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Mendez, M.; Kleckner, A.; Sutton, R.; Yee, D.; Wong, A.; Davis, J.; Sigala, M. 2023. 2023 Bay Prey Fish and Near-field / Margins Sediment Sampling and Analysis Plan. SFEI Contribution No. 1141. San Francisco Estuary Institute: Richmond, CA.

This is a sampling and analysis plan for the Bay Status and Trends (S&T) Prey Fish and Near-field / Margins Sediment monitoring for the Regional Monitoring Program for Water Quality in San Francisco Bay (RMP). Bay margins are defined by the RMP as extending from Mean Higher High Water (MHHW) to 1 foot below Mean Lower Low Water (MLLW). These mud flats and adjacent shallow areas of the Bay are productive and highly utilized by biota of interest (humans and wildlife). Near-field stations are located near watershed inputs in the Bay. Prey fish are a key matrix to monitoring the status and impacts of contaminants, especially near margin areas where they have shown strong contamination signals in previous RMP studies. This monitoring design provides a spatially-distributed characterization of contaminant concentrations in fish and sediment found within the margins of Central Bay, South Bay, and Lower South Bay. This study builds on previous S&T efforts to characterize surface sediment contamination across the Bay while piloting routine monitoring of prey fish. Additional samples outside of S&T will be collected for special studies. A subset of samples will be archived for potential future analysis of emerging contaminants or other analyte groups.

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Kleckner, A.; Sutton, R.; Yee, D.; Wong, A.; Davis, J.; Salop, P. 2023. 2023 RMP Dry Season Water Cruise Plan. SFEI Contribution No. 1139. San Francisco Estuary Institute: Richmond, CA.

This report details plans associated with the 2023 Regional Monitoring Program for Water Quality in the San Francisco Estuary (RMP) water cruise. The RMP water sampling program was redesigned in 2002 to adopt a randomized sampling design at thirty-one stations in place of the twenty-six base program stations sampled previously. In 2007, the number of stations was decreased to twenty-two stations, and it remains as such for 2023. The analytes for 2023 are based on the Status and Trends (S&T) Review process that started in 2020.

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Kleckner, A.; Sutton, R.; Yee, D.; Wong, A.; Davis, J.; Salop, P. 2023. 2023 RMP Sediment Cruise Sampling and Analysis Plan. SFEI Contribution No. 1138. San Francisco Estuary Institute: Richmond, CA.

This report details plans associated with the Regional Monitoring Program for Water Quality in the San Francisco Estuary (RMP) deep bay sediment cruise. The RMP, through the Status and Trends monitoring program, conducts routine monitoring of water, sediment and biological tissue. Deep bay stations (water depth lower than 1 foot below MLLW) have been sampled for the Status and Trends sediment program since its inception.  The current monitoring design (reflective of changes made to the Program through the Status and Trends Review process) calls for sampling frequency of deep bay sediment for CECs, PBDEs, and ancillary analytes every five years during the dry season. Every ten years, metals, PAHs, and PCBs will also be sampled. For 2023, sampling operations will entail dry season sample collection at 16 RMP sediment sampling stations for CECs, PBDEs, and ancillary analytes in Central Bay, South Bay, and Lower South Bay.

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Davis, J. 2023. 2023 RMP Update. SFEI Contribution No. 1148. San Francisco Estuary Institute: Richmond, CA.

The overarching goal of the Regional Monitoring Program for Water Quality in San Francisco Bay (RMP) is to answer the highest priority scientific questions faced by managers of Bay water quality. The RMP is an innovative collaboration between the San Francisco Bay Regional Water Quality Control Board, the regulated discharger community, the San Francisco Estuary Institute, and many other scientists and interested parties. The purpose of this document is to provide a concise overview of recent RMP activities and findings, and a look ahead to significant products anticipated in the next two years. The report includes:

  • a brief summary of some of the most noteworthy findings of this multifaceted Program;
  • a description of the management context that guides the Program; and
  • a summary of progress to date and future plans for addressing priority water quality topics.
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Lindborg, A. R.; Overdahl, K. E.; Vogler, B.; Lin, D.; Sutton, R.; P. Ferguson, L. 2023. Assessment of Long-Chain Polyethoxylate Surfactants in Wastewater Effluent, Stormwater Runoff, and Ambient Water of San Francisco Bay, CA. SFEI Contribution No. 1126. American Chemical Society.

Ethoxylated surfactants are ubiquitous organic environmental contaminants that have received continued attention over the past several decades, particularly as manufacturing rates increase worldwide and as toxicity concerns grow regarding alcohol ethoxylates. Presence of these compounds in surface water has been considered primarily the result of contaminated wastewater effluent by ethoxylated surfactant degradates; as a result, monitoring has focused on the small subset of short-chain ethoxylates in wastewater effluent and receiving waters. This study quantified long-chain alcohol and alkylphenol ethoxylated surfactants in San Francisco Bay area stormwater runoff, wastewater effluent, and ambient Bay water to determine concentrations and inform potential pathways of contamination. We employed high-performance liquid chromatography coupled to high-resolution mass spectrometry to quantitate long-chain polyethoxylates, which are rarely monitored in ethoxylated surfactant studies. Similar total ethoxylated surfactant concentrations were observed in stormwater runoff (0.004–4.7 μg/L) and wastewater effluent (0.003–4.8 μg/L, outlier of 45 μg/L). Ambient Bay water contamination (0.0001–0.71 μg/L) was likely the result of both stormwater and wastewater inputs to San Francisco Bay. These results suggest that a broader focus including long-chain compounds and stormwater pathways may be needed to fully characterize the occurrence and impacts of ethoxylated surfactants in urban surface waters.

Plane, E.; Lowe, J.; Miller, G.; Robinson, A.; Crain, C.; Grenier, L. 2023. Baylands Resilience Framework for San Francisco Bay: Wildlife Support. SFEI Contribution No. 1115. San Francisco Estuary Institute: Richmond, CA.
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Méndez, M.; Miller, E.; Lin, D.; Vuckovic, D.; Mitch, W. 2023. Concentrations of Select Commonly Used Organic UV Filters in San Francisco Bay Wastewater Effluent. SFEI Contribution No. 1111. San Francisco Estuary Institute.

Ultraviolet (UV) radiation filters are chemicals designed to absorb or reflect harmful solar radiation, and are used in products as diverse as personal care products (e.g., sunscreens, lotions, and cosmetics) and industrial products (e.g., insecticides, plastics, and paints) to mitigate deleterious effects of sunlight and extend product life. Widespread use of UV filters has led to extensive detections in the environment, and have raised concerns about impacts to aquatic ecosystems. In particular, several organic UV filters that are commonly used in sunscreen have been identified as neurotoxins and endocrine disruptors. To help understand the presence of organic UV filters and their potential to pose risks in San Francisco Bay, three of the most commonly used organic UV filters used in sunscreen (avobenzone, octinoxate, oxybenzone) as well as select metabolites were analyzed in municipal wastewater effluent from the six largest publicly-owned treatment works (POTWs) discharging into the Bay. Note that organic UV filters is a broad chemical class, and other constituents within this class were not included in this study.

Only two of the three organic UV filters analyzed were detected in effluent, avobenzone (detected in 70% of samples) and oxybenzone (83%), with median concentrations of 28 and 86 ng/L, and 90th percentile concentrations of 77 and 209 ng/L, respectively. Concentrations of avobenzone and oxybenzone varied widely across facilities, though there were no clear outlier values. The two POTWs utilizing advanced secondary treatment had the lowest concentrations of any facilities, which may indicate increased removal from these processes. Overall, these concentrations were higher than those reported in one other study of wastewater effluent in the US. An increasing body of literature will help to fully understand the occurrence and fate of organic UV filters in wastewater.

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McKnight, K.; Braud, A.; Dusterhoff, S.; Grenier, L.; Shaw, S.; Lowe, J.; Foley, M.; McKee, L. 2023. Conceptual Understanding of Fine Sediment Transport in San Francisco Bay. SFEI Contribution No. 1114. San Francisco Estuary Institute: Richmond, CA.

Sediment is a lifeblood of San Francisco Bay (Bay). It serves three key
functions: (1) create and maintain tidal marshes and mudflats, (2) transport
nutrients and contaminants, and (3) reduce impacts from excessive human-derived
nutrients in the Bay. Because of these important roles, we need a
detailed understanding of sediment processes in the Bay.

This report offers a conceptual understanding of how fine-grained sediment
(i.e. silt and finer, henceforth called fine sediment) moves around at different
scales within the Bay, now and into the future, to synthesize current knowledge
and identify critical knowledge gaps. This information can be used to support
Bay sediment management efforts and help prioritize funding for research
and monitoring. In particular, this conceptual understanding is designed to
inform future San Francisco Bay Regional Monitoring Program (RMP) work
under the guidance of the Sediment Workgroup of the RMP for Water Quality
in San Francisco Bay, which brings together experts who have worked on
many different components of the landscape, including watersheds and
tributaries, marshes and mudflats, beaches, and the open Bay. This report
describes sediment at two scales: a conceptual understanding of open-Bay
sediment processes at the Bay and subembayment scale (Chapter 2); and
a conceptual understanding of sediment processes at the baylands scale
(Chapter 3). Chapter 4 summarizes the key knowledge gaps and provides
recommendations for future studies.

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San Francisco Estuary Institute. 2023. Ecology for Health: Design Guidance for Fostering Human Health and Biodiversity in Cities. Funded by the Robert Wood Johnson Foundation. SFEI Contribution No. 1130. San Francisco Estuary Institute: Richmond, CA.

Ecology for HealthGreenspaces provide crucial nature contact for urban residents. When we have greater access and exposure to nature in the places where we live, work, learn, and play, we tend to experience better human health outcomes. Urban parks, trees, and vegetation encourage physical activity, reduce anxiety and depression, support social cohesion by providing gathering spaces, and are associated with reduced mortality and improved overall health.

While traditionally biodiversity conservation has focused on large open spaces, cities can also play a key role in supporting biodiversity. Many of the world’s major cities developed in biodiversity hotspots due to historical settlement patterns dependent on natural resources. Thus cities contain vital remnant habitat as well as globally important native and endangered species that rely on urban greenspaces.

As urbanization increases, cities around the world are developing and implementing plans to better integrate nature within urban settings. Many of these plans emphasize the importance of urban greening in providing multiple, substantial benefits such as biodiversity conservation, stormwater management, human health and well-being improvements, climate resilience, and more. However not all greenspaces are created equal in their biodiversity support and human health provision.

