Chemical Pollution in Your Backyard: Researching the Effects of Endocrine Disruptors in Suburbia

We were so pleased to receive this guest post by Geoffrey Giller, who is a Master’s of Environmental Science candidate, 2013, at the Yale School of Forestry and Environmental Sciences. At Frogs Are Green, we have explored the issue of endocrine disruptors and their possible effects on frogs, as well as on humans. We look forward to learning the results of his research.

Geoffrey Giller environmental sciences Yale school

Geoff Giller readying nets for sampling at a golf course (Photo credit: Susan Bolden)

Frogs are threatened globally by a host of stressors, from habitat loss to climate change to infectious diseases. One threat receiving increased scientific attention is endocrine-disrupting chemicals (EDCs). These chemicals interfere with normal hormonal function. In 2002, Dr. Tyrone Hayes published a paper in Nature detailing the feminizing effects of the widely-used pesticide atrazine on male African clawed frogs. Since then, there has been increasing research showing similar effects of other EDCs on frogs and fish. There is also more and more evidence that endocrine disruptors are widely prevalent pollutants in the water bodies of the United States.

As a Master’s student at Yale’s School of Forestry and Environmental Studies, I want to further investigate the presence and effects of these EDCs. My advisor, Dr. David Skelly, recently published a paper showing that green frog hermaphrodites are most prevalent in suburban areas. While most research since Dr. Hayes’ paper has focused on agricultural areas, Dr. Skelly’s work indicated that there may be a significant source of EDCs causing these high rates of hermaphroditism (as demonstrated by the presence of egg cells in the gonads of male green frogs) in suburban areas.

photomicrographic frog cells

Testicular oocytes (egg cells in male gonads) from Skelly et al. 2010

This topic has implications both for frog conservation, as such sexual deformities likely inhibit frogs’ abilities to reproduce, and for human health, since suburban areas are much more densely populated than agricultural ones. But while the presence of these deformities has been confirmed, their cause has not. Dr. Skelly has hypothesized that the cause may be certain EDCs called synthetic estrogenic compounds; these chemicals are found in medications such as birth control pills as well as in some cosmetic products. The source of these chemicals would likely be septic tanks that leach chemicals into the groundwater; this contaminated groundwater then flows into nearby ponds, streams, and wetlands where frogs breed and live.

I am working with my fellow Master’s student, Max Lambert, to identify exactly what chemicals are present in the groundwater and pond water in suburban areas and what effect these chemicals are having on frogs. In collaboration with scientists at USGS, we will be installing sampling devices at 9 suburban sites, as well as three agricultural and three forested sites as comparisons. We will sample the groundwater and the pond water for a large range of chemicals including medications, synthetic estrogens, pesticides, and a host of other man-made compounds. This study will provide a list of the chemicals that may be responsible for the deformities in the frogs that we are observing.

Small Frog size of fingernail

Max Lambert with a peeper (Photo credit: Hannah Erin Bement)

In addition to the water testing, we will be surveying three types of frogs—American toads, gray tree frogs, and pickerel frogs—for similar sexual deformities. By combining the data from our water testing with the rates of deformities in frogs at these same ponds, we will be able to say which chemicals are likely causing deformities, and which are not. This information will be crucial for the future regulation of these chemicals.

The main stumbling block of this project is the cost. EDCs can have significant biological effects when present at very low concentrations; however, doing water testing for such low concentrations of chemicals requires highly specialized equipment. While some of our costs are covered by our collaboration with USGS, we still need to raise some funds. For more information on our project, and for a chance to help us out with this research, please go here: http://www.petridish.org/projects/estrogens-in-your-backyard-the-chemical-ecology-of-suburbia. This website allows researchers to raise necessary resources through “crowdfunding,” or multiple small donations from a large number of people. We are close to our target funding amount, but could use a little more help. Take a look at our page (as well as the various rewards for different donation amounts), and we would be incredibly grateful for your support!


A Field of Nightmares Updated: Atrazine, Corn, and Frogs

As Susan and I are hosting family and friends, we are reposting a couple of posts this week from the past year. We’ve updated this post with new material below. This post originally ran in January 2010.

