This study investigates the validity of the EKC (environmental Kuznets curve) hypothesis for the 50 US states and a Federal District (Washington, D.C.). To this aim, the common correlated effects (CCE) and the augmented mean group (AMG) estimation procedures are applied between 1980 and 2015. While the CCE estimation does not support EKC hypothesis, the AMG does. The empirical findings of the AMG estimation indicate that only 14 states verify the EKC hypothesis. Additionally, the expected negative impacts of fossil energy consumption on the environment (CO₂ emissions) are strongly detected in all states except Texas. However, the expected positive impacts of renewable energy consumption on the CO₂ emissions are detected only in 13 states. Furthermore, the expected negative impacts of the population are not detected in some mostly populated states like New York, Texas, and Ohio. The overall findings of this study may help the US state-level policy makers in two ways: first, to understand whether their economic growths are sustainable (eco-friendly); second, to see how their fossil and renewable energy consumptions affect their environments and to review their energy policies.

In recent decades, climate change and environmental pollution have been at the center of global environmental debates. Nowadays, researchers have turned their attention to the linkage between real output and environmental quality and test the environmental Kuznets curve. Majority of the studies focus on a single pollutant aspect and measure the deterioration of the environment through carbon emission (CO₂) only. In contrary, the current study uses a comprehensive proxy, ecological footprint, to measure the environmental quality of the sixteen Central and Eastern European Countries (CEECs). The aim of this paper is to discover the impact of financial development, economic growth, and energy consumption (renewable and non-renewable) on the environment. In addition, for the first time, the current study includes biocapacity and human capital in the growth–energy–environment nexus in the case of CEECs. In doing so, we used annual data of sixteen CEE countries in perspective of the One Belt One Road (OBOR) initiative and cover the period of 1991–2014. For reliable findings, this study focuses on second-generation econometric approaches to check stationarity, cross-sectional dependency, and co-integration among the model parameters. The long-run estimations of the “Dynamic Seemingly Unrelated-co-integration Regression” (DSUR) signify that the effect of economic growth on ecological footprint is not stable and validate N-shaped relationship for cubic functional form between per capita income and ecological footprint (environmental quality). Empirical evidence divulges that financial development and energy use significantly contribute to environmental degradation while renewable energy improves environmental quality by declining ecological footprint significantly. Moreover, the significant effects of biocapacity and human capital are positive and negative on the ecological footprint, respectively. In robustness check through the “Feasible Generalized Least Square” (FGLS) and “Generalized Method of Moment” (GMM) models, we found consistent result. Lastly, the “Dumitrescu-Hurlin (D-H) Panel Causality Test” demonstrates that two-way causal relationship exists between EF and GDP, EF and FD, EF and EU, EF and BC, and EF and HC, while one-way causality is running from RE to EF. This study puts the present scenario of CEE economies in front of the policymakers and suggests that they should consider the vital role of renewable energy and human capital to get sustainability.

Placer gold mining is important anthropogenic sources of dust and metals that can strongly influence the environmental quality of the surrounding ecosystem. However, scarce studies have focused on evaluating the influence of placer gold mining on historical metal deposition in the surrounding ecosystem in the northern Great Hinggan Mountains, which is located at northeast of China. To address this research gap, four peatland cores with different distances to a gold placer in the northern Great Hinggan Mountains were selected in this study. Based on the ²¹⁰Pb depth-age model, historical variations in the Pb isotope and deposition fluxes of Pb, Cu, and Zn were reconstructed. The results show that metal deposition in the northern Great Hinggan Mountains was mainly influenced by the placer gold mining around the 1900s when the gold placer started to produce gold, and placer gold mining more seriously influenced the western sites that were closer to the placer gold mining. With increasing global metal productions after 1930, the proportion of the metals from placer gold mining sources gradually decreased, and part of Pb were transported via the atmosphere from other regions (e.g., Europe, East Asia). With the implementation of environmentally friendly policies and the decreasing anthropogenic production of Pb, Cu, and Zn around the world, deposition fluxes of these metals in the northern Great Hinggan Mountain began to decrease after 2000.

