http://www.sundayherald.com/news/newsi.hts?section=News&story_id=13815The
Sunday Herald (Scotland)
21 January 2001
Revealed: how just one
single atom of DU can trigger
cancer
By Rob Edwards Environment
Editor
Publication Date: Jan 21 2001
The furious international
row over the risks of
depleted uranium weapons is set to flare up again
with
the revelation that a single atom of uranium inside
the body is
enough to trigger cancer.
Scientists from a government-funded medical
research
laboratory at Harwell in Oxfordshire have produced the
first
direct proof that a single alpha particle
emitted by uranium can damage
human cells. The damage,
they say, is a crucial step in the development
of
tumours.
Arguments over the health hazards of depleted
uranium
(DU) have been raging since the UN Environment
Programme
announced earlier this month that eight out
of 11 sites in Kosovo were
contam inated with
radioactivity. Nearly one million rounds of
ammunition
containing 300 tonnes of DU have been fired in the
Balkans
and Gulf wars over the last 10 years, mostly
by US forces.
The new
evidence will reinforce the growing chorus of
demands for a ban on the use
of DU in weapons, at
least until the health risks for soldiers
and
civilians have been fully investigated. Last week the
European
Parliament voted 626 to 394 in favour of a
moratorium while an independent
study into the
potential health risks was carried out.
Although Nato and
the British Ministry of Defence
continue to insist that there is no
evidence that any
ill health has been caused by DU
munitions,
politicians, war veterans and scientists maintain
there is a
problem, particularly with excess cancers
and leukaemias. Tomorrow the
World Health Organisation
is sending a team of experts to Kosovo to
examine
whether there are any links between civilians exposed
to DU and
cancers.
The new British study was conducted by the Radiation
and Genome
Stability Unit at Harwell in association
with Mount Vernon Hospital in
London. Groups of human
blood cells were exposed to a single alpha particle
in
the laboratory and left to divide a dozen times
or
more.
Researchers found that 25% of the daughter cells
had
distinctive patterns of broken and bent chromosomes.
This effect,
christened "radiation-induced genomic
instability", is thought to be part
of the complex
chain of biological events that can end up as
cancer.
"This work shows directly for the first time that even
a single
alpha particle can induce genomic instability
in a cell. That may be
important in assessing risks of
cancer from alpha-emitting radionuclides in
the body,"
said the Harwell unit's director, Professor
Dudley
Goodhead.
"It suggests that even the smallest amount
carries
some, very small, risk. However, for materials such
as
low-activity uranium it may well be that the radiation
is less
harmful than chemical effects of the metal in
the cell."
Although alpha
particles are not a very penetrating
form of radiation, when inside the
body they can do
significant harm to any living cells they happen
to
pass through. They are emitted by plutonium and other
radionuclides
as well as uranium.
Last week, the Ministry of Def ence admitted
that
traces of plutonium could also be present in DU
weapons, left over
from processing by the nuclear
power industry. That, experts pointed out,
inevitably
increased the risk because plu tonium emitted more
alpha
particles than DU.
Mike Thorne, a uranium specialist with AEA
Technology,
a spin-off company from the UK Atomic Energy
Authority, also
in Harwell, thought that the new study
strengthened the need to find out
how much DU had
found its way inside people during the conflicts in
the
Gulf and the Balkans.
But he agreed with Goodhead that the chemical
effects
of DU could be even more dangerous than its
radiological impact.
"It is a toxic heavy metal," he
said.
"It would be reasonable to put a
moratorium on its use
as a munition until we have investigated the
amounts
to which people have been exposed."
Most radiobiologists have
dismissed the much
highlighted suggestion that soldiers exposed to DU
in
Kosovo in 1999 could already have developed leukaemia
as a result. It
was much too soon after the exposure
for the disease to be diagnosed, they
said.
But Sue Roff, a radiation res earcher from the Centre
for Medical
Education at the University of Dundee, has
dug up evidence that suggests
the radiation-induced
leukaemias can develop surprisingly quickly. The
first
cases were discovered in Hiroshima and Nagasaki in
1947 and 1948,
just two or three years after the US
destroyed the cities with atomic
bombs.
"In studies of patients who have received radiation
therapy, the
period of greatest risk for developing
leukaemia has been reported as two
to five years after
exposure.
"I am aware of at least six men, most in
their 20s,
who were diagnosed with leukaemia within five years of
their
participation in the UK nuclear weapons tests in
the 1950s and 1960s," Roff
told the Sunday Herald.
"In Japan, leukaemia was the first malignancy
that
appeared among the survivors and this fact triggered a
major
research study which is still in operation
today.
"I would have thought
that the appearance of leukaemia
among soldiers selected for their fitness
for active
duty would trigger similar studies as part of
the
government's duty of care."
