Endogenous pollution is one of the most notable issues in drinking water reservoirs, since the sediment is a main sink of contaminants in the aquatic environment. In this work, we investigated the spatial distribution characteristics of heavy metals and different species of N and P and assessed the pollution risks of the sediments from the Chenhang Reservoir, which is the first drinking water reservoir supplied by Yangtze River in Shanghai, China. The results show that heavy metals, including Cu, Pb, Zn, Mn, and Fe, were mainly accumulated in the downstream, while most Ni and Cr were concentrated in the sediments from the central and western zones. Total N in the sediments was primarily distributed in the eastern reservoir, while ammonia N and most of total P were accumulated in the central and eastern areas. The geo-accumulation index (Igₑₒ) and potential ecological risk index (PERI) suggest that the sediments were polluted by combined heavy metals at minor to medium levels, posing a potential risk to ecosystem. Moreover, sediment quality guidelines (SQGs) indicate that Ni in all sites and Zn in the eastern reservoir would cause great negative biological response to benthic organisms. Additionally, the sediments were slightly polluted by N but not P, especially in the downstream. Multivariate statistical analyses revealed that Cu, Zn, Pb, and N mainly derived from industrial wastewater, domestic sewage and surface runoff from the Yangtze River, while Cr, Ni, and P mainly originated from natural erosion and nonpoint sources. Graphical Abstract .

CH₄ flux measured by a portable chamber using an infrared analyzer was compared with the flux by static chamber measurement for CW at 13 different sites from May 2012 to May 2017 in the Living Water Garden (LWG) in Chengdu, Sichuan Province, China, over 4 timescales (daily, monthly, seasonal, and annual). During the measurement period, a total of 1443 data were collected. CH₄ fluxes were measured using the portable chamber method and the results showed that the annual mean and median CH₄ flux values in the LWG were 17.4 mg m⁻² h⁻¹ and 6.2 mg m⁻² h⁻¹, respectively, ranging from − 19.7 to 98.0 mg m⁻² h⁻¹. Cumulative CH₄ emissions for LWG ranged from − 0.17 to 0.86 kg m⁻² year⁻¹. Global warming potential (GWP, 25.7 kg CO₂ₑq m⁻² year⁻¹) was at a high level, which means that the LWG was a source of CH₄ emissions. Significant temporal variations on the 4 timescales were observed. And the asymmetry of measurement uncertainty of CH₄ flux increases with the timescale. Although the total mean CH₄ flux measured by the portable chamber method was 42.1% lower than that of the static chamber method, the temporal variation trends of CH₄ flux were similar. The uncertainty of CH₄ flux measured in portable chamber was more symmetrical than that in static chamber. These results suggest that the portable chamber method has considerable value as a long-term measurement method for CH₄ flux temporal variations.

Research on pollution caused by gadolinium (Gd) based on compounds as a result of its use in high technological applications, especially in the health sector, has recently become very interesting. This study aims to investigate the determination of the environmental pollution levels of anthropogenic Gd and its possibility of use as an anthropogenic pollutant indicator in the Ankara Stream (Turkey) selected as the pilot stream. Within the scope of the research, Gd levels were determined in water and sediment samples taken in spring and autumn periods in a total of seven different stations, three of which in Ankara Stream and one for each in its tributaries (Çubuk Stream, Hatip Stream, İncesu Creek, Ova Stream). Some parameters related to water and sediment quality were also measured at the stations. Temperature, pH, electrical conductivity, and dissolved oxygen were measured in situ. Gd concentrations were measured by inductively coupled plasma mass spectrometry (ICP-MS) technique using samples filtered from 0.45-μm filters at the time of sampling in water samples. The grain sizes of sediment samples were carried out by conventional wet sieve analysis. Gd levels were determined by ICP-MS after digestion of sediment samples passing through 63-μm particle grain size. Also, total organic carbon (TOC) and total phosphorus (TP) levels were measured by classical methods in sediment samples. Although the Gd concentrations measured in the water samples taken from the stations in the Ankara Stream were found to be quite high compared with the tributaries of Ankara Stream. The highest mean Gd concentration (0.347 ± 0.057 μg/L) measured in this study was higher than that of at the most rivers in the world. There was no statistically significant difference between the stations in terms of Gd concentrations in the sediment samples. As a result of this study, it was revealed that Gd can be used as an indicator parameter in the monitoring of anthropogenic pollution of aquatic environment where potential Gd pollution sources.

