(NaturalNews) The majority of women of childbearing age have higher-than-average blood levels of at least one pollutant that can damage infant brain development, according to a study conducted by researchers from Brown University and published in the journal Environmental Research.
The study focused on blood levels of lead, mercury and polychlorinated biphenyls (PCBs). All three pollutants are widespread and are prone to accumulate not just in the environment but also in people's bodies. In addition, all three can cross the placental barrier, can be transmitted through breast milk, and are known to damage the developing brains of fetuses and infants.
Researchers reviewed data on 3,173 women between the ages of 16 and 49 who had participated in the National Health and Nutrition Examination Survey (NHANES) between the years of 1999 and 2004. The survey was designed to comprise a representative sample of the overall U.S. population of women of childbearing age (134.5 million women).
In addition to reviewing participants' body burden of the three pollutants, the researchers also examined a wide range of demographic and health-related information on the women, in an attempt to determine risk factors for higher pollutant levels.
A history of exposure
The researchers found that 55.8 percent of all women had blood levels higher than the median for two or more of the pollutants studied, while almost 23 percent had higher-than-median levels of all three. Only 17.3 percent of women did not have higher-than-median blood levels of any of the three pollutants.
Increased age was the greatest risk factor for having higher-than-median levels of two or more pollutants. Women between the ages of 30 and 39 were 12 times more likely to have such a body burden than women between the ages of 16 and 19, while women between the ages of 40 and 49 were 30 times more likely. Much of this effect can be explained by the fact that all the pollutants studied accumulate in a person's body over time.
"We carry a history of our environmental exposures throughout our lives," lead author Marcella Thompson said.
In addition, Thompson noted, many of the women in the oldest age group were born before the passing of many landmark environmental laws in the early 1970s.
Recent fish consumption and heavy drinking also increased women's risk. Fish are known to accumulate high body burdens of many toxins, so that finding was not surprising. The researchers were unaware of any reason; however, that alcohol consumption might be associated with increased toxin load.
The only factor that decreased a woman's risk was recent breastfeeding - because the pollutants had moved into the breastfeeding child's body instead.
The fact that so many women and their children are exposed to multiple pollutants is especially troubling, because little research has been done on the ways that different pollutants interact in the human body.
"Our research documents the prevalence of women who are exposed to all three of these chemicals," Thompson said. "It points out clearly the need to look at health outcomes for multiple environmental chemical co-exposures."