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SETAC Minneapolis Session Summaries
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Session Summaries from SETAC Minneapolis

The recently concluded SETAC North America 38th Annual Meeting, which was held from 12–16 November 2017 in Minneapolis, Minnesota, was another successful meeting, attracting 1,812 delegates who could choose from 691 platform and 789 poster presentations. The theme of the meeting was “Toward a Superior Future: Advancing Science for a Sustainable Environment.” These session summaries provide examples of presentations and discussions during the meeting.


    Summaries Published in the December 2018 Issue (Volume 18 Issue 12)

  • Great Lakes Restoration Initiative: Occurrence and Effects of Contaminants of Emerging Concern (WATCH RECORDINGS)
    Heiko l. Schoenfuss, St. Cloud State University, Minnesota; Steven R. Corsi, USGS, Middletown, Wisconsin; Drew R. Ekman, U.S. EPA, Athens, Georgia; and Daniel L. Villeneuve, U.S. EPA, Duluth, Minnesota

    • Great Lakes Restoration Initiative-Pt 1The North American Great Lakes were the focus of a two-part spotlight session at the 2017 SETAC North American meeting held in Minneapolis, MN. The Great Lakes, one of the largest bodies of freshwater in the world, are located near the birth place of modern industrial manufacturing. As a result, they have seen their share of environmental degradation and recovery over the past two centuries. While legacy pollutants have been the focus of many prior sessions at SETAC meetings, this spotlight session examined the presence and possible biological impacts of other classes of contaminants (e.g., pharmaceuticals, personal care products, flame retardants, perfluorinated compounds, current use pesticides) that have more recently come to the attention of scientists, the public and Great Lakes managers, termed contaminants of emerging concern (CECs). Recent findings regarding the occurrence and potential ecological impacts of CECs were explored through presentations from a multi-disciplinary team of collaborating scientists across federal agencies and academic institutions. In total, sixteen speakers and four poster presenters interacted with an audience that averaged approximately 200 participants over the two half-day sessions.

      Great Lakes Restoration Initiative-Pt 2A unique aspect of this session was that the majority of presentations reported the findings of this integrated research team, funded by the Great Lakes Restoration Initiative (GLRI).  Launched in 2010 and administered by the US Environmental Protection Agency, the GLRI was created by the U.S. Congress to “accelerate efforts to protect and restore the largest system of fresh surface waters in the world.” The first of five focus areas identified under the GLRI is “Toxic Substances and Areas of Concern,” which is central to the initiative’s efforts. Several of the presentations reported data from ongoing studies that support this aspect of the GLRI, including summaries on efforts to evaluate the extent to which CECs threaten Great Lakes natural resources, as well as progress in the development of various bioeffects surveillance tools to inform natural resource management decisions.

      Speakers presented findings ranging from analytical water and sediment chemistry in the Great Lakes, to effects on multiple levels of biological organization (from metabolomics and transcriptomics to population level) in multiple taxonomic groups (from invertebrates to fish and birds). The session also featured presentations on methods for computationally integrating complex data sets and assigning hazard scores to specific contaminants or tributaries of the Great Lakes. The session was rounded out by presentations about the impacts of invasive sea lamprey in the Great Lakes and their control through the use of lampricides for over half a century.

      Several key findings emerged over the two presentations days:

      1. CECs are ubiquitous throughout Great Lakes tributaries and occur in complex mixtures that reflect surrounding land use. As a consequence, there have been promising advancements in statistical model development for predicting the occurrence of CECs based on watershed attributes. These models provide a new set of tools for assisting resource managers in identifying stream reaches likely affected by the presence of CECs.
      2. The adverse outcome pathway (AOP) framework provides insights into the mechanism of action of many CECs and has been applied successfully to assess impacts of CEC exposure in fish caged in Great Lakes tributaries.
      3. Molecular approaches, including metabolomics and transcriptomics are becoming increasingly powerful bioeffects surveillance tools to predict adverse effects at higher levels of biological organization. These tools also provide opportunities for non-lethal sampling of tissues (i.e., skin mucus swabs).
      4. The combined use of chemical monitoring and high-throughput in vitro toxicity databases (e.g., ToxCast) can be effective for identifying potential hazards associated with CECs in the Great Lakes and prioritizing specific contaminants, sites or biological endpoints for follow-up investigations. Computational tools that efficiently implement these approaches for large data sets with many samples covering large geographic regions are being applied and refined for use by resource managers.
      5. Complex mixtures of CECs have the potential to impact reproductive fitness at environmental concentrations. Effects of these CEC mixtures are complex and may not readily be extrapolated from the effects of individual constituents of the mixtures.
      6. CECs in Great Lakes tributaries are transferred through food webs from aquatic to terrestrial organisms, as was demonstrated by tissue analysis of tree swallows largely feeding on aquatic invertebrates.
      7. Resistance of invasive Great Lakes sea lamprey to a commonly used lampricide does not appear to correlate with historical exposures.
      8. Multiple, independent lines of evidence, from analytical chemistry and bioeffects monitoring, to studies of resident wildlife and laboratory exposure experiments converge in identifying priority areas for further monitoring, research, and management actions as a result of CEC presence and observed biological effects.

