Summaries Published in the March 2019 Issue
Carys L Mitchelmore, UMCES Chesapeake Biological Laboratory, and Iain Davies, Personal Care Products Council
The session’s goal was to bring scientists and stakeholders from academia, business and government agencies together to discuss the emerging field of research regarding the environmental risk of UV filters in aquatic ecosystems. The session chairs reached out to the primary authors that had published papers on the environmental risk of UV filters to coral ecosystems given that this was a current hot topic of concern.
Ultraviolet filters are the active ingredients in sun protection products, such as sunscreens, although they are also present in other consumer products, for example plastics, paints and apparel. There are multiple point and diffuse sources of UV filters to the aquatic environment, including swimmers, wastewater treatment plants as well as run-off from land uses due to leaching from products.
Recently, there have been concerns over the impact of UV filters to corals, leading to legislative activity in Hawaii that resulted in the banning the sale of two UV filters, namely oxybenzone and octinoxate. This action was essentially driven by a study conducted in 2016, which showed the presence of oxybenzone at one of seven sites near coral reef locations in Hawaii and toxicological impacts to coral planula and in coral cell lines exposed to oxybenzone. As an emerging field of research, there are only a few studies that have reported on the concentration of UV filters around coral reefs and even fewer studies investigating toxicological impacts in corals.
Risk assessments require both of these data sets, including knowledge of the concentration of the chemical of concern in the aquatic environment and the concentrations that cause damage to the species of interest. Therefore, the current session brought together researchers, who have investigated the occurrence, fate and effects of UV filters in the environment, with industry representatives to discuss environmental risk and the potential trade-offs with human health concerns. The session aimed to advance our knowledge of the environmental risk that such materials pose and to initiate scientifically grounded discussions.
Key points from the seven presentations included:
- Iain Davies (Personal Care Products Council) introduced the session by setting the scene and giving an overview of the state of the science and challenges regarding environmental risk assessments of UV filters in the aquatic environment and highlighting numerous data gaps.
- Given the current concern regarding the potential for negative impact of UV filters to Hawaiian coral reefs, coupled with the limited amount of data available to conduct a risk assessment, especially regarding environmental concentrations of UV filters in Hawaii, Carys Mitchelmore (UMCES, Chesapeake Biological Laboratory) presented data from a recent monitoring program measuring the concentration of 13 UV filters in seawater, sediment and coral tissues at various sites in Oahu, Hawaii. She concluded with a summary of the studies relevant in relation to environmental risk by using published toxicological thresholds.
- Broadening the discussion of consumer chemical pollutant risks to coral reefs, Michael Gonsior (UMCES, Chesapeake Biological Laboratory) followed up on the previously described Hawaii monitoring project by demonstrating the utility of a non-target chemical screening approach that revealed a diversity of surfactants and their degradation products also present in seawater, which may also be of concern to coral health.
- Very little is currently known regarding the environmental fate of UV filters, and Sara Wolfson (Rutgers University) gave an overview of some potential transformation products of UV filters arising from microbial activity in wastewater treatment plant effluents, which is relevant to their impact to aquatic organisms receiving this effluent.
- Addressing the second component of a risk assessment, new UV filter toxicity studies were presented by both Ray Banister (Mote Marine Laboratory) and Marc Leonard (L’Oréal). The first study demonstrated mortality in corals after nine days exposure to 3 mg/L oxybenzone and chronic impacts at concentrations of 0.3 mg/L. The study also highlighted changes to the host microbiome at the highest concentration. The L’Oréal study was a longer-term chronic exposure study investigating changes to photosynthetic activity in corals exposed to an array of organic UV filters, the mineral UV filter Zinc oxide (ZnO) and other aquatic contaminants, for example, herbicides (Monuron and Diuron) and antifoulant paint (Tributyltin). Photosynthesis was impacted more by ZnO and especially the other contaminants used than the other organic UV filters, which showed no adverse effects on the symbionts or animals up to their water solubility limits.
- Summarizing the session to balance the discussion between environmental risk and human health consequences, Jay Sirois (Consumer Healthcare Products Association) highlighted and summarized concerns from the industry and health professionals regarding the implications and problems with removing organic UV filters from use.
Conclusions From the Session
The environmental risks of UV filters in aquatic environments is an emerging field of research, and there are numerous gaps in knowledge critical for risk assessments. Much more data is needed regarding the environmental concentration, fate and impact of these products to aquatic organisms, especially corals. Determining the risk of UV filters to coral reefs should be placed in context with other chemical contaminants also present in these ecosystems. Data in this session highlighted that a number of chemicals known to have an effect to corals were also detected in environmental monitoring programs. The risk to corals from individual chemicals and contaminant mixtures needs further identification and prioritization of the most harmful chemical contaminants. It is essential that academics, industry, government agencies and other stakeholders work together to increase the wealth of data available regarding the environmental concerns of UV filters. If toxicological effects are observed at environmentally relevant concentrations, then a UV filter may pose an unacceptable environmental risk, which then needs to be managed. We plan to continue the discussions from this session in 2019 at the SETAC Europe and North America annual meetings.
Lisa S. Ortego and Steven L. Levine, Bayer CropScience, and Joel Robert Coats, Iowa State University
The interest and use of biological materials in crop production is increasing globally at a rapid pace. Part of the interest is that these technologies are viewed as safer alternatives to conventional chemicals. The action of some of these materials is very pest specific; a great advantage for safety. While establishing the safety of these materials is as important as for conventional chemicals, there are important distinctions between them. For example, a rich literature base usually exists for many micro-organisms, which can be relied upon for important information and can reduce the amount of testing needed. Also, unlike conventional chemicals, micro-organisms must be evaluated for their pathogenic potential, not only in people but in ecological receptors, as well.
The United States was the first country to develop biopesticide-specific testing guidelines. Therefore, many countries look to the U.S. when developing regulations for biopesticides and microbials. Several countries have recently proposed or approved specific regulations for biological materials, including China, Brazil and Argentina. However, other regulatory authorities are making slow progress to develop a framework to address testing and risk assessment requirements for biopesticide and microbial products. In part, the reason for this is that some products can be technically challenging to test in ecotoxicity assays, and estimating environmental concentrations can be complex. Nonetheless, there are opportunities to harmonize current testing and assessment approaches so that safety requirements no longer vary greatly between jurisdictions.
