Environmental Science and Pollution Research最新文献

In fluvial environments, the shifting of river channels and bank erosion are frequently caused by both natural and anthropogenic factors. Riverine hazards like bank erosion and course alterations offer severe issues to the riparian villages along the lower basin of the Tista River in India, which substantially influence the livelihoods of inhabitants living there. This research addressed river channel shifting tendency and identified major bank erosion-prone villages along the lower course of the Tista River and challenges to the livelihoods of the riparian people. Along with these, land use and land cover changes of the riparian villages since 1993-2023 have been assessed with accuracy testing based on the Kappa coefficient. The results of this study observed that on the right bank of the Tista River, migration is occurring at a rapid pace. Due to the consequences of numerous riverine hazards, the demographic profile of the riparian villages (viz., Case Study-I: Domohani village in Jalpaiguri District) exhibited a negative tendency in the rate of population growth. The study of the riparian villages' changes in land use and cover reveals a 20% decrease in vegetation cover, and both sandbars and water bodies witnessed a declining quantity. The household survey was conducted based on Cochran's method (1963); acquired results demonstrated that floods, bank erosion, and the Tista River's channel shifting behavior negatively impacted the majority (more than 80 percent) of the inhabitant's income. The continuous erosion threatens the stability of the riparian villages; by acknowledging these hazards and implementing appropriate measures, riparian villages can enhance their resilience, protect their livelihoods, and ensure the well-being of their communities in the face of these natural threats.

Climate change significantly impacts the risk of eutrophication and, consequently, chlorophyll-a (Chl-a) concentrations. Understanding the impact of water flows is a crucial first step in developing insights into future patterns of change and associated risks. In this study, the Statistical DownScaling Model (SDSM)-a widely used daily downscaling method-is implemented to produce downscaled local climate variables, which serve as input for simulating future hydro-climate conditions using a hydrological model. The vulnerability of water quality, particularly Chl-a concentrations in the Latyan Dam and Tehranpars Water Treatment Plant (TWTP) is assessed through six fuzzy regression models under three scenarios: RCP2.6, RCP4.5, and RCP8.5. Projections indicate an increase in minimum temperatures for the Jajrood watershed ranging from 92 to 93%. Seasonal forecasts suggest significant precipitation during the dry season. The HYMOD model predicts increases in streamflow of approximately 97%, 90%, and 92% by 2050 under RCP2.6, RCP4.5, and RCP8.5, respectively, indicating a heightened risk of flooding that poses economic, health, and environmental concerns. Among the six fuzzy regression models, FGR1, FGR3, and FGR4 demonstrated the most favorable results in modeling Chl-a output from the TWTP. In conclusion, while Chl-a concentrations in the effluent of the TWTP are only slightly influenced by climate change, the effects on streamflow patterns are significant. These findings highlight serious future water quality challenges and increased vulnerability of water resources due to climate change.

Sustainable pavement is essential for country development, offering durable, environmentally friendly, and cost-effective infrastructure. For Malaysia, sustainable pavement supports Sustainable Development Goals (SDGs) 9 and 11 while addressing road deterioration caused by increasing traffic volumes and loads. This deterioration shortens pavement service life and necessitates frequent maintenance, driving the need for innovative solutions. To enhance pavement sustainability, researchers have explored additives like plastic waste, specifically low-density polyethylene (LDPE), a major component of packaging waste. LDPE improves durability but is prone to fatigue cracking. Addressing this, physical treatments of LDPE can improve its surface topography, compaction properties, and binder-aggregate adhesion, optimizing pavement performance. This study evaluated hot mix asphalt mixtures incorporating untreated plastic (UP) and treated plastic (TP) additives under varied compaction efforts and mixing temperatures. Performance tests, including Marshall stability, resilient modulus, creep, and tensile strength ratio (TSR), were conducted. Results showed that the TP50L mixture (with 25% fewer compaction blows and a mixing temperature reduced by 25 °C) performed better than the UP and control mixtures, demonstrating 30% greater fatigue resistance, 11% higher rutting resistance, and 12% improved moisture damage performance. The superior performance of TP additives is attributed to their rougher surface, enhancing the binder-aggregate bond and aggregate properties. The study concludes that treated plastic additives not only strengthen pavements against permanent deformation but also reduce compaction efforts and mixing temperatures, leading to lower energy use during construction. By incorporating plastic waste into pavements, this approach promotes environmental sustainability, reduces maintenance needs, and supports eco-friendly infrastructure development.

