While being videotaped from a helicopter, 50 teams of five competitors each will race through the heart of southern Utah's canyon country this April. Although 85 percent to 90 percent of the 700 comments received opposed the scheme, the Bureau of Land Management recently gave its approval, with conditions, to the Eco-Challenge race, a 10-day, 370-mile romp across public lands. Organizers say it will provide an environmentally correct, low-impact message. Critics wonder how that's possible, since the race will continue both day and night, and will receive coverage by a national press not subject to the same restrictions as participants. They charge that the BLM never considered avoiding wilderness study areas, peregrine falcon aeries or bighorn sheep habitat. The competitors will hike, run, bike, climb, ride and paddle from Huntington, south of Price in central Utah, to Bullfrog Marina on Lake Powell. The BLM has required that the sponsor put up an $80,000 bond to cover clean-up expenses and that the race course follow roads and wash-bottoms so that, according to the BLM District Manager Kate Kitchell, impacts "will be short-term and small-scale." Opponents, including local guides, outfitters and environmentalists, have appealed the BLM's decision; a decision is expected before April 25.