We organized a biopesticide session for the SETAC North America 39th Annual Meeting. Presentations covered a variety of topics, including understanding soil and plant microbiota, U.S. and international regulations, considerations for when to develop testing and assessment strategies based on problem formulation, examples of testing and ecological assessment for specific products, challenges in regulatory testing and assessment, and recommendations for the future regulation of biopesticides.
There were eight platform presentations and two poster presentations. Following is a list of the presenters, titles and key messages from their presentations.
- Steven Bradbury (Iowa State University) – Future Products of Biotechnology and Needs for Risk Analysis Science: NAS Findings and Recommendations
- Bradbury summarized the forecast for biotechnology products and recommendations for regulatory governance and risk analysis based on the 2017 US National Academies of Sciences report.
- Johan Leveau (University of California, Davis) – Characterization and Manipulation of Crop Microbiota
- Leveau presented interactions of micro-organisms that colonize plants and soils, including how the interaction influences plant health, and quantity and quality of yield.
- Richard Garnett (CropLife International) – Global Survey of Microbial Pesticide Regulation and CLI’s Microbial Pesticide Safety Framework
- Garnett described the various regulatory requirements for biopesticides outside of the U.S. and presented the recommendations of CropLife International for biopesticide safety evaluations.
- Shannon Borges (USEPA) – Ecological Risk Assessment for Microbial Pesticides in the U.S.
- Borges reviewed the methods used for testing and assessment of microbial pesticides in the U.S., including an interesting discussion of some of the differences between chemical safety testing and microbial pesticide testing. The USEPA is involved with revision of the biopesticide testing guidelines and is working on this at the Organization for Economic Cooperation and Development (OECD).
- Joshua Fischer (Bayer) – Considerations for Ecological Testing and Assessment of dsRNA
- Unique attributes of dsRNA products, such as proposed use patterns, mode of action, activity spectrum and bioinformatics analysis, were used by Fischer to inform appropriate non-target organism testing, problem formulation and ecological risk assessment.
- Joel Coats (Iowa State University) – Dissipation of dsRNA in an Aqueous System
- Coats described an interesting study that suggested abiotic factors alone can facilitate the degradation of dsRNA in the environment. He concluded that dsRNA recovery was reduced to background by 96 hours post inoculation in aquatic systems with minimal movement to sediment.
- Henry Krueger (EAG Laboratories) – Challenges in Testing Biopesticides in Conventional Laboratory Ecotoxicology Studies
- Krueger discussed the challenges in biopesticides ecotoxicity testing, with a focus on the terrestrial requirements. His talk led to an interesting discussion of problems related to biopesticide toxicity testing in bees.
- Alison Fournier (Smithers-Viscient) – Safety Testing Strategies to Evaluate Biopesticides Used in Crop Protection on Aquatic Organisms
- Fournier presented an overview of the aquatic testing requirements, including identification of the test substance and necessary controls and modifications necessary for successful biopesticide testing.
There were also two posters included in the session.
- Anderson Abel de Souza Machado (Leibniz Institute of Freshwater Ecology and Inland Fisheries)– Current Environmental Regulations Might Not Protect Against Non-Targeted Effects of Microbial Pesticides: The Case of Dipel and Daphnia
- This poster described studies in Daphnia using Bacillus thuringiensis. De Souza Machado displayed non-monotonic chemical heterogeneity, which may have led to non-monotonic dose-response curves.
- Amber Tompsett-Higley (Bayer) – Environmental Safety Assessment for Agricultural Uses of Lipochitoligosaccharides as Plant Growth Regulators
- In this poster, Tompsett-Higley described a safety testing and assessment strategy for two lipochitoligosaccharide products.
Two key cross-cutting themes from the session were that the activity and characteristics of biopesticides are unique and that chemical testing and assessment methods are not applicable in many cases. Also, as the number of biopesticide-type products is expected to continue to increase, methods need to be thoughtfully re-evaluated and revised in order to address the specific nature of the materials.
The biopesticide topic is a new one for SETAC, and it was good to see a healthy level of interest. Attendance was above average for a SETAC session (range 49–85), which was driven by the quality of the presentations. We look forward to building on the interest in this session for future interactions at SETAC.
Marie DeLorenzo and Peter Key, NOAA National Centers for Coastal Ocean Science
Marine organisms in early life stages are especially vulnerable to contaminant exposure. They have greater capacity for chemical uptake due to higher surface area:volume ratios and faster metabolisms, and decreased capacity for chemical metabolism due to under-developed detoxification mechanisms. Moreover, the narrow windows of development in early life stages often leave marine organisms sensitive to contaminant disruption, which can lead to deformities. As marine and estuarine species develop and migrate across habitats, they deal with additional stressors, such as changes in salinity, pH, temperature, etc. Environmental toxicity testing with organisms in early life stages poses unique challenges and requires use of new methodologies to conduct these tests with these early life stage organisms. Topics covered in this session included mixture and multi-stressor toxicity, growth, development, and biomarker endpoints, novel exposures and novel test species. Fourteen presentations (eight platforms and six posters) discussed various attributes of working with organisms in early life stages, including the complexities inherent with use of early life stages and the necessity to use early life stages in contrast to using adult life stages to address difference in contaminant sensitivity of organism life stages. Presenters shared studies across five classes of contaminants using species from four animal phyla and six classes.
Kimberly Prince (University of Florida) examined polychlorinated biphenyls (PCB) concentrations in marsh sediment and the organisms living there. Her research found that mussels can biomagnify PCBs, leading to increases in PCB concentrations in surrounding sediment and a co-inhabitant, the marsh crab. This demonstrated how benthic invertebrate interactions could affect PCB integration into food webs. Kady Lyons (California State University, Long Beach) also presented on PCB toxicity but with the round stingray (Urobatis halleri). Little information is available on organic contaminant exposure or effects for elasmobranch species. Lyons noted a variety of negative impacts, including altered reproductive and osmoregulatory capacity in adults and decreased capacity for energy utilization in embryos.
