The people of the Grassy Narrows First Nation knew something was wrong when the turkey vultures overhead started to fly as if they were drunk. The birds, they would later find out, were suffering the neurological effects of mercury poisoning. So were the area’s eagles, otters and mink. Anything that ate fish from the English-Wabigoon River system, tainted by more than a decade of pollution from a nearby paper plant in Dryden, Ont., seemed to get sick.

Tragically, that included many residents. In the 1970s, members of the community began showing signs of neurotoxicity: numbness, trembling, loss of co-ordination. Certain developmental problems in children linked to mercury poisoning seemed to increase.

The implications of the pollution reached beyond the devastating health effects. The system of waterways is hallowed by the people of Grassy Narrows, and the commercial fishery provided near-full employment. But once the province became aware of the dirty water, it rightly banned commercial fishing. The mercury robbed the residents of their health, their livelihoods and their sacred-held land.

Yet even in the ban’s aftermath, many residents refused to abandon their traditional way of life or were unable to afford food that did not come from the river. Many kept eating the fish. As recently as 2014, a 17-year-old boy from Grassy Narrows died from causes believed to be related to the mercury.

On Thursday, thousands of concerned citizens marched in Toronto to call attention to the crisis — something the community has been working to do for decades. The government, which has been painfully slow to act, should listen.

The story of inaction is a long one. In the 1970s, the province began conducting studies of the problem and its possible solutions. Despite contradictory recommendations, the government decided at the time that allowing the river system to recover naturally would, on balance, be more effective than any remediation efforts.

Three decades later, two reports, including one co-funded by the province, suggest that allowing nature to take its course has not improved the situation much, if at all. Mercury levels seem to have stopped declining in the mid-1980s, and remain well above the level that, according to provincial regulations, should automatically trigger remediation efforts.

So what, if anything, can be done? For decades the government’s response has been consistent: nothing. Remediating the river system, the province has long maintained, is not desirable. In perfunctory public dismissals of multiple reports questioning Ontario’s position, successive governments have claimed that removing the mercury would require a process of dredging that would disrupt and spread the chemical, making the situation worse, not better.

Yet a community-funded report released this week by leading freshwater scientists recommends several solutions other than dredging. The most effective, according to the study, would be adding mercury-free sediment to the river system — a method used successfully in an enclosed portion of it in the early 1980s. About this recommendation the government will only say that more study is necessary.

Perhaps if Ottawa or Queen’s Park had undertaken ongoing, comprehensive environmental and health testing of the community, as residents have long called for, we might already have the answers to these pressing questions. It’s a shameful fact, for instance, that the most robust epidemiological studies of the area were conducted not by the government complicit in the health crisis but by a team of Japanese mercury-poisoning experts.

They concluded that a majority of the community’s residents were affected by Minamata disease, a neurological disorder caused by mercury poisoning. (The province still has not confirmed this diagnosis.) The researchers also corroborated the community’s claim that the compensation package set up in the 1980s — the result of an out-of-court settlement — was so inadequate that it no longer covers most of those in the community made ill from mercury.

The government’s first public response to the new study seemed to reiterate the traditional position that nothing could or should be done. But in the following days the government softened its stance. “[We] do not reject the report,” Gary Wheeler, an environment department spokesman, wrote to the Star. “The ministry agrees…there are a number of important data gaps which prevent a full assessment and recommendations regarding cleanup options.”

That this non-committal shift is the most hopeful development in the sad saga of Grassy Narrows says a great deal. What happens next is what matters. The government should move quickly to do one of two things: work to fix the English-Wabigoon River system and restore the health and livelihood of the community or be fully transparent about why it cannot and find other ways to help and appropriately compensate the victims of their mistakes.

Wynne has apologized for Ontario’s role in the mistreatment of indigenous peoples. She has promised to build a new, respectful relationship and work to undo the wrongs done. Grassy Narrows provides a simple test of sincerity. Let’s see if she means it.