Carbon intensity refers to the carbon emission of per unit output generated by a country or a region. It shows the economic system’s close connection with carbon emission and its direct or indirect influence on environment. The carbon intensity curves of many countries visually show significant features of convergence. In order to strictly testify this phenomenon, this thesis chronologically defines convergence of carbon intensity and testifies it with endogenous growth model as theoretical basis. To realize the empirical test on convergence of carbon intensity, the author selects 24 countries as test samples and divides them into 3 groups, on which σ convergence test and cointegration test are conducted. Test result shows that convergence of carbon intensity exists in countries with high or medium high income, while countries with medium or low income shows insignificant convergence tendency in carbon intensity. Besides, σ convergence test demonstrates the time and degree ranking of convergence of carbon intensity of the 3 groups, which provides a concrete referential standard for countries to analyze and control changes in carbon intensity.

Under the background of global climate change, the present study aimed to evaluate the effects of daily mean temperature and diurnal temperature range (DTR) on the non-accidental mortality. Poisson generalized linear model (PGLM) combined with distributed lag non-linear model (DLNM) was used to evaluate these effects after adjusting the relative humidity and major air pollutants. All effects were presented as relative risk (RR), with 75th percentiles of daily mean temperature and DTR compare with their lowest RRs corresponding values. Daily mean temperature was associated with the non-accidental mortality with a U-shaped curve, and the non-accidental mortality increased by 1.8% (95% CI: 0.7~3.0%) when the temperature was 24.4 °C (20 °C as the reference). Additionally, the non-accidental mortality increased by 1.4% (95% CI: 0.1~2.7%) on lag6 day when DTR was 11.3 °C (7 °C as the reference). The elderly (≥ 65 years) were more susceptible to daily mean temperature and DTR, and females were more susceptible to high DTR effect than males. Our study provides evidence that daily mean temperature and DTR are significantly associated with non-accidental mortality and have delayed effects. Both females and elderly people are vulnerable to the potential adverse effects.

Plants play a fundamental role by intercepting air particulate matter (PM) and improving air quality. The link between the accumulation of pollutants and the leaf exposure time to air pollution remains unclear as it depends on different factors. The aim of this study is to test if the metal and PM accumulation in holm oak leaf is linked to exposure time to air pollution. For this study, 1- (1y) and 2-year (2y) old holm oak leaves were sampled in an urban area near Naples. Those leaves were analyzed to measure the amount of particulate matter (PM₂.₅–₁₀ and PM>₁₀) and the Cr, Cu, Mn, and Ni metal concentrations. The results displayed that leaf Cr, Cu, and Mn accumulation are linked to exposure time, whereas leaf PM deposit was not directly linked to the exposure time. PM deposit on leaves could be influenced by rainfall events or by the saturation of leaves’ surface.

In this study, several immobilized ionic liquid adsorbents on carbon materials were synthesized with impregnation method. The carrier materials were activated carbon and three kinds of multi-walled carbon nanotubes. And the synthetic adsorbents immobilized different kinds of ionic liquids were characterized by Boehm titration, FT-IR, XPS, TG, and BET analysis, respectively. Finally, carbon materials after [C4mim]HSO₄ immobilization were selected as adsorbent to remove Hg²⁺ from water phase. The optimum conditions of adsorption test of ionic liquid immobilized by multi-walled carbon nanotubes were as follows: the initial concentration of Hg²⁺ was 400 mg/L, the adsorbent addition amount was 40 mg, the temperature was 20 °C, the reaction time was 200 min, the removal rate of Hg²⁺ peaked at 62.95%, the adsorption capacity was reached 79.00 mg/g. The optimum conditions of adsorption test of ionic liquid immobilized by activated carbon were as follows: the initial concentration of Hg²⁺ was 300 mg/L, the adsorbent addition amount was 0.2 g, the temperature was 20 °C, pH was 2.0, the reaction time was 100 min, the removal rate of Hg²⁺ was more than 99%, the adsorption capacity was 118.65 mg/g. The adsorption isotherm fitting study found that the adsorption of adsorbent on Hg²⁺ was more in line with the Langmuir model, and the adsorption kinetics study shows that the adsorption process is consistent with the pseudo-second-order kinetic equation. The results of kinetic analysis are further verified by thermodynamic analysis.

