FIFRA SCIENTIFIC ADVISORY PANEL ( SAP)

OPEN MEETING JUNE 19, 2003 DAY 3 OF 3 Located at: Crown Plaza Hotel 1489 Jefferson Davis Highway Arlington, VA 22202 Reported by: Frances M. Freeman 2 1 C O N T E N T S 2 3 Proceedings........................... Page 3 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 3 DR. ROBERTS: Good morning. I want to take the opportunity now to briefly reintroduce the panel. And let me as we have done in days previously begin with Dr. LeBlanc and ask each member of the panel going around the table to state their name, their affiliation and their expertise.

Dr. LeBlanc.

DR. LEBLANC: Good morning. My name is Gerry LeBlanc.

And I'm a professor in the department of environmental and molecular toxicology at North Carolina State University. And my area of expertise is endocrine toxicology.

DR. KELLEY: I'm Darcy Kelley. I'm a professor of biological sciences on the faculty for the center for environmental research and conversation and a member of the Earth Institute at Columbia University.

And my area of expertise is sexual differentiation of the amphibian xenopus laevis.

DR. KLOAS: My name is Werner Kloas. I'm professor for endocrinology at University of Berlin.

I'm also heading the department of inland fisheries at the Leibniz Institute of Freshwater Ecology and Inland Fisheries. And my expertise is endocrine disruptors acting on sexual differentiation 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 4 and thyroid system in amphibians.

DR. GREEN: My name is Sherril Green. I'm an associate professor in the department of comparative medicine at Stanford University. My special interest and expertise is in the care and husbandry of laboratory amphibians, xenopus laevis and other species.

DR. COATS: My name is Joel Coats. I'm in the department of entomology, chair of the department, and professor of entomology and toxicology at.

DR. ISOM: State University.

My expertise is environmental toxicology, environmental chemistry of pesticides.

DR. DENVER: I'm Robert Denver. I'm from the department of molecular cellular developmental biology of the University of Michigan at Ann Arbor. And my expertise is developmental neuroendocrinology of amphibians.

DR. GIBBS: My name is James Gibbs. I'm an associate professor of conversation biology at the State University of New York's College of Environmental Science and Forestry. And my area of expertise is amphibian demography.

DR. RICHARDS: My name is Carl Richards. I'm a professor of 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 5 biology at the University of Minnesota Duluth, and I'm director of the Minnesota Sea Grant College Program. My expertise is aquatic ecologist and landscape ecology.

DR. DELORME: My name is Peter Delorme. I'm a senior environmental risk assessor with the Canadian Government, Pest Management Regulatory Agency. My area of expertise is aquatic ecology and risk assessment methods.

DR. SKELLY: My name is David Skelly. I'm an associate professor of ecology at Yale University. And my area of expertise is population and community ecology of amphibians.

DR. MATSUMURA: My name is Fumio Matsumura. I'm a professor of environmental toxicology. I also serve as the director of our Center for Environmental Health Sciences. My area of expertise are molecular toxicology. And I also study some neural effect of the pesticides.

DR. THRALL: I'm Mary Anna Thrall. I am a professor of veterinary pathology at Colorado State University. And my area of expertise is veterinary clinical pathology.

DR. ISOM: I'm Gary Isom, professor of toxicology at Purdue University. And my area of expertise is neurotoxicology.

DR. HEERINGA: I'm Steve Heeringa, senior research scientist 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 6 with the Institute for Social Research at the University of Michigan.

I'm a statistician. My specialization is in the design of research and in specialist research relating to human and animal populations.

DR. ROBERTS: And I'm Steve Roberts. I'm a professor at University of Florida with joint appointments in the College of veterinary medicine in the College of Medicine, and serve also there as director for the Center for Environmental and Human Toxicology.

My areas of expertise are toxicology and risk assessment.

Before we proceed with the public comments this morning, at the close of yesterday, there was a little bit of confusion about the status of some research reports that were  from research performed by Dr. Hayes while at Ecorisk.

Dr. Sielken has offered to perhaps clarify the situation on that.

I would like Dr. Sielken to do that at this point for the panel.

DR. SIELKEN: Thank you, Mr. Chairman, and good morning to the panel.

Just to be as clear as possible, I did print out a copy of the clarification statement that I would like to make. And this is a clarification of the materials that I submitted yesterday to the record and to you all. That's my Texan coming through, you all.

On the morning of Wednesday, yesterday, Dr. Hayes made 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 7 reference to his study number 99XLATZ2. At the beginning of the afternoon session, I submitted four items to the EPA or SAP related to my review of the statistics in Dr. Hayes' report for that study.

These four items were as follows: And they are numbered here.

I won't read the titles. But the first one was a document that was prepared for a meeting with EPA in June of 2002. And that document was briefly summarizing the comments that I had made in my presentation to Dr. Hayes on September 19th of 2000 at Berkeley.

There is no change in that. I'm just clarifying that that was the first thing that I gave you yesterday.

DR. HAYES: We didn't have a meeting in September

DR. SIELKEN: That is the date that was on the front page of the presentation that I gave. It was at the meeting in Berkeley,

whatever date it was.

DR. HAYES: It was January or February. It wasn't September.

DR. SIELKEN: I have been corrected. It was January. Boy.

This is what happens when you go to bed at quarter to 4 in the morning.

It was at the one and only meeting that I attended in Berkeley with Dr. Hayes.

The second item was the overheads that I presented at that 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 8 meeting, whenever it was. It expressed my professional concerns as a statistician about characteristics of the study, including what Dr.

Hayes described as " haphazardly selecting a sample to analyze for laryngeal size" instead of taking a random sample, the need to explicitly provide more of the numerical data and errors I found in a spot check of the numerical accuracy of the report.

These overheads also contain the results of what I believe to be more appropriate statistical analyses of the data on laryngeal cross sectional area. And the details of my findings are written out there for you.

Basically, what I found was that there was not a substantial reduction in laryngeal size due to atrazine. This was the same conclusion that Dr. Hayes had noted in the body of his report, but did not note in his summary.

The third thing that I handed out, which was probably pretty obscure to you, was the copies of the 24 transparencies that I prepared to show examples of some of the errors and inconsistencies I found in Dr. Hayes' Excel spreadsheets, worksheets, and which I had presented to Dr. Hayes at that meeting in Berkeley. Correct the date.

I just listed there some idea of what those errors and inconsistencies were. I had copied the transparencies that I used to 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 9 identify those things and had provided those to you yesterday.

Now, where the confusion really probably arises is with respect to Number 4. And the version of the final report signed by Nigel Noriega on June 23rd, ' 00, was the copy that I submitted to you.

The first three of the items that I briefly discussed above were reproduced from original copies that I had prepared and brought with me to this meeting.

I did not think that I needed to bring my copy of the final report that I reviewed. I didn't think I needed to bring those here since I assumed that there would be plenty of copies here and I didn't need to carry it in my luggage.

Therefore, I asked Ecorisk staff to provide a copy of the final report for me to submit. The Ecorisk staff provided the only final report that was signed. And I assumed that that was the same report that I had been looking at.

Unfortunately, the only version of the  and unfortunately, the only version that the final report that was on the CD that was provided to the SAP members.

In other words, Syngenta provided to you the only signed final report.

When I asked the Ecorisk staff to reproduce the final report for 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 10 me, then that's what they did. They reproduced that signed report.

And that's the same report that is on your CD.

That's the version of the report that was readily available yesterday since Dr. Hayes' statement therein, that there were no abnormal, undifferentiated or intersexual gonads were observed in any of the treatments or controls had been discussed over lunch.

So that was why that copy was just out and ready and ready to go.

During Dr. Hayes' presentation, he had shown a figure showing the distributions of laryngeal sizes in male frogs. I understood him to say that this figure referred to later studies, that is, later than this 99XLATZ2.

I remember that figure since I had referred to it extensively in my presentation at Berkeley.

Since I had given all the copies of the final report to the SAP staff, I left the SAP meeting during the last public commentor's comments to check that this figure was indeed in the copies of the final report I had submitted to SAP.

To my chagrin ( embarrassment), I realized that the copy of the final report I had submitted could not have been the copy that I had reviewed for that Berkeley meeting since the figure of interest was 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 11 not in it and I knew it was in the copy that I had seen.

I understand that after I left the meeting, Dr. Hayes stated that the copy of the final report I had submitted was not the final version.

It seems that the signed final report that I copied and gave to the panel yesterday was not the final version. In fact, there is no final version. And there is only one signed and dated version. And that's the one I gave you.

Furthermore, all other versions of the final report I could find said that they were final reports. All the cover pages are the same.

And none were dated except for that one signed copy that I gave you.

The only version of the final report that contained the figure of interest was an unsigned version of the final report with a handwritten note on the cover page stating that, " Cathy, here is a copy of the report that was sent to Ecorisk several months ago.

And it's signed Kathy and then the phone number.

Here the first Cathy is Cathy Benz, who is the Ecorisk quality assurance person. And the second Kathy with a K is Katherine Kim who is CEO of Sokoke, Incorporated, and also Dr. Hayes' wife.

This is the copy that one Kathy sent to the other Cathy.

I checked this version of the final report. And it did contain the figure as I recalled it. Furthermore, this version contained on Page 41 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 12 the erroneous correlation coefficient of minus 2.61 that I had remembered commenting on, since a minus 2 is impossible.

Therefore, I went to Kinkos last night, and skipped dinner, and had 26 copies of this version of the final report made from the CD that had been provided to EPA.

So there was a copy of that signed version in the miscellaneous materials that Syngenta had submitted to EPA.

Although this version contains the statement that there are no abnormal, undifferentiated or intersexual gonads were observed in any of the treatments animals and the figure as I recalled it and the erroneous correlation coefficient that I remembered, a closer examination of the figure, about 11 o'clock last night, revealed that the figure labels were slightly different.

The dots and the figure were still the same. But the axis label had changed. And there was a line in there for where the female mean was.

I said, well, this can't be the report that I reviewed either.

So of the reports that were available and that Syngenta had provided to EPA and they had provided only the final or what they thought to be the final to the panel members, it meant that there had to be another version somewhere. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 13 I recall that at the time that I did my review, Keith Solomon,

Dr. Solomon, had received an electronic copy of the version of the final report and of the Excel spreadsheet that Dr. Hayes had provided and that I had reviewed.

Therefore, this morning, instead of waking at my office in the middle of the night, I asked Dr. Solomon to print a copy of that version of the final report.

And I will be distributing copies of that to the SAP members as well as to Dr. Hayes as soon as they come off the printer downstairs.

This version of the report also contains the statement about no abnormal, undifferentiated or intersexual gonads were observed in any of the treatments or controls.

Let me make a personal apology for my unintentional mistake of submitting the only signed version of the final report  or the only version of the final report that was signed by the study director to SAP, since, apparently, from Dr. Hayes' statement, it is not the final report.

I do apologize for any confusion. I have made in that box 26 copies of the version that Kathy sent to Cathy. And as soon as they come off the printer downstairs, I will give you the version that I received prior to the Berkeley meeting and that I reviewed at the 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 14 Berkeley meeting.

Just for your own edification, there is a not a great deal of difference in these reports, but there are some differences. You are welcome to review them at your pleasure and make your own decisions.

DR. ROBERTS: Thank you, Dr. Sielken, and thank you for your efforts to clarify that.

Dr. Hayes, I see you raising your hand.

DR. HAYES: I'll be brief.

DR. ROBERTS: That's fine. Please approach the microphone.

Let me just explain that what the panel is trying to do is obtain copies of reports of your earlier work with Ecorisk. And we're trying to get what represents the best  a best representation of that research. And apparently, there are multiple versions going around.

