MEETING
BEFORE THE
SCIENTIFIC REVIEW PANEL
OF THE
CALIFORNIA AIR RESOURCES BOARD
MARIAN MINER COOK ATHENAEUM
385 EAST EIGHTH STREET
CLAREMONT, CALIFORNIA
WEDNESDAY, NOVEMBER 17, 1999
9:44 a.m.
Kathleen Knowlton, CSR
License No. 11595
BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
MEMBERS PRESENT
Dr. John Froines, Chairman
Dr. Stanton Glantz
Dr. Craig Byus
Dr. Roger Atkinson
Dr. Anthony Fucaloro
Dr. Paul Blanc
Dr. Hanspeter Witschi
Others Present:
Jim Behrmann, ARB
Peter Mathews, ARB
Paul Helliker, DPR
Randall Segawa, DPR
Dr. Gary T. Patterson, DPR
Lynton Baker, ARB
Pamela C. Wales, DPR
Dr. Thomas Thongsinthusak, DPR
Dr. Andrew G. Salmon, CEPA
Dr.Martha Sandy, CEPA
Dr. Melanie Marty, CEPA
Dr. Andrew Rubin, DPR
Dr. James F. Collins, CEPA
BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
I N D E X
* * *
Page
Proceedings 1
Call to Order 1
Opening remarks by Chairman Froines 1
AGENDA ITEMS:
Item 1 - Presentation on Monitoring 4
for Multiple Chemicals
Item 2 - Discussion of Revisions of Draft 23
Document 11-15-99
Item 3 - Presentation of MITC 43
Item 4 - Discussion of Methyl Tertiary 83
Butyl Ether
Item 5 - Assessment of MTBE's Human 130
Health Effects
Item 6 - Discussion of REL 157
BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 PROCEEDINGS
2 * * *
3 CHAIRMAN FROINES: Shall we call the meeting
4 to order? We have a quorum. One person who will be
5 missing today, oh, is -- Peter Kennedy is unable to come
6 because of a health problem. But Gary Friedman, I assume,
7 is going to be here? Gary Friedman and Peter Kennedy will
8 not be here.
9 The first thing I'd like to do on the agenda
10 is introduce the panel to Paul Helliker who's the director
11 of -- the new director of the Department of Pesticide
12 Regulation. And so I ask Paul to say a few words. But we
13 welcome you, appreciate your coming to the meeting, and
14 look forward to be working with you.
15 MR. HELLIKER: Thank you. It's a pleasure
16 to be here. I assume this is the right spot to speak
17 from. I apologize for not having been able to participate
18 in the Scientific Review Panel meetings to date, but I'm
19 glad that I'm able to be here today, since I've been able
20 to review the draft findings that you've made, and look
21 forward to having a final document from you about the
22 workshops we've been having.
23 But let me just give you a little bit of
24 background. I have a -- an opportunity to meet with
25 Dr. Froines early on in my tenure and pointed out to him,
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1 I think we've been marking some good progress over the
2 past year, and I want to see that progress continue in
3 getting a good collaborative, working relationship going
4 with the Scientific Review Panel.
5 And I think that's going to set a good
6 foundation for how we go forward with responding to the
7 recommendations you have with what sort of prioritization
8 plans that we implement at the department for bringing
9 additional compounds to your attention.
10 So I think part of the background that has
11 generated some of the controversy might be when we
12 evaluate pesticides, we have the ability to move fairly
13 quickly, and we have in the past. So I think that might
14 have been some of the source of the discussion or the
15 difference in approach that we have with ARB.
16 But my goal is to make sure that we go
17 through the similar process to what the Air Resources
18 Board does, and make sure that all of our decisions about
19 toxic air contaminants are decisions that merit by the
20 input from this panel.
21 Because I look to you as being one of our
22 primary guiding organizations when it comes to our
23 scientific decisions. So I won't take much more time than
24 that. But look forward to the discussions today. And I
25 did want to point out I did sign yesterday the
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1 recommendation or the decision to list methyl parathion as
2 a toxic air contaminant. So thank you for your
3 recommendations on that. And I look forward to the
4 additional ones in the future.
5 CHAIRMAN FROINES: Thank you. Everyone has
6 a new record. That's great. Just great. And thank you,
7 Craig Byus, for the effort that went into methyl
8 parathion. I think that is, Paul, a good example of
9 interaction. Craig and Ruby Reed worked very closely and
10 worked very effectively. And I think that Craig is a real
11 advocate for Ruby. And so that -- that seems to me to be
12 a great model for how we can work effectively together.
13 So without further ado, we're going to --
14 we have -- the problem we have today is a problem we have
15 normally. It's with Stan. I'm not supposed to make
16 jokes, because he makes them back. But we'll cool it.
17 DR. GLANTZ: Let the record indicate that
18 Dr. Froines made me get up very early this morning to get
19 here. Actually, the problem is with Dr. Froines.
20 CHAIRMAN FROINES: Stan actually has to
21 leave early. And so we are going to try and move
22 relatively quickly, so we can at least get through item 3
23 before he leaves. He's finished item 4 from his
24 compound. So -- so we have some tension about working
25 through items 1 through 3.
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1 Any case, so the first item on the agenda is
2 the case study of multiple pesticides sampling. And I
3 don't know who's presenting. This is, in essence, a
4 continuation of a workshop on prioritization and exposure
5 monitoring. So this will complete that small workshop.
6 MR. SEGAWA: Good morning. I am Randy
7 Segawa. Yeah. We're trying to get the lights fixed
8 there. I'm Randy Segawa with Department of Pesticide
9 Regulation. And this is a -- pretty much a continuation
10 of a workshop we had a couple months ago that got cut
11 short. And I will be presenting some case studies or
12 hypothetical examples on how we could possibly monitor for
13 multiple chemicals.
14 First off, I'd like to point out that this
15 is a hypothetical exercise. Department of Pesticide
16 Regulation and the Air Resources Board have had a series
17 of meetings to discuss the different alternatives and
18 options for monitoring multiple chemicals, but we haven't
19 settled on a concrete plan yet. So right now we're just
20 still in the discussion stage.
21 For this particular exercise, I put a couple
22 limitations on -- on how we might accomplish this. One,
23 I -- for this exercise, I wanted to come up with some sort
24 of objective criteria for grouping and prioritizing the
25 different chemicals that we might be monitoring.
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BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 The other restriction I had placed on it, is
2 that I set up the examples so they fit within the current
3 resources available to DPR and the Air Resources Board.
