我国有机肥原料及商品有机肥中四环素类抗生素的检出率及含量

  【目的】  畜禽粪便等有机肥是抗生素污染农田土壤的重要源头之一。本研究通过调查分析我国有机肥原料及商品有机肥中四环素类抗生素的检出率及含量，为有机肥的安全施用提供依据。  【方法】  在全国采集有机肥生产的主要原料和辅料样品180个及商品有机肥样品244个，进行土霉素 (OTC)、四环素 (TTC)、金霉素 (CTC) 和强力霉素 (DXC) 4种四环素类抗生素 (TCs) 的分析。  【结果】  4种抗生素的总检出率为24.29%，其中有机肥原料和商品有机肥中的检出率分别为35.00%和16.39%，商品有机肥检出率低于有机肥原料。总样品数中检出1～2种抗生素的样品占80.58%，其中商品有机肥中占92.50%，有机肥原料中占73.02%。4种TCs含量由大到小顺序为CTC (22.11 mg/kg) > OTC (2.49 mg/kg) >TTC (1.74 mg/kg) >DXC (0.71 mg/kg)，检出率由大到小顺序为OTC (14.39%) > DXC (11.08%) > CTC (8.96%) > TTC (6.13%)。有机肥原料中4种TCs的检出率由大到小顺序为猪粪 (83.33%) > 鸡粪 (66.67%) >牛粪 (30.77%) >羊粪 (24.42%)，在鸭粪、菇渣、油渣 (枯饼)、酵母渣及骨粉中也有检出，说明TCs除了在畜牧养殖业中运用普遍，目前已延伸到蘑菇种植、动物源食品业的下脚料等。羊粪中CTC、TTC及OTC含量较高，猪粪和牛粪中CTC和OTC含量较高。商品有机肥中TCs的去除率分别为OTC (77.81%) >CTC (75.02%) >TTC (72.84%) >DXC (62.80%)。内蒙古和甘肃是4种TCs检出率及含量都最高的地区。  【结论】  有机肥原料和商品有机肥4种常用四环素类抗生素的检出率分别为35.00%和16.39%，总检出率为24.29%，商品有机肥的检出率低于生产原料。抗生素在鸡粪和猪粪及其制备的商品有机肥中的检出率高于其他原料。有机肥的堆肥化过程能去除畜禽粪便原料4种TCs的62.80%～77.81%，去除率由大到小顺序为OTC >CTC>TTC>DXC。

Detection rate and concentration of tetracycline antibiotics in organic fertilizers raw materials and commercial products in China

  【Objectives】  Livestock manures from intensive farming often contain a certain amount of antibiotics, which could get into farmland when applied as fertilizers. To provide a basis for their safe recycling, we investigated the concentration of tetracycline antibiotics (TCs) in the raw materials and commercial products of organic fertilizers in China.  【Methods】  180 samples of organic fertilizer raw materials (including auxiliary materials) and 244 samples of commercial organic fertilizer products were collected nationwide for the analysis of oxytetracycline (OTC), tetracycline (TTC), chlortetracycline (CTC), and doxycycline (DXC). The commercial organic fertilizer products only included those made from livestock manure.  【Results】  The total detection rate of the four TCs in all the samples was 24.29%, and 35.00% in raw materials and 16.39% in the commercial products, with the rate being lower in the latter than in raw materials. Detection rate of one or two types of antibiotics in total samples was 80.58%, 92.50% in the commercial products and 73.02% in raw materials. The detected concentration of the 4 TCs was in the order of CTC (22.11 mg/kg) > OTC (2.49 mg/kg) > TTC (1.74 mg/kg) > DXC (0.71 mg/kg), and the detection rate was in the order of OTC (14.39%) > DXC (11.08%) > CTC (8.96%) > TTC (6.13%). The detection rate of the four TCs in raw materials was pig manure (83.33%) > chicken dung (66.67%) > cow dung (30.77%) > sheep dung (24.42%). Residues, including oil residues (dry cakes), yeast residues and bone meal were also detected, indicating that TCs were not only widely used in animal husbandry but also had been extended to mushroom cultivation and leftovers from the animal-derived food industry. The contents of CTC, TTC and OTC in sheep dung were higher, and those of CTC and OTC in pig manure were higher. The removal rates of TCs in commercial products were in the order OTC (77.81%) > CTC (75.02%) > TTC (72.84%) > DXC (62.80%). Inner Mongolia and Gansu were the regions with the highest detection rate and concentration of the 4 TCs investigated.  【Conclusions】  The composting process of organic fertilizer generally removes 62.80%?77.81% of the four kinds of TCs in organic fertilizer raw materials, and the order of removal rate is OTC>CTC>TTC>DXC. At present, the detection rate of the four TCs in all the raw-materials and commercial organic fertilizer products is 24.29%, and that in commercial organic fertilizer products (16.39%) is lower than in raw materials (35.00%).