The move has been approved by the United Nation’s nuclear
watchdog, the International Atomic Energy Agency (IAEA), but
China’s authorities have said issues remain, such as over the
“hasty” release of the safety report, reliability of the
purification equipment and the monitoring plan. Hong Kong is
seeking to protect its residents by suspending imports of food
products from prefectures near the release site.
Location
The release point is 1km off the coast of Fukushima Prefecture
in northeast Japan.
Origin of contamination
After the 2011 nuclear plant disaster, large amounts of water
were used to cool and stabilise the meltdown of three reactors.
The used water, contaminated with high levels of radioactive
material, leaked and flooded the tunnels and underground areas
of the facilities. It then came into contact with groundwater
from the surrounding hills, creating toxic water that has been
pumped out and stored in tanks.
They will run out of space in 2024. The annual cost of storage
is estimated at US$912 million.
The filtering process
The
Advanced Liquid Processing System (ALPS)
removes most of the radioactive elements, but the primary
contaminant remaining is tritium, a radioactive
isotope of hydrogen. Removing tritium from water is possible in
laboratories. But given the scale required for Fukushima, the
effort comes at an enormous cost.
What is tritium?
Tritium is a radioactive isotope of hydrogen. It is produced
naturally from interactions of cosmic rays with gases in the upper
atmosphere and is also a by-product of nuclear reactors. Water
containing tritium is routinely released from nuclear plants
around the world. Tritium is considered to be relatively harmless
because it does not emit enough energy to penetrate human skin.
But when ingested, it can raise cancer risks according to the
Canadian Nuclear Safety Commission.
Amount of Tritium naturally exists in the environment
(approximation)
In Bq (Becquerel, a unit used to measure radioactivity)
Tritium is found in a range of common consumer items because it
can be used in combination with phosphors to make materials that
are self-luminous. These items include exit signs, watch dials and
key chains.
Seafood import ban
In 2022, Hong Kong was Japan’s second-largest market for
agricultural and fisheries exports, taking in about HK$12.3
billion (US$1.6 billion) worth of goods, or 15.6 per cent of
Japan’s total exports. In 2021, Hong Kong was the largest importer
of Japan’s seafood products.
Seafood imports from Japan graphics in 2021 (Destination and
products)
The Hong Kong government has said that if the treated water is
discharged into the ocean, the city will immediately ban imports
of food items from the coastal prefectures near the Fukushima
plant and impose strict controls on other goods from the rest of
Japan. The ban could affect 10 prefectures:
Tokyo, Fukushima, Chiba, Tochigi, Ibaraki, Gunma, Miyagi,
Niigata, Nagano and Saitama.
Associate Creative Director Marcelo Duhalde
Edited by Francine Chen
Additional research and design by
Ezra Cheung, Katie Yue, Rainbow Pun
Additional web development Yan Jing Tian
Cover illustration by Marcelo Duhalde
Sources: SCMP, International Atomic Energy Agency, Ministry of the
Environment Government of Japan, Health Physics Society, Tokyo
Electric Power Company Holdings Inc, Japan Ministry of
Agriculture, Forestry and Fisheries, Canadian Nuclear Safety
Commission