Senior IOC members have urged the Olympic body and Russian authorities to investigate the dumping of construction waste that has raised concerns of possible contamination of the water supply in the Winter Games host city of Sochi.

The Associated Press revealed that Russia’s state-owned rail monopoly is dumping tons of waste into an illegal landfill in Akhshtyr, just north of Sochi, in violation of organisers’ “Zero Waste” pledge for the Olympics. On a visit last week to the site, AP reporters saw trucks dump concrete slabs into a gigantic Russian Railways-operated pit filled with spray cans, tyres and foam sheets.

“If this is true, I am astonished,” Gerhard Heiberg, a senior Norwegian IOC member and marketing commission chairman, told the AP on Thursday.

“This would be a breach of confidence between the Russian authorities and the IOC.”

“I really hope we will be able to solve this and work together with the Russian authorities to hopefully do something about it, so they can keep their promise of zero-waste program,” Heiberg, who organised the 1994 Winter Games in Lillehammer, said in a telephone interview.

“Somebody from the IOC should go and see this for him or herself and evaluate the situation.”

Canadian IOC member Dick Pound called for urgent action to determine the safety of the water supply.

“If you’re the IOC, you say, ‘Look, we’ve got this report. We’re not in a position from Lausanne to assess it, but if it’s true, this really does compromise your own citizenry and it compromises the games. Could you please give us a quick and reliable report on what the hell is going on?”

As a centrepiece of its Olympic bid, Russia promised the cleanest games ever, saying it would refrain from dumping construction waste and rely on reusable materials.

In a letter obtained by the AP, the Environmental Protection Agency in the area where Sochi is located told the Black Sea resort’s environment council in late August that it had inspected the Akhshtyr landfill and found “unauthorised dumping of construction waste as well as soil from excavation works.”

The report on the dumping came during a week in which Sochi marked the 100-day countdown to the February 7-23 games.

It also comes as the International Olympic Committee and Russian organisers hold the World Conference on Sport and the Environment in Sochi, a meeting intended to highlight positive steps in making the games more ecologically friendly.