91av

THREE years after a devastating toxic chemical spill, birds in southern
Spain’s Doñana National Park are showing genetic damage that could last
for generations.

The park, near Seville in Andalusia, is an important stopover for some 6
million migrating birds. Doñana was declared a World Heritage Site in
1994.

On the night of 24 April 1998, the dam of a tailings lagoon of the
Aznalcóllar pyrite mine near Seville burst. According to the World Wide
Fund for Nature, nearly 2 million tonnes of tailings and 5.5 million cubic
metres of acidic water laced with heavy metals flooded into the Agrio and
Guadiamar rivers and down to the Entremuros marshes on the edge of the
Doñana National Park.

Despite a concerted effort to clean up the water in the marshes and remove
poisonous sludge, problems remain. Heavy metals such as arsenic, thallium, zinc,
cadmium and manganese have entered the food chain. Shortly after the disaster,
scientists at the Doñana Biological Station found that birds living in
the affected area had potentially lethal levels of heavy metals in their blood
(91av, 24 October 1998, p 24).

Now, cell biologist Felipe Cortés of the University of Seville and his
colleagues have found that Doñana’s white storks are suffering continuing
genetic damage. Cortés tested blood taken from white stork chicks 14
months after the spill for DNA damage. He found that chicks living close to the
park had levels of genetic damage between 10 and 20 times higher than those
living further away. The damage probably results from heavy metals and toxins in
their food, says Cortés.

Damage to DNA in eggs and sperm could be inherited by future generations, and
cause birth defects. Cortés’s team will shortly publish results showing
that storks sampled last year continue to show significant DNA damage. Kites in
the park have also been badly affected. The effects of the disaster “could take
years to fade away”, he says.

Three years after the accident, the Guadiamar area is slowly recovering.
Researchers from the Andalusian Environment Ministry submitted a paper to a
conference in Madrid this month in which they wrote that clean-up efforts “have
led to a significant environmental recuperation of the affected area”.

But environmentalists say that heavy metals will continue to cause long-term
damage to the animals in the park. “This is very dangerous for birds in
general,” says Fran Romero of the Spanish Society for Ornithology. Cortés
says it is essential that a monitoring system is put in place to assess the DNA
damage in a range of Doñana’s wildlife.