The town of Kibichuo in Okayama Prefecture on Monday started blood tests for residents after PFAS, which are potentially carcinogenic chemicals, were detected at a local water purification plant.

This is the first publicly funded blood tests for PFAS, or perfluoroalkyl and polyfluoroalkyl substances, in the country, according to the Environment Ministry.

About 800 residents are expected to take a blood test under the program, which runs through Dec. 8.

The tests will measure PFAS blood concentration, lipid levels, liver function, anemia and thyroid hormone, and the results will be analyzed by Okayama University and others.

The town plans to conduct follow-up tests five years later.

A concentration of PFAS equivalent to 28 times the national safety standard was detected at the water purification plant in October last year.

In September this year, a committee of outside experts said that used activated carbon left by a local company in an outdoor material storage area is believed to be the source of PFAS detected at the purification plant, a conclusion that raised health concerns among residents.

The ministry is cautious about conducting blood tests for PFAS, saying that there is not enough scientific knowledge at present on the relationship between PFAS levels in blood and health effects.

Still, the ministry plans to begin monitoring in fiscal 2025 to examine the status of exposure to chemical substances, including PFAS, in the country.