SPHHS Professor Ami Zota reports on a decade of Americans’ exposure to phthalates.
Despite drops in levels of some types of phthalates— found in children’s toys, nail polish and other beauty products—Americans are still being exposed to the potentially damaging chemicals, according to research from Ami Zota, an assistant professor of environmental and occupational health at the George Washington University School of Public Health and Health Services.
Phthalates, which are used to soften plastic, have been linked to health problems, including DNA damage in sperm as well as cognitive and behavioral problems in children. Some scientific evidence suggests they can disrupt the endocrine system, and there is concern that widespread exposure to such chemicals might trigger future health problems.
Dr. Zota’s study, published in Environmental Health Perspectives this month, reports on trends from 2001 to 2010. The researchers investigated the exposure of eight different phthalates among 11,000 people who took part in the National Health and Nutrition Examination Survey conducted by the U.S. Centers for Disease Control and Prevention. Dr. Zota conducted her research while a postdoctoral fellow at the University of California San Francisco.
This study, like previous reports, found that nearly all the participants had been exposed to at least some of the phthalates that were measured, including those that have been partially banned by the federal government.
Exposure to the phthalates subject to a permanent federal ban in children’s toys that took effect in 2009—BBzP, DnBP and DEHP—decreased between 2001 and 2010. While paradoxically, exposures to the phthalates that Congress banned pending further study—DnOP, DiDP and DiNP—increased.
DiNP levels increased by nearly 150 percent between 2005 and 2010. Industry has used DiNP to replace other phthalates such as DEHP. In December, DiNP was added to the list of chemicals known by the state of California to cause cancer under California’s Proposition 65.
“We were excited to see that exposure to some of the phthalates that are of public health concern actually went down,” Dr. Zota said. “Unfortunately, our data also suggest that these are being replaced by other phthalates with potential adverse health effects.”
These findings raise public health concerns, because phthalates still being produced can be found in nail polish, fragrances, plastics and building materials, food packaging and in the food supply. They can be inhaled, ingested or absorbed through the skin.
The federal ban is not the only force at work in determining phthalate exposures. Both consumers and industry have changed their behavior in response to advocacy by groups like the Campaign for Safe Cosmetics. Since 2004, more than 1,000 companies have agreed to remove certain chemicals from personal care products and report more clearly what chemicals they are using.
Possibly as a consequence of these changes, the study found dramatic changes in exposures to DEP and DiBP, neither of which has been subject to federal restrictions. Exposure to DEP fell 42 percent since 2001, while DiBP tripled.
DEP was widely used in the consumer care products that were the main focus of the early activism. Dr. Zota and her team believe industry may be using DiBP as a replacement, both in personal care products and in solvents, adhesives and medication.
But researchers said it is hard to know how changes in industry preference and consumer behavior are affecting human exposures, given how little is known about the chemical composition of consumer products.
“This study shows the importance of monitoring chemical exposures in the U.S. population so we can identify where we have made progress and what we need to tackle next,” Dr. Zota said.