Brain affection is a common symptom of liver insufficiency. This study aimed to evaluate the role of low-dose γ irradiation (LDR) as a potential therapeutic agent in thioacetamide (TAA)-induced hepatic encephalopathy (HE) in rats. Effects of local and whole-body irradiation (0.5 Gy) on rat brain/liver were evaluated following the induction of HE by TAA (200 mg/kg/day/for 3 successive days). Serum activities of aspartate transaminase (AST) and alanine transaminase (ALT) and ammonia level were assessed. The effect of HE on brain was evaluated through the determination of brain contents of malondialdehyde (MDA), reduced glutathione (GSH), tumor necrosis factor-alpha (TNF-α), and interleukin-1beta (IL-1β) and glutathione peroxidase (GPx) activity. Moreover, apoptotic and inflammatory changes in brain and liver tissues were assessed together with alpha-smooth muscle actin (α-SMA); fibrosis marker. Results showed correction of the biochemical parameters which was supported by the results of the immunohistochemical examinations. LDR is a promising hepato- and neurotherapy against HE.

Fractal geometry is widely applied in the process description of contaminant transport, but few studies quantify the complexity of contaminant plume in the time series. Although the required accuracy is outside the scope of existent characterization methods, the model of solute transport remains the most sensitive issue for researchers due to its fractal behaviour. In this paper, a synthetic model is firstly presented under the condition of homogeneous/heterogeneous aquifer with different dispersivities and numbers of continuous point leakage sources. The new Hausdorff fractal dimension for the contaminant plume in the time series is obtained by the 3D box-counting method. According to the comparison among different hydro-geologic conditions, the result shows that the complexity of the contaminant plume decreases to the constant value with the passage time when the dispersivity increases and the number of point leakage sources rises. The decreasing fractal dimension is matched with the power-exponential function. The effect resulted from the number of point sources is tended to be weak when the amount is enormous. It is showed that the number of point leakage sources does not make a noticeable distinction in the homogeneous and heterogeneous aquifers.

This study investigates the causal connection between economic growth, foreign direct investment, primary and renewable energy utilization, trade openness, and ecological footprint for 33 upper-middle-income countries (UMICs) from Africa, Asia, Europe, and America during the period from 1994 to 2017. Initially, first- as well as second-generation panel unit root tests are applied to check the integration order after confirming the cross-sectional dependency and heterogeneity. Four different tests (FMOLS, DOLS, FGLS, and AMG) are applied to estimate the long-run elasticity, whereas Dumitrescu and Hurlin (D-H) non-causality test is used to test growth, conservation, and feedback hypothesis. Results show negative relationship of economic growth on ecological footprint in Africa and Europe; renewable energy utilization in Asia, Europe, and America; and trade openness in Asia. Moreover, the results revealed an adverse impact of trade openness on ecological footprint in case of Africa and America. Furthermore, the results of D-H panel non-causality test confirm the growth hypothesis for economic growth to ecological footprint in Africa, Asia, and Europe; foreign direct investment to ecological footprint in Africa and Asia; primary energy utilization to ecological footprint in Asia; renewable energy utilization to ecological footprint in America; and trade openness to ecological footprint in Africa, Asia, and America. Furthermore, the feedback hypothesis was confirmed between economic growth and ecological footprint in Asia and Europe; foreign direct investment and ecological footprint in Africa and Asia; renewable energy utilization and ecological footprint for America; and trade openness and ecological footprint for Asia and America. Finally, in context to efficient policy implications, it is suggested to associate the economic growth with clean energy and environment-friendly technologies by expanding the share of renewable energy in America and economic growth in Africa and Europe. Furthermore, Asian policy makers need to focus on foreign direct investment and trade openness by using green energy to overcome the environmental degradation. Impulsion with these findings, the central authorities of UMICs need to focus on more investments in environmental quality not only through foreign direct investment but also exchanging their clean energy technologies through trade policies such as tax exemption, feed-in tariffs, and subsidies. Government of these countries ought to upgrade the conventional capital which will ultimately improve the human lives by providing clean environment.

