Environmental Science and Pollution Research最新文献

The middle and lower reaches of the Jinsha River, which is the upper reach of the Yangtze River in China, play crucial roles in the water security of people living in the middle and lower reaches of the Yangtze River. The construction of 11 dams in this region has significantly altered the aquatic environment. Although researchers have investigated the effects of cascade hydropower station development in the middle and lower reaches of the Jinsha River based on factors such as flow, sediment, and fish, the overall impact of this station on the aquatic environment remains unclear. Therefore, the purpose of this study is to comprehensively investigate the effects of cascade hydropower station development on the aquatic environment based on three factors: river, aquatic organism, and ecosystem factors. In terms of river factors, the development of cascade hydropower stations increases runoff in the dry season and decreases it in the flood season, leading to sediment deposition and water temperature stratification in cascade reservoirs, and changes in water quality. In terms of aquatic organism factors, cascade hydropower development not only changes the species composition but also reduces biodiversity. Effects of ecosystem factors including the ecological flow, value, and landscape as well as sustainability are summarized, with results indicating positive and negative impacts on river ecosystems. Finally, recommendations for future research on the effects of cascade hydropower development on the aquatic environment of rivers are provided.

China is currently in a new era of an urban transition to a low-carbon economy and digital economic development. Smart cities, as an advanced form of information-based urban development, may be the key to the urban transition to low-carbon emissions. This paper examined the effect of smart city construction (SCC) on urban low-carbon transitions and its transmission mechanisms in China from the dual perspectives of reducing urban total carbon emissions (TCE) and improving urban total-factor carbon emission efficiency (TFCEE). Utilizing a multi-period difference in differences (DID) method, this study was conducted based on panel data of 245 Chinese prefecture-level cities from 2003 to 2021. The results demonstrated that SCC both reduced TCE and enhanced TFCEE. The effects of SCC were stronger in cities with more stringent environmental regulations. SCC achieved the dual effect of reducing TCE and enhancing urban TFCEE by promoting green technological progress and a low-carbon transformation of city residents' lifestyles. Moreover, optimization of the industrial structure was also a transmission mechanism for SCC to improve TFCEE. These conclusions provide an empirical basis for the SCC to empower low-carbon transitions of cities and help countries in different regions to transform the extensive urban development mode and promote urban low-carbon economic development.

The present study aims to assess agricultural vulnerability in the context of climate change, focusing on the diverse districts of Odisha. Acknowledging that vulnerability is influenced by exposure, sensitivity, and adaptive capacity, our research incorporates the growth rate and instability of vital performance indicators to evaluate the relative vulnerability of each district. A key strength of this approach is the use of normalized indicators, weighted in accordance with the proportional acreage of major crops in each district relative to the state, culminating in a comprehensive vulnerability index through the aggregation of these weighted components. Our findings reveal significant variability in the vulnerability profiles across districts, thereby necessitating state-level intervention through tailored "Location Performance Vulnerability" based adaptation strategies. These strategies, including early weather warning systems, development of new and early maturing crop varieties, and adjustment of crop planting dates, are crucial for mitigating the adverse effects of climate change on agriculture. The study's methodology and findings offer significant contributions to the field, providing policymakers and stakeholders with a district-specific framework for climate change adaptation. This approach is especially relevant for the international academic and policy-making communities, as it highlights the importance of localized adaptation strategies in the broader context of global climate change resilience.

Ozone-based advanced oxidation processes (AOPs) have emerged a promising avenue for water treatment, offering effective removal of micropollutants. Recent research underscores the potential of ozone microbubbles to enhance ozone mass transfer during water treatment, particularly when combined with pre-treatment steps. This study aimed to evaluate the efficacy of three different combined processes (chlorine/KMnO₄/PAC pre-treatment followed by ozonation) in removing atrazine, a common micropollutant from natural source water. Results revealed that all combined processes achieved higher atrazine removal rates compared to individual pre-treatment or ozonation methods. Notably, the highest atrazine removal rates were observed under alkaline pH conditions, with treatment outcomes influenced by oxidant dose and pH levels. Among the combined processes, chlorine pre-treatment followed by ozonation emerged as the most effective approach, achieving a removal rate of 59.7% that exceeded the sum of individual treatments. However, this treatment efficacy was affected by water quality parameters, particularly the presence of organic matter and elevated ammonia nitrogen concentration (> 0.5 mg/L). This study highlights the potential for utilizing ozone micro/nanobubbles to enhance ozone mass transfer and offers valuable insights for optimizing the combined application of pre-treatment and ozonation strategies for efficient atrazine removal from natural water sources.