The goal of this document is to provide science-based guidance for designing urban spaces that foster both human health and urban biodiversity. Anyone making decisions about land use and urban design in cities across the world can benefit from the recommendations in this document (including community organizations, local non-profits, local leaders and policy makers, city planners, urban designers, landscape architects, engineers, gardeners/horticulturists/arborists, residents, and landowners). However, the majority of the document is specifically aimed at supporting designers and planners who work at the planning, site, and detailed design scales such as landscape architects, civil engineers, and urban designers. As noted in more detail in the limitations section below, this document synthesizes global research and design strategies while strongly informed by our experience as scientists and designers in California’s San Francisco Bay Area.

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Lowe, S.; Huck, K.; Misico, A.; Scirbe, L.; Sussman, D. 2023. Lahontan Surface Water Ambient Monitoring Program’s 20-Year Water Quality Review and Program Recommendations. SFEI Contribution No. 1110. San Francisco Estuary Institute: Richmond. CA. p 137.

This 20-year water quality monitoring status and trends report for the Lahontan Water Board’s Surface Water Ambient Monitoring Program (Regional SWAMP) provides an overview of the environmental settings across the Region to give the reader a sense of the diverse ecological landscape, land uses, distribution and abundance of aquatic resources, and fire history. It includes a retrospective analysis of the Regional SWAMP’s ongoing, targeted water quality monitoring results (2000 - 2021), and concludes by presenting an adaptive monitoring and assessment framework (adapted from the California Wetlands Monitoring Workgroup's Wetland and Riparian Monitoring Plan, known as "WRAMP").  The framework was used to review the program and recommend future monitoring changes to improve efficiencies and address some of the recommendations listed in the Regional SWAMP's 2019 Core Program Review. 

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SFEI. 2023. Landscape Scenario Planning Tool User Guide v2.2.0. San Francisco Estuary Institute: Richmond, Calif.
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Foley, M.; Davis, J.; Yee, D. 2023. Multi-Year Plan 2023. SFEI Contribution No. 1096. San Francisco Estuary Institute: Richmond, California.

The purpose of this document is to guide efforts and summarize plans developed within the RMP. The intended audience includes representatives of the many organizations who directly participate in the Program. This document will also be useful for individuals who are not directly involved with the RMP but are interested in an overview of the Program and where it is heading.  

The organization of this Multi-Year Plan parallels the RMP planning process (Figure 2). Section 1 presents the long-term management plans of the agencies responsible for managing water quality in the Bay and the overarching management questions that guide the Program. The agencies’ long-term management plans provide the foundation for RMP planning (Figure 2). In order to turn the plans into effective actions, the RMP distills prioritized lists of management questions that need to be answered (Page 8). The prioritized management questions then serve as a roadmap for scientists on the Technical Review Committee, workgroups, and strategy teams to plan and implement scientific studies to address the most urgent information needs. This information sharpens the focus on management actions that will most effectively and efficiently improve water quality in the Bay. 

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Bǎlan, S. A.; Andrews, D. Q.; Blum, A.; Diamond, M. L.; Fernández, S. Rojello; Harriman, E.; Lindstrom, A. B.; Reade, A.; Richter, L.; Sutton, R.; et al. 2023. Optimizing Chemicals Management in the United States and Canada through the Essential-Use Approach. Environmental Science & Technology 57 (4).

Chemicals have improved the functionality and convenience of industrial and consumer products, but sometimes at the expense of human or ecological health. Existing regulatory systems have proven to be inadequate for assessing and managing the tens of thousands of chemicals in commerce. A different approach is urgently needed to minimize ongoing production, use, and exposures to hazardous chemicals. The premise of the essential-use approach is that chemicals of concern should be used only in cases in which their function in specific products is necessary for health, safety, or the functioning of society and when feasible alternatives are unavailable. To optimize the essential-use approach for broader implementation in the United States and Canada, we recommend that governments and businesses (1) identify chemicals of concern for essentiality assessments based on a broad range of hazard traits, going beyond toxicity; (2) expedite decision-making by avoiding unnecessary assessments and strategically asking up to three questions to determine whether the use of the chemical in the product is essential; (3) apply the essential-use approach as early as possible in the process of developing and assessing chemicals; and (4) engage diverse experts in identifying chemical uses and functions, assessing alternatives, and making essentiality determinations and share such information broadly. If optimized and expanded into regulatory systems in the United States and Canada, other policymaking bodies, and businesses, the essential-use approach can improve chemicals management and shift the market toward safer chemistries that benefit human and ecological health.

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Sonoma Land Trust and partners. 2023. Petaluma River Baylands Strategy. Prepared by San Francisco Estuary Institute, Sonoma Land Trust, Point Blue Conservation Science, Ducks Unlimited, and Sonoma Resource Conservation District. Funded by the Wildlife Conservation Board.
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Vuckovic, D.; MacDonald, J. A.; Lin, D.; Méndez, M.; Miller, E.; Mitch, W. 2023. Pharmaceuticals, pesticides, and ultraviolet filters in wastewater discharges to San Francisco Bay as drivers of ecotoxicity. Environmental Pollution 336 . SFEI Contribution No. 1153.

Research in the United States evaluating ecotoxic risk to receiving waters posed by contaminants occurring in wastewater discharges typically has focused on measurements of pharmaceuticals and personal care products (PPCPs), with limited evaluations of UV filters and phenylpyrazole and neonicotinoid pesticides. In this study, concentrations of 5 representative pharmaceuticals, 11 pesticides or pesticide degradation products, and 5 ultraviolet filters were measured in 24 h composite samples of six wastewater discharges representing ∼70% of the total wastewater discharged to San Francisco Bay during the summer and fall of 2021. No significant difference was observed between concentrations measured on weekdays vs. weekends. A hydrodynamic model of San Francisco Bay was used to estimate annual average dilution factors associated with different subembayments. With and without considering dilution effects, Risk Quotients were calculated using the 90th percentile of measured concentrations in wastewater effluents and threshold concentrations associated with ecotoxicity. Risk Quotients were highest for the neonicotinoid pesticide, imidacloprid, and exceeded ecotoxicity thresholds in the lower South Bay by a factor of 2.4, even when considering dilution. Compared to commonly measured pharmaceuticals, Risk Quotients for imidacloprid were higher than those for carbamazepine, trimethoprim and diclofenac, and comparable to those for propranolol and metoprolol. Risk Quotients for the pesticide, fipronil, and the UV filter, oxybenzone, were higher than for carbamazepine. The results highlight the need to incorporate pesticides and UV filters with high Risk Quotients into studies in the United States evaluating ecotoxic risk associated with contaminants in municipal wastewater discharges.

Arnold, W. A.; Carigan, C. C.; Cortopassi, G.; Datta, S.; DeWitt, J.; Doherty, A. - C.; Halden, R. U.; Harari, H.; Hartmann, E. M.; Hrubec, T. C.; et al. 2023. Quaternary Ammonium Compounds: A Chemical Class of Emerging Concern. Environmental Science & Technology 57 (20).

Quaternary ammonium compounds (QACs), a large class of chemicals that includes high production volume substances, have been used for decades as antimicrobials, preservatives, and antistatic agents and for other functions in cleaning, disinfecting, personal care products, and durable consumer goods. QAC use has accelerated in response to the COVID-19 pandemic and the banning of 19 antimicrobials from several personal care products by the US Food and Drug Administration in 2016. Studies conducted before and after the onset of the pandemic indicate increased human exposure to QACs. Environmental releases of these chemicals have also increased. Emerging information on adverse environmental and human health impacts of QACs is motivating a reconsideration of the risks and benefits across the life cycle of their production, use, and disposal. This work presents a critical review of the literature and scientific perspective developed by a multidisciplinary, multi-institutional team of authors from academia, governmental, and nonprofit organizations. The review evaluates currently available information on the ecological and human health profile of QACs and identifies multiple areas of potential concern. Adverse ecological effects include acute and chronic toxicity to susceptible aquatic organisms, with concentrations of some QACs approaching levels of concern. Suspected or known adverse health outcomes include dermal and respiratory effects, developmental and reproductive toxicity, disruption of metabolic function such as lipid homeostasis, and impairment of mitochondrial function. QACs’ role in antimicrobial resistance has also been demonstrated. In the US regulatory system, how a QAC is managed depends on how it is used, for example in pesticides or personal care products. This can result in the same QACs receiving different degrees of scrutiny depending on the use and the agency regulating it. Further, the US Environmental Protection Agency’s current method of grouping QACs based on structure, first proposed in 1988, is insufficient to address the wide range of QAC chemistries, potential toxicities, and exposure scenarios. Consequently, exposures to common mixtures of QACs and from multiple sources remain largely unassessed. Some restrictions on the use of QACs have been implemented in the US and elsewhere, primarily focused on personal care products. Assessing the risks posed by QACs is hampered by their vast structural diversity and a lack of quantitative data on exposure and toxicity for the majority of these compounds. This review identifies important data gaps and provides research and policy recommendations for preserving the utility of QAC chemistries while also seeking to limit adverse environmental and human health effects.

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Yee, D.; Wong, A. 2023. Re-evaluation of the Floating Percentile Method for Deriving Dredged Sediment Screening Guidelines. SFEI Contribution No. 1143. San Francisco Estuary Institute: Richmond, California.

This document summarizes a study conducted for the Regional Monitoring Program for Water Quality in San Francisco Bay (RMP) to re-evaluate the use of the Floating Percentile Method
(FPM) to derive sediment screening guidelines for dredged material reuse in the San Francisco Bay Region. The Long Term Management Strategy (LTMS) has a goal to use at least 40% of the sediment dredged from San Francisco Bay for beneficial reuse (USACE, 1998). The suitability of dredged sediment for beneficial reuse is in part determined by concentrations of toxic pollutants.The San Francisco Regional Water Quality Control Board (SFB-RWQCB) issued draft screening criteria in 2000 to categorize the suitability of sediment for reuse as either “surface” sediment, that may be placed near the surface for re-use in wetlands, or “foundation” sediment, that is buried under sediment that meets surface criteria. Contaminant concentration guidelines for surface sediment are lower than foundation sediment, based on the assumption that biota are more likely to be exposed to surface sediment than deeper foundation sediment.

