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  • Bioaccumulation study informs health risks from sediment

    November 21, 2016:

    SCCWRP and its partners have completed a comprehensive investigation into how sediment contamination is transferred through Southern California marine food webs, a study that has enabled scientists to close key data gaps and build more accurate models for estimating health risks to wildlife and humans across coastal California.

    The three-year study, which was finalized in October, was conducted in San Diego Bay; it already is being used to refine and calibrate a standardized sediment assessment framework under development for California’s coastal embayments to extend greater protections to human health. The statewide Sediment Quality Objective (SQO) for protection of human health – which relies on bioaccumulation models to explain how contaminants travel through food webs – will help inform sediment clean-up targets and other management actions for embayments.

    The study involved linking major contaminants found in San Diego Bay sediment – including PCBs, pesticides and trace metals – to the contaminants that were found to be bioaccumulating in organisms throughout the marine food web, from sediment-dwelling organisms to seabirds. Sediment contaminants are transferred through food webs by each successive predator that consumes its prey.

    The study found that all types of sportfish examined had contamination levels that exceeded statewide safe-eating guidelines for humans, and seabirds also were potentially at risk from eating fish that had mercury and PCB contamination.

    However, the health risks from sediment contamination were low, and conditions have improved in recent years, according to the study. For example, PCB contamination in seafood has dropped two- to five-fold over the past 15 years.

    San Diego Bay environmental managers will use the study’s findings to take more effective, targeted actions to continue to improve the bay’s sediment quality.

    In early 2017, the State Water Board is expected to release a draft of the California SQO assessment framework for protection of human health; the framework has been improved using data obtained from the San Diego Bay bioaccumulation study and other case studies. The counterpart to the SQO human health framework – the SQO assessment framework for the protection of sediment-dwelling aquatic life – was co-developed by SCCWRP and adopted by the State Water Board in 2009.


    A researcher collects abandoned bird eggs from the California least tern in South
    San Diego Bay's Salt Works area. Field sampling was conducted for organisms at multiple
    levels of the marine food web for a San Diego Bay contaminant bioaccumulation study. 
    (Courtesy of Lea Squires)


    The San Diego Bay bioaccumulation study analyzed 209 tissue samples (plotted on map)
    from across San Diego Bay 64 sediment samples. The study was done in partnership
    with the Southern California Bight 2013 Regional Monitoring Program, San Diego 
    Regional Harbor Monitoring Program, and City of San Diego.


    Researchers collected abandoned eggs from the California least tern and other
    bird species during a bioaccumulation study in San Diego Bay.

  • Workshop highlights need for improved science to manage 'climate-ready' bar-built estuaries

    November 14, 2016:

    SCCWRP in September helped kick-start a wide-ranging discussion with California water-quality and natural resource managers about how to more effectively manage a common type of coastal estuary known as a bar-built estuary that is periodically cut off from the open ocean through the natural build-up of sandy barriers.

    The intermittently open phenomenon, which affects about 90% of the state’s 400-plus coastal estuaries, is intrinsic to bar-built estuaries, but the hydrologic isolation makes them particularly vulnerable to the impacts of land-based pollution and global climate change. Anytime that bar-built estuaries are shut off from dynamically mixing with the open ocean for extended periods, they can experience a precipitous decline in water quality that threatens the health of their inhabitants.

    Water-quality managers commonly breach the sandy berms of bar-built estuaries to flush out these systems and boost water quality, but this strategy is at odds with efforts to restore and maintain bar-built estuaries in a more ecologically natural state. The endangered tidewater goby, for example, is a fish that depends on the periodic closing of bar-built estuaries to complete their lifecycle.

    During the workshop, held in September at SCCWRP, participants agreed that the inherent tension between water-quality goals and preservation goals for bar-built estuaries will intensify in the coming decades. Climate change is expected to trigger prolonged drought and more frequent storm surges, which will tend to strengthen the sandy berms of bar-built estuaries and keep them shut off from the open ocean for longer periods of time.

    To enable managers to take a “climate-ready” approach to bar-built estuary management, workshop participants emphasized the need for improved science to inform management decisions. In particular, more ecologically relevant water quality indicators and targets are needed.

    Already, researchers have begun developing the science to help bar-built estuary managers balance water-quality and preservation goals.

