by University of California, San Francisco
When her kids were young, Tracey Woodruff, Ph.D., MPH, knew more than most people about environmental toxics. After all, she was a senior scientist at the Environmental Protection Agency (EPA). But even she never dreamed, as she rocked her children to sleep at night, that the plastic baby bottles she used to feed them contained toxic chemicals that could leach into the warm milk.
Back then, in the late 1990s, it wasn’t widely known that the chemicals used in plastic sippy cups and baby bottles can potentially disrupt child development by interfering with the hormone system. That, in turn, could alter the functionality of their reproductive systems or increase their risk of disease later in their lives.
“When I had babies, I did many of the things we now tell people not to do,” says Woodruff, who for the past decade has been the director of UC San Francisco’s Program on Reproductive Health and the Environment (PRHE). Also a professor in the University’s Philip R. Lee Institute for Health Policy Studies, she earned her doctorate in 1991 from a joint UCSF-Berkeley program in bioengineering and then completed a postgraduate fellowship at UCSF.
Woodruff’s children have since grown into physically healthy teenagers, but many children are not as lucky. Unregulated chemicals are increasing in use and are prevalent in products Americans use every day. Woodruff is concerned by the concurrent rise in many health conditions, like certain cancers or childhood diseases, and the fact that the environment is likely to play a role in those conditions. What motivates her is the belief that we need to know more about these toxics so we can reduce our exposure to the worst of them and protect ourselves and our children from their harmful effects. (Woodruff points out that the word “toxics” as a noun means any poisonous substances, from either chemical or biological sources, whereas “toxins” are poisons only from biological sources, either plant or animal.)
The PRHE is dedicated to identifying, measuring and preventing exposure to environmental contaminants that affect human reproduction and development. Its work weaves together science, medicine, policy and advocacy.
For example, research over the past 10 years by UCSF scientists and others has showed that bisphenol A (BPA) – an industrial chemical used since the 1950s to harden plastics in baby bottles, toys and other products – is found in the blood of those exposed to items made with BPA and that it can harm the endocrine systems of fetuses and infants. As a result, the Food and Drug Administration (FDA) outlawed BPA in baby products in 2012, and some manufacturers developed BPA-free products. But now scientists believe the chemicals that replaced BPA may be just as harmful.
Furthermore, BPA is only one in a long, long list of chemicals we encounter every day in our homes, schools, workplaces and communities. And scientists have barely scratched the surface of understanding them. Of the thousands and thousands of chemicals registered with the EPA for use by industry, the agency has regulated only a few.
“In the last 50 years, we have seen a dramatic increase in chemical production in the United States,” Woodruff explains. Concurrently, there’s been an increase in the incidence of conditions like attention deficit hyperactivity disorder (ADHD), autism, childhood cancers, diabetes and obesity. “It’s not just genetic drift,” Woodruff maintains.
And we’re all at risk from increasing chemical exposure. The water we run from our taps, the lotion we smear on our skin, the shampoo we rub in our hair, even the dust in our houses is full of synthetic chemicals.
Preventing exposure in babies
PRHE experts do more than just measure such trends. They also collaborate with clinical scientists and obstetricians at Zuckerberg San Francisco General Hospital (ZSFG), so their findings directly benefit pregnant patients. “We partner with the clinical scientists,” explains Woodruff, “because they look at treatments for disease, and environment might be a missing factor in the cause and prevention of disease.”
Though environmental toxics affect us all, there’s a reason PRHE focuses on pregnant women and children, Woodruff adds. Exposure to even tiny amounts of toxic substances during critical developmental stages can have outsize effects. So exposure to toxics is especially detrimental to fetuses, infants and young children, as well as preteens and teenagers.
“If you prevent the problem at the beginning, you get a lifetime of benefits,” says Woodruff.
The U.S. Centers for Disease Control and Prevention (CDC) began measuring human exposure to chemicals in 1976. These so-called “biomonitoring” studies found a range of toxics in subjects’ blood and urine – substances like DDT, BPA, air pollutants, pesticides, dioxins and phthalates. Phthalates, for example, are a class of chemicals known to be endocrine disruptors but widely used as softeners in plastics and as lubricants in personal-care products. Biomonitoring has determined that women of reproductive age evidence higher levels of phthalates than the population at large. One reason, says Woodruff, is that young women use more products like perfume, deodorant, shampoo and conditioner.
Woodruff herself recently led a study in which UCSF researchers collected blood samples from pregnant women at ZSFG. After the women delivered their babies, the researchers collected umbilical cord blood samples – and discovered that almost 80 percent of the chemicals detected in the maternal blood samples had passed through the placenta to the cord blood. It was the most extensive look yet at how the chemicals that pregnant women are exposed to also appear in their babies’ cord blood (and followed an earlier study by Woodruff that marked the first time anyone had counted the number of chemicals in the blood of pregnant women). Published in the Nov. 1, 2016, print edition of Environmental Science and Technology, the study also found that many chemicals were absorbed at greater levels by the fetuses than by the pregnant women…