Spill affecting Donana National Park

On the 25th April 1998, a spill equivalent to 500 Exxon-Valdez tankers leaked from a waste settlement lagoon at the Apirsa mine near Saville. Spilling into the Guadiamar River, it eventually reached one of Europe's premier wildlife sites - the Donana National Park in southern Spain. Upto 6.7 million cubic yards of highly toxic sludge spilled from the lagoon. Comprising extremely high levels of lead, mercury and cadmium, almost all wildlife coming into contact with the spill died. The waters were so acidic people, who tried to rescue animals and pets, needed hospital treatment for burns.

The impact of the spill cannot be underestimated as Miguel Ferer, director of Donana's Biological Station, said, 'The Donana Park of the next 30 years will be radically different from that of four days ago'
This view was further reinforced by John Prescott, British Deputy Prime Minister, during a visit on 5th June 1998, World Environment Day, when he said, 'We must not underestimate the significance of the Donana disaster. This area is not just important in Spanish national terms it is a major European site and we need to view it as such.'
The Secretary General of World Wide Fund for Nature, Juan Carlos del Olmo was quoted as saying, ' The consequences of this environmental disaster are immeasurable.'

The sand dunes and marshes of the Guadalquivir estuary which make up the Donana National Park are the home to: 361 species of birds (119 species regularly nest there), 29 species of mammals, 19 species of reptiles and 12 species of amphibians. Significantly important species found here include the Mediterranean lynx and the Spanish Imperial Eagle. It is one of Europe's largest protected areas and designated as a Natura 2000 site and a RAMSAR World Heritage Site. Over 6 million migratory birds are estimated to visit this site each year, as it is one of the most important stop overs on the Arctic-Africa migration route. The importance of this site for a number of species is demonstrated by the interest shown in it by the World Wide Fund for Nature. Active in campaigning to prevent development of the site since 1959, the WWF have initiated a legal inquiry into the spill and previous spills from the mine.

So what went wrong. How did one of Europe's most important wildlife sites suffer almost irreparable damage?

The initial claim by Boliden Ltd, the mine owners, that it was an accident and an act of God is increasingly being questioned. As far back as June 1996 a report by Geocisa warns of a weakening of the dam due to slippage of the foundations. Swedish consultants, Golder Associates, also warned of seepage from the tailings lagoon. As evidence mounted, Boliden Ltd finally admitted on the 26th February 1999 that the dam was badly designed, although it blames its contractors and advisers for the incorrect interpretation of the geological data. The underlying geology of the site consists of marls; clay containing micrite, a carbonate mineral. The current belief is that the foundation failure occurred because of attack from acidic water and the swelling of clay minerals. Rafael Baena Escudero of the Department of Physical Geography and Regional Geographic Analysis summed up the consequences: 'In this case, a complete lack of foresight emerged. The dam was built on top of expansive clays. Within these clays, deformations have occurred, which were propagated to the soil, readjusting the blocks whenever a movement occurred. In this sense, the seepage through the marls has the effect that these layers, the phylosilicates, swell and expand their volume. The opposite happens when they dry out and force the shrinking of the clay. This movement of expansion/contraction is constant and should have been accounted for. Especially, after the inclinometers had become deformed: something was moving. - This is a matter of general negligence and not a problem of nature.'

Other activities in the area by the mining company are also thought to have played a role in the breach of the dam. Locally, blasting was being undertaken and it is also thought that the lagoons were operating at a higher level than they were designed for, so adding extra strain onto the foundations. The threats to the park are not yet over though. Boliden Ltd on 7th April 1999 warned that due to further displacements of upto 14 centimetres, there is a real risk of another breach. The inquiry judge had previously refused Boliden to undertake stabilisation work in case it hindered the investigation. Despite this risk of another breach the company recommenced mining activity on 6th April 1999.

Long-term consequences of this spill are not known. Many of the metals found in the spillage where highly toxic: cadmium, lead and mercury for instance. Zinc was also released in high quantities; estimated loss of 120,000 tones that compares with the mine annual output of zinc of 125,000 tons. Financially the cost of clean up of this spill has been put between $100 and $200 million. A cost so great that the Spanish government is making a claim against the parent companies of Boliden, Canadian Boliden Ltd. and Swedish Trelleborg AB, in case the Spanish company is placed into receivership. But from a wildlife point of view, we can only sit and wait to see the impacts. It is thought that the clean up operation could take upto a decade and still leave highly contaminated soil. Even with most of the metals cleaned away, the pollutants involved can bioaccumulate and magnify along the food chain over a number of years. Indeed the first evidence of impact on migratory birds seems to be showing itself. Greylag geese, overwintering last year at Donana, may be suffering cadmium and lead poisoning with upto 10 per cent in imminent danger of dying.

Seepage from the mine is still entering the Guadiamar River at a rate of 86,400 liters of acidic water per day according to the Environmental Ministry of Andalusia. Much is coming from the contaminated subsoil as a result of the tailing dam. And this is one of the biggest problems in cleaning up after the spill. Such a vast amount of contamination was caused both of the soil and possibly the groundwater, trying to recover all the waste is impossible and movement of the pollutants will continue within the area for many decades and indeed movement will happen every time it rains or the wind blows.