Atmospheric N deposition is a serious problem in subtropical China where N is present in large amounts but P is deficient. Several studies hypothesized that N₂ fixers can overcome phosphorus limitation by trading fixed N₂ for soil phosphorus. In order to know whether N₂ fixers could invest fixed N₂ in extracellular phosphatase production and could stimulate arbuscular mycorrhizal fungi (AMF) to acquire soil P in N-rich subtropical China, an open-air greenhouse experiment was carried out. Two N₂ fixers (Acacia mangium and Ormosia pinnata) and two non-N₂ fixers (Schima superba and Pinus massoniana) were exposed to three levels of N addition: 5.6 kg ha⁻¹ a⁻¹ (ambient N), 15.6 kg ha⁻¹ a⁻¹ (middle N), and 20.6 kg ha⁻¹ a⁻¹ (high N). We found that the capacity of plants to acquire soil P in N-rich subtropical China is species specific. The higher P uptake rates were found for N₂ fixers than non-N₂ fixers under N addition, which were related to the greater soil APA and higher AMF (p < 0.01) in the soil of N₂ fixers. However, with time, high N addition decreased more significant quantities of soil microbial phospholipid fatty acids (PLFAs) in the soil of N₂ fixers than that of non-N₂ fixers (p < 0.05). We conclude that N₂ fixers have higher P uptake capacity than non-N₂ fixers under ambient N deposition in subtropical China. However, continuing N deposition in the future might affect P uptake ability of N₂ fixers as high N addition would decrease soil microbial PLFAs of N₂ fixers.

Sediment bacterial communities are sensitive to environmental fluctuations, particularly external input sources. Studying the relationships between bacterial community distribution and the estuarine environment is critical for understanding the river-lake confluence ecosystem and the effect of inflow-rivers on lakes. In the present study, bacterial communities from the sediments of 14 estuaries and four pelagic sites of the Taihu Lake were investigated via high-throughput sequencing. The results demonstrated that Delta-, Beta-, and Gamma-proteobacteria, Acidobacteria, Nitrospira, Bacilli, Anaerolineae, and Actinobacteria were the major classes in sediment bacterial communities of the Taihu Lake. In general, the inflow-rivers of different pollution types have distinctly different influences on sediment bacterial communities of the lake. The bacterial community composition and physicochemical properties of pelagic sites were closer to those of the estuaries of western region which was polluted by serious industrial and agricultural pollution. The bacterial community diversity of estuaries was lower than those of pelagic sites. Spearman correlation analysis indicated that α-diversity of the bacterial community was significantly correlated with C/N, total nitrogen, and total carbon in estuarine sediments. Redundancy analysis revealed that the variance in bacterial community composition was also significantly associated with C/N (24.9%) followed by total phosphorus (15.8%), nitrite (7.2%), and nitrate (7.7%) among different estuaries. This study provides a reference to understand the influence of inflow-rivers on the lake ecosystem, which offered a basic guidance for maintaining the ecological system and protecting the water environment of lacustrine basin.

The consumption of natural gas in Beijing has increased in the past decade due to energy structure adjustments and air pollution abatement. In this study, an integrated emission inventory of hazardous air pollutants (HAPs) emitted from gas-fired combustion in Beijing was developed for the period from 2000 to 2014 using a technology-based approach. Future emission trends were projected through 2030 based on current energy-related and emission control policies. We found that emissions of primary HAPs exhibited an increasing trend with the rapid increase in natural gas consumption. Our estimates indicated that the total emissions of NO X , particulate matter (PM)₁₀, PM₂.₅, CO, VOCs, SO₂, black carbon, Pb, Cd, Hg, As, Cr, Cu, Ni, Zn, polychlorinated dibenzo-p-dioxins and dibenzofurans, and benzo[a]pyrene from gas-fired combustion in Beijing were approximately 22,422 t, 1042 t, 781 t, 19,097 t, 653 t, 82 t, 19 t, 0.6 kg, 0.1 kg, 43 kg, 52 kg, 0.3 kg, 0.03 kg, 4.3 kg, 0.6 kg, 216 μg, and 242 g, respectively, in 2014. To mitigate the associated air pollution and health risks caused by gas-fired combustion, stricter emission standards must be established. Additionally, combustion optimization and flue gas purification system could be used for lowering NO X emissions from gas-fired combustion, and gas-fired facilities should be continuously monitored based on emission limits. Graphical abstract Spatial distribution and typical live photos of gas-fired boiler in Beijing

