Summaries Published in the April 2018 Issue
Jone Corrales, Baylor University, and Marlo Sellin Jeffries and Leah Thornton, Texas Tech University
Adequate immunocompetence enables individuals to maintain good health in the natural environment by avoiding infection and disease. Environmental perturbations, such as exposures to anthropogenic contaminants, are of alarming concern because they can impair immune responses, potentially putting fish and wildlife at risk of disease, death and population decline. Furthermore, in an era of rapid climate change, the impacts of environmental stressors (e.g.,altered temperatures, increases in hypoxia events, harmful algal blooms and ocean acidification) on immunocompetence and disease survival are not clearly understood. It is therefore critical that the potential immunotoxic effects of these chemicals and environmental stressors be investigated.
The goal of the session was to include presentations that detailed the effects of environmentally relevant contaminants on various aspects of immunity at all levels of biological organization, from the cellular level to the population level. Presentations that shared novel methods for assessing immune function, particularly in wild-caught organisms, were encouraged, as were those that highlighted challenges associated with assessing stressor-induced alterations in immunity.
During the SETAC North America 38th Annual Meeting in Minneapolis, Minnesota, we held the first platform session solely focused on immunotoxicology. We had presenters from Canada, Japan and the United States, including Van Ortega from the University of Alberta, Kei Nakayama from Ehime University, Maria Rodgers from the University of Southern Mississippi, Leah Thornton from Texas Christian University/University of North Texas, Christopher Martyniuk from the University of Florida, Tawnya Cary from Beloit College, Jason Hoverman from Purdue University and the well anticipated presentation by Charlie Rice from Clemson University, a highly recognized fish immunotoxicologist in the United States. Interestingly, the mean number of attendees increased from 49 to 63 after the coffee break with an overall mean of 56. The number of attendees for the last presentation was 75.
The presentations comprised a broad-range of projects, which represented the complexity and critical function of the immune system. Briefly, Ortega showed how nanoparticles can disrupt immune function, an area scarcely investigated, while Nakayama discussed the importance of selecting a suitable host-pathogen model for immunotoxicity studies by presenting advantages and disadvantages of different studies using various host-pathogen combinations. Presentations by Martyniuk and Thornton showed the potential for cross-talk between the endocrine and immune systems, suggesting that the immune system may be a potential target for disruption following exposures to compounds with known or suspected hormonal activity. Additionally, Cary demonstrated that the immune system of developing organisms may be more sensitive to disruption by chemicals than that of adults, suggesting that there is a need to understand how contaminant exposure may alter not only immune system function, but also immune system development. Hoverman emphasized that understanding the implications of ecology and evolution on disease resistance are essential to better recognize toxicity effects of contaminants and showed that the immune system is altered due to chemical exposure at the population level in ecologically important species. Rodgers presented the same outcome at the organismal level in commercially important species. The session ended with a comprehensive presentation by Rice, who offered an overview of the past, present and possible future of aquatic and wildlife environmental immunotoxicology. Rice ended his talk with encouraging words for the next generation of immunotoxicologist on the advancement of the field and proposed the development an adverse outcome pathway (AOP) for immune function impairment due to chemical exposure.
Conclusions From the Session
- Both presenters and attendees indicated a need to put environmental immunotoxicology as a discipline in the spotlight.
- Immune function and immune response related pathways are consistently identified as being impacted by a variety of stressors in -omics (e.g., transcriptomics, proteomics) studies.
- Immunologists by training (especially those in veterinary medicine) and toxicologists need to come together and determine appropriate experimental approaches and practices (e.g., study designs, “host-pathogen” models, immune function endpoints). Ultimately, there is a need to establish the foundation to develop standardized guidelines in environmental immunotoxicology, which do not currently exist.
- There is a need to develop an adverse outcome pathway (AOP) for immunotoxic effects in a way that is useful in environmental risk assessment. To date, molecular initiating events and adverse outcomes have not been defined for immunotoxic effects. Developing the AOP will offer a consistent structure and terminology for organizing our understanding of immunotoxicology while it will also facilitate application and integration of diverse information, which will in turn help identify additional research needs.
As a result of the productive conversations in Minneapolis, we intend to hold another session focused on immunotoxicology at the SETAC North America 39th Annual Meeting in Sacramento, California, pending the planning committee’s approval. In Sacramento, we plan to continue the conversation on the conclusions outlined above. In addition, we plan to hold a formal group discussion the same day of the presentations to discuss details on the need to develop an AOP for immunotoxic effects. Ultimately, we hope to bring enough evidence for the relevance of immunotoxicology as an additional endpoint relevant to environmental risk assessment. As session chairs, we recognize that the presenters in Minneapolis were from academia, and we want to extend a special invitation to present for those in government and business.
Finally, the session will support the One Health concept, which recognizes that the health of humans, animals and ecosystems are interconnected and is now endorsed by the European Commission, the US Centers for Disease Control and Prevention, World Health Organization, Food and Agriculture Organization of the United Nations and World Organization for Animal Health, among others.
Cecilia Mancini and William Reese, AECOM
Unique features of remediation sites and programs necessitate site-specific, sustainable strategies to satisfy remedial objectives. Technological advancements, and a better understanding of the dynamic physical, chemical and biological processes associated with contaminated media, continue to provide opportunities for innovative, sustainable designs and associated remediation and monitoring techniques. This session showcased a range of examples of how innovative remedial tools continue to evolve to address unique challenges associated with monitoring the effectiveness of remediation and restoration programs.
The session covered a variety of tools intended to address equally diverse challenges of remediation and monitoring for numerous constituents in a variety of sites and ecosystems. Ecosystems investigated included wetlands of Canada, Colorado streams and marine systems of Pearl Harbor. Constituents of interest were also diverse, including mercury and copper, PCBs and PAHs, salt and organic micro contaminants.
The key points for the eight presentations are summarized below:
- A successful case study on how purposeful remedial objectives of a complex mercury site can integrate restoration and remediation and address stakeholder needs was presented by Ceil Mancini, AECOM. The design strikes a balance between regulatory requirements and the concerns of local stakeholders.
- A case study on the use of drone-based imagery to communicate with stakeholders was given by Bill Reese, AECOM. Drone imagery is being used successfully to communicate to a complex stakeholder team. This tool provides an up-to-date bird’s-eye view of remediation and portions of expansive sites that would otherwise be inaccessible.
- Redevelopment of existing field technologies was discussed by Jessica Carilli, SPAWAR Systems Center. A modification to existing passive sampling devices is shown to enhance cost-effective deployment and retrieval in a spatially expansive, long-term monitoring program at Pearl Harbor.
- A variety of chemical and biological indicators are monitored in the Ottawa River to test the effectiveness of a sediment removal remedy as described by Roger Yeardley, USEPA. Consideration of biotic endpoints, such as tissue and DNA damage, can provide additional useful alternative monitoring data, particularly in a weight-of-evidence evaluation.
- Phytoextraction using Phragmites australis has proven very effective in the remediation of salt-impacted soils at a cement kiln dust (CKD) landfill in Bath, Ontario, as summarized by Barbara Zeeb, Royal Military College. However, the use of invasive species, such as Phragmites australis, comes with unintended consequences. In this case study, the use of native recretohalophytes was shown to be more sustainable and enhancing of post-remediation restoration when compared to the proven use of the invasive species.
- The case study of a mining-impacted waterway, North Fork of Clear Creek in Colorado, contributes to a database critically lacking in real-time data. As presented by Jill Murphy, Colorado School of Mines, the data were used in demonstrating the response of the waterway to remediation. While the data suggests that the system is responding to the remedy, on-going migration pathways may continue to serve as latent metal contamination sources.
- Soil amendments continue to gain favor as an effective treatment option. In this case study, Matthew Wilfong, Towson University, coupled the results of field data collection with laboratory testing to show that commercially available soil amendments can enhance the export of copper in the treatment of copper roof runoff.
- New TAML/peroxide activators represent a potential breakthrough in water treatment of organic micropollutants as demonstrated in this platform given by Genoa Warner, Carnegie Mellon University. This new form of activators features sulfonamide-containing ligands composed of biochemically common elements.
The collective findings of the session demonstrate the importance of continued innovation toward sustainable remedial designs and associated monitoring techniques. Dissemination of the learnings from these case studies and on-going work will further advance the level of acceptance of sustainable remedial approaches.
Frances Nilsen and Christina Baghdikian, USEPA; Nil Basu, McGill University; and Tom Augspurger, U.S. Fish and Wildlife
Overview of Session
“One Health” is an organizational framework encouraging interdisciplinary collaborations in education, research, clinical practice, policy and communication stemming from the recognition that the health of people, other animals and the environment are linked. One Health partnerships are growing internationally, mainly emphasizing prevention of infectious zoonotic diseases (those that can be passed between animals and humans), but the environmental quality connections to human and animal health are often less developed in One Health collaborations.
Realizing that SETAC’s science can guide the environmental quality component of One Health partnerships, we hosted a third session of overviews, case studies and perspectives on One Health at the SETAC North America 38th Annual Meeting last fall in Minneapolis, MN.
This year’s session included presentations from the U.S. Environmental Protection Agency, Boston University School of Public Health, the University of Louisville, Breveja Environmental Consulting, the Medical University of South Carolina and the National Institute of Standards and Technology. The diverse group of presenters provided examples of the One Health framework in action, highlighting areas that can be expanded within SETAC, and making suggestions for future integration of One Health across disciplines and sectors.
- The necessity in evaluating systems-wide exposures to environmental contaminants. Measurements in water, sediment and fish were detailed and implicated to have a direct link to the Grand Portage Indian Reservation of the Minnesota Chippewa that utilize those resources (Seth Moore, Grand Portage Band of Lake Superior Chippewa). The health of fish is directly related to the health of their human consumers, indicated by the fish used as biological models and indicators of human exposure from New Bedford Harbor, MA (Kathyrn Crawford, Boston University School of Public Health). The changing concentration of contaminants in fish as a result of policy changes also has a direct effect on human health and warrants the integration of many disciples under the One Health paradigm (Paul Ringold, USEPA).