And if you could assist us by identifying which version you consider to be the most accurate representation of the research, that would be very helpful.

DR. HAYES: Yes. In terms of the gonadal abnormalities, I've already addressed that. I started out showing how we discovered the abnormalities. It was during that experiment where we were trying to measure steroids in animals. And we were sexing the animals without 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 15 buens ( ph). And that's when it was discovered. And I reported that to Ecorisk, not to Syngenta, to Ecorisk in November of 2000.

And that's when we reanalyzed the data. So that is correct. I already addressed that.

The other thing I wanted to say, I think Bob Sielken has already said better than I can, you see the sort of level of confusion and the round and round they go about, there is never a final report because there is always we need to do this, you do that. And things never get signed.

That's exactly why I left the panel. We started reporting adverse effects as early as 1999. And because there was never a final report and things never got signed on and they would ask to change this and that and this version and that  I think you see exactly why I left the panel.

So I won't comment anymore. It was exactly what was just described to you.

DR. ROBERTS: Okay. But we will now have several versions of that report. And if to the extent to which  before we close public comment, if you could look at those and identify which one you think is the most accurate

DR. HAYES: I can identify the last final report. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 16 DR. ROBERTS: That would be very useful for us.

DR. HAYES: Also, let me say, by the way, the data that he, Dr.

Sielken is talking about that he analyzed was not sent by me. I don't know where he obtained it. I did send data to Dr. Solomon and Giesy, but that didn't come from me.

DR. ROBERTS: Dr. Thrall has a question.

DR. THRALL: Dr. Hayes, would it be possible for us to have a copy of what you presented to us yesterday? Because that's probably what you're considering to be your final at this stage of the game. I think that would help us as we deliberate.

DR. HAYES: Yes. I don't think I have enough recordable CDs,

but I can burn it on to a CD and make it available. Yes.

DR. ROBERTS: If a CD can be made available to Mr. Paul Lewis, our designated federal official, he can make copies of the CD  and entered into the public docket.

DR. HAYES: Okay. And I'll look at this more carefully, but it does look like the final version. And it does look like it also has the raw data and all the numbers. I'll look through more carefully,

including the numbers that Dr. Sielken just said weren't available to him.

DR. ROBERTS: Dr. Hayes and Dr. Sielken, both, we 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 17 appreciate your efforts to clarify this for the panel.

Let us proceed, then, with public comments. And as I have done at the opening of each of the public comment sessions that we have had, let me remind the public commentors and the panel that we are here focused on some specific issues related to potential developmental effects of atrazine on amphibians.

So we're focused on scientific issues because we are the Scientific Advisory Panel. We're not here to consider policy issues,

legal issues and so forth.

So we could confine comments and our discussion to the scientific issues, I think that will be best. Let me see. Our first commentor that we have signed up for this morning is Dr. Jennifer Sass on behalf of Natural Resource Defense Council.

And she will be followed by Dr. Diana Post, just as a heads up,

Dr. Post. She may not be here.

DR. SASS: Should I start? I was just going to introduce myself while this is

DR. ROBERTS: Good morning, welcome.

DR. SASS: Thank you. I'm Jennifer Sass. I'm a Ph. D. with the Public Health Program of the Natural Resources Defense Council. It is an environmental nonprofit group. We're an advocacy group for 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 18 public health here in the U. S.

And we have been following atrazine very closely. In fact, it is because of a consent decree with NRDC that EPA is reviewing atrazine.

I want to first thank you all for giving your time to this extremely important issue. I know that you are all extremely busy.

And I know that this is a tremendous amount of time, both in attending the meeting and in previewing prior to coming to the meeting. And I want you to know that we really appreciate your attention to this important matter.

I also want to thank the EPA for preparing the white paper. As you know, most of the studies, in fact, all of the Syngenta submitted studies were not published and, therefore, not available for peer review or public scrutiny. So we rely on the EPA scientists to review boxes and boxes of data that we would never even want to look at were it publicly available because of the time and the energy required.

So I do really appreciate the excellent review that the EPA has done in the white paper. Thank you.

I'm going to make my comments very brief. First of all, I want to point out that the charge questions to the EPA in the white paper I 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 19 thought were unusually, unprecedently vague and ambiguous.

And that's possibly because the charge questions were in an unprecedented interest of the White House  actually passed through the White House for review prior to getting put into the white paper.

And I don't think they reflect the white paper in terms of the scientific assessment.

So I would like to start out by redirecting a little bit. What I think that the key questions are that the EPA really needs to address in its legal obligations with the NRDC in reviewing atrazine  in fact,

the reason that this SAP is here today is because NRDC negotiated with EPA to send this data to a scientific advisory panel for review and since at the time the EPA was not going to look at the data.

And the key questions in that agreement were, does atrazine threaten wildlife amphibian populations. And does atrazine act as an endocrine disrupter.

Those questions are not in the charge questions anywhere. But those are the key questions that the EPA needs to answer to fulfill its legal obligations and to complete its assessments.

And those really are the questions that this scientific advisory panel can provide input and advice on because of the expertise that is here around this table. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 20 I also want to point out that those are the key questions that are data driven. In other words, those are the questions that are going to be answered by a review of the science of the data that is available and the full body of literature. And from the answers to those questions, the next question will be, can atrazine be used safely.

At that point, the question that follows, which is not a question for the SAP, is at what concentration or dose or under what conditions can atrazine be considered to be safe. That's presuming that it can be used safely. Presuming there is some answer to that middle question.

At what concentrations or dose can it be used safe. In other words, from a policy point of view, we talk about a baseline or a no effect level or NOEL or reference dose and for human consumption.

Those are policy driven questions. Those are not appropriate questions for a scientific advisory panel. And in that light, I don't think that the white paper should be criticizing or critiquing or undermining the published literature because it doesn't provide that kind of an answer.

Those aren't answers that can be derived directly from the kinds of studies that the published literature were designed to answer, to tackle all kinds of questions.

So I would like to focus on the data driven questions and point 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 21 out that it is not a fair critique to say that a study doesn't come up with a dose response, therefore, the study somehow is insufficient to include in the review.

The NRDC asks that the scientific advisory panel provide a fair and complete review of the available literature with greatest consideration given to those data from robust and well designed studies published in the peer reviewed and scientific literature.

We ask that the amphibian data be evaluated as to its consistency with the whole body of available data, including mammalian, aquatic and mechanistic studies.

We ask that the scientific advisory panel provide its expert scientific opinion as to the effect of atrazine on amphibian health and to make recommendations as to whether or not it can be used in a manner that will not harm amphibian populations.

We believe based on the published literature and reviews therein that there is compelling evidence that atrazine is a multi site,

multi species endocrine disrupter.

Despite variability between study designs, there are data for mutually consistent studies with sufficient statistical power published in the peer reviewed literature demonstrating that atrazine acts in mammals, amphibians and aquatic organisms through at least two 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 mechanisms of action to disrupt hormonal pathways critical to reproductive development and function.

These findings compel a determination that atrazine is an endocrine disrupter on wildlife and that its use should be banned or severely restricted. That's the position of the NRDC.

I've handed out my comments yesterday or the day before, how ever long we have been sitting here, on paper looking something like this. I handed out 25 copies. I hope you have them.

It provides more of a comprehensive literature review. In the back all references are there for everything that I'm talking about here. What I'm going to do is very quickly breeze through that. I'm not going to go into any detail on any study. They are not my studies.

I can't defend or answer to them in any detail.

I just want to put the question of amphibian risk in the larger context of the published literature on atrazine.

What I want to point out in this graph, which, again, you have in the hand out is that there are a number of studies in rats, and there are a number of different studies that show tumor formation. But there are strained specific responses or rather differences between how strains of rats respond to atrazine.

So for instance, in one single study, a full litter resorption was 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 23 seen at low doses in the F344 strain, but not in the Long Evans and the Sprague Dawley strain, for example. And that was seen at 50 milligrams per kilogram when treated through gestational day 6 to 10.

There has been tumors seen in some strains of rats and not in other strains of rats and at different doses.

And those tumors have been reproductive organ associated tumors such as mammary and different reproductive organs.

There has been a suppression of luteinizing hormone and prolactin seen in Long Evans rats, but Sprague Dawley rats did not respond the same way.

Wistar rats, both males and females, showed delayed puberty.

Females were less sensitive. They showed effects at 50 milligrams per kilogram when treated during the period of critical development of those organs, whereas males showed effects at 12.5. Much less.

I want to point out that I think that the published studies demonstrate taken together that atrazine acts as an endocrine disrupter in rats, but the different strains respond differently.

Strains differ in their response to different concentrations and also with different measured endpoints. This does not represent disagreement in the published literature, but, rather, demonstrates the complex action of atrazine like all endocrine disruptors on the 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 24 complex web of hormonal regulation. Don't think of these pathways as linear.

All results summarized below in this table are of statistical significance. I only picked what the authors themselves picked as their conclusions or results.

I think that in addition there are some multiple mechanisms that have been demonstrated. I don't think any of these have been demonstrated in many studies, but they have been demonstrated at least to be indicative or suggestive of wider implications in the luteinizing hormone and prolactin levels.

There has been some studies in whole animals. These have been done by EPA scientists. And in fact, it's some of these studies that the EPA is now using to set a no effect level for atrazine.

As well there has been some demonstration of aromatase activity. You have heard about that ad nauseam in this meeting.

I want to point out, though, that the Sanderson study that was referred to, the first publication actually had one of the Ecorisk people on that as authorship, John Giesy. And then later in the subsequent follow up publication, his name was removed  or he did not participate in the second follow up study.

But he seemed to be in agreement with those findings, at least 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 25 the first time around. And there have been follow up studies. So again, I don't think that that data is tight, but I think it is indicative.

Atrazine disrupts hormonal pathways in multiple species. In rats, there is evidence that prostatitis has resulted in the suckling rat pups when the mothers were treated with atrazine.

These are interesting studies because the atrazine does not seem to have come through the milk to the pup. It actually affected the mother, the dam, and then the pups were subsequently affected by alterations in the dam hormonal responses to atrazine. And this was by EPA scientists.

There has also been demonstration of reduced testosterone,

reduced sperm motility and the delayed puberty in males and females in the Wistar rats. Again, this was in the EPA study.

In pigs, there is one. Delayed estrus after oral feeding of atrazine laced feed.

And in alligators, you have already heard, there is some induced aromatase activity.

There is one paper I found in tiger salamanders that I thought was interesting because it showed that the salamanders were responding differently at different concentrations, that at lower concentrations development was delayed, but size and weight weren't 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 26 affected, whereas at the higher concentrations development progressed normally, but size and weight were reduced.

Again, I don't think that this represents disagreement. I think it accurately represents the complex reactions of biological systems to hormonal disruptors.

I think that the published literature is consistent in demonstrating that atrazine may disrupt hormonal pathways resulting in disruption of reproductive hormones and reproductive cycles.

While the Ecorisk people were digging up data last night, I was actually on the phone late last night with someone named Shana Swan ( ph) who has just published yesterday in EHP on line a new study that where she collected, her group collected semen and urine samples from fertile men, about 200 each from Minnesota and Missouri, and shown that the risk of poor semen quality was elevated with several different pesticides. But with atrazine it was elevated 12 fold. And those are very statistically significant.

The populations are relatively small, but then again, finding a needle in a haystack. If this is able to be seen in such a small population, I think it is worth a follow up. And so does she. This data will be followed up. But as of today, this is, I think, consistent with the body of literature that we're reviewing. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 27 In frogs, there has been demonstrations in multiple species both in the wild and under controlled laboratory conditions.