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Dusterhoff, S.; Whipple, A.; Baumgarten, S.; Robinson, A.; Shaw, S.; Stark, K.; Askevold, R. 2023. Restoration Plan for the Laguna de Santa Rosa. SFEI Contribution No. 1123. San Francisco Estuary Institute: Richmond, CA.

The Laguna de Santa Rosa is an expansive freshwater wetland complex that hosts a rich diversity of plant and wildlife species, and is also home to a thriving agricultural community. Since the mid-19th century, modifications to the Laguna and its surrounding landscape have degraded habitat conditions for both wildlife and people. Together with partners at the Laguna de Santa Rosa Foundation, and funded by Sonoma Water and the California Department of Fish and Wildlife, the goal of the Laguna de Santa Rosa Master Restoration Plan project is to develop a plan that supports ecosystem services in the Laguna—through the restoration and enhancement of landscape processes that form and sustain habitats and improve water quality—while considering flood management issues and the productivity of agricultural lands. 

The first phase of the project was the creation of the Restoration Vision for the Laguna de Santa Rosa. The report details a long-term vision for the landscape which highlights opportunities for multi-benefit habitat restoration and land management within the Laguna’s 100-year floodplain. It presents an understanding of the landscape functioning from past, present, and potential future perspectives. Starting with a picture of the historical ecology of the Laguna that details the magnitude of change in habitat conditions over the past two centuries, the document then presents an understanding of key physical processes that affect today’s Laguna. The restoration concepts described in the Vision represent a potential future Laguna, and were developed and vetted through a series of workshops in which technical advisers, management advisers, tribal representatives, and local landowners and stakeholders shared their expertise and helped shape the concepts. 

The second phase of this project was the development of a Restoration Plan for the Laguna de Santa Rosa that was built from the Vision. The Restoration Plan was developed through a collaborative process that focused on moving forward identified restoration opportunities into conceptual designs that can be used to establish implementable restoration projects. The Restoration Plan includes the following elements:

  • A restoration framework that offers a planning structure for landscape scale restoration that can be further developed and refined over time.
  • Restoration project concepts in the Laguna’s 100-year floodplain developed from selected restoration opportunity areas shown in the Vision.
  • Criteria for prioritizing and sequencing restoration project concepts.

The utilization of the Restoration Plan and the ultimate success of restoration efforts in the Laguna will require local landowner support and adequate funding to implement the restoration and manage and sustain the benefits through long-term stewardship. It will also require coordination among all the agencies responsible for managing the land and water within the Laguna and its surrounding watershed. With commitment and collaboration the Laguna


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McKee, L.; Peterson, D.; Braud, A.; Foley, M.; Dusterhoff, S.; Lowe, J.; King, A.; Davis, J. 2023. San Francisco Bay Sediment Modeling and Monitoring Workplan. SFEI Contribution No. 1100. San Francisco Estuary Institute: Richmond, CA.

This document was prepared with guidance gained through two RMP Sediment Workgroup workshops held in late 2022 and early 2023. Given the variety of participants involved, this Workplan encompasses interests beyond San Francisco Bay RMP funders. We thank the attendees for their contributions. 

In 2020, the Sediment Workgroup (SedWG) of the Regional Monitoring Program for Water Quality in San Francisco Bay (RMP) completed a Sediment Monitoring and Modeling Strategy (SMMS) which laid out a conceptual level series of data and information gaps and generally recommended the use of both empirical data collection and modeling tools to answer initial high priority management questions (McKee et al., 2020). At the time, the SMMS promoted the use of surrogates such as time-continuous turbidity measurements for cross-section flux modeling within the Bay without an understanding of existing Bay hydrodynamic models, their strengths, weaknesses, and potential uses for understanding coupled Bay-mudflat-marsh processes. Since then, the Wetland Regional Monitoring Program (WRMP, www.wrmp.org) has generally promoted the use of coupling monitoring and modeling techniques to inform wetlands sediment management decisions. In addition, he completion of the Sediment for Survival report (a RMPEPA funded collaboration) and the further development of sediment conceptual models has also advanced the need for a coupled dynamic modeling and monitoring program that has the capacity to explore more complex management questions (Dusterhoff et al., 2021; SFEI, 2023). Such a program will take time to develop, but will be more cost-efficient and adaptable and allow for more timely answers to pressing questions. 

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Zi, T. 2023. Stevens Creek Reservoir – Forecast Informed Reservoir Operation (FIRO) Phase One Report. Peterson, D., Stark, K., Eds.. SFEI Contribution No. 1120. Prepared for SCV Water District.
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Gilbreath, A. N.; Stark, K.; Pearce, S.; Mckee, L. 2023. Suspended Sediment Loads Analysis of Four Creeks in the San Francisco Bay Area. SFEI Contribution No. 1134. San Francisco Estuary Institute: Richmond, CA.
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H. T. Harvey & Associates. 2023. Sycamore Alluvial Woodland Pilot Study Implementation Guidelines. Prepared for Zone 7 Water Agency and US Environmental Protection Agency’s Water Quality Improvement Fund. In collaboration with San Francisco Estuary Institute.

This document supports planting-based approaches for sycamore enhancement by providing site-level revegetation techniques for installing, maintaining and monitoring sycamore plantings.

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Pearce, S.; Whipple, A.; Harris, K.; Lee, V.; Hegstad, R.; McClain, C. 2023. Sycamore Alluvial Woodland Restoration and Enhancement Suitability Study. In collaboration with Alameda County Flood Control and Water Conservation District, Zone 7. Prepared for the US Environmental Protection Agency’s Water Quality Improvement Fund. SFEI Contribution No. 1128. San Francisco Estuary Institute: Richmond, CA.

The “Sycamore Alluvial Woodland Restoration and Enhancement Suitability Study” addresses distribution and regeneration patterns and restoration strategies of sycamore alluvial woodland (SAW) habitat, a unique and relatively rare native vegetation community adapted to California’s intermittent rivers and streams. The report was produced by SFEI and H. T. Harvey & Associates, as part of the US EPA Water Quality Improvement Fund Preparing for the Storm grant, led by Zone 7 Water Agency.

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Moran, K.; Sutton, R. 2023. Tire Wear: Emissions Estimates and Market Insights to Inform Monitoring Design. Gilbreath, A., Méndez, M., Lin, D., Eds.. SFEI Contribution No. 1109. San Francisco Estuary Institute: Richmond, CA.

Every vehicle on the road sheds tiny particles from its rubber tires into the environment. Tire wear is one of the top sources of microplastic releases to the environment. Tire wear also disperses tire-related chemicals into the environment. SFEI studies supported by the Regional Monitoring Program for Water Quality in San Francisco Bay (RMP) and others have found tire wear particles and tire-related chemicals in San Francisco Bay and its small tributaries, which drain the Bay watershed’s local urban areas. The RMP has developed a short-term multi-year plan of potential special studies (“Tires Strategy”) that responds to recent data revealing the magnitude of tire particle and chemical emissions and their potential toxicity to aquatic organisms.

This article is available upon request. Please message [email protected] for the materials.

Pearce, S. A.; Stark, K. 2023. Translating Sediment Science Into Action: Documenting Beneficial Sediment Reuse. SFEI Contribution No. 1124. San Francisco Estuary Institute: Richmond, CA.

The Preparing for the Storm project, led by Zone 7 Water Agency (Zone 7) and funded by the US Environmental Protection Agency (EPA) Water Quality Improvement Fund, aims to develop science-based plans, strengthen existing and new partnerships, and pilot new methodologies for tackling these issues surrounding coarse sediment. As a task within this larger project, this report describes four projects in the East Bay that serve as case studies for beneficial reuse of sediment. Each example highlights a project with sediment that could be reused (in lieu of landfilling) or a project that needs additional sediment and could benefit from deliveries of sediment that normally would not have been beneficially reused.

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Lin, D.; Hamilton, C.; Hobbs, J.; Miller, E.; Sutton, R. 2023. Triclosan and Methyl Triclosan in Prey Fish in a Wastewater-influenced Estuary. Environmental Toxicology and Chemistry . SFEI Contribution No. 1112.

While the antimicrobial ingredient triclosan has been widely monitored in the environment, much less is known about the occurrence and toxicity of its major transformation product, methyl triclosan. An improved method was developed and validated to effectively extract and quantify both contaminants in fish tissue and was used to characterize concentrations in small prey fish in areas of San Francisco Bay where exposure to triclosan via municipal wastewater discharges was expected to be highest. Concentrations of triclosan (0.44–57 ng/g ww, median 1.9 ng/g ww) and methyl triclosan (1.1–200 ng/g ww, median 36 ng/g ww) in fish tissue decreased linearly with concentrations of nitrate in site water, used as indicators of wastewater influence. The total concentrations of triclosan and methyl triclosan measured in prey fish were below available toxicity thresholds for triclosan, but there are few ecotoxicological studies to evaluate impacts of methyl triclosan. Methyl triclosan represented up to 96% of the total concentrations observed. These results emphasize the importance of monitoring contaminant transformation products, which can be present at higher levels than the parent compound.

Kleckner, A.; Sutton, R.; Yee, D.; Gilbreath, A.; Trinh, M. 2023. Water Year 2023 RMP Near-Field Water Sampling and Analysis Plan. SFEI Contribution No. 1142. San Francisco Estuary Institute: Richmond, CA.

This report details plans associated with the pilot near-field water sampling for the Regional Monitoring Program for Water Quality in San Francisco Bay (RMP). The RMP recently reviewed the Status & Trends (S&T) Program and added a pilot effort to quantify contaminants of emerging concern (CECs) in Bay water in areas near (“near-field” of) expected loading pathways during or shortly after storm events and during the dry season. For the first year of the pilot (Water Year 2022), the near-field design included three targeted, near-field stations and four ambient Bay stations. Subsequent years added a fourth near-field station. Samples will be collected at these stations during or shortly after two storm events, and once in the dry season. The analytes that are being measured include bisphenols, organophosphate esters (OPEs), PFAS, and a suite of stormwater CECs.

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Grosso, C.; Lowe, S.; Pearce, S.; O'Connor, K.; Teunis, L.; Stein, E. D.; Siu, J.; Scianni, M. 2023. WRAMP Training and Outreach Plan. SFEI Contribution No. 1136. p 39.

The goal of this Training and Outreach Plan is to increase the overall awareness and use  of the WRAMP datasets and tools in support of wetland resource planning,  management, and project performance tracking in California. Specifically, a near-term  goal is to develop modular training sessions that can be linked together in different  ways to customize how the datasets, monitoring methods, and online tools might be  used for different purposes. 