Use of another novel toxicity test species, the glass eel (Anguilla anguilla), was presented by Catia Figueiredo (Marine and Environmental Sciences Center, Portugal). The compound studied was also less common, the rare earth element lanthanum, which is a contaminant of emerging concern due to its growing use in batteries. Figueiredo quantified bioaccumulation and observed sublethal effects on acetylcholinesterase activity, lipid peroxidation and antioxidant enzymes in juvenile eels at environmentally relevant concentrations. These results will inform further research with other rare earth elements and glass eels.
Two presentations provided new information on microplastics in the marine environment. Cheyenne Stienbarger (University of North Carolina-Wilmington) presented on the trophic transfer of microplastics from larval silversides to larval and juvenile black sea bass. Her research pointed to the need for examining trophic transfer to lend guidance to fishery management and concerns with human consumption. Dorothy Horn (Portland State University) examined the impacts of microfibers on reproduction and development of the Pacific mole crab. Ingesting this debris at environmentally relevant concentrations did alter development, which calls for further research. This was also a relatively novel test species.
Amy Ringwood (University of North Carolina-Charlotte) focused on biomarker responses in coral larvae. She determined that baseline levels of markers of oxidative stress in coral larvae serve as guidelines of sensitivity since little information exists for the larval forms. Larvae of a Hawaiian coral species were also exposed to several sunscreens to assess effects on reef repopulation, development and preservation. These new larval test methods will benefit coral research and conservation. Similarly, Paula Antunes (AquaTox Testing & Consulting) described a new test method with copepod embryos (Acartia tonsa). She discussed the development of a 48-hour embryonic marine copepod toxicity test. The initial testing aimed to assess the acute lethality of saline effluent discharged into marine or brackish environments from Canadian mining operations. Test development lasted two years, and Antunes shared its trials and tribulations, lending insight into the complexities of early life stage testing. Another new testing strategy, aimed at incorporating a marine copepod species indigenous to North America, was presented by Alan Kennedy (US Army Corps of Engineers – ERDC). The test species was the calanoid copepod Pseudodiaptomus pelagicus, and the method developed was a 48-hour acute exposure for sediment elutriate testing. Kennedy presented the initial results with sensitivity to copper, phenanthrene and ammonia.
With continuing interest in oil spill toxicity to early life stages, there were several presentations on various aspects of this topic. Two presentations from the National Marine Fisheries Service Northwest Fisheries Science Center (NWFSC) highlighted oil impacts to Pacific herring embryos. Julann Spromberg presented a population model tested for its ability to predict delayed mortality of herring stocks in Puget Sound. While the model showed limited ability to match observations in the field, it did indicate the intrinsic growth-rate tipping point for the population. Spromberg is conducting additional toxicity assessments with a focus on adverse outcome pathways to refine the model. Alysha Cypher presented some of these additional herring embryo exposures with Alaskan North Slope crude oil. She described the effects on larval cardiac abnormalities, bioenergetics and immune function. These results will be beneficial in determining delayed population impacts of oil spills. John Incardona (also from NWFSC) investigated impacts on Polar cod after embryonic exposure to Alaskan and Norwegian oil. Severe craniofacial malformations were found in hatched larvae from the higher exposures with significant long-term growth impairment in larvae from the lower exposure levels. Lipid levels were also reduced in exposed larvae, which could lead to reduced recruitment due to high overwintering juvenile mortality. Collectively, these studies point to potential for population-level effects in arctic species that are exposed to oil in early life stages.
Another study with fish embryos examined the multi-stressor effects of oil and hypoxia. Casey Lindberg (Duke University) presented on oxidative stress in zebrafish embryos. These embryos were exposed to a polycyclic aromatic hydrocarbon (PAH) mixture and low oxygen concentrations (hypoxia). While PAH alone induced activity of a stress biomarker (glutathione reductase enzyme), hypoxia alone did not. There were also no interactive effects on oxidative stress of PAH and hypoxia. Sechi Uno (Kagoshima University) also presented on a multi-stressor exposure with fish embryos. Uno offered new data on ultraviolet (UV) light-enhanced toxicity of PAHs in marine medaka embryos from sediment exposures. Specific oxygenated PAHs were found to cause cardiac arrhythmia and cardiac abnormalities. The use of very early embryonic stages for this testing can aid prediction of fish population effects. Peter Key (NOAA’s National Centers for Coastal Ocean Science) also presented research on UV light and oil interactions. He described results of 24-hour exposures to a thin oil sheen and UV light in grass shrimp larvae. The multi-stressor exposure reduced fecundity as the shrimp became sexually mature. The subsequent generational effects resulting from acute exposures of early life stages to thin oil sheens and UV light might lead to long-term impacts on grass shrimp populations.
The emerging themes from this session were the importance of using early life stages in toxicity testing to predict population impacts, the diversity of species and test methods being employed, and the growing interest in multi-stressor interactions. Estuarine ecosystems are an important nursery habitat that can be impacted by environmental and anthropogenic stressors, and this research serves as much needed background information. Some data gaps to be addressed with future investigations include refining early life stage testing methodology, incorporating adverse outcome pathways and following acute exposure effects on early life stages through development to evaluate chronic impacts.
John Parsons, University of Amsterdam, and Graham Whale, Shell
Biodegradation is a natural but still poorly understood process, whose outcome strongly depends not only on chemical structure but also on environmental conditions and the microbial diversity. A thorough understanding of the effects of these factors is required for a reliable assessment of the biodegradability and persistence of chemicals. The session was intended to present new developments in our understanding of biodegradation and to identify how existing test methods can be improved and new approaches be used to provide weight of evidence regarding the potential persistence of chemicals in the environment. The session strove to identify where there is need for further research in this area and explore how we can improve the assessment of the persistence properties of chemicals from both a societal and regulatory perspective.
The short session consisted of eight oral presentations and five posters, presenting work from both industry and academia.
- Kathleen McDonough (Procter & Gamble) started the session by discussing practical issues relating to using the OECD 301B test protocol to determine ready biodegradability of, for example, chemicals with low solubility and potential toxicity and chemicals that require adaptation of microbial populations to achieve ready biodegradation. A specific example was the effect of the physical form of polyhydroxyalkanoates on the kinetics of their biodegradation.
