Okinawa surveys trace PFAS spikes to 2 Marine bases

Two Chinese naval vessels sailed between Japan’s southwestern islands this week after completing training in the Western Pacific, according to Japan’s military and China’s Defense Ministry.

The Japan Maritime Self-Defense Force spotted a guided-missile destroyer and a frigate south of Hateruma Island at about 3 a.m. Wednesday, according to a Joint Staff release. The ships were moving northwest.

The vessels were later seen sailing northeast between Yonaguni and Iriomote islands in Okinawa prefecture, entering Japan’s contiguous zone and heading toward the East China Sea, the release said.

The same vessels were also tracked Sunday sailing northwest between Amami Oshima and Yokoate Island in Kagoshima prefecture, according to the Joint Staff. The destroyer JS Akebono, assigned to a Sasebo-based surface squadron, monitored the transit.

The movements came as naval activity increased in nearby waters.

China’s aircraft carrier Liaoning sailed through the Taiwan Strait on Monday, according to Taiwan’s Defense Ministry. It was the first such transit since China’s newest carrier, Fujian, made a similar passage in December.

Japan has also increased its activity in the area. The guided-missile destroyer JS Ikazuchi transited the Taiwan Strait on April 17, the fourth such passage by Japan’s navy since June, according to Japanese media reports.

Chinese Foreign Ministry spokesman Guo Jiakun called that transit a “dangerous plot of some in Japan to militarily intervene in the Taiwan Strait and undermine peace and stability there,” according to a government transcript.

China has increasingly used waterways near Japan’s southwestern islands to travel between the Pacific Ocean and the East China Sea.

In September 2024, the Liaoning became the first Chinese aircraft carrier to pass between Yonaguni and Iriomote. That transit, along with a separate incursion by a Chinese survey vessel into Japanese territorial waters near Kagoshima, prompted Tokyo to lodge “strong protests” with Beijing.

The number of Japanese babies born in Tokyo from January through November 2025 rose 0.7% from a year earlier to 77,375, and the total for the year is expected to exceed 2024.

If confirmed, it would be the first annual increase in Japanese births in the city in 10 years.

Tokyo Gov. Yuriko Koike also said the number of marriages was expected to increase significantly for a second straight year.

Koike credited policies introduced by her administration. “The Tokyo metropolitan government has been working to provide seamless support so that people who wish to marry and have children can take those first steps with peace of mind.”

The total number of births for all of 2025 is expected to be announced in early June.

Okinawa Prefecture’s latest groundwater survey said Marine Corps Air Station Futenma was the likely source of per- and polyfluoroalkyl substances, or PFAS, found at levels up to 3,000 parts per trillion, or 60 times Japan’s water quality standard.

The division also released results Monday from a survey around Marine Corps Camp Kinser, where elevated PFAS levels were found at two sites downstream of the base.

Japan’s water quality standard for PFAS is 50 parts per trillion. The U.S. Environmental Protection Agency sets no safe minimum standard for the compounds.

The highest PFAS level, 3,000 parts per trillion, was measured at Ijunga, an underground spring downstream of Futenma. A division spokeswoman said Wednesday that the site was one of 12 sampled in December for the first time since testing began in 2021.

The second-highest level, 2,600 parts per trillion, was found at Kanjaga, another underground spring downstream of the airfield.

Around Camp Kinser, the survey recorded a maximum PFAS level of 400 parts per trillion at a drainage outlet at Irijima 3-chome in January 2025. The same outlet measured 170 parts per trillion in September, and a base stormwater drainage connection point measured 310 parts per trillion.

The prefecture surveyed those sites after 170 parts per trillion was detected at the Irijima outlet during a 2024 islandwide survey.

PFAS are used in waterproof and nonstick coatings, and in fire suppressants such as aqueous film-forming foams. They are often called “forever chemicals” because they persist in the environment. The American Cancer Society has linked PFAS exposure to an increased risk of tumors in the liver, breasts, testicles, and pancreas.

U.S. Forces Japan said in 2024 that it had incinerated its remaining stockpiles of firefighting foam containing PFAS. In an unsigned statement emailed Wednesday, it said PFAS was a “shared concern” tied to military and civilian industrial activities across Japan and that it continued to comply with agreements and procedures with the Japanese government.

The prefecture set up an expert committee in 2021 after annual island-wide surveys beginning in 2016 found high PFAS concentrations near Futenma. Because of those findings, “it is considered highly probable that the base is the source of the contamination,” the survey said.

The prefecture said it would continue monitoring groundwater around Futenma, investigate contamination in an underground basin near a firefighting training facility, and seek information through the Okinawa Defense Bureau about PFAS storage at Kinser.

The prefecture has sought access to U.S. bases for water sampling four times since 2016. U.S. Forces Japan denied the requests in December, saying evidence that its facilities were contamination sources was insufficient.