Exposure to pesticides is a major factor in the cause of dysfunction in the nervous system and neurodevelopment disorders in children at critical periods of great vulnerability. The aim of this study was to review scientific evidence published on neurodevelopmental effects of prenatal and postnatal exposure to organophosphate pesticides (OPs) in different stages, including neonates, infants, toddlers, preschool children, and school-age children. Full-text articles published in PubMed, Scopus, and ISI databases between 1973 and 2019 were reviewed and the scientific evidence was evaluated. Results: Fifty studies were eligible for inclusion in this quantitative synthesis. Fifteen of these papers evaluated the effects on neonates and infants, 18 on the effects on toddlers and preschool children, and 24 the effects on school-age children. Considerable evidence suggests that prenatal exposure to OPs contributes to child neurodevelopment disorders in all stages, whereas data about the effects of postnatal exposure are limited. Therefore, the available evidence supports the theory that sensitive time-windows occur prenatally rather than postnatally. Although 45 out of the total 50 selected articles found an association between OP exposure and child neurodevelopment, some of the evidence is controversial. A standardized methodology is needed to enable the comparison of the results in several studies, and further research studies are needed to warrant firmer conclusions. A systematic review of this evidence should be performed continuously to update the state of knowledge regarding neurodevelopmental effects associated with OP exposure.

Attention-deficit hyperactivity disorder (ADHD) of children is one of the most common neurodevelopmental diseases; the etiology remains unclear. We reviewed and meta-analyzed case-control studies to assess the effects of blood lead levels in children on ADHD symptoms. Relevant studies were identified by searching electronic databases. A meta-analysis was performed using the fixed model of Review Manager 5.3 software. Seven relevant studies were identified. The case groups exhibited significant increases in ADHD symptoms [mean difference (MD), 0.59; 95% confidence interval (CI), 0.50–0.68; p < 0.0001]. Subgroup assessment showed that even children with blood lead levels <3 μg/dL exhibited significant increases in ADHD symptoms (MD, 0.47; 95% CI, 0.39–0.56; p < 0.0001). Subgroup assessment also showed that children aged 5–12 years exhibited more significant increases in ADHD symptoms (MD, 1.35; 95% CI, 0.28–2.41; p < 0.0001) than children aged >12 years. Our findings suggest that low blood lead levels may be associated with ADHD symptoms in children. However, caution is needed when interpreting the results because among-study heterogeneity was in play. Primary interventions should focus on children with low blood lead levels.

Soils and different vegetable species in Costa de Caparica (Portugal) are subject to the intensive use of inorganic fertilizers and pesticides. Thus, the concentrations of As, Cu, Fe, Mn, Pb, and Zn were evaluated. Lettuce, spinach, and potatoes collected in station 9 cause reason for concern due to their high Pb concentrations close to 20 μg g⁻¹ which is probably related to an intensive use of copper and iron sulphate fertilizers. Additionally, the consumption of Portulaca oleracea collected in stations 3 and 4 must be avoided due to the high concentrations of Zn, and even Cu. The derived estimated daily intake (EDI) dose of Zn will be a risk to human consumption if P. oleracea was the single basis of a soup, although the addition of other ingredients might lower the tolerable upper intake (TUI) value of 39 mg/day of P. oleracea, to admissible levels, i.e., not exceeding 25 mg/day. Pumpkin collected in station 1 contained 44.1 μg g⁻¹ Cu and a TUI value of 9.8 mg/day, when the recommendation must not exceed 5.0 mg/day. In this context, it is strongly advised to not include this vegetable in household menus.

One of the most common compounds in pesticide formulations, plastics, and papers is 4-nonylphenol (4-NP). It is contained in agricultural, industrial, and wastewater effluents, which when discharged into surface waters affect aquatic fauna. Therefore, the present study aimed to use Biomphalaria alexandrina snails to evaluate the chronic toxicity of 4-NP. Its concentrations in collected water samples from Giza Governorate ranged from 400 to 1600 μg/l. Based on these environmentally relevant concentrations, laboratory experiments were carried out using standard 4-NP to investigate the effect of three concentrations; namely 400, 750, and 1600 μg/l. Survival rate of the exposed snails to 4-NP concentrations was affected after 4 weeks. Reproduction of the exposed snails to 4-NP concentrations was lower than that of the control at 30 °C, while the exposed snails to 400 μg/l of 4-NP showed maximum reproduction at 15 °C. The lowest hatchability percentage was recorded with egg masses laid by the exposed snails to 400 and 1600 μg/l of 4-NP at 15 and 30 °C, respectively. Furthermore, the results showed fluctuated levels of progesterone, estradiol, and testosterone depending upon the concentration and the temperature, which played a key role in determining the degree of 4-NP toxicity.

