Toxic liquid creeps toward an olive grove

In a race against time, officials built dams around the 75,000 hectare park to try to stop the stream of poisonous spill.

Rare plants and wildlife were at risk of being destroyed by the concoction of zinc, lead and cadmium.

Rescue measures work

The Environment Minister Isabel Tocino, who visited the sight within hours of the spill, said engineers had succeeded in blocking off the river.

"Fortunately Do�ana has been saved," she told national radio.

"The contaminated waters will not reach the wetlands because all the systems that were put in place yesterday worked."

Thousands of hectares of farmland have been poisoned

But the authorities say the waste from a minerals plant has already significant ecological damage, with 10,000 hectares of farmland along the banks of the river poisoned.

The mayors of seven towns along the river have warned citizens not to drink from ground wells.

Farmers were also told to keep livestock away from the river. Fishing was also expected to be affected.

Outcry

At the height of the operation the biggest outcry came from environmental groups like Greenpeace, who are concerned about the welfare of Europe's largest natural reserve where hundreds of species of flora and fauna flourish as nowhere else on the continent.

They described the accident as a crime against nature and want the Spanish attorney general to take legal action against the foreign group that owns the mining company.

Environmental groups say they had warned before about a disaster waiting to happen, but were ignored.

But the mining company said no signs of instability had been detected in the dam before the breach.

Work was under way to reconstruct the dam to avoid further discharges it said.