More than 70 percent of the persons arrested since January for buying illegal pills from undercover D.C. policemen are whites and suburbanities, indicating that outsiders and commuters are active participants in the thriving drug traffic in some of the city's black neighborhoods, according to D.C. police records.

Since Jan. 22, as part of an operation dubbed "Bamscam," undercover officers posing as drug dealers near the intersection of Ninth and O streets NW have arrested 71 persons trying to buy Preludin -- known as "bam" in street slang -- and Dilaudid. Both are diet pills used as herion boosters or heroin substitutes.

Of those arrested, 51 have been whites, 19 black and one Asian, according to police records. Twenty-six of those taken into custody said they lived in Maryland, 24 in Virginia, one in New York, and the remaining 20 were D.C. residents, police said.

"Commuters are responsible for 50 percent of the city's pill traffic," said Inspector Wilfred K. Coligan, head of the morals division. "If we can cut down on the commuters, it would have a very definite impact on the drug traffic in D.C."

Drug investigators say millions of dollars worth of Preludin and Dilaudid are sold on the city's streets. "It's a very big business," said Sgt. Ramon Gonzalez.

Gonzalez estimates that some dealers of the pills make as much as $2,000 a day profit. A Dilaudid pill, which is about the size of an asprin, is available by prescription for about 13 cents in the pharmacy but sells for as much as $35 to $40 on the street. Some dealers sell as many as 100 to 150 tablets per day, he said.

Although heroin is considered more dangerous, Gonzalez said Dilaudid "is stronger than some of the heroin on the streets."

Heroin and cocaine have been the primary targets of D.C. police. But, Gonzalez said the pills illegally sold on the street are just as plentiful as heroin and pill busts frequently do not bring such stiff sentences in court.

Gonzalez said he believe the majority of those arrested were using it as a substitute for heroin. "None of these people would you call low income," Gonzalez added. "The biggest majority are middle class."

They have included car salesmen, secretaries, receptionist, computer technicians, members of the Armed Forces, painters, plumbers, insurance salesmen, bartenders, hairdressers, carpenters, construction workers, and clerks, according to police records.

"D.C. is a ready market place," said Coligan. "In Virginia or Maryland, unless you know the people you can't buy it. In D.C., they sell to everybody."

Undercover narcotics detectives assigned to the "Bamscam" operation stand among crowds of drug dealers waiting to be approached by potential buyers.

Interested customers either hold up four fingers for Dilaudid, which sold in 4-milligram tablets, or shout "pinks" for the pink preludin pills. Other officers than converge and arrest the buyer.

Undercover detective Freddy Lawson said he has had no problem getting customers. "Most of the dealers that hang around the corner know me and know I'm with the police. When I show up, they just step back and watch. They don't even warn the buyers. All I have to do is stand there," he said.

Three of those arrested had young children in the car when the police nabbed them, police said. A couple of persons driving their company trucks have been arrested and their company trucks seized until the owner could come and claim it.

One white man from Northern Virginia paid for two Dilaudid tablets with $20 worth of food stamps. The man later told the officer that he generally sells his food stamps in the grocery store, but had been unable to do that on this day. One man offered the undercover officer a bottle of Valium and $51 for two Dilaudid tablets.

On Friday, the undercover operation netted 16 arrests -- nine blacks and seven whites. One of those arrested was a Maryland woman who had placed a call earlier to a nearby telephone booth, looking for another dealer. The undercover officer answered the phone and the woman placed an order for three Dilaudid tablets.

Thirty minutes later, she arrived, bought the tablets and was arrested.

"We want to discourage the customer," said Sgt. Alfred L. Boyd. "We want them to know that wherever they might be buying drugs, they might be buying from an undercover officer."

Although the operation thus far has been concentrated in the 9th and O streets corridor, officials say they plan to expand to other drug areas in the city.

D.C. Police Chief Maurice T. Turner said the large proportion of whites and suburbanities arrested in Washington shows that "there is a dependence out there also," which contributes to what he considers the city's No. 1 crime problem -- drug abuse.

"There's a drug epidemic in this city. . . The drugs are plentiful and cheaper. I think we have a new generation of addicts. . . People are going to rob, they will steal, they will burglarize to support their dependency. I believe that has pushed our crime rate up 50 percent."