* Cumulative radiation from Japan is one-tenth of Chernobyl
* Serious damage to soil, ecosystem, water, food - expert
* Long-term health monitoring needed for survivors, plant
By Tan Ee Lyn
HONG KONG, April 12 Japan's crippled Fukushima
Daiichi nuclear plant has so far leaked around a tenth of the
amount of radiation released in the Chernobyl disaster, data
showed on Tuesday, leading some experts to warn of serious
long-term health risks.
Japan's Nuclear and Industrial Safety Agency (NISA) and the
Nuclear Safety Commission of Japan estimated cumulative
radiation levels at between 370,000 and 630,000 terabecquerels.
Using a median value of 500,000 terabecquerels, that would
be nearly 10 percent of the total radiation of 5.2 million
terabecquerels released by Chernobyl. The Chernobyl figure was
provided by the Japanese agencies.
"If that is the total radiation so far from the time of
first leakage, that amount is very serious. It's undoubtedly
very bad. That is close to one-tenth of Chernobyl's radiation in
a month," said Lam Ching-wan, a chemical pathologist at the
University of Hong Kong and member of the American Board of
"It means there is damage to soil, ecosystem, water, food
and people. People receive this radiation. You can't escape it
by just shutting the window."
With Japan widening the evacuation zone beyond the initial
20 km (12 mile) exclusion zone and encouraging children,
pregnant women and hospitalised patients to stay out of some
areas 20-30 km from the nuclear complex, Lam said he feared the
radiation leakage may still be far from under control.
"The radiation threat is there and there must be national
radiation surveillance for health purposes ... they must decide
if there should be regular screening for cancer," Lam said.
CALLS FOR LONG-TERM HEALTH MONITORING
Experts are most worried about three radioactive substances
-- iodine-131, caesium-134 and caesium-137 -- all of which can
cause various types of cancer years later.
From studies carried out on survivors of nuclear plant
accidents in the past, as well as the atomic bombings in Japan
during World War Two, the link between exposure to radioactive
iodine and thyroid cancer is most convincing.
Although the radioactivity in iodine-131 fully disintegrates
in 80 days, it can find its way rapidly into people through the
air and through milk and leafy vegetables, lodging quickly in
the thyroid gland, where it can cause DNA damage and raise
cancer risk, particularly in young children.
Among the people who were exposed to the Chernobyl accident
as children, at least 1,800 have gone on to develop thyroid
cancer, a study has found.
Experts called for long-term tracking and monitoring of the
health of survivors living near the plant as well as the
hundreds of nuclear plant workers now battling to get the
Fukushima nuclear plant under control.
These studies will help policy-makers make informed
decisions when setting aside funding and planning healthcare
services in the future, such as cancer screening and therapies.
"You need several metres of concrete to shield yourself from
radiation ... even lead aprons are not going to help," said
Stephen Law, chief of service of clinical oncology at the Queen
Elizabeth Hospital in Hong Kong.
He said whatever protective material the nuclear plant
workers were using would not fully shield them.
"Those workers are the largest group of people now being
exposed to a significant radiation dose and this will improve
our knowledge of managing radiation accidents," Law said.
Lam said regular cancer screening would be important for
people living near the nuclear plant.
"Thyroid cancer is treatable and early detection raises cure
rates. Without monitoring, you will lose the golden window of
opportunity to early treatment," Lam said.
Ben Cowling, a public health associate professor at the
University of Hong Kong said such long term studies would be
very useful for healthcare planning in the future.
"Any information would be useful because there is very
limited information on these kinds of incidents," Cowling said.
"It could happen again in another place at another time."
(Editing by Andrew Marshall)