In the present investigation, the spatial distribution of the nest of White Stork Ciconia ciconia was examined. Spearman’s rank-order correlations test and the principal component analysis (PCA) were applied to a total of 227 nests recorded in the Guerbes-Sanhadja wetland eco-complex, northeastern of Algeria, over seven sites, for which the percentage of occupied nests reaches 89% (202 nest were occupied). Our goals are twofold: to explore the variation and distribution of the structure supporting the nest and to explain their spatial variability. The Spearman’s rank-order correlation test show that steel electricity poles had non-significant correlations with tree, and only concrete electricity poles structure had statistically significant positive correlation with mobile phone antennas structure (R = 0.757; at p < .05), and the roofs of houses had statistically significant positive correlation with mobile phone antennas structure (R = 0.825; at p < .05). According to the PCA results, it was observed that the PC1, which explains 50.86% of the total inertia, further represents and synthesizes the dominant structure supporting the nest, i.e., tree, steel electricity poles, and concrete electricity poles, which were strongly correlated with PC1, having a component loading nearly equal to 0.766, 0.821, and − 0.929, respectively, while the PC2, which explains 30.30% of the total inertia, includes the structure rarely recorded in the studied region, i.e., wooden electricity poles and the roofs of houses.

DEHP is a wildly used plasticizer. Maternal DEHP exposure induced fetal growth restriction (FGR) and behavioral abnormalities in adolescence and adulthood mouse. The effect of low birth weight induced by DEHP on behaviors after growing up is not certain. In this study, the ICR pregnant mice were exposed to 200 mg/kg DEHP during gestation 6–12 days or 13–17 days, which can create FGR model. The F1 offspring were performed three ethological experiments at puberty (6 weeks postpartum) and adult period (8 weeks postpartum). The open field test was performed to detect the locomotor activity and anxiety, the elevated plus maze to test anxiety-like behavior, and the Morris water maze assay to measure the spatial learning and memory capability of male and female offspring. The results showed that spatial memory ability was dramatically impaired for male rather than female offspring in gestation 13–17 days’ group. Other behaviors had no statistically different between groups. These findings suggest that prenatal DEHP exposure disturbed mouse offspring spatial memory ability in a phase- and gender-dependent manner.

Soil potentially toxic metals (PTMs) pollution caused by anthropogenic activities has become serious concern with respect to the crop safety production. In this study, an emerging biochar derived from kiwi pruning branches waste was employed as amendment aiming to evaluate its remediation potential on smelter- and mining-contaminated soils. The effect of biochar on the soil physicochemical properties, leachability, and chemical fractions acted on stabilization practice of PTMs in soil was investigated. The results showed that the addition of biochar increased the soil pH, cation exchange capacity, organic matter, and enzymatic activities (dehydrogenase, urease, and sucrase) but reduced the extraction toxicity of PTMs in both smelter (Fengxian, FX) and mining (Tongguan, TG) soils. The fraction analysis showed that the maximum reduction of exchangeable fraction of Cd, Zn, and Pb in the 4% biochar amended soils decreased by 11.1, 13.3, and 24.7% in FX soil and 7.67, 22.8, and 7.89% in TG soil, respectively, in comparison with to control (no biochar added). Additionally, the residual fraction of Cd, Zn, and Pb increased by 55.9, 7.14, and 11.0% in FX soil and 23.7, 5.86, and 10.0% in TG soil, respectively. The further greenhouse experiment showed that the Indian mustard (Brassica juncea) production increased with the increasing application dosages of biochar, while the PTMs uptakes in plant notably decreased after amendments. Conversion of kiwi pruning branches waste into emerging biochar benefits the agricultural waste recycling utilization and enhances PTMs-contaminated soil remediation in practice. Graphical abstract

