Summaries Published in the February 2020 Issue
Jake Martin, Monash University; Erin McCallum and Tomas Brodin, Swedish University of Agricultural Sciences
On the third day of SETAC Toronto, if you stopped by Room 718A, you would have seen a crowd of academics, government and industry scientists captivated by talks on the impacts of chemical contaminants on animal behavior. Our session was inspired by the ever-increasing use of animal behavior as a sensitive endpoint to measure the adverse and often sublethal effects of environmental pollutants. In our session, we focused on ‘incorporating environmental complexity and relevance’ and were eager to hear from scientists who have pushed the boundaries of this field by incorporating the complexities of natural conditions. We had two objectives for our session. First, during the platform presentations, we wanted to showcase new findings, focusing on research that included higher levels of environmental complexity. Second, we led a panel discussion with leaders in the field to address the current challenges and criticisms that face the new and growing field of behavioral ecotoxicology.
The platform presentations were well received, with over 100 delegates at one stage. An outstanding group of researchers from a wide variety of career stages delivered these presentations, namely Anoosha Attaran, Apolline Chabenat, Hossein Mehdi, Alexandra Steele, Paul Blanchfield, Mirco Bundschuh and Bob Wong.
Attaran opened the session with a compelling talk about the impacts of selenium on social learning and information transfer in fish, reporting that selenium exposure can reduce the efficiency social learning in fish. More generally, Attaran’s work highlighted that social learning is an overlooked but important aspect of animal behavior in regard to chemical pollution. Chabenat followed with an exiting talk on the impacts of antidepressant mixtures on the burying behavior of shore crabs and cuttlefish. Chabenat reported that for both species, burying behavior was modified by the antidepressant ‘cocktail’ (specifically, fluoxetine and venlafaxine) at environmentally realistic concentrations, with likely consequences for individual survival. Mehdi’s research took us one step closer to the field, by showing that fathead minnows exposed to municipal wastewater effluents had higher metabolic rates and behaved less boldly—but only during exposures in the summer and not the winter. His work highlights the need to account for how seasonality may dampen or exacerbate the effects of environmental stressors. Next up, Steele presented her work on the behavioral impacts of per- and poly-fluorinated alkyl substances (PFAS) on wild crayfish living in contaminated ecosystems. Steele showcased the benefits of crayfish as a model organism for behavioral ecotoxicological monitoring, while also reporting the potential impacts of PFAS on antipredator behavior of crayfish across field sites of varying levels of contamination.
After the break, the crowd returned, eager to learn more about behavioral ecotoxicology. Blanchfield started us off by presenting new findings from the landmark Experimental Lakes Area whole-lake exposure with ethynilestradiol. He showed (with videos too!) that the few male fish left defending nests in the exposed lake were bombarded with aggressive females, perhaps disrupting their ability to raise their offspring. This will certainly be an interesting addition to this already important whole-ecosystem study. Next up, Bundschuh delivered an interesting conceptual note about measuring the effects of pollution across ecosystem boundaries. He highlighted some of his group’s current work tracking pollution transfer from aquatic to terrestrial environments using replicated large-scale artificial streams. To close the platform presentations, Wong gave a captivating overview of the benefits and importance of animal behaviur in ecotoxicology. Explaining how, as a behavioural and evolutionary ecologist, he was drawn to the field of ecotoxicology. He gave a summary of his years of work studying the behavioral impacts of the hormonal growth promotant (Trenbolone) on fish behavior.
We wrapped up our session by holding an open panel discussion comprising Bryan Brooks, Paul Blanchfield and Bob Wong. The panel explored key topics including the use and standardization of behavioral endpoints for legislation, and if we can predict the ecological and evolutionary impacts of behavioral disruption for wild populations. A crowd of over 50 delegates stayed to listen and many participated in the conversation about the future of the field. The panel even ran well into the coffee break, with many delegates sacrificing the strong need for coffee to continue the discussion.
Overall, lots of new and exciting behavioral science was presented and discussed during the session, and also on the wonderful posters that accompanied the platform presentations. The interest in this field is certainly growing and it will be exciting to see how it develops until the next SETAC meeting.
