The controversial Talus Dome has dents in about a dozen of the stainless steel balls that make up the sculpture perched on the edge of Fox Drive and the Quesnell Bridge.

Rust can also be seen on some of the balls.The marine-grade stainless steel only rusts if it comes in contact with a contaminant like the metal in a hammer.

However, David Turnbull, public art conservator with the Edmonton Arts Council, is reluctant to place the blame on vandals.

"Without video evidence, without someone witnessing anything, all we know is that some are dented, they have corrosion, they need to be replaced," he said.

Turnbull said damage was first noticed on a few of the balls late last year. Now that that the damage is more extensive, it's worth the expense to hire a contractor to repair the sculpture, he said.

The work should be done by the end of September. The damage is estimated at around $5,000.

Turnbull is disappointed by the damage but said it happens.

"It's the nature of artwork that is in the public realm...you can't control things," he said.