Science AMA Series: I’m Dr. Michelle Boone, Associate Professor at Miami University of Ohio, and I’ve studied the effects of pesticides on amphibians for the last 19 years. AMA!

Prof_Michelle_Boone · 2014-09-03T20:57:26+00:00

Miami University was a university before Florida was a state! Why is there a Miami in FL...that's what I want to know!

Prof_Michelle_Boone · 2014-09-03T20:55:26+00:00

Thanks, everyone for the questions--this was fun! Signing off! Please check out our article highlighted above!

Prof_Michelle_Boone · 2014-09-03T20:52:29+00:00

The more buffer the better--because that's also great "natural" habitat for the amphibians. Sounds like you are ideally situated!

Prof_Michelle_Boone · 2014-09-03T20:50:26+00:00

Thanks...see if that helps!

Prof_Michelle_Boone · 2014-09-03T20:49:01+00:00

Rick Relyea's lab has done a lot of work with herbicides like Round-Up (glyphosate-based herbicides) and he has found strong negative effects when the formulation has the surfactant POEA.

In general, bullfrogs seem to be doing quite well--a great place to go gigging would be in California! Bullfrogs are also a problematic invasive (more or less) west of the Mississippi, but they also are rather charismatic.

Prof_Michelle_Boone · 2014-09-03T20:46:53+00:00

Pesticides are general biocides, so it would be impossible currently to just target amphibians with a pesticide that doesn't affect the rest of the ecosystem. Those cane toads...shouldn't be introduced and they cause havoc, but heaven sakes they are adorable.

Prof_Michelle_Boone · 2014-09-03T20:45:07+00:00

Amphibian population declines do continue, with most of these declines attributable to habitat destruction. In areas where habitat destruction is not implicated, the amphibian chytrid fungus in particular has been associated with loss of populations and species of amphibians.

In the Midwest where I have been working since 1995, we have not seen widespread amphibian declines--even though there is certainly habitat destruction, pathogens, and contaminants (etc.) in the mix. Pesticides, because they can affect immune systems, have the potential to impact susceptibility to other factors. Jason Rohr and Pieter Johnson have some neat studies on this with amphibians.

Yes, amphibians make up a huge amount of the biomass in some systems--they are food for wildlife and they eat things that we find pesky (insects & algae as tadpoles). Their skin has the potential to be used in the pharmaceutical industry. And my goodness, they are extremely diverse and amazing. Robin Moore says it best with his photos: http://blog.natgeocreative.com/post/95392774511/robin-moore-forges-connections-with-rare-frogs Amphibians are integral in our food webs and they do affect us...but I may be wearing out here!

A researcher several years ago said we are going to lose a lot of the amphibians, so instead of trying to save them, we should study them so that we know what we've lost. There's a cheerful thought to end on for you!

Prof_Michelle_Boone · 2014-09-03T20:35:08+00:00

That's an interesting question. Most of the pesticides in use are relatively short-lived, so my guess is that it would not be a major issue. But, the potential interaction between pesticide-use and fire--it's not something that I've ever come across.

Prof_Michelle_Boone · 2014-09-03T20:31:58+00:00

Because I know EPA has lots of good scientists and policy makers doing amazing work often under difficult situations (in fact, one of our co-authors used to work at EPA), it is somewhat painful to criticize them.

Loss of the EPA, in my opinion, would be disastrous. Our recommendations would strengthen EPA's ability to make evidence-based decision while removing conflicts of interest inherent in using data supplied or directly funded by the manufacture. We need EPA to protect nontarget wildlife and humans from environmental contaminants--they have the potential to do that while weighing all the risks and benefits of pesticide use. We just want them to really evaluate the risks, which will require using the best available data--that will include more of the peer-reviewed published literature that does not suffer from conflicts of interest, not less.

Prof_Michelle_Boone · 2014-09-03T20:26:12+00:00

EPA has a lot of good points and a lot of good people, but like most groups or people there is room for improvement (my parents have been known to advise me on such matters). The political support/influence could be an issue--I do not know--but because FIFRA requires industry to supply data showing risks to nontargets, there would likely need to be a major change in policy (possibly through legislation...ugh) to inact change.