4 And the other factor I consider -- or did not consider,
5 actually, is the risk assessment and mitigation. Those
6 factors did not play any role in determining the groupings
7 and priorities that I'll be discussing.
8 I'm going to present three separate examples
9 on how we might group for multiple chemicals. And the
10 first example I'll look at a crop-type grouping using
11 cotton as an example. In this second example, I've done a
12 chemical-family-type grouping using organophosphates as an
13 example.
14 And then finally I'll present a county or
15 month-type group where we've looked at the highest county
16 and highest month for the various counts of pesticides and
17 group them together. For this exercise I've included 157
18 pesticides, both candidate toxic air contaminants as well
19 as those chemicals currently on the toxic air contaminant
20 list.
21 I've used our current priority system,
22 DPR's report 9601, which was published back in '96. And
23 so is somewhat outdated, but we are working to revise
24 that. But for this exercise, I've used that for all the
25 candidate scores. And then for those chemicals that are
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BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 currently toxic air contaminants, I assigned an arbitrary
2 score of 15.
3 A lot of this exercise, the priorities have
4 to do with the pesticide-use data. And I've used the 1996
5 through 1998 data for these examples. So for each of the
6 157 chemicals that we want to try and monitor for, I've
7 selected four different factors. I've looked at the crop
8 of highest use for each of a hundred fifty-seven. We
9 determined the chemical family each of the hundred
10 fifty-seven belonged to.
11 From the pesticide-use data, we determined
12 the county of highest use for each of the hundred and
13 fifty-seven. And we've also determined the month of
14 highest use for each of the hundred and fifty-seven.
15 So our first example, the crop grouping --
16 what we've done is taken, for each of the 157 chemicals,
17 the highest crop for each of those chemicals. And cotton
18 actually came out on top where 23 of the chemicals had the
19 highest use on cotton. Structural pest control was second
20 with 14 chemicals at highest use for that particular site.
21 And then almonds was number three.
22 DR. GLANTZ: Structural pest control is like
23 termites and things like that?
24 MR. SEGAWA: Correct. Yes. And so if you
25 look at the list of chemicals there, there are 23 that are
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BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 used on cotton, used throughout, mainly, the Central
2 Valley. You see that Fresno and Kern County are probably
3 the highest for virtually all those chemicals, which you
4 expect, since those are the largest cotton-growing areas
5 in the state.
6 DR. BYUS: Are they -- pardon me. Are --
7 you're not saying that 23 are used on -- all 23 are used
8 on one cotton field, are you?
9 MR. SEGAWA: No.
10 DR. BYUS: You're just saying between all
11 the cotton?
12 MR. SEGAWA: Correct. Correct. Yes.
13 CHAIRMAN FROINES: One other question --
14 DR. BLANC: But your house did have 14
15 chemicals applied prior to your purchase.
16 CHAIRMAN FROINES: And xylene you have
17 listed as a pesticide. Is that considered a pesticide on
18 cotton?
19 MR. SEGAWA: It's both considered an active
20 ingredient as well as an inert ingredient in many
21 products.
22 DR. FUCALORO: Solvent?
23 MR. SEGAWA: Correct.
24 DR. BLANC: Why would it be considered an
25 active ingredient if it's a solvent? Because it has
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BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 health effects, but not because it has pesticidal --
2 MR. SEGAWA: It does have some pesticidal
3 effects for cotton. I'm not sure exactly what pest they
4 are trying to get with xylene.
5 DR. BLANC: But actually, I guess I should
6 ask the question more clearly. Because, do you know from
7 a regulatory point of view, is a toxic additive to a
8 pesticide which is not pesticidal considered inert? Does
9 the term "inert" designate a non-pesticidal component or
10 does it imply nontoxic component?
11 MR. SEGAWA: It implies non-pesticidal
12 component.
13 DR. BLANC: So theoretically an insert
14 ingredient can still be toxic to humans?
15 MR. SEGAWA: Correct.
16 CHAIRMAN FROINES: I was on a National
17 Academy of Science Committee that actually discussed this
18 issue. And you find there are a lot of compounds listed
19 as inert that are by no means inert. And that's a problem
20 at some level that hasn't received attention, although
21 there has been some focus on it at some points.
22 DR. BLANC: And a follow-up to that
23 question. Do you know whether inert -- other inert --
24 well, do you know whether there are other solvents which
25 are considered inert? It seems that xylene is not
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BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 considered inert. That would reason I ask specifically
2 about solvents, because of their volatility, clearly they
3 would be of interest to this panel as potentially toxic
4 air pollutants.
5 MR. SEGAWA: If I understand your question
6 correctly, yes, there are solvents which we may consider
7 toxic. But our list is as inert ingredients in pesticidal
8 products.
9 CHAIRMAN FROINES: He's asking a different
10 question.
11 DR. BLANC: I'm asking, how -- would we end
12 up ever hearing about them at this panel? For example,
13 suppose there was a hypothetical pesticide that was very
14 widely used, which had a significant inert percentage of
15 the solvent dioxane, theoretically. Would that be
16 something that would ever enter into our inventories? Or
17 we ever hear about or that would appear in the --
18 otherwise on our radar screen?
19 MR. SEGAWA: I'm not real sure. I know that
20 under some of our regulatory authority -- for instance,
21 our groundwater program, we do have the authority to look
22 at inert ingredients as potential groundwater
23 contaminants. I'm not sure we have the same authority for
24 toxic air contaminants.
25 DR. BLANC: Can somebody from the ARB
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BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 comment on that?
2 MR. BAKER: I didn't hear the question. I'm
3 sorry.
4 CHAIRMAN FROINES: Paul is asking the
5 question, there are compounds that are listed as active
6 ingredients and inactive ingredients. There are times
7 when the inactive ingredients are toxic. And if they're
8 volatile, that has potential significance for the
9 designation of those compounds as toxic air contaminants.
10 And the question is, would that ever come
11 before this panel? And he's, I think, not entirely sure.
12 I think that -- and so the reason ARB comes into it is
13 because, if there was an inert volatile compound that
14 might be considered a toxic air contaminant, then that
15 might come -- well, ARB, I think, 1807 lists pesticides,
16 and that would be the role of DPR.
17 So I think their authority would be -- with
18 respect to DPR would be with respect to pesticides. But
19 inert ingredients might be with ARB. I don't know.
20 That's the question.
21 MR. BAKER: This is Lyn Baker from the Air
22 Resources Board. I would assume that solvents are
23 carriers that might -- might fall under this category that
24 would be toxic, but would not be pesticidal -- would not
25 have pesticidal activity.
