International Journal of Environmental Research最新文献

Climate change has a potentially negative impact on the overall vitality of vegetation in both forested and agricultural areas. A comprehensive understanding of the interaction between climate and vegetation across various land cover types holds significant importance from multiple perspectives. This research examined the current state of vegetation trends and their interplay with climate parameters, specifically temperature and precipitation. Additionally, it aimed to provide insights into the anticipated changes in these climate parameters in the future, across the entire area of the Republic of Serbia. The vegetation was observed using the Normalized Difference Vegetation Index (NDVI) obtained from AVHRR/NOAA 11 satellite for the vegetation season (May–October) from 1981 to 2021, while the climate data records used the examination of the relationship between climate indicators and vegetation were monthly mean 2m temperature and precipitation obtained from the ERA5-Land (from April to October). The nonparametric Mann–Kendall test implemented with the Sen's slope estimator and the Pearson correlation coefficient (r) was utilized to identify trends (for the NDVI and climate variables) and the strength of the correlation, respectively. To obtain the information of temperature and precipitation change in future (from 2071 to 2100), the ensemble mean of the eight climate models, for vegetation period and summer season (June–July–August) from the EURO-CORDEX database was used. Results show relatively high NDVI values (> 0.5) over the entire area and the statistically significant (p < 0.005) positive NDVI trend increasing (up to 0.0006 ({text{year}}^{-1}))from the north (mainly agriculture cover) to the south (forest cover). In agricultural areas, a positive statistically significant correlation (r = 0.4–0.6, p < 0.005) indicates that the quality of vegetation cover in rainfed agriculture is directly dependent on the amount of precipitation, which serves as the sole source of moisture input. In contrast, the situation differs in forested areas where the correlation between NDVI and precipitation is often statistically not significant (p > 0.005) indicating that forests, because of their characteristics, are less dependent on the amount of precipitation. Regarding temperature, in agricultural areas, there is a positive correlation with NDVI, although it does not reach statistical significance. Conversely, in forested areas, a significant positive correlation is observed between NDVI and temperature which even positively contributes to the development of forest vegetation. In future, the recorded decline in precipitation (a substantial 22.72% drop) and the concurrent rise in temperature (up to 4.39 °C) in vegetation period, until 2100 might impact the reduction of NDVI.

Abstract

Oil pollutants affect the mechanical properties of soils differently. The effect of the kind of oil pollutants on the geotechnical characteristics of a type of soil is an interesting subject that has been examined less in previous studies. The results of this research can be used in designing structures built on soils that are likely to be contaminated with oil pollutants. This study comprehensively investigated the effect of the type of pollutants on the mechanical properties of sandy clay soil to provide the necessary parameters in the remediation plan for soils contaminated with various oil pollutants. A series of laboratory tests, including pH, standard compaction, one-dimensional consolidation, unconfined compressive strength (UCS), ultrasonic pulse velocity (UPV), falling head permeability, and direct shear, was conducted on the clean and polluted samples. Scanning electron microscopy (SEM) micrographs confirmed that oil pollutants change the soil structure into a flocculated but dispersed one. In addition to the low dielectric constant of oil pollutants, their high viscosity played an important role in altering the geotechnical parameters of clayey sand. The higher the viscosity of the oil pollutant, the higher the maximum dry density (MDD), cohesion coefficient, compression index (Cc), swelling index (Cs), and permeability coefficient of oil-polluted soil. The samples polluted with used motor oil and crude oil, due to their high viscosity, had the greatest drop in compressive strength and shear strength, respectively; whereas the kerosene-polluted sample, due to its low viscosity compared to other oil pollutants, had the greatest rise in compressibility. Thus, in geotechnical plans, special attention should be paid to the bearing capacity and settlement of clayey sand contaminated with crude oil and kerosene, respectively.

