, and 4% (w/w). The results showed that, under biochar amendment, soil pH raised from 5.24 to 6.03 and 4.91 to 5.85, soil dissolved organic carbon (DOC) increased 11.1-46.1% and 2.8-11.2%, respectively, in rhizosphere and bulk soils. Biochar also increased soil catalase (CAT) activity significantly, especially for the rhizosphere soil. Besides, biochar increased the labile As in the soils and transfer coefficient from roots to aboveground, thereby enhancing As accumulation by P. vittata tissues. The accumulation of As in fronds of P. vittata was up to 350 mg kg-1 in 1.5% biochar, which was more than twice the control and far beyond other biochar treatments. The results indicate that biochar addition is favorable to improve phytoremediation of P. vittata in As-contaminated soil and 1.5% (w/w) biochar may be a reasonable application ratio, thus providing an effective solution to enhance the efficiency of As phytoextraction.

Biochar increased soil catalase activity in the rhizosphere of P. vittata.Biochar increased the labile concentration of arsenic in soil and arsenic accumulation in P. vittata significantly.Combining biochar and P. vittata reduced arsenic in soil.Biochar amendment was favorable for phytoremediation of P. vittata in arsenic-contaminated soil.

Pathway and Cost-Benefit Analysis to Achieve China's Zero Hydrofluorocarbon Emissions.

Global hydrofluorocarbon (HFC) cumulative emissions will be more than 20 Gt CO2-equiv during 2020-2060 and have a non-negligible impact on global warming even in full compliance with the Kigali Amendment (KA). Fluorochemical manufacturers (including multinationals) in China have accounted for about 70% of global HFC production since 2015, of which about 60% is emitted outside China. This study built an integrated model (i.e., DECAF) to estimate both territorial and exported emissions of China under three scenarios and assess the corresponding climate effects as well as abatement costs. Achieving near-zero territorial emissions by 2060 could avoid 23 ± 4 Gt CO2-equiv of cumulative territorial emissions (compared to the 2019 Baseline scenario) during 2020-2060 at an average abatement cost of 9 ± 6 USD/t CO2-equiv. Under the near-zero emission (including territorial and abroad) pathway, radiative forcing from HFCs will peak in 2037 (60 ± 6 mW/m2) with a 33% peak reduction and 8 years in advance compared to the path regulated by the KA, and the radiative forcing by 2060 will be lower than that in 2019. Accelerated phase-out of HFC production in China could provide a possibility for rapid global HFC abatement and achieve greater climate benefits.

Atmospheric Observation and Emission of HFC-134a in China and Its Four Cities.

1,1,1,2-Tetrafluoroethane (HFC-134a) is widely used as a refrigerant to replace dichlorodifluoromethane (CFC-12), and a small amount of it is used in the foam and medical aerosol sectors, with a high global warming potential and fast-increasing atmospheric concentration. The emission of HFC-134a in China has been growing at an average annual growth rate of 14.4% since 2009, reaching 53.0 (47.5-58.7) kt yr-1 in 2020. Among the five emission sources, emissions from the mobile air conditioning (MAC) sector accounted for the highest proportion of 65% on average of the total, followed by the commercial air conditioning (CAC) sector (25%), the medical aerosols sector (8%), the foam sector (2%), and leakage emission from the production (less than 0.1%). The emissions of HFC-134a in four cities in China (Beijing, Guangzhou, Hangzhou, and Lanzhou) were also estimated and discussed. Beijing had the highest HFC-134a emission of 2.2 kt yr-1 in 2020, and Lanzhou had the lowest emission of only 0.2 kt yr-1. In Beijing and Guangzhou, emissions from the CAC sector surpassed those from the MAC sector, becoming the most important source of HFC-134a. The average annual growth rate of HFC-134a's emissions during 2009-2019 was close to its concentration enhancement growth rate of 12.7%, and the emissions also showed significant correlations with the concentration enhancements in both China and four cities. This indicates the importance of the muti-city and long-term observations for the verification of HFC-134a's emission estimates at a regional scale.

Singlet oxygen production abilities of oxidated aromatic compounds in natural water.

