Predicting mass loadings of veterinary drugs discharged into surface waters in regions with active livestock farming

2020 Fiscal Year Final Research Report

• Project/Area Number: 19K20470
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 64010:Environmental load and risk assessment-related
• Research Institution: Kanazawa University
• Principal Investigator: Hanamoto Seiya 金沢大学, 環境保全センター, 講師 (10727580)
• Project Period (FY): 2019-04-01 – 2021-03-31
• Keywords: 動物用医薬品 / 畜産排水 / 河川調査 / 数理モデル / 原単位

Outline of Final Research Achievements

We developed a model for predicting annual loads of veterinary antibiotics discharged into surface waters as effluent from livestock farms, sewage treatment plants, and households. To verify the model, we monitored three antibiotics which are much used for livestock in Japan and are stable during river transport, i.e., sulfamonomethoxine (SMM), sulfamethoxazole (SMX), and lincomycin (LCM), over one year in the Oyodo River, which has the most active swine farming area in Japan in its catchment. Concentrations and mass flows of SMM and SMX showed a sharp peak in winter, and those of LCM were also higher in winter than in summer in the river. Annual mass flows observed in the river were within a range of 1/2 to 2 times the model estimates.

Free Research Field

水環境工学

Academic Significance and Societal Importance of the Research Achievements

欧米と日本では家畜糞尿の管理方式が異なっており、「欧米」では豚の糞尿は主に液肥として農地に散布されるが、「日本」では豚の糞尿は分離された後、尿は排水処理された後に水圏放流され、糞は堆肥化後に農地散布される。本研究により、排水処理と堆肥化を基幹技術とした国内の家畜糞尿管理方式において、動物用医薬品の水圏排出量の予測手法が世界で初めて提案された。他物質・他河川におけるモデルの検証・改良が必要であるものの、本研究により、動物用医薬品の流域管理において重要な知見が提供されたと考えられる。