Considering the low utilization rate of swine waste resources, their proper handling has become difficult during swine breeding. The development of scale swine breeding industry experiences important issues on environmental pollution (Oliveira C, 2001;Won S G, 2016). In recent years, ectopic fermentation system (EFS), as A new swine waste treatment technology, was developed for waste treatment by using a complex microbial preparation of functional thermophilic microbes mixed with straw as carrier prior to fermentation (Shen, 2021; Jiang, 2020, Yang, 2018;,Guo, 2015). Figure 1 shows the working process of EFS. After dynamic spraying, ploughing, and fermentation, the odor of raw swine waste can be effectively controlled and treated. At present, With the prevention and control of African swine fever, EFS has been developed for waste treatment in a swine farm in Zhejiang Province, and this method has the advantage of separating from the wastes core area, satisfying the requirements of biological protection and convenient maintenance (Guo, 2015; Jiang, 2020).
Antibiotics are used for livestock, and approximately 46.1% of antibiotics produced (~90,000 tons) in China every year are used in animal husbandry (Shen ,2014,;Zhang,2015). In the United States, nearly 50% of antibiotics (~22,700 tons) are used in animals and aquaculture every year (Kümmerer,2009). Van Boecke et al. conservatively estimated that the total consumption antibiotics in animal production in 2010 is 63,151 ± 1,560 tons, and the antibiotic consumption is expected to increase to 67% by 2030 (Van Boeckel,2015). Serious dependence or even overuse of antibiotics will lead to two major problems in safety, namely, antibiotic residues and bacterial resistance, which not only do harm to the sustainable development of animal husbandry, but also seriously threaten food safety, human health, and ecological environment (Ramaswamy, 2010;Hamscher, 2018).
Mattress is among the main products of EFS. In ectopic fermentation, high-temperature-resistant microorganisms are used to degrade feces and urine by aerobic fermentation (Jiang, 2020; Yang, 2018;Shen, 2019). Then, mattresses are used as organic fertilizer for agricultural soil. Antibiotics used in swine farm are mostly excreted in the form of prototypes through feces and urine (Rasschaert ,2020;Wohde, 2016). In the process of EFS, these antibiotics continuously accumulate in the mattress through the spray of feces and urine with prolonged fermentation accumulation time. If the amount exceeds the acceptable range, it may have adverse effects on the living environment of the normal soil and the horizontal transmission of drug resistance genes in the digestion area. Moreover, antibiotics in mattress have a negative effect on the microbial growth of mattress (Shen 2019). Efficient and low-cost treatment of mattress, the environmental safety of antibiotic consumption area, and the quality of mattress products can be ensured by solving the problems on antibiotic residues in matters of EFS and the safety evaluation of mattress.
Previous studies have investigated the ability of thermophiles and improve the fermentation performance in EFS (Shen, 2019;Jiang, 2020; Yang, 2018; Guo 2015). However, the research on the data of antibiotic residues in the mattress of EFS and risk assessments of mattress have not been conducted. Accordingly, the present study aimed to (1) determine the concentrations of 54 common antibiotics, including 4 tetracyclines (TCs), 19 quinolones (QNs), 22 sulfonamides (SAs), 3 amphenicols (APs), and 6 macrolides (MCs) in the mattress of Wenzhou, Lishui, and Quzhou region, Zhejiang Province; (2) analyze the occurrence and distribution of antibiotic residues in mattress of 12 typical farms at 2019; and (3) conduct risk assessments of antibiotic from mattress into absorptive soil along with the guidelines for environmental risk assessment of veterinary drugs. These results provide reliable data support for the safety problem of mattress in EFS.