Shale gas flowback fluid (SGF) is generated during shale gas extraction and typically contains a variety of toxic and refractory organic compounds. In this work, a microwave-activated persulfate process (MW-PS process) was developed to pretreat SGF. The major factors influencing the treatment efficiency of the MW-PS process (PS dose, initial pH, MW power, and reaction time) were optimized, and the synergetic effect (SE), degradation of recalcitrant matter, and energy consumption were systematically investigated. Results showed that the SE of the process reached a high index (i.e., 9.85), suggesting a significant synergetic effect of MW and PS. In addition, under the optimal MW-PS condition (PS dose of 2.5 g/L, MW power of 900 W, and initial pH of 2), chemical oxygen demand removal reached 66.40% in a short reaction time of 10 min. Other analyses demonstrated that benzene series compounds, organic acids, lipid substances, alkanes, antioxidants, and fluorescent dissolved organic matter in SGF were decomposed to smaller-molecule organic matter, suggesting that refractory and toxic organic matter was removed by the MW-PS treatment process. Overall, the results of this study showed that MW-PS technology is an effective and promising method to treat SGF once the operation parameters are optimized.

Soil contamination with heavy metals is a global issue confronting the environmental pollution and human/animal health. Much work has been done on physiological and antioxidant responses of wheat in hydroponic experiments and health risks from individual heavy metal contamination to human, but limited information is available on their combined application in soil. Therefore, this pot study delineates the uptake of lead and cadmium, as well as physiological responses of wheat and associated health risks under different levels of alone and combined Cd and Pb treatments. Metal uptake increased with their increasing applied levels. The highest Cd (4.24, 1.38, and 0.92 mg kg⁻¹) and Pb (763.33, 39.63, and 16.35 mg kg⁻¹) concentrations in root, shoot, and grain, respectively, were observed at highest applied levels (0.4 mM Cd and 10 mM Pb). Furthermore, all the treatments increased lipid peroxidation and activities of superoxide dismutase, catalase, ascorbate peroxidase, and peroxidase, while decreased total chlorophyll contents and membrane stability index. Under combined application of Cd and Pb, the toxicity and detoxification responses of wheat increased compared to alone treatments. Multivariate analysis further confirmed the toxicity and accumulation pattern of metals under alone and combined treatments. Target hazard quotient values of Cd and Pb were < 1 under alone and combined treatments. The health hazard index values of Pb (97.07 and 87.89%) were higher than those of Cd (2.93 and 12.10%) in combined application for human and buffalo, respectively. This study highlights that the multi-metal contamination (Cd and Pb) is detrimental for wheat growth and human/animal health.

The use of industrial effluents for agricultural practices due to waste management properties, water scarcity, or cultural belief affects both the physiology and morphology of cultivated crops. This study reports the investigation of the agro-potentiality of the effluents from a beverage bottling company on cowpea (Vigna unguiculata) under a controlled environment. This greenhouse experiment was carried out within Obafemi Awolowo University. The effluents were applied at 0, 10, 20, 30, 40, and 50% concentrations using untreated (A) and treated (B) effluents separately in two groups. Physicochemical properties of the effluents were determined using standard methods. Exchangeable cations present in the effluents were investigated via the ammonium acetate exchange way. Morphological and yield parameters were measured in ten replicates. Transverse sections of the leaf, petiole, and stem were also investigated under a light microscopy. General linear model was used for statistical analysis with means compared using Tukey’s HSD test at p < 0.05. The effluents had pH, electrical conductivity, and total dissolved solids in the range of 7.4–7.5, 599.0–693.0 μS/cm, and 395.0–455.0 mg/l, respectively. The exchangeable calcium and potassium concentrations in the effluents range 1067.00–1937.50 and 190.0–343.50 mg/l. Application of effluent A had no significant effect on number of pods per group, seeds per pod, leaf length, leaf width, and leaf area of cowpea (p > 0.05). There was a significant effect of effluent A on the number of leaves and shoot height (p < 0.05). The application of effluent B had a significant effect on the mean number of leaves and seeds per pod at higher (40–50%) concentrations (p < 0.05). Amendment with effluent B showed no significant effect on the mean shoot height, leaf length, width and area, pods per group, pod length, and girth size (p > 0.05). The frequency of guard cells was observed to decrease with increasing effluents (A and B) concentration on the abaxial epidermis. Likewise, a “black deposit” was observed in the vessels in the stem taken from group amended with effluent A at high concentrations (30–50%). No anatomical differences were observed in the petiole and leaf transverse sections of the control and amended subgroups. The untreated and treated effluents showed agro-potentiality. However, crops grown need to be monitored for the health impacts on man and animal, as risk of crop cellular disruption exist.

