Diverse impact of greenhouse gasses (GHGs) over the landscape of environment is generally believed in literature. As CO2 emission acutely leads to GHGs is a major contributor for global warming, it creates a serious pressure on natural resources and ecological settings. Similarly, low-carbon (CO2) economy, plenty of energy resources, and sustainable growth are a big ask for worldwide economies in this era of mechanization. This paper analyzes the Environmental Kuznets Curve (EKC) hypothesis, for Belt and Road Initiative (BRI) economies, to contend the role of mega projects in BRI as an attribute for ecological detriments. The on-hand study engages fresh data information ranging from 1981 to 2016 holding with heterogeneity and cross-sectional dependence as a special deliberation. The calculated outcomes expose that, mean group estimator provides strong evidence and favor the existence of EKC approximately in every region. The long-run influence is measured by pooled mean group estimators, which shows significant outcomes in every region; additionally, the EKC hypothesis affirmed in the long run especially for developed economies. Mega projects, i.e., BRI requisite immense energy sources to accomplishing the enclosed projects efficiently and effectively. The positive association between carbon emission and energy consumption troubled the governments to make policies for restraining the magnitude of carbon emission and controls energy usage for enduring environment to its original position. Next, the valuations depicted the dense recommendations for state administrations in capacity of rigorous level supremacy, trash managing campaigns, renewable energy reliance, and advance for desirable judgments to sterilize the atmosphere.

The present study compared blood plasma metals in children with autism spectrum disorder (ASD) with those in unaffected children in Shenzhen (China). Factors associated with the metal bioaccumulation were further investigated. Thirty-four blood samples of children with ASD were collected in a local hospital (Shenzhen Children’s Hospital), while those of 38 unaffected children were from a local large public kindergarten, during March to April in 2016. Metal analysis was carried out by inductively coupled plasma-optical emission spectrometry. The results showed that children with ASD had higher (P < 0.01, 0.05) Pb (ASD 31.9 μg/L, unaffected children 18.6 μg/L), Hg (3.83, and 1.09 μg/L), and Cd (0.70 and 0.26 μg/L) than unaffected children, while essential elements Zn (ASD 4552.0 μg/L, unaffected children 5118.6 μg/L), Se (61.7 and 90.6 μg/L), and Mn (13.5 and 21.4 μg/L) showed an opposite pattern. Moreover, the children exposed to passive smoking had higher (P < 0.05) Cd (passive smoking 1.08 μg/L; non-passive smoking 0.22 μg/L) than those without the exposure. Positive associations were found between levels of Hg or Pb and seafood consumption as well as body mass index (BMI). More future work is needed in order to clarify the association between metal exposure and ASD occurrence in China.

Although thallium (Tl) is a highly toxic element, little information is available on the environmental risks of Tl in agricultural soils with intensive practices, particularly nearby mining sites. Therefore, we investigated the potential release of Tl in acidic soils with intensive cultivation nearby a waste copper mining site from southern China based on its level and chemical fractions as well as simulated release under artificial acid rain. Results showed that the average Tl content was 1.31 mg/kg in the studied area, which significantly exceeds the permissible thallium value of 1 mg/kg for agricultural soil in China. Some vertical increases of soil Tl from different land uses indicate the potential transport of Tl downward to groundwater. High positive correlations between surficial soil Tl and rubidium (Rb) and copper (Cu) indicated that Tl has the lithophile and chalcophile behavior. Tl in soils is mainly entrapped in residual fraction. The exchangeable fraction of Tl in agricultural soils was less than undisturbed natural soils and copper mined soils. Additionally, the percentage of Tl release from undisturbed natural soils and soils of copper ore area was more than that from agricultural soils in simulated acid rain. Furthermore, the releases of Tl from the soils increased with the acidity of artificial acid rain. Thus, more attention must be paid to land management of this similar area to avoid the risk of Tl impact on human health.