- Paul Tratnyek (Oregon Health & Science University) presented data on the biodegradation of 1,2,3-trichloropropane, a relatively poorly studied but highly toxic emerging contaminant that is widely used as intermediate and solvent. This chemical appears to be more persistent than many other chlorinated aliphatic hydrocarbons, and extreme conditions are required to achieve either biological or chemical degradation.
- Alistair Brown (University of Manitoba) presented new data on the behavior of pharmaceuticals and their human transformation products in wastewater treatment plants. The fate of these chemicals depends on operational parameters such as hydraulic retention time and suspended solids concentration. The transformation products are often present as conjugates, and they can undergo back-transformation during treatment.
- Yong Ran (Guangzhou Institute of Geochemistry) focused on chemical oxidation of benzo[a]pyrene using hydrogen peroxide and how it is affected by structure and properties of sediment organic matter. Their results indicate that aliphatic moieties and the stability and nanoporosity of organic matter have an important impact on the mineralisation of benzo[a]pyrene by H2O2
- Uta Hellmann-Blumberg (California EPA) described how transformation products of hydrocarbons can be addressed in the risk assessment of petroleum contaminated sites. For many contaminated sites, a better understanding of anaerobic biodegradation and transformation products is required in order to enable a comprehensive risk assessment.
- Graham Whale (Shell) presented on behalf of Amelie Ott (Newcastle University) the results of a study investigating improvements to the OECD 306 marine biodegradation screening test. The study focused on two potential improvements: increasing cell concentrations to better represent microbial biodiversity and extending the test duration to include extended lag phases. Implementing these improvements in a ring test involving 13 reference laboratories improved the reproducibility of testing outcomes for a set of reference chemicals, although some variability attributed to differences in microbial populations in different seawater samples were still observed.
- Baptiste Poursat (University of Amsterdam) presented the results of a study of the adaptation of microbial populations during long-term exposure to chemicals and the impact this has on the results of ready biodegradability tests. For some chemicals that fail these tests, long-term exposure results in enhanced biodegradation and reduced variability when using populations from different wastewater treatment plants. In some cases, however, extended exposure can lead to loss of the ability to degrade chemicals, indicating that a better understanding of population dynamics under these conditions is required.
- Finally, Graham Whale (Shell) gave a short summary of the objectives and outcomes of the CEFIC LRI-Concawe Workshop on Recent Developments in Science Supportive to the Biodegradation/Persistence Assessment held in September 2018 in Helsinki. This workshop was attended by many representatives of the regulatory community, who discussed the results of a number of recent and current projects. The objective of this workshop and the follow-up activities was to develop approaches to translate key knowledge from past and ongoing research into recommendations to improve regulatory assessment of persistence.
- In addition to the oral presentations, there were posters on the effect of petroleum hydrocarbons and of estrone and triclosan on soil microbial communities (Meijun Dong and Ezinne Osuji, Texas Tech University), the fate of emerging micropollutants and mercury in Capbreton Submarine Canyon sediment (Alyssa Azaroff, Université de Pau), the potential for lowering of the substrate concentration in the OECD 301B ready biodegradability test (David Riggs, Smithers Viscient) and the evaluation of PBT properties of surfactants (Pujeeta Chowdhary, Wood Environment & Infrastructure Solutions).
The research presented at the session makes it clear that while there are many shortcomings in our understanding of the factors that determine the rates and extent of degradation of chemicals in the environment, we are making progress, and there is a potential for improving the methods we use to assess biodegradability and persistence of chemicals. We hope that the SETAC community takes up this challenge.
Larry Kapustka, LK Consultancy, and David Ostrach, Ostrach Consulting, Session Co-Chairs
Sessions addressing multiple stressors have been a mainstay of SETAC North America annual meetings for more than a decade, and the topic continues to hold considerable interest. This year, the local connection was on exhibit through presentations that dealt with chemical and non-chemical stressors acting in the waterways of the California Bay-Delta.
Despite being the last day of the conference and competing with the adorable therapy dogs in the “Pup Rally” in the exhibit hall, attendance hovered between 80 to 90 people throughout the session. Those in attendance in the first half of the session were treated to excellent summaries of monitoring programs to manage chemical contaminants and nutrients. Tracey Collier of the Delta Independent Science Board focused on the need to use adaptive management in water quality programs, made 10 recommendations on areas of needed research, and discussed how these multiple stressors contribute to organismal and population declines in the Bay-Delta. This was followed by Shawn Acuña, Metropolitan Water District of Southern California, and his work on multiple stressors affecting delta smelt where findings suggested hepatotoxins, nutritional status as well as habitat type were adversely affecting reproductive status. The talk of Bethany DeCourten, University of North Carolina Wilmington, focused on effects of interactions of temperature and endocrine disrupting chemicals on estuarine fishes with results indicating adverse multi-generation effects of contaminant exposure. Marissa Giroux, University of California, Riverside, presented her work on exploration of the interactions of temperature and the fungicide bifenthrin on juvenile chinook salmon behavior and survival with results suggesting temperature was adversely affecting behavior with potential population level impacts. A break and the Pup Rally diminished attendance at the onset of the final presentations. However, uncharacteristically attendance increased during each of the last three talks of the afternoon, culminating with more than 90 in attendance for the last presentation of the meeting! The final presentations began with Marie DeLorenzo, NOAA National Ocean Service, discussing an interesting examination of the complex interactions of UV light, temperature and salinity on toxicity in estuarine species across multiple trophic levels. DeLorenzo’s results indicated that exposure to Louisiana Sweet Crude (LSC) oil and abiotic factors (e.g. UV light, temperature) increased organism sensitivity to the LSC adversely affecting survival. Peter Van Metre, U.S. Geological Survey, described the early results of an extensive monitoring program that is being conducting in the eastern United States representing agricultural and urban disturbance gradients. Preliminary results show marked differences in stream invertebrate fauna between areas that are predominantly in agricultural use versus urban settings. Mark Sandstrom, U.S. Geological Survey, presented preliminary results of a multi-stressor study measuring pesticides in 85 small streams in California. Insecticides were predicted to be important stressors to aquatic organisms in the streams sampled. Interestingly, greater insecticide uses in urban landscapes dominate the effects on the stream life. The session closed with a stimulating presentation by Wayne Landis, Western Washington University, in which he emphasized the use of tools, including Bayesian Networks capable of depicting causality, to achieve adaptive management of risks posed by multiple stressors.