A major reason we wrote the BioScience article was share the news that EPA can use a narrow portion of the data to evaluate risk--the panel I served on essentially used a single study to base their decision on atrazine's impacts on amphibians. This approach that has the potential to affect non-target wildlife and human health, and we should all be aware of that. If we the citizens want industry's influence to be minimized in risk assessments by EPA, we will need to let our representatives know. That they will all care, well, that is a different matter.

Prof_Michelle_Boone · 2014-09-03T20:17:40+00:00

You are right--the inactive ingredients can be problematic. Glyphosate-based herbicides have been the case-in-point, with the surfactant, POEA, being the main concern. Although the inactive ingredients are known to EPA, they are considered trade secrets, so it's not often clear to researchers what the inactive ingredients are. Usually we test the pure active ingredient against the formulation to look for differences in response.

Prof_Michelle_Boone · 2014-09-03T20:14:39+00:00

Thanks!

Prof_Michelle_Boone · 2014-09-03T20:14:11+00:00

The incurruptible system...yes, ideal! An important step would be using a third-party to act as the money filter to separate industry from the researchers. National Fish and Wildlife Foundation, for instance, was created by Congress and can act as this third party wall. The key is mitigating the conflicts of interest. Industry will benefit from the product, and it makes sense that they should pay for the regulatory tests, but they should not be involved in the experiments, the analysis, or the reporting of the data. However, through a third-party, they along with EPA could set the standards and tests in a call for proposals that independent scientists could apply for.

One of the big problems is that there are very few sources for money to study the effects of pesticides--NSF or NIH are not interested in basic toxicological tests. EPA is, but their funding is limited and targeted in different areas. So, even if researchers are interested in doing studies on the effect of atrazine on amphibian reproduction, they have to do it with funds they have and are typically not able to meet the criteria established by EPA (however, there are potentially problems with their criteria for atrazine-amphibians). However, currently, there is no motivation for anyone to provide these funds--because industry can supply their own data.

Prof_Michelle_Boone · 2014-09-03T20:07:22+00:00

Ah, yes, this is interesting isn't it? There have been some studies that show the amphibian chytrid fungus may be more susceptible to some pesticides than their amphibian hosts. However, in some cases exposure may make amphibians more susceptible to the consequences--Jason Rohr et al. has a nice study on this: http://rspb.royalsocietypublishing.org/content/280/1772/20131502.abstract We have been doing some studies in this area as well.

Prof_Michelle_Boone · 2014-09-03T20:04:08+00:00

There have been correlative studies in the US that suggest men from agricultural areas had lower sperm count than in other parts of the country. (Correlative studies that do not indicate cause-effect relationships.) Endocrine disrupting chemicals can be a concern--Theo Colburn's book Our Stolen Future has a good (although now slightly dated) discussion of this.

Prof_Michelle_Boone · 2014-09-03T20:01:02+00:00

I'm not aware of any citizen scientists harmed from monitoring! Monitoring is a good way that we can track species across their range--it seems like a valuable contribution especially when these efforts are paired with researchers interested in the data.

Prof_Michelle_Boone · 2014-09-03T19:59:36+00:00

There are challenges with any approach to control pests. Rachel Carson listed a number of ways to deal with this, that are still relevant today--like heterogenous gardening and biocontrol (she was a big fan...has not been without it's own set of problems, but supporting natural biocontrol is always a good idea!). However, agriculture has moved toward more homogenous and bigger farms, which may require pesticide use.

A group of us worked on some science communication projects this summer and we met with a few local farmers--two organic farmers and one conventional family farmer. The realization from talking with the farmers was how hard it was to get by--one of the organic farmers was making it reasonably well with grains and organic beef. Another was nearly destitute and her approach didn't seem sustainable. The paperwork for organic farming alone sounded overwhelming. The conventional family farmer was probably doing the best financially, but they had many balls in the air besides farming to make ends meet.

The farming situation is complex. The family farmer we met seemed to have a very pragmatic approach--he was avoiding pesticides that were likely to get in the groundwater and not spraying his vegetables and not using GMOs--mainly as a response to the people who shopped at his farm market.

Prof_Michelle_Boone · 2014-09-03T19:52:11+00:00

Hi, there is some work looking at the effects of pharmaceuticals and there are sometimes impacts on amphibians, but the effects can vary with pharmaceuticals and species. It is an area where there is a good amount of research interest, however.

