The National Agriculture and Food Research Organization (NARO) has conducted a comprehensive analysis of antimicrobial substance residues and their fate in treated wastewater and compost derived from domestic swine farms. This investigation holds significant importance within the framework of "One Health", as the discharge of antimicrobial substances has the potential to promote bacterial resistance in the environment, thereby contributing to antimicrobial resistance (AMR) concerns in both human and livestock populations. While there is a notable reduction in the concentrations of antimicrobial substances through wastewater treatment and composting, variations in the extent of environmental discharge are observed, influenced by the quantities used and the operational conditions of the treatment facility. This outcome sheds light on the actual discharge status of antimicrobial substances into the environment from domestic swine farms, where information was previously meagre. In addition, it assesses the potential emergence of AMR in environmental bacteria and risks to the ecosystem. This study serves as fundamental information for formulating countermeasures against the AMR issue.
Overview
The emergence of AMR, wherein previously susceptible pathogenic bacteria become resistant to antimicrobials, is a critical challenge addressed within the "One Health" framework. "One Health" is an integrated approach that aims to sustainably balance and optimize not only the health of human and animals, but also environment soundness, because they are closely linked and interdependent.
In the livestock industry, especially in the swine farming, various studies and countermeasures have been made to ensure the prudent and appropriate use of antimicrobials. On the other hand, from a "One Health" perspective, it is equally important to minimize the discharge of these substances from swine farms into the environment. Unfortunately, information regarding the current status and effective control methods is scarce.
NARO conducted a survey focused on excrement treatment processing at swine farms to comprehend the status of residual and the actual environmental discharge of antimicrobial substances. The study targeted wastewater treatment and composting, which are commonly used at domestic swine farms. The dynamics during the treatment process were also investigated. Results indicated that the concentration of antimicrobial substances in treated wastewater and compost is lower than in the excrement before treatment, indicating that treatment reduces the risk of environmental discharge. However, the degree of this risk was shown to vary depending on various factors such as the antimicrobial quantity used in swine farms and the operational conditions of treatment facilities.
This research results comprehensively clarifies the actual status of discharge of antimicrobial substances from swine farms into the environment and the dynamics during the processes of waste treatment and composting. It also provides basic information for the countermeasure development to control discharge and risks associated with AMR issues from swine farms.
Reference Publications
Watanabe, M., Guruge, K. S., Uegaki, R., Kure, K., Yamane, I., Kobayashi, S., & Akiba, M. (2023). Occurrence and the potential ecological risk of veterinary antimicrobials in swine farm wastewaters in Japan: Seasonal changes, relation to purchased quantity and after termination of oxytetracycline usage. Environment International, 173, 107812. https://doi.org/10.1016/j.envint.2023.107812
Watanabe, M., Goswami, P., Kure, K., Yamane, I., Kobayashi, S., Akiba, M., & Guruge, K. S. (2023). Characteristics of antimicrobial residues in manure composts from swine farms: Residual patterns, removal efficiencies, and relation to purchased quantities and composting methods in Japan. Journal of hazardous materials, 459, 132310. https://doi.org/10.1016/j.jhazmat.2023.132310
