Herbicide Turns Male Frogs to Females
The research was led by Dr. Tyrone Hayes, a biology professor at Berkeley. Dr. Hayes has been studying the effects of this herbicide for over a decade.
Atrazine – ethylaminoisopropylaminotriazine – is the second-most popular herbicide after glyphosphate (Roundup). It is used on about 90% of sugarcane crops and about half of the corn grown in the U.S.
Dr. Hayes’ research began under the funding of Atrazine’s then-owner, Novartis in 1997. Dr. Hayes found that frogs exposed to 1/30th of the amount the EPA allows in our drinking water shrunk the voice boxes of frogs.
After his resignation from the research team, Dr. Hayes continued his research, and found that when frogs are exposed to levels of Atrazine at levels close to what is allowed by the EPA in drinking water – which is often exceeded – male frogs began to produce less testosterone and more estrogen. Over time, the frogs, exposed to 25 parts per billion, began to show signs of demasculinity.
Levels of Atrazine in runoff waters from agriculture have been known to reach 40 parts per billion.
After ten years of additional research, together with a team of scientists, Dr. Hayes established – using rigorous protocols – that male frogs, fish and reptiles all became demasculinized after exposure to Atrazine. After conclusive and extensive research, the research team concluded that:
“Atrazine demasculinizes male gonads producing testicular lesions associated with reduced germ cell numbers in teleost fish, amphibians, reptiles, and mammals, and induces partial and/or complete feminization in fish, amphibians, and reptiles.”
Are we exposed to Atrazine?
A 2009 investigation by the New York Times revealed that 33 million Americans have Atrazine in their drinking water. 2010 EPA data reveals contamination levels exceeding the federal limit in nine of ten states that monitor Atrazine levels. And a number of water districts in the Midwest have reported nine to 18 times the limit in their water supplies.
This – Atrazine contaminating water supplies – is one of the reasons that the European Union banned Atrazine in 2003.
Epidemiological studies have found that prenatal Atrazine exposure is linked to birth defects and preemie babies, even when exposure levels are low.
An EPA advisory panel on Atrazine characterized this epidemiological evidence as “strong” last July.
Investigations by the Huffington Post found that over half of the papers the EPA has relied on to approve Atrazine’s use were those from researchers with a financial interest in Atrazine, while less than 20% of the research was peer-reviewed.
Hayes TB, Anderson LL, Beasley VR, de Solla SR, Iguchi T, Ingraham H, Kestemont P, Kniewald J, Kniewald Z, Langlois VS, Luque EH, McCoy KA, Muñoz-de-Toro M, Oka T, Oliveira CA, Orton F, Ruby S, Suzawa M, Tavera-Mendoza LE, Trudeau VL, Victor-Costa AB, Willingham E. Demasculinization and feminization of male gonads by Atrazine: consistent effects across vertebrate classes. J Steroid Biochem Mol Biol. 2011 Oct;127(1-2):64-73.
Slater D. The Frog of War. Mother Jones Magazine. 2012. Jan/Feb.
Hayes TB, Collins A, Lee M, Mendoza M, Noriega N, Stuart AA, Vonk A. Hermaphroditic, demasculinized frogs after exposure to the herbicide Atrazine at low ecologically relevant doses. Proc Natl Acad Sci U S A. 2002 Apr 16;99(8):5476-80.