Moscow is concerned about the possible consequences should the toxic material cross the border. But the Chinese side has said the authorities are taking all necessary measures, with several teams engaged in collecting barrels along the Songhuajiang river, Russia’s Emergency Ministry said. China has constructed eight barriers to prevent the barrels from reaching Russia’s Amur River.

“So far no changes in the water quality have been detected,” Ekaterina Potvorova, spokeswoman for the Far East regional center of the Emergencies Ministry told RT. “At the same time, Russian specialists have registered no changes in the water quality for the past several days in the two nearest regions.”

There is additional round-the-clock water-quality monitoring of the Amur River and, at present, there is no health risk for the people living in the area, Potvorova added.

However, not everybody is so optimistic.

Evgeny Shvarts, from the Russian branch of the World Wide Fund for Nature, says if any of the barrels spring a leak, the environmental impact will be massive.

“We still don’t know how much of the hazardous material remains in the river. Even if only a few of the full barrels leak toxic chemicals get into water, no matter where this happens, the effect on the rivers’ biological resources will be huge and extremely negative,” Shvarts said.

Since the Amur River is the major source of fresh water in Russia’s Far East, many locals are extremely concerned about the situation.

“They say they are trying to intercept [the barrels], but I still think some will eventually end up here. Some say they're leaking and the chemicals will come anyway,” says one local resident.

China has been responsible for contaminating Russian water on previous occasions. In November 2005, over 100 tons of benzol and its derivates were washed into the Amur River as a result of a major accident at a Chinese chemical plant. The total area of contamination reached 200 kilometers.

“It's not the first time we've had problems like this. In the winter there was a big chemical spill and we had to use water filters. China has to find a way to prevent these things, or we won't be able to drink this water at all,” says a local.