Researchers in the three-year study said that these tiny particles, which are often microscopic, come from things like baby wipes flushed down toilets and synthetic fibers in clothing that contaminate waters when the clothing is washed. The study also found that a large portion of microplastics come from storm drains where particles from tire wear wash into the Bay.
All of the fish in the study tested positive for having consumed fibers, which are not necessarily made of plastic, but may be. Researchers said that even the fibers that are not plastic are from products produced by humans.
“While toxicological evaluation was not a part of this study, these results indicate that microplastics are entering Bay food webs,” the report stated. The report said that microplastics transfer up food chains, but more testing needs to be done to evaluate the effects that this may have on the environment.
The San Francisco Bay is more polluted than most other bodies of water because its narrow opening traps particles, according to the report.