China Daily (Hong Kong)

Contaminan­ts to cross Pacific Ocean

- By ZHANG ZHOUXIANG zhangzhoux­

The peak of radioactiv­e nuclear wastewater Japan plans to dump would reach the middle of the Pacific Ocean within two years of its release and eventually approach the west coast of the United States, a German study found.

Erik Behrens, a research fellow at the Helmholtz Center for Ocean Research in Kiel, Germany, copublishe­d an essay in 2012 with his colleagues on Environmen­tal Research Letters, which is also shared for open access online.

In that report, they calculated the long-term dispersion of radioactiv­e material by ocean currents once the material from the Fukushima Daiichi nuclear power plant enters the ocean.

In their simulation, they used a slowly decaying tracer with a halflife of 30 years, similar to Cesium137. The tracer was continuous­ly injected into the coastal water for weeks and they “measured” the tracer cloud day after day.

In all three models, the material moved east from Fukushima and soon spread to major parts of the eastern Pacific Ocean. The radioactiv­ity was also detected in an increasing­ly bigger area.

In about six months, the tracer cloud crossed the internatio­nal date line and reached the Western Hemisphere, the modeling showed. More importantl­y, the peak of radioactiv­ity, where the density of the tracer cloud was highest, showed an obvious trend of moving eastward after that and crossed the internatio­nal date line another six months later.

Peak center

In about two years, the center of the peak of radioactiv­ity moved to about 160°W, 30°N. By then, according to the simulation, the density of tracer cloud was already quite low in Japan, about one thousandth that of the peak.

In it abstract, the paper drew the prediction for a longer period: “By then (After two-three years) the tracer cloud has penetrated to depths of more than 400 m, spanning the western and central North Pacific between 25°N and 55°N, leading to a rapid dilution of concentrat­ions. The rate of dilution declines in the following years, while the main tracer patch propagates eastward across the Pacific Ocean, reaching the coastal waters of North America after about 5-6 years.”

The paper studied Cesium-137 only. There is also deuterohyd­rogen and Carbon-14 contained in the Fukushima nuclear waste water.

On Monday, the US Department of State said in a statement that Japan has been “transparen­t about its decision”, while US Secretary of State Antony Blinken thanked Japan via his personal Twitter account.

By far, the US is the only known major country that openly expressed its support for Japan’s move.

 ??  ?? South Koreans make clear their health concerns over Japan’s wastewater decision in a protest outside the Japanese embassy in Seoul on Tuesday.
South Koreans make clear their health concerns over Japan’s wastewater decision in a protest outside the Japanese embassy in Seoul on Tuesday.

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