Photo/Illutration The Akashigawa river intake facility in Kobe, where Akashi city extracts water for processing and insertion into the supply network (Naoki Okubo)

A panel of experts at the Environment Ministry is discussing changes to Japan's drinking water standards to protect the public from harmful per- and polyfluoroalkyl substances, better known as PFAS synthetic chemicals.

There is growing concern about PFAS substances, which have been detected in drinking water around the nation. The overall picture remains unclear.

Therefore, the ministry must assess the situation, disclose its findings and create a safe system without delay.

PFAS chemicals repel water and oil and can withstand high heat. They are found in a range of products, including fire-extinguishing foams and semiconductors, and are also used in waterproofing processing and in the manufacturing of automobiles.

Because they hardly ever break down in nature, they can bioaccumulate, building up in bodies without being excreted.

In Japan, massive volumes of PFAS chemicals have leaked from firefighting installations at U.S. military bases in Okinawa Prefecture. They were also detected after release from U.S. bases in Tokyo and Kanagawa Prefecture and from factories.

In fiscal 2021, a survey of groundwater at 1,133 sites found PFAS levels that exceeded the provisional target at 81 locations in 13 prefectures.

Since then, PFAS substances have also been detected in a river that supplies water to the city of Akashi in Hyogo Prefecture and in mineral water produced by a Kobe-based firm.

In late May, the Environment Ministry and the land ministry directed water utilities to report on PFAS levels at about 12,000 sites around the nation. They must report their findings by the end of September.

The ministries need to identify the state of pollution and disclose the results as soon as possible.

They must also continue to assess the risks to public health and gather data on the situation both in Japan and overseas. The ministries must also continue to monitor non-PFAS pollutants.

In principle, Japan bans the manufacture and import of perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), two of the more prominent PFAS.

The World Health Organization's provisional standard value of PFAS chemicals is 100 nanograms per liter of drinking water. Britain and Germany also use this standard.

But the standard in the United States, which was set in April this year, is a more stringent 4 nanograms. (A nanogram is one-billionth of a gram.)

The Japanese provisional standard, set in 2020, is 50 nanograms. Calculations based on a daily tolerable intake amount compiled by the Food Safety Commission of Japan, released last month, endorsed this figure as a safe standard for drinking water.

The Environment Ministry's panel of experts is discussing how to define the standard value and what level to set it at.

Currently, water utilities such as local governments are under no legal obligation to take countermeasures when PFAS levels exceed the provisional target value. But legal obligations will arise when the current provisional target is upgraded to a standard level.

Some panelists have called for the standard level to be set quickly, while others have pointed out that it will take time to deal with utilities and testing bodies that are not yet fully ready for the transition. Those parties obviously require support.

Moreover, the ministry must also establish guidelines on how to remove PFAS substances from water.

Excessive measures may invite confusion.

Still, because the full extent of the harmful impact of PFAS chemicals remains unknown, we hope the ministry will take precautionary measures and prevent any full-blown crisis before it can occur, so that people can feel safe about their drinking water.

--The Asahi Shimbun, July 24

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