快猫短视频

RADIATION from one atom of depleted uranium lodged in your body could give
you cancer, British scientists have found. This is the first direct evidence
that a single alpha particle could do this, suggesting that no dose is too low
to trigger a tumour.

The risk is small, and any cancers caused will take years to develop. But
experts say the revelation reinforces the need to check the levels of uranium in
soldiers and civilians affected by wars in the Gulf and the Balkans
(see 鈥淎fter the war is over鈥�).
More than 900,000 rounds of ammunition containing a total of some 300
tonnes of depleted uranium (DU) were fired in those conflicts over the past 10
years, the vast majority by US forces in the Gulf.

Arguments about the health dangers of DU contamination have been raging this
month following an announcement by the UN Environment Programme that it had
found radioactivity from DU munitions at 8 out of 11 sites in Kosovo. But
radiobiologists reject the widely publicised suggestion that DU could have
already caused leukaemia among veterans of the 1999 Kosovo campaign. Radiation
takes more than two years to induce the disease.

The long-term risks from DU dust lodged in the lungs are different, however.
A team from the Medical Research Council鈥檚 Radiation and Genome Stability Unit
in Harwell in Oxfordshire and Mount Vernon Hospital in London has just revealed
how a single alpha particle can damage human white blood cells.

After the irradiated cells were allowed to divide a dozen times, the
researchers found that a quarter of them contained patterns of broken or
distorted chromosomes. They believe this phenomenon, known as 鈥済enomic
instability鈥�, is a key part of the complex chain of biological events which over
years can lead to cancers
(快猫短视频, 11 October 1997, p 36).

Dudley Goodhead, director of the Harwell unit, thinks this may have important
implications for assessing the dangers of cancer from alpha-emitting
radionuclides inside the body. 鈥淚t suggests that even the tiniest amount carries
some, albeit very small, risk,鈥� he says.

鈥淭his means it is important to undertake studies into the deposition and
retention of DU in the body so that they can be compared with levels of
naturally occurring uranium,鈥� adds Mike Thorne, a uranium expert from AEA
Technology, also at Harwell.

Radiation is not the only danger with uranium. Goodhead and Thorne both note
that the chemical toxicity of DU could be more harmful. 鈥淚t 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,鈥� says Thorne.

And despite British government assurances that inhaling dust from DU weapons
does not increase the risks of developing cancers, Britain鈥檚 National
Radiological Protection Board confirmed to 快猫短视频 that breathing
in uranium dust does result in an increased risk of lung cancer. 鈥淭he doses to
lymph nodes are much lower than those to the lung so the risk is much less,鈥�
says the NRPB鈥檚 Michael Clark. 鈥淲e are not aware of any risk of brain cancer
from inhalation of DU dust, but there can be a risk if DU is taken into the body
via an open wound rather than inhaled.鈥