I’ve always had a sentimental attachment to cornfields—from the magical cornfield in Field of Dreams to the real cornfield across the road from a house I lived in during college years. My mother was born and raised in Iowa and I’m descended from Iowan farmers.


But chemicals, in particular Atrazine, used as herbicides on cornfields might be poisoning frogs (and people), and turning fields of dreams into fields of nightmares.  These herbicides run off cornfields into streams and rivers, and leak through the water-treatment process, contaminating groundwater and drinking-water supplies.

Last summer we blogged about the problems of Atrazine. Research by University of California, Berkeley professor  Dr. Tyrone Hayes, for example, has shown the effects this chemical—an endrocrine disruptor—has on frogs. It can cause birth defects and reproductive problems, including such bizarre deformities as male frogs with eggs in their testes. As reported in the Washington Post, new research at the University of Ottawa found that when exposed to Atrazine fewer tadpoles reached froglet stage. Atrazine appears to affect estrogen in humans as well and has been connected with ferility problems, cancer, and birth defects.

Warning in a Cornfield Warning in a Cornfield

The EPA, under the Obama administration, has launched a review of the chemical that will continue until fall 2010. It will look closely at Atrazine and other endrocrine disruptors, which might result in tighter restrictions on their use. While this sounds hopeful, Atrazine’s primary manufacturer, Syngenta, has strong ties and influence within the EPA. (Atrazine is banned in Europe, where perhaps industry and government aren’t as closely intertwined as they are in the U.S.).

For more information, please see this PDF,  a report by the Land Stewardship Project and the Pesticide Action Network North America titled The Syngenta Corporation: The Cost to the Land, People, and Democracy.

Update 8/10: Save the Frogs is sponsoring the International Day of Pesticide Action, in Washington, DC, on October 24, 2010, a march through the streets of DC from the steps of the Capitol to the Environmental Protection Agency demanding a federal ban on Atrazine, the 21st Century’s DDT. Please visit the Save the Frogs site for more information and to sign a petition to get Atrazine banned.  (Note: Susan designed the logo below)


Frogs in the Classroom: Books and DVDs

School is just around the corner, so we’ve put together some recent books and DVDs about our amphibian friends that you, your students, or your kids might enjoy. The descriptions are from Amazon or from the publishers’ websites.

Books for Kids

Face to Face with Frogs by Mark Moffet. (National Geographic, 2008). 32 pgs. 4-8.

You’re two inches away from a poison dart frog. You’re lying on the rainforest floor as she hops toward you, utterly fearless. This deadly terribilis frog has nothing to fear; your fear is that any accidental contact with your skin could mean death! Let Mark W. Moffett, winner of the 2006 Lowell Thomas Medal for Exploration, show you around the diverse world of frogs.


Frogs by Nic Bishop (Scholastic Nonfiction, 2008). Ages 7-11, 48 pages.

For the first- to third-grade set, frogs are an endless source of fascination, especially when looked at VERY close up. See tiny poison dart frogs and mammoth bullfrogs, as Nic Bishop’s amazing images show the beauty and diversity of frogs from around the globe.


The Frog Scientist (Scientist in the Field Series), by Pamela S. Turner and Andy Comins (Houghton Mifflin, July 2009) 64 pages, ages 9-12

This Scientists in the Field title is about frog scientist Dr. Tyrone Hayes, who has explored the effects that pesticides, particularly atrazine, have on frogs and, in turn, on us.

This summer we did a post on Dr. Tyrone Hayes. With Atrazine in the news just this week, I hope we will continue hear a lot more from Dr. Hayes.


Books for High School Students and Above

Extinction in Our Times: Global Amphibian Decline, by James P. Collins and Martha L. Crump, introduction by Thomas E. Lovejoy III (Oxford University Press, June 2009).

The first book to fully examine the dramatic, ongoing extinction of amphibian species across a whole vertebrate class, revealing what it may portend for the health of the planet. Joining scientific rigor and vivid storytelling, this book uses amphibian decline as a lens through which to see more clearly the larger story of climate change, conservation of biodiversity, and a host of profoundly important ecological, evolutionary, ethical, philosophical, and sociological issues.


We have ordered this brand new book, published this summer, and are looking forward to reading it.


