Taking the long view on toxic chemicals

Robert Scherzer

WHO

Emily Monosson

WHAT

Monosson, an independent toxicologist and adjunct faculty member at the University of Massachusetts Amherst, says we need to take a longer-term view of the potentially dangerous chemicals in our environment. She gave a talk last week at the Harvard Museum of Natural History about her new book, “Evolution in a Toxic World: How Life Responds to Chemical Threats.”

Q. What do you mean when you say we need to take an “evolutionary perspective” on toxic chemicals?

A. I think adding an evolutionary perspective to the science of toxicology might help us better understand how chemicals interact with living things. Toxicology has done pretty well at protecting the public, but we know that it needs to improve. [There are] a lot of problems today that we’re not quite addressing.

Q. Why is it so hard to figure out which chemicals we need to worry about?

A. There are tens of thousands of chemicals we’ve put into the environment over the last 100 or so years. Toxicology as a science came into being around the same time and evolved itself as a regulatory, management, top-down approach to figure out which chemicals were harmful and which weren’t. [At a time] when exposures were high, and there were fewer chemicals, it did pretty well with identifying and regulating the most obvious problems.

Q. But that’s not enough anymore?

A. There’s a lot that’s slipped through. By thinking about how living systems evolved to cope with toxic chemicals — if you could understand that, maybe you’d understand how new chemicals might interact with the systems.

Q. And we need to start looking at how chemicals interact with each other?

A. We’ve been looking at a single chemical, single response, or a single organ. We know that’s oversimplified.

Q. Can you describe a biological system that evolved to protect us from toxins?

A. Earth is a pretty toxic place and always has been. It was probably more toxic when early life was first evolving. The sun — UV light and radiation — it’s a potent carcinogen, it can disrupt DNA. One of the oldest defense mechanisms that evolved in single cells billions of years ago is an enzyme that repairs a particular type of DNA damage.

Q. Your most recent work has involved systems that rapidly evolve in response to toxins. What is the significance of this?

A. There are a few examples of where [even] vertebrates have evolved within a dozen generations in response to toxic chemicals. Trying to understand the underlying responses that lead to that might help us better predict how and when it might happen, and how quickly species can adapt.

Q. How is this idea important to us today?

A. Things like antibiotic and pesticide resistance are big problems. Another one is herbicide resistance.

Q. Do we have the political will and scientific wherewithal to change the way we develop chemicals?

A. A lot of people realize we need to do things differently. If from the very beginning students were taught to take an evolutionary perspective, it might help them to think about things a little bit differently. Maybe, if we can do that going forward, we’ll build a stronger base to the science.

Q. What drives you in this work, where does your passion come from?

A. I just think it’s a really fascinating way to look at things. Maybe that’s just the geek in me, but if you look at your hand or breathe in and think about those enzymes at work [protecting against damage from the sun, oxygen, and other toxins] — they have been working for billions of years. That’s pretty cool.

KAREN WEINTRAUB