- The use of sentinel species for elevated or pseudo-occupational exposure in humans to investigate pressing human health concerns. Great whale species have provided unparalleled surrogates for carcinogenesis related to hexavalent chromium exposure (John Wise, Wise Laboratory of Environmental and Genetic Toxicology), and reptilian species have emerged as models for dietary mercury exposure research (Frances Nilsen, National Institute of Standards and Technology).
- The utility of frameworks in the adoption of the One Health paradigm across many fields of research, despite the complexity associated with systems-based approaches. The EcoHealth Driving Force-Pressure-State-Impact-Response (DPSIR) framework was introduced and provided for structural simplicity to address complex problems (William Fisher, USEPA), as well as the discussion of gaps in policy between health and conservation that would better serve systems-based approaches (Alonso Aguirre, George Mason University).
- The essential need for a One Health approach in global pollutant knowledge dissemination, specifically related to mercury and the Minamata Convention as a holistic approach, is needed to effectively reduce risk (Bruce Vigon, Breveja Environmental Consulting LLC).
The One Health movement is gaining traction in our diverse society as SETAC members have a natural inclination to address complex problems in an interdisciplinary way. Many of you are performing or applying lessons from interesting research, which is likely to fall into the One Health framework. We have a few One Health activities in the works for the 2018 SETAC North American annual meeting, to introduce what the framework is, how you fit and the benefits of working within the framework.
We encourage everyone to participate, so make sure to look for all of the One Health activities at SETAC in Sacramento!
Tara Sabo-Attwood and Joseph H. Bisesi Jr, University of Florida, and P. Lee Ferguson, Duke University
Our understanding of environmental pollutant sources, fate and impacts in developing countries is limited despite the recognized association between chemical exposure and adverse health outcomes. Research into the fate and effects of pollutants in the developing world are challenged by social, economic, political, and logistical factors and obstacles. In addition, identifying components of chemical mixtures in surface and groundwater in developing nations is difficult due to the lack of available information about consumer and industrial chemical use. It is likely that mixtures of environmental pollutants in less industrialized nations are quite distinct from those typical of the developed world due to differences in use patterns, treatment technologies or disposal routes.
The purpose of this session was to highlight the current state-of-the-art in research addressing ecotoxicology and environmental health of the developing world, particularly with respect to chemical contamination. In particular, the session showcased work that takes an integrated approach to exploring pollutant occurrence through varied detection methodologies, human and ecological exposure, toxicological effects, and interactions of chemical pollutants with microbial pathogens in air, water and soil within the developing world.
The session was well attended, and it featured lively and interactive discussion led by the speakers who showcased work that spanned several countries.
The key points for the presentations included:
- Bryan Brooks, Baylor University, opened the session by presenting results of the Global Horizon Scanning Project joint workshops with SETAC Africa, Europe, Latin America, Asia-Pacific and North America, which served to define research needs that will advance our understanding of how a range of stressors impact environmental quality in different geographic regions. Themes that emerged included emerging contaminants in water due to agricultural and urban activities and the potential impacts on fish populations.
- Daniel D. Snow, University of Nebraska, presented occurrence and potential ecotoxicological impacts of legacy pesticides, including DDT and metabolites, HCH, heptachlor and endosulfan in riverine environments of Kazakhstan and Central and Southeast Asia. Detection of these compounds in sites with no historical local pesticide usage suggested contamination due to atmospheric deposition. Select compounds were also found in fish species that are a component of the local diet.
- Luisa Angeles, State University of New York-Buffalo, presented on behalf of Diana Aga on the occurrence of brominated flame retardants in fish, air and sediments in the Philippines. It was clear that PBDE compounds were important contaminants in environmental samples collected in this region and that levels were similar to those measured in other urbanized areas of the world.
- A universal non-selective passive sampling device (nsPSD) developed by Damian Shea from North Carolina State University was described as a novel approach for measuring bioavailable pesticides in the Red River watershed of China and Vietnam. This methodology was developed to circumvent current passive sampling methods that are limited to hydrophobic chemicals. This technique was particularly suited to application in analysis of organic pollutants in the waters of the developing world as the approach required little on-site instrumentation or technical equipment, and it provided a quantitative method to estimate exposure of compounds such as pyrethroid insecticides in water.
- Tara Sabo-Attwood from the University of Florida described a major challenge of assessing chemical contaminant occurrence and exposure in Haitian waters, which have limited information about chemical use. This makes targeted chemical analysis of surface and groundwater samples difficult. She presented a non-targeted mass spectrometry method developed by collaborator P. Lee Ferguson from Duke University, which was utilized to generate chemical fingerprints from 13 water samples from wells and surface water samples in Haiti. Using this approach, they were able to identify several industrial, pharmaceutical and natural chemical contaminants. Additionally, the group is currently investigating the impact such chemicals have on notable waterborne pathogens in Haiti, such as toxigenic Vibrio cholera, that have a major public health impact on the country.
- Jonathan Ali from the University of Nebraska-Omaha presented a case study using native sentinel organisms (in this case the pencil catfish) to conduct biomonitoring studies in natural Chilean waters. Specifically, transcriptome annotation was accomplished to perform gene-expression-based monitoring of biological responses downstream of pollutant sources along the Choapa river. This strategy was successful for observing endocrine disruption effects in fish exposed to runoff from agricultural lands. The presentation illustrated several unique challenges of developing biomonitoring tools in a remote setting, like Chile. It also served to identify opportunities to improve approaches to ecotoxicology in the developing world by leveraging the advantages of local species as pollution sentinels.
- There are significant challenges associated with establishing advanced water quality testing in developing countries, including access to equipment, developing a client base, recovering costs of testing and finding a liaison with government agencies to achieve laboratory certification. Joseph Bisesi from the University of Florida showcased an approach to setting up a sustainable certified water testing laboratory in Haiti. Working with a group of students in a small-business consulting course called “GatorNest” at the UF Entrepreneurship and Innovation Center, his team tackled cost analysis, logistical issues and government certification with the goal of transitioning the lab to a Haitian-run business.
Conclusions From the Session
The session highlighted challenges and approaches to pollution assessment in developing countries, with a focus on aquatic toxicology, environmental health and environmental chemistry. In particular, much discussion centered on the unique challenges inherent in conducting technically demanding ecotoxicology and analytical chemistry research in field settings far from laboratory facilities. The session ended with a discussion period where several key points were made:
- It was recognized that research in the area of ecotoxicology and environmental health of the developing world must engage local partners fully in order to be successful and to realize benefits. Additionally, the significance of pollution-mediated disease in humans and wildlife needs better recognition and funding from international development agencies and stakeholders.
- Modified sampling methods, such as universal non-selective passive sampling devices, are effective in capturing chemicals with varied properties (e.g., hydrophilic compounds).
- Due to the limited knowledge of industrial and consumer product use, fate and transport, analytical detection methods using contemporary non-targeted mass spectrometry approaches afford information on the chemical “soup” present in water sources.
- The biological impact of chemicals on water-borne infectious agents that are of public health importance in developing countries have been understudied. Additionally, exposure of organisms to chemical pollutants may increase host susceptibility to pathogenic infections through altered immune status.
Ronald T. Checkai, Mark S. Johnson and Doris A. Anders, U.S. Army Corps of Engineers
Military entities serve a unique function in national security. Research, development, production and use, and demilitarization of weapon systems and platforms can result in environmental releases of unique substances such as explosives, pyrotechnics and propellants, as well as heavy metals. Many military training ranges require large areas that, except for these activities, utilize restrictions from other types of human activity and can result in unique habitats and communities. This session was devoted to characterization, toxicology and new research developed in this area to help sustain military operations and natural resources. The session was well attended and contained more than seven presentations and 10 posters. Some of the topics presented are highlighted as follows:
- Dom DiToro, University of Deleware, provided some computational approaches for estimating environmental degradation for some high-nitrogen compounds in soil matrices.
- Matt Berens, University of Minnesota, addressed how soil mineral constituents can affect the fate and transport of nitroaromatic substances in soil, sediment and groundwater.
- Gui Lotufo, U.S. Army Engineer Research and Development Center (ERDC) provided issues associated with understanding the toxicity of new insensitive munition formulation for an aquatic amphipod (Hyalella azteca).
- Lyle Burgoon, ERDC, provided his ideas on the development of an acceptable daily human dose for two explosives, RDX and TNT, using toxicogenomic information.
- Kust Gust, ERDC, presented how using toxicogenomic information can help to better understand potential pathways to explain the greater-than additive toxicity associated with new insensitive munition formulation constituents following environmental breakdown (e.g., photolysis) in aquatic systems for fathead minnow. Al Kennedy, ERDC, also provided more details regarding the stability and toxicity of a photolytic breakdown product of nitroguanidine.
- David Kuo, City University of Hong Kong, described how nitrocellulose can bind other energetics that that remain from some fired propellant residues, hindering leaching potential to groundwater.
Posters included new research into the science of contract transfer of chemical agent from plants, new methods to better analyze for and new bioaccumulation information for perfluoroakyl substances, bioavailability of polyaromatic hydrocarbons in soil to humans, risk assessment examples at a Canadian military test site and new methods for assessing groundwater discharge in estuarine environments.
Conclusions from the session included discovery of a photolytic breakdown product from nitroquanidine that is more toxic than parent and could be more persistent. This could present some issues with wastewater discharge from manufacturing facilities and for range sustainment.
The session also provided some examples of sophisticated tools that can be used to help tease apart potential mechanisms for toxicity that may enable greater precision when extrapolating dose–response relationship between species.