A major obstacle to biodiesel commercialization is supplying feedback which increases production costs. The potential of some oleaginous yeast for conversion of waste materials to biodiesel feedstock can overcome this problem. In this study, a potential oleaginous yeast strain was used for single-cell oil (SCO) production. Two sets of experiments were designed for the optimization process. According to the results obtained from the first experiment, lipid production and lipid content of this strain increased from 1.96 g/L and 22.6% to 3.85 g/L and 35.18% by optimization of grass hydrolysis, respectively. The results of the second experiment indicate an increase in SCO production and lipid content to 7.28 g/L and 56.39%, respectively. These results were obtained when HNO₃ was used for substrate pre-treatment. Lipid analysis by gas chromatography-mass spectrometry showed a suitable and high potential of fatty acid profile for biodiesel production, which was then confirmed by evaluating the physicochemical properties of the biodiesel obtained in compliance with the US and EU standards. Consumption of microbial oil and low-cost substrate can compensate the high costs of feedstock in biodiesel production.

Restrictive requirements for maximum concentrations of metals introduced into the environment lead to search for effective methods of their removal. Chemical precipitation using hydroxides or sulfides is one of the most commonly used methods for removing metals from water and wastewater. The process is simple and inexpensive. However, during metal hydroxide precipitation, large amounts of solids are formed. As a result, metal hydroxide is getting amphoteric and it can go back into the solution. On the other hand, use of sulfides is characterized by lower solubility compared with that of metal hydroxides, so a higher degree of metal reduction can be achieved in a shorter time. Disadvantages of that process are very low solubility of metal sulfides, highly sensitive process to the dosing of the precipitation agent, and the risks of emission of toxic hydrogen sulfide. All these restrictions forced to search for new and effective precipitants. Potassium/sodium thiocarbonate (STC) and 2,4,6-trimercaptotiazine (TMT) are widely used. Dithiocarbamate (DTC) compounds are also used, e.g., sodium dimethyldithiocarbamate (SDTC), and ligands for permanent metal binding, e.g., 1,3-benzenediamidoethanethiol (BDETH₂), 2,6-pyridinediamidoethanethiol (PyDET), a pyridine-based thiol ligand (DTPY) or ligands with open chains containing many sulfur atoms, using of a tetrahedral bonding arrangement around a central metal atom. The possibility of improving the efficiency of metal precipitation is obtained by using a higher dose of precipitating agent. However, toxic byproducts are often produced. It is required that the precipitation agents not only effectively remove metal ions from the solution but also effectively bind with dyes or metal complexes.

Particulate matter (PM) is a complex mixture of particles that changes over time and from place to place; however, most PM is caused by the fuel combustion of motor vehicles and industry. PM is associated with acute and chronic illnesses, such as pulmonary and cardiovascular diseases. Medellín is one of the most polluted cities in Latin America. Therefore, the physicochemical characterization of its PM is necessary to understand its composition and effect on human health. In this study, PM was characterized by scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS) analysis, Fourier infrared spectroscopy (FTIR), inductivity-coupled plasma optical emission spectrometry (ICP-OES), and thermogravimetric analysis (TGA) in order to evaluate its morphology and chemical composition. The SEM of the PM exhibited primary particles and agglomerates. The size of the particles ranged between 0.056 and 4.5 μm. The EDS revealed elements such as carbon, silicon, calcium, lead, and iron. Furthermore, carbon monoxide, carbon dioxide, and carbonyl and aliphatic functional groups were observed by means of FTIR. Additionally, weight losses associated with volatile matter and elemental carbon were identified in the TGA analysis. The TGA and FTIR confirmed the presence of fuel and lubricant traces. Subsequently, lead was selected among the most common components in the PM in order to conduct an in silico study into its effect on ventricular activity. Lead showed a pro-arrhythmic effect by shortening the duration of the action potential under normal electrophysiological conditions, which could be associated with cardiovascular diseases.

China’s economy in the past 10 years has developed rapidly and achieved great success, but at the same time, environmental problems have been deteriorating, seriously hindering the country’s regional sustainable development. This paper proposes a common-weights DEA model based on “the priority of choosing common weights” to assess the environmental performance of 30 provinces from 2006 to 2015 and analyzes regional development in combination with China’s economic division. This paper also introduces the biennial Malmquist Productivity Index (BMPI) to study environmental productivity levels during the 11th and 12th Five Year Plans (FYP) from a time series perspective. The results present a large gap in regional environmental efficiency, mainly manifested by the fact that the eastern and northeastern regions’ environmental condition is obviously better than that of the central and western regions. BMPI analysis indicates that the overall environmental performances during the 11th and 12th FYPs did not improve significantly, with a clear imbalance in the western region, implying that its development potential is huge. On this basis, we offer some suggestions for improving the environmental performance of different regions.