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BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 That the Air Resources Board might look at
2 compounds like that under our toxic air contaminant
3 process, but not as carriers for pesticides. If they were
4 solvents, we would probably be viewing them from
5 industrial sources, and might have regulated in that way
6 rather than as a -- as an inert, pesticidal ingredient.
7 Jeannette, would that --
8 MS. BROOKS: That's correct.
9 DR. BLANC: But let's say a pesticide came
10 before this panel in the process that we were embarking
11 on. And we're going to come back to this subject later.
12 But let's take our grouped --
13 Suppose that our suggestion to group the
14 cholinesterase inhibiting -- suppose our proposal to group
15 the cholinesterase-inhibiting organophosphate pesticides
16 goes forward and we receive risk assessment on 35
17 organophosphates. Are we going to be assured that as they
18 are marketed, none of those organophosphate pesticides
19 perforce also include volatile, toxic-air-contaminant
20 solvent carriers?
21 Because if something is marketed in a
22 particular way, which means that when it's used there will
23 be release of a toxic air contaminant solvent then we
24 should -- I would assume it would be our obligation to
25 designate that pesticide a toxic air contaminant, even if
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BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 it's not on the basis of its active pesticidal component.
2 But rather on the basis of its inert solvent carrier,
3 unless it's reformulated to exclude that solvent carrier.
4 MR. BAKER: That would certainly make sense,
5 Dr. Blanc. But the Air Resources Board doesn't have
6 regulatory authority over pesticides. So to -- we would
7 not have the authority to regulate or to --
8 DR. FUCALORO: Is there any group, I mean,
9 within the state that is looking -- is this slipping
10 through the cracks, I guess is what Dr. Blanc is referring
11 to. That if you have a series of solvents that are used
12 to deliver pesticides, is there anyone paying attention to
13 those solvents?
14 I'm given to understand that xylene shows up
15 on this list, because the pesticidal action rather than
16 its use as a carrier or solvent. So between the two --
17 the two organizations, there anyone looking at these? I
18 mean, that's a fair question, and maybe you can get back
19 to us.
20 MS. BROOKS: Well, in the case of xylene,
21 xylene is already listed. It's a hazardous air
22 pollutant. So it's already a toxic air contaminant. And
23 Melanie was reminding me, there are some other solvents
24 that would be the same.
25 And the only -- at the Air Resources Board,
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BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 we do have a consumer products program where this would be
2 the public being able to go in and buy off the shelf Raid
3 or something like that. And we're limiting the volatile
4 organic content of those. And a lot of the carriers are
5 what we're regulating, trying to get as low as we can,
6 close to zero BOC.
7 And we know, too, those products are
8 labeled. If these carriers are toxic like xylene, and
9 maybe toluene, they have to be labeled for Proposition 65.
10 So there is at least a warning. But I know what you're
11 saying as far as control measurement development.
12 DR. FUCALORO: Yeah. Clearly if a carrier
13 were benzene, it would raise red flags all over the place.
14 I understand that. But suppose, for example -- I'm just
15 following up what Dr. Blanc is saying.
16 Suppose there is a solvent that is really
17 not being considered in any way as no one's done any
18 investigation of it, and a manufacturer uses a carrier
19 that uses a solvent that no one has investigated, is there
20 any mechanism within the state to say, this is something
21 we ought to be looking at? I assume it's the ARB.
22 MS. BROOKS: Under our toxics program, in a
23 consumer product that's sold, we can do a toxic control
24 measure for a toxic air contaminant. And in fact, we have
25 a branch at the board that's looking at break cleaners and
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1 engine degreasers that contain perchloroethylene right
2 now. And they're planning to take a control measure to
3 the board next year.
4 So I think for a commercial product where
5 the Air Resources Board has authority, we could develop a
6 controller measure. And, in fact, we are. For a
7 pesticide that's used on application at a farm, I don't
8 think we could control the xylene content.
9 DR. GLANTZ: Could DPR?
10 MS. BROOKS: We have to double-check on
11 that.
12 MR. BAKER: I would think that would fall to
13 DPR.
14 CHAIRMAN FROINES: I'm going to cut this
15 off, because we are way off what this session is about.
16 DR. BLANC: Sorry. My fault.
17 CHAIRMAN FROINES: No, nobody should
18 apologize. It's a very important discussion, and we
19 should take it up at a later date. We've now certainly
20 raised it, and so let's leave it for the moment. I'll
21 just, as Chair's prerogative, will say this last word on
22 it.
23 DR. GLANTZ: This is part of Dr. Froines'
24 effort to always shorten discussions.
25 CHAIRMAN FROINES: Under AB 1807, compound
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1 is listed as a toxic air contaminant. The law then says
2 that a risk-management process will follow. It doesn't
3 say, "only for these uses, compared to these uses."
4 So if there is a toxic air contaminant, say
5 xylene, then it seems to me that the issue is what is the
6 appropriate, regulatory-management strategy that you would
7 follow for that compound, for any and all of its uses.
8 And so it would be up to ARB to determine those uses and
9 to determine strategies for control.
10 MS. BROOKS: That's correct.
11 CHAIRMAN FROINES: That's, I think, what the
12 question is. And this is obviously something that hasn't
13 come up before, so we can talk about it later. Thanks.
14 Thank you.
15 MR. SEGAWA: Okay. This figure here shows
16 the use for all the 23 chemicals that we were just
17 discussing. As you can see, that the San Joaquin Valley
18 has the highest use for chemicals used on cotton. And of
19 course, that is where most of the cotton is grown.
20 But you can also see that there is use of
21 these chemicals throughout much of the state down, in the
22 Imperial County and southeast desert region, as well as
23 even far up north in the Modoc County area as well.
24 And don't forget, while these chemicals may
25 have highest use on cotton, cotton would not be their only
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BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 use. They would also be used on other crops. Okay.
2 Moving on to --
3 CHAIRMAN FROINES: Not much of those, do you
4 think, of the 20 -- we know xylene's organophosphate. But
5 how many of the others do you think are organophosphates?
6 MR. SEGAWA: Organophosphates? Phorate is
7 an organophosphate. Chlorpyrifos, of course,
8 methamidophos, naled, def, and ethephon.
9 CHAIRMAN FROINES: I only ask that question
10 because, clearly, where you have a common mechamism of
11 action, you would want to look at the compounds with
12 common mechanism of actions collectively, if one were able
13 to.
14 MR. SEGAWA: And that's a good segue into
15 the next slide. Because the second example does deal with
16 the chemical-family-type of grouping. Again, for the 157
17 candidate and TAC chemicals that we're looking at in this
18 exercise, 20 of them are organophosphates. And they came
19 out highest in the priority score in the grouping.