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Applied Marine Sciences. 2022. 2021 RMP Water Cruise Report. SFEI Contribution No. 1098. Applied Marine Sciences: Livermore, CA.

This report details activities associated with the biannual Regional Monitoring Program for Water Quality in the San Francisco Estuary (RMP) water cruise. The RMP water sampling program was redesigned in 2002 to adopt a randomized sampling design at thirty-one sites in place of the twenty-six “spine of the Estuary” stations sampled previously. In 2007, the number of sites was decreased to twenty-two stations, combined probabilistic and historic, and it remains as such for 2021. 

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Davis, J.; Foley, M.; Askevold, R. A.; Sutton, R.; Senn, D.; Plane, E. 2022. 2022 Pulse of the Bay. SFEI Contribution No. 1095. San Francisco Estuary Institute: Richmond, California.

The theme of the 2022 Pulse is "50 Years After the Clean Water Act." Nine different individuals or groups have contributed perspectives on progress to date and challenges ahead. This Pulse also includes summaries, from a historical perspective, on the major water quality parameters of concern in the Bay.   

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Foley, M. M. 2022. 2022 RMP Multi-Year Plan. SFEI Contribution No. 1058. San Francisco Estuary Institute: Richmond, California.
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Foley, M. 2022. 2023 Detailed Workplan and Budget. SFEI Contribution No. 1117. San Francisco Estuary Institute: Richmond, California.
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Plane, E.; Lowe, J. 2022. Adaptation Pathways: San Leandro Operational Landscape Unit. SFEI Contribution No. 1077. San Francisco Estuary Institute: Richmond, CA.
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McKnight, K.; Plane, E. 2022. Adaptation Planning for the Bay Point Operational Landscape Unit. SFEI Contribution No. 1078. San Francisco Estuary Institute: Richmond, CA.
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Morris, J.; Drexler, J. Z.; Vaughn, L. Smith; Robinson, A. 2022. An assessment of future tidal marsh resilience in the San Francisco Estuary through modeling and quantifiable metrics of sustainability. Frontiers in Environmental Science 10.

Quantitative, broadly applicable metrics of resilience are needed to effectively manage tidal marshes into the future. Here we quantified three metrics of temporal marsh resilience: time to marsh drowning, time to marsh tipping point, and the probability of a regime shift, defined as the conditional probability of a transition to an alternative super-optimal, suboptimal, or drowned state. We used organic matter content (loss on ignition, LOI) and peat age combined with the Coastal Wetland Equilibrium Model (CWEM) to track wetland development and resilience under different sea-level rise scenarios in the Sacramento-San Joaquin Delta (Delta) of California. A 100-year hindcast of the model showed excellent agreement (R2 = 0.96) between observed (2.86 mm/year) and predicted vertical accretion rates (2.98 mm/year) and correctly predicted a recovery in LOI (R2 = 0.76) after the California Gold Rush. Vertical accretion in the tidal freshwater marshes of the Delta is dominated by organic production. The large elevation range of the vegetation combined with high relative marsh elevation provides Delta marshes with resilience and elevation capital sufficiently great to tolerate centenary sea-level rise (CLSR) as high as 200 cm. The initial relative elevation of a marsh was a strong determinant of marsh survival time and tipping point. For a Delta marsh of average elevation, the tipping point at which vertical accretion no longer keeps up with the rate of sea-level rise is 50 years or more. Simulated, triennial additions of 6 mm of sediment via episodic atmospheric rivers increased the proportion of marshes surviving from 51% to 72% and decreased the proportion drowning from 49% to 28%. Our temporal metrics provide critical time frames for adaptively managing marshes, restoring marshes with the best chance of survival, and seizing opportunities for establishing migration corridors, which are all essential for safeguarding future habitats for sensitive species.

Mendez, M.; Miller, E.; Liu, J.; Chen, D.; Sutton, R. 2022. Bisphenols in San Francisco Bay: Wastewater, Stormwater, and Margin Sediment Monitoring. SFEI Contribution No. 1093. San Francisco Estuary Institute: Richmond, CA.

Bisphenols are a class of synthetic, mobile, endocrine-disrupting chemicals. Bisphenol A (BPA), the most well-studied bisphenol, is produced and used in vast quantities worldwide—especially in polycarbonate plastics and as a polymer additive. Recently, some manufacturers have begun using alternative bisphenol compounds, such as bisphenol F (BPF) and bisphenol S (BPS). These uses of bisphenols have led to widespread bisphenol detections in the environment and wildlife. The present study examined wastewater effluent in the San Francisco Bay Area and San Francisco Bay sediment samples for 17 bisphenols. The effluent samples were compared to available stormwater runoff data to better understand bisphenol transport, fate, and potential risks to wildlife.

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Lowe, S.; Pearce, S. 2022. Building Capacity of the California Wetland Program Plan to Protect and Restore Vernal Pools. SFEI Contribution No. 1087. San Francisco Estuary Institute: Richmond. CA. p 30.

This report describes the updates to the vernal pool habitat map, the development of the ambient baseline ecological condition survey of vernal pool systems within the Central Valley, and the development and results of the habitat development curve. A fictional project example shows how CRAM and the vernal pool complex CDFs and HDCs can help project proponents and the regulatory agencies think critically about project designs (using CRAM Attributes and Metrics as a standard measure), evaluate project conditions within a regional landscape context, and monitor project performance over time to ensure that project goals are met.

Funding for this report was provided through an agreement with the U.S. Environmental Protection Agency (USEPA).  This report does not necessarily reflect the views and policies of USEPA nor does the mention of trade names or commercial products within this report constitute endorsement or recommendation for use.

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Sutton, R.; Lin, D. 2022. CECs in California’s Ambient Aquatic Ecosystems: Occurrence and Risk Screening of Key Classes. Miller, E., Wong, A., Mendez, M., Eds.. ASC Contribution. SFEI Contribution No. 1066. Aquatic Science Center: Richmond, CA.
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Baumgarten, S. A. 2022. Ecological Horticulture at the Presidio. Lee, V., Bazo, M., Spotswood, E., Eds.. SFEI Contribution No. 1080. San Francisco Estuary Institute: Richmond, Ca.

The Presidio of San Francisco—the nation’s largest urban national park—is located in an area of exceptional ecological diversity. Historically, many different habitat types thrived in the mix of windswept dunes, riparian forests, and curious dwarf oak woodlands that characterized this landscape. Many of these habitat types are rare today (and some were even rare in the region historically), and together they harbor a host of unique plants and animals.

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Whipple, A.; Robinson, A.; Safran, S. M. 2022. ELEVATION AND OPPORTUNITY IN THE DELTA: Restoring the right thing in the right place. SFEI Contribution No. 1082. San Francisco Estuary Institute: Richmond, Ca.


A future Sacramento-San Joaquin Delta and Suisun Marsh (“Delta” herein) that supports healthy ecosystems and native species, while also meeting flood risk reduction, water supply, water quality, carbon sequestration, economic, and cultural objectives, requires that appropriate restoration and management actions be taken in the right place at the right time. Geographic setting affects the potential opportunities available—not all actions are suitable everywhere. Physical factors determining what types of activities are appropriate now and in the future include a site’s elevation, degree of tidal and fluvial influence, salinity, soil type, and local effects of climate change, which all vary spatially across the Delta. While there has been considerable progress over the last several decades, continued acceleration of the pace and scale of enhancement actions appropriate to landscape position is needed. Understanding the physical template is necessary for developing strategies that move beyond opportunistic restoration, support resilience over time, and have the potential to connect and magnify benefits across the larger landscape.

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Vaughn, L. Smith; Plane, E.; Harris, K.; Robinson, A.; Grenier, L. 2022. Leveraging Wetlands for a Better Climate Future: Incorporating Blue Carbon into California's Climate Planning. SFEI Contribution No. 1084. San Francisco Estuary Institute: Richmond, CA. p 31.

The 2022 update to California’s climate change Scoping Plan incorporates management actions in the state’s forests, shrublands/chaparral, grasslands, croplands, developed lands, deltaic wetlands, and sparsely vegetated lands. Missing from this list are the tidally-influenced coastal ecosystems outside the Sacramento-San Joaquin Delta. These blue carbon ecosystems support high rates of carbon storage and sequestration while providing many co-benefits that can enhance coastal climate change resilience. With sufficient data and robust modeling approaches, California has the opportunity to incorporate blue carbon in future Scoping Plan updates and set actionable targets for restoration, migration space conservation, and other management activities that promote long-term survival of the state’s coastal wetlands. To support this goal, this report offers a high-level overview of the state of the science for blue carbon quantification in California. This summary, which covers datasets and quantification approaches, key focus areas for additional science investment, and example scenarios for coastal wetland restoration, is intended to facilitate broader inclusion of blue carbon in future Scoping Plan updates and other state-level climate-planning documents.

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Hampton, L. M. Thornto; De Frond, H.; Hermabessiere, L.; Miller, E.; de Ruijter, V. N.; Faltynkova, A.; Kotar, S.; Monclús, L.; Siddiqui, S.; Völker, J.; et al. 2022. A living tool for the continued exploration of microplastic toxicity. Microplastics and Nanoplastics 2 (13).

Throughout the past decade, many studies have reported adverse effects in biota following microplastic exposure. Yet, the field is still emerging as the current understanding of microplastic toxicity is limited. At the same time, recent legislative mandates have required environmental regulators to devise strategies to mitigate microplastic pollution and develop health-based thresholds for the protection of human and ecosystem health. The current publication rate also presents a unique challenge as scientists, environmental managers, and other communities may find it difficult to keep up with microplastic research as it rapidly evolves. At present, there is no tool that compiles and synthesizes the data from these studies to allow for visualization, interpretation, or analysis. Here, we present the Toxicity of Microplastics Explorer (ToMEx), an open access database and open source accompanying R Shiny web application that enables users to upload, search, visualize, and analyze microplastic toxicity data. Though ToMEx was originally created to facilitate the development of health-based thresholds to support California legislations, maintaining the database by the greater scientific community will be invaluable to furthering research and informing policies globally. The database and web applications may be accessed at https://microplastics.sccwrp.org/.

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Moran, K.; Askevold, R. 2022. Microplastics from Tire Particles in San Francisco Bay Factsheet. SFEI Contribution No. 1074. San Francisco Estuary Institute: Richmond, CA.