Nature Frogs: The Thin Green Line, PBS DVD

Frogs have been hopping the planet for more than 350 million years; evolving into some of the most wondrous, diverse and beloved animals on earth. Suddenly, they’re slipping away. Some say it’s the greatest extinction since the dinosaurs. Ecosystems are beginning to unravel and medical cures are vanishing. It’s a global crisis, mobilizing scientists around the world to stem the tide, before the next frog crosses the thin green line.

We watched this show online on the PBS website—it’s well worth watching. This DVD would be great for a high school biology, environmental science, or social studies class.

Occasionally blog readers send us their products to review. We received a DVD called Danni’s Tales written and directed by Allen Plone and produced by Damon Cohen. This innovative series combines live action with animation. The show is set in a classroom where Danni Donkey introduces her students to special friends while they travel around the world, enjoying music, dance, and learning about the world’s animals and the environment.

We watched a few of the shows, and we think they will delight children. Each show features a different animal—frogs, bears, whales, and others. They are fun, quirky, and educational—the songs are catchy and clever. Take a look at their website, where you can play clips of the episodes.



Frog Scientist: Dr. Tyrone Hayes and Atrazine

In my post Rachel Carson’s Legacy, I wrote about widely-used chemicals called endocrine disruptors that are causing deformities in fish and frogs, and are linked to an increase in genital deformities in newborn baby boys.

When reading about endocrine disruptors, I keep coming across the work of Dr. Tyrone Hayes, a professor in the Department of Integrative Biology, at the University of California–Berkeley. He has studied the effects on frogs of an agricultural pesticide called Atrazine. Hayes found that these chemicals, even at very low levels, were causing male frogs in the wild to develop eggs in their testes (!).

I came across a lecture Dr. Hayes gave called “From ‘Silent Spring’ to Silent Night.” The lecture is about an hour long, but it’s worth watching (see below). Hayes is a funny and engaging speaker and he uses easily understood charts/graphs/pictures to explain how these chemicals effect the frogs—and how they might also effect you.

One Dr. Hayes’s experiments with frogs really hit home with me. He studied two groups of frogs that live along the same river in California. For the experiment he placed the frogs, same species, in cages in the water. One group was placed upstream of the Salinas valley, one of the largest agricultural areas of the country, which is farmed intensely all year round. Runoff containing Atrazine and other chemicals from the farms flows into the river.

The other group of frogs was placed about 50 miles downstream in a clean area. He found that the tadpoles in the area near the farms had retarded growth. They were tiny compared to the frogs in the healthier area. Hayes then injected both groups of frogs with bread yeast. The group of frogs near the farms died within a day or two after being injected with the yeast. The other frogs, from the cleaner area upstream of the agricultural area, survived. They were larger and had stronger immune systems and so were able to fight off the effects of the yeast.

I am not a scientist, but it does make me wonder about claims that some scientists make that the various viruses, parasites, and even the recent claim that frog deformities are caused by dragonfly larvae, are “part of nature.” The frogs living in the “chemical soup” obviously were smaller, weaker, and more susceptible to parasites and diseases.

As Hayes says, we can’t just pass this off as a frog problem that isn’t relevant to humans. Our hormones are chemically identical to frog hormones. Hayes discusses studies indicating higher breast cancer rates in areas where Atrazine is in the well water. He points out that the effects of the chemical may not be obvious now, but may be carried to our children, grandchildren, and even great-grandchildren.

How can you reduce your own exposure to Atrazine? If you live in the Midwest or other agricultural areas, you might consider drinking bottled water or use a Brita filter on tap water, particularly if you are pregnant. The runoff from farms is at its worst from May to August (in the Midwest). As Elizabeth Royte writes in her book Bottlemania: How Water Went on Sale and How We Buy It:

Human kidneys filter Atrazine, and most people don’t spend a lot of time swimming in herbicide-laced water as frogs do. But human fetuses do.

I was surprised to learn that Atrazine is sprayed on Christmas trees as well.

Below are two videos. The first is Hayes’s hour-long lecture “From ‘Silent Spring’ to Silent Night.” Under this video is his “Atrazine Rap,” a 2-minute summary of the lecture in case you don’t have time to watch the longer video.