Expert Commentary

Chemical exposures to lead, mercury and PCBs among childbearing-aged women

2012 study from Brown University and the University of Rhode Island on the body burden and risk factors for U.S. women of child-bearing age.

Pregnant woman standing in field (iStock)

Living in an industrial society has its advantages, including abundant food, endless consumer goods and speedy transportation options (assuming one can afford it all). But while some risks can be minimized, it’s much harder to escape the environmental pollution that results from activities such as automobile use, and even seemingly innocuous products can be rife with industrial additives.

Mercury, PCBs and lead are known to have a negative impact on human health and development, but less is know about consequences of exposure to two or three of them simultaneously. A 2012 study published in Environmental Research, “Multiple Environmental Chemical Exposures to Lead, Mercury and Polychlorinated Biphenyls Among Childbearing-Aged Women,” looked at women aged 16 to 49 whose levels of exposure to all three substances were at or above average. In the study, the chemicals are collectively referred to as “xenobiotics” — substances found in the body that it doesn’t produce or that wouldn’t be expected to be present.

The researchers, at Brown University and the University of Rhode Island, based their research on analysis of the National Health and Nutrition Examination Survey (1999-2004). In all, 3,173 women were included in the study.

The findings include:

  • More than 20% of the women examined had levels of lead, mercury, and PCBs at or above average. “Among the 33% of women who had two xenobiotic levels at or above the median, it was as likely to be PCBs-lead (36%), mercury-lead (34%) or mercury-PCBs (29%). Among the 27% of women having only one xenobiotic level at or above the median, it was as likely to be lead (43%), mercury (36%) or PCBs (21%).”
  • “Consuming fish more than once per week quadrupled the odds of having two or more xenobiotic levels at or above the median when compared to those women who had no fish consumption during this same time period. Fish consumption correlated significantly to mercury-PCB exposures.”
  • Heavy alcohol consumption raised the likelihood of having two or more xenobiotic levels at or above the median.
  • Women who had breastfed at least one child for a month or more were 44% less likely to have two or more xenobiotic levels at or above the median than those who had never breastfed. On the other hand, “current breastfeeding tended to increase the odds of these women having two or more xenobiotics at or above the median, however this relationship was not [statistically] significant.”
  • The odds of having two or more xenobiotic levels at or above the median rose exponentially with age. The oldest subset of women (aged 40–49) had a markedly higher risk than younger groups.
  • Some evidence was found of increased risk among minority women independent of other risk factors.

“The findings of this study should be used to inform healthcare practitioners and environmental health professionals of the widespread prevalence of childbearing-aged women’s exposure to lead, mercury and PCBs,” the researchers state in conclusion. “Emphasis should be placed on bioaccumulation, maternal exposures and intergenerational transfers during gestation and lactation.” The researchers also suggest that a “balanced approach” be taken when communicating the risks and benefits of fish consumption as well as breastfeeding.

Keywords: children, parenting, pollution, neurotoxins, pregnancy, pregnant, body burden, plastics

About The Author