Carboxymethyl cellulose/poly(acrylic acid) (CMC-cl-pAA) hydrogel and its magnetic hydrogel nanocomposite (CMC-cl-pAA/Fe₃O₄-C30B) were prepared via a free radical polymerization method and used as adsorbents for adsorption of methylene blue (MB) dye. The samples were characterized using Fourier transform infrared, X-ray diffraction, thermogravimetric analysis, scanning electron microscopy coupled with energy-dispersive X-ray spectrometer, high-resolution transmission electron microscope, and dynamic mechanical analysis. The adsorption performance of the prepared adsorbents was studied in a batch mode. Adsorption kinetics and isotherm models were applied in the experimental data to evaluate the nature as well as the mechanism of adsorption processes. It was deduced that the adsorption followed the pseudo-second-order rate equation and Langmuir isotherm models. The maximum adsorption capacities were found to be 1109.55 and 1081.60 mg/g for CMC-cl-pAA hydrogel and CMC-cl-pAA/Fe₃O₄-C30B hydrogel nanocomposite, respectively. The adsorption thermodynamic studies suggested that the adsorption process was spontaneous and endothermic for CMC-cl-pAA/Fe₃O₄-C30B hydrogel nanocomposite. The homogeneous dispersion of the Fe₃O₄-C30B nanocomposite in the CMC-cl-pAA hydrogel significantly improved the thermal stability, mechanical strength, and excellent regeneration stability. This study demonstrates the application potential of the fascinating properties of CMC-cl-pAA/Fe₃O₄-C30B hydrogel nanocomposite as a highly efficient adsorbent in the removal of organic dyes from aqueous solution.

Parabens, triclosan, and lipid regulators are frequently used in pharmaceuticals, personal care, hygiene, food, and other products. The final destination of these compounds frequently is domestic sewage. In many cases, collection and treatment systems are not completely efficient, and these compounds reach the environment. However, many of these substances are toxic, and their presence poses risks to several organisms. This study has the goal to determine the occurrence of five personal care products and two lipid regulators in three rivers in southern Brazil. Four sampling campaigns were conducted in December, March, June, and October in three rivers. Risk assessment was performed, and the general index of human contamination (GIHC) was used to evaluate water pollution in the area. Compounds were analyzed using an Agilent GC-MS/MS 7890A chromatograph. The monitoring and reaction mode (MRM) was employed for the detection and quantification of the compounds. Gemfibrozil was detected in concentrations up to 2590 ng L⁻¹ and personal care products up to 788 ng L⁻¹. Fenofibrate was not detected in any sample, while gemfibrozil, methylparaben, propylparaben, and triclosan were detected in all samples. Risk assessment indicated that triclosan, propylparaben, and gemfibrozil should be designated as priority compounds in the area. GIHC is a simple and efficient tool to assess pollution in urban areas and can be employed in future studies. The results indicated that areas upstream of the WWTPs had higher contamination levels than downstream, indicating that diffuse pollution and illegal effluent discharges may have a strong influence on the water quality in the area.

Although the number of cholera infection decreased universally, climate change can potentially affect both incidence and prevalence rates of disease in endemic regions. There is considerable consistent evidence, explaining the associations between cholera and climatic variables. However, it is essentially required to compare and interpret these relationships globally. The aim of the present study was to carry out a systematic review in order to identify and appraise the literature concerning the relationship between nonanthropogenic climatic variabilities such as extreme weather- and ocean-related variables and cholera infection rates. The systematic literature review of studies was conducted by using determined search terms via four major electronic databases (PubMed, Web of Science, Embase, and Scopus) according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) approach. This search focused on published articles in English-language up to December 31, 2018. A total of 43 full-text studies that met our criteria have been identified and included in our analysis. The reviewed studies demonstrated that cholera incidence is highly attributed to climatic variables, especially rainfall, temperature, sea surface temperature (SST) and El Niño Southern Oscillation (ENSO). The association between cholera incidence and climatic variables has been investigated by a variety of data analysis methodologies, most commonly time series analysis, generalized linear model (GLM), regression analysis, and spatial/GIS. The results of this study assist the policy-makers who provide the efforts for planning and prevention actions in the face of changing global climatic variables.

The sediment acts as not only sink but also source of heavy metals in aquatic environment, which may cause the endogenous pollution in drinking water reservoirs. In this work, we collected the surface sediments from Qingcaosha Reservoir, the largest river-embedded reservoir in China, and investigated the spatial distribution, risk, and sources of heavy metals in four seasons. Significant spatial and seasonal heterogeneity could be found in the distribution of five heavy metals (Cr, Cu, Mn, Zn, and Ni) in the surface sediments. The highest concentrations of the five metals were detected in the sediments from the reservoir downstream, especially in summer and next spring. The geo-accumulation index (Igₑₒ) and enrichment factor (EF) suggest that the sediment pollution caused by single metal was heavier in summer than in other seasons. Also, the Nemerow pollution index (PIN) manifests that the synergetic pollution induced by five metals was most serious in summer, followed by next spring. However, the potential ecological risk index (PERI) indicates that none of these metals caused potential ecological risk in four seasons. Comprehensive analysis demonstrates that the sediment pollution gradually increased from autumn to winter and then to next spring. Principal component analysis shows that the main pollution source of five heavy metals may come from industrial wastewater and domestic sewage, which was almost independent of seasons. This work can provide data support for the subsequent seasonal optimization of drinking water quality and reservoir management.

