How will Balkan nations respond to a lake covered in trash?

Trucks and building machines are parked on a river dam in southwest Serbia, but not for construction work. Instead, huge cranes are being used to clear tons of garbage crammed at the foot of a hydropower plant.

Serbia and other Balkan nations are overwhelmed by communal waste after decades of neglect and lack of efficient waste-management policies in the countries aspiring to join the European Union.

Burning rubbish dumps can be seen from the roads, plastic bags are hanging from trees, and islands of waste are floating down the region’s rivers. The problem usually comes into focus in winter, when swollen waters sweep over landfills, pushing the garbage toward hydropower dams.

This has been the case at Potpeć Lake after a spate of rainy and snowy weather in December and early January. The surface of the lake became covered in a thick layer of waste ranging from plastics to rusty metal scraps and tree trunks.

The garbage has been swept downstream by the Lim River, which feeds the Potpeć dam. The Lim originates in neighboring Montenegro, passing through several municipalities and their waste sites in both Montenegro and Serbia.

“Based on a recent study, we found out that in these towns, in the five municipalities in Montenegro and three in Serbia, about 45,000 tons of waste are collected [per year],” said Predrag Saponjic, the Lim River hydropower plant system manager. Looking at the rubbish-strewn lake, he added that “even if only a fraction of that waste ends up in the Lim River, we get this.”

Environmentalists in the Balkans have warned that because most landfills aren’t managed properly they leak toxic materials into rivers, threatening ecosystems and wildlife.

Bosnia, too, has reported a garbage pileup that endangers the hydroelectric dam on the Drina River, near the eastern town of Visegrad. The Lim is one of the tributaries of the Drina, which makes their waterways – and garbage flows – closely connected.

The two emerald-colored rivers – the Drina flows along the border between Serbia and Bosnia – during summer are favored by adventurers and rafters who enjoy the winding waterways and seemingly pristine nature.

While Balkan nations have been struggling to recover following a series of wars and crises in the 1990s, environmental issues often come last for the countries whose economies are lagging far behind the rest of Europe and where public funds are vulnerable to widespread corruption.

Jugoslav Jovanovic, from Serbia’s state-run Srbijavode company that is in charge of the country’s water system, put the waste problem down to “our neglect and lack of care.” Landfills are located too close to rivers and are overfilled rather than closed down over the years, he warned.

“If we find ourselves forced to do this year after year, then that’s not really a solution,” he said of the clearing operation. “We must find common ground and solve this by joining forces.”

Serbia, Montenegro, and Bosnia have held meetings on the issue, but little has been done. The Balkan countries also face other environmental emergencies, including dangerous levels of air pollution in many cities.

Experts predict the clearing of Potpeć Lake will take few weeks, depending on the weather. However, all the garbage from the water will end up again on a landfill in western Serbia.

Goran Rekovic, an activist from the nearby town of Priboj, said raising public awareness about pollution is a key goal, along with “institutional and systematic” solutions. These are needed also if Serbia and other Balkan countries wish to move closer to EU membership.

“This is not the European Union’s obligation. We should not be doing this for them,” Mr. Rekovic said. “The reason why we should take care of our environment is for our own future generations.”

This story was reported by the Associated Press. Jovana Gec and Marko Drobnjakovic contributed to this report.