Photo/Illutration Professor Takashi Yorifuji from Okayama University’s graduate school of medicine briefs residents on blood test results showing high PFAS concentrations on Feb. 16 in Kibi-Chuo, Okayama Prefecture. (Kunio Ozawa)

KIBI-CHUO, Okayama Prefecture–Residents expressed concerns at a briefing here on Feb. 16 to discuss the results of tests for PFAS synthetic chemicals in tap water, which revealed high blood concentrations of the health-threatening compounds.

About 200 residents who attended were not reassured by the town's efforts.

The town has removed bags of spent activated carbon stored at a local material yard, the suspected source of the contamination, where high concentrations of PFOA, a type of PFAS, were detected in the surrounding soil.

"Although the concentrations were high in those who drank the water, it is difficult to interpret the implications for health," said Takashi Yorifuji, a professor of epidemiology and hygiene at Okayama University’s graduate school of medicine.

"PFAS are gradually eliminated from the body over time. Undergo regular health checkups and consult a doctor if you experience any health concerns," he told the audience.

The town will offer free health checkups to some affected residents, particularly those aged 75 and older.

This was not satisfactory for about 200 residents attending the briefing.

One of them, a 71-year-old man, expressed his dissatisfaction.

“I'm not convinced,” he said. “I cannot accept the explanation that the health effects are unknown, especially when the United States has established guidelines. The town government should conduct annual tests.”

Despite the alarming test results, officials refrained from explicitly linking the chemicals to health issues, which has fueled increasing concern and mistrust among residents.

The nation's first publicly funded tests for perfluoroalkyl and polyfluoroalkyl substances, collectively known as PFAS, was conducted in November and December after the cancer-causing substances were detected from the town’s water purification plant.

Concentrations of PFOA were particularly high in the blood of residents who had been drinking the contaminated water, according to Yorifuji, who analyzed the data.

The tests examined seven types of PFAS, involving 521 residents from the affected area, 188 people commuting to the area and 20 people who lived and worked outside the area.

The median PFOA blood concentration for residents in the affected water supply area was 156.3 nanograms per milliliter, compared to 3 nanograms per milliliter for residents who lived outside the area and did not drink the water.

The figure for those who commuted to the affected area and occasionally drank the water was 14.2 nanograms per milliliter.

U.S. academic institutions set a guideline of 20 nanograms per milliliter for the total concentration of seven types of PFAS, highlighting the significant risk facing the Kibi-Chuo residents.

Japan has yet to establish its own blood concentration standards for PFAS.

To give a more complete picture of the data, officials also presented average figures for the PFOA concentration in Kibi-Chuo: 171.9 nanograms per milliliter, 3.1 nanograms per milliliter and 35.2 nanograms per milliliter, respectively.

No such significant differences were observed for the other six types of PFAS.

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