The xenopus laevis, of course, is what the lab is addressing in large part. Also, in rana pipiens, lab and field work. Also, in bufo marinus, in field work.

The interesting thing about the bufo marinus work, and again, it is not publicly available, so I have not been able to review that, any published studies in any way, but my understanding from discussions with the author is that there is a built in concentration gradient because of the frogs closer to the cane fields had more effects.

In other words, more females, skin coloration, than the frogs living farther away from the field. But obviously, I'm not the one to discuss that work.

I think that the ecological risks from atrazine are unacceptably high and that there is no relief in site as the EPA assessment now stands.

And I will quote from EPA environmental scientists, the risk quotients exceeded the levels of concern for chronic effects on mammals, birds, fish, aquatic invertebrates and non target plants.

The risks are possible at maximum and in some cases typical use rates. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 28 So the EPA ecological assessors are extremely aware that the atrazine at current use rates under current use patterns is posing an unacceptably high threat to wildlife populations. And some of these wild populations include endangered species.

There are concerns, again, I'm quoting from the EPA scientists,

for adverse toxicological effects on freshwater and estuarine plants and their communities as well as indirect adverse effects on aquatic invertebrates and fish populations at monitored atrazine levels in surface waters.

So based on real readings of real atrazine in the real world,

there is real cause for concern according to the EPA ecological scientists.

The ongoing use of atrazine jeopardizes endangered species and their critical habitats. The exposure of aquatic communities to atrazine levels at 10 to 20 part per billion, this is based on an EPA assessment, can result in community level and population level effects.

This is significantly below the EPA's current proposal in its current assessment, which is to allow a seasonal average or 90 day average up to 37.5 part per billion before any action is triggered.

Up until 37.5 part per billion, the registrant, Syngenta, will 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 29 voluntarily do more intensive monitoring.

So other than monitoring, there will be no change in the use or use rate or use patterns of atrazine unless the 37.5 part per billion trigger level is exceeded for a 90 day average.

The U. S. Fish and Wildlife submitted comments on this. They claim that EPA's assessment underestimates the ecological impacts of atrazine in part because it does not consider sublethal effects on reproductive ability.

So to end and to thank you for your time, I want to point out that there are some very serious and more scientific questions that the EPA needs to address. And those questions are, does atrazine threaten wild amphibian populations and does atrazine act as an endocrine disrupter in wildlife populations.

These are data driven questions. And if the answer is yes, then the onus falls on the EPA to answer the policy questions of what doses and under what conditions atrazine can or cannot be used safely.

Thank you for your time.

DR. ROBERTS: Thank you, Dr. Sass.

Let me ask the panel members if they have any questions for you. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 30 Dr. Matsumura.

DR. MATSUMURA: Regarding this new report on the human sperms, did those people really measure the level of the atrazine in sperms?

DR. SASS: In the fluid, is my understanding.

I spoke with the author last night and have read some of the various different reports of it. And my understanding is they measured in the fluid levels.

Atrazine was one of a small handful of chemicals that came to light as associated with this. Alachlor and diazonal metabolites were the others.

DR. MATSUMURA: Thank you.

DR. ROBERTS: Any others? If not, thank you very much, Dr.

Sass.

It sounds like lots of folks were busy last night working.

Dr. Post has requested time to speak. I don't know whether Dr.

Post is here this morning yet. If not, we can move to the next person and then come back to her.

I have Dr. Stephen Sheffield listed as requesting the opportunity for public comment. Is Dr. Sheffield here?

Come forth, please, and identify yourself. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 31 DR. SHEFFIELD: Thank you, Mr. Chair. My name is Steve Sheffield. And first of all, I greatly appreciate the opportunity to address the SAP today.

In my mind, this is a very important issue. I would echo the comments of the previous speaker in acknowledging the amount of time and your willingness to serve on this panel. It is a very important issue. And I greatly appreciate all the efforts you are going to put into this over the next couple of days and the efforts you already put into it.

I should also indicate that I am an affiliate professor in the department of environmental science and policy at George Mason University, and that I'm actually providing these comments to the SAP as a professional wildlife toxicologist and private citizen, and that these comments shouldn't be construed as an official position of the university.

I should probably spend just a second giving you information on my pertinent background and experience. I have a Ph. D. in environmental toxicology from Oklahoma State University. I was on the faculty of environmental toxicology at Clemson University for four years. And I have been at George Mason for four years.

I have experience with both laboratory and field experiments 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 32 examining exposure and possible effects of pesticides on amphibians,

including both frogs, rana species, hyla species and xenopus as well as salamanders, ambystoma species, and have coauthored a book chapter on multiple chemical stressors and amphibians that will be published by SETAC press this summer.

I have been following with great interest the atrazine amphibian issue as it has unfolded over the last several years. As a result, I was wanting to share with you my perspective on the subject. I will include some thoughts on atrazine in general, some comments on the studies highlighted in the white paper, some comments based on the peer reviewed literature and some recommendations and thoughts on the subject.

As a wildlife toxicologist, one of the things that catches my attention is the high volume pesticides. That's not to say that all of them are bad. I'm just saying that when I go about looking at things,

looking at exposure and effects of pesticides on wildlife species, it the high volume ones that generally catch my attention.

In the United States, from the estimate of the literature and other sources I found, are roughly 75 to 150 million pounds of active ingredient annually over 40 years on up to 100 million acres of atrazine is applied or has been applied. It is ubiquitous in the 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 33 environment. It's found in all environmental media, including surface water, ground water, soil, sediment, air, including fog, and biota and it's atmospherically transported.

I think that this is an incredible volume of atrazine use and it's very difficult to comprehend that sheer volume of amount of use and the amount in the environment that I kind of liken it to the idea of trying to comprehend how much 100 million dollars is. I know I certainly can't do that. I have a hard time comprehending that number. That's why I'm saying that this is a very hard number to comprehend because it is so high.

Therefore, as Dr. Hayes made mention yesterday, control sites that are free of atrazine contamination are most difficult to find.

Further, peak application coincides closely with peak amphibian reproductive seasons. I see this as a scenario for potential trouble for amphibians, not just from atrazine, but from the various chemical mixture in which they are exposed.

Dr. Hayes' presentation yesterday, he had several different slides showing atrazine levels found in the environment. I don't need to repeat that. The levels that he has looked at and that some others have looked at are environmentally relevant, which is important.

I like to tend to discount some of the ones that look at really 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 34 high unrealistic levels and look at the ones that are just  focus on the ones that are just environmentally relevant.

One of the things that I like to focus on a lot is exposure routes.

And as far as exposure routes, I see amphibians getting exposed through oral, dermal and inhalation routes for atrazine. I don't know if there is any data on maternal deposition into eggs or not. But I imagine that that is possible. It does happen for other compounds.

It also needs to be considered the persistence of atrazine in the environment. The estimates range very widely. But it's generally relatively persistent. In aquatic systems, it can vary quite a bit.

In some of the experimental microcosms and mesocosms it does not have a very long persistence. But in some natural farm ponds and natural lakes it can persist almost a year. That's significant.

In terrestrial systems, one citation I found recently, the Talbert and Fletchall paper, 1964, atrazine persisted for 17 months in the soil at a two pound active ingredient per acre application rate.

Now I'm going to move to a couple specific areas that I'm concerned with. One is bioaccumulation. At least one person so far in this panel  in this proceedings has mentioned bioaccumulation.

The study by Allran and Karasov of 2000 found levels of atrazine in tadpoles that were six times higher than the concentration 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 35 in the test water.

That may or may not be a significant finding, but it raises a flag with me. It could possibly result in more continuous exposure of the target organs.

And amphibians are the only vertebrate taxa that I'm aware of that also accumulate organophosphate insecticides.

Another finding that could have a bearing on amphibians, given the suggestion that atrazine effects may potentiate or even synergize organophosphate effects.

As far as possible fitness effects of atrazine on amphibians,

there is a couple different studies that have indicated possible fitness effects. And I'm very concerned about that as well.

The Allran and Karasov 2001 paper used exposure rates of 0 to 20 micrograms per letter. And frogs at the highest level stopped eating immediately upon introduction of atrazine and did not eat during the entire 14 day experiment, an anorexic like effect that could have implications for fitness in amphibians.

The Brown Sullivan and Spence 2003 paper, which was a study that looked at atrazine and nitrate in combination, this particular study found that at 40 micrograms per letter of atrazine and 37 milligrams per litter of nitrate using an additive model, the snout vent 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 36 length at metamorphosis significantly decreased. They saw reduced growth and delayed metamorphosis.

This possible selective disadvantage for these frogs could result in fitness effects.

And finally, the Diana, et al., 2000 paper that examined effects of atrazine on amphibian growth and survival in artificial aquatic communities, they looked at hyla versicolor, which are the gray tree frogs, and atrazine concentrations of 0, 20, 200 and 2000 micrograms per liter.

They found frogs from two high dose groups were five percent shorter and 10 percent lower body mass at metamorphosis than those of the control and low atrazine groups.

Decrease in amphibian length and weight at metamorphosis can indicate a reduction in fitness in wild populations of anurans exposed to atrazine at these levels, although, I do admit that these levels, the 200 to 2000 micrograms per liter are not common, usually, except during the peak times when the runoff accumulates.

Now, moving to the studies that have been performed and published by Hayes, et al., first, I have to say that I was greatly impressed with the presentation given by Dr. Hayes yesterday. He was very thorough in scope and covered the contentious areas to my 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 37 satisfaction.

Overall, I would characterize these studies as very carefully conducted and analyzed, statistical sound and believe that the conclusions reached were reasonable given the data.

Do I find fault with some of his methodology? Yes. But not enough to discount the findings of the study.

Regarding the methodology, there is a few things that I would do differently. As an example, I would use glass containers instead of plastic. That's what I have used in any previous studies.

I would also use an atrazine formulation instead of technical.

That's an personal choice of mine. Just as examples.

I don't understand the criticisms of their work because they suggested a mode of action for the effects seen or for failing to find an acceptable dose response curve.

Although they speculate on a mode of action of a particular fact, that's a normal part of a discussion section of any peer reviewed scientific publication.

The high incidence of males with gonadal abnormalities,

whether it be testicular oocytes, intersex or hermaphroditic, how ever you want to say it, is of great concern to me. Particularly, if it's shown that these individuals are not fertile or otherwise 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 38 reproductively impaired, which has not yet been looked at.

From what I heard from the group on Tuesday, the intersex individuals do not get that way by themselves. It apparently takes exposure to an endocrine disrupting compound during gonadal development to make this happen.

In regard to the registrant studies, there was a relatively large number of studies that were funded by the registrant over the past year or two. Just as a personal comment or a personal observation, it was apparent to me that the studies were highly reactionary in nature.

And reactionary not only to the results of Dr. Hayes, but also for inclusion in the atrazine IRED document.

Therefore, I see that they are put together and conducted rapidly. They contain many design and other flaws that limited their use and rendered them largely uninformative.

Further, only one of these studies is peer reviewed, the Carr, et al., paper. And I really hope that I get the ultra rapid turnaround this paper was afforded when I submit my next paper to Environmental Toxicology and Chemistry.

As far as field studies, Dr. Hayes beat me to the punch on this one, but I'm going to expand on his comments from yesterday.

The study by Reeder, et al., 1998 appears to have been 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 39 completely written off as a study with nonsignificant data. However,

a point that seems to be overlooked on their work is the fact that although they found significant correlation between PCB and PCDFs and sex ratio reversal, they state that there was an association approaching significance, the P value of 0.07 between the detection of atrazine and intersex individuals.