Ralph G. Stahl, Jr., Dupont (retired) and Phil Dorn, PB Dorn Associates
The SETAC North America Senior Resource Group (SRG) helped to sponsor two sessions at the SETAC North America 39th Annual Meeting, one of which was a Special Forum called “Oh, The Changes I’ve Seen Over the Past 30 Years.” This was a new session format for SETAC called “storytelling.”
There were nine speakers who spoke about how their careers started and evolved, and the role that SETAC played. It began with Gary Ankley, USEPA, who discussed a career that has spanned sediment toxicology, endocrine disruption and now mechanistic toxicology including development of the adverse outcome pathway framework. Ankley was followed by Scott Belanger, P&G, who showed how his research focus spanned various types of mesocosms, both in the field and laboratory, and noted the importance of connecting the results from both types. Ceil Mancini, AECOM, described her love of the sea that began as a young girl and continues today. A benthic biologist by training, she noted that a major challenge getting into the field at her first job was finding a pair of chest waders that fit her. Ron Kendall described how wildlife toxicology was a very small field when he began his career more than 30 years ago, but now has become a major focus area of SETAC and other groups. Teresa Norberg King, USEPA, gave an excellent overview of how whole effluent toxicity testing went from an “experiment” to a test that is widely used by regulatory agencies. Ellen Mihaich, private consultant, discussed being a “endocrine disruptor groupie,” and in doing so showed how the early reports of disruption in marine welks has evolved into national and international efforts to understand how various chemicals cause harm to invertebrates and vertebrates alike. Pieter Booth, Ramboll, discussed the evolution of ecosystem services from a theoretical consideration to a process to estimate the natural resource value of specific habitats or ecological processes. Annette Guiseppi-Elie, USEPA, gave an interesting overview of how exposure science has evolved over time, and where today it is a much more integral component in the estimation of risk to human health and the environment. Finally, our last speaker, Will Gala, Chevron, provided his view that ecological risk assessment should be used only in specific situations, not wholesale, for evaluating contaminated habitats.
All in all, these nine presenters covered a lot of ground in the morning session, often to a standing-room only crowd, and in a timeframe designed for eight speakers instead of nine.
Summaries Published in the January 2020 Issue
Matthew Lambert, U.S. Environmental Protection Agency and Bonnie Brooks, Minnesota Pollution Control Agency
Soil background is important to consider when making risk assessment decisions for cleanup or disposal of contaminated soil. Too often, soil background is either not used at all or used inappropriately when making important decisions. This session offered about 70 audience members some insight into how soil background has been effectively used in risk assessment.
Soil screening values are used to evaluate whether contaminants pose risks to people or the environment. Since they are intended to be protective of people or ecological species, they are derived using toxicity data, exposure parameters and contaminant specific parameters, but they don’t account for the amount of a contaminant present in soil due to background. In some cases, soil screening values for a contaminant are below soil background. When background concentrations are similar to or above soil screening levels, it is important understand the contribution from soil background and include this in risk assessment.
Topics covered included natural and ambient soil background studies already performed, how data from studies have been used to establish both natural and ambient soil background values, important items to consider when using these studies and when deriving soil background values, and how soil background has been used in risk assessment.
Natural background of metals in soil, with a special emphasis on arsenic, was the subject of the first half of the session.
- Bonnie Brooks, with the Minnesota Pollution Control Agency and session co-chair, discussed how they re-analyzed some of the U.S. Geological Survey (USGS) soil samples, including arsenic among other metals, using the U.S. Environmental Protection Agency’s (USEPA) analytical method to use that data to determine soil background. Many audience members were surprised to learn that results from the two analytical methods differed.
- Leah Leon, from Canada North Environmental Services, discussed how they developed an approach to determine soil background in areas of Canada where higher concentrations of metals are present due to natural geologic conditions. Emphasizing arsenic, Leah also discussed how they handled soil background in surrounding areas that did not contain elevated background concentrations.
- Christine Peterson of EHS Support compared two methods for determining potential risks from soil background using four reference sites. In some cases, they found risks were elevated based on soil background alone, without consideration for anthropogenic sources.
