"We note that Chinese citizens last week had such a commodity [salt] in their luggage... We note that there were no such goods earlier," the agency stated.
Although other checkpoints "have yet observed no increase," the day when Japan started to release water from Fukushima, Chinese online retailers reported that they had run out of salt.
Japan started dumping the treated water that had previously served to cool damaged reactors at the Fukushima Daiichi NPP on August 24.
The International Atomic Energy Agency (IAEA) confirmed the start of the discharge and said experts were on site to ensure the procedure met safety standards despite numerous voices of protest from Japanese citizens and regional neighbors.
Consequently, China slapped a ban on imports of Japanese marine products on Thursday and announced stronger customs controls for other types of Japanese products.
A Chinese newspaper confirmed that the country had seen a surge in demand for salt amid the release of radioactive water, and the country's authorities asked citizens to refrain from mass buying.
The rush to buy the household product is based on concerns about potential contamination of sea salt and rumors spreading in neighboring countries that iodised salt can help protect against radiation poisoning.
While a type of iodine, namely potassium iodide (KI), can indeed be used to block one type of radioactive material, radioactive iodine (I-131), from being absorbed by the thyroid, it is not the ordinary table salt which people eat on a daily basis. Even iodised salt contains absolutely insufficient amount of iodine to ward off radiation.
According to the Chinese Ministry of Health, the myth is absolutely false since an adult would have to consume around 3 kilograms of salt at once to protect from radiation, while the lethal dose of table salt is about 80 grams.
Tokyo said earlier in the year that it had to discharge the treated water as it urgently needed to free up space at the disabled nuclear facility. The water has been purified of all radionuclides except tritium.
In March 2011, three of the Fukushima nuclear plant's reactors melted down after the nation was struck by a magnitude 9 earthquake followed by a massive tsunami. Fukushima is considered the worst nuclear catastrophe since the Chernobyl disaster in 1986.