Although the Chinese government emphasizes the significance of public transportation development and encourages green travel, no empirical study has examined whether the expansion of public transportation facilitates the mitigation of carbon emissions. To this end, we employ a panel quantile regression to test the endogenous relationship between public transportation scale and carbon emissions. The results suggest that the effect of public transportation scale on carbon emissions is heterogeneous across China’s provinces based on the level of carbon emissions. Even so, the results still support a stable inverted U-shaped relationship between public transportation scale and carbon emissions for provinces with different levels of carbon emissions. That is, when public transportation scale exceeds a threshold value, the relationship between public transportation and carbon emissions will turn from positive to negative. Our findings provide evidence advocating for public transportation development and green travel. It is of great significance for China to respond to climate changes.

The tailings produce acid mine drainage (AMD) due to sulfide minerals, especially pyrite oxidation. AMD has caused serious pollution to the surrounding aquatic and terrestrial ecosystems because of its famous low pH value and high metal and sulfate concentration, which is an urgent environmental problem faced by the world’s ore mining industry. Here, we show that silicic protective surface films can suppress the oxidation of pyrite-bearing tailings for AMD control at-source without pre-oxidation of pyrite and solution pH adjuster and buffer. We found that the silicic protective surface films formed by calcium silicate can inhibit the oxidation of pyrite-bearing tailings and reduce the production of AMD through chemical leaching tests. Fourier transform infrared (FTIR) analyses and scanning electron microscopy with energy-dispersive spectrometry (SEM/EDS) confirmed the presence of silicic protective surface films of calcium silicate on the surface of pyrite-bearing tailings.

Hand, foot, and mouth disease (HFMD) is a viral illness that is considered a critical public health challenge worldwide. Previous studies have demonstrated that meteorological parameters are significantly related to the incidence of HFMD in children; however, few studies have focused only on female children. This study quantified the associations of HFMD incidence with meteorological parameters and PM₁₀ (particulate matter with an aerodynamic diameter of 10 μm) among female children. Data were collected on daily HFMD cases, meteorological variables, and PM₁₀ levels in Ningbo, China, from January 2012 to December 2016. Data were assessed using a distributed lag nonlinear model (DLNM) with Poisson distribution. A total of 59,809 female children aged 0−15 years with HFMD were enrolled. The results showed that highest relative risk (RR) of HFMD for temperature was 3 °C and the lag effect was 3 days. The highest RR for PM₁₀ was 80 mg/m³ and the lag effect was 5 days. Spatial analysis showed that female HFMD incidence was mainly concentrated in the suburban of Ningbo city indicating that female children in this area should be more paid attention on avoiding this disease outbreak. Our findings suggest that HFMD prevention strategies should focus more attention on local meteorological parameters.

Chromium is used in daily life and has a wide range of functions. It plays an important role in protein synthesis and carbohydrate and lipid metabolism. Chromium is found in trivalent Cr(III) and hexavalent Cr(VI) form; Cr(III) is relatively stable and intimately participates with many phenomena of metabolisms. Whereas, Cr(VI) is toxic, which results in growth inhibition and leading to changes in components of antioxidant systems as well as secondary metabolites. However, the molecular mechanism that is involved in Cr (VI)-induced hepatotoxicity is still unclear. For this purpose, 40 chickens were randomly assigned into two groups: the normal group (feeding the basic diet and clear water), the chromium group (16%LD₅₀, 74.24 mg/kg/day K₂Cr₂O₇). The samples were subjected to pathological examination and UHPLC-QE-MS non-target metabolomics method for metabolomics analysis of broiler liver using principal component analysis (PCA) and partial least squares discriminant analysis (OPLS-DA). The central venous cells of the broiler liver in the chromium poisoning group showed turbidity and flaky necrosis, nuclear condensation, nuclear rupture, and even nuclear dissolution. The differential metabolite analysis between the chromium poisoning and the control group showed that 32 differential metabolites were upregulated and 15 were downregulated in positive ion mode. Whereas,17 differential metabolites were downregulated, and 35 were downregulated in negative ion mode (P ≤ 0.05). The potential marker substances are oleic acidamide, farnesylacetone, betaine, taurine, choline, and galactinol. Additionally, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways showed that the lipid metabolism, carbohydrate metabolism, nucleotide metabolism, amino acid metabolism, energy metabolism, membrane transport, digestive system, and nervous system were the most important metabolic pathways in the liver. This study provides a theoretical basis for the future understanding of the pathogenesis of chromium poisoning and a new insight of the subsequent molecular mechanism of chromium hepatotoxicity.

Organic contamination in freshwater samples has never been investigated at the western shore of Admiralty Bay. Therefore, the presence of polycyclic aromatic hydrocarbons (PAHs) in five different sites distributed along a shore running from the Arctowski Station to the Baranowski Glacier was studied. Moreover, organic compounds such as n-alkanes, toluene and ethylbenzene were also noted. Increased ΣPAHs in late Austral summer 2016 are the result of long-range atmospheric transport of air masses from South America, confirmed by 10-day backward air mass trajectories analysis. The presence of n-alkanes and other hydrocarbons, as well as the evaluation of PAH indices (e.g. ΣLMW/ΣHMW* > 1), shows the use of fuel and indicate local human activity. As a final conclusion, our analysis indicates a mixed origin of PAHs (global and local). The presence of PAHs and other hydrocarbons in the water environment may constitute a potentially negative effect on the Antarctic ecosystem and it should be investigated in detail during further research (//*ΣLMW—sum of low molecular weight PAHs (two- and three-ring PAHs); ΣHMW—sum of high molecular weight PAHs (four- and five-ring PAHs)//). Graphical abstract

