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Heberger, M.; Sutton, R.; Buzby, N.; Sun, J.; Lin, D.; Mendez, M.; Hladik, M.; Orlando, J.; Sanders, C.; Furlong, E. 2020. Current-Use Pesticides, Fragrance Ingredients, and Other Emerging Contaminants in San Francisco Bay Margin Sediment and Water. SFEI Contribution No. 934. San Francisco Estuary Institute: Richmond, CA.

The Regional Monitoring Program for Water Quality in San Francisco Bay (RMP) has recently focused attention on better characterization of contaminants in nearshore “margin” areas of San Francisco Bay. The margins of the Lower South Bay are mudflats and shallow regions that receive direct discharges of stormwater and wastewater; as a result, they may have higher levels of urban contaminants than the open Bay. In the summer of 2017, the RMP collected samples of margin
sediment in the South and Lower South Bay for analysis of legacy contaminants. The study described here leveraged that sampling effort by adding monitoring of sediment and water for two additional sets of emerging contaminants: 1) current-use pesticides; and 2) fragrance ingredients including the polycyclic musk galaxolide, as well as a range of other commonly detected emerging contaminants linked to toxicity concerns such as endocrine disruption.

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Miller, E.; Klasios, N.; Lin, D.; Sedlak, M.; Sutton, R.; Rochman, C. 2020. Microparticles, Microplastics, and PAHs in Bivalves in San Francisco Bay. SFEI Contribution No. 976. San Francisco Estuary Institute: Richmond, CA.

California mussels (Mytilus californianus and hybrid Mytilus galloprovincialis / Mytilus trossulus) and Asian clams (Corbicula fluminea) were collected at multiple sites in San Francisco Bay. Mussels from a reference area with minimal urban influence were also deployed in cages for 90 days at multiple sites within the Bay prior to collection.Mussels from the reference time zero site, Bodega Head, had some of the lowest microparticle levels found in this study, along with resident clams from the San Joaquin and Sacramento Rivers and mussels transplanted to Pinole Point. The highest concentrations of microparticles were in mussels transplanted to Redwood Creek and Coyote Creek. The results of this study and current literature indicate that bivalves may not be good status and trends indicators of microplastic concentrations in the Bay unless the interest is in human health exposure via contaminated bivalve consumption.

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Buzby, N.; Lin, D.; Sutton, R. 2020. Neonicotinoids and Their Degradates in San Francisco Bay Water. SFEI Contribution No. 1002. San Francisco Estuary Institute: Richmond, CA.

In the summer of 2017, open Bay water samples were collected during the RMP Status and Trends Water Cruise. Samples were analyzed for 19 neonicotinoids and metabolites. The only neonicotinoid detected was imidacloprid, an active ingredient used in both urban and agricultural applications. Imidacloprid was detected at a single site above the method detection limits (2.2-2.6 ng/L) in Lower South Bay at a level of 4.2 ng/L. This value is within the range of concentrations found in a separate RMP study in water samples collected from the South and Lower South Bay margins in 2017. Imidacloprid was detected at 3 of 12 of the margin sites at levels between 3.9 and 11 ng/L; no other neonicotinoids were detected. Of note, these RMP studies appear to represent the first evaluation of ambient neonicotinoid concentrations in an estuarine environment in the nation.

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Sedlak, M.; Sutton, R.; Miller, L.; Lin, D. 2019. Microplastic Strategy Update. SFEI Contribution No. 951. San Francisco Estuary Institute: Richmond, CA.

Based on the detection of microplastics in San Francisco Bay surface water and Bay Area wastewater effluent in 2015, the Regional Monitoring Program for Water Quality in San Francisco Bay (RMP) convened a Microplastic Workgroup (MPWG) in 2016 to discuss the issue, identify management information needs and management questions (MQs), and prioritize studies to provide information to answer these management questions. The MPWG meets annually to review on-going microplastic projects and to conduct strategic long-term planning in response to new information in this rapidly evolving field.

