Friday, November 5, 2010

Soil takes decades to recover from toxic spills

Science 2.0: With the BP oil spill in the Gulf of Mexico and the toxic mud spill in Hungary, the big question is how long will recovery take? Unfortunately, yet at least scientifically apt, is that there are previous disasters to help answer those questions.

Twelve years ago there was a spillage of pyritic sludge from a mine at Aznalcóllar, in the Doñana National Park in Spain, where four million cubic meters of acidic water and one million cubic meters of waste material containing high levels of toxic compounds contaminated more than 4,500 hectares of the rivers Agrio and Guadiamar and the land around them. Now, a team led by the National Museum of Natural Science (NMNS-Spanish National Research Council) states that the soil affected has recovered "reasonably well". Their study of nematodes (microscopic soil worms that are indicators of the biological state of soil) confirmed the "enormous" impact of heavy metals and is useful for predicting the effect of the red mud spillage in Hungary.

One month ago, a spillage of red mud with toxic material from the aluminium holding pond in the city of Kolontar occurred west of Budapest in Hungary and reached the Danube. The immediate consequences were the loss of ten human lives and the destruction of houses and crops. In Spain, the Aznalcóllar spillage in 1998 affected the fauna in the soil of Doñana and exterminated several species. Some nematodes disappeared in the first few months after the disaster. …

"Red sludge" alumina plant accident, Devecser, Hungary. Shot by the Hungarian government, Wikimedia Commons

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