August 2016 — By Ernie Hood
From three small towns in New York state, to research laboratories around the world and the halls of Congress, perfluorinated chemicals are becoming an increasing concern. Commercial production of perfluorooctanoic acid (PFOA) and perfluorooctane sulfate (PFOS) has been phased out in the United States, yet the chemicals may still pose a threat to the environment and human health (see sidebar).
In July, a National Toxicology Program (NTP) panel of experts peer reviewed a draft report on certain health effects, and NTP scientist Sue Fenton, Ph.D., attended a community meeting in New York, called by members of Congress who represent the towns.
Literature review leads to NTP draft monograph
With a growing body of literature suggesting immune system toxicity, the NTP Office of Health Assessment and Translation was asked in 2014 to evaluate the evidence for an association between exposure to PFOA and PFOS and immune-related health effects, and to determine the immune hazard presented by the chemicals. NTP completed an extensive evaluation of the scientific literature, and on July 19, representatives presented the draft report to a panel of experts for scientific peer review.
“There’s a relatively robust body of evidence [reporting] immune effects for both PFOA and PFOS in experimental animal models,” explained project leader Andrew Rooney, Ph.D. “And then there’s the emergence of a recent body of evidence reporting similar effects on the antibody response in humans.”
“And while PFOA and PFOS share some of the same health effects, there are also some differences,” he added.
Reviewers agree chemicals are presumed to be an immune hazard
The peer review panel voted unanimously to accept the conclusions that both PFOA and PFOS are presumed to be an immune hazard to humans. Presumed hazards are considered to be one step below a known hazard, on the five-step scale NTP uses for hazard identification, from not identified to known to be a hazard.
Both conclusions were based on evidence that these compounds suppress the body’s production of antibodies. Mice exposed to higher levels of PFOA or PFOS produced fewer antibodies when challenged with antigen. Similarly, humans with high levels of either chemical had lower antibody levels to common childhood vaccines.
Additionally, the PFOS conclusion was supported by evidence of suppressed disease response and suppressed natural killer cell activity. Both are hallmarks of adverse immune effects.
Next, NTP will incorporate comments by the peer reviewers into the final monograph, which will be made publicly available.
PFOA on congressional radar
PFOA contamination in the drinking water of three communities near former manufacturing sites in New York led to action by Senators Charles Schumer, D-N.Y., and Kirsten Gillibrand, D-N.Y., and Representative Chris Gibson, R-N.Y. The three leaders sent a letter June 24 to the directors of the Centers for Disease Control and Prevention (CDC) and National Institutes of Health (NIH), asking the agencies to help educate and assist the people of the Village of Hoosick Falls and the Towns of Hoosick and Petersburgh.
“In the last two weeks, hundreds of residents in the Village of Hoosick Falls have received test results showing severely elevated levels of PFOA in their blood samples,” the officials noted in their letter.
Community meetings are being held in the area, and NIEHS is providing info and resources on PFOA and PFOS to congressional staff and communities. Linda Birnbaum, Ph.D., director of NIEHS and NTP, said that the institute continues to fund research by grantees and in-house researchers. “In Fiscal Year 2015, NIEHS obligated approximately $7.3 million for PFOA-related research,” she said.