The use of alternative fuels or biofuel blends could be a way to reduce the environmental burden of increasing traffic. The aim of this study was to compare emissions from conventional fuels and alternative biofuels for diesel and spark-ignition engines under comparable conditions, i.e., using the World Harmonized Transient Cycle for a heavy-duty diesel engine and the Artemis CADC driving cycle for automobiles powered by gasoline and alternative fuels. Total contents of Ba, Ce, Cd, Cr, Cu, Fe, Mn, Ni, Pb, V, and Zn were determined in emissions, fuels, and lubricating oils. In addition, the bioaccessibility of metals in emissions was also assessed by extraction in water and in simulated lung fluid (Gamble’s solution). Total particulate mass emissions, expressed per kilogram of fuel, and total contents of metals were higher for the diesel engine than for spark-ignition engines. The highest metal contents in emissions from diesel and gasoline fuels were found for Fe, Zn, and Cu. Fe and Cu in emissions from diesel and spark-ignition engines declined with the addition of bio-components in fuels. However, there was no significant decrease in the contents of other metals in emissions from biofuels. The highest degrees of bioaccessibility were observed for Ba, Zn, Cd, and V in emissions from diesel and biodiesel (according to their solubility in water). On the basis of this study, the use of biodiesel (especially methylesters of rapeseed oil) can be recommended to reduce the total mass of particulate and metal emissions from diesel engines.

Rapid economic and population growth exacerbates water resource shortages and various associative ecological factors. Additionally, climate change makes it difficult to predict potential eco-environmental risks. The Government of China enacted a large-scale forestation campaign in the northwest to cope with the region’s increasingly severe eco-environmental problems. This study applied GIS software to analyze areas where water resource changes have occurred and the reasons behind water shortages. Notwithstanding fluctuations, there was a general increase in water resource trends between 1980 and 2015. On a regional scale, we observed an increasing trend for provinces with large water resources, including Xinjiang, Qinghai, and Xizang, which accounted for 84.58% of the total increases observed between 1980 and 2015. The water resource trend for the region as a whole increased exponentially with increasing rainfall and decreasing evapotranspiration. Furthermore, water consumed by artificial forests in Northwest China reached 14 billion cubic meters, which is equivalent to 5.22% of its total annual water resources. In contrast, this study determined that under natural vegetation conservation practices, water consumed would have decreased to 10.13 billion cubic meters in 2015. Accordingly, this study concluded that the Government of China should change its policy from planting more trees to protecting natural vegetation.

The most dangerous pollution sources are intensive agricultural activity and livestock farming, whose production waste has a negative impact on soil and water quality. Livestock farming is separated into two systems: indoor (pigs and poultry) and pasture-based (livestock and sheep). Numerous studies aimed at elucidating how different systems affect the environment have been performed. In Lithuania, the biggest environmental problems are caused by 24 farms with more than 5000 pigs, 21 poultry farm with more than 1000 chickens, 2179 cow-cattle farms larger than 50 places, and about 200,000 sheep. We aimed to assess the quality of surface water in the Kaunas region next to the pig and livestock farms. In 2008–2017, seven livestock agricultural companies and seven larger farmers were regarded as potential sources of pollution in the Kaunas region. Half of these sources were pig farms, and the rest were livestock farms. Locations next to potential agricultural pollution sources were chosen to monitor the surface water. The results indicated that although the agricultural areas, number of livestock units, and nitrogen rate per 1 ha were similar between the pig and livestock farms, the activity on the pig farms affected the surface water quality more than that on livestock farms. As the number of livestock units (LU) increased on the farms, the pH decreased and the suspended materials, nitrates, and phosphates increased in the surface water. With increasing nitrogen kg/ha, the pH values decreased, thereby yielding more acidic water. The intensity of agricultural activity did not affect the water quality near the livestock farms, except for livestock units (LU), which affected the pH.

