Campaigners tour along the river Tisza to collect samples and information on the level of pollution.
The area is at high risk of cyanide and heavy metal contamination.
On January 30th 2000, the dam containing toxic waste material from the Baia Mare Aurul gold mine in North Western Romania burst and released 100,000 cubic meters of waste water, heavily contaminated with cyanide, into the Lapus and Somes tributaries of the river Tisza, one of the biggest in Hungary.
Cyanide is highly toxic, and is lethal to humans and other species even in very small doses.