快猫短视频

THREE years after a devastating toxic chemical spill, birds in southern
Spain鈥檚 Do帽ana 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. Do帽ana was declared a World Heritage Site in
1994.

On the night of 24 April 1998, the dam of a tailings lagoon of the
Aznalc贸llar 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
Do帽ana 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 Do帽ana Biological Station found that birds living in
the affected area had potentially lethal levels of heavy metals in their blood
(快猫短视频, 24 October 1998, p 24).

Now, cell biologist Felipe Cort茅s of the University of Seville and his
colleagues have found that Do帽ana鈥檚 white storks are suffering continuing
genetic damage. Cort茅s 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 Cort茅s.

Damage to DNA in eggs and sperm could be inherited by future generations, and
cause birth defects. Cort茅s鈥檚 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 鈥渃ould take
years to fade away鈥�, 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 鈥渉ave
led to a significant environmental recuperation of the affected area鈥�.

But environmentalists say that heavy metals will continue to cause long-term
damage to the animals in the park. 鈥淭his is very dangerous for birds in
general,鈥� says Fran Romero of the Spanish Society for Ornithology. Cort茅s
says it is essential that a monitoring system is put in place to assess the DNA
damage in a range of Do帽ana鈥檚 wildlife.