Modern-Day Challenges for Environmental Toxicology Labs
How environmental toxicologists navigate emerging toxicology issues
Cutting-edge technology like high-throughput screening and omics offer contemporary ways to study ecotoxicology. However, determining their relevance to real-world scenarios can be tricky. It often takes a multidisciplinary approach, innovation, and teamwork to successfully mitigate and minimize the effects of environmental contaminants on ecosystems and human health. Here, we discuss the significance of tackling the challenges involved in managing an ecotoxicological lab with Joel Meyer, professor of environmental molecular toxicology in the Division of Environmental Sciences and Policy at the Nicholas School of the Environment, Duke University. Note: These responses have been edited for clarity and style.
Q: What are some of the unique challenges that environmental toxicology labs are facing?
A: [For our lab,] one challenge is deciding which toxicants to study. As humans, we produce and use hundreds of thousands of chemicals. Yet, we do not fully understand which are most important in terms of exposure and toxicity.
Another challenge is deciding which biological effects to study because pollutants can cause toxicity in several ways. These mechanisms of toxicity range from short-term toxic effects such as air pollution triggering inflammatory responses in the lungs to the interactive effects of metal exposures and poor nutrition health.
A final unique challenge is that we often lack critical information about the chemicals themselves, or about the biology that they affect—all of which are being studied by members of the lab.
Because some of our research supports the US Congress-funded Superfund Research Program that targets polluted sites in the US, we base our decisions on the US government's Substance Priority List which is compiled by experts at the Environmental Protection Agency and the Agency for Toxic Substances and Disease Registry. We also try to be on the lookout for new and emerging pollutants, or those of great importance in places other than Superfund sites.
Q: What areas of toxicology research are trending now?
A: There are many! A postdoctoral researcher in my laboratory, Javier Huayta, is working on understanding the effects of mixtures of chemicals on developmental neurotoxicity. This is an important area, as we are all exposed to mixtures of chemicals in the environment, but most environmental toxicology research has historically involved studying the effects of one chemical at a time. Huayta is also studying how pollutants that affect mitochondrial function change health spans as it is critical to understand the subtle but important effects of chronic, low-level exposures. Additionally, several other PhD candidates are studying human health as a function of the interaction of genetic differences, environmental toxicity stressors, and lifestyle factors such as diet, the microbiome, exercise, and more.
Q: What types of instruments and methodologies most applicable for this research?
A: My laboratory uses a combination. We rely heavily on various microscopy techniques, functional analyses of mitochondria (including oxygen consumption and production of reactive oxygen species), gene expression analysis using molecular and 'omics tools, transgenic and mutant strains of the nematode Caenorhabditis elegans (C. elegans), biochemical analyses such as enzymatic activities, and sequencing to identify DNA mutations, such as Duplex Sequencing.
A rapidly growing methodology is the development of pluripotent stem cells, organoids, and alternative model organisms such as C. elegans, to reduce the historic reliance on mammalian models such as rats and mice for toxicology research. This is motivated by the desire to test chemicals economically, given that there is so much that we understand poorly. We are actively working with colleagues and collaborators to develop better instruments and tools for handling, measuring, and imaging C. elegans.
From my perspective, it is critical in environmental toxicology to bring to bear the complementary strengths and limitations of different instruments, methods, and model systems. No one approach is sufficient to safeguard human and environmental health.
Q: Can you elaborate on the importance of interdisciplinary collaboration in addressing complex environmental toxicology issues?
A: Interdisciplinary collaboration is crucial. To understand how environmental stressors affect health, we need to understand the exposure pathway of chemicals, their movement through the environment, and what concentrations are found in people or other species—which are done by environmental chemists. We also need to understand how chemicals are altered in our bodies, how they are eliminated, and their biological effects. Through the understanding of biological effects, the work of toxicologists, then, not only includes interactions at the molecular and biochemical levels but also higher levels.
There is also an increasing use of bioinformatics and data science approaches in environmental toxicology. Environmental toxicologists collaborate with epidemiologists to compare results from controlled laboratory conditions to those observed in humans. We work with community groups and cater to the online dissemination of environmental health information. This helps us understand community needs and promote the public understanding of science. We also work with environmental engineers to try to develop better technologies to remove pollutants and remediate polluted sites.
Q: How do you see the future of per- and polyfluorinated substances (PFAS) regulation and research?
A: There are thousands of PFAS and it is far too many to individually test them all thoroughly for potential toxic effects. In some ways, this is true of chemical exposures in general. However, an advantage of PFAS is that there are structural characteristics (chain length, whether the molecule is fully fluorinated, what functional groups are present, etc.) that define the physical-chemical space of this class of chemicals. Important ongoing efforts to use these characteristics to develop structure-activity relationships that allow some degree of prediction of environmental behavior and toxicity may permit the development of regulations based in part on inference. While not ideal in terms of protecting health, if supplemented by some high-throughput toxicity testing, this would be a significant improvement over the current situation.
Q: In your opinion, what do you see as the “next big thing” for environmental toxicology?
A: There are many possible answers to this, as new exposures or diseases will likely surprise us. But something that we already know about (but still have a lot of work to do) is to understand holistically integrating exposure to multiple chemicals with other stressors (poor diet, lack of exercise, psychosocial stress, infectious diseases) and genetic differences. Some of us are at more risk than others to the same exposures due to such differences. Likewise, we may be able to increase our resilience to, and recovery from, exposures by changes to diet, activity level, and other lifestyle choices.
Professor Joel Meyer's passion for environmental toxicology and its impact on human health was sparked by his experiences building cookstoves, latrines, and observing water pollution. As the lab manager of the Meyer Lab at Duke University, he leads a team of researchers dedicated to studying the effects of toxic substances on the environment and human health. Meyer is a faculty member of the Integrated Toxicology and Environmental Health Program, a member of the Duke Cancer Institute, an affiliate of the Duke Global Health Institute, and a faculty member of the Pharmacological Sciences program.