Investigation And Study On Pollution Caused By Large-scale Pig Breeding In Hong’an County

In recent years,Hong’an county adheres to the road of ecological breeding and puts forward the concept of innovative green and sustainable development.Through preliminary investigation and analysis,the pollution of large-scale pig breeding wastes has become a major problem restricted the development of ecological breeding in Hong’an county.On the basis of a large number of relevant investigations,this paper briefly summarized the development status of large-scale pig breeding pollution prevention and control measures at the county,and took Hong’an county as an example to investigate the pig breeding pollution and its prevention and control countermeasures.According to the statistics of large-scale pig manure breeding from 2016 to 2018 in Hong’an county,it is·estimated that the average annual output of pig manure pollutants in large-scale pig manure breeding in Hong’an county in the past three years was as follows:117000 tons of pig manure,193100 tons of pig urine,7823 tons of COD,7638 tons of BOD₅,605 tons of ammonia nitrogen,500 tons of total phosphorus,and 1326 tons of total nitrogen.The annual load of pig manure is relatively low in Hong’an county,which has little impact on the soil.According to the estimation of large-scale pig breeding capacity in 2020,there is still a large breeding capacity in Hong’an region,which can add 385600 pigs.In this study,the concentration of heavy metals and antibiotics in pig manure and feedstuffs in Hong’an county were monitored.The results showed that the content of heavy metals Cu in pig manure was 136.93 and 140.91mg·kg^-1,respectively,the content in feedstuffs was 3 to 4 times higher than the standard.Other heavy metal Zn,Pb,Cd and Cr in pig manure and feedstuffs has not overweight resist aureomycin and tetracycline antibiotics in pig manure and feedstuffs samples were detected,including aureomycin content in pig manure A₁and A₂,and in the feedstuffs B₁ and B₂ were 5.35,5.76and 14.3,17.1 mg·kg^-1,tetracycline content in pig manure A₁and A₂ and in the feedstuffs B₁and B₂were 0.11,0.26,0.33 and 0.49 mg·kg^-1.This study also detected 17 kinds of resistance genes（tetA,tetO,tetM,tetS,tetW,tetX,tetG,sul1,sul2,sul3,ermB,ermF,mefA/E,ereA,qnrA,qnrB,qnrS）and2 kind of integrated genes（intI1 and intI2）that cause resistance transmission in five samples of pig manure,field soil affected by pig manure and forest soil not affected by pig manure by real-time fluorescent quantitative PCR.Using 16SrRNA as internal genes,it was found that the resistance genes of tetO,tetM,tetW,tetX,erm B,erm F and mef A/E were high.Meanwhile,the element resistance genes in the slurry will significantly influence on the composition and distribution of farmland soil.The integration factors intI1 and intI2 in pig manure A₂samples were both detected,and there was a risk of the spread of resistance genes to the surrounding environment.According to the pollution situation of large-scale pig breeding in Hong’an region,formulate pollution prevention and control measures should be taken in accordance with local conditions and scientifically coordinate,make good use of pig breeding waste,and promote the development of large-scale pig breeding industry in Hong’an region towards environment-friendly ecological agriculture.