Common Plastic Ingredient May Cause DNA Damage, Harvard Study Finds

A chemical in common-use plastics may cause DNA damage and infertility in women, according to a new Harvard Medical School study.

The study — led by HMS professor Monica P. Colaiácovo — exposed roundworms to benzyl butyl phthalates — BBPs — which are chemicals added to plastic products to increase their flexibility. BBPs are found in many common consumer products including food packaging, cosmetics and children’s toys.

Results showed that exposure to BBPs led to an increase in germ cell death, DNA damage, and chromosome nondisjunction in C. elegans, a worm commonly used in experiments. The Public Library of Science Genetics published the study in late October.

Colaiácovo explained in an interview with The Crimson that the plastics led to problems with cell division in egg and sperm cells — which can cause abnormal chromosome numbers in developing embryos.

“We know that problems during meiosis can then be linked to things like infertility, miscarriages, birth defects,” she said.

Ami R. Zota, an associate professor at the Columbia University Mailman School of Public Health who has researched plastics in food, said that the risks of these plastics have been known for decades.

“We know that phthalates are endocrine disruptors, which means they interfere with hormone regulation,” she added.

Kurunthachalam Kannan, a researcher from the University of Albany who contributed to the study, said that these findings reveal how dangerous daily exposures to BBPs are.

“In lab studies, people dose animals with very high concentrations, and those concentrations are maybe 10 times higher than what we normally get exposed to,” said Kannan. “But this study has used environmentally relevant exposures, which means that we know we are exposed to these kinds of concentrations on a daily basis.”

Colaiácovo said that the original interest in the impacts of phthalates on reproductive health stemmed from the high numbers of chemicals in the urine of pregnant women.

To conduct the study, researchers exposed C. elegans to varying concentrations of BBP.

“At that dose of exposure, you're affecting the germline, which ultimately affects the quality of those oocytes,” Colaiácovo said. “So a lot of the embryos are not fully developing.”

Despite the importance of the study, Zota said that the general public does not know enough about the harmful impacts of phthalates and that the government needs to help spread the word.

“Scientists alone cannot educate the masses on this issue,” Zota said.

For future studies, Colaiácovo said she is interested in exploring the impacts of BBP on the male reproductive system, as well as differences in impacts for those exposed at different ages.

“We really need to start understanding why there's so much variability on the effects,” Colaiácovo said.