As we drive our cars, our tires shed tiny particles

When it rains, stormwater runoff carries tire particles—and the toxic chemicals they contain—from city streets and highways to storm drains and fish habitat in creeks and estuaries like San Francisco Bay. Stormwater washes trillions of tire particles into the Bay each year.

How do tires affect wildlife?

A recent study found a highly toxic chemical (“6PPD-quinone”) derived from vehicle tires in Bay Area stormwater at levels that are lethal to coho salmon. New data indicate that steelhead, a salmon species still migrating through the Bay to surrounding watersheds, are also sensitive to this chemical.

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Shimabuku, I.; Chen, D.; Wu, Y.; Miller, E.; Sun, J.; Sutton, R. 2022. Occurrence and risk assessment of organophosphate esters and bisphenols in San Francisco Bay, California, USA. Science of the Total Environment 813 . SFEI Contribution No. 982.

Organophosphate esters (OPEs) and bisphenols are two classes of industrial chemicals that are ubiquitously detected in environmental matrices due to high global production and widespread use, particularly in the manufacture of plastic products. In 2017, water samples collected throughout the highly urbanized San Francisco Bay were analyzed for 22 OPEs and 16 bisphenols using liquid chromatography-electrospray ionization-Q Trap-mass spectrometry. Fifteen of the 22 OPEs were detected, with highest median concentrations in the order TCPP (42 ng/L) > TPhP (9.5 ng/L) > TBOEP (7.6 ng/L) > TnBP (7.5 ng/L) > TEP (6.7 ng/L) > TDCIPP (6.2 ng/L). In contrast, only two of 16 bisphenols, BPA and BPS, were quantified, with concentrations ranging from <0.7–35 ng/L and <1–120 ng/L, respectively. BPA and a few OPEs (EHDPP and TEHP) were primarily present in the particulate phase, while BPS and all other observed OPEs were predominantly found in the dissolved phase. Pairwise correlation analysis revealed several strong, positive correlations among OPEs, and few weak, negative correlations between OPEs and BPA, suggesting differences between the two classes with respect to their sources, pathways, and/or fate in the environment. Concentrations of OPEs and bisphenols observed in this study were generally consistent with reported concentrations in other estuarine and marine settings globally. TDCIPP exceeded existing predicted no-effect concentrations (PNECs) at some sites, and six other compounds (TCrP, IDDPP, EHDPP, TPhP, TBOEP, and BPA) were observed at levels approaching individual compound PNECs (not considering mixture effects), indicating potential risks to Bay biota. These results emphasize the need to control releases of these contaminants in order to protect the ecosystem. Periodic monitoring can be used to maintain vigilance in the face of potential regrettable substitutions.

Mendez, M.; Trinh, M.; Miller, E.; Lin, D.; Sutton, R. 2022. PFAS in San Francisco Bay Water. SFEI Contribution No. 1094. San Francisco Estuary Institute: Richmond, CA.

Per- and polyfluoroalkyl substances (PFAS), a family of thousands of synthetic, fluorine-rich compounds commonly referred to as “forever chemicals,” are known for their thermal stability, non-reactivity, and surfactant properties. These unique compounds have widespread uses across consumer, commercial, and industrial products, resulting in widespread occurrence in the environment and wildlife across the globe. This study analyzed ambient surface water in San Francisco Bay for 40 PFAS to discern the occurrence, fate, and potential risks to ecological and human health.

Eleven of 40 PFAS were detected in ambient surface water collected in 2021 from 22 sites in the Bay. Seven PFAS (PFPeA, PFHxA, PFHpA, PFOA, PFBS, PFHxS, and PFOS), were found in at least 50% of samples. PFHxA and PFOA were the most frequently detected analytes (detection frequencies of 86% and 77%, respectively). PFPeA and PFHxA were generally found at the highest concentrations across sites, with median and maximum concentrations of 1.6 and 4.8 ng/L and 1.5 and 5.7 ng/L, respectively. Pairwise Spearman's correlations revealed strong positive correlations  (p <0.001; r > 0.77) among the seven PFAS detected in at least 50% of sites, suggesting significant similarities between their sources, pathways, and/or fate in the environment. PFBA, PFNA, PFDA, and 6:2 FTS were found at a limited number of sites in the Bay. 6:2 FTS was found at a single site at 14 ng/L, the highest concentration of any individual PFAS in the Bay. The sums of detected PFAS for all sites had median and maximum concentrations of 10 and 29 ng/L, respectively.

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Hampton, L. M. Thornto; Bouwmeester, H.; Brander, S. M.; Coffin, S.; Cole, M.; Hermabessiere, L.; Mehinto, A. C.; Miller, E.; Rochman, C. M.; Weisberg, S. B. 2022. Research recommendations to better understand the potential health impacts of microplastics to humans and aquatic ecosystems. Microplastics and Nanoplastics 2 (18).

To assess the potential risk of microplastic exposure to humans and aquatic ecosystems, reliable toxicity data is needed. This includes a more complete foundational understanding of microplastic toxicity and better characterization of the hazards they may present. To expand this understanding, an international group of experts was convened in 2020–2021 to identify critical thresholds at which microplastics found in drinking and ambient waters present a health risk to humans and aquatic organisms. However, their findings were limited by notable data gaps in the literature. Here, we identify those shortcomings and describe four categories of research recommendations needed to address them: 1) adequate particle characterization and selection for toxicity testing; 2) appropriate experimental study designs that allow for the derivation of dose-response curves; 3) establishment of adverse outcome pathways for microplastics; and 4) a clearer understanding of microplastic exposure, particularly for human health. By addressing these four data gaps, researchers will gain a better understanding of the key drivers of microplastic toxicity and the concentrations at which adverse effects may occur, allowing a better understanding of the potential risk that microplastics exposure might pose to human and aquatic ecosystems.

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Whipple, A.; Grenier, L.; Safran, S. M.; Zeleke, D.; Wells, E.; Deverel, S.; Olds, M.; Cole, S.; Rodríguez-Flores, J.; Guzman, A.; et al. 2022. RESILIENT STATEN ISLAND: Landscape Scenario Analysis Pilot Application. SFEI Contribution No. 1083. San Francisco Estuary Institute: Richmond, Ca.

A central motivating question for the Sacramento-San Joaquin Delta science and management community is what should be done, where and when, to support future Delta landscapes that are ecologically and economically viable and resilient to change. Actions must be taken that have the greatest potential for achieving multiple benefits. This is especially important given the urgency to rapidly transition Delta landscapes to address biodiversity loss, erosion of ecosystem resilience, flood risk, water supply reliability, and cultural and economic sustainability. Landscape-scale planning is needed to examine how individual actions add up to meaningful change. Such planning involves figuring out how different areas can provide different functions at different times and helps show how choices made now can help shift trajectories toward desired outcomes. Too often, land use and management decisions are made based on a limited set of objectives or at the site scale, resulting in missed opportunities. Actions (or inaction) should not foreclose on critical opportunities. Moving forward, there is great need to more effectively compare possible future scenarios across a range of ecological and economic factors. This scenario analysis for Staten Island — a large Delta island managed for multiple uses and facing challenges similar to elsewhere in the Delta — provides an approach to help address this need.

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Mehinto, A. C.; Wagner, M.; Hampton, L. M. Thornto; Burton, Jr, A. G.; Miller, E.; Gouin, T.; Weisberg, S. B.; Rochman, C. M. 2022. Risk-based management framework for microplastics in aquatic ecosystems. Microplastics and Nanoplastics 2 (17).

Microplastic particles (MPs) are ubiquitous across a wide range of aquatic habitats but determining an appropriate level of risk management is hindered by a poor understanding of environmental risk. Here, we introduce a risk management framework for aquatic ecosystems that identifies four critical management thresholds, ranging from low regulatory concern to the highest level of concern where pollution control measures could be introduced to mitigate environmental emissions. The four thresholds were derived using a species sensitivity distribution (SSD) approach and the best available data from the peer-reviewed literature. This included a total of 290 data points extracted from 21 peer-reviewed microplastic toxicity studies meeting a minimal set of pre-defined quality criteria. The meta-analysis resulted in the development of critical thresholds for two effects mechanisms: food dilution with thresholds ranging from ~ 0.5 to 35 particles/L, and tissue translocation with thresholds ranging from ~ 60 to 4100 particles/L. This project was completed within an expert working group, which assigned high confidence to the management framework and associated analytical approach for developing thresholds, and very low to high confidence in the numerical thresholds. Consequently, several research recommendations are presented, which would strengthen confidence in quantifying threshold values for use in risk assessment and management. These recommendations include a need for high quality toxicity tests, and for an improved understanding of the mechanisms of action to better establish links to ecologically relevant adverse effects.

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Zi, T.; Braud, A.; McKee, L. J.; Foley, M. 2022. San Francisco Bay Watershed Dynamic Model (WDM) Progress Report, Phase 2. SFEI Contribution No. 1091. San Francisco Estuary Institute: Richmond, California.

The San Francisco Bay total maximum daily loads (TMDLs) call for a 50% reduction in mercury (Hg) loads by 2028 and a 90% reduction in PCBs loads by 2030. In support of these TMDLs, the Municipal Regional Permit for Stormwater (MRP) (SFBRWQCB, 2009, SFBRWQCB, 2015, SFBRWQCB, 2022) called for the implementation of control measures to reduce PCBs and Hg loads from urbanized tributaries. In addition, the MRP has identified additional information needs associated with improving understanding of sources, pathways, loads, trends, and management opportunities of pollutants of concern (POCs). In response to the MRP requirements and information needs, the Small Tributary Loading Strategy (STLS) was developed, which outlined a set of management questions (MQs) that have been used as the
guiding principles for the region’s stormwater-related activities. In recognition of the need to evaluate changes in loads or concentrations of POCs from small tributaries on a decadal scale, the updated 2018 STLS Trends Strategy (Wu et al., 2018) prioritized the development of a new dynamic regional watershed model for POCs (PCBs and Hg focused) loads and trends. This regional modeling effort will provide updated estimates of POC concentrations and loads for all local watersheds that drain to the Bay. The Watershed Dynamic Model (WDM) will also provide
a mechanism for evaluating the impact of management actions on future trends of POC loads or concentrations.

As a multi-use modeling platform, the WDM is being developed to include other pollutants, such as contaminants of emerging concern (CECs), sediment, and nutrients and to be coupled with a Bay fate model to form an integrated watershed-Bay modeling framework to address Regional Monitoring Program (RMP) management questions. As this model is developed, flexibility to link with other models will be an important consideration.

