Context and Perspective in Ecotoxicology

If you were to gather a group of ecotoxicologists in a room and ask each what the most significant chemical threat is to the environment, chances are you would find as many different contaminants as individuals. Perhaps a more difficult question would be which, if any, truly represents an existential environmental threat relative to macro-scale problems, such as habitat loss, invasive species, disease and pathogens, or climate change. Even when contaminant impacts are clear and pronounced, effects tend to be localized and, in many cases, without broader, lasting ecological implications (e.g., effects of estrogenic compounds in wastewater on fish, soil, and plant biodiversity at contaminated industrial sites or impairment of fish and benthos due to mine or pulp and paper mill effluent). In our minds, this raises the issue that perhaps, as a discipline, we have lost context and perspective on the role of ecotoxicological research, potentially to our peril. Anecdotally, but with seemingly regular occurrence, we observe that when research is featured in the popular press or even at conferences, the narrative often conveys proclamations of profound outcomes associated with the newest "bad actor." Yet many studies pronouncing the next watershed moment in the field of ecotoxicology often suffer from lack of replication, inconsistency of observed effects, and methodological flaws and are frequently taken out of context (see the discredited case of microplastic toxicity in fish for an example of confirmation bias overwhelming common sense [Lönnstedt and Eklöv 2016]). Overall, it is rare to see a narrative indicating "this issue is really not a significant problem," and although some media outlets have a propensity to stoke sensationalist fires, we as ecotoxicologists should not. As scientists, we need to ensure that the relative risks associated with anthropogenic stressors are put in their appropriate context. Unless we cast a critical and introspective eye, we risk overemphasizing contaminants as seminal anthropogenic drivers of environmental change that may actually be ancillary (relatively speaking), potentially resulting in a gradual deterioration in credibility regarding our role in a much broader collective effort to preserve and enhance environmental protection; and we are not alone in sharing this concern (see Burton 2017a, 2017b; Johnson et al. 2020). This is effectively a call to intellectual self-awareness such that when we identify something as a consequential "problem," it is one, one that justifies corresponding resources to resolve. The question of why ecotoxicologists tend to "up-sell" is a complicated one, worthy of further discussion because it speaks to a root problem but may be explained by the same motivators that influence science research in general at times (e.g., the need for funding, the need to publish, the need for impact, the desire for career advancement [Hanson et al. 2018]). This discussion is in no way meant to diminish what we do and have done as scientists and our significant contributions to environmental protection. Nor is it to say that contaminants have not, could not, and do not have potential to cause ecological harm. We are also not advocating that contaminants be introduced to our soil, air, or water unimpeded or unregulated; in fact, the opposite is true. Robust regulatory oversight grounded fundamentally in science is critical and, in many cases, highly effective at ensuring that contaminants do not result in unacceptable impacts (though the definition of what is or is not acceptable is not always explicit). What we are saying is that we need to be conscientious, pragmatic, and judicious with respect to defining and declaring consequential agents of environmental change. Stepping back, it is important to remember that ecotoxicology emerged as a response to a growing awareness of actual observed impacts of inadequately regulated chemicals used in industry and agriculture on the environment (Hoffman et al. 2002). Consequently, laws and regulations were created, primarily in the United States initially, to oversee the evaluation and approval of new and existing chemicals (e.g., the Federal Environmental Pesticide Control Act of 1972, the Toxic Substances Control Act of 1976, and the Comprehensive Environmental Response, Compensation, and Liability Act of 1980) and ensure the protection of sensitive species (e.g., the Endangered Species Act of 1973). Domestically, these have since expanded dramatically, and variations have been adopted internationally, including global treaties (Stockholm Convention on Persistent Organic Pollutants of 2001). In turn, the Society of Environmental Toxicology and Chemistry (SETAC) was born as a forum to bring tripartite stakeholders (industry, government, and academia) together and has advanced science in the service of environmental protection for over 40 yr. We have now undoubtedly reached a point where, for the majority of ecotoxicologists and SETAC members, these milestones and the events that precipitated them predate living memory. Our history is becoming just that—"history." We feel it is time to critically reflect and reevaluate how we as scientists think about, prioritize, and tackle potential contaminant threats to ecosystems and society as a whole. All of us can think of examples where a chemical contaminant was highly problematic and, as a result of regulatory oversight, effective action was taken; and many of these compounds are now "legacy" issues (e.g., organochlorines and polychlorinated biphenyls). More recently, the most significant contemporary species loss explicitly known to be contaminant-related was a result of vultures inadvertently exposed to the pharmaceutical diclofenac (see Oaks et al. 2004). This is an elegant case study in how conservation biology and ecotoxicology worked together to successfully identify and address an observed decline in a species. A number of putative causes were hypothesized (pesticides, metals, disease) and tested, allowing for a weight-of-evidence determination of cause, and ultimately for action to be taken, hopefully in time to save this species from the brink of extinction. However, if our impulse is to simply implicate the contaminant sujet du jour et intérêt, we collectively run the risk of potentially identifying and addressing the wrong source of the right problem. This will ultimately erode our credibility in the court of public and professional opinion and do the environment no good. To help obtain perspective and ensure that ecotoxicology remains a significant contributor to environmental protection, we suggest the following. 1) Know the regulatory framework that oversees stressors of interest. Will your studies contribute to data gaps and ensure that effects are effectively and pragmatically mitigated? How are you helping to improve that regulatory framework? To echo Johnson et al. (2020), are more studies on the effects of ethinyl estradiol in fish really needed by regulators? 2) Familiarize yourself with what is being done in other disciplines in the areas of environmental protection (e.g., conservation biology, agriculture, forestry, engineering) and what they see as the major drivers of ecological change. To illustrate, today bird populations in North America and elsewhere are influenced by several significant drivers, such as invasive species (including domestic and feral cats), collisions with buildings, habitat loss, and poaching, that ultimately eclipse contaminant contributions (Brain and Anderson 2019), many times without the benefit of concerted regulatory oversight to help address. 3) Perform simple thought experiments. a) If this contaminant were to disappear, what specific and measurable improvements would occur and over what time frame? b) What could be the negative or unintended consequences of its prohibition (e.g., are the replacements or alternatives worse)? 4) Characterize the scale of a given contaminant's influence. What are the extent and magnitude of exposure? Is this a local, regional, or global issue? 5) Consider the totality of causal evidence in support of the hypothesis that the contaminant contributes significantly to environmental harm. Is it truly compelling? 6) Each of us should be our own toughest critic. What data or studies would refute your hypothesis of harm? Are you performing those studies yourself? 7) Finally, and perhaps most importantly, be open to the notion that your contaminant of interest/research may not be the fundamental issue. Again, we do not want to make it appear as though a problem has been solved when the underlying fundamental issues remain. This should not be seen as a failure but rather a good news story—"This is not a significant problem." Ecotoxicology has made and continues to make valuable contributions to collectively protect the environment. We think we can best live up to our potential, and those of future ecotoxicologists, by remembering to step back occasionally to see the entire (figurative) forest and not just the trees. We want to thank T. Black for providing feedback on an earlier version of this document. M.L. Hanson was not compensated for his work on this Points of Reference. He has had research funded by Syngenta Crop Protection in the past. Data, associated metadata, and calculation tools are available from the corresponding author (mark.hanson@umanitoba.ca).

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