The failure of this study to find a significant correlation for this was pointed out in subsequent studies on this topic, including in the Carr, et al., 2003 paper. However, I have to point out that I'm very comfortable in assigning a significance level of P equal of 0.1 for field studies such as this due to the large inherent variability and my willingness to accept a slightly higher error in these cases.

In fact, this is a common statistical practice for field studies,

including the set of field studies conducted at the EPA Corvallis mesocosm facility over the past 10 years, of which I have peer reviewed many of them for journals.

Therefore, I would ask the panel to consider the use of P equal 0.1 significance level in field studies when appropriate.

I'm not saying it's always appropriate. I'm saying that it's very commonly used in field studies because the variability is so high that you are willing to accept a little bit more error to try to tease out what 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 40 is going on. That's what I'm saying.

As far as endocrine disrupting abilities of atrazine, I strongly agree with Dr. Matsumura's assertion the other day that we should be looking at the hypothalamic pituitary interrenal axis in amphibians, a system that is involved in the stress response, metamorphosis, feeding and mating.

This is where the endocrine disruption action is in mammals,

and I have a hard time figuring out why we are not looking at this in amphibians.

As we heard on Tuesday from the registrants, these hormonal systems are evolutionary highly conserved through the vertebrate taxa. So we can reasonably expect that the amphibian HPI axis system would closely resemble that of birds and mammals.

Therefore, in addition to the examination of the hypothesized mode of action involving aromatase, we should be looking at possible impacts on ACTH, gonadotropin releasing hormone, FSH, LH and prolactin as well.

The HPI axis has been looked at in amphibians by Gendron, et al., 1997, who examined the functional integrity of the HPI axis in mudpuppies exposed to organochlorines in the field. They found contaminant induced disruptions within the HPI axis in mudpuppies 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 41 collected at most of their contaminated study sites.

There has been one mention so far in proceedings about immunotoxicology. I'm very interested in that area. The Christin, et al, paper, 2003, that was published in the most recent issue of ET& C,

Environmental Toxicology and Chemistry, exposed juvenile rana pipiens for 21 days to a mixture of six pesticides, including atrazine,

and then challenged with a parasitic nematode.

They found that pesticide mixtures caused diminished phagocytosis and splenocyte numbers, thereby suggesting a compromised immune system in these frogs.

I have three other considerations that I want to mention. One is an interaction consideration. Both potentiation and synergy. I alluded to this study earlier, the Belden and Lydy study, 2000.

Exposure to nontoxic concentrations of atrazine cause potentiated toxicity of OPs, of organophosphate insecticides in amphibians.

In a previous study by Lydy in 1997 showed the toxicity of atrazine and organophosphates was synergistic to invertebrates. The ubiquity of atrazine in the environment makes me wonder how much additional damage of the OPs are causing amphibians due to an interaction such as this.

And another paper by Howe, et al., 1998, there was an atrazine 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 42 alachlor mixture that was more toxic than either of the two compounds separately.

As far as formulation, this is a personal bias of mine, but I would submit that there is no such thing as technical grade atrazine in the real word.

The real world, which is the crops and other plants in which atrazine is applied, receives various formulations of atrazine. I believe that it should be formulations of atrazine that we should be examining and not technical grade.

I'm fully aware of the arguments for using technical grade pesticides in experiments, but in my mind, that has little practical use if it's not the exact chemical in which the organisms are being exposed in the field.

And my other area of consideration is atrazine metabolites and degradates. These compounds such as hydroxyatrazine and de ethylatrazine and others should not be ignored in any amphibian studies. These compounds are also ubiquitous in the environment and may be exerting some effect.

So the way I see it, the major studies that need to be done, are intersex frogs fertile? To me, that's the Number 1 thing from the two days and part of a third day that I have seen so far. That's the 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 43 question I think needs to be addressed immediately. Are these intersexed frogs fertile.

If yes, is there a problem. If no, you have identified a big problem. And then where do we go from there.

Number 2, as I alluded to already, the HPI axis in amphibians is something that is in bad need of being examined.

Number 3, I strongly suggest including a salamander species in the testing that will be done.

A study of mine that will be published later this year found that salamanders are on the order of two to four times more sensitive to an organophosphate insecticide than three species of anuran frogs including xenopus.

In this study, I used the marbled salamander, ambystoma opacum, and found it to be an ideal test species for studying possible effects of contaminants. It is an autumn breeder with relatively large clutch sizes, larvae that are relatively easy to raise in the lab and eggs whose development can be started on demand.

Number 4, the use of xenopus as a primary test species. I would point out to the panel that there are inherent strengths and weaknesses to going this route.

The strengths are well known. But in addition to being a 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 44 non native species and only related to our native species at the order level, there is an important life history difference between xenopus and native anurans. The adult xenopus are 100 percent aquatic,

whereas native anurans can spend significant time on land. Thus,

differential exposures to atrazine can occur.

Native species leave the water and feed on terrestrial pray items, move through sprayed vegetation and can pick up both dermal and inhalation exposure that could be more significant or at least different than in water.

For example, a frog moving through a freshly sprayed field could be exposed to atrazine through oral, dermal and inhalation routes where the atrazine would not be diluted as it would be in water.

This is the major point. These two differences can make extrapolation between xenopus and native anurans less reliable.

Number 5 is the tolerance resistance question. I noticed with interest that this has been touched on already in these deliberations.

It is important to address this issue because this might be contributing what is apparently being seen in the field, the populations of frogs in heavy atrazine use areas are still there.

In areas where heavy atrazine use has gone on for 40 years,

such as some of the areas we have heard about already, that is more 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 45 than enough time to have had enough generations in which to evolve genetic resistance.

Other vertebrates have done it. Mainly, muroid rodents and gambusia, mosquito fish. But I submit that the tolerance resistance question is very important to this. Particularly, in looking at why all these frogs are still there after 40 years.

And Number 6, population level effects. Certainly, this could be argued to be the ultimate question to examine. However, I firmly believe it may take many years to possibly see an effect at this level.

If some males are losing reproductive function, other males may hop right in and be more than happy to increase their contribution to the gene pool. If fertility is negatively impacted in intersex individuals, intersex males die and are lost to the gene pool without contributing.

As the frequency of intersex individuals increases in the population, the effective population size should decrease as fewer individuals are contributing to the subsequent generations.

Also, as frogs die out of a particular area, other frogs may come in and colonize, recolonize the area, making it likely very difficult to detect a population crash.

So if this scenario could be maintained for a relatively long 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 46 period of time, a population level effect may take many, many years to be detected.

My final thoughts. I have a couple final thoughts here and I'll end. The static renewal verse continuous flow through tests. I have modified this  I've added this since the deliberations have started.

I strongly agree with Dr. Hayes and others on this. I believe for these tests it is imperative to mimic as closely as possible the natural conditions of the test organisms.

Native anurans and xenopus tend to be found in pools, ponds,

vernal pools and ephemeral standing water such as puddles and ditches, not flowing waters like streams and rivers. And if they are found in streams, which I have found some in streams, they are likely found mainly in the intermittent pools within streams and not in the moving water.

Also, cost is a major factor in this. As being a researcher at a university, static renewal is relatively inexpensive and continuous flow through is so expensive as to be prohibitive to most researchers.

I do agree that the flow through systems successfully deal with the water quality issue, but it's probably not worth the trade off.

Second, I'm not going to spend any time talking about this other than just mentioning it because it is getting away from things a bit. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 47 But it is proposing that the EPA consider some sort of action the auspices of the Clean Water Act such as the National Water Quality Criteria for Amphibians.

Something like this was proposed previously in the 1990s, but no water quality criteria exists for amphibians in the United States.

And it's automatically assumed that criteria for fish and human health are adequate to protect all aquatic species, when, in fact, this assumption has yet to be tested.

Finally, regarding the white paper and the charge to the panel.

I was impressed with all the work done by Dr. Tom Steeger and his colleagues for this white paper. And I commend Tom and his colleagues for their effort.

However, when I got to the eight questions at the back of the white paper, that was a different story. To say that I was sorely disappointed with them is an understatement.

In my opinion, they were poorly written and off base from where I think this SAP should be headed. I say this in part because they failed to address one of the most fundamental questions one could ask regarding atrazine and amphibians. Is it an endocrine disrupter in amphibians.

Why is there no question that states, does the panel think, given 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 48 the data available from the 17 studies, atrazine is causing some level of endocrine disruption in amphibian populations. And does this effect on the endocrine system have the potential to translate into population level effects.

That concludes my comments. Thank you very much. And I wish you the best of luck in the next two days in your deliberations.

DR. ROBERTS: Thank you, Dr. Sheffield.

Are there questions from the panel? Dr. Green, then Dr. Thrall.

DR. GREEN: I have two short questions. You refer to the paper by Belden and Lydy of 2000, exposure to nontoxic concentrations of atrazine cause potentiated toxicity of OPs in amphibians.

Do you recall just ballpark what these nontoxic concentrations of atrazine were?

DR. SHEFFIELD: I don't, but I believe I have  no, I don't have the paper with me. I don't know what the compounds were. But I know that the two OPs tested were chlorpyrifos and diazinon. Those effects were potentiated with the atrazine exposure.

DR. GREEN: The second question I have is could you clarify the difference between technical grade atrazine and other formulations of atrazine? 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 49 DR. SHEFFIELD: Yes, absolutely.

As I started into this field, it just made sense to me that if you are going to study something in the lab, why not study something that has application.

As a toxicologist, the tendency is to use something that is pure or as close to pure as you can get so that you can actually say this is causing the effect. You don't want these other things in there mixing up with it.

But in pesticides, the stuff that is used in the field are called formulations. So they take the technical grade and they make formulations out of that so that you get a various percentage of the active ingredient in the formulation.

For example, diazinon, a compound that I have used quite a bit.

50 percent, an emulsifiable concentrate of 50 percent is used. And the other 50 percent is inert ingredients. So they will put other compounds in there to dissolve the diazinon and other things needed to make that formulation go on that particular crop or whatever application is being used.

So the technical grade is the pure or as pure as it gets.

Sometimes technical grade is only 95 percent, sometimes it's 99 percent. It usually ranges in that area. Formulations are what is used 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 50 in the real world. And For atrazine, there is many different kinds of formulations.

I don't know exactly what the active ingredient percent is in these formulations. Offhand, I don't know what it is. But it is some percentage. So what there is, there's other compounds, inert compounds in with the atrazine.

And they may have an effect on their own. Some of the compounds in with diazinon that's mixed in as an emulsifiable concentrate are known teratogens and other things like that.

So you are moving away from getting a look at a pure compound, but you're looking at something that is environmentally realistic because that's what the amphibians are getting exposed to.

Does that help?

DR. ROBERTS: Dr. Thrall, then Dr. LeBlanc.

DR. THRALL: I was particularly interested in the immunosuppression aspect of atrazine that we haven't touched on very much here. And I was wondering if you  I'm not familiar with the Christin 2003 paper you alluded to. I wondered if you could give me a little bit more detail on that, the pathophysiology of the nematode and how the decreased spleen function interacted with that pathophysiology. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 51 DR. SHEFFIELD: That's a really good question. I have the paper with me. I don't remember all the details of it because it just came out. But I will tell you I noticed, because I have done studies like this before, what they did, they used the pesticides as a  they exposed the organism to the pesticides. And they used a parasite as a challenge to the immune system and tested it that way.

And they used a mixture which included atrazine. Like I said, I have the paper with me. I can provide you a copy of that paper if you want to look at it. I don't remember all the details offhand because,

like I said, it just came out.