20 Organochlorines came in second. There are
21 eight chemicals in that group. And carbamates is third
22 with nine chemicals. And so if you look at the list here,
23 these are all organophosphates used on variety of crops.
24 And you can see, used at a variety of locations and
25 throughout most of the year.
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1 DR. ATKINSON: So it looks as though at
2 least three of these are also organochlorines.
3 MR. SEGAWA: That's probably true, yes. And
4 then as a third example, we took the 157 chemicals and
5 determined the combination of county a month of highest
6 use. So that if we were to try and monitor for multiple
7 chemicals, it's, of course, ideal to be monitoring at the
8 same time in the same place for multiple chemicals.
9 And in this type of grouping, Fresno in July
10 came out as the highest -- scoring with seven chemicals in
11 that group. Fresno in June was second with five
12 chemicals. And Fresno in August was third with four
13 chemicals.
14 And the drawback to this type of grouping,
15 as you can see, is that the chemicals in the highest
16 group, the Fresno in July, are different groups of
17 chemicals. And so they would require several different
18 sampling and analytical methods to try to get them all at
19 the same time.
20 After looking through these various
21 exercises, we came to several conclusions regarding the
22 shortcomings and problems. Number one, it's difficult to
23 monitor the complete groups, whichever the three groupings
24 we chose. It requires monitoring in several different
25 seasons, as well as several different areas, and using
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1 several different types of monitoring methods.
2 While this is, maybe, a good approach for
3 the ambient monitoring, it probably does not work for the
4 application monitoring, since in most application
5 monitoring, one to three chemicals would be applied at the
6 same time, not groups of 20 or more.
7 And of course, risk-assessment factors have
8 not been addressed in this exercise. And it's very likely
9 that, to do the risk assessment for multiple chemicals,
10 particularly outside the chemical-family grouping, would
11 be very difficult. Any questions?
12 DR. FUCALORO: Yeah. I guess you were
13 looking at some sort of intersection of these lists; is
14 that correct?
15 MR. SEGAWA: Correct.
16 DR. FUCALORO: And looking at the monitoring
17 multiple chemicals, county look, the month group, it seems
18 to me that quite possible that you don't need an
19 intersection. I missed the original pesticide workshop,
20 so I'm a little unclear as to what's going on. But what
21 you consider, the list under Fresno in July, probably
22 Fresno in June and August, too, as being a candidate for
23 multiple testing.
24 MR. SEGAWA: Yes, you're correct, that if we
25 were actually to follow this type of scheme, that we would
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1 probably be monitoring in June, July, and August, yes.
2 And the list would expand as well, of course.
3 DR. FUCALORO: I'm not encouraging people to
4 go in Fresno in June, July, and August. In fact, I would
5 discourage them.
6 CHAIRMAN FROINES: I make just one comment.
7 That list of compounds, the seven chemicals -- 1, 2, 3, 4,
8 5, 6, 7 -- in terms of your '96 priorities, they -- we
9 have here the first compound the highest priority, the
10 fifth highest priority, the seventh highest priority, the
11 39th highest priority, and 42nd, 58th and 63rd.
12 So it represents, actually, a relatively
13 important cross section of compounds that your priority
14 document identified. And in fact, one would say, these
15 are all candidates that are worth taking a look at, given
16 their priority in the DPR '96 document. Has -- has Lyn --
17 have you and Lyn talked about the actual analytical and
18 sampling methodology required to look across --
19 MR. SEGAWA: We did ask Air Resources Board
20 to take a quick look at these various lists and come up
21 with a ballpark estimate as to how many methods are
22 required, and how they would go about doing it. In this
23 particular case for the seven chemicals in the
24 county-month grouping, they thought it would take two or
25 three methods.
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1 CHAIRMAN FROINES: Two or three?
2 MR. SEGAWA: Yeah.
3 DR. BLANC: That sounds technologically
4 feasible.
5 MR. SEGAWA: Uh-huh.
6 DR. BLANC: I think from some of this,
7 probably be tempered by logistical considerations also.
8 But one advantage I think you may have, given the weather
9 and pesticide-use patterns, is that even for certain other
10 areas outside of Fresno County that you might be
11 interested in, the time frame when you would need to
12 sample would be a different time of the year, thus making
13 it, you know, physically possible for the staff to
14 contemplate sampling.
15 For example, you know, there's a -- there
16 certainly is a heavy concentration of use in -- probably
17 in Imperial County at certain times of the year, and
18 similarly in Salinas Valley which may differ from Central
19 Valley.
20 MR. SEGAWA: I would agree, yes.
21 DR. BLANC: So therefore, there would be
22 things that you -- sampling there, even if they -- they --
23 so I guess, another thing I would suggest, in addition to
24 the very excellent analysis, would be an analysis where it
25 was divided up by agricultural region, and you saw what
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BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 was the time at which the most number of chemicals were
2 used in Imperial County. So that you leave aside the
3 issue of, how does Imperial County rate compared to
4 Fresno.
5 It's going to be clear that areas in the
6 Central Valley are going to be the heaviest pesticide
7 use. But there may be very real issues in some of these
8 other geographic agricultural areas, because the types of
9 pesticides used are likely quite different.
10 MR. SEGAWA: Yes. My guess that
11 meteorological conditions would be different in those
12 areas as well.
13 DR. BLANC: I would suggest that you do that
14 analysis as well. I would like to see that analysis for
15 three or four of what you would imagine would be key
16 areas. And I guess, those key areas would be the North
17 Central Valley as opposed to Fresno and Kern, Salinas
18 Valley, Imperial, and then perhaps, based on your map
19 here, probably certain other hot spots.
20 CHAIRMAN FROINES: Comments? Thank you very
21 much. This is a really nice piece of work. And I think
22 it just raises a lot of interesting questions. So
23 hopefully we can pursue it over time. I think it's really
24 well done and thought-provoking, as you can tell. Have
25 you ever done -- never mind. I'll ask another time.
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1 MR. SEGAWA: Okay. Thank you.
2 DR. GLANTZ: Can I just ask one quick
3 question? So where are you planning to go next with this
4 in terms of -- I mean, I agree with the others who said --
5 I think it's real interesting. I mean, are you going to
6 further develop these ideas and come back again to us or
7 work with ARB? What's the sort of next -- what's the plan
8 over the next couple three months?
9 MR. SEGAWA: We can do that. We of course
10 need additional discussions with Air Resources Board to
11 see which approach we do want to take. If it's possible,
12 can go with our current resources, and we can come back to
13 the panel with a more updated recommendation.
