Back in March, Dr. Tyrone Hayes came to DtaS to speak about the herbicide atrazine. In his studies, he showed an effect on the endocrine system of frogs, leading to reproductive problems. This he said was a possible explanation for the decline in the frog population.

However, Syngenta and other have been unable to replicate his work. The EPA also has been unable to replicate the results. Dr. Hayes has argued these problems stem from using different sets of trial conditions that do not accurately reflect reality.

In any case, studies have been slowly leaking out indicating immuno-disruption by atrazine in various animals. NPR reports on another study just released again pointing at atrazine.

Even though atrazine has been banned in the EU, it is still the 2nd most widely used pesticide here in the US (behind only Roundup). It is mainly used on corn.

There is a new study in Nature on flatworms, called larval trematodes, that seem to show another aspect in frog decline. In a perfect storm of ecological conditions, atrazine seemed to kill off floating algae, which led to greater numbers of floor algae, which led to greater numbers of snails, which carry the flatworms, which then infect the frogs.

It seems as if atrazine has been implicated again in a way that harms frog’s immune systems. According to Dr. Hayes, atrazine only results in a 2-3% increase in corn production. If this is true, why continue atrazine’s use considering the possible negative implications?

All this aside, habitat destruction/climate change is hurting frogs probably to a greater degree.

More Info:
Dr. Hayes on QUEST
Dr. Hayes at DtaS
NPR Report on Frogs
Study on Frog Decline in Nature
Science Friday Interview with Andrew Blaustein

On Science Friday this past week, Holly Ingraham of UCSF was interviewed on her new study of atrazine’s impact on human placental cells. This builds on our conversation with atrazine, starting from March’s discussion on atrazine in frogs. In the study, they showed atrazine (& its metabolized products) increased activity of a gene that results in abnormal baby weight. Also they found amplification of a gene that is highly active in infertile women (no direct association yet).

Science Friday interview with Holly Ingraham

Holly also studied atrazine impacts on zebrafish, a widely used animal in developmental studies. She observed some genetic changes at doses as low as 2 part per billion (EPA’s drinking water limit is 3 ppb). In terms of human effects, she started to see genetic changes at 200 ppb (syngenta called these levels environmentally irrelevant). The chief effect in humans was changing hormone signaling mechanisms, which is fairly significant.

Future studies will focus on how atrazine affects the brain, specifically areas that control metabolism. This will hopefully shed light on why atrazine affects endocrine cells.

A quote from Holly:

These atrazine- sensitive genes are central to normal reproduction and are found in steroid producing tissues. You have to wonder about the long-term effects of exposing the rapidly developing fetus to atrazine or other endocrine disrupters.

Her research was funded by the National Institutes for Health.

Takeaway:

More Info:
Paper in PLoS One
Science Friday chat with Holly
UCSF Press Release on Study
Recent Paper Questioning Reproducibility of Atrazine Effects in Frogs

Check out the piece below. It also indicates how a newly discovered fungus is playing a role in the decline.

And here’s an additional web only piece featuring Tyrone Hayes.

I’m glad he crossed that line…the talk on atrazine was one of the most moving and infuriating I’ve ever attended. In a conversation with Al Gore, Tyrone learned that if two states bring up atrazine legislation, just TWO, open hearings on atrazine at the US congressional level could happen.

Tyrone maintains a website on atrazine: www.atrazinelovers.com

On his website, Tyrone offers a few links to be in action around atrazine.

1. Contact the EPA
Steeger.Thomas@epamail.epa.gov
Schnackenbeck.Joy@epamail.epa.gov
Bradbury.Stephen@epamail.epa.gov
Lindsay.Anne@epamail.epa.gov

2. Write your Congressperson

MN05EllisonKeith@mail.house.gov

This letter is a request urging you and your office to: 1) pursue a ban on the herbicide atrazine as described in Bill H.R. 3399 authored by Representative Keith Ellison, 2) investigate the chemical industry and EPA? collaboration during the review of atrazine as requested by Keith Ellison on June 23, 2007 in a letter to Representative Henry Waxman, Chair of the Committee on Oversight and Government, and 3) to further urge the EPA to develop an effective plan for regulating atrazine and other endocrine disrupting chemicals as requested by Senator Barbara Boxer (Dallas Morning News, Sunday, May 27, 2007).

3. Write Syngenta, the manufacturer of Atrazine

tim.pastoor@syngenta.com
sherry.ford@syngenta.com
michael.vanausdeln@syngenta.com
alan.hosmer@syngenta.com

I urge you to get involved in any of the above ways. You voice can be the difference.

The Presentation (Flash is required)
To move to the next slide, click on the right side of the current slide. Click on the left side to go back.

Videos from the Pesticide event are up on the website. As always, you can watch snippets of the video on YouTube as well.

Atrazine typically has a relatively short half life, about 30 -100 days in soil. It breaks down via chlorination or by microbes to cyanuric acid…which is a carbon and nitrogen source in the soil.

Atrazine is also highly solubilized in water…often traveling into streams, runoff, and rainwater.

Below is a map detailing atrazine use in the US (circa 1997)

So why should I care?…Atrazine has been shown to be a potent endocrine disruptor in animals (at various doses). It has the chemical ability to transform testosterone into estrogen (mainly shown in fish, amphibians, and reptiles). Essentially, it can induce hermaphroditic behavior. It almost goes without saying that this change is devastating, especially to immune system resulting in increased mortality rates (again shown most predominantly in amphibians).

That being said, the EPA maintains the safety of atrazine when used properly and in low concentrations. Syngeta, the manufacturer, also maintains its safety.

I’ll be posting a more detailed analysis of atrazine effects in water. But for now, here are a number of links to more resources.

More Info
Washington Post Article
Dr. Hayes Website on Atrazine
Study of Atrazine effects on Frogs
Union of Concerned Scientists Article
NRDC article
EPA Page
Syngeta’s Atrazine Info Page