With the continued growth of cities in many areas of the world, it is important to understand variations in atmospheric deposition in relation to site-specific geographic factors. Accordingly, this research investigated wet or bulk deposition (WD/BD) and dry deposition (DD) of SO₄²⁻, NO₃⁻, and NH₄⁺ onto Japanese cedar within the Tokyo metropolis and surrounding areas with the primary aim of evaluating which geographical factors most influence the deposition of pollutants. Two new sites were established and, along with five existing sites, comprised an array of sites with varied geographic settings (distance from the center of Tokyo, elevation, and azimuthal difference between slope aspect and dominant wind direction). Annual WD/BD and DD values of SO₄²⁻, NO₃⁻, and NH₄⁺ ranged from 9–35, 16–83, and 12–96 mmol m⁻² year⁻¹, respectively, and 1–25, − 5–104, and − 7–142 mmol m⁻² year⁻¹, respectively. Annual WD/BD values only showed a statistically significant difference with azimuthal difference for SO₄²⁻ and NH₄⁺. In contrast, annual DD values of SO₄²⁻, NO₃⁻, and NH₄⁺ were found to significantly decrease with distance from the center of Tokyo. In addition, site elevation was a significant factor influencing the DD of SO₄²⁻, NO₃⁻, and NH₄⁺ in linear regression models. Azimuthal difference was not significantly related to DD variability. Given these results, it is necessary to consider both the distance from emission source as well as the geographic factors of particular locations when evaluating the deposition of atmospheric pollutants from megacities to forested areas within and beyond the city.

Hydrotalcite-like compounds are a group of layered double hydroxides widely studied as sorbents to remove organic and inorganic contaminants under laboratory conditions. This study is a proof-of-concept of the long-term fate of hydrotalcite compounds under natural environmental conditions, to bridge the gap between laboratory studies and their field application as sorbents. Hydrotalcite (HT) with intercalated carbonate species (HT-CO₃) and dodecyl sulphate (HT-DS) were synthesised and placed in two groundwater monitoring wells in Denmark, one contaminated with chlorinated hydrocarbons and another with uncontaminated groundwater. To assess the structural and surface compositional changes of hydrotalcite compounds upon prolonged exposure to groundwater, the material was analysed with powder X-ray diffraction (PXRD), Fourier-transformed infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The results showed that the stability and dissolution behaviour of hydrotalcite compounds under groundwater conditions depended on the intercalated anion (CO₃²⁻ > DS) and groundwater dynamics (static flow > dynamic flow), while the hydrotalcite aggregate size only had a minor effect. Groundwater geochemistry influenced the precipitation of insoluble species (CaCO₃, and adsorbed sulphate) on the hydrotalcite surface. The instability of hydrotalcite compounds, especially in the case of HT-DS, may constitute a significant limiting factor on their future application as sorbents under dynamic flow conditions.

Cadmium (Cd) and zinc (Zn) toxicity causes physiological disorders and harms plants, interfering with the rehabilitation of areas affected by mining activities. This study evaluated how the exposure to Zn and/or Cd affects the growth of native andropogon grass (Andropogon gayanus Kunth) plants originally found in areas contaminated with Cd and/or Zn due to zinc mining activities. Plants were cultivated for 7 weeks in a nutrient solution treated with Zn (142.3–854.0 μM) or Cd (0.9–13.3 μM) separately or combined with a molar ratio of 64:1 (Zn:Cd). A control treatment was grown in a complete Hoagland and Arnon solution (without Cd). Plant height, stem diameter, internode length, dry weight, Cd and Zn concentration, and accumulation in shoots/roots, as well as ultrastructure of roots and leaves were analyzed at the end of the experiment. The root dry weight was not significantly affected by the addition of the metals. Moreover, Zn provided higher shoot dry weight (up to 160%) relative to control. Andropogon grass tolerated both metals better separately than when applied together. Transmission electron microscopy analyses showed modifications such as vesiculation and vacuolation in the ultrastructure of andropogon tissues by Cd and/or Zn. The andropogon grass was tolerant to the doses tested, evidencing that it has potential for recovering areas contaminated with Zn and/or Cd.