In the spotlight he craves once again, activist-scientist Tyrone Hayes released yet another study this week online in the Proceedings of the National Academy of Sciences (PNAS) on the effects of the herbicide atrazine on frogs. The USA Today online article referencing the study can be found at http://www.usatoday.com/tech/science/2010-03-02-1Aatrazine02_ST_N.htm

It doesn’t appear that his flair for the dramatic has been replaced with the rigors of science in his latest work. Once again, you can expect many errors of fact, inaccurate citations of the scientific literature, and a failure to cite the extensive body of scientific evidence that would undermine his thesis.

It should be noted that Dr. Hayes’ previous work has been repeatedly and exhaustively examined by governmental regulatory agencies as well as independent scientists and found to not stand up to rigorous scientific scrutiny.

This would not be the first time Tyrone Hayes has published studies in a scientific journal which, upon investigation, have proven to be unreliable. After an exhaustive investigation into Hayes’ earlier studies, EPA published a 95-page white paper concluding that his study and other studies he cites are “scientifically flawed.” In reference to Hayes’ earlier studies, the former Deputy Director of EPA’s Office of Pesticide Programs, Anne E. Lindsay, testified in 2005 that Dr. Hayes’ “data are insufficient” to support what he claimed to have found.

EPA further complained that Dr. Hayes would not share his raw data: “[EPA] has never seen either the results from any independent investigator published in peer-reviewed scientific journals or the raw data from Dr. Hayes’ additional experiments that confirm Dr. Hayes’ conclusions.”

In response to Hayes’ earlier allegations, however, the registrants conducted two, massive, state-of-the-art studies, based on newly developed EPA guidance. Every detail and raw data point of those studies were audited and inspected by the EPA. Both studies clearly and convincingly debunked the claims leveled by Dr. Hayes.

The PNAS Report contains two serious flaws that undercut its credibility: 1) the use of only one dose level of atrazine, when almost all studies used to assess the effects of substances for regulatory purposes are conducted at more than one concentration and 2) the failure to use a positive control — a basic requirement of this kind of study.

Hayes repeatedly cites other researchers incorrectly, distorting their findings in order to bolster his own claims. Hayes completely misrepresents the findings of Carr et al (2003) as supporting his thesis. They do not. On the other hand, Hayes fails to cite other studies, such as those conducted by DuPreez et al, that do not support his findings — something a reputable scientist would do. In fact, the DuPreez studies flatly contradict Hayes’s claims.

Perhaps most notable is that Hayes new claims are inconsistent with his previous work. For both Hayes’ earlier and current claims to be true would be a physiological impossibility. Either his current study discredits his previous work or his previous work discredits this study.

Furthermore, it should be noted that Tyrone Hayes has declared himself an activist and aggressively campaigns for the banning of the herbicide atrazine. As such, the degree of scientific objectivity one normally expects in such publications is suspect. The fact that he is now using the NRDC to promote his study highlights the political nature of Dr. Hayes’ attacks.

Finally, the manner in which Dr. Hayes conducts himself has caused some to seriously question the soundness of his judgment. In 2009, in fact, Dr. Hayes statements and actions were so extreme that a member of the Society of Environmental Toxicology and Chemistry asked that Hayes be censured for his “inflammatory and libelous attacks,” adding that Dr. Hayes “demonstrate[d] that it is okay to present provocative conclusions without supporting data.”

Apart from all its flaws, if considered at all, this study must be considered in the context of the massive number of studies that have shown atrazine to be safe to use. Authorities around the globe have found no link between atrazine exposure and adverse health effects. The EPA, the Australian government, and the World Health Organization have all looked at atrazine’s effects on endocrine systems and given atrazine a clean bill of health.

The EPA estimates pulling atrazine from the shelves would cost corn growers $28 an acre in lost yields and substitutes, and the total negative impact on American agriculture would exceed over $2 billion per year.

Farmers and farm organizations across the United States have worked together on the issue of atrazine for 15 years, providing <a href="http://atrazine.blogspot.com/">atrazine news</a>, including recent coverage of <a href="http://atrazine.blogspot.com/2010/03/tyrone-hayes-back-in-spotlight-again.html">atrazine and frogs</a>, and assuring crop protection decisions are based on science, not politics.