Sixteen PAHs in ambient air samples collected from residential and roadside areas in the Hanoi metropolitan were investigated. Total PAH concentrations in the ambient air samples ranged from 45.0 to 451 ng/m³. Among PAHs, phenanthrene was found at the most abundant and highest levels. The distributions of PAHs in the ambient air collected in the dry season were on average 26% higher than in the wet season. The PAH concentrations in the air samples collected from the traffic areas were significantly higher (about 2.7 times) than those in the residential areas, indicating that these chemicals originated from motor vehicles. According to vertical, the PAH concentrations found in the ambient air samples collected from the ground floor were significantly higher than on the upper level, however, there was not much difference when going higher (from 24 m (8th floor) to 111 m (37th floor)). The human exposure doses were estimated for two age groups (adults and children) based on the measured PAH concentrations, the inhalation rates, and body weights. The estimated exposure doses to PAHs through inhalation for adults/children were 1.13/2.86 (ng/kg-bw/d) (residential areas) and 3.24/8.18 (ng/kg-bw/d) (traffic areas), respectively. The average lifetime excess cancer risk (ECR) from inhalation exposure to PAHs was 3.0 × 10^-4 at the traffic areas and 1.4 × 10^-4 at the residential areas. These estimated exposure doses were above the acceptable level of the California Environmental Protection Agency (CalEPA) Office of Environmental Health Hazard Assessment (1*10^-6).

The study of the adsorption of polycyclic aromatic hydrocarbons on microplastics (MPs) has attracted much attention as to how microplastics can act as carriers of these pollutants. Polyurethane (PU) is one of the MPs found in aquatic environments, containing different functional groups it can interact with polar and nonpolar molecules. PAH derivatives (dPAHs) present different properties and thus can be adsorbed by different interactions; thus, this study investigated the adsorption of fluorene (FLN), dibenzothiophene (DBT), dibenzofuran (DBF), and carbazole (CBZ) onto PU MP. The Langmuir, Freundlich, and BET isotherm models were examined, and the BET model best fitted. The adsorption was a nonspontaneous process, exothermic for mono- and multilayer formation for FLN, DBT, and CBZ, and endothermic for DBF monolayer formation. The adsorption monolayer was formed by van der Waals forces, H─bonding, and π─π interactions, while the formation of the multilayer can be explained by π─π and hydrophobic interactions. The pseudo-second-order model proved to be more consistent for the adsorption of dPAHs. The adsorption in artificial seawater shows no significant differences for the monolayer but favored the adsorption multilayer due to the salting-out effect. Due to the existence of several adsorption mechanisms, PU MP interacts with dPAHs in greater quantities when compared to a MP with a simpler structure.

Lithium (Li) exploitation promotes socioeconomic advances but may result in harmful environmental impacts. Thus, species selection for recovering environments degraded by Li mining is essential. We investigated the tolerance and early growth of four tree species to Li ore tailings (LOT), Enterolobium contortisiliquum and Handroanthus impetiginosus with wide geographic distribution and Hymenaea courbaril and H. stigonocarpa with restricted geographic distribution. The plants grew in LOT and soil for 255 days to evaluate photosynthesis, growth, and mineral nutrition. LOT negatively affected species growth, reducing the length of stems, roots, and biomass through structural and nutritional impoverishment. LOT favored the accumulation of Mg and decreased the absorption of K. The species presented a reduction in potential quantum efficiency and the chlorophyll index (b and total). E. contortisiliquum was the least tolerant species to LOT, and H. courbaril and H. stigonocarpa maintained their mass production in LOT, indicating greater tolerance to tailings. Furthermore, H. courbaril presented a translocation factor > 1 for Li and Mn, indicating the potential for phytoextraction of these metals. Our results offer first-time insights into the impacts of LOT on the early development of tree species with different geographic distribution ranges. This study may help in the tree species selection with a phytoremediation role, aiming at the recovery of areas affected by Li's mining activity.

