Unsurprisingly, nearly four weeks of bombing are wreaking havoc not only on Serbia's military machine, but on its land, air and water as well.

Immediate concern centres on the fate of the Pancevo complex in Belgrade's northern suburbs.

Pancevo is a combined petrochemicals and fertiliser factory and oil refinery. It was hit on 18 April, and the Times newspaper reported "a toxic cloud of smoke and gas hundreds of feet" in height.

The Danube runs to the Black Sea

The report said the cloud contained the toxic gas phosgene, chlorine, and hydrochloric acid. That afternoon the Serbian Environment Minister said the amount of carcinogenic matter in the air over Pancevo was 7,200 times above the permitted level.

The Times said workers at the complex decided to release tons of carcinogenic ethylene dichloride into the Danube to avoid the risk of an explosion.

Pancevo lies on the river, and the pollution is expected to go downstream to Romania, Bulgaria and into the Black Sea.

Aquifers threatened

But it is not only riverborne pollution that is causing concern. Dr Momir Komatina, a hydrogeologist, says the region's underground water sources are at risk.

Gasmasks at the ready as Pancevo burns

Groundwater is estimated to supply 90% of Serbia's domestic and industrial needs. Dr Komatina says pollution from the effects of the bombing is a problem "not just for our country but for southern Europe".

The Macedonian Environment Ministry is worried about airborne pollution. It says furans and dioxins - toxic and carcinogenic substances - are being released as the bombs explode, and carried for long distances by the wind.

And there is persistent concern over depleted uranium (DU) munitions. DU is a very dense metal, which helps it to penetrate armour effectively.

It is also toxic, carcinogenic, and radioactive. It is blamed by the Iraqis, and by some veterans, for a range of health problems in southern Iraq, where it was used in 1991.

A recent conversation was instructive.

BBC News Online:"Is NATO using DU?"

Nato spokesman:"Nato is not using nuclear weapons."

BBC News Online:"Thank you. But that is not what I asked."

Nato Spokesman:(laughs).