Intensive anthropogenic activities may add to pollution risks to lakes and rivers, which can be revealed by the magnetic characteristics of sediments. The present study aims to assess the pollution status of the sediment of a typical reservoir in northwestern China by application of magnetic susceptibility. The values of magnetic susceptibility exhibited significant positive correlations with trace metals (Co, Cu, Mn, Ni, and V) and natural radionuclides (²³²Th and ⁴⁰K). Multivariate statistical analysis indicated common sources and similar deposition characteristics of magnetic particles and trace metals. It was conformed that magnetic susceptibility could be used as an indicator to identify industrial sources of trace metals, but was not suitable to indicate the traffic or natural sources. Linear regression equations between the low-frequency magnetic susceptibility and the integrated pollution index as well as annual effective dose rate indicated a potential for using magnetic susceptibility in semi-quantitative assessment of trace metal pollution and radiological hazard in sediments. A three-step procedure is proposed for the use of magnetic susceptibility in pollution monitoring, which provides a fast and effective method for estimating the pollution extent and tracing the major sources of trace metals in the sediment of lakes and rivers.

To conduct a comprehensive ecological analysis on the solid residues derived from the thermal disposal of hyperaccumulator Pteris vittata, this study focused on the behaviors of As and Pb and the characteristics of environmentally persistent free radicals (EPFRs) in the solid residues under different thermal treatment conditions. The analysis results revealed that the concentrations of As in the biochars and bio-slag were approximately 350 and 1100 mg/kg, respectively. Moreover, the concentrations of Pb in the solid residues varied from 34 to 1050 mg/kg. According to the results of the modified BCR sequential extractions, As is more stable in the biochar while Pb is more stable in the combustion slags. In addition, As showed a higher volatilization temperature compared with Pb. The ecological risk assessment indicated that the correlation index between the contamination factor (Cf) of As and the risk index (R² = 0.995) is considerably larger than the correlation index between the contamination factor of Pb and the risk index (R² = 0.117), which implies that the pyrolysis method should be selected at priority. Moreover, the EPFR concentrations of the biochar declined by approximately 75 times when the pyrolysis temperature increased from 500 to 600 °C. This behavior indicated that high-temperature pyrolysis (> 600 °C) could simultaneously control both the heavy metal behavior and EPFR concentrations.

An unsafe level of manganese (Mn) was detected in the drinking water in some arsenic (As)-contaminated areas in Bangladesh. Mn is an essential trace element; however, the intake of a higher level of Mn through the drinking water is associated with the development of toxicity in humans. This study was designed to evaluate the effects of As and Mn co-exposure on neurobehavioral and biochemical alterations in a mouse model. Sodium arsenite (10 mg/kg body weight) and manganese chloride tetrahydrate (10 mg/kg body weight) were given to mice individually and in combination with drinking water for 90 days. Results showed that individual As and Mn exposure as well as co-exposure of As and Mn significantly (p < 0.05) reduced the percent of time spent in the open arms when compared with that of control mice. In addition, percent of time spent in open arms significantly (p < 0.05) increased in co-exposed mice compared with As exposure in elevated plus maze (42.05 ± 1.10 versus 38.94 ± 0.66). In the Morris water maze test, the mean time latency to find the platform was longer in metal-treated mice in comparison to that of control mice (p < 0.05). Importantly, the co-exposed group had shorter time when compared with the As-exposed group during the training periods (p < 0.05). Moreover, co-exposed mice stayed significantly (p < 0.05) more time in the target quadrant in the probe trial in comparison with that of As-exposed mice (27.25 ± 1.21 versus 23.83 ± 0.87 s) but less time than control mice (27.25 ± 1.21 versus 43.17 ± 1.49 s). In addition, a significant (p < 0.05) alteration of biochemical parameters such as ALT, AST, ALP, BChE, and SOD as well as urea and creatinine levels were noted in the As-exposed group compared with the control group and Mn significantly (p < 0.05) attenuated the effects of As in co-exposed mice. Therefore, the results of this study suggest that As and Mn may have some antagonistic effect and Mn could attenuate the As-induced neurobehavioral and biochemical alterations in co-exposed mice.