Imports of silver into the United States fell sharply in 1987 to their lowest level in five years, according to preliminary statistics released by Handy & Harman, a major U.S. refiner of precious metals.

The firm said in its annual Review of the Silver Market for 1987, published Monday, that imports from traditional suppliers dropped 43.5 percent to 81.8 million ounces in 1987 compared to 144.9 million ounces in 1986.Significantly, supplies from Canada, the largest importer of silver into the United States next to Mexico, declined by more 50 percent in 1987 to 20.6 million ounces, which Handy & Harman's vice president and treasurer, Stephen B. Mudd, said reflected Canada's increased domestic needs to feed a growing industrial sector, estimated at 10.4 million ounces, or 8 percent higher than in 1986.

Mr. Mudd noted that the increase in Canadian coinage consumption by 1.2 million ounces to 3.2 million also may have kept more Canadian production at home. Canada's Calgary Olympic coin program began in late 1986 and ended in early 1988.

In fact, Canada exported some two million ounces of silver more in 1987 than in 1986 with about 700,000 ounces of that amount coming from the United States, the Handy & Harman report said.

The report also suggested that speculators and investors should continue to demand silver as a hedge against inflation this year. In 1987, said the report, investors worldwide increased their silver bullion holdings by 13 million ounces to 870 million ounces compared with a decline of 8.1 million ounces to 856 million ounces in 1986.

The company's Mr. Mudd said that there may well be some moderation in worldwide inflation, but there is little evidence that it will be brought under control.

He also said that the widespread lack of confidence in world currencies and international uncertainty will probably continue and may well intensify and create demand for gold and silver.