Scientist: Ban on two-stroke engines may not quench threat

Wednesday, March 31, 1999 | 9 a.m.

James Oris said marine engines not immediately covered by the Tahoe Regional Planning Agency's order still could threaten fish and zooplankton.

Oris, a researcher from Miami University in Oxford, Ohio, said both fish and the microscopic animals can be harmed when sunlight combines with gasoline emissions in water, producing the biologic equivalent of a bad sunburn.

"Is the issue dead? I'm telling you I don't think so," he said at a gathering at the University of Nevada, Reno, on the overall health of the lake in the face of ongoing pollution from gas engines.

While the bi-state agency's coming regulations may remove the worst-polluting engines at the lake, Oris said harmful hydrocarbons still will be deposited by cleaner-burning two-stroke engines and the four-stroke plants.

"It's not going to make much difference," he said Monday. "I don't think the concentrations are going to change much as you phase in this new type of engine."

UNR's Glen Miller, interim director of the university's Center for Environmental Scientists and Engineering, said the groups will be cooperating with another study this summer. UNR has secured $25,000 to fund additional research.

Oris said his research, of water samples collected off Tahoe City Marina and from two miles offshore, found that as sunlight increased, fish growth diminished and the zooplankton population dwindled.

"What kills fish isn't bad sunburn on their skin, it's bad sunburn on their gills," he said.