Summaries Published in the February 2019 Issue
Guy Gilron, Borealis Environmental Consulting, and David DeForest, Windward Environmental
It’s now been several decades since the adverse effects of selenium on fish populations in Belews Lake, North Carolina, and bird populations at Kesterson Reservoir, California, were first documented. Since those early events, research on the fate and effects of selenium in aquatic environments has expanded substantially. The goal of this session was to summarize and highlight some of that research. The session was well attended, with presentations including retrospective evaluations of what has been learned, new research and regulatory challenges. Participants expressed interest through thoughtful questions and interactive discussion throughout the session.
Selenium effects on fish populations in Belews Lake and other early examples were observed in closed systems (e.g., reservoirs) receiving high selenium inputs. These events resulted in selenium toxicity studies with fish from the 1980s to the present, which have supported the development of fish tissue-based selenium guidelines and criteria in Canada and the United States. Guy Gilron, Borealis Environmental Consulting, presented a review of historical episodes of selenium affecting fish populations, which were associated with high selenium concentrations that were much greater than selenium toxicity thresholds. Based on this review, over the last two decades, selenium monitoring has identified water bodies in which selenium toxicity thresholds are sometimes exceeded, but without clear evidence of whether fish populations are being adversely affected. In many of these areas, fish population studies are often conducted, but studies are rarely published and often difficult to find. A primary outcome of Gilron’s presentation was a call for conducting and publishing fish population studies, which can support whether selenium guidelines or criteria are protective against population-impacts, and to facilitate information-sharing and support the development of future population studies.
Regarding the issue of impacts on fish populations, Bill Adams, Red Cap Consulting, provided a review of selenium effects on sturgeon, as well as the effects cadmium, copper and zinc had on the fish. Sturgeon are of particular interest for these elements because they are among the most sensitive species tested for selenium, copper and zinc, and some species and sub-populations are listed as threatened and endangered. Related to concerns of selenium and white sturgeon, Jennifer Sun, San Francisco Estuary Institute, presented a muscle-plug evaluation study conducted by the Regional Monitoring Program for Water Quality in San Francisco Bay. This study was developed in support of the North San Francisco Bay Selenium Total Maximum Daily Load (TMDL), which established a target benchmark of 11.3 µg/g dw in white sturgeon muscle tissue. The studies found that muscle plugs were good proxies for muscle fillets and identified sources of variability in selenium concentrations in white sturgeon, which is being used to design a long-term muscle plug monitoring program to assess trends and attainment of the TMDL target.
Three students from the University of Saskatchewan provided excellent presentations that continue to advance our understanding of selenium fate and effects in aquatic systems:
- Taylor Lane evaluated the maternal transfer of dietary selenomethionine (Se-Met), its effects on the F1 generation of fathead minnows (Pimephales promelas) and the use of embryo microinjection of Se-Met as an alternative method to simulate maternal transfer. Dietary Se-Met (highest dietary concentration was 29.58 µg/g dw) did not affect fecundity rates, hatchability or survival until swim-up. Deformity analysis revealed there was an increased frequency of deformities present with increasing selenium concentration in maternal transfer embryos and Se-Met-microinjected embryos; however, the microinjection exposure had more frequent deformities at lower doses suggesting different bioavailability between maternally transferred Se and microinjected Se-Met.
- Katherine Raes evaluated the bioconcentration of selenite and selenate by field-collected periphyton and trophic transfer to amphipods (Hyalella azteca). Selenite concentrations were found to increase in amphipods a dose-dependent manner, with trophic transfer factors (TTFs) ranging from 0.13 to 0.44 across all treatments. Conversely, selenate concentrations in amphipods fed selenium-exposed periphyton did not differ from control amphipods. This study highlights the importance of understanding selenium speciation in assessing selenium bioaccumulation in aquatic systems.
- Stephanie Graves conducted an in situ selenium bioaccumulation study in International Institute for Sustainable Development – Experimental Lakes Area (IISD-ELA) in northwestern Ontario. Selenite was dosed into littoral enclosures and total selenium concentrations were measured in water, sediment, benthic macroinvertebrates and female fathead minnows (promelas). Selenium enrichment factors ranged from about 7,400 to 12,000 L/kg dw and TTFs ranged from 0.6 for Gammaridae to 3.5 for Chironomidae overall treatments. The mean ovary selenium concentration in fathead minnows was 45.51 µg/g dw in the enclosure dosed with a selenite concentration of 9.58 µg/L, which exceeds regulatory guidelines and criteria. The study highlighted the increased bioaccumulation potential of a reduced selenium form (i.e., selenite) in a lentic system.
While the presentations summarized above focused on selenium fate and effects research, Sarah Skigen-Caird and Suzanne Pargee (GEI Consultants) gave a presentation on the regulatory challenges in implementing the U.S. Environmental Protection Agency’s fish tissue-based selenium criteria, finalized in 2016. Although the USEPA developed draft implementation guidance, the guidance has not yet been finalized and states have been hesitant to adopt the tissue-based criteria. They reviewed some of the issues and challenges arising from their discussions with state regulators and regional USEPA offices. These included fishless streams, underlying geology, resident species and a disconnect between water and tissue concentrations. Lessons learned and practical considerations for developing site-specific criteria were presented.
Lastly, Adrian deBruyn, Golder Associates, presented a study that evaluated the cause of increased selenium bioaccumulation downstream of a treatment plant that was reducing in-stream total selenium concentrations. Laboratory algal uptake tests were combined with field measurements of bioaccumulation, and selenium speciation analysis of treated effluent and receiving waters to develop a model of selenium bioaccumulation that explicitly accounts for speciation. The observed increase in bioaccumulation were quantitatively attributed to reduced species, including selenite, dimethylselenoxide and methylseleninic acid. A model was then developed to predict how bioaccumulation would be affected by a post-treatment oxidation step that returns effluent speciation to a selenate-dominated condition.
Overall, the session highlighted how much the understanding of selenium fate and effects has evolved over the last 40 years but also that important research continues. Although the importance of selenium speciation on bioaccumulation potential has been recognized for a long time, it is clear that more studies are focusing on how speciation affects bioaccumulation models, and this information is starting to be used to address real-world problems. In addition, although selenium regulations for aquatic systems have substantially progressed, it is clear that implementation of regulations which include both water- and fish tissue-based elements is still evolving and that site-specificity will always be an important consideration for evaluating the impacts of selenium.
