September 30, 2019

Perfluoroalkyl compounds (PFAs) have become notorious global contaminants


PFAs were detected in water sources serving more than 7 million Californians, according to a new report* by the Environmental Working Group. EWG describes itself as "dedicated to protecting human health and the environment.” It reports finding PFA contamination in water sources for 74 community drinking water systems -- serving 7.5 million people in California.

Unlike other global contaminants such as lead (Pb) and other metals, PFAs have upended the environmental regulatory world.  Regulatory agencies usually have found that control to parts per billion (ppb) or parts per million (ppm) will protect public health reliably and adequately.  The drinking water standard for Pb, for example, is 15 ppb.  PFAs, however, exhibit potent toxicological effects in the usually-unregulated parts-per-trillion (ppt) range, posing new challenges for environmental monitoring and regulation.

These challenges posed by the disturbing toxicology and environmental dynamics of PFAs have been examined by Dr. Robert A. Michaels in two articles recently published in the Environmental Claims Journal. Michaels (2017; see below) addresses massive PFA contamination of drinking water and other  environmental media in Hoosick Falls, Rensselaer County, New York. This episode of corporate environmental impact has garnered national attention because it adversely affected the health of people and the market value of their homes. Michaels (2018; see below) critiques the New York State Health Department's cancer cluster study in Hoosick Falls. He finds major shortcomings, some particular to the study and others applying to cancer cluster studies generally.

Most notably, standard operating procedure in science requires application of the stringent p ≤0.05 confidence criterion of statistical significance.  The Health Department study, like other cancer cluster studies, used this standard inappropriately to confirm cancer clusters in Hoosick Falls.  Unsurprisingly, it found none related to PFAs.  Use of the p ≤0.05 confidence level is aimed at conservatively protecting the body of scientific knowledge.  As a trade-off, however, it may confuse real cancer clusters with statistical flukes, justifying ignoring them.  Consequently, the standard procedure may fail to protect public health conservatively.

Michaels (2018) and Michaels (2017) both are available for download at no charge via the following URL links:

Michaels (2018):

Michaels (2017): 

Please direct questions or comments concerning this post, and/or Michaels (2018), and/or Michaels (2017) to Dr. Michaels at ram@ramtrac.com.

* See https://www.cnn.com/2019/09/27/us/pfas-california-contamination-trnd/index.html