The Environment Ministry has given water utility companies until the end of September to report back on organic fluorine compounds in tap water that pose a hazard to a human health.

An expert panel will decide if stricter criteria are needed for perfluoroalkyl and polyfluoroalkyl substances, chemical compounds considered to be carcinogenic that are collectively known as PFAS.

A key issue is whether to make it mandatory for local governments and other parties to take immediate steps when readings are found to be too high.

The committee aims to reach a conclusion by the end of the fiscal year after taking into account the findings of a nationwide survey on the quality of piped water that is now in progress.

PFAS refer to more than 10,000 kinds of organic fluorine compounds, the most noteworthy of which are perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA).

They are sometimes referred to as “forever chemicals” because they don’t break down easily.

The government maintains a tentative target of keeping PFAS levels in tap water at 50 nanograms or lower per liter. The same level applies to rivers and underground channels. One nanogram is one-billionth of a gram.

SITUATION OVERSEAS

Japan introduced the target values in line with standards used overseas. But in recent years, some nations have moved to further tighten their standards.

In the United States, for example, the Biden administration in April dramatically lowered the total advisory value for PFOS and PFOA. The ceiling for PFOS and PFOA went from 70 nanograms per liter to 4 nanograms per liter.

It mandated that action be taken if readings are found to be higher than the new level.

In June, the Japanese Cabinet Office’s Food Safety Commission compiled what it said is a permissible daily intake of PFOS and PFOA.

It stated that consuming up to 20 nanograms per kilogram of body weight of both PFOS and PFOA poses no health hazard even if taken continuously over a lifetime.

Given the upper ingestion limit released by the Food Safety Commission, the security standard for PFOS and PFOA in tap water should remain at 50 nanograms per liter. This estimated limit is consistent with the present tentative target.

For that reason, there may be no revision to the numerical goal.

BINDING STANDARDS

The status of the provisional target remains open to debate.

Even if PFAS readings exceed the ceiling, that does not mean local governments and other entities responsible for water supply systems are legally obliged to take steps right away.

By upgrading standards like those for mercury and arsenic, it will become compulsory for water utilities to monitor liquid quality and respond to concentrations higher than the maximum tolerable value.

During a July 17 meeting, a member of the ministry expert panel argued that it is “ideal for a formal limit to be incorporated as soon as possible, so that appropriate countermeasures can be implemented.”

It was also pointed out that as some water suppliers and survey agencies are still not ready to look into PFAS levels, it will take time for them to take action.

The Environment Ministry issued a notice demanding that local governments and water companies research and report on PFAS contamination at 12,000 locations nationwide by the end of September.

Readings topped the temporary target value in Kuwana, Mie Prefecture, and Kibi-Chuo, Okayama Prefecture, among 1,247 locations across Japan in fiscal 2021, according to the Japan Water Works Association.

In addition, studies by local governments found that the provisional limit at a water source in Chatan, Okinawa Prefecture, was higher than the provisional limit.

This raised the possibility that firefighting foam containing PFAS that is used at U.S. military bases may have polluted the water supply on Okinawa’s main island.

Yoshihiko Matsui, professor emeritus of environmental risk engineering at Hokkaido University, emphasized the significance of upgrading the target volume’s status.

“The same value can have a different meaning if it imposes a certain obligation as a water quality standard,” he said. “This would put the onus on local governments to take a thorough approach. In cases when it is difficult for them to do something alone, the state would need to extend some form of assistance to them as well.”