Home may be where the heart is, but environmental chemist Miriam Diamond has a more troubling perspective on the home: as a place where harmful substances migrate out of couches and electronic devices to accumulate in dust, adhere to our hands, and eventually make their way into our bodies. She and her team at the University of Toronto chemically pick apart our homes and how we interact with the stuff in them so that researchers can come up with solutions to protect us from toxic compounds, such as flame retardants. Diamond talked to Janet Pelley about how she tracks contaminants in the home and why you might want to regularly clean your cell phone.
▸ Education: BSc, biology, University of Toronto, 1976; MSc, zoology, University of Alberta, 1980; MScEng, mining engineering, Queen’s University, 1984; PhD, chemical engineering and applied chemistry, University of Toronto, 1990
▸ Favorite nonscientist investigator: Diana Rigg in the 1960s spy series The Avengers. “Diana Rigg was one of the first TV heroines who wasn’t passive. And she wore a pantsuit.”
▸ What motivates you: “I feel more impassioned and compelled than ever to work for positive change. I need to make sure that my kids and hopefully grandchildren have a good world to live in.”
▸ The last book you read: iGen by Jean M. Twenge. “Her analysis linking children’s growing mental health issues to dependence on cell phones and the internet gives me even more motivation to look at contaminant levels, especially fetal exposure to endocrine disruptors.”
How did you gain your special perspective on the home?
My master’s degree in bird behavior trained me to sit and watch birds, which has been very valuable, not only when watching people and their behaviors but also in noticing what’s going on in the environment. It forces you to see the world through other people’s eyes.
Scientists have long analyzed the transport of toxic chemicals outdoors. How did you bring those kinds of studies indoors?
When I began my PhD, I studied lakes, and my adviser taught me that you can draw a box around the lake and model the movement of chemical compounds into and out of the lake. So we applied that concept to the indoor environment and said, “All right, the carpet is now the sediment where chemicals from consumer products settle, and we have the indoor air where they get resuspended.”
When my students and I first began to model the indoor environment, we didn’t include humans as agents moving chemicals around the way fish move compounds around in a lake. But one day, I watched my son bouncing on the couch, and I thought, “Wow, look at that opportunity for chemical transport.” What the bouncing is doing is accelerating the exchange of fire retardants between the polyurethane cushion and the air way faster than if the cushion were just sitting there.
How did that lead you to cell phones?
We knew that we wanted to measure organophosphate ester (OPE) flame retardants and plasticizers on the surfaces of stereos and TVs, as well as laptops and tablets. Any electronic device that heats up will promote the release of flame retardants and plasticizers added to the plastic components. Emerging studies link some of the OPEs with fertility problems in women, developmental effects in kids, and higher likelihood of some cancers in adults. Manufacturers are using more and more OPEs as both flame retardants and plasticizers.
At the last minute, I got one of those intuitions to take wipe samples from the cell phones as well as from the other devices. So we went to the homes of 51 women in Ontario and measured levels of OPEs in the air and dust and on their hands and analyzed concentrations of the metabolic products of OPEs in their urine, as well as the levels on the surfaces of the electronics we were targeting.
We found that the level of OPEs on their cell phones was associated with what was on their hands and that the levels were significantly associated with urinary metabolite levels (Environ. Int. 2019, DOI: 10.1016/j.envint.2018.10.021). When you say it after the fact, it seems so obvious because your hands are in constant contact with a cell phone. And work by Heather Stapleton at Duke University has shown that your hands are an indicator of your exposure to flame retardants. Our study was consistent with the idea that the hands are delivering the OPEs to your body through hand-to-mouth transfer or absorption through the skin.
Could cell phones be the source of OPEs, or are they just an indicator of total exposure to OPEs in the home?
We found so many different OPEs on the cell phones that I thought, No, cell phones can’t have that many flame retardants, and they certainly don’t have all those plasticizers. I bet that it is picking up the chemicals from all the sources we come in contact with over the day. Your hand moves from product to product. Because people don’t wash their cell phones, the devices accumulate the chemicals. Then people tap, type, swipe, and click their cell phones thousands of times per day, which provides the opportunity for transfer and exposure.
What is your next project?
We’re working on modeling how hands move chemicals around.
I’ve been inspired by new forensic research where scientists identified the chemical traces that fingerprints leave on cell phones, which could tell what medications you are on or if you ate oranges that morning. I put that together with literature on how diseases are spread by hands—like a horrifying study on how the norovirus was spread on an airplane flight. The message of these studies is that hands are spreading compounds and disease agents around the indoor environment and one of the repositories is your cell phone.
Your hands move things around much faster than conventional transport mechanisms such as diffusion through the air. It’s the concept of the kid bouncing on the couch—the toddler resuspending the dust while crawling all over the place and moving chemicals around. Humans are the agents moving chemicals around the house and, in so doing, exposing themselves to the compounds.
What is the best way to protect ourselves from contaminants in the home?
Regularly wiping down the cell phone should help. But more important is to live a simpler life filled with less stuff and gizmos. The idea is similar to how you eat lower on the food chain to live a more sustainable life. If you consume fewer electronic goods, you can reduce your exposure to risky chemicals.
What impact would you like your work to have?
It has always been my goal to connect the dots between releases of industrial chemicals to environmental exposure and health. I take my responsibility as a public servant very seriously, so my goal has always been to do policy-relevant research and then convey that information. I enjoy engaging with the press to help the science that we do live a life outside of academia.
Janet Pelley is a freelance writer. A version of this story first appeared in ACS Central Science: cenm.ag/diamond. This interview was edited for length and clarity.