Barnett Rattner, USGS – Patuxent Wildlife Research Center; Katrina Leigh, Ramboll; and John Elliott, Environment and Climate Change Canada
Wildlife ecotoxicology research and monitoring activities have long served to support conservation and regulatory decision-making. This session, organized by members of SETAC and The Wildlife Society, included eight platform presentations (with 50 to 120 attendees) and 10 posters that provided examples of how ecotoxicological data are useful for informed decision-making relevant to wildlife management or related regulatory actions at local, national and even global scales.
Mark Johnson, US Army Public Health Center, kicked off the session with a description of the status of wildlife ecotoxicology test protocols and knowledge, emphasizing the paucity of laboratory model species used in testing. This makes interspecific extrapolation challenging due to a myriad of toxicokinetic factors (e.g., exposure characteristics, gastrointestinal physiology, environmental weathering of compounds). The need to derive toxicity reference values for wildlife is paramount. Next, Phyllis Fuchsman, Ramboll, discussed the use of body weight scaling factors for chronic bioaccumulation studies of metals and polychlorinated biphenyls (PCBs). In the 1990s, some methods of scaling small animal acute toxicity studies produced implausible results for large animals, and it was concluded that without multispecies chronic toxicity data sets, such extrapolations should be dropped from risk assessments. However, some two decades later use of multispecies datasets from chronic bioaccumulation studies provided insight into such interspecific extrapolations. Using various exposure metrics (e.g., dietary exposure concentration, dose mg/kg body weight, mallard-equivalent doses determined by body weight scaling factors), it may now be appropriate to reconsider the current practice of toxicity extrapolations among species on a dose basis without accounting for differences in body weight. Brad Sample, Ecological Risk, Inc., then presented results of field studies that guide management of molybdenum exposure of mule deer and elk at a mining site in New Mexico. Diet composition of deer and elk grazing at tailing facilities was determined using plant chloroplast DNA in scat samples. Using molybdenum bioaccumulation factors for 17 species of plants commonly consumed by these herbivores, six plants (rubber rabbitbrush, blue grama, bottlebrush squirreltail, big sagebrush, western wheatgrass and common sunflower) were identified for a re-vegetation seeding mix that would minimize exposure and risk to these large grazing mammals. A provocative presentation by Larry Tannenbaum, US Army Public Health Center, followed, describing the importance of site fidelity when selecting mammals as receptors of concern for ecological risk assessments. Based on state-of-the-art GPS tracking data with gray fox, paralleling previous work with the white-tailed deer, the worthiness of larger mammal inclusion for typically small Superfund-type sites was challenged. Audience debate followed, with conclusions suggesting that, for various reasons (e.g., lack of site fidelity, large home range), it could be that for sites small in size, no mammals are appropriate when undertaking risk assessments.
Modeling impacts of chemical mixtures across landscapes is challenging due to spatial heterogeneity and complexity of sources, pathways and fate of multiple contaminants in the mixture. Using geographic information systems (GIS) and associated techniques, Kristin Eccles, University of Ottawa, and coworkers evaluated 1,100 samples from five biomonitoring projects of the Athabasca Oil Sands area in Canada in a spatial ecological risk assessment. Results from this study support the use of GIS to integrate data and assess complex exposures and dose-response relationships. Observed patterns of contaminants in the oil sands region demonstrate an increase in metal exposure in wildlife located around the upgrader region when compared with samples from other regions. Myra Finkelstein, University of California, Santa Cruz, then presented extensive stable isotope data demonstrating that ingestion of spent lead ammunition from feeding on terrestrial mammal carcasses is the principal source of lead in free-ranging California condors, while feeding on marine mammals is a significant source of p,p’-DDE. Lead poisoning is the primary threat preventing condor recovery in the wild. Population viability and management models were used to quantify the effects of contaminant exposure and guide management actions that foster population growth of the condor. These analyses led the State of California legislature to enact regulations banning the use of lead ammunition for hunting in California (effective 2019), and also to prioritize the use of other management resources to enhance condor population growth, principally through release of captive-bred condors. Stella McMillin, California Department of Fish and Wildlife, next described long-term state monitoring for anticoagulant rodenticides in wildlife. Interpretation of data has been challenging. While some samples (mountain lion, San Joaquin kit fox, fisher) have been collected through rigorous scientific activities other samples have inherent biases (e.g., carcasses from rehabilitation centers near human population centers). Difference in species sensitivity and variation in residue reporting limits have complicated the interpretation of findings. Despite 2014 regulations restricting use of the more toxic second-generation anticoagulant rodenticides, cases of intoxication from these compounds have continued to be detected. The closing presentation from Carolyn Marn, US Fish and Wildlife Service, reviewed the process of Natural Resource Damage Assessment undertaken in response to release of hazardous substances and the discharge of oil into navigable waters, and the requirements and challenges that must be met to seek compensation from responsible parties to restore injured wildlife.
Ten poster presentations accompanied the platform session on a variety of topics, some of which focused on use of wildlife toxicology data to support management decisions. These included new test data that could support the establishment of an early life stage avian toxicity test, use of immune function measurements in colonial waterbirds to rank areas of concern in the Great Lakes, and development of toxicity reference values for selenium in birds that incorporate trophic transfer factors, which may be more robust in predicting effects in free-ranging birds.
Clearly, this session covered myriad topics and examples of how the science of ecotoxicology has supported risk assessment and remediation activities at the local, national and international levels. Presentations were informative and intellectually stimulating to students and young professionals and also to well-established scientists and risk assessors.
Michael Anderson and Regina Donohoe, California Department of Fish and Wildlife, Office of Spill Prevention and Response
Three years ago, an oil pipeline ruptured adjacent to Refugio State Beach, Santa Barbara, California, and more than 120,000 gallons of crude oil flowed down a drainage ditch into the Pacific Ocean. In the hours, days, weeks, months and years following the spill, natural resource experts conducted studies to shed light on the short- and long-term effects of the spill on this scenic stretch of coastline, using a process known as Natural Resource Damage Assessment (NRDA). In this session, scientists from the California Department of Fish and Wildlife, Office of Spill Prevention and Response (CDFW-OSPR); National Oceanic and Atmospheric Administration, Office of Response and Restoration (NOAA-ORR); and U.S. Fish and Wildlife Service (USFWS) summarized key NRDA findings in eight platform and three poster presentations.
