The minireview is devoted to the analysis of the influence of soil pollution with heavy metals, polyaromatic hydrocarbons (PAHs), and the polychlorinated biphenyls (PCBs) on the distribution of antibiotics resistance genes (ARGs) in soil microbiomes. It is shown that the best understanding of ARGs distribution process requires studying the influence of pollutants on this process in natural microbiocenoses. Heavy metals promote co-selection of genes determining resistance to them together with ARGs in the same mobile elements of a bacterial genome, but the majority of studies focus on agricultural soils enriched with ARGs originating from manure. Studying nonagricultural soils would clear mechanisms of ARGs transfer in natural and anthropogenically transformed environments and highlight the role of antibiotic-producing bacteria. PAHs make a considerable shift in soil microbiomes leading to an increase in the number of Actinobacteria which are the source of antibiotics formation and bear multiple ARGs. The soils polluted with PAHs can be a selective medium for bacteria resistant to antibiotics, and the level of ARGs expression is much higher. PCBs are accumulated in soils and significantly alter the specific structure of soil microbiocenoses. In such soils, representatives of the genera Acinetobacter, Pseudomonas, and Alcanivorax dominate, and the ability to degrade PCBs is connected to horizontal gene transfer (HGT) and high level of genomic plasticity. The attention is also focused on the need to study the properties of the soil having an impact on the bioavailability of pollutants and, as a result, on resistome of soil microorganisms.

The purpose of this study was to determine the heavy metal concentrations and ecological risks to farmland soils caused by atmospheric deposition adjoining five industrial steel districts in Tangshan, Hebei, China. A total of 39 topsoil samples from adjoining these plants were collected and analyzed for Pb, Zn, Cu, Cr, and As. The geo-accumulation index (Igeo) and potential ecological risk index (PERI) were calculated to assess the heavy metal pollution level in soils. The results showed that the levels of Pb and As in farmland soils adjoining all steel plants were more than the background value, with the As content being excessively high. The Cr and Cu contents of some samples were over the background values, but the Zn content was not. In all the research areas, the largest Igeo value of the heavy metals was for As, followed by Pb, and the largest monomial PERI ([Formula: see text]) was As, which showed that the pollution of As in farmland soils was significant and had considerable ecological risk. Additionally, the heavy metal sequential extraction experiments showed that Pb and Cr, which exceeded the background value, were present in about 20% of the exchangeable and carbonate-bound fractions in the soils surrounding some steel plants. This would imply the risk of these heavy metals being absorbed and accumulated by the crops. Therefore, the local government needs to control the pollution of heavy metals in the farmland soils adjoining the steel plant as soon as possible, in order to avoid possible ecological and food safety risks.

The competitive binding trends of Ni(II) and Eu(III) on montmorillonite in the absence/presence of Na-oxalate are explored by using batch sorption/desorption technique, speciation modeling, and X-ray diffraction (XRD) analysis. With a series of molar Ni:Eu ratios (i.e., 1:1, 5:1, 10:1, 1:5, and 1:10), the coexisting Ni(II) did not affect the sequestration behaviors and immobilization mechanisms of Eu(III). In contrast, the presence of Eu(III) obviously suppressed the sorption percentages of Ni(II) in the acidic pH range. Even though no obvious influence of Eu(III) on the macroscopic binding trends of Ni(II) was observed under alkaline conditions, the fraction of Ni(II) adsorbed by the inner-sphere complexation mechanism decreased and that of Ni(II) precipitation increased with rising molar Ni:Eu ratio. The coexisting Na-oxalate did not influence Eu(III) sorption, while inhibited the sorption of Ni(II). The XRD analysis indicated the potential formation of two Eu-oxalate precipitate phases (i.e., Eu₂(C₂O₄)₃·xH₂O(s)-1 and Eu₂(C₂O₄)₃·xH₂O(s)-2) at different pH values (4.0 and 6.5) and Na-oxalate concentrations (ranging from 0.5 to 5.0 mM). Interestingly, the Eu₂(C₂O₄)₃·xH₂O(s)-2 phase would be transformed into the Eu₂(C₂O₄)₃·xH₂O(s)-1 solid with the increase of Na-oxalate concentration. The research findings could provide essential data for evaluating the fate of coexistent Eu(III) and Ni(II) in the complicated aquatic environment.