The dechlorination of chlorinated organic pollutants by zero valent iron (ZVI) is an important water treatment process with a complex dependence on many variables. This complexity means that there are reported inconsistencies in terms of dechlorination with ZVI and the effect of ZVI acid treatment, which are significant and are as yet unexplained. This study aims to decipher some of this complexity by combining Raman spectroscopy with gas chromatography-mass spectrometry (GC-MS) to investigate the influence of the mineralogy of the iron oxide phases on the surface of ZVI on the reductive dechlorination of pentachlorophenol (PCP). Two electrolytic iron samples (ZVI-T and ZVI-H) were found to have quite different PCP dechlorination reactivity in batch reactors under anoxic conditions. Raman analysis of the “as-received” ZVI-T indicated the iron was mainly covered with the ferrous oxide (FeO) wustite, which is non-conducting and led to a low rate of PCP dechlorination. In contrast, the dominant oxide on the “as-received” ZVI-H was magnetite which is conducting and, compared to ZVI-T, the ZVI-H rate of PCP dechlorination was four times faster. Treating the ZVI-H sample with 1 N H₂SO₄ made small change to the composition of the oxide layers and also minute change to the rate of PCP dechlorination. However, treating the ZVI-T sample with H₂SO₄ led to the loss of wustite so that magnetite became the dominant oxide and the rate of PCP dechlorination increased to that of the ZVI-H material. In conclusion, this study clearly shows that iron oxide mineralogy can be a contributing factor to apparent inconsistencies in the literature related to ZVI performance towards dechlorination and the effect of acid treatment on ZVI reactivity.

Concerns about motor vehicle emissions on human health are typically focused on aerial pollution and are regulated via controls on tailpipe emissions. However, vehicles also contribute heavy metal emissions through non-tailpipe pathways (e.g., brake wear, tire particulates). The metal pollutants produced via both tailpipe and non-tailpipe pathways pose threats to both human and ecosystem health long after they have settled from the atmosphere largely via contamination of soils and plants. In this study, we examined the effect of vehicular pollution on soils and plants in five paired sites in Gaviota, CA. In each site, we examined the effect of proximity to road on heavy metal concentrations (cadmium, nickel, lead, and zinc) in four of the most common roadside plant species—Melilotus indicus, Herschfeldia incana, Avena sativa, and Artemisia californica—as well as on soil metal concentrations. Then, to look at potential effects of road proximity and associated metal pollution on plants, we also examined the carbon and nitrogen ratios of all the plant samples. We found strong and significant effects of proximity to road on concentrations of all heavy metals in plants; plants in close proximity to roads had metal concentrations between 8 and 11 times higher than plants farther from roads. Plant C:N ratios also varied strongly among site types and were always higher in close proximity to roads as compared to farther off roads, potentially indicating broader effects of road proximity to plant ecology and leaf quality for consumers in the region.

Heavy metal contamination in soils/sediments and its impact on human health and ecological environment have aroused wide concerns. Our study investigated 30 samples of soils and sediments around Dongting Lake to analyze the concentration of As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn in the samples and to distinguish the natural and anthropogenic sources. Also, the relationship between heavy metals and the physicochemical properties of samples was studied by multivariate statistical analysis. Concentration of Cd at most sampling sites were more than five times that of national environmental quality standard for soil in China (GB 15618-1995), and Pb and Zn levels exceeded one to two times. Moreover, Cr in the soil was higher than the national environmental quality standards for one to two times while in sediment was lower than the national standard. The investigation revealed that the accumulations of As, Cd, Mn, and Pb in the soils, and sediments were affected apparently by anthropogenic activities; however, Cr, Fe, and Ni levels were impacted by parent materials. Human activities around Dongting Lake mainly consisted of industrial activities, mining and smelting, sewage discharges, fossil fuel combustion, and agricultural chemicals. The spatial distribution of heavy metal in soil followed the rule of geographical gradient, whereas in sediments, it was significantly affected by the river basins and human activities. The result of principal component analysis (PCA) demonstrated that heavy metals in soils were associated with pH and total phosphorus (TP), while in sediments, As, Cr, Fe, and Ni were closely associated with cation exchange capacity (CEC) and pH, where Pb, Zn, and Cd were associated with total nitrogen (TN), TP, total carbon (TC), moisture content (MC), soil organic matter (SOM), and ignition lost (IL). Our research provides comprehensive approaches to better understand the potential sources and the fate of contaminants in lakeshore soils and sediments.

