PFAS chemicals detected in sewage sludge at 34 locations across Japan

The Mainichi

10 hours ago

OSAKA (Kyodo) -- Potentially harmful PFAS chemicals have been detected in sewage sludge at 34 wastewater treatment plants across Japan, with globally regulated PFOS found in nearly all of the samples, a study by a Kyoto University team showed Wednesday.
The study supports the view that the chemicals have spread nationwide. The Japanese government is promoting the use of sludge as fertilizer, but has not set guideline values for the amount of PFAS in sludge byproducts.
PFAS is a general term for a group of over 10,000 artificial chemicals that include PFOS, or perfluorooctanesulfonic acid, and PFOA, or perfluorooctanoic acid.
Known as forever chemicals because they are highly resistant to breakdown and accumulate in soil and water as environmental pollutants, PFAS are used in various products such as firefighting foam and nonstick cookware coatings.
"There is a possibility that PFOS, which is feared to pose health damage, is contained in sewage sludge in Japan in general," said Kazuyuki Oshita, associate professor at Kyoto University, who analyzed the findings.
"It is desirable that the accumulation of data will lead to the creation of a guideline in the future," Oshita said.
Various surveys in Japan have recently shown PFAS contamination in tap water and rivers and around factories, U.S. military bases, and Japan Self-Defense Forces facilities, raising concerns among the public given experts' concern over possible health risks.
In line with the Stockholm Convention on Persistent Organic Pollutants, Japan bans in principle the manufacturing and import of PFOS, PFOA as well as PFHxS, another type of PFAS.
The Kyoto University team analyzed sewage sludge at 34 treatment plants for 30 types of PFAS, including PFOS, from Hokkaido in northern Japan to Okinawa in southern Japan.
The median value for PFOS content was 5.1 nanograms per gram, while the highest was 69 nanograms. PFOS was confirmed at 33 out of 34 locations, while it had the highest concentration in 21 locations that detected PFAS chemicals.
The latest survey came as the farm ministry aims to double the usage of fertilizers derived from sewage sludge by 2030 from the 2021 level as the state seeks to increase the rate of domestically-sourced fertilizers.
"The quantity of PFAS is extremely small at an undetectable level. There is no problem using it," said a ministry official. The Ministry of Agriculture, Forestry and Fisheries released data last year based on its study of 86 samples of such fertilizers.
Abroad, regulations over PFAS are gaining traction, with the U.S. Environmental Protection Agency in January releasing a preliminary human health toxicity assessment over PFAS in sewage sludge applied as soil conditioner or fertilizer.
It said even a low concentration of the chemicals could pose a health risk to farmers and surrounding residents.
For PFOA and PFOS in tap water, the Japanese government will from next April regulate the levels. Utility operators need to improve water quality if the concentration of the chemicals is found to exceed 50 nanograms per liter.