HALIFAX -- The federal government has pledged to spend $100 million to help clean up the Boat Harbour effluent lagoons -- long considered one of Nova Scotia's most polluted sites.

The sprawling lagoons, which are near the Pictou Landing First Nation in northern Nova Scotia, are contaminated with millions of litres of treated waste water from the nearby Northern Pulp paper mill.

Sean Fraser, the local Liberal member of Parliament, made the announcement Thursday at the Pictou Landing First Nation.

"Cleaning Boat Harbour has been a top priority of mine from the first day I took office," he said in a statement.

"This project will help reconnect the Pictou Landing First Nation community to their traditional lands in pursuit of reconciliation. This once-in-a-generation investment exemplifies our commitment to protecting Canada's environment."

Before the mill was built in the late 1960s, Boat Harbour was used for recreation and harvesting food. The local Indigenous community also gathered ceremonial and medicinal plants from the saltwater habitat.

The federal money will be used to help restore the lagoons to their natural state as a tidal estuary that empties into the Northumberland Strait -- the body of water that separates Nova Scotia from Prince Edward Island.

The plan calls for removing contaminated soil and sediment, which will help restore fish and bird habitat and protect traditional fishing and hunting lands for the local Mi'kmaq population.

Andrea Paul, chief of the Pictou Landing First Nation, said the project will help the community begin an important healing process that will end decades of trauma caused by "environmental devastation."

"We are closer to our youth one day enjoying ... land that our elders played at, swam, fished and hunted," she said in a statement.

"We cannot wait for this land to be returned to its natural state -- land that we can one day all enjoy."

The mill's parent company, Paper Excellence, has been ordered by provincial legislation to shut down the treatment facility that pumps effluent into the lagoons by 2020.

The company, which employs more than 300 people at the mill, has warned it will be shut down unless it can dump millions of litres of waste water directly into the Northumberland Strait.

In March, the Nova Scotia government told the company it must provide more information about its plan to pump 85 million litres of waste daily into the strait.

The company has said it can't meet the 2020 deadline, but Premier Stephen McNeil has insisted that date won't change.

The Nova Scotia government has already committed more than $100 million toward the overall cost of the cleanup.

"As a province, we remain committed to returning Boat Harbour to its natural state so the people of Pictou Landing First Nation can enjoy and benefit from this land for generations to come," provincial Health and Wellness Minister Randy Delorey said in a statement.