- Damon Delistraty, from Washington State Department of Ecology, compared state-wide and local soil background concentrations of arsenic to human and ecological soil values. Delistraty discussed this in context of a policy used for arsenic at the United States Department of Energy Hanford Site located in Washington.
Ambient soil background was the subject of the second half of the session, which included discussions regarding both metals and organics.
- Sydney Chan, with the USEPA, explained how they completed an ambient soil background study of metals and polycyclic aromatic hydrocarbons (PAHs) in eight cities in the southeastern United States. Audience members were excited to hear that their long-awaited dataset would be posted on USEPA’s website soon.
- Matt Lambert, also with the USEPA, discussed how they reviewed dioxin, furans and polychlorinated biphenyl (PCB) soil background studies conducted at Superfund sites. They looked at how this information was used in risk assessment and management decisions.
- Casy Fath from Barr Engineering discussed ambient soil background for per- and polyfluoroalkyl substances (PFAS). Fath also talked about how they have been keeping track of how different regulatory agencies require PFAS in soil to be evaluated.
- Kanan Patel-Coleman of AECOM discussed how they developed a model to quantify the contribution of forest fires to ambient PAH soil background in California. Most interesting was the finding that PAHs from forest fires did not contribute significantly to ambient PAH concentrations.
Take home messages:
- Consideration for both natural and ambient soil background in risk assessment is important.
- Data from existing soil background studies may be suitable to use to establish soil background without going through the effort of conducting a soil background study.
- Results differ between the USGS and the USEPA analytical methods for metals in soil.
- Geological conditions present in an area may lead to elevated natural background concentrations in that specific area, which may differ significantly from surrounding areas.
- Urban areas may also present areas of elevated concentrations that may not be attributable to a release, presenting technical and policy challenges.
- Risks to people or ecological species may be present from naturally occurring metals in soil.
- There is no widely accepted standard approach for incorporating background into risk assessment.
- Naturally occurring fires are likely not a significant source of ambient polycyclic aromatic hydrocarbon concentrations in soil.
Author’s contact information: Lambert.Matthew@epa.gov
Carolyn B. Meyer, Arcadis, Inc.; Katherine E. Horak, U.S. Department of Agriculture; and Barnett A. Rattner, U.S. Geological Survey
The pressures to control invasive and pest vertebrates to meet societal goals and yet protect wildlife is becoming increasingly challenging. This session, including eight platform presentations and two posters, discussed recent advances in assessment of risks to non-target species of control practices and tools used to control invasive wildlife using more species-specific and/or safer toxicants, contraceptives and gene editing.
The session addressed four themes: anticoagulant rodenticide (AR) research, genetic technologies, population modeling, and risk assessment and mitigation. John Elliott, Environment and Climate Change Canada, kicked off the AR presentations with an analysis of the current incidence of wildlife exposure to ARs in various countries. For raptors in western Canada, second generation AR poisoning accounted for up to 7% of reported deaths, 33% of expected deaths based on lethal hepatic thresholds, and up to 60% of raptors may have sublethal injury (increased clotting time). Barnett Rattner showed wildlife exposure to second generation ARs in the U.S. continues despite recent risk mitigation measures that include restricting second generation AR use, packaging size, and types of bait and bait stations. Richard Poche, Genesis Labs, promoted the less persistent first generation ARs as a viable alternative to other rodenticides. He discussed misconceptions about resistance to and effectiveness of first generation ARs, importance of antidote availability, and correct dosage as safety measures. Virginie Lattard, VetAgro-Sup in France, presented her results from modifying the proportion of different stereoisomers in second generation AR baits to obtain a new efficient generation of anticoalgulants that have a reduced half-life in rats, reducing exposure risk of non-target species.