A total of 77 street dust samples were collected from Jinan City in East China and were analyzed for the concentrations, speciation, bioavailability, and influencing factors of ten heavy metals. The results showed that the average concentrations of Ba, Co, Cr, Cu, Cd, Mn, Ni, Pb, Zn, and V in the street dust were 642.77, 8.24, 114.09, 87.71, 1.08, 517.04, 30.29, 80.32, 497.84, and 51.76 mg/kg, and the concentrations of Ba, Cr, Cu, Cd, Ni, Pb, and Zn exceeded the local soil element background values. In the street dust, Ba, Co, Cr, Mn, Ni, and V were mainly in the residual; Cu and Pb were controlled by the oxidizable; Cd mainly existed in the acid extractable; and Zn was dominated by the reducible. According to the ratios of the acid extractable to the sum of four forms, Cd (39.85%) presented a high environmental risk; Mn and Zn (24.29% and 27.78%) exhibited a medium risk; and V, Cu, Pb, Ba, Co, Ni, and Cr had no environmental risk. The order of mobility or potential risk of heavy metals was Cd (85.8%) > Zn (77.1%) > Cu (64.3%) > Pb (62.0%) > Mn (51.7%) > Ba (38.9%) > Co (31.2%) > Ni (30.1%) > V (25.8%) > Cr (23.1%), suggesting that Cd, Zn, Cu, Pb, and Mn presented relatively high movability and risk. The bioavailability order of heavy metals was Cd (82.7%) > Zn (63.6%) > Mn (40.4%) > Ni (20.4%) > Pb (11.7%) > Cu (11.1%) > V (7.8%) > Cr (3.7%) in the gastric phase and Cu (24.6%) > Cd (19.9%) > Mn (16.2%) > Ni (6.6%) > Pb (5.7%) > Zn (4.4%) > Cr (3.0%) > V (2.3%) in intestinal phase, implying that Cd, Zn, Mn, and Cu were highly bioavailable in the gastrointestinal environment, which coincided with the risk of speciation. The speciation of heavy metals in street dust had certain correlations with their bioavailability. The physiochemical properties of street dust had significant effects on the concentrations, speciation, and bioavailability of heavy metals in street dust. The simple, fast, and nondestructive magnetic measurements could be used as indicators of the concentrations, speciation, and bioavailability of heavy metals in street dust.

In this study, the dispersion stability and reactivity of sulfide-modified nanoscale zerovalent iron (SNZVI) coated with different surface stabilizers (i.e., starch, sodium dodecylbenzene sulfonate (SDBS), or carboxymethyl cellulose (CMC)) were investigated. All the three types of surface stabilizers could enhance the dispersion stability of SNZVI but exerted differing influences on the reactivity toward trichloroethylene (TCE) removal. The coating of starch on SNZVI markedly improved TCE removal, which was positively correlated with the enhanced dispersion stability (i.e., more active surface sites). However, although the SDBS and CMC could enhance the dispersion stability of SNZVI, they resulted in an inhibition in TCE removal, especially for CMC. It was presumed that the coated SDBS/CMC on the surface of SNZVI occupied the active surface sites for TCE removal. Besides, the effect of groundwater geochemistry (i.e., pH, Ca²⁺, and humic acid (HA)) was examined. The increasing pH from 5 to 9 led to a slight decrease for all stabilized SNZVI particles. The presence of Ca²⁺ or HA exerted distinct influence on the TCE removal by the three stabilized SNZVI. The Ca²⁺/HA exerted an insignificant effect on the reactivity of CMC-SNZVI but markedly decreased the reactivity of starch-SNZVI and SDBS-SNZVI. The varying effects of Ca²⁺/HA should be due to their distinct interactions with different types of stabilizers on the surface of SNZVI.

