Understanding Microplastic Levels, Pathways, and Transport in the San Francisco Bay Region. SFEI Contribution No. 950. San Francisco Estuary Institute: Richmond, CA.2019.
Microplastics (particles less than 5 mm) are ubiquitous and persistent pollutants in the ocean and a pervasive and preventable threat to the health of marine ecosystems. Microplastics come in a wide variety of shapes, sizes, and plastic types, each with unique physical and chemical properties and toxicological impacts. Understanding the magnitude of the microplastics problem and determining the highest priorities for mitigation require accurate measures of microplastic occurrence in the environment and identification of likely sources.
To develop critical baseline data and inform solutions, the San Francisco Estuary Institute and the 5 Gyres Institute have completed the first comprehensive regional study of microplastic pollution in a major estuary. This project supported multiple scientific components to develop improved knowledge about and characterization of microparticles and microplastics in San Francisco Bay and adjacent National Marine Sanctuaries, with the following objectives:
- Contribute to the development and standardization of sample collection and analysis methodology for microplastic transportation research.
- Determine a baseline for future monitoring of microplastics in San Francisco Bay surface water, sediment, and fish, and in ocean waters outside the Golden Gate.
- Characterize pathways by which microplastics enter the Bay, including urban stormwater and treated wastewater effluent.
- Investigate the contribution of Bay microplastics to the adjacent National Marine Sanctuaries through computer simulations.
- Communicate findings to regional stakeholders and the general public through meetings and educational materials.
- Facilitate evaluation of policy options for San Francisco Bay, with recommendations on source reduction.
This document presents the findings of this three-year project. A companion document, “San Francisco Bay Microplastics Project: Science-Supported Solutions and Policy Recommendations,” has been developed by 5 Gyres using the findings of this study (Box and Cummins, 2019).
Contaminants of Emerging Concern in San Francisco Bay: A Strategy for Future Investigations 2018 Update. SFEI Contribution No. 873. San Francisco Estuary Institute: Richmond, CA.2018.
Per and Polyfluoroalkyl Substances (PFAS) in San Francisco Bay: Synthesis and Strategy. SFEI Contribution No. 867. San Francisco Estuary Institute : Richmond, CA.2018.
Contaminants of Emerging Concern in San Francisco Bay: A Strategy for Future Investigations. 2017 Revision. SFEI Contribution No. 815. San Francisco Estuary Institute: Richmond, CA.2017.
Microplastic Monitoring and Science Strategy for San Francisco Bay. SFEI Contribution No. 798. San Francisco Estuary Institute: Richmond, Calif.2017.
Per- and polyfluoroalkyl substances (PFAS) in San Francisco Bay wildlife: Temporal trends, exposure pathways, and notable presence of precursor compounds. Chemosphere 185, 1217-1226 . SFEI Contribution No. 839.2017.
Sampling and Analysis Plan for Microplastic Monitoring in San Francisco Bay and Adjacent National Marine Sanctuaries. SFEI Contribution No. 819. San Francisco Estuary Institute: Richmond, CA.2017.
Poly- and perfluoroalkyl substances in wastewater: Significance of unknown precursors, manufacturing shifts, and likely AFFF impacts. Water Research . SFEI Contribution No. 780.2016.
In late 2014, wastewater effluent samples were collected from eight treatment plants that discharge to San Francisco (SF) Bay in order to assess poly- and perfluoroalkyl substances (PFASs) currently released from municipal and industrial sources. In addition to direct measurement of twenty specific PFAS analytes, the total concentration of perfluoroalkyl acid (PFAA) precursors was also indirectly measured by adapting a previously developed oxidation assay. Effluent from six municipal treatment plants contained similar amounts of total PFASs, with highest median concentrations of PFHxA (24 ng/L), followed by PFOA (23 ng/L), PFBA (19 ng/L), and PFOS (15 ng/L). Compared to SF Bay municipal wastewater samples collected in 2009, the short chain perfluorinated carboxylates PFBA and PFHxA rose significantly in concentration. Effluent samples from two treatment plants contained much higher levels of PFASs: over two samplings, wastewater from one municipal plant contained an average of 420 ng/L PFOS and wastewater from an airport industrial treatment plant contained 560 ng/L PFOS, 390 ng/L 6:2 FtS, 570 ng/L PFPeA, and 500 ng/L PFHxA. The elevated levels observed in effluent samples from these two plants are likely related to aqueous film forming foam (AFFF) sources impacting their influent; PFASs attributable to both current use and discontinued AFFF formulations were observed. Indirectly measured PFAA precursor compounds accounted for 33%–63% of the total molar concentration of PFASs across all effluent samples and the PFAA precursors indicated by the oxidation assay were predominately short-chained. PFAS levels in SF Bay effluent samples reflect the manufacturing shifts towards shorter chained PFASs while also demonstrating significant impacts from localized usage of AFFF.
The Regional Monitoring Program for Water Quality in San Francisco Bay, California, USA: Science in support of managing water quality. Regional Studies in Marine Science 4.2016.