This study used parallel factor method (PARAFAC), self-organizing map (SOM), and random forest models to study the dissolved organic matter (DOM) sources and characteristics in rivers with varying non-point source inputs. The artificial canal Cihuai New River (CH) and the Gouqu (GQ) which are heavily polluted by agricultural surface sources were selected as the study objects. The PARAFAC model resolved four chemical components. C1 comprises two peaks, C1 (T1) (UVC fulvic acid) and C1 (T2) (humic-like acid). C2 includes two peaks, C2 (T1) (tyrosine-like protein) and C2 (T2) (tryptophan-like protein). C3 has two peaks, C3 (T1) (humic-like) and C3 (T2) (UVA fulvic acid). C4 is identified as humic-like fulvic acid. The SOM model shows that the degree of humification in the GQ, which is influenced by agricultural non-point source pollution, is higher than that of the unaffected CH. The primary source of humic substances in the river is agricultural non-point source pollution. CH is influenced by surrounding human activities and the eutrophication of water bodies, resulting in a higher level of autochthonous characteristics and biological activity in DOM. Random Forest model indicated that the C3 was the most sensitive (R² = 0.88) to river’s changes and therefore it is a good indicator of river’s water quality. And NH₄⁺ has a strong driving effect on the water quality of both rivers. Principal Component Analysis (PCA) reveals that the agricultural river DOM (GQ) is mainly composed of humic substances, while the artificial river DOM (CH) is predominantly derived from autochthonous sources. The combination of PARAFAC, SOM, and random forest methods helps overcome the limitations of traditional approaches and provides a scientific basis for the management of river water quality pollution.

Abstract

Agriculture is one of the most important production sectors in the world. Water and energy are two essential inputs for food production. The agricultural sector is influenced by climate change the most. In this regard, this research aimed to present a new mathematical programming approach to studying the effects of climate change on the water–energy–food (WEF) nexus. A sustainable WEF nexus was developed for the basin of Kashfrud in Razavi Khorasan province, Iran for 2019–2020. The present approach was modeled in several climatic-hydrological-economic-environmental sectors. Analyzing the outcomes of a hydrological model in the context of climate change scenarios reveals that, given the current state of irrigated land, there will be a 45% increase in net water demand in the future, accompanied by a 13% decrease in crop yields. Consequently, by embracing a holistic approach that considers the nexus of water, food, and energy, the net water demand drops to 71%, the energy allocation to agriculture decreases to 41%, greenhouse gas emissions are reduced by 32%, and farmers’ overall profits decrease by 73% in the face of climate change. This approach would also be effective in avoiding the undesirable effects of single-sectoral development policies in addition to improving resource use efficiencies. Since most non-renewable resources are consumed by the agricultural sector, the development of the nexus approach is also important from an environmental perspective in addition to the sustainability of resource use.

Abstract

Land use and land cover change (LUCC) have a significance influence on ecosystem services value. The Yangtze River Basin is an important ecologically sensitive area in China, and has experienced rapid land use change. How to understand the impact of land use change on ecosystem service value is of great significance for the utilization of ecological environment protection. In this study, based on the 2001–2018 land use data in the Yangtze River Basin and the revised ecosystem service value per unit area. The Land use change were analyzed and the ecosystem service value (ESV) were estimated in the Yangtze River Basin, Specifically, the spatiotemporal variation characteristics of ESV and the influence of LUCC on ESV were analyzed by using fishnet method, spatial autocorrelation analysis, high-low clustering, and hotspots methods. The results showed that the Yangtze River basin was dominated by forests, grasslands and croplands, with grasslands covering the largest area, about 60% of the basin. The expansion of urban and construction land was mainly due to the occupation of grassland and farmland around towns. ESV in the Yangtze River Basin increased by about 330.7 billion RMB, with grasslands and forests contributing the most to ESV throughout the study period. ESV in the Yangtze River Basin was mainly contributed by regulating services and supporting services, followed by supply services. The increase of regulating services was mainly due to the increase of wetland area, and the increase of supporting services came from the continuous expansion of forest area. The spatial distribution of ESV in the Yangtze River basin was positively correlated, with spatial aggregation and significant spatiotemporal differentiation of ecosystem service values in the study area. The results of the study can provide a reference for the optimization of land use structure and ecological environmental protection in the Yangtze River basin.