The Santa Barbara Channel has unique ocean currents and natural oil seeps that release oil from the seafloor. Michael Anderson, CDFW-OSPR, presented how NOAA trajectory models predicted the spilled oil would move down the southern California coast to Los Angeles, which was verified by oiling observations along the shoreline. Through careful chemical analyses, Greg Baker, NOAA, detailed how tiered forensic techniques distinguished the spilled oil from natural seeps in samples of stranded tar balls, floating oil and sandy beach invertebrate tissues. Oil exposure was quantified in a variety of media. On sandy beaches, polycylic aromatic hydrocarbons (PAHs) in sand crab (Emerita analoga), polychaete (Thoracophelia spp.) and talitrid (Megalorchestia spp.) tissues and beach porewater were elevated following the spill, declining with distance away from the spill and over time, consistent with oiling observations. In surfperch (Embiotocidae), biliary PAH metabolite levels were elevated at Refugio State Beach, compared with less oiled and natural seep areas, providing evidence of oil exposure in the nearshore environment.
Bruce Joab, CDFW-OSPR, reported on talitrid population monitoring data which indicated oil exposure was associated with declines in abundance of this important wrack-feeding amphipod. In the intertidal and subtidal habitats, discolored surfgrass (Phyllospadix torreyi) and algae were observed near the spill site. Natalie Cosentino-Manning, NOAA-ORR, described quantitative field survey results that related the degree of discoloration to the level of nearshore oiling in this productive habitat.
Dead fish, invertebrates and birds washed onto beaches adjacent to the release point immediately after the spill. To understand effects on fish and invertebrate early life stages, sand crab megalopae, inland silverside (Menidia beryllina) larvae, and blue mussel (Mytilus spp.) larvae bioassays were conducted by exposing the organisms to dilutions of a high-energy, water-accommodated fraction of the spilled oil. Bryand Duke, CDFW-OSPR, and Stephen Clark, Pacific EcoRisk, concluded sand crabs were the most sensitive organism tested, followed by the inland silverside, with six- to seven-day lethal concentrations to 50% of the test organisms (LC50) ranging from 41 to 76 µg total PAHs/liter. Regina Donohoe, CDFW-OSPR, presented surf water and porewater chemistry data which indicated water concentrations after the spill exceeded lethal levels for early life stages. Similarly, Laurie Sullivan, NOAA-ORR, summarized how grunion (Leuresthes tenuis) eggs collected from beaches that were exposed to oil had lower hatch rates in the laboratory, compared with baseline levels. For birds, a plausible connection between oil ingestion via preening and feeding and the increase in egg infertility in Western Snowy Plovers (Charadrius nivosus nivosus) at Coal Oil Point Reserve was demonstrated by Jenny Marek (USFWS). Additional assessments were conducted to determine whether marine mammal strandings were likely spill-related.
Overall, more than 50 studies were conducted to quantify injuries to wildlife, habitat and lost human uses for these resources. Through the NRDA process, restoration projects will be identified to both restore and compensate for these losses. Assessment results and proposed restoration projects will be provided in the Draft Refugio Beach Oil Spill Damage Assessment and Restoration Plan anticipated for release in 2019 at www.wildlife.ca.gov/OSPR/NRDA/Refugio.
Steve Bay, Southern California Coastal Water Research Project; W. Tyler Mehler, University of Alberta; Tamara Sorell, Brown and Caldwell; Lisa Nowell, US Geological Survey; Jay Gan, University of California, Riverside; and Jing You, Jinan University
Sediment continues to be a key medium to evaluate aquatic risk of environmental contamination. Tools to evaluate sediments have continually been refined and developed and now are addressing complicated issues including bioavailability, mixture toxicity and causal assessment. This session included descriptions of new tools for assessing bioavailability and causation, as well as refinements to existing tools, and examples of their application in the field.
The first four presentations were dedicated to understanding some of the complexity of sediment contamination assessment, namely bioavailability and toxicity endpoint choice. After the coffee break, the subsequent platforms discussed novel tools for causal assessment and described applications of some of these tools in monitoring programs.
Key messages from the presentations included:
- The use of passive sampling and other methods to assess bioavailability or bioaccessibility of trace organics in sediment continues to expand. The use of solid phase microextraction (SPME) to monitor contaminant flux through a sediment cap was presented by Jacob Williams, US Army Corps of Engineers. Jay Gan, University of California, Riverside, described the use of TENAX desorption to investigate the effects of sediment aging on contaminant bioaccessibility and bioaccumulation.
- Application of laboratory exposures using aquatic macroinvertebrates to assess contaminant bioavailability and impacts were described in two presentations. Isabelle Proulx, GHD, described the use of different species of Chironomus (each having different feeding modes) to examine changes in metal bioavailability in oxic vs. anoxic sediments. Progress in refining the use of sediment avoidance endpoints in toxicity testing was presented by Roger Yeardley, US Environmental Protection Agency. These tests have the potential for increased sensitivity compared with standard endpoints, but more development and consideration of other behavioral responses is needed to improve interpretation of the results.
- Advances in methods for Toxicity Identification Evaluation (TIE) and causal assessment were described in several presentations. Refinement of an in-situ TIE system to characterize toxicants in sediment porewater was described by Allen Burton, University of Michigan; improvements include addition of an electronic controller to increase reliability. The combination of TIE with effect-directed analysis (EDA) to diagnose the cause of sediment toxicity was described by Jing You, Jinan University. Toxicity of EDA fractions were evaluated using a novel high-throughput test method with Chironomus. David Gillett, Southern California Coastal Water Research Project, described progress in developing a screening-level causal assessment approach for benthic macroinvertebrates. A key step in the framework is the development of comparator sites to control for the effects of confounding habitat factors.
- The closing talk of the session by Bryn Phillips, University of California, Davis, presented a synthesis of 10 years of chemistry and sediment toxicity monitoring in California’s Stream Pollution Trends Program (SPoT). The SPoT monitoring program has documented temporal changes in contaminant distributions and toxicity and continues to evolve to include new methods and address contaminants of emerging concern.
