Serbia on toxic sludge alertIn Europe, News Headlines, Pollution, Videos Video Report: Serbia is monitoring the River Danube for signs of pollution after the Hungarian toxic spill reached the major European waterway. Natalie Armstrong reports. Share Tweet Topics: Danube Hungary Toxic Red Sludge Spill 2010 Pollution Serbia on Danube toxic spill alert redsky Leave a reply: Cancel ReplyYour email address will not be published.