The D.C. City Council gave preliminary approval yesterday to a partial ban on the sale and use of phosphates in detergents and soaps sold in the District, bringing the city into line with the State of Maryland, whose ban on phosphates took effect Sunday.

The bill, which was passed unanimously, sets a $500 first-offense fine for selling cleaning products with phosphates and a $1,000 fine for subsequent offenses. Consumers who use such products would be subject to a fine of up to $15.

In other action, the council approved a $52 million revenue bond for George Washington University. Council Chairman David A. Clarke said the action was a late-year effort to move the bill through Congress before proposed tax reform bills limit the bond-issuing powers of local governments.

The phosphate prohibition, which does not include small quantities of phosphates used in dishwashers or for cleaning equipment employed in health care and food processing, was aimed at reducing pollution of the Chesapeake Bay and at cutting an estimated $1.5 million to $2 million in costs associated with removing phosphorus at the city's Blue Plains Wastewater Treatment Plant.

The only significant debate during first reading on the bill concerned the amounts of the fines. Council member Nadine P. Winter (D-Ward 6), sponsor of the legislation, proposed to set the consumer fine at $50 for the first offense and $100 for subsequent offenses, but member Polly Shackleton (D-Ward 3) pushed through an amendment lowering it to $15.

Council member Carol Schwartz (R-At Large) supported the lowered fine for persons using detergents but asked, "How are we going to enforce? Knock on people's doors and say, 'Let me see your detergent'?"

When Shackleton sought to lower the fine for sellers to $50, however, council member John Ray (D-At Large) protested that the amount was "a joke."

A "$1,000 fine is not all that much," said Ray. "A $50 fine is a joke. I don't know if the corporation counsel will even prosecute a $15 fine."

Shackleton withdrew her proposal after Hilda Mason (Statehood At Large) and Winter joined the criticism of the $50 seller's fine.

Winter, noting that "many of us are already using no-phosphate detergents without noticing a loss," read a telegram from Barry F. Scher, a spokesman for Giant Food Inc., in which Scher supported the phosphate ban.

"We phased out detergent products containing phosphates many months ago within our Maryland stores and to date we have not received one consumer complaint," the telegram said.

In previous council hearings on phosphates, which are present in many well-known products, including Tide and Cheer, debate on the merits of a ban centered on whether it would actually reduce pollution.

Charles Fox, the director of the Chesapeake Bay Project for the Environmental Policy Institute, testified that a 1983 U.S. Environmental Protection Agency Study showed that excessive phosphorus led to a sharp decline in submerged aquatic vegatation since 1971 and a decline in the number of finned fish and shellfish. Phosphates in large amounts, environmentalists say, trigger excessive growth of vegetation in lakes and bays. The vegetation dies, decaying and depleting the oxygen in the water.

Representatives of the detergent industry played down the likelihood of environmental benefits from the ban, however, contending that consumers would probably have to spend more money to clean their clothes.

Critics of the ban also have said that without a regional prohibition of phosphates, the ban in the District and Maryland would have limited value. Besides Maryland, six other states -- but not Virginia -- have prohibited phosphates.