      The engaging discussions that occurred among presenters and the audience frequently spilled from the session auditorium to the coffee breaks and poster socials, highlighting the intense interest within the community for understanding and addressing the impacts of CECs on the Great Lakes. Clearly, there is a need for further investigations and integration of the current findings into a larger framework for modeling the occurrence and biological effects of CECs in the Great Lakes. A key conclusion the audience took from this spotlight session was that much progress has been made to assess the threat caused by CECs on wildlife in the Great Lakes and that natural resource management tools to prioritize sites for further study or bioremediation are on the horizon. 

      Authors’ contact information: hschoenfuss@stcloudstate.edu, srcorsi@usgs.gov,ekman.drew@epa.gov and villeneuve.dan@epa.gov

  • New Approaches to Long-standing Challenges: Issues and Solutions Associated with TRV Development
    Mark S. Johnson, U.S. Army Public Health Center, Aberdeen Proving Ground; Nancy Judd, Windward Environmental; and David D. Mayfield, Gradient Corporation

    • Developing toxicology benchmarks for applications in risk assessment has been an evolving challenge for decades. Benchmarks are developed and applied to a variety of media (tissue, dietary constituents, soil). Incomplete toxicity data sets, variation in response, differences in study conduct and statistical error all contribute to variations in interpretation. For example, differences between species might be due to variation in toxicokinetics driven by environmentally weathered forms and differences in gastrointestinal physiologies. Physiological differences within a vertebrate class can drastically affect absorption; hence, can add substantially to a reduction in predictive capabilities of risk assessments.

      These issues are more complicated for metals, which may be naturally occurring and, in some cases, are essential nutrients. Focused use of negative data has yet to be included and valued in benchmark development. In this session, perspectives and progress examples were provided from regulatory, industry and risk assessment experts from the United States, Europe and Canada to further the science used in the development of toxicity-based benchmarks used in risk assessment.

      The chairs of this session (Johnson, Mayfield and Judd) began with a brief history of toxicity reference value (TRV) development for terrestrial wildlife and highlighted some wicked problems associated with past experience. Johnson highlighted progress in the use of dose-response curves in TRV derivation, and noted that the concept of “systemic review” actually began with ecological risk assessment nearly 15 years ago with the Eco Soil Screening Level project standard operating procedures for documentation of literature reviews and data extraction. He noted progress in combining dose-response curves for a given endpoint for several species, taking species sensitivity distributions further.  He also noted many sources for variation and areas for further research and improvement.

      Mark Sprenger provided some concerns with a comprehensive and clear understanding of the question – understanding screening vs. remedial values and the use of consistent sources and the way the science is presented.

      Dale Hoff provided updates on the ECOTOX database that includes a mechanism to plot data on curves in the search of dose-response thresholds. The development of mechanisms for seamless extraction of the data that are available is continuously under improvement. Currently, ECOTOX has data for more than 11,000 chemicals, 46,000 publications, including more than 12,000 species. The release of the revised beta version is expected soon.  This revised version will allow for estimates and confidence limits of toxicity data in a dose response framework using the Toxicity Relationship Analysis Program (TRAP).

      Brad Sample provided a site-specific example where a probabilistic method that integrated exposure analysis with dose-response toxicity information for methylmercury data was used to refine risk estimates for site-relevant bird species at a former mining site.

      Berit Bergquist provided a review of dose-response modeling comparing and contrasting TRAP and benchmark dose models where the latter requires estimates of variation in response within each treatment and the former does not.

