The Food Safety Commission of Japan released a draft report last month on the daily intake limit for PFAS, a set of fluorinated chemicals recently linked to a range of health issues such as cancer and pregnancy complications.

The report spells out the “tolerable daily intake” (TDI) of PFAS through food for the first time. It recommended a limit of 20 nanograms each of PFOA and PFOS — two of the most used PFAS compounds — per kilogram of body weight per day.

But how worried should we be about PFAS?

Here's what you need to know:

What is PFAS?

PFAS stands for per- and polyfluoroalkyl substances, and it refers to a class of at least 4,700 synthetic chemicals that possess strong carbon-fluorine bonds, although the definition of PFAS varies among institutions, with the U.S. Environmental Protection Agency identifying nearly 15,000 compounds so far.

The chemicals have been used commercially since the 1940s to make products that resist heat, oil and water. They are everywhere — contained in everything from nonstick cookware and food wrappers to stain-free carpets, water-proof shoes, clothes and cosmetics, as well as fingerprint-resistant smartphone screens and firefighting foams.

PFAS does not easily break down and remains in the body and the environment for years, and is thus called “forever chemicals.”

Is PFAS safe?

Some of the PFAS substances have been linked to health issues. According to the U.S. Agency for Toxic Substances and Disease Registry, a branch of the Department of Health and Human Services, high levels of certain PFAS chemicals may lead to an increased risk of kidney or testicular cancer, higher cholesterol levels, risk of decreased birth weights and weakened vaccine response in children. They could also cause pregnancy complications and liver enzyme changes, the agency says.

However, much is still unknown about the health risks posed by PFAS. The risks also depend on the dose or frequency of exposure, individual sensitivity and access to safe water and health care.

How might we get exposed to PFAS?

There are several ways in which someone may be exposed to PFAS. These include drinking PFAS-contaminated water, accidentally breathing contaminated soil or dust, eating food produced near places where PFAS was used or produced, or eating food packaged in material that contains PFAS.

In Japan, there is very little data on residents’ exposure to PFAS. But recently, people in Okinawa and western Tokyo have become concerned about their longtime exposure to contaminated drinking water. In such areas, PFAS chemicals are suspected to have leaked from nearby U.S. military bases where it has been confirmed that PFAS-containing fire foams had been used in the past. In June last year, a group of concerned residents in western Tokyo announced they had PFAS levels in their blood that was more than double the national average.

Aren’t they banned in Japan?

The Stockholm Convention on Persistent Organic Pollutants, an international treaty on toxic chemicals, banned PFOS in 2009 and PFOA in 2019. Japan, a signatory of the convention, has also banned its use and imports.

PFHxS, another compound in the PFAS family, was made and used widely at least from the 1980s to until around 2020 as a substitute for PFOS and PFOA — but it has since been found to be similarly toxic. The convention moved to add PFHxS to its list of banned chemicals in 2022, and in November 2023, Japan also decided to ban the use, manufacturing and import of PFHxS. The ban will come into effect in June.

How were the health risks of PFAS evaluated?

The Food Safety Commission convened a panel of 22 experts and set out to determine the extent of the health risks posed by consuming food containing the three PFAS chemicals — PFOS, PFOA and PFHxS. They found that risk assessments varied greatly among institutions worldwide.

The experts examined 257 scientific papers in detail and took a keen interest in eight areas that PFAS has been linked to, including damage to the kidney, disturbances to lipid metabolism, decreased immunity, lower infant weight and increased chances of cancer.

The panel concluded that while the chemicals had some health risks, the evidence supporting the risks was either “insufficient” or “limited.”

Based on their assessment, the experts set the “tolerable daily intake” limit of 20 ng for PFOA and PFOS each through food consumption. They did not set a limit for PFHxS, citing a lack of data and research.

How should we make sense of the 20 ng figure?

The panel says the estimated average of PFAS intake in Japan is 0.60 to 1.1 ng per kilogram of body weight per day for PFOS and 0.066 to 0.75 ng for PFOS — much lower than the TDI limit set this time. But it also cautions that data on PFAS in food is insufficient so these estimates may change if more data becomes available.

“The intake of PFOS and PFOA through meals, including drinking water, in the normal diet of the average person in this country is not likely to result in significant health effects,” the panel concluded.

“Dietary changes due to excessive concern about the risk of PFOS, PFOA, etc. may lead to new and different risks, such as nutritional under- or over-consumption,” it warned.

What are the limits of the draft report?

Currently, Japan has a provisional limit of 50 ng per liter for PFAS in drinking water.

When the health ministry decided on the provisional limit in 2020, it arrived at the value based on the TDI of 20ng/kg/day each for PFOS and PFOA. That means official PFAS limits on drinking water will likely remain unchanged in the future.

Some experts have criticized the Food Safety Commission's draft report, saying it should adopt a stricter standard to prevent harm, even when the health risks of PFAS are not fully known. They have also criticized the limited scope of the panel’s analysis, considering how some other countries are moving to regulate PFAS as a whole, and not by individual substances, as the number of PFAS chemicals continues to grow with more substitute chemicals with similar properties being developed.

What can I do to reduce my exposure?

You will likely be able to check the PFAS levels of the drinking water in your area through the municipal government’s website.

Some municipalities have recently found exceptionally high levels of PFAS in well water. For example, in February, the city of Higashihiroshima, in Hiroshima Prefecture, found that the PFAS content in well water close to the local Seno River was 300 times the provisional 50 ng limit.

While the cause of the high PFAS levels has not been found, the city has asked the central government to demand more information from the U.S. military about its use of PFAS in the Kawakami Ammunition Depot located upstream.

Using activated carbon filters can also help minimize your exposure to chemicals that may be contained in your drinking water.

Culled from Japan Times