[Nagano University Press Release] PFAS (Fluorinated Organic Compounds) Examination of Well Water at the Institute of Freshwater Biology and Found to be Below the Lower Limit (<5ng/L)

Per- and polyfluoroalkyl substances (PFAS) are persistent and long-lived in the environment and are known to pose risks to human health and the environment, leading to growing concerns about exposure at the source of contamination. Studies have shown that human effects include a weakened immune system, elevated cholesterol levels, changes in liver enzymes, a slight reduction in birth weight in infants, reduced vaccine response in children, an increased risk of high blood pressure in pregnant women, and an increased risk of kidney and testicular cancer. Currently, more than 4,700 different PFASs are used in almost every industrial sector and many consumer products, and the release of PFASs into the environment has caused large-scale contamination in many countries.

In Japan, the Ministry of Health, Labor and Welfare has identified two common PFAS chemicals, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), as targets for water quality management in tap water, setting a preliminary target of 50 ng/L for the combined level of PFOS and PFOA. In response, high levels of PFAS have been detected in rivers and well water throughout the country, including well water used for tap water in the Tama area of Tokyo. PFAS has also been detected in tap water around U.S. military bases nationwide, and it has been suggested that this is due to leakage during firefighting training at U.S. military bases. In Nagano City, it was found that the provisional target level had been exceeded in the Kawai Shinden area along the Sai River, and water extraction from some water sources is currently being stopped.

Well water used for breeding and experiments with freshwater fish at the Institute of Freshwater Biology was collected on June 20, 2023, and the concentration of PFOS and PFOA was measured (water temperature 16.7°C), resulting in a low value of less than the lower limit of 5ng/L. The provisional national target value is 50ng/L or less, making it clear that the possibility of water contamination by PFAS in the Komaki area of ​​Ueda City is low.