The aim of the present work is to investigate the photocatalytic degradation of propyl paraben (propyl para-hydroxybenzoate, PrP) using Cu₂O-ZnO-NPs photocatalyst followed by the identification of the oxidation by-products. The Cu₂O-ZnO-NPs material, synthesized using a green chemistry approach, was used as a photocatalyst for the removal of PrP. The nanoparticles were characterized by XRD, XRF, diffuse reflectance spectroscopy, ATG/DTG, FTIR, SEM-EDX, BET and FRX techniques. The XRD results showed that Cu₂O-ZnO-NPs have a nanometer size of 24.13 nm. The DR-UV analysis showed that Cu₂O-ZnO-NPs has an E_g of 2.35 eV which corresponds to the absorption of visible light. The SEM-EDX analysis showed that the ZnO has a hexagonal structure while the CuO has a monoclinic structure. The effect of variables such as propyl paraben concentration (PrP), hydrogen peroxide concentration (H₂O₂), catalyst dose, and the reaction temperature on the pseudo-first order reaction rate constant (k_app) of the reaction was evaluated. It was found that the degradation of PrP was governed by hydroxyl radical °OH attack and the pathways consisted of a cascade of reactions. The optimum photocatalytic degradation was obtained with an initial catalyst dose of 50 mg, pH 7, and PrP concentration of 10 mg/L. When the photocatalyst was irradiated, a significant PrP degradation was observed after 30 min of irradiation. The results suggest that Cu₂O-ZnO-NPs act as a good photocatalyst for PrP degradation under visible light.

Decoupling economic growth and carbon emissions is essential to a sustainable high-quality development. As a small unit of the engine of development, more research has begun to focus on city-level issues. In order to fill the gaps in the decoupling research at the city level covering the whole nationwide, this paper applied the bottom-up method to calculate 282 cities' carbon emissions according to China's city-level panel data of terminal energy consumption, and combined Tapio decoupling with LMDI decomposition model to analyze cities' decoupling status and its driving factors. The results reflect that (1) strong decoupling, weak decoupling, expansive coupling, and expansive negative decoupling were the main decoupling states of Chinese cities and the strong decoupling cities were mainly clustered in the southwestern area. (2) The COE effect, ES effect, and EI effect were negative in most cities, promoting the realization of strong decoupling in most cities, but the contribution of COE effect and ES effect to the decoupling effect was relatively small. (3) The nature differences of ES effect and EI effect were the crucial reason for the significant differences in the degree of decoupling among different types of cities, especially the differences of EI effect in both SD cities and WD cities during 2005 to 2010 and 2010 to 2015. Based on the findings, some common but differentiated recommendations are provided for promoting the decarbonization of the economy in Chinese cities.

The COVID-19 pandemic and subsequent lockdown measures significantly impacted various sectors, including coastal environments. While restrictions led to temporary improvements in air quality, their effects on coastal waters remained understudy. This research conducted four cruises along the east coast of India during pre- and post-COVID-19 lockdown to assess the water quality changes. Results show a significant increase in Chl-a (31.8%), DO (28.1%), and SDD (7.7%), while reductions in NO₃ (34.7%), PO₄ (51.7%), SiO₄ (16.2%), TSM (25.4%), TC (72.3%), and FC (83.3%) were observed. Multivariate analysis identified land-based pollution as the primary source of pollution in coastal waters. Overall, the findings suggest improved coastal water quality during the lockdown. However, for the sustainability of coastal waters, it is proposed that raw sewage, wastewater, and atmospheric fluxes affecting coastal water quality must be regulated.

Climate change, driven by carbon emissions, has emerged as a pressing global ecological and environmental challenge. Here, we leverage the panel data of five provinces and above prefecture-level cities in the middle and lower reaches of the Yellow River Basin to estimate the agricultural carbon emissions (CEs), carbon sinks (CSs), carbon compensation rate (CCR), and carbon compensation potential (CCP) from 2001 to 2022 and investigate the spatiotemporal evolution characteristics for this region. We propose an improved GLM-stacking ensemble learning method for CE prediction with limited sample data. The findings indicate the following: (i) From 2001 to 2022, the overall CEs show a trend of "development - decline - stabilization" and reach a peak of 172.54 Mt in 2005. CCR first exceeded the "CCR = 1" in 2008, which also indicates that reducing CEs and increasing CSs are the paths to achieving agricultural carbon neutrality. (ii) Although each province has achieved "net-zero emissions," the CCP of most urban agglomerations is about 0.5 and shows a certain agglomeration trend, indicating significant room for further carbon offset. (iii) The novel GLM-stacking model has higher prediction accuracy when compared to a single model. These findings provide scientific and technological support to realize the provincial dual carbon goals in China.