For genetic technologies, Katherine Horak explained gene drive, how it can be used to change inheritance probability, and how gene silencing can cause species-specific mortality. Both are promising new tools for pest control that theoretically will not harm non-target species. To use these technologies requires understanding where to apply them most effectively. Richard Erickson, USGS, used spatially-explicit population modeling to decide where to control invasive Asian carp. His goal was to prevent spread of bighead and silver carp by identifying where to target controls, apply deterrents and collect better data. He incorporated pool-specific life history and movement data in the model to predict specific pools to target with various controls such as RNA interference, toxic species-specific microparticles or synthetic biology (re-program an organism to produce toxic substance). Carolyn Meyer also discussed population modeling as a tool useful for predicting rates of pest population recovery after rodenticide application and for assessing secondary poisoning risk by quantifying effects on the population size of non-target species. Chiara Accolla, University of Minnesota, used population modeling to address impacts of invasive species on threatened species. Accolla illustrated how the brown trout can reduce and extirpate threatened greenback cutthroat trout populations as well as exacerbate chemical (estrogen) impacts. She pointed out that such models can explore potential consequences of invasive species control measures on the fish community.
While many of these presentations touched on application of the various tools for use in risk assessment or mitigation, Karl Campbell with Island Conservation fully explored a real-world example of assessing and managing risk associated with invasive rodent eradications on islands using anticoagulants in his presentation. Invasive rodents cause 30% of all extinctions; to-date there have been 640 eradications of invasive rodents on islands using rodenticides. Risk from secondary poisoning to wildlife, livestock and humans is assessed against conservation benefits using food web analyses, evolutionarily significant units, prioritization of exposure pathways and population viability assessments. If risk is unacceptable, mitigation options including captive holding are identified and implemented. Support of the island community has been critical for the success of this process. Philippe Berny, Vetagro-Sup, closed the session with a presentation on recent advances in risk assessment and monitoring of rodenticides in Europe. Non-target arthropods and toxicokinetic/toxicodynamic models are being considered for aquatic risk assessments. For terrestrial risk assessments, a broadening of scope to include amphibians, reptiles or bats is being considered. These presentations from scientists in academia, government and industry provided a balanced perspective on the challenges and possible solutions for safer vertebrate pest control.
Hans Sanderson, Aarhus University; Scott Belanger, Procter & Gamble; Dimitri P. Abrahamsson, University of California; and Dorte Herzke, Norwegian Institute for Air Research
The focus of the session was large polymeric substances, rubbers and macroplastics in environmental risk assessment. The classical view that endpoints used to quantify organism stress are a result of biological uptake into tissues is now clearly expanding to include effects (both internal and external) resulting from physical interaction with the organism. Physical effects have been traditionally disregarded as less toxicologically relevant and outside the traditional theorem of dose-dependence by Paracelsus for ascribing acute and chronic toxicity to chemical exposure, and they are now also relevant for consideration in environmental assessment. Until recently, polymers and macroplastics have been exempt in most regulatory programs but this is now being revisited. Analytical methods for detection of presence, evaluation of exposures in laboratory studies, and methods to confirm environmental exposure models are challenging for many functionalized and sorptive materials among these polymers, rubbers in synthetic turf and macroplastics. In this session and for the first time, we sought to unfold the state-of-the-science of the challenges polymers represent for analytical chemistry, ecotoxicology, fate and exposure in the aquatic environment and to discuss what these challenges mean in a regulatory context.
A high interest for the session was expressed through the presentations, questions and answers at the platform session among the more than 130 participants, with standing room only for the entire session and the discussions at the poster session. In addition, a World-Café style workshop was held during the lunch break the following day, with a focus on the analytical challenges facing polymers attracting an additional 25+ participants with a broad geographical and sectorial spread.
We had platform and posters presentations from North America, Europe, Africa and Asia, covering academia, business and government. The session covered views from different experts and stakeholders from the Joint Research Centre (JRC), an EU Member state, industry and the European Food Safety Authority (EFSA) followed by an interactive plenary discussion.
The session covered the following key points:
- Hans Sanderson, Aarhus University, introduced the session and set the scene by providing an overview of the science regarding aquatic toxicity of polymers and the challenges with regards to risk assessment.
- Monica Lam and Yiping Sun, P&G, presented first the analytical challenges but also emerging methods to quantify polymers in aquatic samples in support of toxicity testing.
