On average, an individual encounters about 80,000 synthetic chemicals every day. So says Robyn Tanguay, a toxicologist at Oregon State University. Many of those chemicals — from fire retardants in fabrics to drying agents in paint — are untested for toxicity to people. Tanguay and her research team are working to change that. Their results are helping those who make the products we use as well as those who use them.
“There are thousands of chemicals in our environment,” says Tanguay, “and many consumers believe that, in order for them to be used in products, that the manufacturers must have demonstrated that they’re not hazardous or harmful. Actually, that is not a requirement. Some of these compounds can be used commercially without ever assessing their toxicity.”
Tanguay’s lab tests the impacts of chemicals on zebrafish. These small fish are popular in home aquariums and even more useful for research. They reproduce in a matter of hours, and as they grow, changes are visible in their transparent embryos.
Common Path to Development
“Zebrafish are vertebrates just like humans are vertebrates,” Tanguay explains. “In early development, as we develop from a single cell into a complex organism, the process by which a human does that is almost exactly the same as in zebrafish. So when we are asking if a compound could be hazardous to human development, we obviously can’t do those studies in humans, but we can do them using zebrafish.” These small fish open a big window into human health.
In fact, zebrafish have a long history as a research model for understanding development. It was Tanguay, a Distinguished Professor in Environmental and Molecular Toxicology at Oregon State, who pioneered the idea of using them for toxicology studies. For example, she has used zebrafish to study dioxin, a component of the notorious Agent Orange, a defoliant used in the Vietnam War. Dioxin has been associated with cancer and other diseases.
Since the 1980s, scientists have been working to understand the impact of these contaminants on human health. Tanguay and her team have sought to understand the mechanisms by which chemistry interacts with biology.
“Our lab is trying to figure out what is it about the structure of the chemical that makes it safe or unsafe,” Tanguay adds. “Just because there are hundreds of thousands of compounds in the environment, doesn’t mean they are all dangerous. In order for a chemical to be dangerous, it has to have the ability to interact with an organism in a way to cause harm.”
While most of us might not think of 80,000 chemicals as a feature of our environment, Tanguay’s definition includes everything from carpets to plastic packaging on food.
“Environment is everything. What’s in the air we breathe, the food we eat, the products we use, the lotions, the sunscreens, the cosmetics,” he says. “All of that is your environment. When you start realizing how complex those environments are, that’s how you come up with very large number of chemicals in those environments.
“The fact is that the chemicals in those environments are dynamic; they’re changing into different chemicals. So now, not only do we assess the original chemical, now each one has given rise to dozens of other compounds.”
Scientists in Tanguay’s lab focus on a range of topics, from environmental contaminants to how zebrafish regenerate fins and other tissues. To make time for all of these projects, Tanguay’s team has created robots and other innovations that allow scientists to run multiple tests at one time. Each test takes five days, and they are testing hundreds of chemicals at any given time.
Sharing the Results
So what happens when the identify a chemical with toxic properties? Tanguay goes into outreach mode. She communicates the results to manufacturers and to government agencies. She also suggests alternative chemicals that do not pose risks to human health.
“If you were a consumer, you may avoid the chemicals that are toxic; that would be good information to have,” she says. “If you were a manufacturer concerned about safety, if you could find a safer alternative for the development of your product, they need to know that as well.”
Tanguay gives presentations at conferences and consults for companies that need his expertise. As for classifying chemicals, she says this is just the beginning in what she hopes will be a transformation of the field of toxicology. Both consumers and manufacturers, she says, need this information.
Listen to Robyn Tanguay describe her research in this Terra Talk podcast.