WINNIPEG — Leaders of a northern Ontario First Nation are demanding action after new allegations about mercury dumping upstream from their community.

Grassy Narrows, near the Manitoba boundary, has dealt with mercury poisoning since the Dryden Chemical Co. dumped 9,000 kilograms of it into the Wabigoon and English River systems during the 1960s.

Earlier this week, media reports emerged about a former labourer at the mill who says that as part of his job in 1972, he buried more than 50 barrels of mercury and salt in a pit near Grassy Narrows.

At a news conference in Winnipeg on Tuesday, Chief Simon Fobister Sr. suggested the new allegations don’t stem from the same site as the acknowledged dumping.

He said that means the First Nation doesn’t know “if those barrels are leaking into the water table and again contaminating the waterway.”

Ontario Premier Kathleen Wynne said her government wants to get to the bottom of the allegations.

She said there’s “engagement right now to try to discern exactly what this alleged source (of mercury) is.”

Ontario’s environment minister and the minister of indigenous relations and reconciliation are scheduled to visit Grassy Narrows on June 27 and are taking scientists with them to try to figure out what’s happening there.

“If there is still a source of mercury we’re going to remove that in the best way possible, and do it was quickly as we can,” said Wynne. “If we can find a way to remove mercury from the sediment in the bottom of the lakes or the river, without disturbing the mercury and making the situation worse — which is what scientists told us previously — then we will move on that.”

The premier said it is critical to “undo that damage if we can” but said she won’t authorize an action that could make the situation worse.

However, members of the Grassy Narrows band have suggested the government has known about the situation for too long without doing anything about it.

“I feel it’s a betrayal of my people,” Judy Da Silva, who has suffered from mercury poisoning, told Tuesday’s news conference.

Meanwhile, the Public of Service Alliance of Canada announced it is partnering with the Grassy Narrows First Nation to launch a campaign demanding safe drinking water in all aboriginal communities.

PSAC president Robyn Benson said access to clean and safe water is a basic human right and added it’s “appalling” that in 2016, so many First Nations communities are forced to boil their water or drink from a bottle.

They have produced a video for their “Thirsty for Justice” campaign focusing on the situation at Grassy Narrows.