page_title: San Francisco Bay
section_title: Pollution
hierarchical_section_title: San Francisco Bay / Pollution
caption_attribution_description: العربية: جسر فوج باي وجسر البوابة الذهبية وسان فرانسيسكو في الضباب English: Low fog at the Bay Bridge, Golden Gate Bridge, and San Francisco.
context_page_description: San Francisco Bay is a shallow estuary in the US state of California. It is surrounded by a contiguous region known as the San Francisco Bay Area, and is dominated by the large cities of San Jose, San Francisco and Oakland.
  San Francisco Bay drains water from approximately 40 percent of California. Water from the Sacramento and San Joaquin rivers, and from the Sierra Nevada mountains, flow into Suisun Bay, which then travels through the Carquinez Strait to meet with the Napa River at the entrance to San Pablo Bay, which connects at its south end to San Francisco Bay. It then connects to the Pacific Ocean via the Golden Gate strait. However, this entire group of interconnected bays is often called the San Francisco Bay. The bay was designated a Ramsar Wetland of International Importance on February 2, 2012.
context_section_description: Industrial, mining, and other uses of mercury have resulted in a widespread distribution in the bay, with uptake in the bay's phytoplankton and contamination of its sportfish. In January 1971, two Standard Oil tankers collided in the bay, creating an 800,000-U.S.-gallon (3,000,000-liter) oil spill disaster, which spurred environmental protection of the bay. In November 2007, a ship named COSCO Busan collided with the San Francisco–Oakland Bay Bridge and spilled over 58,000 U.S. gallons (220,000 liters) of bunker fuel, creating the largest oil spill in the region since 1996.
  The Bay was once considered a hotspot for polybrominated diphenyl ether (PBDE) flame retardants used to make upholstered furniture and infant care items less flammable. PBDEs have been largely phased out and replaced with alternative phosphate flame retardants. A 2019 San Francisco Estuary Institute (SFEI) study assayed a wide range of these newer flame retardant chemicals in Bay waters, bivalve California mussels (Mytilus californianus), and harbor seals (Phoca vitulina) which haul out in Corkscrew Slough on Bair Island in San Mateo County, with phosphate flame retardant contaminants such as tris(1,3-dichloro-2-propyl)phosphate (TDCPP) and triphenyl phosphate (TPhP) found at levels comparable to thresholds for aquatic toxicity.
caption: City skyline through the fog, from the Golden Gate National Recreation Area.
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