China has decided to prohibit seafood imports from ten Japanese prefectures. Furthermore, customs authorities will screen all shipments from other regions to safeguard the safety of domestic consumers, according to the country’s General Administration of Customs.

Chinese authorities don’t agree with a report from the International Atomic Energy Agency (IAEA) that has greenlighted Japan’s plans to gradually discharge water in Fukushima by saying it “will have a negligible radiological impact on people and the environment.”

“Chinese customs will continue to strengthen the detection and monitoring of radioactive substances, ensure the safety of Japanese food exported to China, and strictly prevent the import of risky products.”

“The Japanese side still has many problems in the legitimacy of sea discharge, the reliability of purification equipment and the perfection of monitoring programs.”

Overly severe measures?
China will block imports from ten prefectures, in a repeat of the import restrictions it implemented after the Fukushima nuclear catastrophe caused by a tsunami in 2011 when radioactive water leaked into the ocean without control. 

Custom authorities have also announced a “strict 100%” screening of certification documents for any edible aquatic product from Japan.

“The discharge of nuclear-contaminated water from Japan into the sea has become the focus of global attention,” they note.

China is the biggest seafood export market for Japan, worth JPY 87.1 billion in 2022 (US$608.65 million), followed by Hong Kong (US$527.59 million) and the US (US$376.65 million), according to the Ministry of Agriculture, Forestry and Fisheries of Japan.

Contaminated waters
While the discharge of new residual water might be safe, according to the IAEA, the water near Fukushima remains contaminated.

Last month the Tokyo Electric Power Company, which is in charge of the future water release, published a report showing that one fish caught in the harbor just next to the nuclear plant was over 180 times the food safety limit of radioactive cesium.

According to the Fukushima Revitalization Station, food safety authorities consider 100 becquerels of cesium per kilogram as the limit for the radioactive substance. The caught fish was found to have levels upwards of 18,000. 

Releasing the tritium
The water currently being treated in Fukushima and due to be released gradually has no cesium left. However, it still contains radioactive tritium.

The water with tritium residues will be released with a concentration of 1,500 becquerels per liter into the ocean, wher it will be dispersed naturally. To put into context, the limit of tritium in US drinking water is 740 becquerels per liter.

Some countries are less restrictive, like Canada (7,700 limit) and some have tighter restrictions, like the EU (100 limit) according to Canada’s nuclear regulator.