14 CHAIRMAN FROINES: I should tell you, by the
15 way, that I have a Ph.D. student who's doing a study of
16 multiple-pesticide exposures in Mexico. She's looking at
17 about ten pesticides, and she's doing the analytical
18 chemistry herself.
19 And she's also looking at soil, water.
20 She's doing a multi-media, multi-environment and looking
21 at -- also at urinary metabolites, and looking at what
22 families and children of workers and applicators are
23 getting. So we will keep you informed of what that data
24 looks like, because it's very parallel, in some respects.
25 DR. GLANTZ: Getting back to the earlier
25
BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 point, though. I hope that at some reasonable time they
2 can come back with a sort of next iteration on this.
3 CHAIRMAN FROINES: So we should define an
4 action item. What's a good action item of a report in
5 three months for this? What's a good reasonable time
6 frame for you?
7 MR. SEGAWA: We can do that in three months.
8 CHAIRMAN FROINES: That good? Thank you.
9 MR. SEGAWA: Thank you.
10 CHAIRMAN FROINES: The second item on the
11 agenda is the prioritization -- B and C we'll take
12 together, is a discussion of the prioritization and air
13 monitoring document that we wrote up.
14 If you'll remember -- if the panel will
15 remember at the September meeting, Stan and Paul, in
16 particular, recommended that the Chair write a document
17 that could be sent to DPR with our recommendations and
18 conclusions from the mini-workshop. And I said that I
19 would -- wanted to have input from the panel.
20 So we went ahead and wrote a document which
21 you all had for, I think, a reasonable period of time to
22 read and review. I know we've had comments from
23 Roger Atkinson up to this point. And what we would like
24 here is, on a discussion with the agencies -- this is
25 really an internal matter to the panel.
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BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 Basically what I need is for you to give us
2 final recommendations and suggestions so we can then take
3 this document or modified version, send it to
4 Paul Helliker at the agency for their consideration. So I
5 think the best way to handle this would be to go around
6 the room and get people's comments.
7 DR. GLANTZ: Well, I -- I think -- I think
8 it's basically quite good, actually. I think -- and I --
9 the revised draft, which I got a couple days ago, I agreed
10 with many, but not all of the changes. Because I think
11 that some of the changes, while perhaps toning it down a
12 little bit and making it a little bit more palatable
13 politically, have made it less clear.
14 And I just like to go through the specific
15 things that I would suggest we -- I'm working not off the
16 one that we were just handed, but the one that you
17 E-mailed around. Has a red-line, strike-out format.
18 So if you look under part A, number 1, I
19 actually think the original statement that prioritization
20 for the SB50 program has overshadowed -- or no. The
21 original thing which is shown as struck out, "DPR has not
22 used the AB 1807 prioritization method," was -- is just
23 clearer, I think. So I would suggest going back on that
24 one. And the same -- let's see. I want to make sure I
25 didn't --
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BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 DR. BLANC: How about "not appropriately
2 used"?
3 DR. GLANTZ: Well, I don't think they've
4 used it.
5 DR. BLANC: They may have used it in some
6 instances. I don't know. I mean, they may have in some
7 kind of ad hoc way. I don't know, but --
8 DR. GLANTZ: This was discussed endlessly
9 over many years. And we were told over and over and over
10 again that the SB950 program took -- was more important.
11 Maybe if you wanted an intermediary, you could say, "DPR
12 has used SB950 over AB 1807." But I think that's the
13 statement of fact which is correct. And I mean, the
14 other -- the statement --
15 CHAIRMAN FROINES: Stan -- Elinor, can you
16 try -- we'll get the transcript. Can you try and write
17 down what is being said?
18 DR. FANNING: Yeah. I'm, like, making
19 notes.
20 DR. GLANTZ: I don't feel violently about
21 any of these things. Let me just think here. And then
22 number two, I think that the original statement,
23 "Prioritization for SB950 does not necessarily reflect the
24 likelihood of being a toxic air contaminant," is also a
25 clearer statement than --
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BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 DR. BLANC: I'm sorry. Which one is that?
2 DR. GLANTZ: This is number two. I think
3 that was a clearer statement. For number three, I have a
4 third wording. I would say, "The process used to select
5 pesticides for active risk assessment at DPR has not
6 generally taken into account TAC candidate status."
7 CHAIRMAN FROINES: Is that --
8 DR. GLANTZ: That's number three. Huh?
9 CHAIRMAN FROINES: Did you write that?
10 DR. GLANTZ: Yeah.
11 CHAIRMAN FROINES: So you'll give that to
12 us?
13 DR. GLANTZ: Yeah. I mean, these are -- and
14 then let's see. With number five, I just had a question
15 about that. I think that original statement, "In the
16 past, pesticides selected for monitoring did not reflect
17 TAC priorities," is true.
18 The alternative wording, that it "better
19 reflects TAC priorities than in the past," is also true.
20 But in the past, they didn't seem to be paying much
21 attention to them at all, to me. So I would be a little
22 meaner, I guess.
23 The number six, I think the original
24 wording, "DPR does not routinely consider USEPA risk
25 assessments," is a clearer statement than the thing which
29
BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 has been reworded. I think that was it. Let me just
2 look.
3 The other changes that were made were all
4 fine. Oh, and then, if you go to number -- page -- what
5 is my -- page 10, number 4, the -- where we -- it had
6 said -- the original wording was, "DPR should supplement
7 monitoring data," and it was changed to "could." And I
8 prefer "should." So --
9 DR. FUCALORO: Just want to subtract the
10 power of the subjective.
11 DR. GLANTZ: What? Whatever. I think we
12 want to make it affirmative recommendations here. You
13 know, because I think that one of the things that I think
14 came out of the workshop was, you know, trying to
15 couple -- you know, get a better job of getting a handle
16 of what's actually going on.
17 And -- and so, I think we should say
18 "should" there. But those are my -- the rest of it is
19 fine. The rest of the changes were fine. So I don't know
20 if you want to discuss that or just go around the table.
21 CHAIRMAN FROINES: I think if anybody has
22 comments as to what your recommendations are --
23 DR. GLANTZ: I'm keeping Dr. Blanc awake.
24 DR. BLANC: I don't feel strongly about the
25 things you said. I mean, it's fine. Only thing I would
30
BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 say is, that I would defer to the Chair's discretion. If
2 after having heard your concerns, he still chooses in
3 certain of the instances to temper the tone of some of
4 these things, since you're closer on the ground to the
5 likely effectiveness of the document and how it might be
6 impactive, depending upon specific wording.