In the context of the rapid development of the Belt and Road (B&R) Initiative, the continuous transfer of Sino-US trade to the B&R countries is an important means to mitigate the threat of Sino-US trade, and the environmental impact of this transfer should be considered, so as to provide a scientific basis for China’s policy formulation about achieving this possible trade transfer with minimized environmental impacts. This study proposes a multiregional input-output model and analyzes the impact on carbon dioxide (CO₂) emissions of transferring the Sino-US trade to the B&R countries for two types of scenarios. The results show the following: (1) A transfer of either the import trade or the export trade increases global and Chinese CO₂ emissions by 81.76 Mt and 24.84 Mt, respectively. When both the import trade and export trade are transferred, the increases in CO₂ emissions are only 0.22% and 0.26%, respectively. (2) Globally, the changes in international trade-embodied CO₂ emissions are responsible for most of the global emission changes, especially the CO₂ emissions exported from Russia, India, and many Southeast Asian countries to China. (3) Different from the impact on global emissions, the increases in Chinese domestic production-based CO₂ emissions influence China’s total CO₂ emissions. Due to the imported CO₂ emissions, the consumption-based CO₂ emissions are affected to a greater degree and increase by 70.30 Mt, accounting for only 0.86% of the CO₂ emissions in 2015. Finally, some policy implications are proposed.

Green vegetation improvement is an economical strategy to mitigate dust air pollution. The anticipated performance index (API) is considered a main criterion to select the suitable plants of urban forests. API is calculated by taking air pollution tolerance index (APTI) and socio-economic and biological aspects into account. In the present work, API of four current deciduous tree species in urban areas of Iran was evaluated. The seedlings were soil-dusted by a dust simulator in plastic chambers at levels of 0, 300, 750, and 1500 μg/m³ at intervals of 1 week for 70 days. At 750 and 1500 μg/m³ dust concentrations (DCs), greatest dust collection capacity was observed with Morus alba and the lowest one with Melia azedarach. Increasing DC declined APTI of all species. At 750 μg/m³ DC, only Morus was tolerant, but at 1500 μg/m³ DC, this species and Melia were categorized as intermediate, and Celtis caucasica and Fraxinus rotundifolia as sensitive. Morus was assessed as a good performer under two higher DC. Celtis was recognized as a moderate under 750 μg/m³ DC and poor performer under 1500 μg/m³ DC. Thus, Celtis can be considered as a biomonitor for air quality or as sink for dust in high dusty areas because of its high capacity of dust deposition. At two higher DCs, Fraxinus and Melia showed very poor and poor performance; planting these species in high dust areas is not recommended. In contrast, Morus is the most suitable tree species for urban green spaces in dusty regions, due to its high dust collection capacity and high APTI and API values.

Previous studies have indicated that particulate matter 2.5 (PM2.5) exposure stimulates systemic inflammation and activates the hypothalamus–pituitary–adrenal (HPA) axis, both of which are associated with stroke incidence and mortality. However, whether filtered air (FA) intervention modulates inflammation and HPA axis activation is still largely unknown. For FA group and PM2.5 group, adult Sprague-Dawley male and female rats were exposed to FA or PM2.5 for 6 months, respectively. For PM2.5 + 15 days FA group, the rats were achieved by receiving 15 days FA after PM2.5 exposure for 6 months. The immune cells and inflammatory biomarker levels in the blood and brain were analyzed by flow cytometry, ELISA, and qRT-PCR. To assess HPA axis activation, the levels of hormones in the blood were also analyzed by ELISA. FA intervention increased the percentage of CD4 T cells and T cells in the blood, which had decreased after PM2.5 exposure in both male and female rats. The ELISA and qRT-PCR results showed that FA intervention significantly reduced the levels of inflammatory biomarkers in the peripheral blood, and alleviated neuroinflammation in the cortex, hippocampus, and striatum. In addition, FA intervention also inhibited the inflammation in the hypothalamus and pituitary and adrenal glands, and decreased the levels of HPA axis hormones. Our results indicate that FA intervention exerts a protective effect on the brain by decreasing inflammation and HPA axis activation after PM2.5 exposure in both male and female rats.

Environmental objects (surface and groundwater, soil, bottom sediments, wastewater) are reservoirs in which large-scale multidirectional exchange of determinants of antibiotic resistance between clinical strains and natural bacteria takes place. The review discusses the results of studies on antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARG) isolated from environmental objects (water, soil, sewage, permafrost) of the Russian Federation. Despite the relevance of the topic, the number of available publications examining the resistomes of Russian water bodies and soils is small. The most studied environmental objects are surface waters (rivers, lakes), permafrost deposits. Soil resistomes are less studied. Data on ARG and ARB in wastewater are the least covered in publications. In most of the studies, antibiotic resistance of isolated pure bacterial cultures was determined phenotypically. A significant number of publications are devoted to the resistance of natural isolates of Vibrio cholerae, since the lower reaches of the Volga and Don rivers are endemic to cholera. Molecular genetic methods were used in a small number of studies. Geographically, the south of the European part of Russia is the most studied. There are also publications on the distribution of ARG in water bodies of Siberia and the Russian Far East. There are practically no publications on such developed regions of Russia as the center and northwest of the European part of Russia. The territory of the country is very large, anthropogenic and natural factors in its various regions vary significantly; therefore, it seems interesting to combine all available data in one work.