December's issue of Estuary News features an article, "Unhealthy Fiber in Bay Diet," that highlights the surprising result of a preliminary study of Bay microplastic pollution, which suggested that San Francisco Bay has higher levels of microplastic than other major urban waterbodies in the US for which data are available. Using nets and sieves designed to capture very small particles, scientists with the Regional Monitoring Program for Water Quality in San Francisco Bay filtered samples of Bay surface water and wastewater treatment plant effluent. Samples were then visually inspected to identify and count each and every plastic particle. The RMP has developed a fact sheet with the study results.
Fibers were the most common type of microplastic particle in treated wastewater. These particles are often created by laundering polyester and other synthetic fabrics. Other types of microplastic pollution include microbeads derived from personal care products, and small particles that have broken down from larger plastic litter.
Jacoba Charles' article outlines the main toxicological concerns relating to microplastic pollution. "Wildlife and other creatures can mistake the tiny particles for food," writes Charles. "Additionally, microplastics have been found to preferentially adsorb toxic pollutants such as pesticides, dioxins, flame retardants, and PCBs."
Finally, the article emphasizes one practical solution—discontinued use of consumer products that are known to be sources of microplastics in wastewater. According to Karin North, Watershed Protection Manager at City of Palo Alto, which operates one of the more sophisticated treatment plants in the Bay Area, “upgrading the plants would cost taxpayers billions—multiple billions—of dollars… If you can remove it at the source, it’s always better than trying to clean it up at the treatment plant.”
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The RMP has conducted initial studies of microplastic pollution in San Francisco Bay. Findings from a 2015 screening-level RMP study of microplastic pollution in our Bay show widespread contamination at levels greater than other U.S. water bodies with high levels of urban development, the Great Lakes and Chesapeake Bay. Wildlife consume microplastic particles; ingestion can lead to physical harm, and can expose aquatic organisms to pollutants like PCBs that the plastics have absorbed from the surrounding environment.
The same week that the U.S. House of Representatives passes a bill to ban microbeads in cosmetic products, the Bay's Regional Monitoring Program releases a fact sheet that describes our recent study on microbeads and other microplastic particles in Bay water and treated wastewater.
In the wake of the passage of the microbead ban, KQED released a story about it's potential hazards. As a science resource, Dr. Rebecca Sutton lent her expertise: "'Municipal wastewater systems were designed for our [bodily] waste and food waste, but they’re not engineered to handle tiny bits of plastics,' said Rebecca Sutton of the San Francisco Estuary institute. Upgrading waste treatment facilities to handle microbead waste would cost billions, and it wouldn’t necessarily be effective."
Rebecca Sutton, senior scientist at SFEI, describes the hazards presented by microplastics in the Bay's waters. "Plastic pollution: Billions of pieces of tiny plastic litter found in San Francisco Bay," a news article by Paul Rogers reports on findings in a recently published study for which Rebecca Sutton serves as lead author. What the researchers discovered, the high degree of plastic contamination, surprised them.
Last week, the Governor signed AB 888, a bill that bans microplastic beads in personal care products. Companies have until 2020 to phase out the use of these "microbeads." California now has strongest state law in the nation on this issue.
SFEI science played a key role in informing policymakers about microbeads and microplastic pollution. Media stories on a Regional Monitoring Program study of microplastics in San Francisco Bay water and treated wastewater broadcast the latest findings to a wide audience. The study indicated that our Bay had higher levels of microplastic pollution than the Great Lakes and Chesapeake Bay. Clearly identifiable microbeads derived from personal care products were detected at all nine sites examined in San Francisco Bay.