DR. ROBERTS: Dr. LeBlanc and then Dr.  Dr. Green, do you want to follow up to that question?

DR. GREEN: I want to follow up.

I also have that paper, Dr. Thrall. I think relevant to this discussion about atrazine, it was used in the mixture to treat these rana pipiens or various rana species. And then these species were inoculated with lung worms.

The conclusion by the authors, and there were two papers, the first paper just stated that it appeared that in the presence of atrazine in particular, the virulence of the pathogen was enhanced, and that it accelerated their life cycle such that they matured and were present in 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 52 greater numbers in the atrazine treated frogs. And they speculated that it might have something to do with immune suppression.

The follow up paper by the second group came back, repeated the same experiments and did T lymphocyte function tests. They show lymphocyte suppression, and they propose  I don't believe they followed up with this, that there might be B cell suppression and immunosuppression of immunoglobulins that would protect against parasites.

But neither of those two papers had any data that documented that the frogs were compromised in growth or that they died earlier because of it.

So they didn't extend to make any speculation about what this might do to an amphibian, a wild population that was exposed to atrazine.

But I think we have both of those papers here if you would like to look at them.

DR. SHEFFIELD: Thank you, Dr. Green.

The one other comment I make on that is that I think another thing that would be useful instead of using the parasite, and it's something that I've done in the past, is use a pathogenic challenge.

That way your endpoint is mortality. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 53 So you get to see immediately what the effect is. So you don't have to drag it out and look if the parasite is going to kill the animal down the line or not.

DR. ROBERTS: Dr. LeBlanc and then Dr. DeLorme.

DR. LEBLANC: You noted that atrazine has a bioconcentration factor of six in, I think, frog tadpoles.

In looking at that number, my interpretation would be, well, at least one thing we don't have to worry about is atrazine's ability of propensity to bioaccumulate in these animals.

But it raises a flag in your mind. And I just wondered if you could expand on that a little bit. Is there something unique to amphibians and bioconcentration that we should be aware of? Or is six really a significant number?

DR. SHEFFIELD: I don't know. It just struck me as something that I thought was  I guess maybe it was because of the fact that I had the other paper in mind and I was thinking about the Lydy work that showed the potentiation and synergy of atrazine with the OPs.

The organophosphate insecticides are also very ubiquitous in the environment. That's getting away from the purview of this panel,

but for me, anyway, it has implications.

If there is potentiation and synergy effects from atrazine 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 54 exposure dealing with the OPs, that, in my mind, is significant.

That's what it was  I don't think the six is alarmingly high or anything. It indicates that they do accumulate it and because I know that they are the only taxa that accumulates OPs also.

So there is something unique about amphibians that the other vertebrate taxa don't have.

DR. LEBLANC: Atrazine is pretty water soluble, and six is pretty nonsignificant. So I think in that respect, at least, the amphibians are probably responding like everybody else and they are not accumulating the material.

DR. ROBERTS: Dr. Delorme, then Dr. Skelly.

DR. DELORME: With respect to your concerns about formulation, are you aware of  versus technical product, are you aware of any studies that show concentrations of the formulants that are mixed with atrazine in the end use products and their concentrations in water?

Because, obviously, atrazine isn't applied directly to water. It is applied on fields. There is going to be differential degradations and the ratios may change.

Are you aware of any data that would indicate what of the formulants get into aquatic systems? 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 55 DR. SHEFFIELD: Not offhand I'm not. I'm not sure exactly what they use to make the atrazine formulations either. Sometimes

I don't know with atrazine, but sometimes a lot of chemical companies are very sensitive as to what they put in there. And that's not public information. I don't know if that's the case with atrazine or not.

So I don't know what that is. And I don't know how it differentially divides. Once it is applied and it starts its fate in the environment, I don't know how it divides up or not. All I'm maintaining is that I have seen many studies that have shown, that have looked at technical grade pesticides and other studies that have looked at the same pesticide with formulations and found very different results.

So I'm saying as a real world type situation, I think the formulations are important to look at regardless of how they divide out. The chemical pool is still going to be there in the amphibian's habitat regardless of how they divide out. The pool is still going to be there of all the different chemicals that are in the formulations.

Whether some of those chemicals disappear faster than others  they probably do. They have different fates because they are different chemicals.

I don't know. I don't really know what else to say on that one. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 56 DR. ROBERTS: Dr. Skelly?

DR. SKELLY: Dr. Sheffield, several other people that have presented to the panel have given the impression that field studies should be of kind of secondary importance or they are messy or something. And you are one of the first people to say that field studies may be of primary importance.

And I wondered if you could comment further on that and specifically talk about the distinction between observational field studies and field experiments in this sort of work.

DR. SHEFFIELD: Well, what I would say to that is that I'm of the opinion that this is  this and many other pesticide questions are very complex. It is not going to be answered by any one set of studies necessarily.

You have to use an integrated lab and field approach to this thing. And you may have to do something in the lab, then go to the field and at the same time go back in the lab and do something further.

And then maybe you have to go back in the field again.

It is not anywhere near  there is no road map written for this.

It is kind of like what you find by trial and error, by experimentation in the lab you can use to translate to what you might want to look at in the field. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 57 Plus, you can do some things that Dr. Haye's group and others have done with just looking at  going out to field sites that are contaminated.

They didn't  they picked their sites based on atrazine sales and then went there and looked at various sites. You can do a little bit more as far as preselecting sites or actually setting up experiments, experimental ecosystems, for example.

There has been some work on that done. I would like to see some more on that with this particular question, setting up experimental ecosystems. At that point, you have a lot more control over your system and it is in the field.

I would say that the field studies are definitely harder to deal with. They are harder  there just is a lot more things that can go wrong. But they are very useful.

And I my emphasis on that may have been simply because of the fact that I have a slight bias towards  and a lot of enthusiasm,

towards field studies.

They are a group package. They have to go together. And just doing one at a time is not necessarily anything. I mean, they can overlap. There is no written rules for this.

Basically, it's adaptive management. You are going along. You 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 58 find something. You adapt. You figure out what to look at next. If that question could be best asked in the field, then that's where you go. And if not, then you do more lab work.

So it is, like I said  in some of these areas in wildlife toxicology, you are going down a road that has not been paved yet. It is adaptive management.

But the field studies are important. But like I said, there is a lot more inherent variability. You can possibly accept a little bit more error because of that inherent variability. They are harder to do,

so they haven't been done as much. But they are valuable.

DR. SKELLY: Thank you.

DR. ROBERTS: Thank you, Dr. Sheffield. We appreciate you coming in and sharing your comments and thoughts with us this morning.

DR. SHEFFIELD: Thank you very much. Good look to all of you in the next two days.

DR. ROBERTS: Next public commenter is Mr. James Tozi ( ph)

on behalf of  I'm not sure what the note says. But I'm sure he will tell us.

And he will be followed by Mr. John Hall.

MR. TOZI: Thank you, Mr. Chairman. Good morning. I'm Jim 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 59 Tozi with the National Business Services. And with a title like that,

given the chairman's remarks that you want scientific remarks, you may say there is somewhat of a divergence there, but I assure you there won't be.

One of our main roles is to ventilate to the public the scientific basis or bases for regulatory decisions.

And the question is how do we do that. We do that by the use of a web site called Cyberactivist. US. You might not have heard of that site, but if you go to your web master, it is probably by traffic gradings the highest, if not one of the most highly trafficked, web sites in the world on the very specialized area of regulatory policy.

And it is used throughout the world.

Now, questions given that, why am I here. I think this panel,

and it just happens to be that you drew this card, that subsequent to the passage of a very important act, the Data Quality Act, and we look throughout the entire government for proceedings, this proceeding is the first major proceeding that's going to be subject to the Data Quality Act when the agency goes to use it.

And I haven't been here all the day, so you might have heard some of this before.

Now, keeping with the chairman's charge, I'm not going to get 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 60 into law because I don't think the law is any different than which most scientists do anyway.

The basic two important portions of the law says the data used by the government and regulatory decisions first must be reproducible and second it must be transparent.

And many scientists when a law passes, big deal, we do that all the time. Well, some of the regulators thought it was a big deal. The scientists did not.

So I just want to say that those two standards, reproducible and transparency, are going to be judged on anything that comes out of this whole proceeding.

What does that mean? That means any third party such as I, on National Business Services, or anyone that testifies, including this committee, you can write and say anything you want. I can write and say anything I want. It need not be reproducible and it need not be transparent.

However, if the agency is going to use anything that I give in this proceeding, anything any other third party gave or whether they are going to use your report, it is going to have to meet those two standards.

If it does not, any third party can move to strike that 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 61 information from decisionmaking in the government.

Now, a point that I wanted to emphasize here in terms of what we're going to do to advise this committee, we are very interested in this proceeding because of the data quality aspects.

But I think you can't look at data quality unless you have data.

And so, we are going to put on this cyber activist web site Monday evening a request that petitioners have made from EPA on the data on this proceeding.

I haven't looked at all the data, so don't ask me about all the details, but I'm advised that  and now would I want to compete with you on what the data means. But I'm advised that there's petitioners that have asked EPA for the data and it comes out in these kind of categories.

There were seven data sets, I understand, but this will all be on the web site, five of which were given to people, some of which were encryptive, some of which was withheld.

We're not going to take a position on these matters on the site.

That complete data set will be put up on Cyberactivist. US, and it will be out for public comment.

And the form, you are familiar with forms, it is not a web site.

It is a form and it is live so any person in the world, anyone in this 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 62 panel, anyone in this room can look at that data set and make a comment on it in realtime, which we'll be expecting a lot of comments.

And I will tell you when we put it up, we're going to urge people to ask three questions when they look at this data set. First, on the data received, was it reproducible. Second, how does use of encrypted data fit into regulatory proceedings. And third, when the federal regulatory agencies withhold data, how does FICA ( ph)

committees and how do people handle this.

We think by putting it on Cyberactivist. US and the charge of this committee as well as the composition of this committee on the web site, we think we'll be able to ventilate way beyond this proceeding an importance how this type of information is used by influential bodies such as yours.

We urge you to look at that site and the comments we'll receive.

Some of them, we've received thousands of comments. Thank you very much.

DR. ROBERTS: Thank you. I think there is a question from Dr. Heeringa and then Dr. Green.

DR. HEERINGA: Mr. Tozi, as a scientist operating in a university environment, I believe in full and open disclosure on this 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 63 data, obviously, there are proprietary interests, so and I commend you on that.

Just a comment too that data alone aren't sufficient. You need documentation to accompany it. I presume that part of your posting of these data will be to post the relevant documents that describe the study designs and protocols used to collect the data too. Because as you open that up to analysts, it is going to be very, very critical. And I think particularly in the case of the data sets we're looking at here,

that those documentations of procedures and assessments be available simultaneously too.

MR. TOZI: Let me ask you one question on this. I think that's very good. What I would encourage when we post these that anyone that has something that they want, and it is very easy, you just press,

click on a button and you put an attachment and it goes right up, we will put some of that up. The initial things are going to be what was response to the FOIA.

But I agree with you. There are going to have to be additional postings to interpret that. I have looked at some of the data. It is not my technical expertise to say what is there, but I agree with you.

We would encourage anyone that is involved in this proceeding,

whether around this table or in the room, that have relevant 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 64 information, because I will tell you that a lot of other agencies way beyond EPA  which, by the way, EPA on third party data and the Data Quality Act is probably one of the leading agencies.

You can criticize some stuff they have done. And I know the agency from when they were born, they are doing a very good job. I agree with you. And to the extent I can get that kind of information and people want to put it on, we welcome them.