    At the workshop, SCCWRP presented the findings of a recent study that found that bar-built estuary managers aren’t using ecologically relevant thresholds for dissolved oxygen levels in their decision-making. In fact, SCCWRP and its partners found that bar-built estuaries in reference condition failed to meet existing objectives for dissolved oxygen (DO) 26% to 60% of the time, signaling that existing DO objectives require updating to be useful in guiding management decision-making.

    SCCWRP also highlighted its recently completed effort to develop macroalgal numeric targets for bar-built estuaries – an example of a more ecologically relevant indicator.
    Workshop participants agreed that researchers should continue down this path, including improving on existing tools for bottom-dwelling estuarine organisms to measure overall ecological health, and using innovative modeling and conceptual frameworks to adaptively manage bar-built estuaries.

    Researchers’ long-term goal is to develop a full suite of assessment tools that can help managers make science-informed decisions about how best to protect both water quality and habitat condition in intermittently open estuaries, especially in light of climate change. This management toolbox will be modeled after the robust, multi-pronged approaches developed in recent years to improve management of California streams.

    For more information, contact Dr. Martha Sutula and Dr. Eric Stein.


    Malibu Lagoon in Los Angeles County is a bar-built estuary that is periodically cut off
    from the ocean by the natural build-up of a sandy barrier at its mouth. This hydrologic 
    isolation makes it particularly vulnerable to the impacts of land-based pollution and climate change.


    Coastal estuaries like San Mateo Lagoon in San Diego County that are cut off from
    the ocean by naturally forming sand barriers often face water-quality challenges.
    Although artificially breaching the estuary mouth can restore water quality, this
    management strategy is at odds with goals to restore and maintain the site in a more
    ecologically natural state. Improved science can help bar-built estuary managers make
    better decisions about the management of these ecologically sensitive systems.

  • Scientists, managers lay foundation for developing acidification criteria at workshop

    November 07, 2016:

    Scientists and coastal managers from across the West Coast began laying the groundwork for the development of ecologically relevant criteria for coastal ocean acidification during a two-day workshop in October at Stanford University.

    At the workshop, titled An Uncommon Dialogue: Ocean Acidification: Setting Water Quality Goals, participants sought to develop consensus around how to apply ocean acidification science to improve management of the coastal ocean, as well as what research is most needed to support development of management criteria. The October 17-18 workshop was hosted by Stanford University’s Woods Institute for the Environment, the Center for Ocean Solutions, the California Ocean Protection Council and SCCWRP.
    In particular, workshop participants stressed the need for improved understanding of how the chemical indicators of ocean acidification (e.g., carbonate saturation state, pH) relate to how biological communities respond to acidification (e.g., free-swimming pteropods, or sea snails).

    The pH-based criteria that West Coast managers have been using for decades to protect ocean health are based on outdated science, with marine communities harmed at pH thresholds that fall within the criteria’s range.

    Furthermore, because development of ocean acidification criteria to manage coastal waters is still years into the future, participants discussed how they could advance acidification science to a point where West Coast managers could use it to improve their monitoring and management practices in the short term. For example, participants explored how to use observational acidification data in tandem with a West Coast-wide ocean acidification modeling effort to help quantify natural variability in ocean state.

    The timely workshop follows on the heels of two new state laws (SB 1363 and AB 2139) that direct the California Ocean Protection Council and other state agencies to implement the recommendations of a 20-member West Coast advisory panel of leading ocean scientists. The West Coast Ocean Acidification and Hypoxia Science Panel released a series of short- and long-term management actions for combatting ocean acidification in April; SCCWRP’s Dr. Steve Weisberg and Dr. Martha Sutula were among the panelists.

    Already, the California Ocean Protection Council has responded to the new legislative directive by announcing funding for a broad suite of acidification-related initiatives, including a SCCWRP-led effort to develop a synthesis of existing science regarding ocean acidification indicators and their response thresholds, and an expansion of the ongoing West Coast acidification modeling effort. The West Coast acidification model, which is being co-developed by SCCWRP, seeks to understand which marine habitats are most vulnerable to acidification and to what extent local, land-based sources of pollution are exacerbating acidification.

