Migration Law Of β-ls And β-RGs In Soil,Surface Water And Manure In Pasture

With the rapid use and production of antibiotics in China,β-lactam antibiotics(β-lactams,β-Ls)as one of the five most commonly used antibiotics in China,the production and sales rank the top of many antibiotics,it also has a pivotal position in the global pharmaceutical industry.Penicillin and cephalosporins are the most widely used β-Ls,in 2010,the use of them accounted for nearly 60%of all antibiotics,an increase of 41%compared with 2000.The extensive use of antibiotics has led to the production of more serious antibiotic resistance genes(ARGs),and the pollution of ARGs has received strong attention.β-Ls is a common antibiotic,often used as growth promoters and livestock drugs.Although β-Ls have been widely used in the livestock industry in recent years,there are few reports that comprehensively describe the migration and diffusion of β-RGs in the pathway from surface water,manure to soil.The Durbat Mongolian Autonomous Region(hereinafter referred to as Dumeng)is an administrative region where animal husbandry is the primary industry.The entire autonomous region has many large and small livestock farms.In this study,a certain livestock farm in Du Meng was selected as the research object,and the β-Ls and ARGs in the livestock farm were visually analyzed and expressed by geographic information system(GIS),and the spatial distribution of β-Ls and ARGs were explored to provide a basis for special governance.Methods:(1)20 samples of soil(10cm,50cm-depth each,5 fecal samples and 3 water samples)was colleted designed by GIS.(2)The contents of Cephalexin(CEL),Amoxicillin(AML)and Penicillin(PG),three β-Ls,were detected by high performance liquid chromatography tandem mass spectrometry.(3)8 kinds of β-RGs ampC2,ampC4,blaOXAl/blaOXA30,blaOXA10,blaPSE,blaTEM,cfxA and fox5 were analyzed by fluorescent quantitative PCR technology.(4)Pearson correlation,cluster analysis and network analysis used to explore the similarity and correlation between the relative abundances of β-Ls and ARGs.(5)ArcMap and ArcScene used to pollutants visualization analysis,which was more intuitive and accurate to present spatial distribution of P-Ls and ARGs.Results:(1)All three types of β-Ls were detected in all soil samples both two soil layers.Among them,CEL was the highest content in both 10 cm and 50 cm-deep soil layers.The detection rate of β-Ls in all soil samples tested was higher than 20%,the detection rate of CEL and AML in 50 cm deep soil reached 100%,the β-Ls content gradually increased with the soil depth.In feces,the detection rates of the three β-Ls are all higher than 20%,and the detection rates of AML and PG both reach 100%.The above three BLs were not detected in the water samples.(2)In the relative abundance detection of β-RGs,in the 10 cm deep soil layer,the relative abundance of ampC4 is the lowest,and the relative abundance of blaTEM is the highest.In the 50 cm-deep soil layer,it is roughly the same as the situation in the 10 cm-deep soil layer,where blaTEM is the highest in the soil.As the soil depth increases,the relative abundance of ARGs increases.The relative aboundance of ARGs in feces and water samples was lower than the soil samples.The average of total ARGs in 10cm-deep soil layer was higher than the resistance of 50cm deep soil layer.(3)20 soil samples was clustered into two categories,one was CEL and AML with relatively slight contamination.The other was PG,only T12,T05,T14 and T20 among the 20 samples were detected with serious contamination.(4)The 8 types of β-RGs were also divided into two categories.ampC2,blaOXAl/blaOXA30,and blaTEM were the more severely polluted categories,and blaOXA 10,blaPSE,ampC4,fox5,and cfxA were slight polluted.(5)ArcGIS software was used to analysis the spatial distribution of P-Ls and ARGs pollution in different soil layers in livestock farms.AML,CEL and PG gradually decreased from top to bottom in the vertical direction,and the pollution distribution gradually decreased from west to east in the horizontal direction.ARGs appeared upward trend with the increase of soil depth,the southeast area of its livestock farms was seriously polluted and the western regions were all lightly polluted.Conclusion:The detection rate of β-Ls in soil samples was higher than that in manure samples and water samples.The total content of β-Ls in 10 cm-deep soil was lower than that in 50 cm-deep soil.ARGs appeared the same trend.The detection rate was the highest in the soil samples,the vertical pollution gradually decreased from top to bottom,and the horizontal direction gradually increased from west to east.In the spatial distribution of total β-Ls and ARGs in different soil layers may be caused by the accumulation and superposition of the selection pressure of β-Ls on ARGs.