DR. HEERINGA: One more additional comment. Just a technical question for people who would access this. What data storage format will it be in. Will it be in Excel spreadsheets? SPSS Sass? Raw data?

MR. TOZI: I can tell you how you do it now. You register on the site. You type something in. You press a button. I think it comes all out on HTML. There is attachment. The question is how do you get that attachment on there.

Generally, the people that put the attachments on now either have it on their web site and they cut and paste it over or they send it to us and we'll scan it in.

We prefer you have it on your web site because of the amount of traffic.

DR. HEERINGA: Thank you. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 65 DR. ROBERTS: Dr. Green had a question.

DR. GREEN: Yesterday and today several presenters have alluded to encrypted data, which I'm not clear what data people are talking about that has been encrypted.

Is it available to the SAP or could you clarify that?

MR. TOZI: Thank you. One of the people told me I was supposed to say that. Having worked in OMB for years, some things I don't address, maybe because I don't want to.

They asked me this, yes. From the FOIA requests that I understand that people filed out of these seven  I just say I haven't gone through all the data, five data sets came back, four of which are data.

When I say encrypted, I understood, but others in the room would know more about this than I, the term encrypted means it was in some machine code that you couldn't interpret.

So when they put that up, I want to ask them  they will identify which one was encrypted. What it meant. But I got from the conversations that unless you had some transition or translation codes, you could not interpret the data. You needed some other kind of information to turn it into meaningful data.

DR. ROBERTS: Are there any other questions? 66 1 If not, thanks very much for coming in and your comments and 2 letting us know about that.

3 Mr. Hall has requested the opportunity to speak to the panel.

4 As a heads up, he will be followed by Mr. Botts.

5 MR. HALL: Good morning, Mr. Chairman, members of the 6 panel.

7 My name is John Hall. I'm with Hall and Associates. I'm here 8 today representing the Kentucky Corn Growers Association.

9 By way of background, I'm an environmental engineer and an 10 attorney. I suppose maybe from this panel's perspective that puts two 11 strikes against me since I'm not a scientist per se.

12 In general, I have spent the last 20 years of my career dealing 13 with water quality related issues under the Clean Water Quality act,

14 development of water quality standards and the like.

15 The information that has been presented over the last two days,

16 as you are aware, not only has an effect on the reregistration of 17 atrazine, but also affects what EPA is doing in terms of its water 18 quality standards development for atrazine.

19 I come from that perspective in terms of my review as to the 20 information presented. In the water quality standards issue area, they 21 generally look at impacts in terms of what I will call the big picture. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 67 They don't typically parse out mechanistically why an impact occurs, what the exact cause of the effect is, but they look at whether or not there is a significant effect on growth, reproduction or survival, the three main endpoints that are often the, if you will, the end result of most research to decide what the real world impacts are.

I have just a couple comments with regard to the information presented and some comments regarding an earlier presentation to this panel.

Dr. Hayes' presentation in my mind raised at least one issue. I guess others have thought it raised several. His analysis focused on abnormalities in gonadal reproduction.

And without looking at the environmental significance of that,

the question I had was that these abnormalities were classified as such because apparently they weren't seen in certain controls during the study. But that in possibly later studies that were conducted, did find some of these abnormalities in the controls.

And therefore, I guess there is at least a question in my mind as to if the later studies exhibited some of these abnormalities, should the results of the earlier studies that classified certain things as abnormalities kind of gone back and corrected those charts. If that, in fact, was the case. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 68 The other thing I would note is that in terms of at least statistically, by classifying abnormalities as something you don't see in controls, you automatically get a zero abnormality in your control group.

And then when you do your statistics and comparison to that,

very often you can get anything being mathematically significant in terms of a difference compared to a zero effect on the control.

I would note, though, that at least out of all the studies that I have heard about today and in the prior days, that the environmental significance of any of these effects that have been noted is not demonstrated.

I have not seen any information presented that these effects actually cause impacts on frog populations, which in the end is I think what we're really concerned about.

Let me just move on to a couple other points. In the NRDC presentation, they indicated that the charge to this panel was misplaced. I could not disagree more.

The charge to the panel is not misplaced. What we have is different agendas occurring on from different parties that I believe are a little misplaced.

NRDC's view is that endocrine disruption equals ban. In other 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 69 words, any level of impact you find regardless of its significance to the real world triggers a ban.

And that trigger on endocrine disruption shouldn't be ecological significance. It is simply statistical significance.

That is not the standard. That is applicable under any federal law I am aware of.

The Clean Water Act requires you to avoid significant adverse impacts on aquatic life. And the endpoints that EPA has used for three decades are growth, reproduction and survival.

In other words, does this have a real world effect in the real world. You may find an effect, a histopathological effect in the organism. But the question is does that cause any significant adverse effect later on such as populations are affected  unless you don't classify something as a substantial adverse effect and regulate it.

OPP, the pesticides office, uses a no unreasonable adverse environment effect endpoint. Again, it is a similar type of legal standard.

All these programs in summary look at population based impacts. They require documentation of those impacts and not merely speculation that the impacts occur.

And that, of course, is the charge to this panel. And I think 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 70 you will serve us all greatly by answering the question of, whatever impacts these studies have shown, whatever they are, is there any information that shows these impacts are demonstrated to impact these organisms at a population level?

If the answer is no, then you don't regulate the pollutant  the constituent more stringently at this time. You may research it some more if there are questions that you have, but you don't decide that you are going to cancel a registration over something that is not connected to a real impact.

I will tell you one thing that was said in the earlier presentation that is clearly misleading and incorrect.

NRD stated that EPA's report confirmed that there were real readings and real world concerns showing significant risks. It is simply not true.

What EPA does when they do these risk assessments, I call it triage, I guess is the best way to look at it, you go through doing a very gross level of review and decide, my god, if you can pass that test, you are clearly not an effect.

That's what they call a Tier 1 assessment. And they make multiple, multiple worse case assumptions. And if you can pass all those worst case assumptions, you are out the door. We leave you 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 71 alone.

If you can't pass the series of worst case assumptions, they go to a higher level review. They don't declare that they have determined something that is causing significant real world effects.

You move on forward.

One example, and NRDC relied on it in notifying the EPA, they intended to sue them under the Endangered Species Act on this issue.

EPA in the report took data from what they called estuarine areas. The entire Chesapeake Bay. They took data from areas that were even 30, 50 miles upstream in non tidal waters, clearly freshwater systems. And in their report, they classified that as estuarine data.

You would have thought that the Chesapeake Bay had 30 parts per billion of atrazine occurring in it. In fact, it does not.

Well, if you read the EPA report, and not very carefully, what you think is the Chesapeake Bay has these enormous high concentrations of atrazine.

When you look at the underlying database, you find the concentrations of atrazine in the Chesapeake Bay proper, around the order of 10ths and 100ths of a PPB unmeasurable levels.

So in other words, you have to look a little more carefully at 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 72 the data before you decide that what is in that EPA report has demonstrated there is real readings, real world concerns before you make claims that leather back turtles are adversely affected in Chesapeake Bay.

I guess I would like to end with I applaud what this panel is doing. I think you will do us all a great service by clarifying what the real effects are, what the information really does show and whether and how we should move on to do further evaluations.

I think it would be extremely helpful if this panel confirms what I believe is a correct assessment on EPA's part that no one has demonstrated a real world connection to population based impacts from these endocrine disrupter endpoints.

That is not to say no one ever will. That is just to say that it has certainly not been demonstrated to date.

Thank you very much. If there's any questions, I'll be happy to take them.

DR. ROBERTS: Thank you, Mr. Hall. Let me ask the panel if they have questions.

I don't see any. Thanks very much for coming in and sharing your comments and thoughts with us.

MR. HALL: You are welcome. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 73 DR. ROBERTS: Mr. Botts is up next. Welcome, Mr. Botts.

MR. BOTTS: Thank you, sir. My name is Dan Botts. I'm the Director of the Environmental and Pest Management Division of Florida Food and Vegetable Association.

And as such, we're a voluntary trade association that represents the producers of about 60 different commodities in the state of Florida, including sugar cane, sweet corn and sod, all of which use atrazine.

But the reason I'm here today is because I have been following this issue for at least 10 years, even before the special review was issued in 1994. And have looked forward to some resolution at some point down the road in determining if, in fact, atrazine is safe, but more importantly, that triazines as a class of compounds. Larger acreage use of triazines in the state of Florida is simazine use on citrus.

And because of that, your deliberations here today pave a pathway of how this whole class of compounds will be dealt with.

And not only this class of compounds, but others as we move into the new process of determining endocrine disruption impacts and how to regulate those impacts for the office of pesticides programs.

I look forward to your deliberations, and looking extremely 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 74 forward to your final report, having sat through many SAPs over the past since 1997 after FQPA passed on all kind of issues, everything from modeling for OP, cumulative exposure to OPs and dose response curves for other issues.

I'm extremely encouraged by the discourse that has already occurred among the panel members and between the panel members and the people presenting. It is a much more engaged panel than a lot of SAP panels have been in the past.

And I will keep this extremely brief for that respect. I know you are already a half a day behind schedule. It's going to be extremely time consuming to go through the questions that have been presented. I would first applaud the agency for taking a very controversial set of data and the information and compiling it and looking at it in a manner to put forward the review that they did in their white paper and framing the issue to go forward.

And I'll be honest with you. I didn't read the charge of the questions until the plane ride up here, so I don't have as great a familiarity with the intent or tone of the questions as some of the other previous speakers have.

But after listening to the comments and conversations, I am sure that any issue that might be floated out in the vagueness or the 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 75 generalities associated with those questions will come forward as this committee deliberates.

I would draw one thing to your attention, though. In the presentation yesterday afternoon, there was one slide that was put up by Dr. Hayes relative to several epidemiology studies relating to the human health effects and potential carcigenocity of atrazine.

This committee can be informed by the deliberations of the SAP panel which was held in June of 2000. I'm sure that report is up on their web site, and would be available for you.

Most of the studies that were referenced in his presentation yesterday were discussed at length in that document. Whether they are relevant or not to deliberations of this panel I would suggest are probably not the case.

Some of the mechanistic issues that might have come up in the previous part on determining the cancer risk associated with atrazine probably are.

There will also be an SAP panel later this summer to deal with epidemiological information relative to cancer, and those discussions would probably be more appropriate at that point.

With that, I encourage you to move forward since you don't have to listen to us in the public anymore and can deliberate among 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 76 yourselves. And I look forward to your discussions over the next day and a half.

DR. ROBERTS: Thank you, Mr. Botts. We appreciate you coming in and sharing your thoughts and comments. Let me ask the panel very quickly if they have any questions for you.

I don't see any. Again, thanks very much for your thoughts.

Dr. Post had requested the opportunity to speak. I asked if she was here earlier. Is she here now?

This concludes the list of people who have asked previously to speak. Let me ask now if there is anyone in the audience who has not had an opportunity as yet to address the panel and would like to do so.

This will be your last opportunity to make a public comment.

Because when the public comment session closes, the next item of business will be for the panel to begin their deliberations.

So final call to the audience. Is there anyone who has not yet had the opportunity to address the panel that would like to speak?

Seeing none, this closes, then, the public comment portion of the meeting. Let's take a break for about 15 minutes and reconvene,

and the panel will then begin their deliberation of the questions.

( Thereupon, a brief recess was taken.)

DR. ROBERTS: Before we begin deliberation of the questions 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 77 posed by the agency, our designated federal official, Mr. Paul Lewis,

has a few announcements about keeping the docket squared away,

some announcements about submission of documents.

