The city of Bangor and the Maine Air National Guard are wrapping up $600,000 worth of projects to capture runoff from their de-icing operations, but only time will tell whether the new systems reduce pollution in nearby Birch Stream.

Airplane de-icing began early this month, and residents of Griffin Park, a city-run apartment complex, say that the odd, “yeasty” smell and pounding headaches, which they believe are related to the chemicals running in Birch Stream, are back.

Since the airport was built more than 50 years ago, rainwater that runs off the facility’s miles of pavement has been piped into Birch Stream, a small tributary of Kenduskeag Stream that in turn runs into the Penobscot River.

In April, local residents began complaining and discovered that the chemicals used to remove ice from planes – primarily an antifreeze called propylene glycol – was running straight into their back yards.

The problems continue to this day, said Ann Birmingham, who has served as a spokeswoman for Griffin Park residents.

However, Tony Caruso, assistant airport director, said late last week that BIA’s new system to direct de-icing runoff into the municipal sewer system has been up and running since de-icing started in early October.

This summer, the city and BIA installed a new $300,000 system that included a designated de-icing area and a network of pipes and valves to capture de-icer runoff and direct it to the city’s wastewater treatment plant. About 90 percent of the project was funded by a federal grant.

At the Maine Air National Guard Base, a separate $300,000 project to construct a holding pond and install a valve that can direct contaminated runoff to the municipal sewage treatment plant should be completed by Thanksgiving, Lt. Colonel Eric Johns of the 101st Air Refueling Wing said Monday.

The work has been spurred by the Griffin Park complaints but would have been required anyway because the Guard base has drastically increased its de-icer use since Sept. 11, 2001, and reached amounts at which federal regulations require a containment plan, he said.

Since frost started appearing on planes earlier this month, the Air Guard has shifted its mission schedule, avoiding the need to de-ice planes by taking off later in the day, after ice has had time to melt. The few dozen gallons of de-icer that have been used were “vacuumed up” and transported to the water treatment system in a tank truck, Johns said.

Bradley Moore, superintendent at the city’s treatment plant, said Monday that the facility has plenty of capacity to handle the de-icer runoff. And no special processes are needed to treat the propylene glycol, which will be very diluted by the time it reaches the plant, he said.

With the new systems in place, there should no longer be any way for de-icer to run into Birch Stream, said Johns, Caruso and assistant city engineer John Murphy.

“Since the end of the last de-icing season, we’ve captured it all,” Murphy said. “I don’t anticipate any problems in the future.”

Yet residents of Griffin Park say that their symptoms have not abated. In fact, they have gotten worse this fall, Birmingham said.

“They’re not fixing the problem. They’re just putting a Band-Aid on it and trying to make themselves look good,” she said of the city and the Guard.

“There’s something going on there,” Birmingham said.

The residents have formed a group that they are calling G.P. CATS – Citizens Against Toxic Stream – and have been working with Maggie Drummond of the Portland-based Toxics Action Center to address the headaches, nausea and asthma that they say plague Griffin Park residents.

Propylene glycol cannot be definitively linked to the health problems being seen at Griffin Park, the DEP said. But Drummond worries that other chemicals could be following the same path into the stream.

“Diverting the de-icer is a great first step, but we need to go further and evaluate what other chemicals are getting into the stream,” she said.

Murphy agrees that something other than propylene glycol could be causing the “perceived problems” in Birch Stream. He said he has visited the streambed several times this fall, photographing old tires, paint cans and even a discarded couch in the stream.

“That’s people pollution. People are slobs,” Murphy said while narrating a slideshow of photographs. “If people are dumping furniture and shopping carts in there, you don’t know what people have dumped in there after dark.”

The DEP sampled water and sediment from Birch Stream on June 4, nearly two months after residents complained about pollution. A final report that was released earlier this month and appears on the DEP Web site supports the idea that airplane de-icing shouldn’t shoulder all the blame.

Overall, the report paints a picture of an unhealthy ecosystem. Bacteria are feeding on the propylene glycol, growing to unnatural numbers, then using up all the stream’s oxygen as they decompose. The sediment shows signs of oxygen deprivation, and previous DEP surveys have indicated that the stream does not support the number or diversity of insects that would be expected.

The June 2003 samples also turned up small amounts of heavy metals, chemicals that are commonly found in solvents or paints and a chemical used primarily in dye production. Though nothing reached dangerous levels, a number of these chemicals are “unexplained” – perhaps the legacy of Dow Air Force Base, which preceded BIA, the report said.

The DEP, Guard and BIA will cooperate to continue testing for the next several years, looking at the stream three times each year in April, July and October.

“We’re actually doing more than the law requires,” Johns said.

But Birmingham and Drummond question why the initial test was delayed until June and then several more tests were scheduled for months when planes aren’t de-iced. They hope to convince the state to study not only water quality in Birch Stream but the air that Griffin Park residents are breathing, and the patterns of health problems that have emerged at the apartment complex.

“People are continuing to get sick,” Drummond said. “There’s plenty more that the state and city could do.”