      Koen Oorts presented metal soil concentration benchmark calculator for plants, invertebrates and microorganisms to derive Predicted No-Effect Concentrations (PNECs) for use the European Union. This model considers bioavailability of metal form and environmental background in PNEC derivation.

      Ute Pott discussed the issues of variation experienced at various contaminated sites for TRVs used for the same substance and the need to develop consistency. She provided progress towards a TRV scoring system that was developed and used to establish a default set of TRVs based on objective criteria.

      David DeForest discussed the importance of understanding the relative influence of diet-borne exposures relative to those substances dissolved in water when assessing risk to aquatic organisms such as fish.  He provided compelling evidence that implied chemical physical properties of the substance or metal form are important in understanding the most relevant exposure pathway.

      Together, these presentations provided a comprehensive understanding of advances in understanding toxicity relationships for metals (and other substances) and recognized specific areas for improvement. That TRVs are still being developed specific to each application remains an issue from at least a screening perspective, and calls for the development of a single, coordinated effort remains a need internationally.

      Authors’ contact information: mark.s.johnson.civ@mail.mil, NancyJ@windwardenv.com and dmayfield@gradientcorp.com

  • Microplastics in the Aquatic Environment: Fate and Effects (WATCH RECORDINGS)
    Kay T. Ho, Robert M. Burgess, U.S. EPA, Narragansett, RI and Susan B. Kane Driscoll, Exponent, Maynard, MA

    • Microplastics in the Aquatic Environment-Fate and EffectsWhile the presence of microplastics in sediments, waters and organisms have generally been documented, questions of fate and effects remain unanswered. This session highlighted some of the innovative research and concerns surrounding techniques and approaches used to measure microplastics and determine their fate and effects. The session started with two presentations on Charleston Harbor in the southeastern United States. Barbara Beckingham, College of Charleston, focused on the wastewater treatment plants (WWTPs) that surrounded the harbor.  Beckingham reported that WWTPs generally removed greater than 90% of microplastics from their influents and their efficiency was related to the design of the plant with clarifiers and primary screen sizes being important factors. The second presentation by Rachel Leads, College of Charleston, highlighted the large percentage of suspected black tire wear particles in the microplastics counts found in Charleston Harbor. Peter Lenaker, US Geological Survey, showed the importance of sampling throughout the water column when quantifying microplastics. The data showed that sampling either near the top or the bottom of the water column would bias the total count, as well as the types of particles that were recovered.  

      The next two speakers reported on the effects of micro- and nanoplastics on bivalves. Caitlin Wessel, Dauphin Island Sea Labs, showed that the conditioning index of oysters decreased after exposure to microparticles of polyethylene and polystyrene. Evan Ward, University of Connecticut, demonstrated via innovative video techniques that bivalves can distinguish between particles types and sizes and that when nanoparticles are incorporated into naturally-occurring marine snow, their uptake increases. Moving from bivalves to beverages, Mary Kosuth, University of Minnesota, examined 12 brands of beer, 12 brands of table salt and 159 globally sourced tap waters. Kosuth found anthropogenic particles in the salt and beer in over 98% of the brands tested with fibers being the most typical particle. Of the waters tested, 83% contained particles, mostly fibers. Chemical characterization will be performed on particles to confirm their synthetic nature. Katherine Martin, Texas A&M University, discussed the experimental design to quantify the riverine load of microplastics in the Mississippi River. In the final presentation of the session, Kristin Connors, Proctor and Gamble, outlined some critical principles to move the science of microplastics forward, including use of appropriate controls, characterizing particles accurately and with enough detail, standardizing methods and testing environmentally-relevant concentrations. In addition to the platform presentations, there were 11 posters covering a wide range of topics from the effects of nanoplastics on zebrafish to the degradation of biodegradable plastics in a salt marsh habitat. Themes repeated throughout the session were the need for the use of appropriate controls and blanks, as well as good laboratory practices to prevent inadvertent contamination of samples. Sessions on microplastic research are planned for the SETAC Europe 28th Annual Meeting this spring in Rome.