Optical properties and molecular composition of humic substances (HS) can provide valuable information on the sources and the history of the associated biogeochemical processes. In this study, many well-known spectral and molecular characteristics were examined in eight different HS samples, which were extracted from soils and sediments located in a forested watershed, via two advanced tools including fluorescence excitation emission matrix-parallel factor analysis (EEM-PARAFAC) and high-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Two humic-like (C1 and C2) and one protein-like (C3) components were identified from EEM-PARAFAC. Irrespective of the origins, humic acid (HA) fractions were distinguished from fulvic acid (FA) fractions by the HS characteristics of specific UV absorbance (SUVA), the number of formulas, maximum fluorescence intensities of C1 and C2, condensed aromatics, tannins, and CHON, CHOS, and CHONS classes. In contrast, only five HS indices, including C3 intensity, H%, modified aromatic index (AIₘₒd), the percentages of carbohydrates, and unsaturated hydrocarbons, were found to be significant factors in discriminating between the two HS origins (i.e., soils and sediments). The ordination of the Bray-Curtis dissimilarity matrix further confirmed that the HS chemical fraction (i.e., HA or FA) was the more important factor to determine the measured HS characteristics than the HS origin. Our results provided an in-depth insight into the chemical and structural heterogeneity of bulk HS, which could be even beyond the differences observed along the two HS origins. This study also delivers a cautious message that the two operationally defined HS chemical fractions should be carefully considered in tracking the origins of different HS samples.

To better understand the Hg(II) adsorption by some typical soils and explore the insights about the binding between Hg(II) and soils, a batch of adsorption and characteristic experiments was conducted. Results showed that Hg(II) adsorption was well fitted by the Langmuir and Freundlich. The maximum adsorption amount of cinnamon soil (2094.73 mg kg⁻¹) was nearly tenfold as much as that of saline soil (229.49 mg kg⁻¹). The specific adsorption of Hg(II) on four soil surface was confirmed by X-ray photoelectron spectroscopy (XPS) owing to the change of elemental bonding energy after adsorption. However, the specific adsorption is mainly derived from some substances in the soil. Fourier transform infrared spectroscopy (FTIR) demonstrated that multiple oxygen-containing functional groups (O–H, C=O, and C–O) were involved in the Hg(II) adsorption, and the content of oxygen functional groups determined the adsorption capacity of the soil. Meanwhile, scanning electron microscopy combined with X-ray energy dispersive spectrometer (SEM–EDS) more intuitive revealed the binding of mercury to organic matter, metal oxides, and clay minerals in the soil and fundamentally confirmed the results of XPS and FTIR to further elucidate adsorptive phenomena. The complexation with oxygen-containing functional groups and the precipitation with minerals were likely the primary mechanisms for Hg(II) adsorption on several typical soils. This study is critical in understanding the transportation of Hg(II) in different soils and discovering potential preventative measures.

Water-saving cultivation techniques have been attracting increased attention worldwide. Ridge-furrow mulching system (RFMS), as a prospective rainwater harvesting system, has been widely adopted in arid and semi-arid areas. Field experiments were conducted in 2014 and 2015 to compare soil water storage, soil temperature, maize yield, and water use efficiency (WUE) among different ridge/furrow width arrangements in RFMS comprised of three different ridge/furrow ratios, i.e., 40:70 cm (RFMS40), 55:55 cm (RFMS55), and 70:40 cm (RFMS70) and conventional flat planting (CK, without mulching). All these four planting patterns had the same planting density. The RFMS technique not only increased soil temperature of the ridge but also improved soil moisture of the furrow when compared with CK. These positive effects were intensified with increasing ridge/furrow ratio in RFMS. This improvement in RFMS resulted in more stable and earlier seedling establishment. Maize yields were increased by 26.1, 36.4, and 50.3% under RFMS40, RFMS55, and RFMS70 treatments, respectively, when compared with CK across both years. RFMS did not decrease the evapotranspiration significantly, compared with CK. Eventually, WUE were enhanced by 25.7, 38.7, and 53.9% in RFMS40, RFMS55, and RFMS70, respectively, compared with CK. Taken together, our results suggest that increasing ratio of ridge to furrow in the case of RFMS70, can be recommended as high-yielding cultivation pattern for promoting precipitation use efficiency in the rain-fed semi-arid areas.