7 But I think that Stan's general direction of
8 trying to be as explicit as possible, assuming that it
9 wouldn't be counterproductive, is a good general
10 guideline. But you have final responsibility.
11 CHAIRMAN FROINES: And Paul Helliker has
12 heard both comments. He understands that the context --
13 DR. BLANC: Right. I have some specific
14 questions. On page 2, point 2 --
15 CHAIRMAN FROINES: Well, let's go around.
16 Craig?
17 DR. BYUS: Okay. I agree with what Stan
18 said. I'm not totally strong about it, but I think the
19 stronger language is probably the better choice. I just
20 would like to echo the point 2 here about considering a
21 vast approach relisting high priority organophosphates.
22 I really think this is an excellent idea,
23 considering how many organophosphates there are, and the
24 fact that they all do work by a common mechanism. So I
25 really think this is an excellent idea. The
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BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 possibility -- likely -- high likelihood of multiple
2 organophosphates being used on the same crop is, in fact,
3 likely.
4 So I pretty much like the document as it's
5 written. I would like to add, though, that I think that
6 some -- pardon me. Pardon me. That some examination or
7 incorporation of the food residue -- we have all this data
8 somewhere. There is somewhere a lot of data about what
9 pesticides actually are on foods.
10 Now -- and so this could really be a guide
11 for which pesticides are used together. I mean, clearly
12 they had to be used on the same crop. Now, clearly, it
13 wouldn't incorporate all pesticides, because some might be
14 less stable and maybe wouldn't show up in food residue.
15 But there's a lot of multiple-pesticide-use data in the
16 food-residue data somewhere.
17 It could -- could be used to guide
18 prioritizations for -- in terms of multiple risk for
19 multiple pesticides, when they were applied. I tried to
20 find out about some of that information, but I -- when I
21 was doing methyl parathion. But it became just too
22 cumbersome to try to do it. I do think there is a lot of
23 information there about it -- about multiple pesticide use
24 in the food-residue data.
25 CHAIRMAN FROINES: That sounds almost like
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BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 an academic research project.
2 DR. BYUS: It does. It does. But that's
3 all.
4 CHAIRMAN FROINES: Which would be good.
5 DR. BYUS: Yeah. Oh, sure.
6 DR. ATKINSON: Well, talking -- I'd like to
7 also echo the -- that I like the batched approach for
8 listing of chemicals. Certainly makes sense from an
9 environmental-type of approach, as well. Certainly
10 organophosphates, since there isn't a lot of data, they'd
11 be much more easily dealt with as a whole batch.
12 Another thing is, I'd like to -- I certainly
13 endorse the controlled applications, that DPR should do
14 controlled applications for site monitoring, rather than
15 preferably to spending time and energy doing ambient
16 monitoring.
17 CHAIRMAN FROINES: I think that's a very
18 important recommendation. And I think it was made
19 particularly clear by Bob Spear's presentation. And from
20 the standpoint -- again, from the standpoint of
21 identifying a compound as a toxic air contaminant, ambient
22 monitoring has different implications for risk-management
23 purposes. And that's also --
24 DR. ATKINSON: Yes.
25 DR. FUCALORO: As you know, I wasn't at the
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BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 September workshop. I couldn't make it. But I did read
2 this document and noted a few things that some of you
3 noted. The -- the monitoring -- the regulated monitoring,
4 that was a good one. Of course grouping the
5 organophosphates is another one.
6 The one thing I noted -- and I wasn't,
7 again, part of this discussion. This is on page 9,
8 number-one recommendation. Says, "DPR should consider
9 basing TAC listing on application site monitoring results,
10 and using ambient primarily in the risk-management
11 phase." I was just wondering, if that really meant TAC
12 priority listing or does it just mean --
13 DR. BLANC: I think that was the intent. I
14 circled the same thing. Because they don't actually list
15 something as a TAC.
16 DR. FUCALORO: That struck me.
17 DR. BLANC: We recommend that something be a
18 TAC; right?
19 CHAIRMAN FROINES: Yes.
20 DR. BLANC: So that wording needs to be
21 changed to be clearer. It implies that the DPR is
22 identifying -- is from a regulatory point of view listing
23 something as a TAC. Whereas what you're saying is how to
24 do their listing of priorities for consideration as a
25 TAC. Something -- I don't know that being too.
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BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 DR. FUCALORO: Well, their priority list --
2 I think that's become a common language with ARB and DPR,
3 the priority list in which chemicals are used and go to
4 next in order to see if we are going to designate them as
5 TACs.
6 CHAIRMAN FROINES: Well, the -- this goes
7 back in history to the -- to the debate that we've had
8 with DPR since the mid '80s where we have always strongly
9 disagreed with DPR on -- on the MOE as the basis for a TAC
10 listing.
11 We've always taken the position that a
12 compound should be designated as a toxic air contaminant
13 based on its toxicity. And that's different than the DPR
14 position. So that this recommendation for application
15 site monitoring is, in essence, to -- to -- is in essence
16 saying, if you're going to use the MOE, then we think
17 application site monitoring is the most appropriate
18 approach to that for purposes of identifying TACs.
19 DR. FUCALORO: And this highlights the
20 difference of what I think ARB does and DPR, on the other
21 hand. ARB will look at potency factors in some way and
22 designate something a TAC, and then use exposure as part
23 of mitigation; right?
24 Whereas DPR brings exposure in also --
25 exposure and potency factors, whatever they are, cancer or
35
BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 noncancer effects, and then uses that as a basis for
2 designating something a TAC. But both, organizations as
3 far as I understand, use both of those in order to set up
4 a priority list. I think -- I think I have -- I think I
5 have that right.
6 CHAIRMAN FROINES: The problem, of course,
7 with the ambient monitoring, leaving aside the variability
8 issue is, you can go back to the data that is available
9 for us to review on methyl parathion and the actual
10 monitoring data that was available was very limited. So
11 we ended up, I think, used Jim Seiber's data, which was
12 one study from the '80s.
13 I mean, it's -- it's really, when you base
14 major policy and scientific decisions on one study done in
15 1988, 1987, and that forms the basis of whether
16 something's a TAC or not, you realize the limitations of
17 that approach.
18 So if we had lots of data that dealt with
19 variability, that's a different issue. But in any case,
20 to the degree that we continue this approach with the MOE,
21 then application site monitoring becomes obviously the
22 preferred approach, at least from the standpoint of this
23 panel. Paul?
