THREE young paperboys sit patiently outside the East St. Louis mayor's office, their legs dangling from chairs, paper sacks near their feet. They're here to give a message to Gordon Bush, the city's new mayor.Ushered into his office, they crowd around him. "There's prostitutes standing right down there," pipes up one boy, referring to one of the city's main streets. Another boy complains the police aren't taking care of the problem. "Police officers got to do right, too," he says. For Mayor Bush, a large man with a gentle voice and easy smile, such visits are common. In the nearly three months he's been in office, citizens young and old have called or come in to voice concerns or offer support. That support is badly needed. As mayor of one of the poorest and most troubled cities in the United States, he has what many consider the most difficult and challenging job of any city leader in the US and is seen as the last hope for reversing the city's three-decade economic decline. "I don't envy him his task," says Thomas Fitzsimmons, executive director of the Illinois Municipal League of Cities. "I hope something can be done, because right now it's a blight." Across the Mississippi River from the Gateway Arch and modern high rises of St. Louis, East St. Louis resembles a scarred ghost town in areas, with blocks and blocks of empty and burned-out houses. Unemployment hovers around 50 percent, the crime rate is one of the highest in the state, the city's debt is estimated at $50 million, and it has almost no tax base. East St. Louis hasn't always been regarded as an urban wasteland. In 1960 the US Chamber of Commerce honored it with an All-American city award. Stockyards and meat-packing plants were the main industry. Well-kept homes housed the mostly white, blue-collar workers. But after 1960 the plants began to close, some moving to the South, where labor was cheaper. Residents either migrated with them or remained here, unemployed. Between 1960 and 1990 the population plummeted from about 82,000 to a little under 4 1,000. Mayor Bush, a lifelong resident of East St. Louis with a master's degree in urban planning, is seen as a considerable improvement over Carl Officer, a funeral director who ran the city for the last 12 years. Under Mr. Officer, the city, already debilitated by mainly corrupt, white-led administrations, slid into further decline. The city's population now is about 90 percent black. With few resources, Bush has begun efforts to restore basic services other US cities take for granted. One such service is trash pickup. Several years ago, the fiscally strapped city stopped collecting trash. Unable to afford paying for private collection services, many residents either burn garbage in their yards or dump it where they can. City, county, and state officials are finalizing an estimated year-long trash cleanup plan that Bush says will begin in the next few weeks. Part of the money to finance the several-million-dollar project will come out of a $7 million community fund set up in January with fines from a fraudulent riverfront development project. "Making the town clean and safe are two things we must do and are in the process of doing," Bush says. A new police chief and five new police cars the state provided for an anti-drug unit have already helped eliminate some of the crime and crack-cocaine selling on the street. Another crisis the new mayor has temporarily resolved is irregular employee paydays. Often over the past two years, empty city coffers have meant sporadic paychecks. Bush has obtained a $3.75 million bailout loan from the state which will help pay employees through 1992. "That really caused a tremendous increase in the morale of employees," he says. "You can't expect a police and fire department and other municipal employees to go out and do a dynamic and inspired job when they're not getting paid." Bush's aides have been cleaning house and sifting through the last administration's sloppy record-keeping. The mayor estimates the city will retrieve nearly $1 million in uncollected fees from such sources as demolition of buildings, speeding tickets, and billboard advertising. Meanwhile, he is trying to attract industry to the area and says negotiations are under way with a number of businesses. He expects the city will have funds next year to start a riverboat gambling enterprise on the East St. Louis side of the river, a venture expected to generate $3 million to $4 million in revenue. Plans to further develop what many consider prime land along the weed-filled riverfront include proposals for a golf course, a mall, apartments, and a hotel. But some people say it will take more than determination and good management to turn the city around. "If you look to larger issues like how will they provide really adequate services and achieve some kind of economic development it becomes a much bigger question mark," says Charles Leven, a professor of economics at Washington University in St. Louis. "I can see real improvements going on through Gordon Bush in the sense that an impoverished population is probably going to be somewhat more comfortable than before. [But] it's not realistic to expect them to do very much without massive amounts of assista nce from the outside." Unlike Mayor Officer, who often shunned outside help, Bush is actively seeking it from county, state, and federal sources. So far, this is paying off. Housing and Urban Development funds which were taken away from the city under Officer because of poor management will be reinstated. Companies from around the area have offered trucks to help pick up trash. The United Way donated $20,000 to help reopen the city's swimming pools, and people in towns across the river sent checks. US Rep. Jerry Costello (D) of Illinois says Bush's willingness to cooperate with all levels of government is key to the city's success. "I think Mayor Bush is off to an excellent start. There are major differences between the previous administration and every indication as to how he will conduct his administration," he says. Bush says turning the city around will ultimately depend on the people. But he remains optimistic and determined: "I know how the city used to be, and I believe within my heart it can be equal to what it used to be and even greater. If I did not feel within myself that it were possible I wouldn't be here."