This study explores the interaction among coal consumption, pollutant emissions, and real income for South Africa in a multivariate setting. To achieve this objective, annual frequency data spanning from 1965 to 2017 is used for analysis. A series of econometrics tests were conducted ranging from stationarity and non-stationarity tests for unit root properties of the variables under consideration. Empirical evidence finds support for the inverted U-shaped pattern between energy consumption and environmental degradation in South Africa. The Toda-Yamamoto Granger causality test shows a feedback causality between economic growth and carbon dioxide emissions, as well as between GDP and coal consumption. All these highlighted findings have inherent environmental implications. Based on these outcomes, policy directions such as diversification of the South Africa energy mix to renewables and cleaner energy sources and also the adoption of carbon capturing and storage techniques were suggested to engender a cleaner and friendlier environment.

Heavy metals like Cd and Hg removal using novel graphene oxide/ferrous sulfate (GO/FeSO₄) was taken for experimental studies and analysis. In this work, GO/ FeSO₄ was synthesized by both modified Hummer’s and chemical precipitation method. The synthesized composite was characterized by field emission scanning electron microscope (FESEM), Fourier transform infrared (FTIR) spectroscopy, and Raman spectroscopy for their properties. Brunauer Emmett-Teller (BET) analysis was characterized for the surface analysis of the prepared nanocomposites. FESEM images exhibit flake-like structures in surface morphological studies. FTIR peaks confirmed the presence of carboxyl groups in GO. Raman spectroscopy intensity peak [ID/IG ratio1.18] confirmed the synthesized sample was GO. The experimental parameters such as initial concentration, pH, and adsorbent dosage were optimized to achieve maximum heavy metal removal efficiency. The influence of initial heavy metal concentration (0.2–1 mg/L), pH of solution (pH 3–7), and adsorbent dosage (1–5 g/L) was studied and reported. Adsorption kinetic studies were performed and the process was found to fit well with pseudo-second-order kinetics.

Soil-exchangeable aluminum (Al) has toxic effects on living organisms in acidic soils. Earthworm presence and activity can alter soil pH, which has a significant influence on Al toxicity. However, the effects of earthworms on soil Al toxicity and fractions are still largely unknown. This laboratory study focused on the effects of three earthworm species (endogeics Pontoscolex corethrurus and Amynthas robustus, anecis Amynthas aspergillum) on soil acidification, Al fraction distribution, and base cation release. Three native earthworm species and a soil (latosolic red soil) collected from a botanical garden in South China were incubated under laboratory conditions. After 40 days of incubation, six Al fractions in soil, namely exchangeable (AlEₓ), weakly organically bound (AlOᵣw), organically bound (AlOᵣ), amorphous (AlAₘₒ), Al occluded in crystalline iron oxides (AlOₓᵢ), and amorphous aluminosilicate and gibbsite (AlAₐg) fractions, were extracted using a sequential procedure. Soil pH; organic carbon; total nitrogen; total Al (AlTₒₜₐₗ); exchangeable K, Na, Ca, Mg contents; and CEC were determined as well. Compared to control soil, pH values increased by 0.79, 0.41, and 0.57 units in casts in the presence of P. corethrurus, A. robustus, and A. aspergillum, and 0.70, 0.32, and 0.50 units in non-ingested soil, respectively. Compared to control soil, the 61.7%, 30.7%, and 36.1% of AlEₓ contents in casts and 68.5%, 25.9%, and 39.0% of AlEₓ in non-ingested soil significantly decreased with the addition of P. corethrurus, A. robustus, and A. aspergillum, respectively. Moreover, compared to control soil, the 78.7%, 37.7%, and 40.1% of exchangeable Ca²⁺ and 12.3%, 24.7%, and 26.8% of exchangeable Mg²⁺ contents in casts significantly increased with the presence of P. corethrurus, A. robustus, and A. aspergillum, respectively. Soil treated with P. corethrurus had higher soil pH values, exchangeable Ca²⁺ contents, and lower AlEₓ than those with A. robustus and A. aspergillum. Results of principal component analyses showed that P. corethrurus, A. robustus, and A. aspergillum casts and non-ingested soil differ for soil pH, Al fractions, and exchangeable base cations release. These results indicate that earthworms, especially P. corethrurus, can reduce soil Al toxicity, increase soil pH, and affect the release of exchangeable base cations.

Applying a global DEA model based on non-radial directional distance function, this paper constructs a comprehensive efficiency index to estimate green development level and further identifies the influencing mechanism of technology R&D on green development in China’s industrial sector. The results demonstrate that the level of green development in China’s industrial sector declined year by year and the average was 0.27, and it also shows significant regional characteristics within the sample period. Besides, the environment pollution transferred from the east to the central and the west. In addition, the results also indicate that there is a threshold effect for the impact of technology R&D on China’s industrial green development. Based on the volume of the trade openness, this effect presents a “N”-type characteristic that tilts to the right. According to the research results, the corresponding policy recommendations are put forward, which may be of great importance to improve the green development level in China’s industrial sector.

Cave dwelling is an ancient and unique type of residence in the Loess Plateau of Northern China, where the economics are less-developed. The majority of the local dwellers rely on traditional solid fuels for cooking and heating, which can emit large amounts of particles into both indoor and outdoor environments. In this study, we measured the real-time household concentrations of PM₂.₅ and explored the association between personal daily PM₂.₅ exposure and blood pressure (BP). Cooking and heating activities with different energies made a great variation in the household PM₂.₅ air pollution, and residents using biomass had the highest personal PM₂.₅ exposure. Temperature and relative humidity are both significantly linear correlated with household PM₂.₅ air pollution. Besides, systolic blood pressure (SBP) was demonstrated to be positively associated with personal PM₂.₅ exposure: with each 10-μg/m³ incremental PM₂.₅ concentration when controlling all the other factors, SBP will increase by 0.36 mmHg (95% confident interval (CI) 0.05–0.0.77 mmHg). If solid fuels could be replaced with clean energies, personal PM₂.₅ exposure and SBP would reduce by more than 21% and 3.7%, respectively, calling for efficient intervention programs to mitigate household air pollution of cave dwellings and protect health of those residents.