MR. LEWIS: Thank you, Dr. Roberts. Just briefly, during the break we distributed to the panel two pieces of information. One is a CD that was provided by the EPA Office of Pesticides Programs of additional data for the panel to review, to consider. In addition,

additional data, additional clarification provided by Syngenta based on comments they made yesterday.

The material is available to the panel now. In addition, we will make it available in the public docket.

DR. KELLEY: Do you know where this came from?

MR. LEWIS: Let me give this back to the chair.

DR. ROBERTS: The question came from Dr. Kelley regarding a CD that we were distributed, and she wanted to know the source. And it is the one that says Hayes data sets.

DR. STEEGER: The data sets on that CD are all of the data that Dr. Hayes has provided to support his report to Syngenta, the report that was distributed earlier today.

It also contains data to support the standard operating procedures that he developed in his lab to determine feeding rates. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 78 There is an additional file on there that provides the password for the one password protected data set that is contained among the seven.

DR. ROBERTS: Thank you, Dr. Steeger.

We have a follow up question by Dr. Kelley.

DR. KELLEY: For clarification, so the feeding data which were alluded to yesterday, does this just include the methodology for gathering them and not the results? Or does this include the results of different feeding regimens?

DR. STEEGER: My understanding is they are the results of different feeding regimens to determine what would be the ideal feeding rate for xenopus in Dr. Hayes' lab.

DR. KELLEY: Thank you.

DR. ROBERTS: And just as a general comment, the panel very much appreciates the data and the reports that were submitted during the course of the meeting and the comments.

We will try and consider and utilize those in our deliberations as best we can. But time is very short for us to be able to consider those. So we'll do the best we can with it.

Yes, Dr. Steeger.

DR. STEEGER: I want to make one more comment about the 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 79 encryption of the data.

As Dr. Hayes indicated in his presentation, his treatments are color coded. One of the data sets is codes dot X L S. It's an Excel spreadsheet. It provides the way of associating the colors with the actual treatment levels.

DR. ROBERTS: Thank you, Dr. Steeger.

Dr. Bradbury, the panel has received a great deal of public comment over the last couple of days, a lot of information.

We appreciated the opportunity to hear from the investigators and asked them questions. We now turn to deliberation of the questions posed by the agency. And I wondered if you had some introductory remarks or comments you wanted to make to help us make sure we have the right focus as we begin to that.

DR. BRADBURY: Thank you, Mr. Chairman. I appreciate the opportunity.

What I would like to do is just spend a few minutes to recapping where we have been over the last few days and perhaps help set the stage for moving through the questions.

What I would like to do is sort of again get us back into the context of the science and the risk assessment issue that we're facing and to put this question in the context of the agency's ecological risk 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 80 assessment guidelines, the process whereby the science is evaluated to help inform the regulatory decisions that the agency needs to make.

We talked about this on Tuesday morning, that one of the important phases of an ecological risk assessment is the problem formulation stage. It provides the context, it provides the foundation for proceeding further in the actual risk assessment.

The risk assessment, of course, is designed to help inform the risk management decision, science for a purpose. The science for this purpose is to help inform decisions about the potential risk of atrazine to amphibians.

As we discussed on Tuesday morning, ecological risk assessments tend to be an iterative process. And some of the speakers over the last couple days noted the risk assessment that has already been completed in terms of the potential effects of atrazine on aquatic community structure and function.

As part of that it iterative process, questions came up from the public, from NRDC and from others. And in the context of interacting with our agency's risk managers, it formulates another question.

The question being whether or not atrazine can cause developmental effects on amphibians, and, if so, what could be the consequences if that effect occurs. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 81 As one moves in theory from problem formulation into the analysis phase, that's where one blends the exposure information with the effects information and takes that into risk characterization where, in fact, we attempt to provide an estimate of the magnitude and likelihood of potential adverse effects. If you will, try to establish the probabilities that certain events can happen at different atrazine exposure concentrations.

The goal of the risk assessment is to provide that exposure response profile and articulate what the ecological significance of that exposure response profile is. And then communicate that to the risk manager.

And as we have heard over the last few days, there is a number of issues that come into play in making a decision about the registration and reregistration of a pesticide. Science is only one aspect of the overall decision. There are many other factors that go into making a regulatory decision.

The challenge for the scientific community, not just the scientists in the office of pesticide programs and the office of research and development, but the scientific community that spans academia industry and public groups, is to ensure that the science that goes into making these decisions is clear and transparent and provides 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 82 the risk managers an objective understanding of what we know and what we don't know so that certainties in their decisionmaking is clear to all concerned.

So that's the context. We're inside the box. We're inside the box of science, but it is science for a purpose and it is science that has urgency. Decisions have to be made. Making no decision is, in fact,

a decision. And it is a decision that is made in the context of whatever scientific uncertainty or certainties we have at the time.

So with that in mind, let us just walk through again a little bit of context on the road map that we're working through. Let's take a look at problem formulation again. And that's really where we are right now.

The white paper is, in fact, a problem formulation. Problem formulation is where we integrate available information to try to establish some sense of risk assessment endpoints in the context of environmental management goals and start to articulate what those measures of effects could be to make estimates about those risk assessment endpoints.

Based on the integration of available information, we focus on the formation of risk hypotheses and try to develop a conceptual model that could be used, a working hypothesis, if you will, to relate 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 83 the information that we do have in terms of exposures and effects to then set up the analysis plan for actually undertaking the risk assessment.

It is very critical in a risk assessment that has a lot of attention and has a lot of implications to use this problem formulation step to its utmost, to have it be rigorous, to gain the input from the scientific peers, to ensure that we've thought this thing through the way it needs to be thought through.

At the end of the analysis phase, there are sort of three broad paths one could imagine going down. One possibility is that through the analysis of the available information and dialogue with the risk managers it could be concluded that there is no need to do a risk assessment, that there is sufficient certainty in the information, in the context of the certainty that is required to make a regulatory decision that there is no need to do a risk assessment. That's one possible outcome of problem formulation.

Another outcome, possible outcome of problem formulation would be that, in fact, there is sufficient information to formulate the working hypotheses in the conceptual model. The analysis plan lays out how to use the available information to proceed with the risk assessment. Acknowledgment of potential uncertainties are 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 84 recognized in the analyses plan, but the decision is that one could go ahead and actually start doing the risk assessment to move into the analysis phase and begin ultimately to characterize risk.

A third outcome of problem formulation could be that there is sufficient information to formulate a reasonable conceptual model to formulate reasonable risk hypotheses, to formulate a reasonable working hypothesis and to develop an analysis plan that outlines the amount of information that is available and outline the data gaps that are facing the ability to proceed with the risk assessment with varying levels of certainty.

That's sort of where we're at right now in taking a look at the white paper, the problem formulation and gaining your insight and input and wisdom on the paths, the possible paths to go forward after problem formulation.

Is there sufficient information to proceed with the risk assessment and quantify to varying degrees the probability of adverse effects to amphibians in terms of development based on varying atrazine exposures?

Is there sufficient information to say there is no need to go forward; there is no plausible risk hypothesis for the potential of atrazine to cause adverse effects on amphibian development or are we 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 85 somewhere in between. That's the ultimate question before us. And a series of questions to help us get to where we need to get.

One thing I want to point out is that in the process of going through problem formulation and ultimately getting to risk characterization, we're talking about uncertainties, we're talking about what we know, we're talking about what we don't know and we're pulling that information together.

There has been some discussion that it is a weight of evidence approach. In fact, it is not a weight of evidence approach. In fact,

the agency's ecological risk assessment guidelines are very clear that it is not a weight of evidence approach.

In fact, it is termed the lines of evidence approach. And to quote from the agency guidelines, the phrase, lines of evidence, is used to deemphasize the balance of opposing factors based on assignment of quantitative values to reach a conclusion about a " weight." in favor of a more inclusive approach, which evaluates all available information even evidence that may be qualitative in nature.

So the point is we're not balancing pounds of information.

We're looking at lines of evidence. If I could be so bold as to change the analogy a bit from the risk assessment guidelines, you may want to think about it as pieces of evidence, pieces of information and 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 86 think about how we might try to build a puzzle. Think about building a jigsaw puzzle with lots of pieces on the table, all different shapes,

all different sizes, all different contours. Some with many edges,

some with a few edges.

Are all those pieces of information on the table even part of the same jigsaw puzzle? If they are, how many of those pieces on the table can one start to put together to start to build the picture? Is there enough pieces on the table that are starting to connect to each other to actually see what the picture is and to talk about the picture and describe the picture in great detail?

Or is it apparent that the pieces on the table don't even allow one to start to put the pieces together? Is it even possible that the pieces don't even belong in the same puzzle? Or are there enough pieces starting to come together that one can start to imagine what that puzzle could look like if one could get more pieces and can start to see what kind of pieces would be the most critical to start building the picture, to start painting the picture.

I think the other idea in terms of not using the term weight but using the term lines or pieces of evidence is that some pieces in this puzzle may be very, very small, but have lots of edges and they connect lots of pieces that are on the table. They may be very small, 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 87 but they may be very critical.

I think another aspect of thinking about this in terms of painting a picture or putting together a puzzle is that as we have certain pieces come together, there may be some gaps between some of the pieces. But depending upon the shape of the pieces and how those pieces are coming together, it may be very relatively easy to imagine what that missing piece would look like, i. e., we might be able to extrapolate to what that missing piece would look like, a reasonable level of confidence.

In some cases the edges of the pieces may lead us out into parts of the universe we haven't been before, and that may require actually getting some pieces to help put the picture together.

So it is an inclusive process. There is no right or wrong. There are no winners or losers in this process. The only winners are the people of the United States getting the kind of information it takes so that the risk management decisions can be informed.

The only winners in this operation, in this endeavor is a science, and the science being blended together to maximize all the information possible to make the most informed decision that we can make.

In going through problem formulation, one sort of gets the 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 88 impression it's a linear process. It is not. You sort of take different information and you work it through. Let's just recap real briefly sort of where we are coming from in the white paper.

We initially laid out on Tuesday morning the statement of the risk management goal, the environmental management goal as well as the risk assessment endpoints, and those being the reproductive and recruitment capability of native anurans. I don't think I need to go into great detail on that.

But what I would like to do is sit back and think about what that means in terms of being able to make some estimates about reproduction and recruitment of native anurans. That's a big question.

That's a question that brings in all sorts of fields of biology,

landscape ecology.

Problem formulation helps us get started on the process of putting this information together to answer that question.

When the agency has to take on chemical risk assessments in the ecological realm, we take on a challenge that, with all due respect to the human health risk assessors of the agency, I think we have a bigger challenge and a more exciting challenge, because we have to work across many layers of biological organization.

And the examples of the levels of biological organization on 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 89 that slide don't even capture all the levels of biological organization as Carl Richards and others on the panel know, but to at least get it all to fit on one slide, I think I can get the point across.

This concept on this slide has been published by many folks in many different venues. But I think it illustrates very nicely some of the challenges in the integration of information that is required as one goes forward in a risk assessment.

One could enter our examination of a question at any level of biological organization, but the concept is that in general as one goes down levels of biological organization, one creates greater understanding of the potential or actual interaction of a chemical with a biological system.

But certainly as one goes down in levels of biological organization, our understanding of the relevancy of those events at the population or community or landscape level become less and less certain.

So, in fact, doing an ecological risk assessment is a blending of many levels of biological organizations to inform, to help us understand what is going on and to help us understand the relevancy of the ecological risk assessment.

I think this panel is a nice example of the kinds of skills and 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 90 disciplines and professions that need to come together to understand in the problem formulation context of where we are and where we need to head.

