Detection of Antiviral Drugs Oseltamivir Phosphate and Oseltamivir Carboxylate in Neya River, Osaka, Japan

抄録

Presence of the antiviral drug oseltamivir in considerable concentrations in surface waters especially in seasonal and pandemic influenza cases has raised concerns on its possible consequences in the environment and human health. This investigation aimed to elucidate concentration levels of the drug in Neya River in Osaka during 2009/2010 seasonal influenza. Oseltamivir phosphate was detected for the first time in Neya River suggesting the presence of the drug in phosphate form in surface waters is significant only in influenza pandemic cases. Oseltamivir carboxylate concentrations in Neya River were as high as 15-fold the concentrations in Yodo River in 2007/2008 and 3-fold the concentrations in a sewage treatment plant effluent in Kyoto in 2008/2009. The highest oseltamivir carboxylate concentration in Neya River was detected at ST-2 (864.8 ng/L) followed by ST-3. This was possibly due to the inefficiency of the treatment plant upstream and low river water flowrate. Based on the limited information available on the possible environmental risks of the drug in surface waters, the detected concentrations in Neya River may not be an immediate threat to the environment. However, detailed risk assessment studies are essential to clarify the potential environmental risk issue.