Pollution & Contaminated Fish


Every year, millions of pounds of toxic pollutants flow off roads, farms, and yards, and stream untreated into San Francisco Bay, where they can remain for decades.

Surrounded by hills and fed by creeks and rivers, our Bay acts like a giant bowl, collecting toxins and holding them. Toxic chemicals commonly found at alarming levels in the Bay include:

  • Mercury
  • Nitrates
  • Ammonia
  • Petroleum
  • PCBs

In addition, millions of gallons of trash are dumped into our Bay every year. That’s enough trash to fill 100,000 kitchen garbage bags.


Pollution has put the health of Bay fish and wildlife at serious risk. Scientific testing of fish in the Bay shows high levels of contamination with harmful chemicals like PCBs, PFOs, mercury, and pesticides. Some of these chemicals can keep fish from successfully reproducing, and many can be passed on to people and animals that eat the fish.

Studies show that marine mammals in the Bay, including harbor seals, exhibit some of the highest levels of PFOs in the world.  Birds that rely on Bay fish for their diet also show high levels of toxic chemicals.


In addition to harming fish and wildlife that live in and around the Bay, pollution poses direct threats to human health including:

  • Infections
  • Contagious disease
  • Impacts from ingesting Bay fish with high levels of mercury and carcinogenic chemicals

Unless we take action now to keep the Bay clean, these health threats will continue to build up in the Bay.


We have the knowledge and technology to stop the flow of pollution that contaminates the Bay. There are simple, low-cost solutions we can take all around the Bay that scientists and engineers confirm will have a huge impact on keeping the Bay clean.

We can start by restoring wetlands along the shoreline that provide natural filters to remove pollution from the water. We can also protect natural areas around the Bay to reduce the flow of toxic and polluted runoff.

Making the choice to put these solutions in place now will save us money over time and improve the health of the Bay. If we want our children and grandchildren to inherit a clean and healthy San Francisco Bay—one that will be part of their lives the way it is a part of ours—we need to act now.