Author’s contact information: Mark.S.Johnson.email@example.com
Summaries Published in the March 2018 Issue
Michael Carvan, University of Wisconsin-Milwaukee; Cheryl Murphy and Lori Ivan, Michigan State University
Many toxicants have sublethal effects on organisms that may be relevant at higher levels of organization (e.g., population and community levels). Behavior is one means of analyzing the sublethal effects of toxicants on organisms as behavior integrates the physiological response of an organism to external stimuli. However, many behavior assays used in ecotoxicology cannot be used to assess an individual’s fitness within an ecological context and therefore cannot be used to determine how these subtle changes in behavior may impact populations or communities. Adverse outcome pathways (AOPs) are one means of connecting impacts of toxicants at low levels of organization (molecular) to higher levels of organization (individual, population, community).
Our session explored the methods of analyzing ecologically relevant behavior, incorporating that behavior into computational models and analyzing sublethal impacts at higher levels of organization, all within the construction of adverse outcome pathway (AOP) framework. The presentations included a variety of study organisms, chemicals and relevant behaviors. The sessions discussed three main topic areas including ecologically relevant behaviors, models that use these data to forecast effects to higher levels of organization, and the construction of AOPs.
- In order to extrapolate information gleaned from behavior to higher levels of organization, appropriate behavioral assays need to be constructed. Lauren Gillespie, Central Community College, presented an experiment to test hormone levels and aggression in the mangrove killifish. Her experiments were designed with a pre- and post-test analysis using a mirror test. Results showed that fish exposed to 2,4-Dichlorophenol exhibited decreased aggression. Further, she found that larger fish exhibited higher rates of aggression, although the pattern of reduced aggression because of exposure held true for larger-sized fish. Elizabeth Peterson, Colorado State University, examined the influence of lead on multiple Drosophila strains to determine how lead and genetics impact reproductive behavior, including copulation time, copulation latency and fecundity. Lead was found to reduce fecundity across all strains analyzed, but patterns varied across strains for copulation time and copulation latency (the time between matings). These findings point to the importance of considering intraspecific variation in genetic and phenotype variability when assessing impacts of contaminants on individuals. Irvin Huang, Stony Brook University, developed a larval zebrafish behavioral assay to screen multiple pharmaceuticals, which are often found at environmental concentrations below that of lethality but could impact survival via behavioral changes. Zebrafish were tested for a variety of behavioral endpoints, including the visual motor response (VMR), acoustic and visual startle response and stimulus habituation. Of the currently screened chemicals, VMR was the most sensitive with a decrease in swimming activity. The authors will incorporate these findings into behavioral investigations that include prey capture and learning. Finally, Michael Simonich, Oregon State University, and his colleagues examined the impacts of 61 flame retardants on zebrafish survival and development and on neurobehavior using two high-throughput photomotor response assays. He showed that similar chemical structures among flame retardants produced similar morphological and behavioral changes in zebrafish but that groups of flame retardants could produce different behavioral changes – specifically, changes in activity levels in larval fishes. Future directions of that research team was to examine more complex behaviors in fish 90 days post fertilization that were exposed during fertilization. These complex behaviors included anxiety, social behavior and fear response behaviors.
- With the appropriate collection of ecologically relevant behavioral assays, it is possible to use models to assess how behaviors compared at the level of the individual scale to population levels. To that end, two models that use assay information to explore impacts on cohort survival and larval growth were discussed. First, Brandon Armstrong, Michigan Department of Environmental Quality, used an individual-based model to explore how previously analyzed sublethal behavioral effects of methylmercury on yellow perch larvae affected cohort survival in a simulated Lake Michigan environment. The model revealed that subtle alterations in larval fish behavior, placed in a modeled environment with predators and prey types, can affect cohort survival by decreasing the survival of modeled cohorts by up to 88% over simulations without methylmercury (MeHg) effects on swimming speed. Second, Lori Ivan, Michigan State University, presented a generalized individual-based model that can incorporate sublethal effects of contaminants on various larval fish species. The model will allow researchers to determine how behavior data collected at the individual level can affect higher levels of organizations within an ecological context over a range of species and contaminant types. She showed an example of how to apply this model using fathead minnows, MeHg effects and PCB-126 on swimming speed modeled in a typical Michigan inland lake.
- Finally, a goal of developing AOPs was discussed by both Michael Carvan, University of Wisconsin-Milwaukee, and Evan Gallagher, University of Washington. Carvan detailed ongoing work to develop AOPs that link molecular initiating events to population-level outcomes in three fish species for two toxicants, MeHg and PCB-126. His research is currently combining effects on larval fish RNA sequencing of larval fish brains and individual behavioral assays for swimming speed and foraging success to inform population models. Meanwhile, Gallagher developed a neurobehavioral injury adverse outcome pathway for environmental neurotoxins by examining Coho salmon and zebrafish response to olfactory disruption.
The overall conclusion of the session was a call for researchers to develop and use assays to test ecologically relevant behaviors to aid in model development that also fit in the AOP framework. The session also highlighted the variety of behaviors that could have important implications on populations, as well as the importance of considering species outside model species when considering the effects of contaminants as species (and indeed within species populations) can vary in their response to the same level of contaminant. Finally, it was pointed out that exposure during development may be important in later life of organisms and that more emphasis needs to be placed on this type of research, especially as it relates to estimating adverse outcomes at higher levels of organization.
Maikel Rosabal, University of Quebec in Montreal, and Christopher Cooper, International Zinc Association
Knowledge on the fate and effects of trace metals, specifically on the underlying mechanism governing bioavailability, bioaccumulation and toxicity of trace metals, is crucially needed to understand and predict metal effects in aquatic environments. Although some progress has been reported, there are still knowledge gaps to be addressed. To increase our knowledge on these issues, a platform and poster session titled “Fate and Effects of Metals: Mechanisms of Toxicity” was convened, where academic scientists, policy makers and risk assessors from different backgrounds (industry, private sector) were assembled. The session consisted of eight platform presentations and six posters.
The research presented in this session focused on biogeochemical parameters that affect mechanisms of metal uptake, understanding the mechanisms leading to biological or behavioral impairment, and (iii) metal toxicity model development with the aim of improving environmental regulation.
The chemistry of the aquatic environment has a significant effect on the toxicity of metals towards an organism. Therefore, there was a special emphasis on mechanisms by which biogeochemical parameters (chloride, pH, dissolved organic matter, etc.) influence the bioavailability and bioaccumulation of trace metals. For example, using an in vitro rainbow trout gut cell line, one platform presentation examined the effects of varying chloride concentrations (mimicking the levels found in aqueous environments) on the uptake and toxicity of copper and silver. In addition to this presentation, a poster from the same research team, also using a rainbow trout gut cell line, investigated trace metal mixture (including silver, copper, cadmium, and zinc) effects on metal uptake and toxicity. There was a presentation that investigated the influence of pH on uptake and bioaccumulation of zinc, and on major cation homoeostasis in an aquatic invertebrate that’s able to tolerate acid and metal-contaminated waters. In addition to these aqueous exposures, a more integrative study on freshwater snails developed a kinetic bioaccumulation model for uranium, considering not only the way in which geochemical variables (pH, dissolved organic matter, hardness) influence metal bioaccumulation but also how physiological parameters predict metal accumulation from dissolved and dietary phases. There was also an ongoing study that examined the different sensibility of juvenile snails chronically exposed to Ni-contaminated tap water from Miami and Vancouver cities with apparently similar chemical composition but distinct dissolved organic matter properties.
On a related topic, three posters focused on the effect of lake water quality on mercury production, of diet borne selenium exposure on arsenic accumulation in different fish tissues, and of metal pre-exposure on the survival response of zinc-exposed amphipods over time.
Once metals have been taken up, if critical levels are exceeded, detrimental biological and behavioral effects can be observed; but again, the mechanisms behind these effects are still being explored. There was a presentation that investigated the underlying mechanism of action through which chronic dietary selenomethionine exposure induces effects on the metabolism and the cardiovascular function in adult rainbow trout. A laboratory study on adult sea cucumber fish showed how acute copper waterborne exposure produces metabolism impairments in gut cells. Another presentation reported changes in emersion behavior of the mangrove rivulus that was associated with cellular alteration in gill cells when fish were exposed to waterborne copper and varying CO2 concentrations. A poster also examined how waterborne exposure of metal salt forms, including chloride, nitrates and sulfates, affected the swimming capability of Daphnia measured as an immobilization test. Finally, a poster presentation provided molecular evidence of the toxic effects on the stress response and innate immunity caused by in situ exposure of field-collected clams using transcriptomic profiles.
One of the ultimate goals for the understanding of mechanisms of toxicity is to better develop models whereby metal toxicity can be predicted and thresholds can be set up to protect the aquatic environment. Using juvenile rainbow trout, a study reported the development of experimental-based biotic ligand models for acute and chronic toxicity of waterborne copper, where the influence of pH, hardness and dissolved organic carbon on the metal toxicity was pertinently incorporated.
Conclusions From the Session
Overall, this session provided perspectives of the mechanisms of uptake, bioaccumulation and toxicity across metal classes, biological levels of organizations and different aquatic organisms. There are many biogeochemical parameters that have significant effects on the bioavailability and bioaccumulation of trace metals. It is important to understand these at the mechanistic level so to be able to understand effects and consequences at the organism level. Historically, one of the key indicators of metal toxicity was mortality, but it is clear that there are multitudes of sub-lethal chronic effects that can reduce or alter the performance of the individual. These will have knock on effects at the population and ecosystem level. All of these presentations highlighted the value of including such results in the development of realistic, reliable, science-based environmental risk assessments. However, there is still a need to continue these lines of research to ensure that regulations and thresholds that protect the environment are science-based, and SETAC is a great forum for linking the environmental science with the regulatory arena.
There were around 60 attendees in this session. The session was supported by the International Copper Association, the International Zinc Association and the Metals Interest Group.
