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Phthalate Exposure Trends from 2001 to 2010

Ami Zota, Sc.D.
University of California, San Francisco
NIEHS Grant K99ES019881

An NIEHS grantee and colleagues report that Americans are being exposed to significantly lower levels of some phthalates while exposures to other phthalates are rising. Phthalates are used to make plastic more flexible and are found in hundreds of consumer products. A federal law that took effect in 2009 banned some phthalates from use in children's articles such as toys, permanently banned other phthalates, and put three phthalates under an interim ban, pending further study, from use in toys that can be placed in a child's mouth.

To examine how phthalate exposure is changing over time, the researchers combined data on 11 phthalate metabolites from 11,071 participants in five cycles of the Center for Disease Control’s National Health and Nutrition Examination Survey (NHANES). From 2001 to 2010, the researchers found decreases in exposures to permanently banned phthalates—butylbenzyl phthalate (BBzP), di-n-butyl phthalate (DnBP), and di(2-ethylhexyl) phthalate (DEHP). Children showed consistently higher DEHP exposures than adults, but the difference between the age groups lessened over time. Exposures increased for the phthalates that Congress banned pending further study—di-n-octyl phthalate (DnOP), diisodecyl phthalate (DiDP), and diisononyl phthalate (DiNP). DnOP exposure increased by 15 percent and DiDP by 25 percent while DiNP went up nearly 150 percent, most likely because industry is using DiNP to replace other phthalates such as DEHP. Exposure tripled for diisobutyl phthalate (DiBP), which hasn’t been subject to federal restrictions. DiBP may be replacing diethyl phthalate (DEP), which was a focus of early activism regarding chemicals in cosmetics. Exposure to DEP decreased 42 percent.

The researchers say that the trends they observed are difficult to explain but may at least partly reflect the effects of legislative activity and advocacy efforts of nongovernmental organizations on consumer behavior and the use of phthalates in consumer products.

Citation: Zota AR, Calafat AM, Woodruff TJ. 2014. Temporal trends in phthalate exposures: findings from the national health and nutrition examination survey, 2001-2010. Environ Health Perspect 122(3):235-241.


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