LESSONS LEARNED FROM THE CYANIDE AND HEAVY METAL ACCIDENTAL WATER POLLUTION IN THE TISA RIVER BASIN IN THE YEAR 2000

摘要

On 30 January 2000, a tailings pond burst at a facility near the city of Baia Mare, Romania which was reprocessing old mining tailings and re-depositing the waste sludge into a new tailings pond. This led to approximately 100,000 m~3 of waste water containing up to 120 tons of cyanide and heavy metals being released into the Lapus River, then traveling downstream into the Somes and Tisa rivers into Hungary before entering the Danube. The cyanide caused acute toxicity for different aquatic organisms (fish, phytoplankton, zooplankton, macrozoobenthos). On 10 March 2000, another tailings dam burst in Baia Borsa in the same region close to the Ukrainian border. While some of this material was retained within the dam complex, 20 thousand ton of sediments containing high concentration of lead, copper and zinc were then released into the Novat River, a tributary of the Viseu and Tisa rivers. The heavy metals were transported mainly in the suspended sediments along the Tisa River. In different sedimentation zones the settled polluted sediment increased the lead, copper and zinc concentration of the bottom sediment up to 1000 mg/kg order of magnitude. The above noted accidents revealed the lack of information on the potential pollution sources in the Tisa river basin. A relevant inventory of the potential pollution sources was compiled for the Tisa river basin after the above noted accidents.