The main purpose of this paper is to investigate how to optimize gasoline in order to reduce the emitted pollutants caused by combustion, while the torque and power of the engine reach the maximum capabilities. To optimize gasoline formulation, an ethanol and magnesium oxide (MgO) or cerium oxide (CeO₂) mixture was added to gasoline. This study explores the role of main variables such as type of metal nanoparticle additive, engine speed, and throttle on engine performance and exhaust gas emissions through the modeling and optimization methods. Experimental design conducted through the implementation of D-optimal design, taking into account the three main parameters. To review the efficiency of this novel fuel, it was tested by a four-stroke engine connected to a dynamometer and an analyzer, under different controlled environments: speeds of 1500, 2000, 2500, and 3000 rpm at both half and full throttle conditions. The analyzed data are the power and torque of the engine, the amount of emitted CO, CO₂, HC, and NOₓ, the octane index, and the viscosity. The analyzed data were calculated and turned into models. Applying the models to data (the optimization process), close correlation between predicted and actual outcomes was found, highlighting the validity of the work. A secondary finding is that the CeO₂ mixture used at higher speeds and throttles produces less emissions, while lower speeds and throttles using the MgO mixture produce less emissions.

The aim of this research was to determine the concentrations of cadmium, lead, mercury, and arsenic and the essential elements iron and selenium in the tissues (muscle, kidney, liver, spleen, and fat) of fallow deer (Dama dama L.) without and with supplemental selenium addition. Another aim was to determine the effect of selenium addition on the indicators of oxidative stress, namely, the levels of superoxide dismutase, glutathione peroxidase, glutathione, and vitamin E. The research was carried out with 40 fallow deer during two research periods. Supplemental feed without selenium addition was provided during the first research period, and supplemental feed with added selenium (3 mg/kg) was provided for 60 days during the second research period. The concentration of selenium in tissues was higher in the second research period than in the first research period (in kidney tissue, 0.957 vs. 0.688 mg/kg, P < 0.05). The dietary addition of selenium decreased (P < 0.05) the concentrations of some heavy metals (lead in the spleen = 0.06 vs. 0.27 mg/kg and in the fatty tissue = 0.17 vs. 0.69 mg/kg; arsenic in the muscle tissue = 0.005 vs. 0.014 mg/kg, liver = 0.003 vs. 0.009 mg/kg, spleen = 0.004 vs. 0.013 mg/kg, and fat = 0.008 vs. 0.016 mg/kg). The activity of glutathione peroxidase was significantly higher (P < 0.05) in the second research period than in the first research period (1375.36 vs. 933.23 U/L).

To identify status, source of polycyclic aromatic hydrocarbons (PAHs) in urban soils and to assess soil environmental quality in Xi’an City, China, total 45 soil samples were collected from surface layer (0–10 cm) in different functional areas. Total concentrations of 16 US EPA priority PAHs ranged from 149.9 to 5770 μg kg⁻¹, with a mean of 1246 μg kg⁻¹. High molecular weight (HMW) PAHs accounted for the majority (42.4–72.2%) of the total PAHs in the urban soils, and phenanthrene (Phe), fluorene (Flo), pyrene (Pyr), benzo(b)fluoranthene (BbF), and chrysene (Chr) were the major compounds. Concentrations of PAHs varied among different functional areas. High level of PAHs was particularly apparent in industrial zones and city road overpass, while low level was recorded in scenic spots and campus. The integration of isomer ratios, principal component analysis (PCA), and positive matrix factor (PMF) indicated that the sources of PAHs in Xi’an urban soils were mainly derived from vehicle emissions and coal combustion. Based on incremental lifetime cancer risks (ILCR) model, the urban soils from the three functional areas (industrial zone, urban road, and city road overpass) posed potential cancer risk, and the cancer risks of direct ingestion for children were apparently higher than that for adolescence and for adult, respectively. Therefore, attention should be paid to the health risk for children exposed to PAHs in the urban soils.

