What was going on when I was born?

The United States said today that it had expelled the senior military attache in the Soviet Embassy here on espionage charges. A State Department spokesman, Sondra McCarty, said in response to an inquiry that the attache, Maj. Gen. Vasily I. Chitov, had been declared persona non grata and had left Wednesday. Asked the reasons for the expulsion, Mrs. McCarty said on ly that the attache had been expelled ''for activitie s inconsistent with his diplomatic status.''

SOUTH STREET, once the heart of seafaring New York, is a lot more these winter weekends than just a place to visit ships - although the climb up the gangway is always worth making. This weekend, for instance, without once leaving terra firma, you can attend an oldfashioned Sunday reading of the great American sea novel, ''Moby-Dick,'' take a tour down 18th-century streets, browse for book bargains, get a card for your Valentine hot off the press and warm your shivering timbers with hot grog. For the first few pages of ''Moby-Dick,'' Herman Melville's pensive hero, Ishmael, has the blues. To cure them, he sets off to sea, starting by way of the South Street Seaport, a bustling neighborhood of shops, saloons and boardinghouses. This weekend offers an ideal opportunity to follow Ishmael's trail through the southeast tip of Manhattan and to see many of the buildings that remain from his time. Moreover, on Sunday, in the spacious Seaport Gallery at 213-215 Water Street, four professional actors will present a dramatic reading from ''Moby-Dick.'' They hope that Melville's prose will carry the day, but they'll also spice up a few passages - like the detailed descriptions of rigging sails - by using the gallery's impressive sailing-ship models as props.

Despite one of the worst cold spells in memory, demand for home heating oil and other petroleum products has weakened substantially, dropping prices sharply in the past 10 days. Oil traders report that prices for crude oil and heating oil on the spot market, where oil that is not under long-term contract is traded, have dropped by more than 5 percent, after having held relatively steady for several months. A similar trend is becoming evident for gasoline prices. Putting Pressure on OPEC The sharp drop puts heavy pressure on the Organization of Petroleum Exporting Countries and other oil producers to reduce their official contract prices, as some have quietly begun to do through disguised discounts.

Leonard H. Marks, a former director of the United States Information Agency, was elected chairman of the Foreign Policy Association yesterday. Mr. Marks, a Washington lawyer, who has been vice chairman since 1979, succeeds Carter L. Burgess as head of the association's 75-member board of governors. Mr. Burgess, the chairman since 1974, is to become head of the board's executive committee.

The Senate today approved a proposal that could virtually eliminate busing as a tool for racial integration of the public schools. The proposal drew strong support from both parties and passed by a vote of 58 to 38, a sign that busing had become highly unpopular in many communities. The measure would bar the Federal courts from ordering busing plans that transport schoolchildren more than five miles from home or take longer than 15 minutes. It would also allow the Justice Department to ask the courts to overturn existing busing plans that exceed these limits.

President Reagan announced today that the United States had presented the Soviet Union with a draft treaty that proposed the elimination of medium-range nuclear missiles in Europe. The draft treaty, which is based on the ''zero option'' plan endorsed by Mr. Reagan over two months ago, was introduced on Tuesday during the negotiations on limiting medium-range nuclear arms in Europe, according to a White House spokesman. Those talks began last November in Geneva. ''I call on President Brezhnev to join us in this important first step to reduce the nuclear shadow that hangs over the peoples of the world,'' Mr. Reagan said in a statement released today by the White House.

''The notion that anybody has been misled, anybody has been deceived, anything has been rigged, is absolutely and utterly without foundation.'' - Mr. Stockman. (A18:5.)

In the last 10 years, executives in such industries as forest products, steel, tires and oil turned to petrochemicals to get in on the the fast-growth business of plastics. The popularity of plastics, however, has turned into a classic case of too many merchants selling the same wares, any many producers are finding it difficult to make a profit. The competition moved the Cities Service Company just two weeks ago to write off the cost of a $300 million polyethylene plant that was 20 percent co mpleted. And Dow Chemical has ''indefinitely'' shelved plans for a n ew polystyrene plant.

NEW YORK is an opera town: two major companies, important new productions, a host of world-famous singers and an army of eager fans attest to that. But another, perhaps even more telling sign of the importance of opera for the city is the number of smaller companies that offer unusual repertory, ambitious young singers, low ticket prices and intimate settings that sometimes convey operatic drama better than a larger house could ever do. This weekend the Metropolitan Opera is presenting such honorable but familiar staples as ''La Boheme,'' ''Il Trovatore'' and ''Cosi fan tutte.'' The New York City Opera is still in its winter break. But opera lovers can still see and hear works as varied as Giovanni Pacini's ''Saffo'' -which is believed to have had its last American performance in 1866 - Puccini's ''La Rondine,'' a Mozart double bill of ''Bastien and Bastienne'' and ''The Impresario,'' Gilbert and Sullivan's ''The Mikado,'' a double bill of William Walton's ''The Bear'' and Jack Beeson's ''Hello Out There,'' a chamber opera by Mira J. Spektor called ''Lady of the Castle'' that is based on an Israeli play, and a program of no less than five short contemporary operas by lesser-known composers.

The Treasury sold new 14 percent bonds yesterday at an average yield of 14.56 percent, a record for a new 30-year issue that showed the extreme reluctance of investors to buy long-term bonds even though inflation has subsided. The high yield for the bonds - up from only 13.9 percent a week ago and 12 3/4 percent in late November -seemed to confirm Wall Street warnings that large budget deficits push up interest rates. Early last November, the Treasury sold similar bonds at a 14.10 percent yield, but since then budget deficit estimates for the fiscal years 1983 and 1984 have expanded sharply. Despite this, Treasury officials had little choice but to crowd into the credit markets this week with $20 billion of short- and long-term issues that raised about $6.7 billion of new cash. Treasury officials estimated last week that they needed to raise $41.25 billion of new cash this quarter to cover a fiscal 1982 deficit estimated by private analysts and some Government officials at $100 million.

When Betty Jane Scheihing was on the witnessstand Wednesd ay in Westchester County Court here, she spoke crisply, directly and seemingly without emotion in describing how she saw the earliest mome nts of the fire that killed 26 executives at Stouffer's Inn on Dec. 4 , 1980. But by afternoon the court saw a different Mrs. Scheihing recalling the same events, under hypnosis, in a session videotaped last February. She spoke more quietly from the screen than she had in person, pausing longer before answering and differing in some important details. And at one point, under hypnosis, she broke into tears. Mrs. Scheihing, who is director of field operations at the Arrow Electronics Corporation of Greenwich, Conn., was one of three witnesses to the fire who were voluntarily hypnotized to aid their memories at the request of investigators. The investigators have since charged Luis Marin, a 26-year-old Guatemalan coffee waiter, with arson and murder.

Interest rates and fees paid by individuals for banking services are rising dramatically as banks across the country try to make more money on their retail services or reverse losses. Even as interest rates have declined for big corporations and financial institutions over the past half year, rates have been rising for consumers. Just last week, for example, the Manufacturers Hanover Trust Company announced that the interest rate on its credit card loans would rise by 10 percent, to 19.8 percent from 18 percent, effective March 1. Over all, the effective cost of most consumer-banking services is being shifted from those who maintain large deposit balances to people with smaller accounts, who bankers contend have not paid the full cost of service. And some bankers are questioning whether individuals with only a few hundred dollars of savings belong in the banking system at all.