- The aquatic toxicity of cationic polyquateriums was reviewed and presented by Jessica Brill, P&G, and Anna Brun, Aarhus University, who showed the challenges with the standard tests when testing sorptive materials.
- We had a concrete case study from a cationic biocide polymer in regard to assessing the environmental risk in a regulatory process presented by Daniel Cros, Pareva, and Cyril Durou, Cehtra, and showed the challenges they faced in this process.
- Hlengilizwe Nyoni, University of South Africa, presented pyrolysis-gas chromatography mass spec methods they apply to quantify microplastics in water samples in an African context.
- Zoei Diana, Duke University, presented short-term effects of anemones consumption of plastics and novel assessment endpoints pertaining to crown size.
- The last platform presentation was given by Todd Gouin, TG Environmental Research. He presented “Toward the Development and Application of an Environmental Risk Assessment Framework for Microplastic,” summarizing the findings from International Council of Chemical Associations symposium.
In addition, a set of posters covered new methods and regulatory procedures regarding polymers, see abstract book for details.
At the upcoming SETAC Europe conference in Dublin, there will be a follow-up and in-depth platform and poster session specifically on the environmental risk assessment of polymers. We are also planning an additional open workshop on polymer toxicity analysis during the meeting in Dublin. The polymer related activities are organized by the Improved aquatic Testing and Assessment of Cationic Polymers (iTAP) project (https://projects.au.dk/itap/) supported by Cefic LRI ECO46.
Polymer Analytical Workshop
For the workshop, representatives from industry, government, academia and contract research organizations (CROs) collectively shared their knowledge and insights on the state of the science of new innovative approaches and limitations with a variety of well-established analytical approaches for water-soluble polymers and other difficult chemistries in environmental safety studies.
The purpose of this workshop was to:
- Provide a “prospective review” of published and unpublished analytical approaches for polymers and other similar and difficult to analyze materials in the context of environmental safety testing
- Identify general challenges with water-soluble polymers – limitations of current methods
- Discuss the feasibility of a universal approach and instrumentation that is accessible to scientists at CROs and in academia, industry and government
Workshop discussions focused on guidance and watch-outs, strengths and weaknesses of different analytical approaches that could be used for quantitation, such as wet chemistry, non-specific methods and mass spectral techniques. Scenarios where simpler approaches could be possible and extraction strategies for polymers from matrix were also discussed.
Key findings for wet chemistry and non- or semi-specific approaches are that they have limited scope of utility with respect to testing applications. Potential issues would include limits of detection or quantitation, specificity, clear articulation and knowledge of assumptions, and knowledge of the testing matrix. However, there could be scenarios where these methods could be useful; these are envisioned as situations where data is available to support the use of the methods by demonstrating the polymer is stable to degradation and sorption, can be distinguished from background, and has moderate to low ecotoxicity. On the other hand, mass spectrometry offers the potential for delivering high sensitivity, robust approaches for polymer identification, structure characterization and quantitation to meet environmental safety study needs. However, there are significant development efforts and more attention is needed from analytical, mass spectrometry and environmental safety communities in order to address the various technical and accessibility challenges.
A common theme from the sub-group discussions is that a well analytically characterized polymer is a key aspect to guide the selection of an appropriate analytical method and the design of environmental safety studies. An understanding of the monomers, residuals, molecular weight ranges and other physical-chemical properties are important in selecting the analytical method, in addition to the specific need. This topic is the subject of a recently submitted poster abstract for SETAC Europe in Dublin.
Conclusions from the Session and Workshop
The platform and workshop help set the stage for a future state where polymers will be routinely reviewed in international chemical management programs, similar to existing and newly registered substances. Polymers, however, still provide scientists with unique challenges associated with fate and exposure assessment as well as hazard assessment. Regarding fate, polymers will certainly be considered as UVCBs (unknown or variable composition, complex reaction products or of biological materials), which always present difficult characterization and analytical challenges. Care will be needed to consider new ways to anticipate releases of constituents into environmental matrices. On the hazard side of the risk assessment process, the realization that physical effects may be environmentally relevant open up new considerations for characterizing exposure (dose) – response and aspects of exposure relevance so that the true environmental risk of polymeric substances can be revealed. SETAC will be a key venue for these issues to be explored in a tripartite manner.