Abstract

Previous studies have demonstrated that schwertmannite (Sch) exhibits good adsorption performance for Cr(VI). In order to further enhance the ability to remove Cr(VI), this study prepared a novel composite (Fe(II)@Sch) by embedding ferrous iron (Fe(II)) on Sch. The adsorption performance of Cr(VI) on Fe(II)@Sch was investigated by batch adsorption experiments, and a possible removal mechanism was proposed through characterization analysis. The results showed that the optimal Fe/Sch ratio for Fe(II)@Sch preparation was 120 mmol/g. Fe(II)@Sch enabled efficient and rapid adsorption of Cr(VI). The maximum Cr(VI) adsorption capacity of Fe(II)@Sch was 4.17 mmol/g at pH 6.0, which was 69% higher when compared to Sch, and 81% of the maximum adsorption could be achieved within 1 min. The embedding of Fe(II) led to a decrease in the particle size and an increase in the specific surface area (SSA) of Sch, which could be considered favorable for adsorption. After four repeated cycles 93.3% of the original Cr(VI) adsorption capacity was still maintained. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy analysis showed that the interaction between Fe(II)@Sch and Cr(VI) followed an adsorption–reduction mechanism. The results demonstrated that Fe(II)@Sch could be used as an effective material for removing Cr(VI) from wastewater.

In recent years, the safe disposal of used face masks has become troublesome due to their non-biodegradable nature. This study focuses on the reuse potential of used face masks as a reinforcement to enhance the engineering properties of expansive soil treated with biopolymers such as Xanthan Gum and Guar Gum. The face masks were shredded into 5 × 5 mm chips and added to expansive soil at 0.5% by volume. A series of laboratory tests such as Unconfined Compressive Strength (UCS) Test, Splitting Tensile Test, Free swell Index (FSI) Tests, Swelling Pressure, Swelling Potential Tests, and California—Bearing Ratio (CBR) tests were performed for the evaluation of engineering behaviour of Shredded Face Mask Chips (SFMC) reinforced expansive soil treated with various dosages of Xanthan Gum and Guar Gum. The experimental test results showed that the inclusion of SFMC significantly improved the engineering characteristics of the soil. The maximum compressive strength and tensile strength have been attained at 2% inclusion of Xanthan gum and Guar gum into the expansive soil. The maximum values of compressive strength at optimum biopolymer content of 2% Xanthan gum and Guar gum were 369–437 kPa, respectively. The free swell index percentage for stabilized expansive soils with xanthan gum and guar gum decreased to 73.6–75.9%, respectively. The swell pressure of the treated soil showed up to a reduction of 90.2–94.1%. In all the tests, Guar Gum exhibited greater efficiency when compared to Xanthan Gum. Thus, the investigation results confirmed the efficient use of SFMC in biopolymer stabilization of expansive soil that would lead to the beneficial way for the safe disposal of used face masks.

Abstract

The adsorption to container walls, syringes, injectors and analytical columns by strongly hydrophobic organics in aqueous media presents challenges in accurate estimation of sorption parameters of chemicals such as chlorpyrifos (CPF). To minimize this phenomenon, mixed solvents and Teflon-lined centrifuge tubes were used. The study aimed at investigating the sorption kinetics and equilibrium parameters in tropical soils. In addition, the persistence and leaching potential of CPF under submerged and field capacity moisture conditions were studied. Batch sorption studies utilizing the Solvophobic theory revealed time-dependent kinetics on Teflon container walls, where CPF sorption diminished exponentially with increasing methanol fraction. Sorption parameters for soils showed diverse kinetics and equilibrium times across soils and methanol fractions. The Solvophobic theory was used to predict the soil-sorption coefficients K^W and K_OC. Chlorpyrifos sorption exponentially decreased with increasing methanol fraction, reaching equilibrium in 4–8 h. Container wall K^W measured was 0.19 mL/g, while soil K^W values ranged from 46.53 to 56.71 mL/g. Chlorpyrifos K_OC values varied from 1551 to 1890. The degradation studies under submerged and field capacity conditions indicated microbial and abiotic influences on chlorpyrifos persistence, resulting in half-lives ranging from 18 to 52 days in submerged conditions and 18 to 33 days at field capacity. The Groundwater Ubiquity Index suggested no leaching potential in the examined soils. This study represents the first investigation of chlorpyrifos sorption kinetics only Teflon-lined centrifuge tube container walls, revealing that chlorpyrifos sorption is not instantaneous but rather time-dependent. Future analyses should explore CPF's environmental fate, considering microbial interactions and organic matter content, to contribute to a comprehensive understanding and develop sustainable pest management strategies in tropical regions.