This session was supported by the Sediment Interest Group (SEDIG), and we encourage those interested in the topics summarized here to join the SEDIG community online.
Valery E. Forbes, University of Minnesota; Ismael Rodea-Palomares, Bayer Crop Sciences N.A.; Amelie Schmolke, Waterborne Environmental; and Nika Galic, Syngenta Crop Protection, LLC
Chemical fate models are fundamental tools for understanding and forecasting the behavior of chemicals in the environment and potential exposures to them. Biological and ecological effect models are essential to understand potential environmental impacts of chemicals on individuals, populations and ecosystems. Both families of models can function as powerful tools for risk assessment, and their integration is particularly beneficial for higher-tier environmental risk assessment (ERA). Higher-tier refinements typically include assessing risks to non-test species, across large spatial and/or temporal scales and multiple exposure scenarios. All of these are too difficult to test empirically, due to logistical or ethical reasons. Modeling approaches are able to bypass these difficulties and integrate important information at appropriate scales for a more comprehensive and environmentally relevant risk assessment. Notwithstanding their usefulness, there are still challenges for the development and integration of fate and effect models including technical, practical, conceptual and communication challenges across modeling communities and users. A lack of guidance on model development and implementation, a lack of data for model parameterization, and a lack of case studies to demonstrate proof of concept are frequent reasons given for models not being used or accepted.
This session focused on recent advances in environmental fate and effect modeling related to model parameterization, robustness, consistency and transparency. The first part of the session showed how integrated fate and effect models can improve the understanding of risks associated with pesticides. Rafael Muñoz-Carpena, University of Florida, demonstrated how global sensitivity and uncertainty analyses (GSUA) can provide a powerful and flexible framework to identify important factors driving model sensitivity when a multitude of factors interact together to affect model output. He illustrated the use of GSUA to guide model parametrization and development for pesticide run-off modeling. In particular, he presented a series of case studies emphasizing how features of realistic field conditions, such us concentrated flow or the presence of a shallow water table, could influence the effectiveness of vegetative filter strips in reducing pesticide runoff and inform pesticide run-off mitigation strategies. In related work, Ismael M. Rodea-Palomares, University of Florida, currently at Bayer CropScience, showed how current regulatory higher-tier exposure models (PWC shell) could be linked with a mechanistic aquatic effect model (AQUATOX) to evaluate the efficacy of vegetative filter strips in reducing the long-term risk and effects of pesticide runoff to aquatic organisms. The work demonstrated the challenges involved in integrating the models and highlighted the nonlinear relationships between reductions in exposure and magnitude of effects for different vegetative filter lengths. An important take-home message is that integrated models which can deal with such complexity can greatly facilitate the assessment of risk.
Matthew Etterson, US Environmental Protection Agency, continued the theme of model sensitivity analysis and pesticide risk assessment by exploring the relative importance of three model parameter categories – life history, exposure, toxicity – in an integrated avian fate and effects model (TIM-MCnest). In the absence of exposure, avian reproductive output was most sensitive to mortality (egg, nestling and adult) across all metrics. However, with exposure, different sensitivity metrics conveyed different information about the consequences of perturbations of model parameters. These were not necessarily correlated with each other, implying that great care is needed when choosing such metrics.
One important task for which modeling is ideal is providing information to help guide where the appropriate spatial and temporal scale focus should be that are relevant for the risk assessment being conducted. Wenlin Chen, Syngenta Crop Protection, LLC, evaluated two watershed modeling approaches for their ability to predict aquatic pesticide exposure concentrations. One model was process based (PRZM-SWAT), whereas the other was based on a time-series regression (SEAWAVE-QEX). Outputs of both models were compared with high sampling frequency (near daily) monitoring data and shown to have somewhat different predictive capabilities and limitations. As a process-based model, PRZM-SWAT may be used for long-term forecast of potential exposures. On a retrospective basis, SEAWAVE-QEX is more useful for estimating potential exposures that might be missed in monitoring programs with sampling intervals larger than daily. Results of the presentation also highlighted the importance of data-informed modeling to improve model predictability of different magnitudes.
The second part of the session featured mechanistic effect models, demonstrating their value in extrapolating from toxic effects of chemicals on individuals to consequences for populations. Jill Awkerman, US Environmental Protection Agency, presented a systematic framework for population model development applied to anuran amphibians. The value of such a framework is to add consistency and provide guidance on model development while allowing flexibility to adapt models for specific risk assessment needs. Chiara Accolla, University of Minnesota, used an individual-based model of three trout species (Oncorhynchus mykiss, O. clarkia stomias and Salmo trutta) to show how the same degree of chemical impact at the individual level can have different consequences at the population level, even for closely related species. In this case study, differences in fecundity and mortality rates appear to be important contributors to the observed species-specific differences in population dynamics. Maxime Vaugeois, University of Minnesota, explored the effects of hypothetical stressors, simulated to impact different aspects of fathead minnow (Pimephales promelas) energy budgets, on minnow population dynamics. Not only did the population-level consequences vary depending on which individual-level response was impacted, but they varied markedly between populations limited by food (i.e., those under density-dependent control) and those controlled by predators (i.e., those under density-independent regulation). Amelie Schmolke, Waterborne Environmental, linked an individual-based model of the Topeka shiner (Notropis topeka) with an aquatic food web model (CASM) to explore potential direct and indirect effects of pesticides on this endangered species. This is a particularly important application of population modeling given the requirement that potential direct and indirect pesticide risks to all species listed as threatened or endangered under the Endangered Species Act need to be assessed, and population modeling has been recommended as a tool with which to do so.
By addressing one or more of the key concerns believed to impede the use of models in ERA, all of the presentations in this session contributed to increasing model implementation in the future. Individually and collectively, they provided guidance on model development and use, they presented concrete case studies showing how integrated fate-effect modeling can quantify risks in complex and realistic systems, and they demonstrated a wide variety of strategies for model parameterization and analysis. Presentations in this session demonstrated the importance that fate and effect modeling has reached as ERA tools in the last couple of decades, and emphasized ongoing progress by introducing new tools and strategies to help improve model development, analysis and applicability, as well as understanding and credibility.