Amila De Silva, Jane Kirk and Magali Houde, Environnent and Climate Change Canada
For the second year in a row, SETAC North America hosted a session that focused on contaminants in changing Arctic environments. Many scientists and local communities are presently trying to better understand the climate-induced changes occurring in Arctic regions in order to predict more accurately the future of these pristine environments. Changes in water temperature, precipitation patterns, water mass distribution, ice-cover, food web composition and structure, and economic development are examples of factors that can impact the bioaccumulation and biomagnification of contaminants. This session provided a forum to disseminate results from research on the transport, fate and effects of legacy and emerging contaminants in Arctic ecosystems currently experiencing climate-induced changes.
The eight talks and four posters in this session revolved around four broad themes:
- Spatial and temporal trends of a diverse suite of contaminants in the abiotic environment and in Arctic organisms
- Contaminant accumulation through food webs
- Biological impacts of chemicals in Arctic wildlife and northern populations
- The importance of including indigenous traditional knowledge and collaboration of local communities alongside scientific research
Presenters from academia and government included principal investigators, postdoctoral scientists and two graduate students.
Magali Houde, Environment and Climate Change Canada, kicked off the session with a talk on spatial and temporal trends of legacy and emerging contaminants in ringed seals from across the Canadian Arctic. This talk also featured community outreach work that is being carried out as part of this long-term project.
Carrie McDonough, Colorado School of Mines, contributed a talk on spatial trends in emerging contaminants used as flame retardants, organophosphate esters (OPEs), in Fram Strait deep waters and Canadian Arctic surface waters through passive and active sampling methods. Organophosphate esters were frequently detected in the dissolved phase in Canadian Arctic surface waters and in deep water masses of Fram Strait, with concentrations at least an order of magnitude above those of more traditional brominated flame retardants such as polybrominated diphenyl ethers (PBDEs). These results demonstrate that Arctic waters are already significantly affected by these poorly understood, widespread organic contaminants.
MSc student Tristan Smythe, Carleton University, presented temporal trends in brominated flame retardants (BFRs) and perfluorinated alkyl substances (PFASs) in beluga whales (Delphinapterus leucas) from three populations in the Canadian Arctic. He showed that BFRs in Hendrickson Island belugas increased gradually between 1982 to 2013, which is opposite to the trend observed in other Arctic animals such as Northern fulmar, thick-billed murres and polar bears. Smythe stressed the importance of continued monitoring in the context of climate change.
Adam Morris, Environment and Climate Change Canada, presented a talk on the effects of climate change on contaminant trends in marine, terrestrial and avian wildlife of the Canadian Arctic and showed that climate factors were related to concentrations of persistent organic pollutants (POPs) and total mercury in polar bears, thick-billed murre and caribou of Hudson Bay. Other factors, including precipitation, wind speed, the Arctic Oscillation, the North Atlantic Oscillation, and sea-ice breakup or freeze-up were also pertinent. Morris also presented a poster that focused on the methods developed for modeling the effects of climate change on contaminant temporal trends in Canadian Arctic wildlife.
Derek Muir, Environment and Climate Change Canada, presented a talk on temporal and geographic trends of PFASs in Arctic caribou and reindeer, representing an international coordination of contributions from Canada, Denmark, Greenland, Norway and Sweden. Novel results included increasing concentrations of perfluorobutanoic acid (PFBA) in Canadian caribou and higher perfluorooctanesulfonic acid (PFOS) in Greenland caribou that graze near airports and communities.
Ana Cabrerizo, Environment and Climate Change Canada, showed declining trends in polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in landlocked char from Canadian high Arctic lakes between 1990–2015 in five study lakes due to international regulations. One exception was West Lake on Melville Island, whose catchment has undergone climate induced permafrost degradation, releasing legacy POPs and resulting in increased levels in char. Cabrerizo also showed that the incorporation of climatic parameters, such as precipitation and the North Atlantic Oscillation, helped explain year-to-year variation in temporal trends of POPs. Cabrerizo presented further details of this work in a poster titled “Organic pollutants in snow and snow melting and its influence to high Arctic lakes and rivers.”
Amila De Silva, Environment and Climate Change Canada, presented a talk on a community-based seawater monitoring program for a full suite of organic contaminants and mercury in the Canadian Arctic. Results presented demonstrated that snow and ice melt each contribute different PFASs (longer chain vs. shorter chain PFASs) to surface marine waters, suggesting that climate-induced changes to the extent of sea ice and timing of annual melt will impact seawater PFAS levels and chemical profiles. The importance of community involvement to the success of the project was also discussed.
PhD student Karista Hudelson, University of Windsor, presented a 27-year monitoring study on mercury in five high Arctic char populations, showing breakpoints in four populations and a relationship between char mercury concentration and three key climate drivers. Hudelson suggested climatic drivers are exerting stronger influence over char mercury concentrations in more recent years and that climate change brought about a significant shift in the mercury bioaccumulation regime of the study populations. Muir presented a companion poster on a related project on “Increasing Mercury and Other Elements in Arctic Char from a Lake Undergoing Climate-Driven Changes.”
Natalia Quinete, Florida International University, presented a poster on the occurrence and tissue distribution of PCBs and OCPs in Magellan penguins (Spheniscus magellanicus) of Southeastern Brazil, which are migratory top predators and thus valuable marine pollution biomonitors. The study indicated greater influence of pollution by organochlorines of industrial origin and levels of PCBs in 25% of the samples above the threshold for toxic effects, which raises concern regarding the health risks these compounds pose to this threatened species.
This series of talks, as well as the lively question periods that followed, highlighted the vulnerability of Arctic ecosystems to climate-induced changes on the cycling and fate of variety of contaminants, including the release of previously stored legacy PCBs and OCPs to aquatic ecosystems. Further, the session demonstrated the importance of long-term monitoring of both abiotic and biotic components of the environment for assessing and predicting the effects of climate-induced alterations on contaminant levels in Arctic marine, terrestrial and freshwater wildlife used for food by Indigenous peoples. Finally, the session highlighted the importance of community participation and Indigenous knowledge to the success of scientific research and monitoring programs in remote Arctic regions.
Matt McCoole, Bayer CropScience; Paul Sibley, University of Guelph; Henry Krueger, EAG; and Teresa Norberg-King, U.S. Environmental Protection Agency
Sediment toxicity testing in support of sediment risk assessment has recently gained an increasing awareness within the scientific community. For example, in 2015, a scientific opinion on environmental risk assessment for sediment organisms was published by the European Food Safety Authority (EFSA). Sediment toxicity risk assessments are guided by the methods outlined in ASTM and by the USEPA sediment testing guidance documents (e.g., OCSPP 850.1735 ). There are a number of differences between the Organisation for Economic Co-operation and Development (OECD) and USEPA guidelines for performing spiked sediment tests, including the introduction of the compound into the test system, the use of natural or artificial sediment, equilibration time and flow-through or static test design. These test method differences lead to changes in the physicochemical properties of the sediment, bioavailability of the test compound and the concentrations of the test substance in the overlying water, porewater and bulk sediment. Due to these differences, the results of studies performed according to OECD and USEPA test methods are difficult to compare. In recent years, the environmental matrix (porewater, overlying water, sediment, bulk sediment, total loading) most strongly associated with effects has been widely debated. Therefore, being aware of differences between test methods and between guidances lead to uncertainty when comparing studies, including the relevant route of exposure and how to express test results to be used in the sediment risk assessment.
The overall goal of this session was to highlight applied and theoretical innovations associated with sediment toxicity testing to improve test methods and performance, interpretation of study results and to find ways to reduce uncertainty in the application of sediment toxicity data for ecological risk assessment. The “Current and Future Challenges in Sediment Toxicity Testing for Environmental Risk Assessment” was a half-day session that comprised eight platforms, touching on a wide variety of topics, including testing of non-standard test species, OECD vs. USEPA test methods, equilibration of test chemicals, probabilistic risk assessments, negative and solvent control functional equivalency, and analyses of contaminated sediment.
The platform portion of the session started with a discussion from Ted Valenti, Syngenta and in cooperation with Crop Life America, on the functional equivalency of negative and solvent control treatments from spiked-sediment toxicity studies. Results from the analysis support the position that elimination of the negative control treatment from spiked-sediment toxicity tests will not impact the robustness of the toxicity data as there is no functional difference between the two controls.
The next two talks were given by Hank Krueger, EAG. The first presentation described establishing equilibration of chemicals in porewater prior to conducting sediment toxicity test and included comparisons among equilibration guidelines (US vs. EU), and it provided recommendations on methods to choose an appropriate equilibration time for definitive sediment toxicity tests. The next talk given by Krueger focused on expanding the number of freshwater invertebrates used in acute toxicity tests in the registration of chemicals. The take away point from this talk highlighted the need for species-specific guidelines, with revisions to current guidelines to incorporate specific ecological requirements and challenges based on the species tested.
The fourth talk in the platform session was given by Trudy Watson-Leung, Ontario Ministry of the Environment, discussing improvements in feeding methods to Hexagenia spp. in various sediments. Based on this presentation, the session attendees learned that differences in feeding methodologies can have consequences on growth and survival, as well as potential implications on the interpretation of study results in sediment toxicity tests.
The next talk from Kent Woodburn, Dow Performance Silicones, discussed a fugacity approach to probabilistic risk assessment of cyclic volatile methylsiloxanes to benthic invertebrates. This presentation was based on a risk assessment method that combined fugacity and a probabilistic analysis of field monitoring data and results from chronic laboratory benthic toxicity studies using cyclic volatile methylsiloxane materials.
Xiaochun Zhang, Wisconsin Department of Natural Resources, discussed challenges in interpreting sediment toxicity test and analytical test results in coal tar contaminated sediment and development of cleanup benchmarks. The presentation showed the significant challenges that are encountered in developing cleanup benchmarks for contaminated sediment. Recommendations for interpretation of toxicity test results, including analytical uncertainties, presence of multiple contaminants, and the fate and transport of coal tar were presented.
The final talk in the platform session was from David Moore, US Army Engineer Research and Development Center, and compared the acute and chronic toxicity endpoints with benthic infaunal community measures. In this presentation, laboratory-based toxicity endpoints were compared to measures of benthic community health in exposed communities to evaluate the ability of toxicity tests to accurately predict observed impacts on the in situ community. The analysis showed that both acute and chronic laboratory-based sediment toxicity yielded highly conservative estimates of potential benthic community impacts compared with those detected in exposed field populations.
