The largest Hispanic neighborhood in Alexandria has received word that it is about to die.

Arlandria, or "Little Salvador" as some call the area just south of Arlington, will no longer be a haven for poor Hispanics and other immigrants, but instead a mecca for young professionals.

Developers John Freeman and Conrad Cafritz, who signed a contract effective last Monday to purchase the Layton Estate consisting of 1,057 apartments -- 74 percent of Arlandria's rental housing stock -- are expected to level Virginia's last large housing cluster near the District for low-income people.

The news of the sale, estimated at $30 million, created confusion among the thousands of tenants, nervous concern among city officials, and welcome relief among nearby residents.

"The people are really upset," said Louise Arnold, president of the Alexandria United Tenant Organization and a resident of the Dominion Gardens, one of the apartment complexes affected by the sale.

To calm residents, Arnold called a meeting yesterday afternoon and urged tenants not to take out their frustrations by "not paying the rent or breaking windows."

In the hot sun, as scores of children played on the lawn, 200 tenants joined hands on Milan Drive to sing "We Shall Not Be Moved." Arnold and other organizers told the group there was still hope that they could buy some of their homes or work out a compromise with the new owners. The sale contract is not expected to be made final until September.

"People have lived here 25, 27, 30 years," Arnold said in an interview. "One woman in her eighties told me she thought she would die here, but now she says she'll die because of what's going on."

The apartments of the Layton Estate are home to thousands of Hispanics and Southeast Asians, as well as to some black and some white low-income people, who work at the lowest-paying jobs in the area. Because of the sale, many will have to seek housing farther away from the District and their jobs, straining businesses already short on clerical, cleaning and restaurant help.

Alexandria Mayor James P. Moran Jr., who called the impending changes the "largest displacement in the city's history," said the city has long prided itself on a richly diverse population. Now, he says, it is "facing the realities of living in the most affluent region in the country."

He expects that many of the displaced residents will go south along Rte. 1 in Fairfax or to Woodbridge. There, he says, "they will have no jobs, no day care, no transportation."

Norma Zaragoza has lived at the Dominion Gardens, the largest complex in the Layton Estate, for six years. After leaving El Salvador in 1980, she lived briefly in the District and then moved to Arlandria, where she, her husband and two children pay $425 a month for a one-bedroom apartment. Water and years have warped the wood and enamel in the bathroom, and black patches on the ceiling show where industrial-strength bug spray was used to kill ever-present cockroaches.

"In my mother's house, the mice are in here," she said, pointing to the sagging couch in her living room. Zaragoza's mother lives in the 416-unit Dominion Gardens.

"If I have to leave, I don't know where I would go," she said in broken English. "My husband works in construction in Arlington. I do not have car." She is expecting her third child in September.

Minutes from the Pentagon and the Capitol, the Capital Beltway and National Airport, Arlandria is one of the last close-in sections of Virginia to be redeveloped. For decades, untamed waters from Four Mile Run often flooded Arlandria's lowlands, scaring off the developers from Crystal City a mile north and from Old Town Alexandria a mile south. But in 1980 a $58 million federal flood control project was completed, causing the land values to jump, in some cases more than 100 percent.

Because many of the units have broken windows, peeling plaster and aging plumbing systems, city officials say it could cost $50 million to $80 million to renovate the Layton Estate. Once rebuilt, town houses could fetch the $125,000 they do in adjacent neighborhoods, according to real estate agents. And monthly rents for one-bedroom apartments, now about $400, could soar to $700.

Knowing how attractive and valuable his property had become, Stanley Layton, trustee for the estate of his brother V. Brooke Layton, has been seeking for more than a year a buyer who could afford to pay top dollar and renovate the Dominion Gardens, the 15-story Warner Towers, the five-story Brookside, and the Bruce Street, Alabama, Green and Dixie apartment buildings.

Because Freeman -- who also redeveloped the Abingdon Apartments where 100 percent of the tenants had to vacate last year when some rents were raised $300 -- and Cafritz are not asking for tax-exempt bonds, which are in dwindling supply, the city has almost no say in the pending sale.

Barbara McSweeney, assistant director for Alexandria's Office of Economic Development, said much of her office's service is done in Arlandria. Because many residents do not speak English, she says, it will be particularly difficult for them to find alternative housing. "The majority of new immigrants are going to southern Virginia and Richmond," she said, adding that displaced Arlandria tenants may have to join them.

They like their community now, she said. Many knew each other in the same towns in Guatemala and El Salvador.

"You see people carrying groceries on their heads . . . . You feel like you're in a village in El Salvador," said Barbara Dill, real estate broker with McEnearney Associates. In her new West Glebe Road office, Dill sits just opposite the Layton Estate. She has seen restaurants and businesses sprout up along Mount Vernon Avenue and knew it would be only a matter of time before Arlandria would no longer be a refuge for people who could not afford to live elsewhere.

While the average annual family income of Layton Estate tenants is between $13,000 and $16,000, according to tenant organizer Arnold, the median income in Alexandria was $33,800 in 1985 and $36,000 in the Washington area, according to Washington Metropolitan Council of Government figures.

In the middle- and upper-middle-class areas just south of Arlandria, such as Warwick Village and North Ridge, residents say they are sorry to see so many poor people go but pleased an eyesore may soon disappear. Garbage, beer bottles and discarded drug paraphernalia often are strewn about the streets just minutes from their $175,000 homes.

"It's always been a ragtag area but it's really bad now," said Mary Ellen Meehan, president of the Warwick Village Civic Association. The renovation "will have a ripple effect. It will help all the neighbors and increase property values."

Stephen M. Colangelo, president of the North Ridge Citizens Association, say the upgrading of the area may mean a new thriving shopping area along Mount Vernon Avenue in Arlandria, because now few of the families in his neighborhood shop there. "We're wrestling with this. It disturbs us to say there is no place in our community for different kinds of people, but it's not right to leave that place as a slum."

City officials are scheduled to meet with developer Freeman tonight to discuss his plans. Realizing that it is impossible to relocate within Alexandria the estimated 3,000 to 5,000 tenants of the Layton Estate, city housing officers have said they will urge Freeman to phase in the renovation and help cover relocation expenses for tenants who cannot afford the new rents. By law, the developers are not bound to do either.

"I'm not complaining about my home," said Pacita Macias, a Dominion Gardens tenant listening carefully at the meeting yesterday. "It's not perfect, but we are glad to live here. Right now I don't know anywhere else to go."