More than a month after a disastrous cyanide spill at a gold mine in Romania killed hundreds of tons of fish in the Tisza and Danube rivers and polluted the drinking water of millions of Eastern Europeans, the affected ecosystems are only now beginning to show signs of recovery. In Hungary, which was most hard-hit by the pollution, officials yesterday lifted a water quality alert on the Tisza after no dead fish were found in the water during a 24-hour period. The spill, which some experts have called the worst environmental disaster since the 1986 Chernobyl nuclear accident, has brought a new urgency to environmental protection in the region, which had fallen from the agenda of many Eastern European countries as they focused on bolstering their economies. A special European Union task force is studying the spill’s cause and effects and drafting a list of potential industrial hot spots all over Europe where environmental problems could surface.