So if I could try one more analogy. We talked about pieces of a puzzle in terms of creating that puzzle and creating the picture to understand where we are and what the world looks like. We also could think about it in terms of threads and how threads get woven together to create a tapestry, a tapestry that has texture, a tapestry that has a lot of vibrant aspects to it.

And it means we're blending in the skills and talents of folks that are experts in molecular biology and interactions of chemicals with receptors or enzymes as well as interacting with folks that are experts in landscape ecology and understanding how spatial and explicit descriptions of habitat are critical for understanding the population demographics of amphibians or other species.

So our challenge is how to weave these threads together to create a coherent picture that blends understanding and relevancy.

So that as a context, I would like just a couple more minutes if I can, Mr. Chairman, for Tom, Tom Steeger, and I to just touch base again on the integration of available information for this specific risk assessment, problem formulation for atrazine, touch on the conceptual 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 91 model again just to touch base and kind of get us all reequilibrated and then to just touch base on the first aspect of our analysis blend for the problem formulation.

DR. STEEGER: Over the past two days, panel members have received range of input from researchers engaged in studying the effects of atrazine on amphibian development.

Panel members have been provided copies of each of the studies discussed and EPA's assessment of the studies.

To a large extent, the presentations have focused on the results generated from research efforts. As has been pointed out by a member of the SAP, it isn't sufficient, though, to look exclusively at the data.

But rather, you have to also consider the study design and study conditions in which the data were collected.

As Steve Bradbury, Joe Tietge and I have pointed out, the agency follows a process for conducting ecological risk assessment.

The initial stage of ecological risk assessment is problem formulation where risk assessors work with risk managers to integrate available information on a chemical to define potential hazards, their impact on assessment endpoints and the uncertainties associated with the measurement endpoints used to identify potential hazards.

Typically, the agency relies on guideline studies to assess 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 92 risks. However, open literature and nonguideline studies are also considered.

Consistent with the agency's process for evaluating studies,

studies were evaluated using the following criteria: Experimental design, study protocols, protocols and quality assurance, the strength of the cause effect relationship, whether there was a dose response,

whether the observed effects have plausible mechanism of action that is consistent with what is known about the chemical, and, finally,

whether the measured effects are ecologically relevant.

Did we know what to expect? No. While the agency routinely receives studies that have a very standardized protocol and established databases on which to gauge the conduct and outcome of the studies, the studies under current review on amphibian effects represented a new area of information.

Did the agency have expectations on whether the data were realistic. As Dr. Giesy testified, the data are what they are. Agency reviewers, though, examine how the data were collected and analyzed to determine whether they would have come to the same conclusions as the study authors.

The agency, however, is looking for input from this panel on whether the data provided from the current suite of studies are 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 93 reasonable for gauging the effects of atrazine on amphibian development.

Also, there was some discussion about the agency's unrealistic expectation of a monotonic dose response curve. The agency is not focussed on the shape of the curve as much as on the consistency of the dose response.

We do not insist that a chemical exhibit a monotonic dose response, but simply that we are able to understand and project what type of response might be expected in a consistent fashion from exposure to particular levels of atrazine.

By now, the panel is painfully aware that the agency has reviewed seventeen studies that were received as a February 28th consent decree deadline. 12 of the studies were submitted by the registrant. Five were drawn from open literature. Seven studies were conducted in the laboratory and ten were conducted in the field.

While the presentations by researchers over the past two days have focused on study results, the agency has a number of evaluation criteria that extend beyond the data and examine the conditions under which the data were collected.

As I indicated, the data evaluation records for the 17 studies focused primarily on methodological inconsistencies that were 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 94 considered to have potentially critical impacts on the study.

While Dr. Sielken was correct in pointing out that collapsing replicates can potentially increase the likelihood of a type one error,

that is, drawing a conclusion that there is a statistical difference when one does not actually exist, agency reviewers conducted statistical analyses based on both the original study design and on collapsing the data sets in order to explore whether statistical relevancy could be extracted from the highly variable data sets.

However, it is important to keep in mind that regardless of what approach was used to view the data, confounding effects across all of the studies limited, if not precluded, the utility of the data regardless of how they were analyzed.

Thus, atrazine contamination in the controls, poor water quality, poor growth and development and survival, high variability in endpoint measurements, lack of reproduceability and unresponsive positive controls were recurrent themes that were considered critical.

One question that was posed on Tuesday was whether panel members should use any of these studies in determining whether there are sufficient data to gauge whether atrazine is impacting gonadal development.

However, we look to the panel's collective expertise on 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 95 amphibians' endocrinology, plus extensive laboratory and field research coupled with the understanding of the science of risk assessment to provide feedback to the agency on that very question.

The agency views that the studies do have utility in helping to identify potential effects on amphibian development. Additionally,

the studies provide insight on the sources of variability and they provide insight on the appropriate test species and study conditions that may be utilized in future studies.

If the risk managers wish to reduce the current uncertainties regarding the potential effects of atrazine on amphibians, the agency recommends that additional studies be initiated. These studies should build on the current body of information.

I suspect that it is often times frustrating for the public to recognize that the agency is not omniscient in its understanding of the available research on a particular subject.

While certain background information would be particular relevant to the measurement endpoints under consideration, the agency may simply not be aware of its existence.

Additionally, because of research limitations, the agency has come to rely on the testing of surrogate species to be representative of the effects of a very broad range of organisms. Thus, while it might 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 96 be ideal to test actual species that may be likely to be exposed to pesticides, these data are not typically available.

Additionally, surrogate test species are not selected based on their sensitivities to chemicals, but rather on their ability to survive under laboratory conditions.

Also, while laboratory test conditions may not be deemed as ecologically relevant, they are intended to provide sufficient control over environmental conditions to permit better elucidation of potential treatment effects.

Steve will now recap on the approach that the agency is going to recommend to address the current uncertainties.

DR. BRADBURY: Following up on what Tom just indicated, a written description of the risk hypothesis and, as the guidelines recommend to the extent possible, try to visualize what the risk hypothesis is in a conceptual model. And the white paper provided an image similar to this.

Before we get started on talking about this conceptual model,

I'm reminded of a quote, I think it is by George Fox that says, all models are wrong, but some are useful. And I'm really used to that phrase. My research is more on quantitative structure activity relationships. And we're always dealing with the fact that you're 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 97 trying to predict what you don't know.

So all models don't capture reality. But if used in the proper context, they provide insight into how to move forward.

I think another way to view it and perhaps a less harsh way would be to say that all models have limitations, but all can be useful if placed in the proper context.

I think a lot of what we heard over the last few days and we'll be discussing over the next day and a half will be the context of models, be they biological models, be they experimental models, be they representations of the field to try to capture what all of the ecosystems in the country do, they are models. And they are models used to try to help us find a path to move forward.

So in that spirit, a conceptual model is a working hypothesis,

but you have to start somewhere. You have to start somewhere.

So in our conceptual model, we're focusing on that top, for me,

the top left hand corner of our conceptual model. That's the focus and we're going to move forward. We have talked about the idea of linking the potential molecular effects to the effects in the working hypothesis in elevated E 2 ( ph) to the concentration on or the focus initially on gonadal effects in males which would then lead to the issue of impaired fertility, reproductive and success and then to our 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 98 risk assessment endpoint.

As we discussed in the white paper, the analysis plan of moving forward is a phased approach. Again, the idea that one doesn't have to know everything to know something to then moved forward in a risk management criteria.

This then lays out the first part of our analysis plan, which gets at taking a look at the apical effects of gonadal development in amphibians, provide the logical point to break through that logic train that's in the conceptual model. Again, to go back to the earlier slide,

understanding combined with ecological relevancy.

This working hypothesis starts off with sort of posing the question on ourselves, can we establish with greater confidence the potential of atrazine to cause developmental effects, start to get a handle on what the stressor response profile is for that effect as a launching pad to either simultaneously look for ecological relevancy as well as mechanistic.

That's what we'll be looking forward to hear, the panel's discussion on the pathway of moving forward.

The phase one aspect of the analysis plan we feel is the most important part or at least would hope that the panel would spend a fair amount of time on what we're proposing as phase one. Or if you feel 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 99 there is a different phase that we should start on, of course we'll be very happy to entertain that.

But at least from our perspective as a working hypothesis for you all to test, our phase one component then is focusing on whether or not atrazine exposure results in gonadal effects in males and perhaps females, and again, to try to determine what the dose response relationship is.

We have no preconceived notion of what a " right" dose response relationship is. That's not the issue. The issue is what is the dose response relationship and what kind of confidence do we have in quantifying that dose response relationship.

In the context of the phase one studies, we indicated on Tuesday morning a number of issues in terms of getting started. We started a little bit of discussion on Tuesday morning about the choice of the biological model to get started on. There probably will be a number of biological models we can consider.

Again, all models have limitations, but all can be useful if placed in the proper context, the context of understanding chemical toxicity, the context of studying ecological relevancy.

There is probably not one model that can answer all our questions. But what are the types of models we should use for the 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 100 different types of questions at hand.

We spent a lot of time as Tom summarized in looking at the available information in terms of some standards that exist in the scientific literature as a function of scientific bodies, in terms of some of the basic conditions that are required to do aquatic toxicology testing.

The history of aquatic toxicology is about 35 year old now.

Over 35 years there has been a lot of advancements in the technology of how to do aquatic toxicology testing. There has been a lot of work to describe what the conditions of organisms should be expected and the terms of doing those tests.

And in this context, the American Society for Testing Material has established standards, expectations of quality in terms of undertaking an aquatic toxicology test, including test with amphibians. We feel that's an important criteria to take into account in terms of doing aquatic toxicology.

This will be one of the exciting parts of the discussion, because the methodologies used in aquatic toxicology may not be the same methodologies that are used in developmental biology and they may not be the same methodologies that are used in field biology protocols. We're going to have to weave that tapestry, weave those 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 101 threads together to try to create a vibrant textured tapestry.

Obviously, you know where we're coming from in terms of how we think there is a way to approach maintaining appropriate quality in the bioassays and combined with keeping track at the end that's going to be required to test some of these hypotheses.

We obviously have a proposal on the table in terms of using a flow through technology to meet those ASTM standards. That doesn't mean that all tests that could be done to answer these questions have to be done with flow through. In our opinion, the most important criteria is going to be whatever method is used, it has to meet ASTM standards.

Whatever is needed then to answer the statistical power issues,

let it be what it will be, but ASTM standards we feel are important because they are based on 35 years of aquatic technology and we're somewhat nervous in backing away from what people have been developing over the years of aquatic toxicology, to not belabor the point, some of the data quality indicators that we discussed previously and which I'm highlighting just in the last few minutes.

So with that, we'll wrap it up. Again, just to bring it back home to the risk assessment issue at hand, is there sufficient information available to describe the certainties? What are the certainties? What 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 102 are the uncertainties?

Risk managers can use that information to decide if we should go ahead and do a quantitative risk assessment or if no risk assessment needs to be done. Under the assumption there may be a request for greater certainty in performing a risk assessment for atrazine, we laid out an analysis plan to describe what we considered would be important information to reduce the uncertainty.

We look forward to the dialogue with the panel.

DR. ROBERTS: Thank you, Dr. Bradbury. I think your presentation and your comments by Dr. Steeger are very important to help us refocus as we begin our deliberation of the questions posed by the agency.

A considerable amount of effort has been taken to put the available information regarding potential effects of atrazine on amphibians before the panel. It is now time for the panel to go to work and offer our best scientific evaluation and recommendations.

I would like to go ahead and take the first question and ask either Dr. Bradbury or Dr. Steeger if they would pose the first question to the panel.

DR. BRADBURY: I'll turn it over to Tom to read the questions.