Due to constraints of fresh water for agricultural irrigation, wastewater was used for irrigation of agricultural land as alternative water resources in arid and semi-arid Tunisian regions. However, long-term irrigation may cause contamination by heavy metals in the soil as well as for crops, thus becoming a threat to humans. To understand the effect of irrigation with wastewater on the concentrations of heavy metals Cr, Cu, Mn, Zn, and Pb, in soil and plants, soil samples and plants were collected and analyzed. Results have shown that all soil samples do not exhibit extreme values. The content of heavy metals in the surface layer (0–30 cm) is much higher than that in depth. Overall, the concentrations of Mn, Pb, Cu, Cr, and Zn in soil were found to be lower than the authorized national safety limits. Moreover, the content in both parts of forage crops have not exceeded the WHO standard. For olive trees, no negative values were found in the different organs, which was also true for the extracted oil. An exception happened for the oils produced from fallen olives in direct contact with the wastewater and the soil. Therefore, to ensure food security and wastewater use for irrigation, monitoring and control of pollution is required. Graphical abstract Biomass production from treated wastewater without risk

Polycyclic aromatic hydrocarbons (PAHs), a large group of persistent organic pollutants (POPs), have caused wide environmental pollution and ecological effects. Chromophoric dissolved organic matter (CDOM), which consists of complex compounds, was seen as a proxy of water quality. An attempt was made to understand the relationships of CDOM absorption parameters and parallel factor analysis (PARAFAC) components with PAHs under seasonal variation in the riverine, reservoir, and urban waters of the Yinma River watershed in 2016. These different types of water bodies provided wide CDOM and PAHs concentration ranges with CDOM absorption coefficients at a wavelength of 350 nm (a CDOM(350)) of 1.17–20.74 m⁻¹ and total PAHs of 0–1829 ng/L. CDOM excitation-emission matrix (EEM) presented two fluorescent components, e.g., terrestrial humic-like (C1) and tryptophan-like (C2) were identified using PARAFAC. Tryptophan-like associated protein-like fluorescence often dominates the EEM signatures of sewage samples. Our finding is that seasonal CDOM EEM-PARAFAC and PAHs concentration showed consistent tendency indicated that PAHs were un-ignorable pollutants. However, the disparities in seasonal CDOM-PAH relationships relate to the similar sources of CDOM and PAHs, and the proportion of PAHs in CDOM. Overlooked and poorly appreciated, quantifying the relationship between CDOM and PAHs has important implications, because these results simplify ecological and health-based risk assessment of pollutants compared to the traditional chemical measurements.

In the present study, we have reported an eco-friendly, rapid, and simple method for the synthesis of silver nanoparticles (AgNPs) using Bauhinia purpurea flower extract as non-toxic bioreducing agent. The formation of AgNPs was confirmed by UV–visible spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy and energy-dispersive spectroscopy (SEM–EDS), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD). The synthesized AgNPs were spherical in shape with an average size of 20 nm. Furthermore, the antibacterial activities of the synthesized AgNPs (2–10 mM) against clinical pathogens, Klebsiella sp. and Staphylococcus sp., were evaluated under in vitro conditions.

Mining of Cu took place in Kvalsund in the Arctic part of Norway in the 1970s, and mine tailings were discharged to the inner part of the fjord, Repparfjorden. Metal speciation analysis was used to assess the historical dispersion of metals as well as their potential bioavailability from the area of the mine tailing disposal. It was revealed that the dispersion of Ba, Cr, Ni, Pb and Zn from the mine tailings has been limited. Dispersion of Cu to the outer fjord has, however, occurred; the amounts released and dispersed from the mine tailing disposal area quantified to be 2.5–10 t, less than 5% of Cu in the original mine tailings. An estimated 80–390 t of Cu still remains in the disposal area from the surface to a depth of 16 cm. Metal partitioning showed that 56–95% of the Cu is bound in the potential bioavailable fractions (exchangeable, reducible and oxidisable) of the sediments, totalling approximately 70–340 t, with potential for continuous release to the pore water and re-precipitation in over- and underlying sediments. Surface sediments in the deposit area were affected by elevated Cu concentrations just above the probable effect level according to the Norwegian sediment quality criteria, with 50–80% Cu bound in the exchangeable, reducible and oxidisable fractions, potentially available for release to the water column and/or for uptake in benthic organisms.