Nearly one in four American women of childbearing age have high blood levels of three dangerous environmental chemical pollutants — lead, mercury, and PCBs — that could pose significant health risks, new research shows.
The study, by Brown University researchers, found 23 percent of American women aged 16 to 49 years met or exceeded the median blood levels for all three contaminants. More than 80 percent of the women aged were at or above the median blood level for one or more of these chemicals, which can be passed to developing fetuses through the placenta and to babies through breast milk.
The study, published in the journal Environmental Research, suggests the chemicals remain pervasive in the environment and can harm fetal and infant brain development, said lead researcher Dr. Marcella Thompson.
"Our research documents the prevalence of women who are exposed to all three of these chemicals," said Thompson, a postdoctoral research associate for Brown University's Superfund Research Program. "It points out clearly the need to look at health outcomes for multiple environmental chemical co-exposures."
For the study, Thompson and colleagues analyzed data were collected between 1999 and 2004 from 3,173 women who participated in the Centers for Disease Control and Prevention National Health and Nutrition Examination Survey.
The results showed older women were more likely to have higher levels of the pollutants in their blood; those 30 to 39 had a 12 times greater risk and women aged 40 to 49 had a risk 30 times greater than those women aged 16 to 19. Thompson said older women are at greatest risk because chemicals accumulate in the body over time and those born in the 1950s and 1960s were alive before most environmental protection laws were enacted.
Women who ate fish more than once a week or were heavy drinkers also had higher blood levels of the contaminants. Some varieties of fish, like swordfish and albacore tuna, can contain high levels of mercury and PCBs, Thompson said. But she said there is no explanation for the link between heavy drinking and a higher level of pollutants.
Although the study did not measure whether women with higher levels or their children suffered ill health effects, Thompson said the findings suggest that women need to learn about their risks from chemical exposures.
"We carry a history of our environmental exposures throughout our lives," Thompson said.
The study was funded, in part, by the National Institute of Environmental Health.