A Facebook post published on June 14 claimed Hong Kong recorded higher radiation levels than in Japan’s Fukushima, a region that suffered from nuclear accidents when an earthquake and tsunami hit the area in 2011.
The post was accompanied by a screenshot taken from the Hong Kong Observatory website showing ambient gamma radiation levels in Hong Kong on the same day.
The overlaying text in Chinese reads “radiation levels exceed Fukushima’s” and the post has repeated the claim saying “[Hong Kong leader] Carrie Lam defeats Japan again; radiation levels in Hong Kong have exceeded Fukushima’s today!”
The same user also posted a screenshot showing radiation levels in Soma City in Fukushima by the Japanese Nuclear Regulation Authority and said, “I did not make a wrong accusation~ They had 0.08~ And Hong Kong had 0.12~.”
The post has been shared more than 360 times and garnered 248 reactions.
A similar claim was circulating on Twitter as well. Citing an unidentified online source, it said the radiation levels within the 150-kilometers perimeter of the Taishan nuclear plant have exceeded the “warning limit” of 0.50 microsieverts several times “last night.” This tweet has been retweeted 411 times and liked 512 times.
Both claims are misleading.
While the cited data appeared to be accurate, the radiation levels in Hong Kong remained consistent before and after the issues at Taishan power plant were reported, according to the Hong Kong Observatory quoted by the media (such as this).
Annie Lab looked at the average radiation levels in Hong Kong seven days before and three days after CNN first reported on the “possible radiation leak.”
The Observatory data shows the average radiation levels had been stable; the highest level had remained at 0.14 microsieverts per hour, which is within the Hong Kong hourly mean ambient gamma radiation dose rate of 0.06 to 0.3 microsieverts per hour.
“There is no point in comparing the ambient radiation levels between Hong Kong and Japan,” said Luk Bing Lam, the chairman of the Hong Kong Nuclear Society.
He says the radiation levels in both locations are “well within the safety limit.”
According to Luk, people in Hong Kong absorb an annual radiation dose of 0.9636 millisieverts, based on an estimated hourly dose of 0.11 microsieverts multiplied by 24 hours and 356 days.
It is much lower than the worldwide average dose of approximately 2.4 millisieverts per year. Luk also said the legal limit for persons employed in radiation work is 20 millisieverts per year.
He added that the higher radiation levels in Hong Kong were because of granite that contributes to a significant amount of the city’s annual background radiation dosage. Granitic rocks cover about 35% of Hong Kong’s land area, according to the book “Hong Kong Landscapes: Shaping the Barren Rock.”
On June 14, CNN reported that the U.S. government was assessing a report of a possible leak of radioactive gas at Taishan nuclear power plant, following a warning of an “imminent radiological threat” from the French firm Framatome in charge of the plant’s maintenance.
Two days later the Chinese National Nuclear Safety Administration said approximately five out of more than 60,000 fuel rods in the plant’s Reactor No.1 have been damaged, which is “inevitable and common,” but denied leakage has occurred. The statement cited safety limit allows damages up to 0.25% of the fuel rods, which is about 150.
On the same day, Hong Kong’s Secretary for Security John Lee Ka-chiu said the government has been in contact with Guangdong’s Nuclear Emergency Committee Office and the National Nuclear Safety Administration and was told that “the operation of the Taishan nuclear plant is safe and there is no indication of any effect on the environment.”
Luk said even in the event of leakage at the Taishan nuclear plant, nearby areas such as Hong Kong would still be safe.
“As nuclear power plants have multiple barriers, any leakage of gases from the fuel rods will be kept inside the nuclear reactor pressure vessel,” he said.
“Such gases will then be extracted, stored, diluted and filtered before being released to the atmosphere.”