Atrazine Effect

Atrazine’s Impact on Frogs

Atrazine is the most common herbicide used by farmers all over the world to destroy weeds. It is most widely used on corn in the U.S., especially in the Midwest. However, atrazine has been proven to have many side effects which include contamination of the ground and surface water, and reproductive changes in fish, amphibians, reptiles and human cell lines due to its role as a strong endocrine disruptor (Graymore et al, 2001). The present study aims to find out the reproductive consequences of atrazine exposure in male African clawed frogs (Xenopus laevis). The authors’ hypothesis is that atrazine-exposed male frogs might show demasculinization symptoms such as low testosterone levels and decreased fertility (Hayes

It was found that the atrazine-treated males suffered from gonadal dysgenesis(underdeveloped testes with poorly structured, closed or absent lobules and low to absent germ cells). Some of them displayed sex reversal and testicular oocytes were found in these animals, which turned out to be hermaphrodites (Hayes et al, 2003). The most sensational finding of the current study was that the hermaphroditism observed at metamorphosis can ultimately result in complete feminization (Hayes et al, 2010). This technique has been used before, in previous studies done on zebra fish and leopard frogs. However, this is the first time that such research has been conducted on African clawed frogs, and the result led to a new discovery.

In the current study, researchers compared 40 male control frogs with 40 male frogs reared in high atrazine concentrations from the moment they were born until full sexual maturity was accomplished. The concentration of atrazine was similar to what animals actually experience in areas where this herbicide is used by farmers. After they had all reached adulthood, the frogs were tested in the lab for reproductive consequences. The data collected was empirical in nature, by means of observation (Hayes et al,

The remaining 10% of frogs developed into females who were capable of reproduction. Although the authors’ hypothesis about demasculinization of frogs was right, they were still surprised by the second part of their research which showed that the frogs underwent complete feminization. The author also suggests that further experiments should be conducted to understand why only certain atrazine-exposed male frogs become females and if this particular trait is heritable (Hayes et al,