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PRI's Environmental News Magazine

Minnesota's Mutant Frogs

Air Date: Week of October 11, 1996

Mutant frogs abound throughout the state of Minnesota. Steve Curwood speaks with Dr. Judy Helgin of the Minnesota Pollution Control Agency about the distressing deformities first discovered last year, and the State's new research plans to discover the causes.


CURWOOD: It's Living on Earth. I'm Steve Curwood. In the summer of 1995 a class of Minnesota teenagers on a field trip to a farm made a startling discovery. Frogs in the marshy areas were grossly deformed. Some were missing legs. Some had shriveled body parts. And others had extra limbs. Researchers soon discovered misshapen frogs in wetlands throughout Minnesota, and scattered reports of such deformities are coming in from as far off as Vermont and eastern Canada. The Minnesota legislature quickly voted an emergency grant to study the problem, and recently 60 scientists gathered in Duluth to chart a research plant. Dr. Judy Helgin of the Minnesota Pollution Control Agency joins me from the studios of Minnesota Public Radio in St. Paul. Dr. Helgin is overseeing the state's efforts to figure out what's going on. Dr. Helgin, you've seen some of these frogs, haven't you?

HELGIN: Yeah, lots of them.

CURWOOD: And so, what do they look like?

HELGIN: Well they don't look good. They're not only abnormal, that is with abnormal legs, missing legs, some with a missing eye, a few with extra legs. There are some possible abnormalities, internally, too.

CURWOOD: This must be very upsetting to see these frogs.

HELGIN: It is very upsetting and it's just really difficult. I know last year, when we were collecting at the end of September, I was measuring a frog, I was looking down at a frog that I was about to measure that was missing both of the rear legs. And it was just pulling itself along with the front legs. How that frog had made it for those 2 months or whatever is beyond me.

CURWOOD: What do you think could be going on here? What are the major theories or hypotheses here?

HELGIN: Well, at the conference that we had in Duluth recently, we prioritized two areas, one of which is the large area of chemical contamination or environmental contamination, and the other is the possibility that a parasite could cause the abnormalities.

CURWOOD: And which way do you lean?

HELGIN: Well, I lean towards the broader area of chemical contamination, partly because I don't think we've really demonstrated that the parasites can directly cause abnormalities in frogs.

CURWOOD: Are you looking at the prospect of synergy among more than one chemical?

HELGIN: That was discussed at the meeting, that we need to be looking, particularly in the laboratory work, at complex mixtures of chemicals or, for instance, at the interaction of ultraviolet light with particular chemicals, whether there could be a photo-reactivation.

CURWOOD: Because of the loss of the ozone layer.

HELGIN: Yeah. Yeah. And that the ultraviolet actually can damage the genes directly, but the thinking was that it's probably not that intense for the frogs here. But that possibly it could photo-reactivate a chemical that's in the water and make that the agent.

CURWOOD: Do you think this could be related to pesticide spraying or other toxic chemicals in Minnesota? I mean, you have a lot of agriculture. You grow a lot of corn.

HELGIN: Right.

CURWOOD: And other crops.

HELGIN: Yeah, that, I mean that's certainly one big area that we want to look at. We've been having conversations with our Department of Agriculture and with other people and in fact anyone who is aware of any changes in products that would be helpful for us to know about it. What complicates it is that there are 2 or 3 locations where there are deformed or abnormal frogs, where there isn't any agriculture immediately in the landscape. So just because it's predominantly an agricultural state doesn't necessarily mean that it is agricultural chemicals. So we have to keep our eyes open for other, you know, other kinds of chemicals like heavy metals, arsenic, mercury, selenium and cadmium are known to cause abnormalities in animals.

CURWOOD: There's been a lot of research recently about the relationship between tiny amounts of certain kinds of synthetic chemicals and heavy metals, persistent toxics, and hormone disrupters --

HELGIN: Right --

CURWOOD: -- that could lead to deformities and bizarre behavior in wildlife and humans. Do you think this, what you're seeing with the frogs, could be related to these chemicals?

HELGIN: Well in a broad way it could be. We -- the developmental process in the frog is driven and regulated by hormones or hormone-like chemicals, so it's certainly possible that a mimic, or a chemical that looks a lot like it, could muck up that process.

CURWOOD: Hm. What are the implications for human health?

HELGIN: Well that we don't know, and it's a real tough question to, you know, when we get that from a citizen it's really tough to respond to it. My personal feeling is that when we have something this serious happening to a population of animals, so widespread in our state, that we all ought to be concerned, you know, at both levels. You know, is there any possible consequence for humans? And then what are we, what are we doing to the environment and can we stop it?

CURWOOD: So, how are you going to look at what's going on with these frogs?

HELGIN: In a limited number of sites we're looking at the chemistry of the water and the sediments. We're looking for contaminants in the frogs themselves. And we're looking at their genetic material to see if there is gross damage to the genes in the frogs.

CURWOOD: Dr. Helgin, I'm wondering, how much money do you have to complete your studies?

HELGIN: Well this, this study from the legislature, this is the Legislative Commission on Minnesota Resources. They had some funding which we accessed in the end of May this year through next June, and it's $123,000.

CURWOOD: Excuse me. You're telling that you've got $100,000 to figure out what's happened to these frogs?

HELGIN: Well I think, what I have to say to be honest, is that what we're doing this year is just a start to identify the scope, maybe get some hits on some sort of analyses. It's going to require a collaborative effort of a number of different labs and state agencies, Federal agencies, and academic people. I think we need all the best scientific minds we can get on this.

CURWOOD: Thank you for taking this time with us. Dr. Judy Helgin is with the Minnesota Pollution Control Agency. Thank you.

HELGIN: Thank you.



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