Carys L. Mitchelmore, UMCES Chesapeake Biological Laboratory, and Iain Davies, Personal Care Products Council (PCPC)
Overview of Session
The goal of the session was to bring scientists from academia, business, government agencies and other stakeholders together to discuss research regarding the environmental risk of UV filters in aquatic ecosystems. As an emerging but rapidly expanding area of research, many more talks were submitted for this session than we were able to accommodate, and so presentations were selected to represent the diversity of topics from environmental monitoring, chemical fate, toxicology and risk assessment.
Concerns over the environmental impacts of UV filters have received considerable attention in recent years, particularly with respect to coral species, and has led to legislation and policy action restricting sunscreens despite very limited or no data on their environmental concentrations or toxicity to reef ecosystems. While the use of UV filters as active ingredients in sun protection products is widely documented, these materials are also used in many other consumer products, such as plastics, paint, apparel, and may even come from natural sources. Therefore, multiple potential point and diffuse environmental sources of UV filters to the aquatic environment exist, such as bathers and swimmers, wastewater treatment plants and in land run-off due to leaching from products. Monitoring studies have shown highly variable spatial and temporal concentrations in environmental matrices, with the majority of seawater concentrations being reported in the parts per trillion or low parts per billion range.
Risk assessments require 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 scientists working in all freshwater, estuarine and marine locations that have investigated the sources, occurrence and concentration in environmental matrices, fate and effects of UV filters in the aquatic environment, together with industry representatives discussing environmental risk and the potential trade-offs with human health concerns. The session aimed to advance our knowledge of the environmental risk that UV filters may pose and to start a scientifically grounded discussion on the implications and research needs of these compounds in the environment.
As mentioned earlier, presentations were balanced to provide new information on the concentration and fate of UV filters in the aquatic environment (presentations 1–3), their toxicity to aquatic species (presentations 4–7) and a risk assessment summary (presentation 8).
Key points from the eight presentations included:
- The first three presenters discussed issues regarding the concentration and fate of UV filters in aquatic systems to understand potential exposure. Steven Landeweer, Florida International University, found low parts per trillion levels of oxybenzone in Biscayne Bay and investigated the use of silicone passive diffusion releasers to prepare exposure solutions from sunscreens. Equilibrium concentrations varied with time and salinity, although only the parent compound was measured.
- Jean-Luc Boudenne, Aix Marseille University-CNRS, reported on the levels of UV filters in Mediterranean beach waters and in chlorinated seawater swimming pools. Results highlighted the variability of concentrations by site, distance from shore, depth, time of day and number of people in the water. In beach samples overall, no or low parts per trillion levels of oxybenzone and avobenzone were found, the highest concentrations (also parts per trillion) seen were for octocrylene. Octocrylene was also the highest measured in the swimming pools in low parts per billion concentrations, which was attributed to its lack of reactivity to chlorine and photostability in laboratory studies compared with the other UV filters.
- The Chesapeake Bay study presented by Ethan Hain, University of Maryland Baltimore County, showed water concentrations in the low parts per trillion concentration for up to nine organic UV filters and found a linear correlation between oxybenzone and octocrylene levels. Oxybenzone appeared higher near known wastewater treatment plant (WWTP) effluents but did not correlate with sucralose levels. Higher concentrations of UV filters in sediment were generally observed at sites with the higher water concentrations and UV filters were present in oyster tissues.
- The next four presentations focused on studies investigating the toxicity of UV filters, mainly oxybenzone to corals, anemones and Daphnia spp. Diana Slijkerman, Wageningen University, in two coral species coupled a six-week long field-relevant oxybenzone exposure with one of the main drivers of coral bleaching, elevated temperature. The study highlighted limited impacts of oxybenzone alone, species-specific impacts, with Acropora spp. being more sensitive. Effects were much more significant for temperature than oxybenzone, which slightly accelerated Acropora spp. mortality in the higher temperature treatment.