Nicosulfuron is a post-emergence herbicide used for weed control in maize fields (Zea mays L.). Here, the pair of nearly isogenic inbred lines SN509-R (nicosulfuron resistant) and SN509-S (nicosulfuron sensitive) was used to study the effect of nicosulfuron on growth, oxidative stress, and the activity and gene expression of antioxidant enzymes in waxy maize seedlings. Nicosulfuron treatment was applied at the five-leaf stage and water treatment was used as control. After nicosulfuron treatment, the death of SN509-S might be associated with increased oxidative stress. Compared with SN509-R, higher O₂·⁻ and H₂O₂ accumulations were observed in SN509-S, which can severely damage lipids and proteins, thus reducing membrane stability. The effects were exacerbated with extended exposure time. Both O₂·⁻ and H₂O₂ detoxification is regulated by enzymes. After nicosulfuron treatment, superoxide dismutase (SOD), catalase, ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), glutathione reductase (GR), and glutathione-S-transferase (GST) of SN509-S were significantly lower than those of SN509-R. Compared to SN509-R, ascorbate content (AA), glutathione (GSH) content, GSH to glutathione disulfide ratios, and AA to dehydroascorbate ratios significantly declined with increasing exposure time in SN509-S. Compared to SN509-S, nicosulfuron treatment increased the transcript levels of most of the APX genes except for APX1, and in contrast to Gst1, upregulated the transcription of sod9, MDHAR, DHAR, and GR genes in SN509-R. These results suggest that on a transcription level and in accordance with their responses, detoxifying enzymes play a vital role in the O₂·⁻ and H₂O₂ detoxification of maize seedlings under nicosulfuron exposure.

Dietary exposure to cadmium (Cd) in the Chinese population is currently a public health concern. China’s national standard for maximum limits (MLs) of Cd in foods needs to be assessed. The objective of this research is to estimate the impacts of different Cd MLs intakes from selected foods and food groups and to provide scientific evidence for ML establishment. Food consumption data were taken from the Chinese National Diet and Nutrition Survey. Cd contamination data were obtained from the National Food Contamination Monitoring Program. A beta binomial normal (BBN) model was applied in the probabilistic assessment. Different possible ML scenarios for rice were selected to assess the impact of different MLs on Cd concentration and intake. More than 70% of children aged 2–6 years and over 30% of the general population have a dietary daily Cd intake above provisional tolerable daily intake (PTMId). Cd intake changed greatly relative to baseline when different possible MLs were used, but the changes were not as large when compared among the different possible MLs. Cd exposure in China, especially for children, is a public health concern. It is recommended that the ML for rice be held at 0.2 mg/kg.

Forest-water reuse (FWR) systems treat municipal, industrial, and agricultural wastewaters via land application to forest soils. Previous studies have shown that both large-scale conventional wastewater treatment plants (WWTPs) and FWR systems do not completely remove many contaminants of emerging concern (CECs) before release of treated wastewater. To better characterize CECs and potential for increased implementation of FWR systems, FWR systems need to be directly compared to conventional WWTPs. In this study, both a quantitative, targeted analysis and a nontargeted analysis were utilized to better understand how CECs release to waterways from an FWR system compared to a conventional treatment system. Quantitatively, greater concentrations and total mass load of CECs was exhibited downstream of the conventional WWTP compared to the FWR. Average summed concentrations of 33 targeted CECs downstream of the conventional system were ~ 1000 ng/L and downstream of the FWR were ~ 30 ng/L. From a nontargeted chemical standpoint, more tentatively identified chemicals were present, and at a greater relative abundance, downstream of the conventional system as well. Frequently occurring contaminants included phthalates, pharmaceuticals, and industrial chemicals. These data indicate that FWR systems represent a sustainable wastewater treatment alternative and that emerging contaminant release to waterways was lower at a FWR system than a conventional WWTP.

Wind–wave disturbances frequently disperse sediment particles into overlying water, which facilitates the adsorption and desorption of contaminants in aquatic ecosystems. Tetracycline (TC) and sulfadimidine (SM2) are common antibiotics that are frequently found in aquatic environments. This study utilized microcosms, comprising sediment and water from Lake Taihu, China, to examine the adsorption and desorption of TC and SM2 under different wind–wave disturbances in a shallow lake environment. The adsorption experiments were conducted with three different concentrations (1, 5, 10 mg/L) of TC and SM2 in the overlying water, and two different (background and strong) wind–wave conditions for 72 h. Subsequently, four microcosms were employed in a 12-h desorption study. Analysis of adsorption progress showed that TC concentration in the overlying water decreased quickly, while SM2 remained almost constant. In the desorption experiments, SM2 released to the overlying water was an order of magnitude greater than TC. These results indicate that sediment particles strongly adsorb TC but weakly adsorb SM2. Compared to background conditions, the strong wind–wave conditions resulted in higher concentrations of TC and SM2 in sediment and facilitated their migration to deeper sediment during adsorption, correspondingly promoting greater release of TC and SM2 from sediment particles into the overlying water during desorption.