Back in June 1943, Bates College professor Walter Lawrance headed out to the banks of the Androscoggin River, to eight different spots, and took a whiff.

He went back every day, every summer, and did the same thing, for 24 years.

The chemist’s nose kept the official record of just how bad the river smelled. In a science that was probably well-reasoned but lost over time, the river got an average odor rating of 36 that first year. At its worst in 1941, when public indignation – and the stink – reached a pitch, he gave it a 65. (He smelled into the past, apparently, for that estimate.)

By the summer of 1958, according to Lawrance’s nose, the river’s smell hit zero on his scale and stayed there. But while it wasn’t odiferous by his standard, the problem wasn’t over.

The Androscoggin River popped up in Newsweek in 1970, in a cover story on “The Ravaged Environment,” as one of the 10 “filthiest” rivers in the U.S.

That’s a lot of negative history for any river to overcome.

Today it’s unquestionably better – there’s no one assigned to sniff it – but it is still the worst in Maine.

Several miles of river don’t meet the minimum Class C cleanliness standards, most consistently at a dammed, 6-mile length called Gulf Island Pond in Turner, and more sporadically just below Lewiston-Auburn. There, during heavy rains, raw or barely treated sewage pours straight into the water from the cities’ treatment plant.

A 1-mile stretch around Livermore Falls that had also failed to meet standards recently got a tentative nod: Judging by certain bugs and fish, it appears to be up to par.

“It’s definitely progress,” said David Courtemanch, director of the Division of Environmental Assessment at the Maine Department of Environmental Protection.

The laundry list of nagging issues: phosphorous (can lead to algae blooms; when algae sinks, the decay leads to less oxygen); organic waste (it rots, also grabbing up oxygen); suspended solids (smother life at the bottom); dioxin (increases risk of cancer and liver damage, builds up in fish); and PCBs (probable carcinogen, causes rashes, builds up in fish).

The culprit, for the most part: industry and municipal treatment plants.

“Years and years and years ago, we didn’t have fish kills in the river because we didn’t have fish to kill,” Courtemanch said. Most species have rebounded with the exception of salmon and trout, he said, and Inland Fisheries and Wildlife has been restocking the latter.

Bass, sunfish and suckers have come back on their own.

All other large rivers in Maine are at least Class C, essentially healthy enough to swim in or fish. (Courtemanch said some do face similar sewage overflow issues that bring them below class during rain storms.)

The Kennebec, second-biggest in Maine, is all A or B, except for 10 miles below the Sappi paper mill in Skowhegan. That river also had historic low points.

In the 1960s, when more mills dotted its banks, the Kennebec had a 12-mile stretch of water with no dissolved oxygen. Fish and bugs couldn’t breathe, period.

“It was easy to make attainment (on the Kennebec) because (industry) went away. In the Androscoggin, it’s a little different,” said Carl Marsano, senior environmental engineer at the DEP.

Paper mills in Gorham, Rumford and Jay are going strong. Another dozen businesses and municipalities return millions of gallons of treated wastewater to the river every day.

Marsano’s been reading old reports like the ones penned by Lawrance. It’s interesting, he said, to see what wasn’t even counted as pollution back in the day.

In a 1941 study for the state Sanitary Water Board that took stock of all waste going into the river, such materials as wax, dirt, soap and dye deposited by textile mills hardly raised alarm.

“In today’s day and age, we would be very concerned because of the chemicals they use. They weren’t at all concerned with toxins,” Marsano said.

In that same assessment, it’s noted that manure and cattle blood from an Auburn slaughterhouse were kept out of the Androscoggin River, but pig’s blood – 250 gallons a week – washed right downstream.

By the time the river made it into Newsweek, it was listed as among America’s “filthiest” with company like the Ohio River and the Merrimack between New Hampshire and Massachusetts. Just who named it one of the 10 worst – a notorious ranking repeated over and over through the years – is a bit of a mystery. The magazine never cites a source.

It wasn’t American Rivers (they didn’t start a “most endangered” list until the 1980s,) it wasn’t the Environmental Protection Agency (they didn’t exist yet and don’t do an annual list now) and people contacted at Maine’s DEP aren’t sure, either.

“The Androscoggin was, by all the contemporary water quality measures, grossly overloaded and pretty much dead. So I don’t think you can get much worse than that. But I also presume there were probably more than just 10 ‘dead’ rivers nationally at that time,” Courtemanch said.

The latest data on the river’s health this year hasn’t been analyzed yet. What is known: There have been no algae blooms, a positive sign.

The Androscoggin is on track to meet Class C around Gulf Island Pond in 2010, according to Brian Kavanah, director of the Division of Water Quality Management at DEP.

But that’s if the current discharge permits hold for Verso Paper in Jay, NewPage in Rumford, FPL Energy and the Lisbon Falls treatment plant. All four bodies have either appealed their own permits, appealed something in someone else’s, or both, he said. A public hearing date in front of the Board of Environmental Protection hasn’t been set.

It’ll be something the next governor has to keep wrestling with.

By 2014, after millions are spent to separate sewage and groundwater systems, sewer overflow around L-A is supposed to be limited to one spill a year, Kavanah said. That’s what the cities have agreed upon with DEP. “It would be a vast improvement over what’s happened in the past,” he said.

Getting to zero overflow will be a political and monetary challenge – also something the future governor will have to deal with.

As for Lawrance, he logged over 17,000 miles smelling the river. Some stamina. He earned the nickname “The River Master” and in a 1978 interview with the Sun Journal refuted that fumes coming off the river were once so bad it peeled paint off houses.

It was only so bad “jewelers couldn’t keep their silver clean. It would turn brown.”