- Danielle Stromberg, Cerege, presented for Alice Tagliati, Heriot-Watt University, on the toxicity of mineral (titanium dioxide) sunscreen formulations (at parts per billion and million concentrations) to adult and larval corals and anemones, again combining these exposures with increased temperatures as projected for future climate change scenarios. Impacts on multiple biological endpoints in sunscreen exposed adult coral were observed in the 12-day exposures and temperature elevation did not enhance the negative effects, although heat-stress enhancement was observed in short-term (24hr) anemone experiments. Acropora fertilization success was not impacted by the two sunscreen formulations, although one of them did result in a higher number of abnormalities (<10%).
- Continuing with adult coral exposures, Annaleise Conway, UMCES Chesapeake Biological Laboratory, reported oxybenzone 96-hour lethal concentrations to 50% of the population (LC50s) in the hard coral Galaxea at ~6mg L-1 (nominal concentration), which is the first reported value in an intact hard coral species and much higher than the only reported value in intact coral (i.e., coral larvae) and orders of magnitude above levels commonly found in seawater near coral reef locations.
- Completing the toxicity discussion, Faith Lambert, University of Florida, investigated the chronic toxicity and acute gene expression of three UV filters (parts per billion concentrations; including oxybenzone) to Daphnia. No effects on molting frequency, growth, reproduction or production of males were observed, but at the highest doses (all orders of magnitude above reported surface water concentrations except for oxybenzone, which was within one reported range), all UV filters caused developmental deformities in offspring and 4-methylbenzylidene camphor (4MBC) increased the time to maturity. Gene expressions were not altered.
- To summarize the session, Iain Davies, Personal Care Products Council, gave an overview of the state of the science and challenges regarding the environmental risk assessments of UV filters. He presented a new a tool to ensure that data used in risk assessments is of sufficient quality for inclusion and presented a way forward for determining the risk of chemical contaminants to coral species.
Conclusions from the Session
The detection, toxicity and environmental risk of UV filters in aquatic ecosystems is a rapidly expanding and emerging field of research. Policy decisions have been made on limited (or no) scientific data, and there are numerous gaps in knowledge critical for risk assessments. However, since the session last year and as evidenced by the four-fold increase in abstract submissions this year, research is being conducted to fill these data gaps. This session highlighted the variable (space and time) concentrations of UV filters, that all were measured in the ng L-1 (parts per trillion ranges) and that reductions and transformations occurred by photolytic pathways or reactions with chlorine. Limited acute and toxicological impacts were observed in three intact adult coral species and Daphnia exposed to environmentally relevant (or higher) concentrations of UV filters, although impacts could be seen at the higher doses and both oxybenzone and titanium dioxide, with oxybenzone exacerbating heat induced impacts in corals. The potential impact to corals and other aquatic organisms needs more research given the highly variable responses observed in the toxicity of oxybenzone between studies. The studies reported in this session show limited impacts to corals exposed to oxybenzone at parts per billion and parts per million concentrations, which contrast the previous study presented during policy decisions. Furthermore, correlations among studies would be greatly enhanced if standard acute and chronic toxicity testing procedures were used and analytical verification of exposure concentrations were conducted. Differences in the quality of data and its importance for consideration for inclusion in risk assessments was highlighted, and a data assessment tool for all aquatic species and a risk assessment framework for corals was presented. It is essential that scientists from academia, business, government agencies and other stakeholders continue to work together to increase the wealth of data available regarding the environmental concerns of UV filters. The discussions from this session are planned to be continued in 2020 at SETAC’s Europe and North America meetings.