    For more information, contact Dr. Steve Weisberg



    Acidification of West Coast ocean waters is making it harder for marine organisms
    like the pteropod, or sea snail, above, to maintain its calcium carbonate shell. The shell
    of a healthy pteropod, top, looks visibly different from a pteropod that's been stressed
    by acidification, bottom.

  • Surfer rainfall study helps focus water-quality discussion

    September 12, 2016:

    SCCWRP and its partners have completed a three-year epidemiological study examining the health impacts of entering coastal waters during and shortly after rainfall, a study that has raised important public policy questions about whether existing water-quality standards are protecting beachgoers during wet weather.

    The Surfer Health Study, which tracked the illness rates of 654 San Diego-area surfers during the rainy winter season, found that surfers experienced increased rates of both gastrointestinal illness and other illness symptoms when they surfed during rain events and/or in the three days that followed. 

    However, when the illness data were correlated with quantitative measurements of aquatic microbial contamination at two popular San Diego surfing spots, the rate at which surfers contracted gastrointestinal illness was lower than the illness rate predicted under federal guidelines. The guidelines, which were issued by the U.S. Environmental Protection Agency in 2012, predict the relationship between gastrointestinal illness rates and corresponding microbial contamination levels.

    Given these findings, water-quality managers are now tasked with determining what additional clean-up actions are needed to reduce the illness rates documented in San Diego.

    Rainfall makes Southern California’s coastal zone particularly susceptible to waterborne contamination, as the pathogens that can make people sick wash off the land and travel through storm drains to the beach. Although most Southern California beachgoers heed warnings by public health officials to stay out of the water following rainfall, surfers are a notable exception; thousands are attracted to the favorable surf conditions that accompany storm events. 

    During the study, which was conducted during the winters of 2013-14 and 2014-15, San Diego surfer volunteers were asked to use a smartphone app to confidentially  
    report their daily surfing activities and symptoms of illness. They received gift certificates to a surfing retailer for their participation. 

    Study participants logged a combined 10,081 surfing sessions; 13% of these sessions took place during wet-weather conditions, making the beach epidemiology study one of the largest of its kind in the past 30 years.

    The study documented an excess gastrointestinal illness risk of 12 cases per 1,000 for surfers who entered the water in wet weather, for a total of 30 cases per 1,000. The EPA’s water-quality criteria, however, specify that there are to be no more than 32 to 36 excess cases per 1,000.

    The full epidemiology study has been published on SCCWRP’s website. For more information, contact Ken Schiff.  

    Surfers paddle away from the shore during a sunny winter morning at Ocean Beach in San Diego,
    just one day after a torrential downpour. Scientists want to know the extent to which rainfall runoff
    in coastal ocean waters is making ocean bathers sick.

    San Diego's Tourmaline Surfing Park is at the receiving end of a storm drain channel, making it
    susceptible to land-based runoff during rainfall.

  • Method comparison study seeks to assess utility of using DNA to identify stream algae

    August 05, 2016:

    SCCWRP and its partners have launched a first-of-its-kind study to determine whether DNA-based methods can reliably be used to identify algae in wadeable streams across California, a finding that could pave the way for the incorporation of molecular technology into stream bioassessment monitoring statewide.

    Stream managers across Southern California already use the composition of stream algal communities to evaluate overall water body condition, but these assessments are dependent on trained taxonomists to identify algae samples individually. This manual identification process is labor-intensive, costly and prone to backlogs.

    Switching to an algal analysis method that allows algae samples to be identified through DNA sequencing could reduce dependence on a limited supply of algal taxonomists, as well as provide important new insights about novel algae species and their habitats. 

    In January, SCCWRP and its partners began laying the groundwork to compare the effectiveness of morphology vs. DNA-based algae identification methods. The study is ongoing.

    The need for improved stream algae bioassessment methods is growing in California. For the past six years, state water officials have been working to develop a statewide stream biointegrity and nutrient policy that is expected to rely, in part, on algae-based bioassessments. 

    Algal communities are valuable indicators of human impacts to streams because they are highly sensitive to physical, hydrological and geochemical changes to their environment. Excessive nutrient inputs, for example, can trigger harmful algal blooms (HABs).