Singlet oxygen (1O2) is well known to be formed through energy transfer from excited state organic matters to O2, playing an important role in the transformations of contaminants. However, the contribution of small oxidated aromatic compounds (OACs) to the production of 1O2 in surface water is unclear. In this study, 28 OACs were selected to investigate the correlations between their photochemical production abilities of 1O2 and molecular structures. Our results showed that the steady-state concentrations and quantum yields of 1O2 (Φ1O2) generated by OACs were in the range of 7.0 × 10-14-1.4 × 10-12 M and 2.2 × 10-4-4.7 × 10-2, respectively, indicating that the photochemical production abilities of 1O2 by OACs varied greatly with types and positions of functional groups on the molecule. More importantly, the observed photochemical production of 1O2 was most notable in cases of molecules containing -OCH3 group and benzoquinone. A good quantitative structure-property relationship model was established between 1O2 producing ability, energy of the lowest unoccupied molecular orbitals (ELUMO) and the most positive net charge of hydrogen atoms (qH+) of OACs. In addition, the role of 1O2 produced by 2, 6-dimethoxy-1, 4-benzoquinone, the OAC with the highest Φ1O2, in the photodegradation of organic contaminants was validated by the enhanced degradation of atorvastatin under simulated sunlight, suggesting that OACs ubiquitously existed in surface water may greatly affect the fate and ecological risks of organic contaminants.

Gentianella turkestanerum Showed Protective Effects on Hepatic Injury by Modulating the Endoplasmic Reticulum Stress and NF-κB Signaling Pathway.

OBJECTIVE: To investigate the protective effects of Gentianella turkestanerum extraction by butanol (designated as GBA) on hepatic cell line L02 injury induced by carbon tetrachloride (CCl4) and hydrogen peroxide (H2O2). METHODS: L02 cells were incubated with 5 µg/mL, 10 µg/mL, 20 µg/mL, 40 µg/mL, 60 µg/mL, 80 µg/mL and 100 µg/mL GBA for 24 hours, and then MTT assay was used to screen the cytotoxicity for GBA. Cells were divided into blank control group, CCl4/H2O2 model group, treated by CCl4 (20 mmol/L) or H2O2 (100 µmol/L); silymarin+CCl4/H2O2 group, treated by CCl4 (20 mmol/L) or H2O2 (100 µmol/L) and 5 µg/mL silymarin; GBA+CCl4/H2O2 group, treated by CCl4 (20 mmol/L) or H2O2 (100 µmol/L) and GBA (5 µg/mL, 10 µg/mL and 20 µg/mL). MTT assay was performed to determine the cellular activity. Malondialdehyde (MDA) content was determined using a commercial kit. The alanine transaminase (ALT), aspartate transaminase (AST) in the supernatant was determined. PE-Annexin V/7-ADD method was utilized to determine the apoptosis of cells. RT-PCR was used to evaluate the expression of endoplasmic reticulum stressrelated genes (CHOP, PERK, IRE1 and ATF6) mRNA. Western blot analysis was performed to determine the expression of CHOP, Caspase 12 and NF-κB protein. RESULTS: Cellular survival after GBA (5 µg/mL, 10 µg/mL and 20 µg/mL) incubation was ≥ 75%. After GBA incubation, levels of ALT and AST showed a significant decrease (P < 0.05), while that of the MDA showed a significant decrease (P < 0.05). The apoptosis in the CCl4 or H2O2 group showed a significant increase compared to the control group (P < 0.05). In contrast, GBA-preincubation could attenuate the cellular apoptosis compared to the CCl4 or H2O2 group, which displayed a dose-dependent manner (P < 0.05). The expression of CHOP, PERK, IRE1 and ATF6 mRNA was significantly up-regulated in the presence of CCl4 or H2O2 (P < 0.05). Whereas, GBA induced a significant decrease in these mRNA thereafter (P < 0.05), together with a decrease in CHOP and Caspase 12 proteins (P < 0.05). Besides, it could attenuate the expression of NF-κB p65 in nuclear protein. CONCLUSION: G. turkestanerum could inhibit the lipid peroxidation and increase the antioxidant activity. Also, it could inhibit the cellular apoptosis through down-regulating the transcriptional level of ERS related genes and proteins. This process was associated with the nuclear translocation of NF-κB p65 protein.