The session also had 10 poster submissions, covering a range of topics, including:
- Effects of acid volatile sulfides on Hyalella azteca (Andrew McQueen, US Army Engineer Research and Development Center)
- Functional equivalency of negative and solvent control in spiked sediment toxicity studies (Brian Snow, Smithers)
- Solvent residues in spiked-sediment toxicity studies (Kent Kabler, Syngenta)
- Natural versus formulated sediment in sediment toxicity testing (Henry Krueger, EAG)
- Sediment toxicity evaluations using fish embryos (Seiichi Uno, Kagoshima University)
- Sensitivity of D. magna and H. azteca to polycyclic aromatic hydrocarbons (PAHs) in sediment toxicity tests (Kazune Tani, The University of Tokyo)
- Stream sediment toxicity to H. azteca and C. dilutus (Nile Kemble, US Geological Survey)
- Impacts of metal-contaminated sediments to benthic communities (John Besser, US Geological Survey);
- Risk assessment of metal contaminated lake sediment (Jussi Kukkonen, University of Jyvaskyla);
- Sediment composition and toxicity of naphthalene sulfonates to T. tubifex (Ryan Prosser, University of Guelph).
Sediments are a non-renewable resource that provide a habitat for a diverse range of organisms, thereby delivering unique ecosystem services such as important biochemical transformations. Therefore, they play a key role for the ecological status of aquatic ecosystems. On the other hand, sediments represent both a major sink and a potential source of persistent toxic substances in aquatic environments. Complex biochemical and ecological interactions occurring within sediments require specific assessment tools for protecting benthic organisms and processes for environmental risk assessment. As illustrated in this session, improvements and refinement of sediment testing approaches and harmonization of approaches, where appropriate, is and must continue to be a major goal for both prospective and retrospective risk assessment.
Encouraged by the turn out of this session, a similar, yet expanded sediment toxicity session titled “Environmental Risk Assessment in Sediments” is being offered at the SETAC Europe 28th Annual Meeting, which will be held from 13–17 May in Rome, Italy. Sebastian Höss, Ecossa; Ute Feiler, German Federal Institute of Hydrology; Daniel Faber, Bayer AG CropScience; and Paul Sibley, University of Guelph, will chair this session.
Timothy J. Canfield, U.S. Environmental Protection Agency; Valery Forbes, University of Minnesota; and Christine Lehman, The Dow Chemical Company
Normative science (sometimes referred to as white hat bias) has been defined by some as a type of information that is developed, presented or interpreted based on an assumed (usually unstated) preference for a particular policy or class of policies. As ethical scientists, we are trained to let data and facts guide our conclusions as well as help define future hypotheses. However, as humans we have values, beliefs, morals and convictions that make remaining unbiased challenging, especially if we don’t recognize it. We potentially see this bias when we initially choose what area of research to pursue versus those we are not interested in pursuing.
But when we hear the term normative science, what are the images that come to mind? Do we, as a society and collection of scientists, view it as something that is a relatively minor departure from strict impartiality, or is it something more serious? When you mention normative science to colleagues, do they understand its issues, or are they more likely to respond back with what is normative science?
This session was designed to explore several questions about normative science. First and foremost, what is normative science? Is normative science a part of the environmental sciences and the research that is conducted? If so, how pervasive is it? Is it only a part of one sector (academia, government, business or nongovernmental organization) or does it manifest itself across multiple, if not all, sectors? This session explored the nature of normative science in environmental science, what it might look like, where it may be prevalent, and look to evaluate how pervasive it is (if at all) and how much of a concern it currently might be in the environmental sciences.
The session covered views from researcher across academia, business and government. This session was one of the recorded sessions, please check one or all of these talks.
The key points for the eight presentations included:
- Tim Canfield, U.S. Environmental Protection Agency, kicked off the session by giving an overview of the various forms of bias appearing in our science and differentiating normative science from other forms of bias. He concluded that we have a problem with normative science in our field and that we need to address it quickly to maintain the integrity of SETAC science and avoid the loss of public trust.
- Peter Calow, University of Minnesota, discussed the differences between scientific advocacy and scientific advice. He used Rachel Carson as an example of someone who provided a work couched as scientific advice that was heavily laden with and emanated from a position of strong scientific advocacy. Calow took the position that there needs to be a separation of the two and strongly supported the use of the scientific approach over the advocacy approach. He concluded that we need to protect the scientific process and that we need to be very transparent when we are including advocacy into the process.
- Kevin Elliott, Michigan State University, took a slightly different approach to the issue by suggesting that values are always a part of every effort, and instead of trying to eliminate values, we should identify key value judgements and be very transparent about them. Elliott contends that we are always faced with value judgements in the scientific process, especially when the available evidence does not clearly settle the questions being asked. He advocated striving to acknowledge crucial judgements and reflected on how to best address them, including being transparent, so others can clearly see when you are incorporating judgements and subject these judgements to critical scrutiny from a range of stakeholders.
- Anne LeHuray, Chemical Management Associates, focused her talk on bias and issues arising from the governmental sector and how to gather information to address these issues. She laid the foundation for her talk by asking the question “What happens if the government gets the science wrong?” LeHuray proceeded to describe the various avenues to try and gather information on the science from the government and the potential road blocks that are frequently encountered when pursuing this information. She concluded that although the government purports to be open and transparent with their scientific information, if there is a question about the information and conclusions, gaining access to the data is often difficult to obtain.
- Katherine Palmquist, Exponent, talked about how bias has affected published science and approaches to combat these biases. She cited a number of works, demonstrating that scientific literature contains bias, and it affects the reported results. Palmquist strongly supports a rigours open process where all data, sampling plans, methods and data analysis are available for review. She suggested a couple of tools that are currently available to help review publications for data inconsistencies. She concluded that bias must be combatted through external and internal approaches to be effective.
- Patrick Guiney, University of Wisconsin, started off his talk by stating “everyone comes into this world with a certain set of biases.” He acknowledged that everyone is influenced by where they work and that no sector is immune to the encroachment of bias. He provided several examples of how bias can enter into our works. Guiney champions that SETAC, as well as all of us, has a role to play in combating bias in our published and presented research, and he suggests several things that SETAC can look for to correct or better manage bias in the future programming and our published journals.
- With the untimely passing of Peter Chapman, G. Allen Burton, University of Michigan, with reluctance and humbleness, presented a talk about Peter Chapman and his impact on our science in honor of our departed colleague. He spoke of Chapman’s love of science and his boundless energy and enthusiasm to conduct high-quality science. Burton also spoke of Chapman’s love and great ability for reviewing articles and how he was one of the best in the business. Chapman devoted a great deal of his time to helping students grow in the sciences, and he took a keen interest in helping them to succeed. Burton concluded by telling the hushed audience that above his devotion for science, Chapman passionately loved his family above all else, which provide the foundation for everything he did in life. Chapman will be deeply missed by all of SETAC and especially by the colleagues that know him best.
- Chris Mebane, U.S. Geological Survey, rounded out the session by speaking on scientific integrity issues in environmental science. He started out by highlighting the widespread reports of unreliable science. Mebane spoke of a proactive effort by SETAC of forming a group looking into scientific integrity issues within the society. He talked about ways to combat these problems and also about the unintended consequences that can arise from implementing some of the solutions to address these problems. Mebane concluded that we have to be as open and transparent in our work as practical, we have to aggressively look to identify and avoid conflict of interest situations, and we need to develop and encourage sharing as much data as possible. He acknowledged that the issue is complicated and there are no easy answers.
Conclusions from the Session
Between 450 and 500 participants showed high interest in the session and joined a lively and interactive discussion. The comments and input from the audience made clear that there is a strong, shared concern by many in the Society that this is a problem and that there is interest across all sectors to address these issues. A number of participants expressed a desire to see more sessions focused on this topic to not only identify where these issues may arise but also to explore practical approaches to combat these issues of bias. This session was a perfect lead into the daily keynote presentation immediately following by Glenn Begley with BioCurate Pty, Ltd, who addressed “Ten Percent of the Time Works Every Time, or How to Recognize Sloppy Science.”
Nancy Golden, Sarah Warner and Dave Warburton, U.S. Fish and Wildlife Service (USFWS)
Prairie ecosystem pollinators have struggled with drastic reductions in their habitat, and many are now experiencing further declines that have led to their consideration as state or federal species of concern. To address this matter, the session examined the role of contaminants, especially pesticides, in the decline and research and regulatory mechanisms currently in place to protect these species. Topics were related to protection of prairie pollinator species, including toxicity research, contaminant exposure, conservation and management, and regulation of contaminants.
National-level research, risk management challenges and regulatory issues were discussed, as well as the urgency concerning the population declines of prairie species from Midwestern states. Local experts conducting research, management and policy activities from state, federal and private sectors addressed the latter. Given the wide scope of presenters, the session brought together and connected practitioners from various aspects of risk assessment and risk management.
Session chair Sarah Warner, USFWS, gave a brief introduction to the session and challenged attendees to think of the talks in a holistic manner, with a goal of connecting our seemingly separate and varied roles to be more effective at lowering the risk of pesticides to prairie pollinators. Dave Warburton, USFWS, set the stage by detailing the decline of specific pollinator species and laying out a framework for translating risk assessment science into risk management actions for these species. The complexity of selecting the appropriate inputs, implementing and communicating the risk management, and evaluating conservation actions was highlighted.
