The vertical migration of antibiotic-resistant genes and pathogens in soil and vegetables after the application of different fertilizers.

The prevalence of bacterial resistance caused by the application of animal manure has become an important environmental issue. Herein, the vertical migration of antibiotic resistance genes (ARGs) and pathogens in soil and vegetables after the application of different fertilizers was explored. The results showed that the application of composted manure considerably enhanced the abundance of most ARGs and pathogens, especially in surface soil and pakchoi roots. Moreover, the soil ARGs increased partially from log 1.93 to log 4.65 after the application of composted manure, and six pathogens were simultaneously detected. It was observed that the increase in soil depth decreased most ARGs and pathogens by log 1.04-2.24 and 53.98 %~85.54 %, respectively. This indicated that ARGs and pathogens still existed in the deep soil (80-100 cm). Moreover, total organic carbon had a significant influence on the pathogen distribution, whereas bacterial communities primarily drove the vertical migration of ARGs rather than environmental factors. Although most of the ARG-host associations observed in the surface soil were disappeared in deep soil as revealed by network analysis, some co-occurrence pattern still occurred in deep soil, suggesting that some ARGs might be carried to deep soil by their host bacteria. These results were novel in describing the vertical migration of ARGs in the environment after the application of different fertilizers, providing ideas for curbing their migration to crops.

Influence of Temperature Change on the Change Law of Free Radicals in Coal.

This study investigates changes in the concentration and types of free radicals in the process of coal heating, first rising and then falling. Hailar lignite, Panjiang bituminous coal, and Yangquan anthracite were selected as coal test samples. The results show that the lignite's concentration of free radical changes during heating is greater than that of bituminous coal or anthracite. It clearly shows that lignite is more prone to spontaneous combustion. In the heating and cooling portion of the experiment, the concentration of free radicals during the cooling process was much more than that of free radicals at the same temperature during the heating process. These results obtained from this research study can provide a reference for the prevention and control of the spontaneous combustion of coal with changes in temperature. This study provides a theoretical basis for the prevention and control of spontaneous combustion of coal and the selection of retarding agents and methods in the process of flame retarding by testing the free radical changes of coal at different temperatures. Also, it provides a reference for preventing and controlling coal oxidation with the change in temperature, first rising and then falling.

Study on the physicochemical characteristics and dust suppression performance of new type chemical dust suppressant for copper mine pavement.

Copper mine road dust is the major source of dust in mine operations. The dust produced on the road surface is a great hazard to the workers. Aiming at the road dust of an open-pit mine, this paper conducts a physical and chemical analysis of a new type of chemical dust suppressant. It is prepared by using sodium polyacrylate as a binder, sodium carbonate as a moisture absorbent, polyethylene glycol as a water-retaining agent, and alkyl glycoside as a surfactant. Physical and chemical characteristics and dust suppression performance of dust suppressant were tested. The results show that the dust suppressant has a pH of 11.03, a viscosity of 18.5 mPa·s, and a surface tension of 28.1 mN/m. The content of heavy metal ions contained is less than the maximum concentration defined by "The norms for the integrated treatment of copper mine acidic waste water." Under the same temperature condition, the greater the humidity, the stronger the hygroscopicity. Especially when the humidity is 30%, the hygroscopic effect is contrary to water. The dust suppressant also has good anti-evaporation properties, and it could maintain a moisture content of 4% to 5% after being placed at room temperature for 10 days. Compared with water, the dust suppressant has better performance of wind erosion, water erosion, and compression resistance. Under the same conditions, the loss rate of water is 2 times that of the dust suppressant, and the pressure of the dust suppressant sample is about 3 times that of water. The dust suppressant has a much higher dust removal efficiency for all dust and respirable dust than water under the same conditions. Finally, the test results and mechanism of the dust suppression mechanism of the dust suppressant are described and analyzed, which shows that the dust suppressant studied in this paper has good performance and is suitable for road dust prevention.

Fate of antibiotic resistance genes in farmland soil applied with three different fertilizers during the growth cycle of pakchoi and after harvesting.

The increasing prevalence of antibiotic resistance genes (ARGs) in the soil environment poses a serious threat to crop safety and even public health. In this study, the fate of ARGs in the soil was investigated during the growth period of pakchoi and after harvesting with the application of different kinds of fertilizers. The result showed that increasing rate of soil ARGs during the growth period of pakchoi followed the order of composted manure > commercial fertilizer > mineral fertilizer. After harvesting, soil ARGs abundance treated with mineral fertilizer, commercial fertilizer or composted manure significantly increased by 0.63, 3.19 and 8.65 times (p < 0.05), respectively, compared with the non-fertilized soil. The ARGs abundance in the pakchoi treated with composted manure was significantly higher than that of treatments with mineral fertilizer and commercial organic fertilizer. These findings indicated the application of composted pig manure would significantly increase the pollution load of ARGs in farmland soil and plant, and also promote the proliferation of farmland ARGs. Principal component analysis suggested that bacterial communities might have a significant influence on ARGs changes during the growth period of pakchoi. Network analysis further indicated ARGs changes may be mainly related to their host bacteria (including Gammaproteobacteria, Flavobacteriia and Bacilli). The results provided a proper method and useful information on reducing transmission risk of ARGs and control the propagation of ARGs in agricultural activities.