In this nascent field with new findings published almost daily, the Strategy is designed to be a living document that is updated periodically. This Strategy Update includes a short summary of recent findings from the San Francisco Bay Microplastics Project - a major monitoring effort in the Bay - and an updated multi-year plan based on the newly acquired knowledge and current management needs.

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Gilbreath, A.; McKee, L.; Shimabuku, I.; Lin, D.; Werbowski, L. M.; Zhu, X.; Grbic, J.; Rochman, C. 2019. Multi-year water quality performance and mass accumulation of PCBs, mercury, methylmercury, copper and microplastics in a bioretention rain garden. Journal of Sustainable Water in the Built Environment 5 (4) . SFEI Contribution No. 872.

A multiyear water quality performance study of a bioretention rain garden located along a major urban transit corridor east of San Francisco Bay was conducted to assess the efficacy of bioretention rain gardens to remove pollutants. Based on data collected in three years between 2012 and 2017, polychlorinated biphenyls (PCBs) and suspended sediment concentrations (SSCs) were reduced (>90%), whereas total mercury (Hg), methylmercury (MeHg), and copper (Cu) were moderately captured (37%, 49%, and 68% concentration reduction, respectively). Anthropogenic microparticles including microplastics were retained by the bioretention rain garden, decreasing in concentration from 1.6 particles/L to 0.16 particles/L. Based on subsampling at 50- and 150-mm intervals in soil cores from two areas of the unit, PCBs, Hg, and MeHg were all present at the highest concentrations in the upper 100 mm in the surface media layers. Based on residential screening concentrations, the surface media layer near the inlet would need to be removed and replaced annually, whereas the rest of the unit would need replacement every 8 years. The results of this study support the use of bioretention in the San Francisco Bay Area as one management option for meeting load reductions required by San Francisco Bay total maximum daily loads, and provide useful data for supporting decisions about media replacement and overall maintenance schedules.

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Sutton, R.; Lin, D.; Sedlak, M.; Box, C.; Gilbreath, A.; Holleman, R.; Miller, L.; Wong, A.; Munno, K.; Zhu, X.; et al. 2019. Understanding Microplastic Levels, Pathways, and Transport in the San Francisco Bay Region. SFEI Contribution No. 950. San Francisco Estuary Institute: Richmond, CA.

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:

  1. Contribute to the development and standardization of sample collection and analysis methodology for microplastic transportation research.
  2. 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.
  3. Characterize pathways by which microplastics enter the Bay, including urban stormwater and treated wastewater effluent.
  4. Investigate the contribution of Bay microplastics to the adjacent National Marine Sanctuaries through computer simulations.
  5. Communicate findings to regional stakeholders and the general public through meetings and educational materials.
  6. 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).

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Lin, D.; Sutton, R. 2018. Alternative Flame Retardants in San Francisco Bay: Synthesis and Strategy. SFEI Contribution No. 885. San Francisco Estuary Institute : Richmond, CA.
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Sedlak, M.; Sutton, R.; Wong, A.; Lin, D. 2018. Per and Polyfluoroalkyl Substances (PFAS) in San Francisco Bay: Synthesis and Strategy. SFEI Contribution No. 867. San Francisco Estuary Institute : Richmond, CA.
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Lin, D.; Sutton, R.; Sun, J.; Ross, J. 2018. Screening of Pharmaceuticals in San Francisco Bay Wastewater. SFEI Contribution No. 910. San Francisco Estuary Institute : Richmond, CA.
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Lin, D.; Davis, J. 2018. Support for Sediment Bioaccumulation Evaluation: Toxicity Reference Values for the San Francisco Bay. SFEI Contribution No. 916. San Francisco Estuary Institute : Richmond, CA.
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Lin, D.; Sun, J.; Yee, D.; Franz, A.; Trowbridge, P.; Salop, P. 2017. 2017 RMP Water Cruise Plan. SFEI Contribution No. 845. San Francisco Estuary Institute : Richmond, CA.
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