Atrazine and Amphibians

 

            Atrazine – or 2-chloro-4-6-s-triazine – is one of the most widely used herbicides in the continental United States (1). Since its introduction in 1959 (2), farmers have been applying atrazine to prevent the growth of weedy grasses and broadleaved plants. Currently over 27 000 tonnes is applied annually to corn, sorghum and sugar cane (1). And that is fine, because it only kills weeds… right?

Well, in 2002, Dr. Tyrone Hayes of UC Berkeley published a study investigating atrazine’s effects upon amphibian development. Both in the lab as well as at atrazine-contaminated sites throughout the US, he found that frogs exposed to atrazine developed abnormal gonads (3). In many cases, both male and female reproductive organs were present on the same frog!

 His findings lead to widespread public outcry and concern, as well as calls for more studies to be conducted. Over the past ten years, Dr. Hayes has published ten more studies all with similar findings: that atrazine disrupts the endocrine system of amphibians, reptiles and fish and can result in males developing female reproductive parts (4).

On the other hand, Syngenta – the company that sells atrazine in the United States – conducted several studies of their own, and in every one concluded that atrazine had no effect upon amphibian development (5).

So… who is correct? Does atrazine affect frogs as Dr. Hayes found, or is Syngenta right in that atrazine is harmless?

However in

I think this is a quandary worthy of discussion: Should a company study the health and environmental impacts of their own products, at the risk of their findings negatively affecting their own profit margin? Or if you trust the findings of Syngenta, how did Dr. Hayes’ find what he did in the first place?

How do we know which studies to believe?

As scientists, what we believe should be irrelevant to our decision making; it should be what we think. But what are we to think about this issue when the ‘truth’ is so unclear?

I suppose the next question we should ask is, do we care about the effect of atrazine upon amphibian species, or do we spend our time and money upon a less controversial issue? On one hand, the prevalence of use of this herbicide means any impact it has would be massive and widespread. But on the other hand, if it were not used, food would likely cost a fair bit more (6).

So what do we choose – the science of Syngenta or the findings of Dr. Hayes? Do we try to save the amphibians or continue to have cheap food with a side helping of atrazine?

On a side note, the EU has not allowed the use of atrazine in their food system.

1.    U.S. Environmental Protection Agency. 2013. Atrazine Updates. Available from http://www.epa.gov/opp00001/reregistration/atrazine/atrazine_update.htm
2.      AGsense. 2013. Atrazine Regulatory Issues. Available from http://agsense.org/atrazine-regulatory-issues
3.      Nature. 2002. Feminization of male frogs in the wild. Available from http://www.nature.com/news/2002/021031/full/news021028-7.html
4.      Web of Knowledge. 2013. Web of Science. Available from http://apps.webofknowledge.com.ezproxy.tru.ca/summary.do?SID=2C3kGDLp35gO7E8k535&product=WOS&qid=2&search_mode=GeneralSearch
5.      AGsense. 2013. Atrazine and Frogs. Available from http://agsense.org/atrazine-regulatory-issues/atrazine-and-frogs/
6. Ackerman F. 2007. The Economics of Atrazine. Int J Occup Environ Health. 13:441-449.

 

Plants in Peril...?

Rosy Owl-Clover (Orthocarpus bracteosus) – A Red-listed species native to BC's west coast. I saw a very similar species this summer while working in the East Kootneys. Plants are only 20 cm tall and their flowers are a brilliant pink – the most brilliant color I have ever seen in a wildflower!!

Image source: http://linnet.geog.ubc.ca/ShowDBImage/ShowStandard.aspx?index=5885

As I was looking through the Habitat Conservation Trust Foundation’s list of funded projects (HCTF 2012), I was struck by how very few dealt with plants. From the HCTF, people have received funding to enhance the habitat of Lytton elk, maintain salmon and trout spawning channels, restore western painted turtle habitat, and prevent rattlesnakes from entering human-inhabited areas. Other funded projects aim to identify the bat species present during the winter in Southern BC while more still plan to determine population sizes for BC’s steelhead and sturgeon fish, grizzly bears in the Stein valley, and goats in the Shuswap region. And while I agree with the need and idea behind many of these projects, I cannot help but wonder – what about the plants?

            In BC, there are over 1100 species and subspecies of plants that are either red or blue listed (BC Ministry of Environment, 2013). That is, in BC alone there are over 1100 plant species that are endangered, extinct, extirpated, of special concern, or are threatened. Comparatively, there are only 400 animals in to BC that fall into these five categories (BC Ministry of Environment, 2013).

            Despite the overwhelming numbers of red and blue-listed plants, all of the projects I saw on the HCTF's website focus upon the “habitat protection” of various animals (HCTF 2012). Nowhere did I find a project with the purpose of protecting a specific endangered plant species. And while protecting the habitat of other animals does in turn protect the plant species that live there, I cannot help but wonder if we are making a mistake by not explicitly protecting our threatened plant species. I mean, it isn’t like plants are entirely useless – all animals (including ourselves) depend upon plants to provide us with oxygen to breathe, food to eat, material to make shelter of as well as to maintain countless other ecosystems services.

            I suppose the point I am trying to make in writing this blog post is thus: Given that there are almost three times as many endangered plant species than there are animals of concern in BC, is it a good idea to focus only upon these animals and not on the plants that all animals depend on? That is, if we forget to protect the plants, where will it leave the animals?

BC Ministry of Environment. 2013. Plants & animals search results [Red & blue list] - BC Species and Ecosystems Explorer. BC Ministry of Environment, BC. Available from http://a100.gov.bc.ca/pub/eswp/search.do?method=process&searchType=COMBINED&bcList=Red&bcList=Blue (accessed January 15 2013).

Habitat Conservation Trust Foundation (HCTF). 2012. Approved project list 2012-2012. HCTF, BC. Available from http://www.hctf.ca/News/newsrelease/APPROVED%20HCTF%20PROJECT%20LIST%202012-13.pdf (accessed January 15 2013).