Jennifer McPartland, Ph.D., is a Health Scientist.
Today a new study was published linking fetal exposure to certain flame retardants called polybrominated diphenyl ethers (PBDEs) with cognitive and behavioral effects that develop later in childhood. While the specific findings in this study are new, the link between these types of neurodevelopmental effects and exposure to PBDEs is not.
Numerous scientific studies and governmental bodies across the globe have flagged the health effects of PBDEs. At the same time, current proposals by the Environmental Protection Agency (EPA) to better understand the hazards and sources of certain PBDEs remain in limbo. Read on to learn more about today’s new study on PBDEs and the stalling of EPA initiatives to help protect us from exposure to them.
The current study investigated whether in utero (in the womb) exposure to PBDEs resulted in later cognitive and behavior effects in early childhood. To answer this question, researchers sampled and measured PBDE levels in the blood of 309 women at 16 weeks of pregnancy—which approximates the level of PBDEs to which the fetus is exposed. The investigators then followed these children through the age of 5, along the way conducting various clinical tests that examine cognitive and motor abilities, intelligence, and behavior.
The researchers identified deficits in IQ and increased hyperactivity at age 5 associated with higher levels of PBDE exposure experienced in utero, even after taking into account other potential contributors such as maternal IQ, maternal depression, and sociodemographic factors. The authors note certain limitations of their study including not having measures of PBDEs in children’s blood (which can be higher than maternal levels) and not measuring all individual PBDEs of interest. Nevertheless, their findings are consistent with similar epidemiological studies that found associations between PBDE exposure and lower IQ and behavioral disorders (see for example here and here).
Scientists have been highlighting the neurodevelopmental impacts of PBDEs for quite some time. And in a landmark review by Landrigan and Grandjean this year, PBDEs made it onto their list of 12 industrial chemicals with sufficient epidemiological data to be considered known neurodevelopmental toxicants. The review also stresses that 10-15% of all births are now affected by neurodevelopmental disorders and that genetics can perhaps account for only 30-40% of these outcomes.
Rarely do we have the “luxury” of actual human epidemiological data on a chemical. And yet, even with the now-extensive evidence of serious health impacts from PBDE exposures and the significant level of neurodevelopmental disorders in the population, efforts initiated by EPA to better understand and control exposure to PBDEs are moving forward at a snail’s pace.
In 2010, EPA drafted two proposed rules on PBDEs. The first would require anyone intending to begin production, processing or import of any PBDE, or a product containing one, to notify the agency before doing so the risks of the proposed activity can be evaluated and, where necessary, restricted or prohibited. The second would require anyone who continues to produce, process or import any PBDE, or a product containing one, to conduct extensive tests sufficient for EPA to determine the risks posed by those ongoing activities.
These proposed actions were first described in EPA’s 2009 Chemical Action Plan on PBDEs. A year later EPA drafted these proposed rules and delivered them to the White House Office of Information and Regulatory Affairs (OIRA), where they sat for 425 days (note the OIRA review process is supposed to take 90 days). The proposals were finally released for public comment from April 2012 to July 2012. At that time, a bipartisan group of 26 members of Congress urged EPA to take action on toxic flame retardants and to finalize the rules as quickly as possible.
Two years later, there has been not a blip of action or explanation for the delay.
Nearly five years have passed since EPA first proposed these modest actions in its PBDE chemical action plan. Perhaps it’s wishful thinking, but here’s hoping that today’s study inspires and motivates EPA to get these proposals to the finish line.