The refuges created to protect America's dwindling wildlife population face more than 7,000 environmental problems, ranging from litter to contaminated waterways, according to an Interior Department report.

The problems affect virtually every natural resource the refuges are supposed to preserve, the report said. More than half of Interior's 417 refuges report problems with air and water pollution, poaching, soil erosion and wildlife disturbance. Waterfowl face threats on 318 refuges; migratory birds are in trouble on 313.

More than half of the threats come from outside, such as acid rain, pollution from mining and drilling, and development pressures from "special-interest groups," according to the report. But 42 percent of the cited problems are internal, such as grazing, farming, logging, the use of toxic herbicides and pesticides, littering and run-down facilities, according to documents collected for the report.

Robert A. Jantzen, director of Interior's Fish and Wildlife Service, cautioned that the report "could be misleading" because it does not indicate how serious each problem is. While 261 refuge managers reported littering as a problem, he said, "we know it poses no serious threat to wildlife refuges."

Jantzen also said that many of the problems are being corrected. But conservationists said that the report raises serious questions about Reagan administration policies.

Jantzen recently instructed refuge managers to expand such "public and economic use" of the refuges as lumbering, grazing, farming, haying, concessions and oil and gas extraction. Interior recently adopted regulations that could allow oil and gas leasing on up to 1 million acres of refuge lands if Fish and Wildlife officials find it "compatible" with protecting wildlife.

The report reached no conclusions about the overall threat to the refuges, but a draft of the report said, "These threats will continue to degrade certain fish and wildlife resources until such time as mitigation measures are implemented."