      Authors’ contact information: Ho.Kay@epa.gov, Burgess.Robert@epa.gov and sdriscoll@exponent.com

  • More Data Is Not Always Better – Using Weight-of-Evidence Approaches in Environmental Risk Characterization
    Mark S. Johnson, U.S. Army Public Health Center, Aberdeen Proving Ground; Mary Sorensen, Ramboll Environ Corp; John Toll, Windward Environmental; and Susan Turnblom, Oregon Department of Environmental Quality

    • Characterizing various measures of toxicity and exposure into a risk matrix is rarely straightforward. Often, stakeholders can all agree on the integrity of the data, but rarely is there agreement on what the data mean in a risk assessment context. Toxicity data can vary depending on methodology, species and interlaboratory differences. Field data may vary depending upon site-specific criteria. All forms risk the probability of false positive and negative outcomes. This session was devoted to the exploration of new methods developed to interpret similar and disparate data streams; to help ascertain false negative and positive results from what may be informative. Presentations covered specific examples of ecological and human health concerns where environmental exposures were issues of study and provided novel approaches in harmonizing assessment measures into meaningful characterizations of risk for decision making.

      Glenn Suter started off the session describing the elements of the U.S. Environmental Protection Agency’s (USEPA) Weight-of-Evidence (WoE) guidance document for ecological risk assessments. He provided details on a 3-step process in gathering, evaluating, and weighting evidence and listed 13 systematic properties of relevance.

      John Toll briefed the audience on the initial utility of using probabilistic or Bayesian methods on a case study regarding PCBs in sediment and risk associated with exposure to a winter flounder population. In this example, he used Monte Carlo simulations to determine whether or not to collect additional data for risk management decisions.

      Jill Hedgecock investigated the influence of metals in sediment and groundwater seeps to bivalves in the field and showed how sediment linear regression analysis was more reliable than seep metal regressions in helping to predict bivalve metal body burdens.

      Steve Bay from the Southern California Coastal Water Program showed how they incorporated the USEPA WoE guidance on the sediment triad approach, whereby they gave highest weight on benthic macroinvertebrate data. They got expert and stakeholder agreement beforehand on how to weigh the results and showed data for San Diego up to San Francisco bay areas. They used habitat characteristics to help explain differences in the triad data and found that often toxicity and sediment chemistry data were not correlated.

      Mark Johnson demonstrated a process in the development of an occupational exposure level (OEL) to trichloroethylene (TCE) from a multitude of toxicity data that were variable. He used a process initially developed to prioritize toxicity data for Toxicity Reference Values (Eco Soil Screening Level, Standard Operating Procedure No. 3) to calculate weights for critical studies to help use negative toxicity data to discriminate false positive findings and to search for patterns in the data.  Although this process in on-going, patterns emerged for a provisional OEL for TCE in the range of 0.06 ppm.

      Lyle Burgoon presented how the Bayesian Inference for Substance and Chemical Toxicity (BISCT) model, which is a network used to create probabilistic likelihoods of an adverse outcome occurring. The weight of evidence function is built into this model. He demonstrated the approach for estrogen endocrine disruptors.

      Peter Dornbos discussed inter-individual variation within the human population and mouse strains and how it can impact immune responses to low doses of 2, 3, 7, 8-Tetrachlorodibenzodioxin. The weight of evidence reviewed indicated that the National Research Council’s hypothesis that the low-dose region of the dose-response relationships would be linear for noncancer endpoints, such as immunosuppression, does not apply to all dose-response relationships. He identified several candidate genes with the potential to affect individual susceptibility to TCDD.

      Susan Turnblom shared multiple lines of evidence evaluated to determine an arsenic relative bioavailability of 10 percent at a site in Oregon. Sequential soil extraction results, Relative Bioavailability Leaching Procedure results, and arsenic speciation and mineralogy by electron microprobe analysis all supported this conclusion. This had a significant impact on the cleanup needed at the site.

      Together these presentations linked various ways to evaluate, assess and integrate disparate data streams in providing more effective means to characterize risk at various levels and assisted in increasing the understanding of objectively identifying means of error (e.g., false negative and false positive results). Extending this theme into a more focused workshop may be a useful way to develop more effective science-based tools for risk assessment purposes.

      Authors’ contact information: mark.s.johnson.civ@mail.mil, MSorensen@environcorp.com, JohnT@windwardenv.com and Susan.Turnblom@state.or.us


SETAC Minneapolis Abstract Book

SETAC Minneapolis Abstract Book

Download a copy of the SETAC Minneapolis abstract book.


 


Sacramento, California

Looking Ahead

Save the date for the SETAC North America 39th Annual Meeting, which will be held from 4–8 November 2018 in Sacramento, California. Session submission is now open.


 

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