Protesters marched to Queen’s Park Thursday carrying a canoe filled with petitions and letters demanding the province clean up the waterways near the remote Grassy Narrows First Nation in northern Ontario.

More than 35,000 people signed the papers calling on the government to clean up the mercury that has poisoned the local rivers, lakes and fish — and made people sick — for decades.

Three days before the protest, a Star investigation revealed that province had ignored the environment minister’s recommendation in 1984 to cover mercury sediments in the river system.

“People in Grassy knew the river could be cleaned up. Now everybody knows,” said Mark Calzavara, a regional organizer with the Council of Canadians. “There is absolutely no excuse now not to go forward.”

Premier Kathleen Wynne said last week she is “deadly serious” about cleaning up the river system near Grassy Narrows. The provincial government has begun testing the groundwater.

The letters and petitions carried by the protesters call attention to the importance of the English-Wabigoon River system to surrounding communities. Grass Narrows and nearby White Dog First Nations depended on the river for their food and livelihoods until a now-closed pulp and paper mill dumped tonnes of mercury into the water between 1962 and 1970.

Chrissy Swain, who lives in Grassy Narrows, thanked the protesters for their support on Thursday.

“We want our river cleaned,” she said, through a phone pressed to a loudspeaker. “Water is sacred, water is life.”