Biodiesel appears to be a possible substitute for non-renewable fossil fuels; however, its production requires the presence of a catalyst to accelerate the reaction. Serving the purpose of finding effective, cheap and environmentally safe, heterogeneous catalysts, this research used the fig leaves in three different forms, calcined, activated by KOH, and activated by both K₂CO₃ and CaCO₃. Their efficiency in biodiesel synthesis, from spent cooking oil, was examined and compared with that of activated carbon which has been previously investigated. The properties of different catalyst forms were specified using X-ray diffraction, scanning electron microscope and Fourier transform infrared spectroscopy. Operating parameters studied for the three catalysts were reaction time (from 30 to 180 min), alcohol-to-oil molar ratio (from 4:1 to 10:1), catalyst loading (from 0.5 to 5% by wt.), and stirring speed (from 100 to 400 rpm). The increase in reaction time, molar ratio, and catalyst loading proved to have a favorable effect on % conversion to biodiesel but to a certain degree; increasing the stirring speed augmented the conversion. At optimum conditions (2 h of heating, 6:1 alcohol-to-oil molar ratio, 1% by wt. catalyst loading, and 400 rpm stirring), fig leaves activated by KOH provided the highest conversion to biodiesel (92.73%). The measured properties of the produced biodiesel (density, viscosity, flash point, cloud point, and pour point) yielded encouraging results. Graphical Abstract

Traditional Chinese medicine residue (TCMR) is the solid substances remaining after the extraction of pharmaceutical ingredients from medicinal plant materials, which include abundant soil nutrients. However, TCMR is nearly lost as domestic garbage, which not only occupies a large amount of land but also leads to the waste of resource, as well as causing the eco-environment potential pollution. Therefore, we implemented this study to assess whether TCMR could be used as an organic fertilizer in agricultural practices for realizing waste resource utilization, improving soil fertility, and enhancing plant growth. The results showed that (1) application of TCMR could improve soil fertility, particularly in enhancing the soil contents of SOM, TN, NaOH-N, NaHCO₃-P, and HNO₃-K; (2) the higher application ratios of TCMR (0.8–1.0%) that increased the soil EC values would cause the risk of soil secondary salinization; (3) the lower application ratios of TCMR (0.2–0.6%) has a better positive effect on improved the maize seedlings’ physiological parameters and photosynthetic performance than the higher application ratios; (4) although application of TCMR lead to the heavy metal (Cr, Pb, Cd, As, and Hg) content increased in soil, there was no ecology risk under below 0.8% application ratio, compared with the China soil risk control standards, geo-accumulation index (Igₑₒ), and pollution load index (PLI). Thus, TCMR could potentially be used as an organic fertilizer in agricultural practices. This approach is an effective strategy not only for achieving TCMR disposal but also for realizing waste resource utilization, as well as for improving soil fertility and plant growth.

Mercury exposure has been shown to affect the reproductive system in many organisms, although the molecular mechanisms are still elusive. In the present study, we exposed Drosophila melanogaster Canton-S adult females to concentrations of 0 mM, 0.1 mM, 0.3 mM, 3 mM, and 30 mM of mercury chloride (HgCl₂) for 24 h, 48 h, or 72 h to determine how mercury could affect fertility. Alkaline assays performed on dissected ovaries showed that mercury induced DNA damage that is not only dose-dependent but also time-dependent. All ovaries treated for 72 h have incorporated mercury and exhibit size reduction. Females treated with 30 mM HgCl₂, the highest dose, had atrophied ovaries and exhibited a drastic 7-fold reduction in egg laying. Confocal microscopy analysis revealed that exposure to HgCl₂ disrupts germinal and somatic cell organization in the germarium and leads to the aberrant expression of a germline-specific gene in somatic follicle cells in developing egg chambers. Together, these results highlight the potential long-term impact of mercury on germline and ovarian cells that might involve gene deregulation.

Pro-thrombotic and inflammatory changes play an important role in cardiovascular morbidity and mortality, resulting from short-term exposure to fine particulate air-pollution. Part of those effects has been attributed to the ultra-fine particles (UFPs) that pass through the lung and directly contact blood-exposed and circulating cells. Despite UFP-induced platelet activation, it is unclear whether the penetrated particles exert any direct effect on endothelial cells. While exposure levels are boosting as a result of world-wide increases in economic development and desertification, which create more air-polluted regions, as well as increase in demands for synthetic UFPs in medicine and various industries, further studies on the health effects of these particles are required. In this study, human pulmonary and cardiac microvascular endothelial cells (MECs) have been exposed to 0.1, 1, 10, and 100 μg/ml suspensions of either a natural (carbon black) or a synthetic (multi-walled carbon nano-tubes) type of UFPs, in vitro. As a result, no changes in the levels of coagulation factor VIII, Von Willebrand factor, Interleukin 8, and P-selectin measured in the cells’ supernatant were observed prior to and 6, 12, and 24 h after exposure. In parallel, the spatio-temporal effect of UFPs on cardiac MECs was evaluated by Transmission Electron Microscopy. Despite phagocytic uptake of pure UFPs observed on cellular sections of the treated cells, Weibel-Palade bodies remained intact in shape and similar in number when compared with the untreated cells. Our work shows that carbon itself is a non-toxic carrier for endothelial cells.