Determination Of Antibiotics In Manure And Their Degradation During Manure Composting

Sulfonamides(SAs)and Tetracyclines(TCs)have been widely used in animal husbandry to prevent and remedy animal diseases because of their wide-spectrum and strong antibiotic activity.Most of the antibiotic can't be completely absorbed,about60%-90% of them are released in the form of the original or primary metabolites and enter the environment through animal excreta.Some antibiotics come into the sewage plant with the aquaculture wastewater,but the removal rate in sewage treatment plants is not high,resulting in antibiotics entering surface water and groundwater through leaching and surface runoff and causing various kinds of poison to aquatic organisms,antibiotic pollution in rivers,and threatening human drinking water.Others are as the organic fertilizer into farmland,causing the antibiotics pollution in the soil,the destruction of soil microbial community structure and function,and the crops accumulation.Through the food chain transmission,It will threat to human health ultimately.In this paper,aiming at the residues of SAs and TCs in livestock and poultry manure,the contents of SAs and TCs in large-scale farms in different areas of Zhejiang province were analyzed.In addition,the law of antibiotic degradation and influencing factors were studied in the process of anaerobic composting of livestock and poultry waste?The main conclusion are as follows:(1)The methods to detect SAs and TCs by high performance liquid chromatography(HPLC)in animal wastes were optimized:the recoveries of SAs were 66.3%-78.5%and the MQL of SAs were 0.01-0.03 mg/kg;the recoveries of TCs were 71.4%-81.2%and the MQL of TCs were 0.01-0.28mg/kg.(2)The contents of seven typical heavy metals including cadmium(Cd),lead(Pb),arsenic(As),nickel(Ni),chromium(Cr),zinc(Zn)and copper(Cu)in swine manure samples from 6 large-scale farms in Hangzhou,Ningbo,Jinhua,Wenzhou,Taizhou and Huzhou in Zhejiang province were analyzed.The results showed that the contents of heavy metals could be detected in most of the fecal samples.The contents of Zn and Cu were the highest.The highest concentrations of Zn and Cu were3204.57mg/kg and 721.244mg/kg,respectively.(3)In almost all of the swine manure samples from six large-scale farms,five kinds ofSAs and three kinds of TCs were detected.The main kinds of SAs detected were Sulfadiazine(SD),Sulfathiazole(ST),Sulfamerazine(SM1),Sulfamethazine(SM2)and Sulfamethoxazole(SMZ).TCs were Oxytetracycline(OTC),Tetracycline(TC)and Chlortetracycline(CTC).The content of antibiotics in the order of different areas in livestock farms and livestock wastes were: SAs: Jinhua > Huzhou > Wenzhou >Ningbo > Taizhou > Hangzhou;TCs: Jinhua > Ningbo > Hangzhou >Huzhou >Wenzhou > Taizhou.Among the six different regions,the levels of SAs and TCs in Jinhua were both the highest.(4)After 15 days anaerobic composting,the highest degradation rate of SAs in swine manure was up to 90%,the degradation rate of SAs was in the order of: SD > ST >SM2;the highest degradation rate of TCs in swine manure was up to 95%,the degradation rate of TCs: CTC > OTC > TC.The degradation of different antibiotics in each composting treatment group accorded with the first-order kinetic equation.During the whole composting process,moisture content and biological degradation material(BDM)were the key factors affecting the degradation of SAs,and moisture content was the main controlling factor of TCs biodegradation.