Wheat straw is an abundant agricultural waste that is rich in lignocellulose. However, its waxy surface, highly crystallized structure, and limited surface area make it difficult to be hydrolyzed and used efficiently by microorganisms. Liquid hot water (LHW) pretreatment was studied to explore the feasibility of improving the methane yield of wheat straw in anaerobic digestion (AD). The results showed that the crosslinking structure of wheat straw was broken by LHW pretreatment. Some pores and cracks appeared on the surface of the pretreated wheat straw, increasing the microbial attachment sites. Under different hydrothermal temperatures (150–225 °C) and retention times (5–60 min), the degradation of hemicellulose ranged from 27.69 to 99.07%. The maximum methane yield (201.81 mL CH₄/g volatile solids) was achieved after LHW pretreatment at 175 °C for 30 min, which was a 62.9% increase compared with non-treated straw. LHW at high temperatures such as 225 °C was not suitable for the AD of wheat straw. Methane yield results were fitted with the first-order and modified Gompertz equations to evaluate the hydrolysis rate and inhibitory effects of the pretreated materials in AD.

Environmental pollution analysis should be present in scientific research. The more organized the environmental laws of a particular place, the smaller the risks imputed to the ecosystem. The environmental damages that irregular waste from industrial effluents can cause are notorious. However, Brazil lacks extensive legal regulation, which is an embryonic legal matter. There is no specific law regulating a National Industrial Effluent Policy, dealing with the treatment and final disposal of these chemical compounds. Until a solid legal structure has been formalized on the treatment and final disposal of industrial effluents in Brazil, it is necessary that scientific researches optimize techniques capable of causing lower environmental impacts, so as to avoid possible pollution to the bodies of water. This article defends the argument that it is possible to elaborate legislation on the treatment and final disposal of industrial effluents in Brazil, through the application of engineering techniques, specifically through numerical simulation, by using the discrete elements method or particles method. The present case study is the Camaçari Petrochemical Pole, state of Bahia, which is the largest integrated industrial complex in the Southern Hemisphere, composed of more than 90 companies in the chemical and petrochemical areas. All the effluents from this locality are treated by CETREL (Liquid Effluent Treatment Plant). Particle analysis was performed in CETREL tanks to illustrate how numerical simulations can be applied to investigate the treatment of industrial effluents and, consequently, to affirm the importance of developing procedures and norms for this matter. It is believed that this article brings relevant information to support a future law that regulates a Brazilian National Policy of Industrial Effluents.

The removal of Acid Orange 51 (AO 51) dye in aqueous solution by microscale zero-valent iron (m-ZVI) was investigated. The m-ZVI powder was characterized granulometrically by laser particle sizer and morphologically by transmission electron microscopy (TEM). The effects of pH, m-ZVI concentration, H₂O₂ addition, and dye concentration on the decolorization of AO 51 were experimentally investigated. Results indicate that the removal efficiency is independent from pH values, increases with increasing ZVI dosage, and decreases with dye concentration. With 1 g/L of m-ZVI, AO 51 was effectively removed without and with addition of 25 mM H₂O₂, yielding a decolorization efficiency of around 70% and 98%, respectively, at pH 3 within 60 min of reaction time. The involvement of ˙OH in oxidizing AO 51 was examined by measuring the removal rates based on ˙OH scavenging molecule. Finally, the disappearance of AO 51 was estimated by monitoring the UV–Vis spectral evolution after 120 min of treatment while the Fourier-Transform Infrared spectroscopy (FT-IR) was performed to verify the occurrence of organic sorption on m-ZVI surface. The scanning electron microscope (SEM) images before and after the reaction illustrated morphological changes on m-ZVI surface. The detoxification of the treated solution was demonstrated using phytotoxicity test.

Mechanochemical degradation (MCD) technology has shown its remarkable potential in the disposal of persistent organochlorines in a non-combustion manner. In the present study, endosulfan, as the newly listed persistent organic pollutants (POPs) in the Stockholm Convention, was investigated for its feasibility of mechanochemical destruction using high-energy ball milling. Using calcium oxide (CaO) as a co-milling reagent, the degradation efficiency of endosulfan was nearly 100% after ball milling for 60 min, while the dechlorination efficiency and the sulfate formation efficiency were delayed for endosulfan degradation. After ball milling for 120 min, the dechlorination efficiency and sulfate formation efficiency reached 87.55% and 26.28%, respectively. Based on the measurement results from various material characterization approaches, the main degradation pathway of endosulfan was proposed as sequential dechlorination followed by the destruction of hydrocarbon skeleton. The GC-MS analysis confirmed that complete desulfurization and dechlorination had been realized finally. This study provides an option for the way toward the efficient and rapid destruction of endosulfan as a new POPs using mechanochemical technology.

Sediments are reservoirs and sources of DDTs to the aquatic ecosystem. However, the role of sediment particulate matter and benthic organisms in transferring DDTs remains unclear. In this study, microcosms were built up with different groups to simulate a freshwater system with DDT-contaminated sediment and organisms. The impacts of different exposure routes (water and sediment) on the changes of DDT and its metabolites (DDD and DDE) in carp (Cyprinus carpio) were investigated. The bioturbation of Tubifex tubifex (Oligochaeta, Tubificidae) was investigated to understand the fate and transfer of DDTs in aquatic environment. For the sediment treatment, the concentrations of o,p’-DDT in carp were significantly higher than those of p,p’-DDT, and the metallothionein (MT) content decreased. The bioaccumulation of DDTs in carp via sediment particulate matter was significantly higher/faster than that via overlying water. T. tubifex and sediment particulate matter accelerate DDT bioaccumulation in carp. Selective enrichment of the (+)-o,p’-DDT and (+)-o,p’-DDD was found in carp. These results help to reduce uncertainty in ecological and health risk assessments and to better understand the risk of DDTs in the environment.