HIROSHIMA -- Chromosome abnormalities similar to those of A-bomb survivors have been found among two North Korean defectors who lived near the Punggye-ri Nuclear Test Site in Kilju County in North Korea's North Hamgyong province, it has been learned.
The finding surfaced after experts in Hiroshima analyzed data collected by researchers in South Korea. The maximum accumulated radiation exposure faced by one of the defectors was estimated to be 394 millisieverts. It is thought that radiation from North Korea's nuclear tests is to blame. The estimate is on par with the early-stage radiation exposure of A-bomb survivors in Hiroshima at a distance around 1.6 kilometers from the hypocenter when the city was bombed on Aug. 6, 1945. In recent years an increasing number of residents near the Punggye-ri Nuclear Test Site have complained of poor health apparently resulting from nuclear weapons testing, and calls have arisen for a probe into the extent of the damage.
In July and August 2016, and in September last year, the private Seoul-based South and North Development (SAND) research institute, which works with defectors from North Korea, questioned 21 people who had resided in Kilju County. It found that many of them were complaining of common symptoms such as headaches and nausea.
In 2016, SAND asked the Korea Institute of Radiological & Medical Sciences (KIRAMS) to test the defectors, and a radiation exposure survey was subsequently conducted. It found that a woman in her 40s who escaped from North Korea in 2011, after the North's nuclear tests in 2006 and 2009, had a chromosome abnormality in the lymphocytes in her blood, similar to that resulting from exposure to radiation. The woman's estimated accumulated radiation exposure was 320 millisieverts.
Receiving assistance from KIRAMS, South Korea's Ministry of Unification conducted a separate test of 30 people from Kilju in November last year. This test found a chromosome abnormality in a man in his 40s who defected from North Korea in 2012, likewise after the nuclear tests in 2006 and 2009. The man was born and raised in an area about 20 kilometers away from the nuclear test site, and his estimated accumulated radiation exposure was 394 millisieverts. South Korean officials, however, said there was no information available to evaluate the effects of the living environment in North Korea, so it was not possible to conclusively say that the abnormalities were caused by nuclear testing.
Masaharu Hoshi, a professor emeritus at Hiroshima University and specialist in radiation biology and physics, who analyzed the data from South Korea, commented, "It's possible that people were exposed to dust and gas containing radioactive substances. We also need to check data relating to internal contamination, such as cesium levels."
Hoshi was involved in a survey around the Semipalatinsk Test Site in northeast Kazakhstan, where the Soviet Union conducted over 450 atmospheric and underground nuclear weapons tests between 1949 and 1989.
"The conditions are similar to those at Semipalatinsk, and I guess this is the first result thought to stem from North Korea's nuclear testing," he said. An accumulated radiation level of 400 millisieverts was detected in bricks in the village of Dolon, located about 110 kilometers from the Semipalatinsk nuclear testing site.
Since the possibility of radioactive substances being dispersed in the air is relatively lower for underground nuclear weapons tests compared with those conducted in the atmosphere, Hoshi commented, "There's a possibility that radioactive materials are leaking from North Korea's test site."
Choi Kyung-hui, president of the SAND institute, underscored the need to grasp the extent of the damage.
"Nuclear development is seen as problematic, but no attention was paid to the possibility of radiation exposure. Even today, there may be many people around the testing site who were exposed to radiation and are suffering," Choi said.