It's quiet on the South Fork of the Shenandoah these days. Even 62-year-old Wilson Kite, who has fished this river "since I was old enough to hold a pole," took the week off.

The people in the hardscrabble towns of Grottoes and Port Republic, Elkton, Stanley and Luray, the serious fishermen from Washington and points even farther away, aren't testing their luck on the swift, brown-green waters.

Twenty-seven years ago, the duPont plant in Waynesboro stopped using mercury in its production of acetic anhydride. Five days ago, Virginia Gov. Mills Godwin told anglers to stop eating fish from the South Fork and two other streams because the fish were loaded with the poisonous metal.

No state officials are willing to say so flatly, but indications are that the mercury discovered in the fish this spring is mercury that come from the duPont plant in 1950 and before.

"There is no known source besides duPont," said Michael Bellanca of the state Water Control Board. "We are looking now to determine other potential sources . . ."

It was duPont that first discovered the danger. Construction workers digging up and old loading dock in April found deposits of metallic mercury in the ground.

They called in company environmental specialists, who checked further and found mercury contamination in fish and sediments in the adjacent South River. DuPont reported its findings to the state Water Control Board.

The WCB set up 15 checking stations, mostly downstream on the South River and the river it feeds, the South Ford of the Shenandoah.

Within two months, the WCB had evidence of enough mercury in game fish to recommend a ban on eating the fish. Godwin's order followed on Monday.

The closure does not end fishing, but it does make taking fish for human comsumption a misdemeanor punishable by fines of up to $10,000, according to Dr. Robert Jackson, assistant state health commissioner. Jackson said such fines are unlikely.

"Our responsiblility is to warn the people of the danger and let them know we think it's important enough to make it illegal," he said.

The ban extends from the South River bridge just below the duPont plant in Waynesboro downstream to the head of the South Fork of the Shenandoah. It runs the entire length of the South Fork and onto the main body of the Shenandoah to the Riverton power pool just below Front Royal.

In all, it is illegal to eat fish caught on about 129 miles of river. The real rub for sporting anglers in the South Fork ban.

Jack Lorenz,, National director of the Izaak Walton League, put it this way: "One of the reasons I moved to Washington was to fish the Shenandoah. I have a spot where I can catch 50 small mounth every time I go out. Nothing is more important to us than the Shenandoah. I love that river."

Lorenz said the Virginia Division of the Izaak Walton League will meet in Blacksburg this weekend to map plans for dealing with the mercury problem.

It means something even dearer to Kite, who has lived on the South Fork all his life. He runs a store and campground on the riverbank halfway between the towns of Shenandoah and Stanley and has float-fished the river for 50 years.

"There's just too much of this stuff going on that don't turn out what it seems to be," he growled. "If it's true, why I'd been dead long ago. I don't believe anybody eats more fish than I eat fish three or four times a week."

The Walter Control Board took samples of fish by electroshocking sections of the river and scooping out samples. Scientists found concentrations of up to 2.10 parts per million of the heavy metal in the fish meat. The Environmental Protection Agency has established .5 ppm as the level above which human consumption is dangerous.

The highest concentrations of mercury were in so-called predator fish - smallmouth, largemouth and rock bass - which are at the top of the food chain. But unsafe levels also were detected in bottom feeders and sunfish, including blue gills.

Generally, the levels were highest in the checking stations from just below Waynesboro downstream to Luray. Checks below Front Royal on the main Shenandoah streambed showed generally safe levels.

The WCB also ran checks on mercury levels in the sediments of the streambed. Results are not tabulated yet. The ban extends until Sept. 30 and the sediment tests should help determine whether it will be extended at that time.

A Virginia river was closed to fish-taking once before due to mercury contamination. It was the North Fork of the Holston in the southwest corner of the state. Mercury levels similar to those in the Shenandoah were found in the Holston before it was put on the banned list in 1970, according to the Water Control Board's Bellance. Fishing for human consumption is still banned there.