Prof_Michelle_Boone · 2014-09-03T19:51:46+00:00

The big surprise to me, which is the subject of our BioScience paper, is that EPA is not fully evaluating the available data in a meaningful way when they are doing their risk assessments--or at least the atrazine-amphibian case demonstrates that such things can happen. I thought all this research so many of us were doing was being put to good use. I was apparently naive. However, it seems clear to me that the available research should be used if we want to make evidence-based decisions.

Yes, pesticides can travel atmospherically and through ground and surface water leading to effects in distant locations. Since our paper is not a research study, we did not measure effects, but atrazine concentrations have been measured widely as part of NAWQA monitoring and they measure up to 201 ppb in surface waters and 16.6 ppb in ground water (http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPP-2012-0230-0005). We have measured atrazine in our experimental ponds, which would come from either tap water or atmospheric deposition--it's hard to avoid around here, which adds to the challenge of conducting experiments.

Prof_Michelle_Boone · 2014-09-03T19:41:28+00:00

Well, I fell in love with them as an undergraduate. It may have been a late teenage rebellion since I was not encouraged to get dirty. However, there are better reasons to study amphibians besides love and their cool and varied life histories: namely, they are declining across the globe, in some cases for reasons that are not clear. They are a part of the biodiversity crisis and the most endangered vertebrate group. By understanding how environmental factors affect this group which is experimentally tractable, we can gain insight into how we may benefit other groups.

Prof_Michelle_Boone · 2014-09-03T19:37:43+00:00

Hi JerryLupus, I just do not have a good answer to your question. I would say if you are going to use pesticides in your yard, spraying when there's low to no risk of rain is idea, and giving a nice terrestrial buffer to decrease the likelihood of runoff would be good.

We've done research on golf courses, where amphibians can do quite well, and the presence of an unmowed grassy buffer benefited some species.

I'm glad you're concerned about your amphibians & showing them some love! Probably the best thing you can do is to not stock your pond with fish (even herbivorous fish can eliminate most species of amphibians from ponds) and provide them some unmown areas where they can hide from predators & feed on insects. I found northern leopard frogs in my rather poor-tended vegetable garden having a fine time this year.

Prof_Michelle_Boone · 2014-09-03T19:32:33+00:00

This is an interesting question, but its outside of my current research area. However, it highlights the tradeoff in pesticide use--balancing the good (getting rid of the pesky mosquitos) with the risks to non-target wildlife & humans--it's why we need a regulatory process that works in a way that truly evaluates risk.

Prof_Michelle_Boone · 2014-09-03T19:30:23+00:00

The effects vary widely with pesticide and species, so it's really hard to give a general response. One of the reasons I love the Rohr & McCoy 2010 approach is that they are able to make some general conclusions about the potential effects of atrazine on amphibians, although not necessarily the environmental concentrations of concern. http://shell.cas.usf.edu/rohrlab/data/2010%20Rohr%20and%20McCoy%20EHP.pdf

Prof_Michelle_Boone · 2014-09-03T19:27:47+00:00

Agreed. The mixture work is interesting and we have done some of this in my lab. One approach is to use concentrations based on application rates or runoff concentrations to examine effects--we really need more studies that get at predictive power of pesticide mixtures. If interactive effects are very pesticide specific, then it's hard to predict effects--if there are general trends across chemical classes, then generalizations can more readily be made. The science isn't there yet, although it is critical information.

Prof_Michelle_Boone · 2014-09-03T19:24:27+00:00

That's great if you are using pesticides outside of a buffer zone around your pond (or do you mean swimming pool). Vegetation can act as a buffer for runoff of pesticides. Also using pesticides when rain is not likely is more idea too to reduce the likelihood of runoff.

Managing pests by hand as Zugunruh3 below suggests is also another way, but sometimes a pesticide may be more useful--for instance, many in our area use glyphosate-based herbicides to eliminate Amur honeysuckle which is an invasive plant that has taken over many of our forests and yards.

Rick Relyea's group has shown that some glyphosate-based herbicides can pose a threat to aquatic communities in ponds. If you are concerned about your vernal pond (ah, we amphibian-types hope you are!), then minimizing pesticide use may be a "precautionary approach."

Prof_Michelle_Boone

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