May 17, 2019 Ryukyu Shimpo
Okinawa City – Over six times the standard level of hexavalent chromium was detected at the construction site where Okinawa City is planning to build a 10,000 person-capacity multi-purpose arena on May 16. Hexavalent chromium is sometimes found in the ground at construction sites, as it exists in cement. However, in Okinawa it is mainly discovered coming from U.S. military bases, or as ground pollution in the remains of past U.S. bases, and some are concerned that this current case of pollution is coming from U.S. military waste.
The construction site for the arena in Yamauchi, Okinawa was used as a garbage incineration plant until 1970, when it was repurposed as a bullfighting ring run by Koza City in 1972. In 2018, the bullfighting ring was demolished to make way for the arena, and in the remains large amounts of waste material was found mixed into the soil.
On January 11 of this year, Okinawa city conducted a soil survey of the area. The survey detected 0.275 milligrams of hexavalent chromium per liter of soil, over five times the maximum normal value (0.05 milligrams). According to the survey report, the top soil areas that exceeded five times the normal value contained waste materials, indicating, “The cause [of the high values] came from waste materials such as buried cement debris and decomposing metal that contains chrome.” Okinawa City has given their stance, announcing, “It is possible that this is caused by old construction debris.”
The area around the construction site has until now contained public works such as roads and storm drains. The head of the prefectural sewage and public works departments explained, “[The origin of the contamination] is unclear, since there is no data showing the dumping of waste material.” A representative from Okinawa City said, “It is unclear where it is coming from,” and added that because there is the possibility of it leaking into underground water, where it is highly soluble, they explained, “We are preparing water tests.” Okinawa University emeritus professor Kunitoshi Sakurai noted that cleaning materials containing hexavalent chromium were used during the Vietnam War, saying, “It is hard to believe that this came from household waste. It is not impossible that the source of this was U.S. military waste.”
[Terminology] Hexavalent Chromium – A heavy metal that is highly soluble in water and a known carcinogen. During the Vietnam War, Camp Kinser (also known as the Makiminato Service Area) in Urasoe, used a cleaning agent that contained hexavalent chromium to wash things such as trailers, heavy machinery, and engines, which was discovered by Okinawa and Urasoe during a survey in 1976. It was also confirmed that the people who worked on the base had been complaining of health problems. Hexavalent chromium was also detected at the remains of Camp Kuwae in Chatan, in some places reaching 17 times the standard amount.
(English translation by T&CT and Sam Grieb)