The U.S. Geological Survey released a report summarizing suspended solids concentrations in the San Francisco Bay from October 1997 through September. Suspended solids, which are sediments and organic matter moving in the bay water, are important because they transport adsorbed contaminants such as metals and pesticides, provide the habitat for benthic organisms, limit light availability and photosynthesis, and deposit in ports and shipping channels, which require dredging. The suspended-solids concentration data will be used by the U.S. Geological Survey to determine the factors that affect suspended-solids concentrations in San Francisco Bay and to help develop numerical models of the bay. Suspended solids concentrations were measured at Mallard Island, Benicia Bridge, Golden Gate Bridge, Point San Pablo, San Francisco Pier 24, San Mateo Bridge, Dumbarton Bridge, and at a channel marker south of Dumbarton Bridge. Measurements were collected every 15 minutes from optical sensors positioned at mid-depth and near the bottom of the bay.