Fifty years ago this month, a Mainer pushed through one of the most important environmental laws ever passed in the U.S. – an against-the-odds victory to this day responsible for billions of dollars of benefits annually – the Clean Water Act of 1972.

Perhaps nowhere is Edmund S. Muskie’s legislative legacy more valued than in our water-rich, water-bounded state, the once heavily polluted rivers of which drove Sen. Muskie to champion the landmark legislation in the first place.

You don’t need us to tell you how compelling its results have been. Maine’s waterways are cleaner than they were 50 years ago. Portland is one of only 50 water districts in America that does not require a filtration plant. People have returned to rivers and streams up and down the state in ways unimaginable before the Clean Water Act came to be.

Tom Hamilton, right, demonstrates a water quality test in July at Lake Anasagunticook in Canton. Hamilton has been an official water quality monitor for the lake association for 25 years, and measures phosphates, dissolved oxygen, temperature and clarity. A small group of kayakers departed from the boat launch that morning as part of a 50th anniversary celebration of the federal Clean Water Act. Andree Kehn/Sun Journal

As we celebrate its legacy, we find ourselves at another dangerous turning point for water quality. This time it’s not a matter of bodies of water being yellow or brown, malodorous or topped in noxious foam due to a lack of sewage treatment plants. The newer contaminants in our water are far less apparent in daily life.

The biggest threat facing Maine comes from perfluoroalkyl and polyfluoroalkyl substances, the “forever chemicals” known as PFAS – found in a wide variety of water- and grease-resistant packaging, apparel, cosmetics, cleaning products – that have been linked to cancers, weakened immune systems, liver damage, endocrine disruption and more.

These substances are troublingly ubiquitous in our water supply and our soils; they rain down in places that have never otherwise encountered them. They’ve been found to exceed the state limit in drinking water at a host of Maine schools. And, discovery by harrowing discovery, they are devastating Maine farmers’ livelihoods. The crisis in agriculture is due to the use of PFAS-contaminated sludge as fertilizer.

There’s been some movement in the right direction. This past spring, the state passed legislation banning the use of sludge and approved a ban on pesticides containing PFAS by 2030. A legislative panel established a $60 million relief fund – this is likely just the start. That relief has been slow to reach the farms and people who need it.

Last year, Maine became the first state in America to ban almost all products that contain PFAS. Despite broad support for this move, and ever-increasing evidence of the significant risks PFAS pose to public health, there are pockets of resistance. The Maine State Chamber of Commerce and others had the temerity in July to ask state officials to delay the implementation of a separate product reporting law.

In a thoughtful Portland Press Herald op-ed published that month, Dan Marks, wastewater superintendent for the town of Falmouth, drew attention to an aspect of the Clean Water Act that’s no longer fit for purpose because of the prevalence of PFAS, which he described as “the tip of the iceberg.”

“The construction of our wastewater treatment facilities (following the Clean Water Act) was founded on a principle of ‘assimilative capacity,’ meaning we can pollute up to nature’s capacity to absorb that pollution – without detrimental effect. We need to move on from this principle,” Marks wrote.

“These chemicals [PFAS] do not readily break down in nature and even miniscule amounts have an impact on our bodies. Our wastewater is telling us that our environment and our bodies have reached the limits of assimilative capacity.”

The telling isn’t loud enough for some. PFAS are more or less unregulated at the federal level. According to the Center for Biological Diversity, the 117th Congress has already seen at least 19 attacks on provisions of the Clean Water Act alone – one of the few laws under which meaningful regulatory action against PFAS could be taken.

As the federal picture shifts and changes, the responsibility of states to bridge shortcomings becomes enhanced. At the state level, Maine must pursue aggressive regulation, upgrade of water systems infrastructure and major investment in remediation, testing and financial incentives for environmentally sound decision making.

Complementary state bills saved the Androscoggin, the river that set it all in motion for Muskie. Half a century later, the detail and ambition of the response emerging from Augusta will be more important than ever. Let’s use this anniversary as a reminder of what prompt and serious environmental intervention can achieve.