24 DR. BLANC: I have a number of text changes
25 I'll just pass on to your colleague. But let me ask you
36
BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 my substantive questions. In page 2, point 2, the last
2 line, "Further, the SB950 process does not use a
3 quantitative ranking scheme."
4 CHAIRMAN FROINES: Where are you at?
5 DR. BLANC: The last line of section 2, on
6 page 2, you know, "The criteria used to prioritize SB950
7 differ from those articulated by DPR." In that section,
8 the last line. "Further, the SB950 process does not use a
9 quantitative ranking scheme." I just wanted to be clear
10 on that. Do you mean you're not referring therefore to
11 their priority list, which did have some kind of rank?
12 CHAIRMAN FROINES: No. They have this
13 committee, remember?
14 DR. BLANC: Right.
15 CHAIRMAN FROINES: And the committee
16 basically defined the priority, and that they're not, in
17 essence, using this document for prioritization. This is
18 the quantitative document that effectively is not being
19 used.
20 DR. BLANC: Okay. And when they -- you --
21 you -- I think it was a little confusing, because they --
22 they rank things in three groups or something; right? So
23 it is -- it's very roughly a semi-quantitative. But it's
24 not the -- there's no process to it. It's two separate
25 issues to me.
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BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 And the stronger one is not that they -- not
2 so much that they group things in the three groups, you
3 know -- bad, very bad, and better -- but that there is no
4 rationally articulated process by which they do that. And
5 I thought that needed to be stated more clearly.
6 And I wondered, in fact, if on -- and this
7 is the related point, I think, in terms of recommendations
8 on page 5, where it says -- current language is -- the
9 third point is, "Develop a policy for coordination of
10 priorities under different programs that require DPR to
11 prepare risk assessments for pesticide." That's getting
12 at this process; right?
13 And what I would rather explicitly say, that
14 they need to delineate explicite criteria for ranking,
15 rather than the currently used ad hoc procedure. Because
16 of all of the things we heard, that was, for me, the most
17 disturbing, was that there could not -- maybe they have
18 something. But they could not explain it to me in a way
19 that sounded coherent.
20 That there was actually -- so I don't mean
21 that they have to prepare a 500-page document. But they
22 need to have a clearly delineated process. And I think we
23 need to say that.
24 CHAIRMAN FROINES: Does everybody agree with
25 that recommendation?
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BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 DR. BLANC: I mean, I wouldn't make it as a
2 new point, necessarily. But I think that's the point I'm
3 trying to get at. I also thought that -- going back
4 earlier, back to page 2 on point 3 where it says -- the
5 point that has to do with, "The process used to select
6 pesticides for an active risk assessment does not
7 necessarily take into account TAC candidate status." And
8 I would say that the decision --
9 CHAIRMAN FROINES: I'm sorry. Where are
10 you?
11 DR. BLANC: Point 3, on page 2. And I would
12 say that the problem is not that they don't seem to be
13 guided by a specific policy approach. I think they're not
14 guided by a coherent policy. It's not the lack of
15 specificity that bothers me so much, it's that it's
16 incoherent.
17 And similarly, on point 4 on the next page,
18 it's not that the process used to select pesticides for
19 air monitoring has been distinct from the risk assessment,
20 it's been disconnected from the risk assessment. I notice
21 you use the word "disconnected" later, but I really think
22 that that's --
23 On page 4, point 6. Well, after point 6.
24 These six points summarize the information which was
25 presented in that first part. And you get into this in
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BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 the second half. But the fact that the changing-use
2 patterns are not incorporated in a timely fashion to
3 priority setting, it's emphasized a lot in the sampling.
4 But I thought it was a critical issue that came up
5 relevant to the priority setting, as well.
6 Now, going on to the next section. In terms
7 of the -- the next set of -- next set of recommendations,
8 on the batching the organophosphate pesticides, this is a
9 technical question -- two technical questions. One is, do
10 we need to specify cholinesterase inhibiting
11 organophosphates?
12 The reason I ask, I know there are
13 carbamates which are not cholinesterase inhibiting and are
14 used for other purposes. Are there any -- technical
15 question for DPR. Are there any organophosphates which --
16 whose principal means of action is something other than
17 cholinesterase inhibiting?
18 CHAIRMAN FROINES: Well, there is the issue
19 of --
20 DR. BLANC: I'm going to get to the --
21 just --
22 DR. PATTERSON: I'm Gary Patterson from
23 DPR. And, no. It's -- organophosphates by nature are
24 cholinesterase inhibitors.
25 DR. BLANC: So unlike the carbamates, some
40
BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 of which --
2 DR. PATTERSON: Diatomic carbamates usually
3 are not.
4 DR. BLANC: Right. Okay. Fine. But I do
5 think we may need this -- this section to say something
6 about organophosphates with delayed neurotoxicity.
7 Because in the batching process, we're certainly going to
8 have to take into account whether within those
9 organophosphates, any of them have delayed neurotoxicity.
10 Thanks.
11 And I thought that point 3 is really what
12 you really -- what we're really trying to say. They need
13 to delineate specific criteria for ranking rather than the
14 currently used ad hoc procedure. I think I said that
15 already. Okay. In Dr. Spear's comments --
16 CHAIRMAN FROINES: What page are you on?
17 DR. BLANC: Page 8. Under the heading,
18 "Ambient monitoring may not result in useful
19 characterization of population exposure." You have here
20 his critique of the ambient air monitoring, but not
21 necessarily alternatives that he also suggested.
22 And since you've come back to that in the
23 recommendations, invoking him. I guess, one question that
24 I have is, aside from the comment and discussion about
25 sampling in control applications, didn't Dr. Spear also
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BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 talk about the importance of modelling -- of theoretical
2 modelling exposure?
3 CHAIRMAN FROINES: Yes.
4 DR. BLANC: And there's no recommendation
5 here in -- A -- A, it's not described here. But B,
6 there's no follow-up recommendation that says that, in
7 addition to these other things, models of exposure should
8 also be used in estimating.
9 DR. ATKINSON: Point 5, the last sentence
10 has -- computer modelling is mentioned.
11 DR. BLANC: Where is that?
12 DR. ATKINSON: Same page.
13 CHAIRMAN FROINES: Last sentence of number
14 5. Page 8, last sentence.
15 DR. ATKINSON: That's just mentioned.
16 DR. BLANC: I'm sorry. Page 8, point 5?
17 CHAIRMAN FROINES: Last sentence.
18 DR. BLANC: Under "Currently proposed
19 changes to the ambient monitoring program may increase the
20 time required." Maybe -- page 8.
21 DR. ATKINSON: Page 8, point 5.
22 CHAIRMAN FROINES: Last sentence in the
23 paragraph under 5.