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May, C. L.; Mohan, A.; Plane, E.; Ramirez-Lopez, D.; Mak, M.; Luchinsky, L.; Hale, T.; Hill, K. 2022. Shallow Groundwater Response to Sea-Level Rise: Alameda, Marin, San Francisco, and San Mateo Counties. Pathways Climate Institute and San Francisco Estuary Institute.

The response of shallow groundwater to sea-level rise is a relatively new field of study. For low-lying coastal communities, sea-level rise adaptation efforts must consider the potential for groundwater rise to avoid maladaptation. The need to better understand this slow and chronic threat was identified as a critical data gap in the San Francisco Bay Area’s (Bay Area’s) adaptation efforts during the Bay Area Groundwater and Sea-Level Rise Workshop in 2019.

Pathways Climate Institute LLC (Pathways) and the San Francisco Estuary Institute (SFEI) gathered and analyzed multiple data sets and collaborated with city and county partners to analyze and map the existing “highest annual” shallow groundwater table and its likely response to future sea-level rise. This effort covers four counties (Alameda, Marin, San Francisco, San Mateo) and was funded by the Bay Area Council’s California Resilience Challenge. The study focused on the San Francisco Bay side of each county and does not include the Pacific coastline of Marin, San Francisco, nor San Mateo Counties. An advisory committee composed of city and county representatives provided essential support by gathering data and reviewing depth-to-groundwater maps. Additional academic and agency advisors participated in project team meetings and informed project direction. This effort produced the following publicly available data and online tools to support adaptation efforts:

  • Existing and future condition depth to groundwater GIS data available for download (geodatabase format).
  • A StoryMap providing background information and graphical representations of the processes and impacts of groundwater rise.
  • Web maps showing: (1) existing depth to groundwater; and (2) a comparison of the extent of emergent groundwater to the extent of coastal flooding under various sea-level-rise scenarios.
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Mckee, L.; Gilbreath, A.; Sabin, L. 2022. Small Tributaries Pollutants of Concern Reconnaissance Monitoring: Application of Storm-event Loads and Yields-Based and Congener-Based PCB Site Prioritization Methodologies. SFEI Contribution No. 1067.

Stormwater agencies in the San Francisco Bay Area are identifying watershed areas that are polluted with PCBs in order to prioritize management efforts to reduce impairment in the Bay caused by PCBs carried in stormwater. Water sampling during storms has been used to characterize PCB concentrations but management prioritization based on the comparison of concentrations between watersheds is made difficult due to variations in flow and sediment erosion between storms and in relation to varying land use. In addition, identifying PCB source areas within priority watersheds has proven complex and costly. To address these challenges, the San Francisco Bay Regional Monitoring Program (RMP) has developed two new interpretive methods based on storm-event PCB yields (PCBs mass per unit area per unit time) and fingerprints of Aroclors (commercial PCB mixtures) that make existing data more useful for decision-making. 

The objectives of this study were to: 

  • Apply the yield method to the regional stormwater dataset and provide new rankings, 
  • Estimate the presence of Aroclors in samples where congener data are available
  • Evaluate data weaknesses and recommend watersheds to resample, and
  • Classify watersheds into high, medium, and low categories for potential management.
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Jones, C.; Davis, J.; Yee, D. 2022. Strategy for In-Bay Fate Modeling to Support Contaminant and Sediment Management in San Francisco Bay. SFEI Contribution No. 1090. San Francisco Estuary Institute: Richmond, California.

This report presents a strategy and multi-year workplan for modeling polychlorinated biphenyls (PCBs), contaminants of emerging concern (CECs), and sediment in San Francisco Bay (the Bay). Robust in-Bay fate modeling is needed to address priority management questions that have been identified for these constituents.

The strategy for in-Bay modeling presented in this report is a major element of a broader, integrated strategy that is being developed across RMP Workgroups for modeling contaminants flowing from the Bay watersheds and other pathways into the Bay. The broader project is expected to yield an integrated strategy in 2022, followed by implementation of a pilot effort in 2023. Coordination of the in-Bay modeling effort with the broader integrated strategy and other modeling work (e.g., nutrient modeling under the Nutrient Management Strategy) will be critical to optimizing use of the funds allocated to modeling.

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Mendez, M.; Grosso, C.; Lin, D. 2022. Summary and Evaluation of Bioaccumulation Tests for Total Polychlorinated Biphenyls (PCBs) Conducted by San Francisco Bay Dredging Projects. SFEI Contribution No. 1092. San Francisco Estuary Institute: Richmond, California.

The Dredged Material Management Office (DMMO) is responsible for annually approving dredging and disposal of millions of cubic yards of sediment to maintain safe navigation in San Francisco Bay. Dredged sediment is characterized for physical, chemical, and biological characteristics to ensure sediment disposed of in the Bay or at beneficial use locations does not cause adverse environmental impacts. Bioaccumulation thresholds and total maximum daily loads (TMDLs) have been established for several contaminant classes, including PCBs, and are used by the DMMO to determine whether sediment contaminant levels trigger subsequent bioaccumulation testing. Sediment with contaminant concentrations above any TMDL levels cannot be disposed of within the Bay but may be further evaluated for upland reuse and ocean disposal. The objective of this study was to evaluate PCB bioaccumulation data from navigational dredging projects to assess the existence of correlations between sediment chemistry and bioaccumulation test results. The motivation for this study was to determine whether the current PCB bioaccumulation trigger is effective in differentiating sediment bioaccumulation concerns. The DMMO may use the results of this study to inform evaluation requirements for PCBs, particularly in support of modifying the terms of the Long-term Management Strategy for San Francisco Bay (LTMS) programmatic Essential Fish Habitat (EFH) agreement concerning PCB bioaccumulation testing. 

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Wang, M.; Kinyua, J.; Jiang, T.; Sedlak, M.; McKee, L. J. .; Fadness, R.; Sutton, R.; Park, J. - S. 2022. Suspect Screening and Chemical Profile Analysis of Storm-Water Runoff Following 2017 Wildfires in Northern California. Environmental Toxicology and Chemistry . SFEI Contribution No. 1089.

The combustion of structures and household materials as well as firefighting during wildfires lead to releases of potentially hazardous chemicals directly into the landscape. Subsequent storm-water runoff events can transport wildfire-related contaminants to downstream receiving waters, where they may pose water quality concerns. To evaluate the environmental hazards of northern California fires on the types of contaminants in storm water discharging to San Francisco Bay and the coastal marine environment, we analyzed storm water collected after the northern California wildfires (October 2017) using a nontargeted analytical (NTA) approach. Liquid chromatography quadrupole time-of-flight mass spectrometric analysis was completed on storm-water samples (n = 20) collected from Napa County (impacted by the Atlas and Nuns fires), the city of Santa Rosa, and Sonoma County (Nuns and Tubbs fires) during storm events that occurred in November 2017 and January 2018. The NTA approach enabled us to establish profiles of contaminants based on peak intensities and chemical categories found in the storm-water samples and to prioritize significant chemicals within these profiles possibly attributed to the wildfire. The results demonstrated the presence of a wide range of contaminants in the storm water, including surfactants, per- and polyfluoroalkyl substances, and chemicals from consumer and personal care products. Homologs of polyethylene glycol were found to be the major contributor to the contaminants, followed by other widely used surfactants. Nonylphenol ethoxylates, typically used as surfactants, were detected and were much higher in samples collected after Storm Event 1 relative to Storm Event 2. The present study provides a comprehensive approach for examining wildfire-impacted storm-water contamination of related contaminants, of which we found many with potential ecological risk. Environ Toxicol Chem 2022;00:1–14. © 2022 SETAC

Wheeler, M.; Stoneburner, L.; Spotswood, E.; Grossinger, R.; Barar, D.; Randisi, C. 2022. An Urban Forest Master Plan for East Palo Alto. SFEI Contribution No. 1071. San Francisco Estuary Institute: Richmond, CA.
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Yee, D. 2021. 2019 RMP Data Quality Assurance Report. San Francisco Estuary Institute: Richmond, CA.

This memo provides a high-level summary of the quality assurance assessment for data reported by the RMP.  In 2019, fish tissue samples were collected from nine Bay/Delta areas and three additional wetland/slough areas for the Regional Monitoring Program for Water Quality in San Francisco Bay (RMP). General descriptions of the sample collection methods are provided in the RMP Quality Assurance Program Plan, cruise plans, cruise reports, and field sampling reports. These documents are available from the SFEI website (http://www.sfei.org/content/status-and-trends-monitoring-documents).

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2021. 2020-21 RMP North Bay Selenium Study. SFEI Contribution No. 1052. San Francisco Estuary Institute: Richmond, CA.

This report details activities associated with the Regional Monitoring Program North Bay Selenium Study in 2020 and 2021. The study was designed to monitor two sites for selenium (Se) in water and clam tissue six times annually between June and February. Due to the COVID pandemic, however, four sample collection events were completed. This report outlines the sampling activities, personnel, and site locations monitored for the project.


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2021. 2020 Bay Margins Sediment Study Cruise Plan. SFEI Contribution No. 1073. San Francisco Estuary Institute: Richmond, California.

This report details plans associated with sediment sampling for the Bay Margins Sediment Study for the Regional Monitoring Program for Water Quality in San Francisco Bay (RMP). Bay margins (i.e., mud flats and adjacent shallow areas of the Bay) are productive and highly utilized by biota of interest (humans and wildlife). This study will provide a spatially-distributed characterization of surface sediment contamination and ancillary characteristics within San Pablo Bay, Suisun Bay, and Carquinez Strait margin areas. This study builds on two previous studies to characterize surface sediment contamination in Central and South Bays.

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Yee, D.; Wong, A.; Weaver, M. 2021. 2021 Quality Assurance Program Plan for the Regional Monitoring Program for Water Quality in San Francisco Bay. SFEI Contribution No. 1048. San Francisco Estuary Institute: Richmond, California.
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Foley, M. 2021. 2021 RMP Multi-Year Plan. SFEI Contribution No. 1027. San Francisco Estuary Institute: Richmond, CA.
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Foley, M.; Sutton, R.; Yee, D.; Salop, P. 2021. 2021 RMP Water Cruise Plan. SFEI Contribution No. 1050. San Francisco Estuary Institute: Richmond, California.

