San Diego County's environmental health department closed the San Diego Tijuana Slough shoreline in southern San Diego County on Friday, cautioning people against coming into contact with the ocean water.
The Tijuana River enters San Diego County from Mexico and flows through the southernmost part of the county before it empties into the Pacific Ocean.
Sewage-contaminated runoff that enters the river in Mexico may be moving north along the San Diego County shoreline, according to a statement Thursday from the San Diego County Department of Environmental Health and Quality.
The "water contact closure" issued Thursday covers the ocean shoreline at Tijuana Slough National Wildlife Refuge and Border Field State Park and results from bacterial counts in samples taken by the county exceeding California health standards.
Get top local stories in San Diego delivered to you every morning. Sign up for NBC San Diego's News Headlines newsletter.
It includes all beaches from the international border to the south end of Seacoast Drive in Imperial Beach. Closure signs will remain in place until daily ocean water sampling results meet state health standards for recreational use, county officials said.
Officials also issued a "precautionary advisory" for the rest of the Imperial Beach shoreline on Thursday due to non-river-related impacts, including a south swell. They also issued an advisory for Moonlight Beach at Cottonwood Creek in Encinitas due to the potential for bacteria counts to exceed health standards.
That means county officials suggest beachgoers "avoid water contact in the advisory area."
Beaches in southern San Diego County have been closed off and on all year.
More information about the Tijuana River is available by calling the U.S. International Boundary & Water Commission at (619) 662-7600.
Updates from San Diego County on beach closure information are available online. Residents also may call the 24-hour hotline at (619) 338-2073.
