They waded knee-deep in the muck -- a shoreline obscured by garbage of all sorts and coated with the same black sheen that floated on the waters of the Patapsco River's Middle Branch.
When the five-hour cleanup ended yesterday, more than 100 volunteers had bagged some 5 tons of trash -- hunks of wood and debris, tires, bottles and foam cups, paint cans and waterlogged jugs, and dozens of crack vials and about 1,000 hypodermic syringes.
While volunteers toiled at the on land with rakes, plastic bags and poles equipped with metal spikes to stab trash, others took to the water in seven dinghies, using hooks at the end of ropes to harvest almost 250 tires.
Yesterday's effort -- sponsored by Save Our Streams along with numerous state and city agencies and private businesses -- marked the first cleanup at the site, between the bridges that carry Interstate 395 and light rail trains into the city.
Bill Franswick, a 63-year-old engineer from Lutherville, waded through the marsh-like vegetation about 20 feet from the rail tracks, picked up a syringe and gestured toward yet another light rail train passing overhead.
"It's a sad impression of Baltimore," he said. "I hate to see people think of Baltimore as a garbage dump. We got to find a better way than this."
State and city officials share his concern for the city's image, especially among out-of-towners who get their first glimpse of Baltimore from a northbound light rail train.
Beyond aesthetics, though, the heaps of garbage and refuse pose serious environmental threats, creating a breeding ground for rats and disease, contaminating the water and devastating aquatic life.
All of the waste traveled from elsewhere -- downstream from major storm drains as far as 25 miles away -- to Middle Branch, a habitat for striped bass, blue herring, mallards, perch, egrets and pheasants.
"It's all coming from the neighborhoods, and that's where it needs to be stopped," said Barbara Taylor, executive director of Save Our Streams.
Noting that 100,000 miles of streams flow into Chesapeake Bay, she said: "We talk about restoring the bay but many of the fish come upstream here to spawn. If we don't clean these waters, then one day these fish won't be in the bay.
"It's disturbing to see this much trash, but it's heartening to see this many people out on a sunny Saturday morning. This is dirty, dirty, dangerous stuff."
Just the sight of it is enough to make anybody think twice before littering, said Jeff Dawson, a 22-year-old volunteer from Parkville.
"I think instead of fines for littering, they ought to give people community service and send them out on a cleanup like this," he said. "It'd be a long time before they threw a cigarette butt or trash again."
The trash is to be burned at a nearby incinerator, Baltimore RESCO, which donated its services. The tires, hauled by a barge, are to be recycled.
About five miles from the Middle Branch site, about 40 volunteers turned out for another cleanup yesterday at Canton Waterfront Park.
There, against a backdrop of sailboats, yachts and ships on the Baltimore Harbor's north shore, the volunteers gathered some 80 bags of trash along a shoreline of white rocks.
The Baltimore Harbor Endowment, a nonprofit group that coordinates improvements along the city's waterfront, and a handful of local businesses sponsored the cleanup.
The shore borders a brick promenade that eventually will extend 7.5 miles, from the Canton park to the Baltimore Museum of Industry on Key Highway, connecting Fells Point, Little Italy and the Inner Harbor.
Louise Grabowski, 64, and her friend, Doris Mrowca, 71, came from Highlandtown to spend the morning reaching and raking to pick up what others left behind.
"If I never see another foam cup, I'll be happy," said Mrs. Grabowski.
"We come back, and we know it'll be the same, more trash here, but we tried. At least we tried."