Environmental Factor, February 2011, National Institute of Environmental Health Sciences
Environmental toxicants transfer from mother to baby
According to Grandjean, almost all of the 87 chemicals were detected in both maternal and fetal tissues. (Photo courtesy of Philippe Grandjean)
The late Larry Needham headed environmental exposure measurements at the CDC and was an international leader in exposure assessment methods. (Photo courtesy of Philippe Grandjean)
A new NIEHS-funded study has quantified for the first time the large number of environmental chemicals transferred to baby from the mother's cumulative exposure. An international team of scientists led by grantee(http://tools.niehs.nih.gov/portfolio/index.cfm?action=portfolio.grantdetail&grant_number=R01ES012199) Philippe Grandjean, M.D., Ph.D., an adjunct professor of Environmental Health at the Harvard University School of Public Health, measured concentrations of 87 environmental chemicals in both maternal and fetal tissues.
The findings of the study(http://www.ncbi.nlm.nih.gov/pubmed/21166449) support the premise that pregnant and lactating mothers transfer environmental contaminants to their children, with possible risks of impairing neurological, reproductive, immunological, respiratory, and metabolic development. The team calculated partition ratios in regard to maternal serum concentrations for concentrations in maternal milk and fetal tissues. In general, a high degree of correlation was found between concentrations in maternal serum and other tissues, although the ratios differed between types of samples.
Grandjean(http://www.hsph.harvard.edu/faculty/philippe-grandjean/) and his colleagues were able to identify complex patterns that may help researchers pinpoint the most representative, easily obtainable samples for analyzing concentrations of specific trace elements and other compounds. As the authors cautioned in their conclusion, "These patterns are complex, and the complexity must be taken into account when selecting samples for analysis and when interpreting results."
In a Jan. 5 article(http://pubs.acs.org/iapps/wld/cen/results.html?line3=%22Pollutants%27+Passage+From+Mother+To+Child%22&x=0&y=0) about the study in Chemical and Engineering News, Linda Birnbaum, Ph.D.(http://www.niehs.nih.gov/about/od/director/index.cfm), NIEHS/NTP director, stressed that further studies are needed because these compounds, especially some low molecular weight polychlorinated biphenyls (PCBs), can easily cross the human placenta barrier to cord blood and milk. Lynn Goldman, M.D.(http://faculty.jhsph.edu/default.cfm?faculty_id=912) , dean of the George Washington University School of Public Health and Health Services, recommended policymakers consider the study's findings when limiting women's exposure to compounds that can potentially harm their offspring.
Telling results in a highly exposed population
To obtain systematic data about the correlation between sample types from the mother and baby, the researchers examined 15 complete sample sets of maternal and cord blood, cord tissue, placenta, and milk in connection with normal births in a fishing community of the Faroe Islands, located between Norway and Iceland. They selected this area, in part, because of the anticipated elevated exposure to marine contaminants among residents whose traditional diet includes pilot whale meat and blubber, which contain high levels of persistent pollutants such as methylmercury and polychlorinated biphenyls (PCBs).
Among their results, the researchers report that the concentration of organohalogen compounds used in solvents, refrigerants, and pesticides in a mother's blood is highly correlated to levels in her developing baby. The team also examined correlations for the trace elements mercury, cadmium, lead, and selenium, as well several common congeners, or forms, of perfluorinated compounds (PFCs), PCBs, polybrominated diphenyl ethers (PBDEs), and other compounds.
PFCs, which are highly resistant to breakdown and are turning up in unexpected places around the world, are widely used in stain-resistant and grease-repellent products. PBDEs are persistent and bioaccumulative industrial chemicals used as fire retardants in a wide array of products. Results from this study and ongoing investigations will help regulators identify what compounds are potentially hazardous to unborn and nursing babies, as well as determine whether reduction in organohalogen compound exposure limits are warranted.
Results from this study and ongoing investigations will help regulators to identify what compounds are potentially hazardous to unborn and nursing babies, as well as to determine whether downward revisions of organohalogen compounds exposure limits are warranted.
Scientists from Germany, Denmark, and the Faroe Islands participated in the study with Grandjean and researchers from the U.S. Centers for Disease Control and Prevention (CDC), who included the veteran CDC chemist and first author on the study, Larry Needham, Ph.D.(http://www.legacy.com/obituaries/tennessean/obituary.aspx?n=larry-lewis-needham&pid=146373454) , who died before the findings were published online. In the corresponding author section of the study, the authors acknowledge his passing and write, "He will be missed both as a colleague and a friend."
Citation: Needham LL, Grandjean P, Heinzow B, J��rgensen PJ, Nielsen F, Patterson DG, Sj��din A, Turner WE, Weihe P.(http://www.ncbi.nlm.nih.gov/pubmed/21166449) 2010. Partition of Environmental Chemicals between Maternal and Fetal Blood and Tissues. Environ Sci Technol; Doi:10.1021/es1019614 [online 17 December 2010].
(Emily Zhou, Ph.D., is a research fellow in the NIEHS Laboratory of Signal Transduction Inositol Signaling Group.)