In this study, copper oxide nanorods were synthesized via surfactant-assisted chemical precipitation method and characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and UV-Visible spectrometer. XRD result reveals that CuO nanorods were structured in the monoclinic phase. SEM image suggested that synthesized CuO were shaped like nanorod with approximately 20–40 nm width and 500–800 nm length. The observed band gap calculated from UV-Visible absorption studies is 1.45 eV. As-prepared CuO nanorods were applied as a photocatalyst for the degradation of textile dye Reactive Black 5 (RB-5) in aqueous solution under the presence of visible light. The result exhibited that an enhanced degradation of RB-5 was achieved around 98% within 300 min and the experimental values were well matched with the linear fit model (R² = 0.97) and the observed rate constant found to be 5 × 10⁻³ min⁻¹. Therefore, as-synthesized CuO nanorods can be applied as a potential photocatalyst material for the degradation of organic pollutants in the wastewater.

Chlordecone, an organochlorine insecticide, was widely used in the French West Indies banana plantations. We set up a cohort of banana plantation workers who worked between 1973 and 1993, the period of authorized use of chlordecone. Vital status and causes of death were collected from French national registries. Workers were followed up from 1 January 2000 to 31 December 2015. Cause-specific mortality in the cohort was compared to that of the general population of the French West Indies by computing standardized mortality ratios (SMRs). A total of 11,112 workers (149,526 person-years, 77% men) were included in the mortality analysis, and 3647 deaths occurred over the study period. There was a slight deficit in all-cause mortality, which was statistically significant in men (SMR = 0.93, 95% CI 0.89–0.96), but not in women (SMR = 0.96, 95% CI 0.89–1.04). All-cancer mortality did not differ significantly from that of the general population (men: SMR = 0.96, 95% CI 0.90–1.03; women: SMR = 1.04, 95% CI 0.89–1.21). Significant excesses of deaths were observed for stomach cancer in women (SMR = 1.94, 95% CI 1.24–2.89) and pancreatic cancer in women farm owners (SMR = 2.31, 95% CI 1.06–4.39). Mortality from prostate cancer was similar to that of the general population in the whole cohort (SMR = 1.00; 95% CI 0.89–1.13) and non-significantly elevated among farm workers (SMR = 1.10, 95% CI 0.87–1.36). Non-significant increases in mortality were also observed for lung cancer in women, leukemia in men, and non-Hodgkin lymphoma in both genders.

This paper investigates the convergence of per capita renewable energy consumption across 15 core EU member countries over the period 1990–2018. In addition to the traditional convergence tests, this paper employs a Lagrange multiplier (LM)–based panel unit root test that allows for two endogenously determined structural breaks to test for the stochastic convergence. Given the shortcomings of stochastic convergence tests in light of the possibility of multiple equilibria associated with groups of countries following different convergence paths, the club convergence algorithm is also employed. Traditional cross-sectional tests indicate that both β- and σ-convergence of per capita renewable energy consumption exist across the EU-15 countries. Moreover, the results of stochastic convergence tests reveal that relative per capita renewable energy consumption is converging across the sampled countries over the sample period. However, the club convergence test results suggest the rejection of full panel club convergence and the presence of a certain number of clubs for the variable of interest.

Recently, Dr. Yuh-shan Ho discussed the search methods of the paper “Dynamic analysis of international green behavior from the perspective of the mapping knowledge domain” Li et al. (Environ Sci Pollut Res 26:6087–6098, 2019a). In fact, Ho and co-workers have used the search methods in several papers Ivanović et al. (Scientometrics, 105:145–160, 2015); Monge-Nájera & Ho (Rev Biol Trop 63:1255–1266, 2015); Ho & Hartley (Br J Psychol, 107:768–780, 2016). In order to reply to the comments, this letter supplementarily explains the characteristics, scope, and limitations of search methods. In addition, the letter states that researchers can use improved methods suggested by Dr. Ho in future studies.

A series of environmental protective policies have been taken recently in the Pearl River Estuary (PRE) to alleviate water pollution; however, their influence on the reduction of heavy metals in estuarine water has not been known. This study selected Guangzhou as a representative city in the PRE and collected estuarine water monthly from 2008 to 2017 to track the variation of As, Hg, Pb, Cd, Cu, Zn, and Se. During the last decade, the high time-resolved record showed that the concentration of Hg, Pb, Cd, Cu, and Zn in estuarine water reduced by 39.5%, 91.0%, 86.2%, 74.6%, and 97.3%, respectively. However, the concentration of As kept in a stable range (1.89–2.69 μg L⁻¹) and Se (0.17–0.65 μg L⁻¹) increased slightly. The principal component analysis (PCA) and absolute principal component scores-multiple linear regression (APCS-MLR) results suggested that the upstream industrial effluents were major sources for Hg (45.5–92.7%), Pb (47.3–100%), Cd (42.0–90.6%), Cu (85.5–100%), and Zn (100%) and the geogenic source was major origin for As (84.6–98.3%) and Se (0–67.5%). The risk quotient of Hg, Pb, Cd, Cu, and Zn to aquatic organisms largely decreased from 0.03, 0.59, 0.03, 2.06, and 0.26 in 2008 to 0.02, 0.05, 0.006, 0.52, and 0.007 in 2017, respectively. The effective control of heavy metal pollution in the study area can be primarily due to the relocation of hundreds of polluting factories during the last decade.