Numerical Simulation of the Dust Production and Transportation Law of an Intermediate Mine Heap.

In view of the current serious dust generation and environmental pollution that occur during the unloading process of an intermediate mine heap, in this study, the flow field and dust migration law for an intermediate mine heap were simulated numerically. Based on the mathematical model of the flow field and dust field, a numerical simulation was used to obtain the impact airflow and dust distribution law under different unloading conditions. The effects of different factors on the impact airflow and dust were studied. It could be concluded that the maximum impact wind velocity and dust concentration increased with an increase in the unloading flow. When the heap height is 23 m, the relationship between the maximum impact wind velocity and unloading volume was v = 0.05124(M p)0.62584 and the relationship between the dust concentration and mine unloading flow was c = 7.05613(M p)0.35002. The smaller the ore particle size, the larger the impact airflow and the greater the dust concentration. The relationship between the maximum impact wind velocity and the particle size was v = 1.54000(d)-0.23786. The relationship between the dust concentration and ore particle size was c = 30.45323(d)-0.54273. The greater the maximum impact wind speed, the more the dust generated. The existence of natural wind flow will initially accelerate the speed of dust diffusion and increase the dust concentration, but with the increase in natural wind flow, the diffusion effect will gradually reduce the dust concentration. An increase in the mine heap height will cause the impact wind's speed and influence range to continuously decrease but will only have a small effect on the dust concentration.

Study on the Oxidation Kinetics and Microreactivity of Water-Immersed Coal.

Both the macroscopic reaction and microscopic characterization of water-immersed coal have been studied. The methods of thermogravimetric analysis via Fourier transform infrared spectroscopy (TG-FTIR) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) are used. The apparent activation energy of water-immersed coal was significantly lower than that of raw coal. For the same coal sample, the production of CO in water-immersed coal is significantly higher than that in raw coal. The analysis shows that after water immersion, the content of hydroxyl and aromatic hydrocarbons in the coal increases significantly and the temperature at which fat-based and oxygen-containing functional groups participate in the reaction decreases. This indicates that the functional groups are unstable after water immersion and react violently. When the immersion time is 60 days, the activation energy is the lowest, the production of CO reaches its maximum, and the variation of each functional group is most obvious.

Treatment of smouldering coal refuse piles: an application in China.

ABSTRACT Coal refuse pile fires are a serious health, safety, and environment hazard. The fires in Guoshan Coal Refuse Pile affect daily life of the local residents. Although conventional fire control methods (water injection, grouting and surface sealing) were used to control the fires, they rekindled soon after the fire-fighting engineering was quitted. Thus, effective methods need to be applied to extinguish the fires completely without reignition. In this paper, the environmental impact of the fire on the local land, water and air is illustrated by sample analysis and photos. The self-potential method, which achieves remote detection from the ground surface, is adopted to delineate the scope of the fires to give support for the efficient and economical extinguishment of them. The three-phase foam containing water, gas and loess is proposed to control and extinguish the fires. The corresponding fire-fighting system is also invented to fit the field work and put out the fires more efficiently and conveniently. The temperature monitoring result shows that the fires are extinguished successfully with no sign of reignition.

Detection, extinguishing, and monitoring of a coal fire in Xinjiang, China.

Coal fire is a global catastrophe. Xinjiang suffers the most severe coal fire in China and even in the world. Coal firefighting work has been being conducted for decades in Xinjiang. In this paper, coal fire detection, extinguishing, and monitoring approaches that were derived from coal firefighting experience are introduced in detail by taking the Fifth Fire Area (FFA) of the Heshituoluogai coal fire for instance. We first introduce the geology and fire situation in the FFA. Before developing efficient strategies to extinguish it, magnetic and self-potential methods are adopted to delineate the extent of the fire. A composite index is proposed to better indicate the fire. The comprehensive coal firefighting method is illustrated in detail, which consists of surface cooling, excavation and leveling, borehole drilling, borehole water injection and grouting, and loess backfill. The subsequent temperature and CO monitoring records show that the fire is extinguished successfully without burnback. The methodology presented here provides guidance and reference for putting out other coal fires around the world.

The development of transgenic mice for the expression of large amounts of human lysozyme in milk.

Human lysozyme (hLYZ) has important potential applications as antimicrobial medicine and food additive. To develop a robust expression vector that ensures expression of large amounts of hLYZ in milk, here a 26,267 bp chimeric mouse whey acidic protein (mWAP)::hLYZ cassette was constructed and used as a mammary gland-specific expression vector, in which a 3,010 bp genomic sequence in the 24,466 bp mWAP gene locus was substituted by a 4,811 bp genomic sequence of hLYZ, exactly from the start codon to the stop codon. Corresponding transgenic mice were generated, and enzymatically-active hLYZ was expressed at 18.4-35 g l(-1) in the milk of most transgenic mouse lines. Our transgenic mice carrying chimeric mWAP::hLYZ represent a model system for cost-effective production of hLYZ.