Recognizing and managing pesticide exposure in prairie habitats was further discussed specifically by the next two presentations. Erik Runquist, Minnesota Zoo, presented results from sampling in prairie habitats, where pesticide drift from adjacent agriculture pest management had resulted in the detection of pesticide residues in habitats of two critically endangered and quickly declining lepidopterans, the Powesheik skipperling and Dakota skipper. Toxicity studies are currently underway to ascertain the risk from pesticide exposure to these species. To combat pesticide drift, the Minnesota Department of Agriculture responds to and enforces complaints through investigation and penalties ranging from warnings to monetary fines to a license revocation as described by Rajinder Mann, Minnesota Department of Agriculture. While pesticide drift is thus recognized as a problem by Minnesota, this system is reliant upon a system of active reporting and is likely to receive reports from areas that are actively monitored, such as agricultural crops, as opposed to unoccupied natural areas.
Further research and assessment of contaminant toxicity to pollinators is being conducted on local and national scales. Ana Chicas-Mosier, Oklahoma State University, described research revealing that aluminum ingestion in honey bees may be detrimental to foraging and other ecologically relevant behaviors. With most of the session focused on pesticides, this study provided an important reminder of other contaminant stressors in the environment and impacts to pollinator health. The U.S. Environmental Protection Agency’s honeybee toxicity testing and risk assessment methodologies were presented by Justin Housenger, USEPA, as a means to describe the agency’s protection goals of pollination services, hive products and biodiversity. These requirements and guidelines represent a major advancement in the analysis and regulation of pesticide effects to terrestrial invertebrates. Though, the applicability of these methodologies to terrestrial and native invertebrate species, other than the non-native honeybee, may be questionable in some cases, and the development of alternate methods may be necessary to accurately determine exposure and effects to native species.
Moving to a landscape level, participants explored strategies to effect change in the field. Steve Bradbury, Iowa State University, presented research being conducted in his laboratory, including toxicity testing of specific pesticides to lepidopterans, and the application of those results to pesticide drift exposure. Based on these parameters, Bradbury provided estimates of the amount of habitat needed to be conserved or restored to generate a positive impact to the species in areas near pesticide use. Finally, Dave Perkins, Waterborne, addressed the need for evaluation of conservation initiatives and associated impacts on pollinator protection. Suggested solutions involve developing strategies that include taking into account the characteristics of land use change and management and pollinator life history features through programmatic conservation initiatives that yield the most benefit for pollinator protection.
Conclusions from the session included:
- The current decline in prairie pollinators is indicative of an application and management system that is not fully protective of these species.
- There is a shift in focus towards protection of pollinators, but even new paradigms may not be fully protective of all species or represent all possible effects.
- Protection of prairie pollinators requires development of science, risk assessment, risk management and regulation policy that is meaningful and relevant to the species we are trying to protect, sensitive to current land uses, and flexible to monitoring and adaptive management.
- There are dedicated practitioners from various aspects of risk assessment, risk management and the regulatory cycle. Creating better links and communication will help facilitate protection goals.
Work continued following the session as several attendees and presenters gathered to discuss avenues of collaboration over Pollinator Lunch as well as a Pollinator Happy Hour. Research ideas and next steps were brainstormed, and contacts and connections were developed further.
Summaries Published in the February 2018 Issue
Chris McCarthy, Jacobs, and Christopher Salice, Towson University
Per- and polyfluoroalkyl substances (PFAS) have been measured in environmental and biological tissue samples around the world and even in areas far removed from likely sources. However, published toxicological research to date has focused predominantly on perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) and for only a limited number of organisms. The lack of robust and defensible ecotoxicity data for some taxa and for most PFAS other than PFOA and PFOS hinders risk assessment and may lead to unsupported risk management decisions. Given this gap in understanding of PFAS ecotoxicity, there is a strong need for further research on PFAS including those on the Unregulated Contaminant Monitoring Rule 3 (UCMR3) list and beyond. This session served as a forum for presenting the latest research results on the ecotoxicity of PFAS beyond PFOS and PFOA, research on the ecotoxicity of all PFAS using under-represented organisms, and how to focus ecological risk assessments for PFAS.
The session covered views from academic researcher institutions conducting laboratory experiments, researchers working closely with the U.S. Department of Defense at installations that formerly used PFAS-containing aqueous film forming foam (AFFF) products and consultants working within regulatory frameworks as ecological risk assessors evaluating the potential for adverse effects from PFAS. Interest for the session was strong with a steady attendance of 90 participants throughout the afternoon, and engaging comments and questions following each platform talk.
The presentation by Andrew East of Towson University helped focus the problem that exists for U.S. military installations that formerly used AFFF by examining the patterns of PFAS detections in installations across the U.S. The results were then used to examine prioritization schemes for future testing of relevant PFAS mixtures. This work also identified that common components of these mixtures are seldom studied compounds (e.g., perfluoro hexane sulfonate [PFHxS] and perfluoro butane sulfonate [PFBS]). Many of the presentations in the second half of the session specifically highlighted work with these chemicals. A presentation by Steve Bursian of Michigan State University described differences in acute toxicological response of Japanese quail (Coturnix japonica) exposed to perfluoro octane sulfonate (PFOS), perfluoro octanoic acid (PFOA), and AFFF mixtures from 3M and Ansul. Gary Hoover of Purdue University then discussed the results of exposure of larvae of two amphibian species, eastern tiger salamanders (Ambystoma tigrinum) and American toads (Anaxyrus americanus), to PFHxS and other PFAS. This study provided an in-depth exploration of potential effects of PFAS on growth, development and endocrine disruption at environmentally relevant doses on U.S.-native amphibians. Chris McCarthy of Jacobs then presented preliminary results of individual exposures of six different PFAS, including those identified in the Towson University mixture scheme, to the midge (Chironomus dilutus).
Presentations by Christopher Salice of Towson University and Adric Olsen with Texas Tech University focused on evaluating potential ecological effects at Barksdale Air Force Base (BAFB). Adric Olsen presented a spatially explicit PFOS uptake and depuration model for fish, which closely approximated field measured concentrations from BAFB. Salice presented a probabilistic risk assessment, examining the likelihood of exceeding a variety of available thresholds. Jennifer Arbrister of GeoSyntec then presented a detailed analysis of species sensitivity distributions (SSD) that were used to develop the recently published draft protection values from the Australian Department of the Environment and Energy. Arbrister’s work highlighted how a single toxicity value for zebrafish (Dario rerio) was exerting a strong influence on the SSD and subsequent protection values. Jason Conder of GeoSyntec presented highlights of how to focus ecological risk assessments for PFAS, and his conclusions matched well with other presentations noting PFHxS as a key PFAS to focus on in future toxicity testing. Conder also pointed out that work specifically with avian species may be the key driver in aquatic foodwebs due to the bioaccumulative nature of these chemicals and the importance of fish consumption and incidental ingestion of sediment in their diets.
Conclusions from the session were that much work is still needed to understand what level of risk environmentally relevant concentrations of PFAS pose to environmental receptors. The ongoing laboratory research is starting to broaden the understanding of species-specific effects thresholds for PFAS. However, the connection with real-world concentrations and whether they could be posing an unacceptable risk to the environment is still uncertain. The consensus is that the existing base of data is not sufficiently strong or well tested to support robust remedial action. As one presentation suggested, the order of magnitude difference in effect levels used for developing the most stringent of the Australian aquatic life protection value is quite large and points to the need for additional data even for well-studied PFAS such as PFOS.
The session provided an excellent opportunity to gain familiarity with ongoing PFAS research, learn how ongoing research projects relate to each other and identify the remaining research needs. Work associated with many of these presentations has either recently been published or is currently in review, emphasizing the importance and demand for this research.
Annie Krueger, Bayer; David Lehman, US Environmental Protection Agency; Cynthia Scott-Dupree, University of Guelph; and Daniel Schmehl, Bayer
Pollinators have been in the spotlight of ecotoxicology risk assessment since the mid-2000s with concerns for declining honey bee (Apis mellifera L.) health in Europe and North America. For regulatory authorities, the current risk assessment paradigm for insect pollinators has utilized the honey bee as the model organism for addressing regulatory protection goals. Robust methodology has been developed to characterize the risk of agrochemicals to honey bees, individually and at the colony level. However, there is uncertainty in whether species’ differences in biology and exposure allow risk assessments based on the honey bee to be protective for other (non-Apis) bees. This session provided a forum for scientists from government, business and academia to explore how studies can be adapted to refine current bee risk assessment paradigm through current advancements in method development and data generation.
Platform Presentation Summaries
Extrapolating Acute Toxicity Across Bee Species – The Influence of Size (Abstract #89)
Helen Thompson, Syngenta Ltd; Jay Overmyer, Syngenta Crop Protection, LLC
Thompson and Overmyer presented:
- Bee species differ widely in body mass (i.e., 43-fold difference).
- Accounting for body weight is routine for toxicity studies, but this approach has not typically been applied to bees.
- Using dose calculations based on body weight may serve as a starting point for looking at differential sensitivity across other bee species for acute toxicity endpoints.
- Ecology and behavior assessments will be necessary to characterize potential differences in the likelihood of exposure.
Taxonomic Relevance of an Adverse Outcome Pathway Network Considering Apis and Non-Apis Bees (Abstract #90)
Carlie LaLone, US Environmental Protection Agency (USEPA)
LaLone presented in her talk that:
- A putative adverse outcome pathway (AOP) network was developed, linking activation of the nicotinic acetylcholine receptor (nAChR) to colony losses in honey bees.
- The USEPA Sequence Alignment to Predict Across Species Susceptibility (SeqAPASS) tool was used to investigate the domain of applicability of this AOP network.
- Results suggest that SeqAPASS may help identify species for which honey bees are an appropriate surrogate.
Summary of an International Workshop on Pesticide Exposure Assessment for Non-ApisBees (Abstract #91)
Silvia Hinarejos, Valent U.S.A. LLC
Hinarejos presentation included:
- Experts in non-Apis bee ecology and risk assessment from regulatory agencies, crop protection and academia participated in a meeting titled “Workshop on Exposure Assessment Paradigm for non-Apis Bees” in January of 2017.
- While participants generally agreed that the current honey bee exposure assessment paradigm is protective for non-Apis bees, several routes of exposure were identified where honey bees may not be fully protective; however, at this time, it is not possible to parameterize exposure equations for these novel pathways.
