Philippines Detects Nuclear Radiation off Coast

Researchers have detected elevated levels of iodine‑129—a long‑lived radioactive isotope and indicator of past nuclear activity—in waters west of the Philippines.

The team believes the material originated from a mix of sources, from China to as far away as Eastern Europe, before being deposited in the Yellow Sea basin and drifting south.

Newsweek contacted the Philippine Nuclear Research Institute for comment outside office hours.

Why It Matters

While iodine‑129 occurs naturally, the vast majority of what is found in the environment today is generated by nuclear fuel reprocessing, past weapons testing and major reactor accidents.

While the isotope itself is at far too low a concentration to pose a risk to public health or fisheries, it helps scientists map how radioactive pollutants move across borders and through complex ocean currents.

What To Know

An analysis of 119 surface seawater samples found iodine‑129 concentrations ranging from 6.54 to 14.8 × 10⁶ atoms per kilogram in the West Philippine Sea, according to researchers from the Philippine Nuclear Research Institute, University of the Philippines Marine Science Institute and the University of Tokyo.

The West Philippine Sea is Manila’s term for the part of the South China Sea lying within its exclusive economic zone.

Those readings are about 1.5 to 1.7 times higher than levels measured in other Philippine‑claimed waters.

Despite the elevated readings in this specific area, the study found no evidence that the isotope was being discharged directly into local waters by the scores of nuclear plants in operation across East Asia.

Instead, researchers believe the enrichment stems from a range of other activities: The reprocessing of spent reactor fuel, past nuclear weapons tests such as at China’s Lop Nor in Xinjiang and the former Soviet Union’s Semipalatinsk test site in Kazakhstan, and fallout from the 1986 Chernobyl disaster.

This contamination was likely deposited onto soils in northeastern China before being carried by rivers into the Bohai and Yellow seas, then transported south toward the West Philippine Sea by ocean currents, per the report.

The article was published this month in the Marine Pollution Bulletin. It received funding from the National Research Council of the Philippine and the Philippine Council for Agriculture, Aquatic and Natural Resources Research and Development.

What People Are Saying

The authors wrote in the report: “Our findings highlight the need for improved policies on managing transboundary radioactivity in the region and demonstrate the application of 129I as a tracer for complicated ocean circulation in the South China Sea.”

What Happens Next

It remains to be seen whether the Philippine government will respond to the study’s findings.