This report details plans associated with the annual Regional Monitoring Program for Water Quality in the San Francisco Estuary (RMP) water cruise. The RMP water sampling program was redesigned in 2002 to adopt a randomized sampling design at thirty-one sites in place of the twenty-six base program stations sampled previously. In 2007, the number of sites was decreased to twenty-two stations, and it remains as such for 2021. The analytes for 2021 have been modified based on the Status and Trends (S&T) Review process that started in 2020. The analytes that are being removed from the program include selenium and methylmercury (dissolved and particulate), while bisphenols and organophosphate esters (OPEs) have been added to S&T monitoring. 

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Overdahl, K. E.; Sutton, R.; Sun, J.; DeStefano, N. J.; Getzinger, G. J.; P. Ferguson, L. 2021. Assessment of emerging polar organic pollutants linked to contaminant pathways within an urban estuary using non-targeted analysis. SFEI Contribution No. 1107. Environmental Sciences: Processes and Impacts.

A comprehensive, non-targeted analysis of polar organic pollutants using high resolution/accurate mass (HR/AM) mass spectrometry approaches has been applied to water samples from San Francisco (SF) Bay, a major urban estuary on the western coast of the United States, to assess occurrence of emerging contaminants and inform future monitoring and management activities. Polar Organic Chemical Integrative Samplers (POCIS) were deployed selectively to evaluate the influence of three contaminant pathways: urban stormwater runoff (San Leandro Bay), wastewater effluent (Coyote Creek, Lower South Bay), and agricultural runoff (Napa River). Grab samples were collected before and after deployment of the passive samplers to provide a quantitative snapshot of contaminants for comparison. Composite samples of wastewater effluent (24 hours) were also collected from several wastewater dischargers. Samples were analyzed using liquid-chromatography coupled to high resolution mass spectrometry. Resulting data were analyzed using a customized workflow designed for high-fidelity detection, prioritization, identification, and semi-quantitation of detected molecular features. Approximately 6350 compounds were detected in the combined data set, with 424 of those compounds tentatively identified through high quality spectral library match scores. Compounds identified included ethoxylated surfactants, pesticide and pharmaceutical transformation products, polymer additives, and rubber vulcanization agents. Compounds identified in samples were reflective of the apparent sources and pathways of organic pollutant inputs, with stormwater-influenced samples dominated by additive chemicals likely derived from plastics and vehicle tires, as well as ethoxylated surfactants.

Spotswood, E.; Beller, E. E.; Grossinger, R. M.; Grenier, L.; Heller, N.; Aronson, M. 2021. The biological deserts fallacy: Cities in their landscapes contribute more than we think to regional biodiversity. BioScience 71 (2) . SFEI Contribution No. 1031.

Cities are both embedded within and ecologically linked to their surrounding landscapes. Although urbanization poses a substantial threat to biodiversity, cities also support many species, some of which have larger populations, faster growth rates, and higher productivity in cities than outside of them. Despite this fact, surprisingly little attention has been paid to the potentially beneficial links between cities and their surroundings.

We identify five pathways by which cities can benefit regional ecosystems by releasing species from threats in the larger landscape, increasing regional habitat heterogeneity and genetic diversity, acting as migratory stopovers, preadapting species to climate change, and enhancing public engagement and environmental stewardship. Increasing recognition of these pathways could help cities identify effective strategies for supporting regional biodiversity conservation and could provide a science-based platform for incorporating biodiversity alongside other urban greening goals.

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Panlasigui, S.; Spotswood, E.; Beller, E.; Grossinger, R. 2021. Biophilia beyond the Building: Applying the Tools of Urban Biodiversity Planning to Create Biophilic Cities. Sustainability 13 (5).

In response to the widely recognized negative impacts of urbanization on biodiversity, many cities are reimagining urban design to provide better biodiversity support. Some cities have developed urban biodiversity plans, primarily focused on improving biodiversity support and ecosystem function within the built environment through habitat restoration and other types of urban greening projects. The biophilic cities movement seeks to reframe nature as essential infrastructure for cities, seamlessly integrating city and nature to provide abundant, accessible nature for all residents and corresponding health and well-being outcomes. Urban biodiversity planning and biophilic cities have significant synergies in their goals and the means necessary to achieve them. In this paper, we identify three key ways by which the urban biodiversity planning process can support biophilic cities objectives: engaging the local community; identifying science-based, quantitative goals; and setting priorities for action. Urban biodiversity planning provides evidence-based guidance, tools, and techniques needed to design locally appropriate, pragmatic habitat enhancements that support biodiversity, ecological health, and human health and well-being. Developing these multi-functional, multi-benefit strategies that increase the abundance of biodiverse nature in cities has the potential at the same time to deepen and enrich our biophilic experience in daily life.

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Moore, S.; Hale, T.; Weisberg, S. B.; Flores, L.; Kauhanen, P. 2021. California Trash Monitoring Methods and Assessments Playbook. SFEI Contribution No. 1025. San Francisco Estuary Institute: Richmond, Calif.

As municipalities and water-quality regulatory agencies have implemented programs and policies to improve management of the trash loading to storm drain conveyances, there has been increased interest in using a common set of methods to quantify the effectiveness of management actions. To create a foundation for developing a consistent, standardized approach to trash monitoring statewide, the project team performed a method comparison analysis, based on two seasons of fieldwork. This analysis facilitated the assessment of the accuracy, repeatability, and efficiency of some already developed trash monitoring methodologies already in use, as well as help to investigate a new, innovative method (cf. Fielding Testing Report on trashmonitoring.org). Methods developed by the Bay Area Stormwater Management Agencies Association (BASMAA) for use in the San Francisco Bay Area were compared to methods developed by the Southern California Stormwater Monitoring Coalition (SMC) for use in coastal southern California. One of the chief goals of these comparisons was to understand the similarities and differences between the already existing methods for detecting, quantifying, and characterizing trash in selected environments. Readers will find that the data bear out remarkable levels of accuracy and precision with quantitative metrics that help to align methods and management concerns. Furthermore, the degree of correlation among tested methods were especially high, offering greater opportunities for inter-method comparisons.

The findings of this project are intended for use by public agencies, non-profit organizations, private consultants, and all of their various partners in informing a statewide effort to adopt rigorous, standardized monitoring methods to support the State Water Board’s Trash Amendments. Over the next couple of decades, such public mandates will require all water bodies in California to achieve water quality objectives for trash.

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Lowe, S.; Pearce, S.; Kauhanen, P.; Collins, J.; Titus, D. 2021. Coyote Creek Watershed Reassessment 2020: 10-Year Reassessment of the Ecological Condition of Streams Applying the California Rapid Assessment Method, Santa Clara County, California. SFEI Contribution No. 1043. San Francisco Estuary Institute: Richmond. CA. p 131.

This report describes the amount and distribution of aquatic resources in the Coyote Creek watershed, Santa Clara County, California, and presents the first reassessment of stream ecosystem conditions using a watershed approach and the California Rapid Assessment Method (CRAM). Field work was conducted in 2020, ten years after the baseline watershed assessment completed in 2010.

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Panlasigui, S.; Baumgarten, S.; Spotswood, E. 2021. E-Bikes and Open Space: The Current State of Research and Management Recommendations. SFEI Contribution No. 1064. San Francisco Estuary Institute: Richmond, CA.
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SFEI. 2021. Ecotone levees and wildlife connectivity: A technical update to the Adaptation Atlas. SFEI Contribution No. 1037. San Francisco Estuary Institute: Richmond, CA.
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Moore, S.; Hale, T.; Weisberg, S. B.; Flores, L.; Kauhanen, P. 2021. Field Testing Report: California Trash Monitoring Methods. SFEI Contribution No. 1026. San Francisco Estuary Institute: Richmond, Calif.

Trash has received renewed focus in recent years as policy makers, public agencies, environmental organizations, and community groups have taken many steps towards trash quantification and management across California. The range of management actions is matched by the diversity of monitoring approaches, designed to determine key attributes associated with trash pollution on California’s lands and in its waterways.

This report describes the field testing associated with a project designed to validate the accuracy, precision, and practicality of several trash monitoring methods, practiced across the state. Additionally, the project measured the efficacy of a novel monitoring method designed to detect trash via remote sensing and machine learning. Readers will find details about each respective method -- the specific approach to
landscape characterization, the qualitative or quantitative measures undertaken, the team-based quality assurance for data collection -- as well as the approach that the testing team adopted to ensure efficient, accurate, and useful validation of the methods.

Because the validation efforts integrated multiple methods, using multiple teams at a selection of common sites, the field testing report yields useful statistical information not only about each method individually, but about the comparability of the results. The report illustrates the
correlation factor associated with different forms of trash metrics, associated with different methods practiced on the same assessment sites. The results illustrated a generally high degree of correlation among different methods, which promises opportunities to compare results meaningfully across methods.

Furthermore, this field testing report provides quantitative measures to illustrate the repeatability of each method, the differences and insights yielded by assessment site sizing criteria varying among methods, the transferability / teach-ability of each method among trash monitoring practitioners, and how the degrees of accuracy might aid programs in performing mass balance analysis of known sources
to trash detected in a given site.

Regarding innovation, the project team leveraged multiple on-the-ground methods and special testing scenarios to compare conventional and novel (aerial) assessments to measure the relative accuracy and precision of this emergent technology that might address some of the resource constraints that currently limit the broader or more frequent deployment of conventional trash assessment methods. The analyses captured in this field testing report offer specific quantitative measures of the accuracy (bias), precision (repeatability), practicality and cost associated with each method. This information is subsequently used to inform a companion summary analysis found in the Trash Monitoring Playbook, which is designed to evaluate the applicability of the monitoring methods to address classes of
monitoring questions.

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Dusterhoff, S.; Shaw, S.; McKnight, K. 2021. Flood Control Channel Classification Scheme for the San Francisco Bay Region. Josh Collins, Ed.. San Francisco Bay Region Flood Control Channel Classification . SFEI Contribution No. 1046. San Francisco Estuary Institute: Richmond, CA.
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Chang, D.; Richardot, W.; Miller, E.; Dodder, N.; Sedlak, M.; Hoh, E.; Sutton, R. 2021. Framework for nontargeted investigation of contaminants released by wildfires into stormwater runoff: Case study in the northern San Francisco Bay area. Integrated Environmental Assessment and Management . SFEI Contribution No. 1044.