- Several exposure routes (e.g., soil) were highlighted that the honey bee does not adequately model.
Exploring Routes of Pesticide Exposure Risks to Solitary Bees (Abstract #92)
T. Pitts-Singer, U.S. Department of Agriculture (USDA); F. Sgolastra, University of Bologna; N. Boyle, USDA; A. Kopit, Utah State University; and J. Bosch, CREAF-Autonomous University of Barcelona
Pitts-Singer et al. reported:
- The alfalfa leafcutting bee (Megachile rotundata) may be an ideal candidate to serve as the surrogate species for North American solitary bee risk assessments because its biology is reasonably well-understood, it is commercially available and there are ecotoxicology data available for this species.
- Alternative surrogate species to the honey bee will allow for better exposure models via nest matrices (e.g., leaves or mud).
Megachile rotundata: A Potential Model for Non-Apis Bee Risk Assessment (Abstract #93)
Andrew Frewin , Angela Gradish, G. Ansell, Cynthia Scott-Dupree, University of Guelph
Frewin et al. presented that:
- Currently, there are no internationally validated methods for solitary bee toxicity testing.
- The honey bee may not be appropriate for modeling exposure to alfalfa leafcutting bees due to a prominent route of exposure through the leaves or nesting material; however, there are many challenges to generating data for this species in the field.
- Primary focus of this research was to develop semi-field risk assessment methodologies using small screened tent enclosures in fields of alfalfa, phacelia and buckwheat.
- Suitable endpoints, reference toxicants and acceptable validity criteria will need to be defined for M. rotundata studies to overcome variability in in control performance.
Development of a Semi-Field Method for Use in Pesticide Risk Assessments with Bombus impatiens (Abstract #94)
Angela Gradish , T. Celetti, University of Guelph; C. Cutler, Dalhousie University; Cynthia Scott-Dupree, University of Guelph
Gradish et al. presented that:
- Although the Organization for Economic Cooperation and Development (OECD) recently validated protocols for acute contact and oral toxicity testing in bumble bees, there are no standardized methods available for semi-field toxicity studies.
- Continued development of this semi-field method for bumble bee toxicity testing is encouraged because it incorporates a cost-effective containment strategy that increases the number of experimental replicates and may also reduce experimental variability typically observed with bumble bees.
- Results of studies on Bombus impatiens – a North American species of bumble bee, indicate that it is more sensitive to the toxic reference standards being testing than B. terrestris –a European bumble bee species used in toxicity testing in Europe and some other countries.
- Suitable endpoints, reference toxicants and acceptable validity criteria will need to be defined for bumble bee colony studies to overcome variability in colony condition.
Field-Level Exposure of Bumble Bees to Fungicides in a Cherry Orchard (Abstract #95)
Kathryn Kuivila , United States Geological Survey (USGS); J.P. Strange, USDA; H. Judd, Utah State University; Michelle Hladik, C.J. Sanders, M.M. McWayne, USGS
Kuivilia et al presented that:
- Hunt bumble bees (Bombus huntii) were deployed in a commercial cherry orchard in the spring of 2016. One group of seven hives was placed next to an orchard block sprayed with the fungicides boscalid and pyraclostrobin and a control group was placed 400 meters away.
- In the nectar and pollen collected, boscalid and pyraclostrobin concentrations had the same ratio as the pesticide formulation.
- Nectar concentrations varied spatially by hive and temporally. The highest fungicide concentrations occurred one or two days after spraying: up to 251 ng/mL boscalid and 137 ng/mL pyraclostrobin.
- The primary and secondary sources of bee-collected pollen were identified though microscopic visual examination of each bee corbicular load. Pollen from cherries contained the highest concentrations of the fungicides.
- New sampling strategies have been developed for collecting pollen and nectar from bumble bee colonies to determine in-hive residues. However, minimum sample weights will need to be defined moving forward.
Evaluating the Potential for Bumble Bee Microcolonies to Inform Risk Assessment (Abstract #96)
David Lehmann, USEPA
Lehmann summarized that:
- The USEPA is engaged in the identification of potential tests for assessing the impact of pesticides on bumble bees.
- The USEPA incorporates data from non-Apis bees into pesticide risk assessments on a case-by-case basis.
- Data generated from bumble bee microcolonies may be a useful tool for risk assessors, but only after further method development and ring-test validation.
Major Conclusions of the Session
- The honey bee serves as the surrogate species for the current insect pollinator risk assessment paradigm; however, further research and workshop efforts will aim to validate differences in toxicity and exposure between the honey bee and non-Apis bees.
- There is an ongoing international effort involving scientists representing regulatory agencies, industry and academia to determine if additional risk assessment approaches are required.
- Several species of solitary and social non-Apis bees have been proposed as representative (i.e., surrogate) species for different regions to generate toxicity and exposure data for potential use in bee risk assessment.
- A variety of in silico, laboratory-based and semi-field approaches are being developed for investigating the effects of environmental stressors on non-Apis bees. These tools may be useful for making inter-species comparisons.
- While significant progress has been made, there are a number of challenges for including non-Apis bees into a comprehensive pollinator risk assessment including:
- Availability of quantitative life history data
- The need for validated robust testing methods with low control endpoint variability
- Limited commercial availability and standardized animal husbandry practices
- Identification of appropriate assay endpoints for regulatory decision-making
- The need for proper reference toxicants integrated within a relevant test matrices
- Limited species sensitivity data for non-Apis bees in comparison to the honey bee
- To be most useful to risk assessors, measurement endpoints from new methodologies must have an unambiguous linkage to traditional apical assessment endpoints (i.e., survival, growth, development and reproduction).
Concluding Thoughts from the Session Chairs
This session discussed ongoing efforts to develop tests specifically for non-Apis bees. In order to be fully utilized, these methods must be subjected to validation efforts to determine their suitability within an insect pollinator risk assessment paradigm and confirm their sensitivity, specificity and reproducibility among different laboratories. In the absence of rigorous validation, the value of these methods will be limited.
Disclaimer: The contents described within this article does not necessarily reflect the views and policies of the authors or their affiliated institutions, including Bayer or the USEPA.
The research described in this article has been reviewed by the National Health and Environmental Effects Research Laboratory, USEPA and approved for publication. Approval does not signify that the contents necessarily reflect the views and policies of the agency, nor does the mention of trade names of commercial products constitute endorsement or recommendation for use.
Jonathan Challis, University of Manitoba; Heidi Swanson, University of Waterloo; Douglas Stevens, Salish Kootenai College; and Diana Cryderman, Bay Mills Community College
Scientists within SETAC are tackling complex environmental questions around the fate and effects of contaminants and their implications for environmental and human health. In many cases, this research takes place on Indigenous lands where the social aspects of our science should be at the forefront. Conducting science on traditional lands must involve meaningful consultations and engagement with Indigenous communities and cultural competency on the part of the researchers. However, many scientists have not been adequately mentored in developing rapport and relationships with Indigenous research partners or stakeholders. The goals of this session were to highlight ongoing collaborative research efforts with Indigenous communities, illustrate the strengths and challenges of successful collaborations that bridge research and community engagement, and discuss links between western science and traditional knowledge systems.
This was the first session of its kind at SETAC North America and was designed to build on momentum initiated at the 2016 Asia-Pacific meeting, where a similar session took place. As a result of that session, the Indigenous Knowledge and Values Global Interest Group (IK&V IG) was officially formed. The newly formed IK&V IG held a meeting the day before our session to discuss the role of Indigenous knowledge within SETAC and the need for greater Indigenous representation and support in all aspects of SETAC science. The group had a productive discussion, which served as an excellent primer for our session the following morning.
The session was well-attended on Thursday morning, with an average of 36 people per presentation for the seven platform talks. Co-chair Diana Cryderman began by acknowledging the traditional Ojibwe and Dakota lands on which the conference was held and introducing John Doyle of the Crow Tribe, who opened the session with a prayer. Co-chair Heidi Swanson kicked things off with an engaging presentation on her work with Kluane First Nation in Kluane Lake, Yukon, where the Nation and university researchers collaboratively studied contaminant burdens (mercury and POPs) in food fishes from Kluane Lake. A major aspect of the work involved a youth exchange that saw a number of young community members visit the laboratories where fish samples were being processed and analyzed. The work serves as an excellent model for how community-driven research and two-way knowledge exchange can be successful. The community documented the project in a short video they created, entitled “Remembering our Past, Nourishing our Future.”
All of the presentations in the session exemplified honest and respectful partnerships between researchers and tribal and Indigenous communities. Matthew Dellinger of the Medical College of Wisconsin partnered with two inter-tribal groups in Michigan to develop fish advisories around mercury and PCBs that are more accessible and culturally sensitive to the Anishinaabe peoples living in the Laurentian Great Lakes region. These advisories were integrated into a cellphone app that utilized traditional Anishinaabe words (e.g., Gigiigoo’inaan means “our fish”) and art in an interactive interface that determined safe consumption ranges based on the bodyweight, age and sex of consumer, as well as the type of fish. The partnering organization, Inter Tribal Council of Michigan, recruited 24 Anishinaabe adults who tested the usability, influence on dietary behavior and cultural appropriateness of the app. The response to the app was overwhelmingly positive, and a second year of study with more participants is planned.
Jack Bend of the University of Western Ontario discussed collaborative work with the Walpole Island First Nation. Decades of water and airborne industrial pollution has led to the closure of the Nation’s commercial fisheries. A community-based research approach was used to assess mercury and arsenic levels in human hair, water, sediments and food fishes. Ph.D. student Mary-Claire Buell from Trent University discussed her work investigating contaminated sediments in Owen Sound Bay, Lake Huron, in partnership with two First Nations Communities and the Natural Sciences and Engineering Research Council (NSERC) CREATE H2O Program. Traditional ecological knowledge and community engagement was the basis for which Buell developed a risk evaluation framework that better encompasses community perspectives and values.