    Vetting DNA-based algae bioassessment methods also could benefit the state’s Surface Water Ambient Monitoring Program (SWAMP), which is developing an algae-based stream scoring tool comparable to the California Stream Condition Index (CSCI). The CSCI, which was co-developed by SCCWRP, uses aquatic insects and other benthic invertebrates as indicators of stream condition. The statewide algal index is being built to complement the CSCI, providing an additional line of evidence for evaluating stream health.

    For the method comparison study, SCCWRP and its partners plan to assess the performance of the DNA-based identification methods across a wide range of geographic and geochemical settings. Algae samples are being collected by the Southern California Stormwater Monitoring Coalition, the San Francisco Bay Regional Monitoring Coalition, the statewide Reference Condition Management Program, and the statewide Perennial Stream Assessment. In addition, the Santa Margarita River – a watershed heavily impacted by nutrient loading – is being sampled to assess method performance through a full algae bloom-and-bust seasonal cycle.

    Study findings are expected to be released in late 2017.

    For more information, contact Dr. Susanna Theroux


    SCCWRP's Justin Vanderwal and Lisa Zumwalde wade into the Santa Margarita River 
    to collect samples of greenish algal blooms. SCCWRP and its partners are sampling the
    Santa Margarita River algae through a full boom-and-bust seasonal cycle, which will 
    provide key insights into whether DNA-based methods can reliably be used to identify 
    the algal species present.


    SCCWRP's Mayra Molina collects a sample of water in the Santa Margarita River that runs 
    through Riverside and San Diego counties. SCCWRP and its partners are sampling algae 
    in this stream and dozen of others across California for a study that will determine the
    reliability and effectiveness of using DNA-based methods to identify stream algae.

  • Cell bioassays could be effective at screening for potential harm in fish

    August 05, 2016:

    SCCWRP and its partners at the University of Florida have demonstrated in a proof-of-concept study that biological assays built with engineered human cells have the potential to be effective at screening for potential biological harm in fish exposed to differing levels of estrogen-mimicking chemicals.

    The finding, obtained in May, involved showing that there is a strong correlation between the way that engineered human cells respond to increasing levels of chemical contaminants, and the way that inland silverside fish experience increasingly severe biological effects when exposed to the same contamination.

    The ongoing linkage study – the first of its kind in a coastal marine environment – provides compelling evidence that commercially available cell bioassays are a viable technology for screening receiving waters for potentially harmful levels of CECs. Cell bioassays are commonly used in pharmaceutical and food-industry applications to rapidly screen a wide variety of chemicals for potential toxicity. 

    SCCWRP and researchers around the world are interested in adapting cell bioassays into a viable CEC screening tool because traditional methods for monitoring the impacts of CECs on aquatic life – such as targeted chemical analysis and whole-organism toxicity testing – tend to be comparatively labor-intensive and costly. These methods also tend to be unable to detect all chemicals of concern, whereas a bioassay is designed to detect dozens of chemicals that share similar biochemical properties.

    The next step in the study is to zero in on the precise chemical concentration at which the cell bioassays begin to detect an adverse biological response in fish. Knowing where this threshold lies is crucial to develop a long-term monitoring and management strategy.

    Over the long term, researchers hope to develop new bioassays and/or adapt commercially available bioassays to screen for a wide variety of CECs. Already, SCCWRP and its partners have begun working to replicate the estrogenic linkage study with glucocorticoids, a class of steroidal anti-inflammatory drugs commonly used to treat eczema and asthma. 

    For more information, contact Dr. Alvina Mehinto.

    Water-quality managers need rapid, cost-effective tools to alert them when contamination
    has the potential to adversely impact fish growth and survival. Above, the Russian River 
    in Northern California is one site where SCCWRP and its partners are testing the utility of 
    using cell bioassays to screen for potential biological effects triggered by CECs.



    SCCWRP and its partners have shown that cell-based bioassays can serve as reliable
    and sensitive tools for screening for the presence of estrogenic chemicals. Above, the cell
    assay gives a clear response signal (i.e., 50% response) in the presence of relatively low 
    concentrations of the estrogenic chemicals 17β-estradiol and nonylphenol. This response 
    was observed well before chemical concentrations rose to a level that threatens fish 
    growth and survival, indicating that cell bioassays have the potential to be adapted as an 
    effective screening method for estrogenic chemicals and other CECs.