A scientist who regards as plausible the theory that depleted uranium has caused the outbreak of mystery cancers in Iraq said yesterday that the evidence should be tested scientifically. However, Dr Alistair Hay, a chemical pathologist in the medical school at Leeds University, was sceptical about whether the radioactive debris itself could enter the food chain or the water supply and ultimately the human body, causing cancer. 'It could only be incorporated if it was very finely divided up and dissolved and then transmuted into the plant in some way.'
He felt it was more likely that if the depleted uranium was the cause, it was inducing cancer in people who came into very close contact with it. 'You do get radiation-induced cancers, you get leukaemia and cancer of the lymphatic system in particular,' he said. The people most likely to become victims of such cancers are those who come into direct contact with the radiation source.
'The potency of radiation caused by a particular shell decreases the further you are away from it. Its effect is much stronger if you are handling the substance than if you are a few feet or yards away. So those handling these munitions would be in a risk group while those just close to them might not.'
This theory is gaining ground as an explanation for cancers among US and British Gulf War veterans.
An alternative theory is that chemical or biological agents developed by Saddam Hussein's regime were released either accidentally or deliberately at some stage, causing cancers. However, this appears highly unlikely. The chances of such an outbreak of cancers being caused by a single exposure to chemical or biological agents do not appear great, according to Dr Hay.
During the second World War, British and Japanese workers involved in manufacturing mustard gas suffered a high incidence of respiratory tract cancers due to repeated exposure to the substance. However, those subject to one exposure (such as during the Iran-Iraq war) showed no increase in cancers.
The nerve agents in the possession of the Iraqi regime, such as sarin and tabun, have dramatic effects on the nervous system but are not carcinogenic. The same applies to the nerve agent VX which Iraq is suspected of having developed.
According to Dr Hay, the high incidence of double cancers was something that 'somebody needs to have a systematic look' at. The only way to determine the cause of cancers would be through a limited study of the cases looking at common factors, such as the lifestyle, diet and other circumstances of the sufferers, as well as comparing the number of cases now to previous numbers.
During the Gulf War, according to Prof Paul Rogers of the University of Bradford Peace Studies department, the Iraqis deployed missiles with warheads containing aflatoxin, a substance that cause liver cancer months or years after an individual has come into contact with it. There is no evidence, however, that any of these were fired, he says. Iraqi paediatrician Dr Bushra Al-Rebayi says the most striking increase in cancers in Iraq since the Gulf War has been in the number of brain tumours being detected in children. She says the problem is not confined to southern Iraq, but can be seen throughout the country. Dr Al-Rebayi, who lives and works in London and is involved in seeking to provide humanitarian aid for the Iraqi population, says the phenomenon is running in parallel with other unexplained signs of environmental change.
'All over Iraq - even in Baghdad - ordinary trees are dying for no good reason, or are not producing as much fruit as before.' She believes a soil analysis in various parts of Iraq might provide an explanation.
She agrees with Dr Hay that the cancers are unlikely to be have been caused by Iraqi biological weapons. 'They were dropped on the Kurds in the north and used in the Iran-Iraq war without any resulting rise in cancers.'
The situation is made worse by the lack of medical supplies, she says. 'Leukaemias for which there is an 80 per cent recovery rate in the UK are remaining untreated.' Poor nutrition and medical care increase the number of fatalities.
The fact that it can commonly take 15 years and sometimes as long as 40 years between exposure to a carcinogenic agent and diagnosis means that what Lara Marlowe has seen in southern Iraq could be the tip of an iceberg.
Dr Hay warns against jumping to conclusions. He recalled that in Vietnam there had been a widespread belief that dioxins used by the Americans in defoliants during the war were to blame for a high incidence of liver cancer. Ultimately it was established that the high incidence of hepatitis in the country was the actual cause.