The Regional Monitoring Program for Water Quality in San Francisco Bay (RMP) is a novel partnership between regulatory agencies and the regulated community to provide the scientific foundation to manage water quality in the largest Pacific estuary in the Americas. The RMP monitors water quality, sediment quality and bioaccumulation of priority pollutants in fish, bivalves and birds. To improve monitoring measurements or the interpretation of data, the RMP also regularly funds special studies. The success of the RMP stems from collaborative governance, clear objectives, and long-term institutional and monetary commitments. Over the past 22 years, high quality data and special studies from the RMP have guided dozens of important decisions about Bay water quality management. Moreover, the governing structure and the collaborative nature of the RMP have created an environment that allowed it to stay relevant as new issues emerged. With diverse participation, a foundation in scientific principles and a continual commitment to adaptation, the RMP is a model water quality monitoring program. This paper describes the characteristics of the RMP that have allowed it to grow and adapt over two decades and some of the ways in which it has influenced water quality management decisions for this important ecosystem.
Contaminants of Emerging Concern in San Francisco Bay: A Strategy for Future Investigations. 2015 Update. Contaminants of Emerging Concern in San Francisco Bay: A Strategy for Future Investigations. SFEI Contribution No. 761. San Francisco Estuary Institute: Richmond, CA.2015.
About this Update
The Regional Monitoring Program for Water Quality in San Francisco Bay (RMP) has been investigating contaminants of emerging concern (CECs) since 2001. CECs can be broadly defined as synthetic or naturally occurring chemicals that are not regulated or commonly monitored in the environment but have the potential to enter the environment and cause adverse ecological or human health impacts.
The RMP Emerging Contaminants Workgroup (ECWG), established in 2006, includes representatives from RMP stakeholder groups, regional scientists, and an advisory panel of expert researchers that work together to address the workgroup’s guiding management question – Which CECs have the potential to adversely impact beneficial uses in San Francisco Bay? The overarching goal of the ECWG is to develop cost-effective strategies to identify and monitor CECs to minimize impacts to the Bay.
To this end, the RMP published a CEC Strategy document in 2013 (Sutton et al. 2013). The strategy is a living document that guides RMP special studies on CECs, assuring continued focus on the issues of highest priority to the health of the Bay. A key focus of the strategy is a tiered risk and management action framework that guides future monitoring proposals. The strategy also features a multi-year plan indicating potential future research priorities.
This 2015 CEC strategy update features revised designations of CECs in the tiered risk and management action framework based on monitoring and research conducted since 2013. Brief summaries of relevant RMP findings are provided. In addition, a proposed multi-year plan for future RMP Special Studies on CECs is outlined. A full revision of the CEC strategy is anticipated in 2016.
Declines in Polybrominated Diphenyl Ether Contamination of San Francisco Bay following Production Phase-Outs and Bans. Environmental Science and Technology 49 (2), 777-784 . SFEI Contribution No. 742.2015.
Polybrominated Diphenyl Ethers (PBDEs) in San Francisco Bay: A Summary of Occurrence and Trends. SFEI Contribution No. 713. San Francisco Estuary Institute: Richmond, CA. p 62.2014.
Contaminants of Emerging Concern in San Francisco Bay: A Strategy for Future Investigations. San Francisco Estuary Institute: Richmond, CA.2013.
Contaminants of Emerging Concern in San Francisco Bay: A Summary of Occurrence Data and Identification of Data Gaps. SFEI Contribution No. 698. p 121.2013.
2010 Annual Monitoring Results. San Francisco Estuary Institute: Richmond, CA.2012.
Perfluoroalkyl compounds (PFCs) in wildlife from an urban estuary. Journal of Environmental Monitoring 14, 146-154.2012.
Pharmaceuticals and Personal Care Products in Wastewater Treatment Plant Influent and Effluent and Surface Waters of Lower South San Francisco Bay. San Francisco Estuary Institute: Oakland, Ca.2009.
San Francisco Bay Triennial Bird Egg Monitoring Program for Contaminants - 2009 Data Summary. U. S. Geological Survey: Davis, CA.2009.
Power Analysis and Optimization of the RMP Status and Trends Program. SFEI Contribution No. 555.2008.
Sources, Pathways and Loadings Workgroup: Five-Year Workplan (2008-12). SFEI Contribution No. 567. San Francisco Estuary Institute: Oakland.2008.
Estuary News RMP Insert 2007. Estuary News.2007.
Synthesis of long-term nickel monitoring in San Francisco Bay. Environmental Research 105, 20-33.2007.
Aqueous Speciation and 1-Octanol-Water Partitioning of Tributyl- and Triphenyltin: Effect of pH and Ion Composition. Environmental Science and Technology 31 (9), 2596-2602.1997.
The Cloudwater Chemistry of Iron and Copper at Great Dun Fell, U.K. Atmospheric Environment 31 (16), 2515-2526.1997.
The Great Dun Fell Cloud Experiment 1993: An Overview. Atmospheric Environment 31 (16), 2393-2405.1997.