Fluorescent lifetimes of dissolved organic matter (DOM) and associated physicochemical parameters were measured over 14 months in an estuary in Southern California, USA. Measurements were made on 77 samples from sites near the inlet, mid-estuary, and outlet to maximize the range of physicochemical variables. Time-resolved fluorescence data were well fit to a triexponential model with an intermediate lifetime component (τ₁: 1 to 5 ns), a long lifetime component (τ₂: 2 to 15 ns), and a short lifetime component (τ₃: < 1 ns). The amplitude of the short-lived component dominated all measurements (60-70%). However, fractional contributions to steady-state fluorescence were dominated by the intermediate and long-lived components at most wavelengths. Lifetimes varied as a function of both excitation and emission wavelength suggesting structural differences in DOM fluorophores. Lifetimes decreased from the estuary inlet to the outlet and were positively correlated with absorbance and DOC concentrations and negatively correlated with salinity and spectral slope. Quenching experiments with halide ions demonstrated that fluorophores are quenched by heavy ions and that different fluorophores are quenched at different rates. However, concentrations of ions in seawater are not high enough for quenching to completely account for observed lifetime changes across the estuary. The observed variation in lifetimes between sites is instead primarily attributed to structural changes associated with DOM processing. Higher lifetimes are associated with less processed material at the inlet site.

The production of nitrogen oxides (NO $_{\text{x}}^{}$ = NO + NO $_2^{}$ ) is substantial in urban areas and from fossil fuel-fired power plants, causing both local and regional pollution, with severe consequences for human health. To estimate their emissions and implement air quality policies, authorities often rely on reported emission inventories. The island of Cyprus is de facto divided into two different political entities, and as a result, such emissions inventories are not systematically available for the whole island. We map NO $_{\text{x}}^{}$ emissions in Cyprus for two 6-month periods in 2021 and 2022 with a flux-divergence scheme, using spaceborne retrievals of nitrogen dioxide (NO $_2^{}$ ) columns at high spatial resolution from the TROPOMI instrument, as well as horizontal wind data to derive advection and concentrations of OH, NO, and NO $_2^{}$ to derive chemical processes. Emissions are estimated under three different sets of parameters using ECMWF data and WRF-Chem simulations. These sets are chosen for their differences in spatial resolution and representation of wind and air composition. Exploiting the low emissions in Cyprus, we show that the flux-divergence method is limited by the resolution of wind and hydroxyl radical, the signal-to-noise ratio of the observed tropospheric column densities, and the NO $_{\text{x}}^{}$ :NO $_2^{}$ ratio above the main pollution sources. Such limitations lead to large discrepancies in the emissions calculated with the three different sets of parameters, making it difficult to estimate NO $_{\text{x}}^{}$ emissions for the five power plants of the island without high uncertainties. Nevertheless, the obtained emissions display a higher seasonality than reported or inventory emissions. For the two power plants in the south, the different mean daytime output estimates appear to be significantly higher than the bottom-up estimates. They are also higher than those from the power plants in the south combined, despite a much lower production capacity, illustrating the application of different environmental norms and the use of different technologies and fuels in the two parts of Cyprus.

Liquid low-level radioactive waste at the Savannah River Site contains several species of mercury, including inorganic, elemental, and methylmercury. This waste is solidified and stabilized in a cementitious waste form referred to as saltstone. Soluble mercury is stabilized as β-cinnabar, HgS as the result of reaction between the mercury and sulfur present in blast furnace slag, one of the cementitious reagents. In this investigation, Mersorb®, a commercial granular activated carbon impregnated with sulfur, was evaluated as a pretreatment to remove mercury from the solution prior to cementation. Mersorb® was found to remove more than 96 mass percent of the methylmercury in simulated tank waste solution when the mass ratio of Mersorb® to mercury was above 2.5. Slag sequestered relatively more inorganic mercury than organic mercury in simulated tank waste after 24 h of contact. This is likely due to the mercury-carbon bond being more covalent than the mercury-oxygen bond and therefore more difficult to break and slower to form HgS.