Aflatoxin is among the natural toxins that cause serious side effects on living things. Diosmin is also one of the compounds with broad pharmacological effects. In this study, the effects on the oxidant/antioxidant system of 50 mg/kg body weight/day dose of diosmin, aflatoxin (500 μg/kg body weight/day), and combined aflatoxin (500 μg/kg body weight/day) plus diosmin (50 mg/kg body weight/day) given to the stomach via catheter female adult Wistar Albino rats is examined. Forty rats were used in the experiment, and these animals were randomly allocated to four equal groups. The test phase lasted 21 days, and blood samples and tissue (liver and kidney) samples were taken after this period was over. Some biochemical parameters (glucose, triglyceride, cholesterol, blood urea nitrogen, creatinine, uric acid, lactate dehydrogenase, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, total protein, albumin) and levels of malondialdehyde, nitric oxide, and 4-hydroxynonenal and activities of superoxide dismutase, catalase, and glutathione peroxidase were analyzed in the samples. The aflatoxin administered over the period indicated a significant increase in levels of malondialdehyde (MDA), nitric oxide (NO), and 4-hydroxynonenal (4-HNE) in all tissues and blood samples. Therewithal, the activity of antioxidant enzymes showed a change in the decreasing direction. Biochemical parameters of the group in which aflatoxin were administered alone changed unfavorably. Parallel effects were also observed in the histopathological findings of this group. The results showed that aflatoxin changed antioxidant/oxidant balance in favor of oxidant and eventually led to lipid peroxidation. Diosmin administration to aflatoxin-treated animals resulted in positive changes in antioxidant enzyme activities while the levels of MDA, NO, and 4-HNE were reduced in all tissues and blood samples examined. Diosmin alleviates the oxidative stress caused by aflatoxin. Similar improvement was observed in biochemical parameters of this group as well as in liver and kidney histopathology. No significant change was observed in the group treated with diosmin alone in terms of the parameters examined and histologic findings. As a result, diosmin may be included in compounds that can be used as a therapeutic and prophylactic agent in the event of the formation of aflatoxin exposure and poisoning in animals.

Schistosomiasis is one of the neglected tropical diseases. It is a snail-borne trematode infection, and Biomphalaria alexandrina snails are the intermediate host of Schistosoma mansoni in Egypt. The objective of this study is to evaluate the molluscicidal activity of the aqueous seed extract of Moringa oleifera against B. alexandrina snails. The results showed that this aqueous extract was lethal for B. alexandrina snails (LC₅₀ 0.27 g/l; LC₉₀ 0.41 g/l). Exposure of snails to the sublethal concentrations of this aqueous extract caused a considerable reduction in survival rates and hatchability rates of eggs of these snails. Moreover, it negatively affected some biochemical aspects, where it increased the levels of transaminases (ALT and AST), while it decreased the concentrations of total protein, albumin, and globulin concentration. Histological examinations of the digestive gland of snails exposed to the sublethal concentrations of aqueous seed extract of M. oleifera revealed severe damage in the digestive cells, where they lost their tips and some were degenerated, while the secretory cells increased in number. Regarding the hermaphrodite gland, there were losses of connective tissues and irregular sperms, and the eggs were degenerated. These findings prove the potent activity of aqueous seed extract of M. oleifera against the intermediate hosts of Schistosoma mansoni and provide a considerable scope in exploiting local indigenous resources for snails’ molluscicidal agents.

The objective of the investigation is comparative analysis of hair trace element content in workers of different departments of petrochemical plant. A total of 75 men working in office (engineers), and departments 1 (D₁), 3 (D₃), and 4 (D₄) of the petrochemical plant, as well as occupationally non-exposed persons, were examined. Hair trace element levels were analyzed using inductively coupled plasma mass spectrometry. The office workers were characterized by the highest hair As, Hg, Sn, I, and Si content as compared to the workers of other departments, whereas the level of those elements did not differ significantly from the control values. It is notable that hair Be levels in all employees of petrochemical plant were significantly lower, whereas Se content was significantly higher than that in unexposed controls. Hair toxic trace element content in workers directly involved in industrial processes did not differ significantly or was lower than that in the control group. At the same time, the highest levels of essential trace elements (Cr, Fe, and I) were observed in employees working in primary oil refining (D₁). Hair levels of Co, I, and Li were maximal in persons of sulfur and bitumen-producing division (D₄). The lowest levels of both essential and toxic trace elements in hair were detected in employees involved in production of liquefied gas, kerosene, and diesel fuel (D₃). The obtained data demonstrate that involvement in different technological processes in petrochemical complex differentially affect hair trace element content in workers.

At the European level (CEN/TC386), some efforts are currently devoted to new standards for comparing the efficiency of commercial photocatalytic material/devices in various application fields. Concerning prototype or commercial indoor photocatalytic air purifiers designed for volatile organic compounds (VOC) abatement, the methodology is based on a laboratory airtight chamber. The photocatalytic function is demonstrated by the mineralization of a mixture of five VOCs. Experimental data were obtained for four selected commercial devices and three commercial materials: drop of VOC concentration, but also identification of secondary species (with special attention to formaldehyde), mineralization rates, and Clean Air Delivery Rate (CADR). With two efficient air purifiers, these laboratory experiments were compared to the results in two experimental rooms (35–40 m³) where air pollution was introduced through wooden floor and furniture. The systems’ ageing was also studied. The safety of the commercial products was also assessed by the determination of nanoparticle release. Standardized tests are useful to rank photocatalytic air purifiers and passive materials and to discard inefficient ones. A good correlation between the standard experiments and the experimental room experiments was found, even if in the latter case, the concentration of lower weight VOCs drops less quickly than that of heavier VOCs.