Henry Kruger, Eurofins US; Gertie Arts, Wageningen Environmental Research – WUR; and David Olszyk, U.S. Environmental Protection Agency
Plants are the basis for all ecological systems and are affected by a broad range of environmental toxics issues. This session, organized by the SETAC Plant Interest Group, welcomed contributions that focused on new developments in plant ecotoxicology and the use of plants in risk assessment of chemicals and other stressors. The current risk assessments for chemicals usually consider risks for primary producers based on standard tests. Higher-tier approaches are only utilized if plants are the most sensitive for a specific chemical or if these organisms are affected indirectly. These higher-tier approaches might cover both experimental and modeling studies. Besides the fact that chemicals can affect plants, plants can also accumulate and biodegrade chemicals and thus contribute to lower exposure concentrations. This ability of plants is potentially useful for phytoremediation and mitigation purposes and thus, contributions to this topic are also welcome. In addition to these topics, and especially of interest in the context of this SETAC meeting in Toronto, we encouraged contributions that considered risk assessment for invasive plant species and endangered species. Presentations covered aquatic plants (algae and macrophytes) and terrestrial plants. We encouraged presentations that: 1) described new or validated testing methods in lower and higher-tier assessments; 2) addressed reproductive endpoints in terrestrial plant studies; 3) presented new studies or in silico modeling efforts on evaluating effects on plant communities at the field and landscape level; 4) described ecological interactions between plants and other species in relation to stressor exposure, e.g., indirect effects with microorganisms; 5) examined the use of higher-tier testing methods in risk assessment, including plant modeling approaches; 6) and evaluated the effects of herbicide drift on non-target plants. Additionally, presentations highlighted local or regional plant ecology issues for Canada.
The key points from the eight platform presentations included:
- Verena Sesin, Trent University, began the session by describing glyphosate effects and accumulation in native and invasive wetland macrophytes. This information will be useful for environmental risk assessments of glyphosate spray applications in wetlands and for effective and sustainable wetland management.
- Sharareh Dehghani, University of Guelph, evaluated potential use of Alyssum for phytoremediation of nickel contaminated soil at the Port Colborne site in Ontario, Canada. The study showed that phytoremediation using Alyssum spp. may not be an effective approach for this site.
- Ryan Bergin, Queens University, evaluated mercury concentrations in edible plant and fungi species of Iqaluit, Nunavut and the surrounding area, and indicated significant differences in mercury concentrations plant and mushroom species.
- Zhu Hao Yu, University of Toronto, described duckweed–microbe interactions in the elimination of benzotriazole, a corrosion inhibitor, from salt-contaminated water. The results suggested that duckweed has potential to remove benzotriazole from water by biotransformation.
- Sarah Graetz, University of Guelph, provided information on the toxicity of novel fire suppression gels to plant germination and emergence. They reported a large variation in toxicity between the fire suppression gels tested, providing information for a better understanding of the potential effects of fire suppression gels on terrestrial ecosystems.
- John Green, John W. Green-ecostats, reviewed analysis of non-target terrestrial plant studies concerning crop-protection chemicals, including recommendations to eliminate errors and improve the quality of results.
- Dwayne Moore, Intrinsik Environmental, Inc., described a large-scale field spray drift study to evaluate downwind effects of herbicides on non-target plants. No significant herbicide effects were observed in navy bean or lettuce at downwind distances of 30 feet or further from the edge of the application area. The results from this field study contrasted with the higher or larger predicted effects based on modeled spray drift curves and greenhouse bioassays.
- Gertie Arts, Wageningen Environmental Research – WUR, presented experimental studies, which provide long-term data sets for testing population models for Lemna and Myriophyllum spicatum. Results showed an increasing variability in response over time but a clear seasonal pattern with slight declines in frond number, respectively shoot length and biomass, during the relatively warm winters. The data will be published to facilitate testing of models of growth for both species.
In addition to the eight platform presentations, there were nine poster presentations dealing with a range of topics including phytoremediation; experimental design, growth responses, measurement endpoints and statistical analysis relevant to non-target terrestrial plant testing guidelines and analysis; evaluation of models used in risk assessments for terrestrial plants, rhizobacteria and the phytotoxicity of biorefinery relevant compounds, herbicide effects on plants, testing of the emergent macrophyte, Glyceria maxima, for a developing OECD test guideline; and a review of recovery of plants and algae from herbicides in aquatic systems.
Conclusions from the Session
Plants are affected by a wide range of environmental contaminants, including herbicides applied for weed management and fire-suppression chemicals, to name a couple. New experimental data, as well as improved testing methodologies and methods of statistical analysis, will provide important tools for determining the risk to terrestrial and aquatic plant systems for these contaminants.