John Doyle from Little Big Horn College and Margaret Eggers from Montana State University gave a joint presentation discussing contaminants in well water in Crow Reservation, Montana. As a collaborative effort between Tribal members and academic partners, all work on traditional lands was conducted by Tribal members and Crow student interns. Based on hazard index calculations, 24% of the wells contained unsafe water due to uranium, manganese, nitrate or arsenic. This work integrated community knowledge resources and Tribal environmental expertise to address important, culturally sensitive questions around well water safety.
Tracey Godfrey, co-chair of the IK&V IG, travelled from New Zealand to share a holistic approach to addressing a legacy of contamination from industrial timber treatment activities, based on the intimate connections Indigenous groups share with their land. For the Indigenous community Ngati Awa, this approach relied on ancestral connections to the environment and acknowledging that these relationships with the environment are linked to the past and the future. Preservation of these linkages, in part, relies on remediation of these contaminated environments, and thus obvious congruence’s between western science and Indigenous values were identified.
The session was brought to a close by Douglas Stevens from Salish Kootenai College, who discussed his work with the Center for the Native Environmental Health Research (NEHR) Network. The NEHR Network works to link tribes with research and human resources at tribal colleges and Native-serving universities, with the goal of addressing pressing environmental health issues. Two examples of ongoing community-based collaborative environmental health research projects funded through the Center were highlighted. One included faculty and students at Salish Kootenai College working directly with tribes in northern Maine as well as with Ojibwe communities in the Upper Peninsula of Michigan through their respective two-year tribal colleges to assess mercury and arsenic exposures. The second involved Native researchers at Northern Arizona University partnering with students and faculty at Dine’ College to assess uranium exposure to Navajo tribal members through sheep consumption. The center has been using the NEHR model to successfully conduct community-based collaborative environmental health research directly with tribes in northern Maine and the Upper Peninsula of Michigan. The approach has been extended to include other tribal colleges with great success.
By any measure, this session was a resounding success and demonstrated the interest and need for more Indigenous and Native representation within SETAC. The research discussed in this session highlighted that community engagement and consultations are fundamental to addressing environmental issues. We hope that the success of this session will produce the necessary interest within the SETAC community and governance structure to elevate, support and promote similar efforts moving forward.
Karel De Schamphelaere, Ghent University; Joe Shaw, Indiana University; and Kaley Major, University of Massachusetts Boston
Anthropogenic pollution can be a significant cause of environmental degradation. As society continues to depend on chemicals, substances continue to enter the environment, and populations may continue to be impacted by these contaminants. However, the effects of chemical pollution are not necessarily limited to the exposed generations. Examples of epigenetic and evolutionary effects have been documented for some contaminants, although there is a need to further elucidate such impacts. Gaining a better understanding of the mechanisms underlying these multigenerational effects of anthropogenic pollution will give insights to long-term risks of chemicals. Further, these evolutionary and transgenerational effects present a new challenge for environmental risk assessment.
Key Topics and Points of the Seven Session Talks
Nathan Keith and Joe Shaw explored the link between epigenetic patterns, oxidative stress and patterns of genome-wide mutation. Using the model organism Daphnia pulex and cadmium as an oxidative stressor, they have begun to address the underlying mechanisms linking toxicant exposure and structural DNA changes, additionally exploring mutation rates and fitness costs.
Elias Oziolor and Kaley Major focused on the genetic, evolutionary changes that occur in natural populations as a result of contaminant exposure. Environmental exposure to toxicants, including polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs), polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) has led to a genetically heritable resistance to these chemicals in the Gulf killifish (Fundulus grandis). Pyrethroid pesticide exposure has caused evolved resistance in the non-target amphipod, Hyalella azteca.
Epigenetic effects of the Deepwater Horizon oil spill were explored by Elizabeth Jones and Genbo Xu. In the sheepshead minnow (Cyprinodon variegatus), early life exposures to oil altered DNA methylation in developing fish, while other environmentally co-occurring stressors like hypoxia induced a very different transcriptomic response. In mahi-mahi (Coryphaena hippurus), the role of microRNAs in mediating cardiotoxicity of oil-exposed fish was explored on a genome-wide scale.
Donald Tillit documented transgenerational phenotypic inheritance from developmental exposure to atrazine in medaka (Orizias latipes).
Conclusions From the Session
Previous work in this study area has mainly focused on documenting pollution-induced epigenetic and evolutionary changes in populations in a descriptive way. This session showed that our understanding of these processes is increasing, moving toward the elucidation of the mechanistic basis of these changes. As we continue to work toward determining the mechanisms responsible for these population-level changes, we are gaining the capacity to predict the evolutionary and transgenerational effects of contaminant exposure. Such a capacity is likely to better inform ecological risk assessment.
VelRey Lozano, U.S. Environmental Protection Agency (USEPA); Rami Naddy, TRE Environmental Strategies, LLC; and Amy Bergdale, USEPA
Combining chemical-specific analyses in the form of water quality standards and biological monitoring with Whole Effluent Toxicity (WET) testing provides useful information to guide management decisions in environmental discharges. WET testing has been a permitting tool since 1995 under the USEPA National Pollutant Discharge Elimination System (NPDES). In 1998, USEPA WET test methods were scrutinized, and subsequently in 2002, the methods were updated to clarify procedures and ensure reproducibility, efficacy and precision. While the required WET testing methods promulgated in the U.S. Clean Water Act Regulations have been approved, scrutinized and re-approved, these methods continue to be questioned due to a myriad of concerns.
The SETAC session opened the floor for presenters to air these concerns. Participants discussed limitations of chemical-specific analysis methods, whether chemical-specific aquatic toxicity data are inadequate, and whether chemical-specific criteria adequately predict the toxicity of effluent chemicals to aquatic organisms. Additionally, discussions aimed at the laboratory level focused around national accreditation programs (i.e., The National Environmental Laboratory Accreditation Council [NELAC] Institute), and questions regarding the Discharge Monitoring Report Quality Assurance programs with an emphasis that both needed enhancements. New test methods, strategies, endocrine disruption screening methodologies, in vitro assays and various adverse outcome pathway (AOP)-based approaches were presented in this session.
The session and following discussion covered views from different experts and stakeholders from academia, government, industry and private WET laboratories. Attendees expressed interest in a future session, focused on the common core questions relating to alternative test procedures and regulatory alternatives, and more notably, questions regarding laboratory practices, regulatory limitations and the need for increased training in all areas of WET testing.
The key points for the presentations included:
- Phiwinhlanhla Ngwenya presented the preliminary findings from her research on the wastewater impacts to two rivers utilizing the species western mosquitofish (Gambusia affinis). Her research illustrated the potential use of this species as a surrogate for the currently approved species contained in the WET guidance. Future studies are needed to improve data sets to determine if data were comparable. Post-presentation questions focused on the use of alternative species versus traditionally approved species.
- Justin Scott provided an evaluation of fish gill cell line (RTgill-W1) comparing in vitro with in vivo effects. His research supports the development of current work in this area and efforts to provide alternatives to current WET test methods.
- Lauren Kristofco provided background on the continuing research being done by Shell Oil company to find alternative toxicity testing methods for use by industry in meeting NPDES permit limitations. Her research supports the evaluation of non-living organism alternatives in place of living organisms for testing which is consistent with the concerns that using living organisms is inhumane and should be phased out of scientific studies as soon as practical.
- Stephen Clark of Pacific EcoRisk discussed the problem of variability in test results using the same test species across laboratories in the California region. Application and administration of NPDES permit limitations was a focus of the noted variability causing lower comparability rates among labs. Clark stated this variability was negatively affecting the confidence in the validity of this data for regulation. Clark called for greater dialogue among experts doing this testing to reduce this variability and increase confidence that these data are sound for both the regulated community that has to meet these regulations as well as the regulating agencies that require compliance.
- Natalie Love, GEI Consultants, presented her research utilizing the four-day Daphnia magna test developed by James Lazorchak, et al. Her research provided insight into the use of the test and its applicability within NPDES testing. During the discussion session, Love addressed questions that were raised concerning how appropriate versus applicable the four-day Daphnia magna test was for use when doing these evaluations.
- William Goodfellow discussed compliance within NPDES permitting utilizing the Test for Significant Toxicity (TST) approach versus the Technical Support Document (TSD) approach. The differences between these two approaches and the applicability to the NPDES permitting guidance methods sparked lively debate. Goodfellow further clarified the differences between the performance of WET testing versus the permitting approach or statistical analysis of test results and the need for further discussions and understanding.
- The session presentations ended with Rami Naddy discussing the value and challenges of WET as a compliance tool. In this session, the presenter provided a clear illustration of the challenges within and between laboratories. Naddy discussed the current concerns regarding parity among WET laboratories – differences in the outcomes of WET data due to lack of clarity in NPDES permits and concerns regarding audits performed on WET testing by auditors not experienced with WET procedures and practices.
Conclusions From the Session
The session made clear that, as research continues, questions regarding the usefulness of WET testing continue. The session further illustrated how the proper application of the approved regulatory tools remains one of the greatest sources of WET testing concerns. Important aspects that need to be considered in the NPDES permitting program are the variation in application of WET test analysis requirements as described in NPDES permits.
Researchers continue to develop new testing methods in response to growing ethical concerns surrounding the use of live organism or embryo-larval stage organisms. However, regulatory limitations and confusion remain an impediment for the advancement of science in the WET field. The efficacy of the WET test methods is largely affected by inadequate permitting guidance, training and general WET test method knowledge.
Summaries Published in the December 2017 Issue
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
The 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.
A 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:
- 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.
- 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.
- 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).
- 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.
- 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.
- 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.
- Resistance of invasive Great Lakes sea lamprey to a commonly used lampricide does not appear to correlate with historical exposures.
- 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.
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.
Kay T. Ho, Robert M. Burgess, USEPA, Narragansett, RI and Susan B. Kane Driscoll, Exponent, Maynard, MA
While 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.
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.