Graphical Abstract

Water contamination with hazardous dyes is a serious environmental issue that concerns humanity. A green technology to resolve this issue is the use of highly efficient photocatalysts under visible light to degrade these organic molecules. Adding composite and modifying shape and size on semiconductor materials are attempts to improve the efficacy of these compositions. The optical, microstructural and photocatalytic features of the compositions were investigated by several characterization procedures such as XRD, XPS, SEM, and TEM. Here, modifies Scherrer equation, Williamson–Hall (W–H), and Halder–Wagner method (H–W) have been used to investigate the crystal size and the micro-strain from the XRD peak broadening analysis. The average crystal size according to Modified Scherrer’s formula was 6.04–10.46 nm for pristine CdS and CdS/Gd2O3@GO, respectively. While the micro-strain (ɛ) corresponds to 3.88, 4.63, 4.03, and 4.15 for CdS, Gd₂O₃, CdS/Gd₂O₃, and CdS/Gd₂O₃@GO. It was also shown that the modest difference in average crystal size acquired by the Modified Scherrer and Halder–Wagner (HW) forms was related to differences in average particle size classification. As a result, the Halder–Wagner method was accurate in estimating crystallite size for the compositions. The average roughness is slightly changed from 4.4 to 4.24 nm for CdS/Gd₂O₃ and CdS/Gd₂O₃@GO, respectively. A kinetics investigation further revealed that the photocatalytic degradation of MB dyes was accompanied by a Langmuir isotherm and a pseudo-second-order reaction rate. The highest adsorption capacity (qe) determined for (type 1) CdS, Gd₂O₃, CdS/Gd₂O₃, and CdS/Gd₂O₃@GO adsorption was 5, 0.067, 0.027, and 0.012 mgg⁻¹, respectively. The R² values originated from the pseudo-second-order (type 2) for CdS, Gd₂O₃, CdS/Gd₂O₃, and CdS/ Gd₂O₃@GO were 0.904, 0,928, 0.825, and 0.977. As a result, the initial sorption rate (h) is altered between types 1 and 2. In type 2, the pseudo-second-order rate constant (k2) ranges from 0.005 for CdS to 0.011 for CdS/Gd₂O₃@GO. The Langmuir Hinshelwood and pseudo-second-order kinetic models describe the photodegradation process. The results demonstrate that the developed compositions can be used as a long-term substance for dye removal.

In this work, the photocatalytic degradation of amoxicillin (AMX), tetracycline(TCH), and diclofenac sodium(DCF) was studied using TiO₂ and Sn/Zn/Fe-doped TiO₂ as photocatalyst under ultraviolet (UV) and visible light. Photocatalysts were synthesized by sol–gel method and characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FTIR). Box–Behnken design (BBD) was used to achieve maximum %degradation by optimizing different parameters like the feed concentration (50–100 mg/L), feed pH (3–11), and the catalyst dosing (0.5–1.5 g/l). The study revealed that the Zn-doped TiO₂ photocatalyst (band gap of 3.23 eV) was the most effective which showed 90–95% degradation of all compounds within 90 min under UV radiation. Fe-doped TiO₂ (2.1 eV) and Sn-doped TiO₂(2.92 eV) showed the best results in the presence of visible light as it needs lower energy. To achieve maximum degradation efficiency under UV radiation, H₂O₂ (550 mL/L) was used along with Zn-doped photocatalyst under acidic conditions (at pH 3) for AMX, DCF, and basic conditions (at pH 11) for TCH. COD analysis was carried out before and after the experiment. COD removal efficiencies were found to be between 70–80% and liquid chromatography–mass spectrometry (LC–MS) analysis was performed to identify intermediate compounds formed during degradation.