Wildfires can be extremely destructive to communities and ecosystems. However, the full scope of the ecological damage is often hard to assess, in part due to limited information on the types of chemicals introduced to affected landscapes and waterways. The objective of this study was to establish a sampling, analytical, and interpretive framework to effectively identify and monitor contaminants of emerging concern in environmental water samples impacted by wildfire runoff. A nontargeted analysis consisting of comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC × GC/TOF-MS) was conducted on stormwater samples from watersheds in the City of Santa Rosa and Sonoma and Napa Counties, USA, after the three most destructive fires during the October 2017 Northern California firestorm. Chemicals potentially related to wildfires were selected from the thousands of chromatographic features detected through a screening method that compared samples from fire-impacted sites versus unburned reference sites. This screening led to high confidence identifications of 76 potentially fire-related compounds. Authentic standards were available for 48 of these analytes, and 46 were confirmed by matching mass spectra and GC × GC retention times. Of these 46 compounds, 37 had known commercial and industrial uses as intermediates or ingredients in plastics, personal care products, pesticides, and as food additives. Nine compounds had no known uses or sources and may be oxidation products resulting from burning of natural or anthropogenic materials. Preliminary examination of potential toxicity associated with the 46 compounds, conducted via online databases and literature review, indicated limited data availability. Regional comparison suggested that more structural damage may yield a greater number of unique, potentially wildfire-related compounds. We recommend further study of post-wildfire runoff using the framework described here, which includes hypothesis-driven site selection and nontargeted analysis, to uncover potentially significant stormwater contaminants not routinely monitored after wildfires and inform risk assessment. 

Zi, T.; Kauhanen, P.; Whipple, A.; Mckee, L. 2021. Green Stormwater Infrastructure Planning-level Analysis for Livermore-Amador Valley. SFEI Contribution No. 1063. San Francisco Estuary Institute: Richmond, Calif.

Report CoverThis effort is intended to provide planning-level regional guidance for placement of green stormwater infrastructure (GSI) in Livermore-Amador Valley. This work identifies potential GSI locations and quantifies contaminant load and stormwater runoff volume reduction benefits through the application of GreenPlan-IT, a planning tool developed by the San Francisco Estuary Institute and regional partners. Ultimately, the urban greening analysis presented in this report is intended to help enhance stream and watershed resilience, reduce peak flows, and improve water quality.

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Lowe, J.; Plane, E.; Gonzalez, J.; Salomon, M. 2021. Guidance for Restoration of Natural and Nature-Based Features in the Wetland-Upland Transition Zone. San Francisco Estuary Institute, California State Coastal Conservancy: Richmond, CA.
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Zhu, X.; Munno, K.; Grbic, J.; Werbowski, L. M.; Bikker, J.; Ho, A.; Guo, E.; Sedlak, M.; Sutton, R.; Box, C.; et al. 2021. Holistic Assessment of Microplastics and Other Anthropogenic Microdebris in an Urban Bay Sheds Light on Their Sources and Fate. Environmental Science and Technology Water . SFEI Contribution No. 1060.

The physical and chemical properties of microplastics and their environmental distributions may provide clues about their sources and inform their fate. We demonstrate the value of extensive monitoring of microplastics in an urban bay, San Francisco Bay. Surface water, fish, sediment, stormwater runoff, and treated wastewater were sampled across the bay and adjacent national marine sanctuaries (NMS). We found microplastics and other anthropogenic microdebris (“microdebris”) in all sample types. Concentrations were higher in the bay than in the NMS, and within the bay, concentrations were higher during the wet season than during the dry season. The fate of microdebris varied depending on their morphologies and densities: fibers were dominant in fish, black rubbery fragments were common in sediment, as were fibers, while buoyant fragments and fibers were widely observed in surface waters. Notably, we found large amounts of black rubbery fragments, an emerging contaminant, in stormwater. Moreover, stormwater was a significant pathway of microdebris, with concentrations roughly 140 times greater than those found in wastewater, which was dominated by fibers. Overall, we demonstrate the value of multimatrix regional monitoring to evaluate the sources and fate of microplastics, which can inform effective mitigation for other urban bays around the world.


Cloern, J. E.; Safran, S. M.; Vaughn, L. Smith; Robinson, A.; Whipple, A.; Boyer, K. E.; Drexler, J. Z.; Naiman, R. J.; Pinckney, J. L.; Howe, E. R.; et al. 2021. On the human appropriation of wetland primary production. Science of the Total Environment 785.

Humans are changing the Earth's surface at an accelerating pace, with significant consequences for ecosystems and their biodiversity. Landscape transformation has far-reaching implications including reduced net primary production (NPP) available to support ecosystems, reduced energy supplies to consumers, and disruption of ecosystem services such as carbon storage. Anthropogenic activities have reduced global NPP available to terrestrial ecosystems by nearly 25%, but the loss of NPP from wetland ecosystems is unknown. We used a simple approach to estimate aquatic NPP from measured habitat areas and habitat-specific areal productivity in the largest wetland complex on the USA west coast, comparing historical and modern landscapes and a scenario of wetland restoration. Results show that a 77% loss of wetland habitats (primarily marshes) has reduced ecosystem NPP by 94%, C (energy) flow to herbivores by 89%, and detritus production by 94%. Our results also show that attainment of habitat restoration goals could recover 12% of lost NPP and measurably increase carbon flow to consumers, including at-risk species and their food resources. This case study illustrates how a simple approach for quantifying the loss of NPP from measured habitat losses can guide wetland conservation plans by establishing historical baselines, projecting functional outcomes of different restoration scenarios, and establishing performance metrics to gauge success.

Klasios, N.; De Frond, H.; Miller, E.; Sedlak, M.; Rochman, C. M. 2021. Microplastics and other anthropogenic particles are prevalent in mussels from San Francisco Bay, and show no correlation with PAHs. Environmental Pollution 271.

Microplastics are an emerging contaminant of high environmental concern due to their widespread distribution and availability to aquatic organisms. Filter-feeding organisms like bivalves have been identified as particularly susceptible to microplastics, and because of this, it has been suggested bivalves could be useful bioindicators of microplastic pollution in ecosystems. We sampled resident mussels and clams from five sites within San Francisco Bay for microplastics and other anthropogenic microparticles. Cages of depurated mussels (denoted transplants) were also deployed at four sites in the Bay for 90 days to investigate temporal uptake of microplastics and microparticles. Because microplastics can sorb PAHs, and thus may act as a source of these chemicals upon ingestion, transplant mussels and resident clams were also analyzed for PAHs. We found anthropogenic microparticles in all samples at all sites, some of which were identified as microplastics. There was no statistical difference between the mean number of microparticles found in resident and transplant species. There were significant site-specific differences among microparticle abundances in the Bay, with the highest abundances observed in the South Bay. No correlation was found between the number of microparticles and the sum concentrations of PAHs, priority PAHs, or any individual PAH, suggesting the chemical concentrations observed reflect broader chemical trends in the Bay rather than direct exposure through microplastic ingestion. The pattern of spatial distribution of microparticles in transplanted mussels matched that of sediment samples from the Bay, suggesting bivalves could be a useful bioindicator of microplastic abundances in sediment, but not surface water.

Spotswood, E.; Benjamin, M.; Stoneburner, L.; Wheeler, M. 2021. Nature inequity and higher COVID-19 case rates in less green neighbourhoods in the United States. Nature Sustainability 4 (10).

Nature inequity and higher COVID-19 case rates in less green neighbourhoods in the United StatesUrban nature—such as greenness and parks—can alleviate distress and provide space for safe recreation during the COVID-19 pandemic. However, nature is often less available in low-income populations and communities of colour—the same communities hardest hit by COVID-19. In analyses of two datasets, we quantified inequity in greenness and park proximity across all urbanized areas in the United States and linked greenness and park access to COVID-19 case rates for ZIP codes in 17 states. Areas with majority persons of colour had both higher case rates and less greenness. Furthermore, when controlling for sociodemographic variables, an increase of 0.1 in the Normalized Difference Vegetation Index was associated with a 4.1% decrease in COVID-19 incidence rates (95% confidence interval: 0.9–6.8%). Across the United States, block groups with lower-income and majority persons of colour are less green and have fewer parks. Our results demonstrate that the communities most impacted by COVID-19 also have the least nature nearby. Given that urban nature is associated with both human health and biodiversity, these results have far-reaching implications both during and beyond the pandemic.

Related data: https://www.sfei.org/data/nature-equity-covid-2021


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Davis, J.; Buzby, N. 2021. PCBs in Shiner Surfperch in Priority Margin Areas of San Francisco Bay. SFEI Contribution No. 1054.

Conceptual models developed for selected San Francisco Bay margin areas (referred to as priority margin units, or PMUs) have identified shiner surfperch as a crucial indicator of PCB impairment, due to their explicit inclusion as an indicator species in the PCBs TMDL, importance as a popular sport fish species, tendency to accumulate high PCB concentrations, site fidelity, and other factors. The conceptual models recommend periodic monitoring of shiner surfperch to track trends in the PMUs, and as the ultimate indicator of progress in reduction of impairment. The objectives of this study were to 1) establish baselines for long-term monitoring of PCB concentrations in shiner surfperch in four PMUs, and 2) understand local spatial variation in shiner PCB concentrations to support optimization of the long-term sampling design. This study also provided valuable information on the presence of shiner surfperch and other species in the PMUs. 

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Gilbreath, A.; McKee, L.; Hunt, J. 2021. Pollutants of Concern Reconnaissance Monitoring Progress Report, Water Years 2015-2020. SFEI Contribution No. 1061. San Francisco Estuary Institute: Richmond, CA.

The San Francisco Bay polychlorinated biphenyl (PCB) and mercury (Hg) total maximum daily loads (TMDLs) call for implementation of control measures to reduce PCB and Hg loads entering the Bay via stormwater. In 2009, the San Francisco Bay Regional Water Quality Control Board (Regional Water Board) issued the first Municipal Regional Stormwater Permit (MRP). This MRP contained a provision aimed at improving information on stormwater pollutant loads in selected watersheds (Provision C.8.) and piloted a number of management techniques to reduce PCB and Hg loading to the Bay from smaller urbanized tributaries (Provisions C.11. and C.12.). To address C8, a previously developed fixed station loads monitoring technique was refined that incorporated turbidity and stage sensors recording at 5-15 minute intervals with the collection of velocity and water samples using both manual and auto sampling techniques to compute loads. In 2015, the Regional Water Board issued the second iteration of the MRP. “MRP 2.0” placed an increased focus on identifying those watersheds, source areas, and source properties that are potentially the most polluted and are therefore most likely to be cost-effective areas for addressing load-reduction requirements.

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