A magnetic hydrogel based on xylan (X), poly (acrylic acid), and maghemite (γ-Fe₂O₃) named HXA-Fe₂O₃ was synthesized, characterized, and applied as an alternative material to remove methylene blue (MB) from aqueous media by adsorption. Maghemite was synthesized by coprecipitation method and later incorporated in the hydrogel matrix synthesized by free radical polymerization. The characterization studies included FTIR, DSC, XRD, VSM, Zeta Potential, TGA, SEM, TEM, and N₂ adsorption isotherms (BET). The physicochemical characterization results confirmed the intended synthesis and showed the compositional, thermal, structural, morphological, textural, and magnetic profile of the materials. The adsorption studies included experimental design, kinetic, and isotherm. A full factorial design was employed considering the factors adsorbent dosage (g L^-1), pH, and ionic strength (mmol L^-1 of NaCl) for adsorption capacity and removal percentage responses. As ionic strength was not significant, a Doehlert design was employed with adsorbent dosage and pH, indicating the optimal adsorption conditions. The kinetics was well described by the PSO model, while the isotherm obeyed the Sips model. Equilibrium was attained at 60 min, and the maximum experimental adsorption capacity was up to 250.26 mg g^-1 at pH 8.5, adsorbent dosage of 0.2 g L^-1, and 298 K. These findings show that the magnetic hydrogel produced has great potential to be applied in the adsorption of basic molecules, such as MB.

Tingui biochar (TB) activated with potassium hydroxide (TB-KOH) was synthesized in the present study. The adsorption capacity of TB-KOH was evaluated for the removal of acetaminophen and caffeine in monocomponent and bicomponent solutions. As a result, the study of the TB-KOH characterization as well as the adsorption kinetics, isotherm, thermodynamics, and a suggestion of the global adsorption mechanism are presented. TB-KOH was characterized through physical-chemical analysis to understand its surface morphology and how it contributes to the adsorption of these drugs. Furthermore, modelling using advanced statistical physical models was performed to describe how acetaminophen and caffeine molecules are adsorbed in the active sites of TB-KOH. Through the characterizations, it was observed that the activation with KOH contributed to the development of porosity and functional groups (-OH, C-O, and C = O) on the surface of TB. The monocomponent adsorption equilibrium was reached in 90 min with a maximum adsorption capacity of 424.7 and 350.8 mg g^-1 for acetaminophen and caffeine, respectively. For the bicomponent solution adsorption, the maximum adsorption capacity was 199.4 and 297.5 mg g^-1 for acetaminophen and caffeine, respectively. The isotherm data was best fitted to the Sips model, and the thermodynamic study indicated that acetaminophen removal was endothermic, while caffeine removal was exothermic. The mechanism of adsorption of acetaminophen and caffeine by TB-KOH was described by the involvement of hydrogen bonds and π-π interactions between the surface of TB-KOH and the molecules of the contaminants.

Nano-biocomposite hydrogel samples were produced using graphene oxide (GO) and agar and applied as adsorbents of organic components in water. The hydrogels were prepared by varying the wt% of Agar and GO. The samples were characterized, and batch adsorption experiments evaluated the effect of initial pH, equilibrium isotherms, and kinetics for the adsorption of the anionic dye Acid Orange 7 (AO) and the cationic dyes Nile Blue A (NB) and methylene blue (MB) in an aqueous medium. Overall, both hydrogel samples exhibited satisfactory results for removing NB and MB; however, there was no effective removal for the anionic dye AO. Adsorption equilibrium isotherms were obtained, and Freundlich, Langmuir, and Sips models were fitted to the experimental equilibrium data; moreover, kinetic data were adjusted to driving force models and particle mass balance. The maximum experimental adsorption capacities, 141.48 mg·g^-1 (MB) and 284.69 mg·g^-1 (NB), were obtained, on a dry basis, for the sample produced with 70 wt% of agar and 30 wt% of GO. Both hydrogels exhibited remarkable regenerative potential for NB and MB, with the adsorption capacity remaining constant, even after five adsorption/desorption cycles.