Environment : Notes about your surroundings.

Cleaning Up--Upper Newport Bay will get a cleaning on Saturday, which the state has designated as Estuary Day. The state Fish and Game Department and the county, the city of Newport Beach and Friends of Newport Bay are sponsoring the cleanup drive.

Volunteers will join members of the California Conservation Corps in removing debris from reeds, marshes, roads and trails without disturbing the habitat, which supports a variety of wildlife.

There will be two shifts. The first begins at 9 a.m.; the second, at noon. Food and beverages will be provided.

Back Bay Drive will be closed to vehicular traffic from 8 a.m. to 4 p.m. to facilitate the cleanup. Canoe clubs are encouraged to participate, and motorized vessels may enter Upper Newport Bay to aid in the task.

Guided tours of the reserve and lectures will be offered. For information, call John Scholl at (714) 640-6746 or Tim Miller at (714) 567-6200.

Symposium--The Natural History Foundation of Orange County has announced the schedule for its fourth annual Natural History Symposium on Nov. 19 at the Nelson Research Building at UC Irvine.

“Global Pollution and Local Action” will be the title of the symposium. F. Sherwood Rowland of the UCI chemistry department will speak on “Stratospheric Ozone Depletion.” Rowland and his associates were the first to demonstrate the connection between the release of chlorofluorocarbon gases and depletion of the Earth’s protective ozone layer.

Other topics will include “A Call to Action: Recent Activities in Irvine,” “The Greenhouse Effect and Anticipated Climate Changes,” “The Planet Earth’s Imperiled Waters” and “Remediation of Contaminated Soils and Water: A Case History--Kesterson Reservoir.”

Admission is $3 for students, $6 for others. For information, call (714) 640-7120.