Dec 16, 2015

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.”

Jacoba Charles
Associated Staff: 
Programs and Focus Areas: 
Clean Water Program
Bay Regional Monitoring Program
Contaminants of Emerging Concern