24 DR. FUCALORO: It says -- starts with "Other
25 ideas under consideration."
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BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 DR. BLANC: (Reading.) Well, I think you
2 should -- I think it got lost in the shuffle, because I
3 thought it warranted being a separate --
4 CHAIRMAN FROINES: Yeah, I think it could be
5 made more explicit. Take your results of application site
6 monitoring and use dispersion models for predicting
7 ambient concentrations.
8 DR. BLANC: Okay. Those were my --
9 CHAIRMAN FROINES: It's all good.
10 Everybody's fine with that? Peter?
11 DR. WITSCHI: Yeah. Not much to add, except
12 I picked up on Spear's point which says, "very limited
13 value." So first question must come to mind, why are we
14 doing it at all? The second one comes -- comes out like
15 Mark Twain in the weather, everybody complains about it,
16 but nobody's really doing something.
17 And I think what's really missing is some
18 overall master plan or great view of how the whole
19 exposure assessment could be improved so that it can serve
20 the purpose we would like things, and that's the
21 health-risk assessment.
22 Because the way I've seen -- this includes
23 this morning's presentation, that was very good. But we
24 are going to monitor more and more without really having a
25 clear view of what is going out to be, and for --
43
BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 CHAIRMAN FROINES: Well, I think that DPR
2 has requested that we assign a panel member or more to
3 work with them on -- on these recommendations. And
4 certainly the issue of exposure-assessment monitoring
5 would be one of the question features.
6 Now, what I did was to propose that
7 Elinor -- Dr. Elinor Fanning, who's working with the
8 panel, and who has more time than the panel members to
9 work with them. But I -- but I think that we need to
10 assign at least one or two people to work with DPR to
11 address precisely the kinds of questions that you're
12 raising.
13 And so, if I can use your comments -- I wish
14 Stan were in the room. We -- it would be good to have a
15 volunteer or two to agree to work with DPR on the issues
16 that arise out of this document. And I think that the two
17 people who are missing are not the appropriate people for
18 this. I think it takes people who have some more
19 knowledge of exposure-related issues.
20 So I think this group here today is actually
21 the best. And if nobody wants to volunteer, I'll just
22 take that as -- take that silence as silence and then
23 we'll work it out outside, you know, the lights of the
24 meeting. Or we can assign Stan, because he's not in the
25 room.
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BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 DR. BLANC: And he's leaving early. So he
2 should be punished.
3 CHAIRMAN FROINES: So hearing no volunteers,
4 we'll take it up after the meeting. Anyway, go ahead,
5 Peter.
6 DR. WITSCHI: That's about all. I'm still
7 puzzled. I still do not see any good way how the human
8 data can be used for human health-risk assessment. And I
9 also see that we are doing more and more, which is going
10 to be less and less useful for this purpose.
11 CHAIRMAN FROINES: Well, this is a specific
12 example of a major problem, as you know, about how
13 monitoring data is used in air pollution exposure
14 assessment. It's one of the -- it is one of the -- it
15 is -- it is basically the first-stated priority by the
16 National Academy of Scientists, committee on Particulate
17 Matter. So it's a key issue.
18 So I think that we're finished with this.
19 We'll take all these suggestions -- we'll take all these
20 suggestions and develop a final document and send it off.
21 I don't know, Paul, if there's anything that you heard
22 this morning that makes you want to comment now or you
23 want to just wait till you receive the actual, formal
24 document. But it's your call.
25 MR. HELLIKER: My make of it is, I think
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BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 this is an excellent document, and it will help guide us
2 as we go forward. And as you just mentioned, there are
3 some fundamental problems that we face. And we will seek
4 your input and your assistance in helping to make a
5 reasonable choice as we go forward in all of our
6 regulatory programs.
7 But, I appreciate this. And certainly it
8 reflects some of my impressions, as I've come into the
9 department, that we do need to be clearer in defining for
10 you, as well as for other stakeholders out there, as what
11 our processes are, that we've gone through in making
12 decisions about the prioritization about different
13 monitoring and different risk assessments. So I'm looking
14 forward to responding to this.
15 CHAIRMAN FROINES: Thanks. Okay. Do we
16 want to take a break? Don't you? Just for everybody, got
17 a note from Peter that Stan was on the phone. We'll take
18 a ten-minute break.
19 (Brief recess taken.)
20 CHAIRMAN FROINES: The next item on the
21 agenda is MITC. This will be a staff report from DPR.
22 The panel will not take up the document today for
23 discussion purposes. That doesn't mean that we can't ask
24 questions as the presentation is made. And you're welcome
25 to do that.
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BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 But in terms of our formal -- a formal
2 discussion of the document, that will happen at our next
3 meeting, and we will have the benefit at that time, also,
4 of the OEHHA comments, which we currently don't have. And
5 we'll also have the benefit of Peter Witschi's final --
6 final review.
7 So those two things are -- because they're
8 still outstanding, I want to not try to take it up. Also
9 the -- before we start on MITC, I have overlooked saying
10 something at the beginning that I want to catch up and say
11 thank you very much to Tony Fucaloro for hosting us here.
12 DR. FUCALORO: Actually, the thanks goes to
13 the staff of Athenaeum. They are very competent and very
14 helpful. I'll transmit that thanks to them.
15 CHAIRMAN FROINES: If you have any comments
16 you want to say about the history and anything else,
17 please feel free.
18 DR. FUCALORO: Yeah, but I'll probably get
19 it wrong. It's been told to me several times, and I'm not
20 sure I have it right. But this is a product of one of our
21 founding -- one of CMC's founders, Donald McKenna, who
22 recalls having students and faculty together for teas and
23 dinners at -- when he was a student at Pomona College.
24 So he tried to get that -- that to happen at
25 Claremont McKenna College, and he was successful. And
47
BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 under Jack Stark raised money for this -- this building,
2 and to raise the funds to endow it.
3 So four nights a week, for example, we will
4 have a something -- we'll have -- similar to what you're
5 doing tonight, which we'll have a reception, we'll have a
6 dinner, and then a presentation in this main hall. And
7 students and faculty from all the colleges, whether they
8 have meal plans or not, eat for free.
9 And that's all endowed. And so it's quite a
10 program. Runs four times a week during the academic
11 year. So it's a great facility, and it brings faculty and
12 students together. And it's not a faculty high house --
13 high table as you would find at another institution.
14 Almost all events, with the exception of a few like this
15 one, require students' attendance and student
16 participation. So that's pretty much the philosophy and
17 the thinking behind this -- this program -- the Athenaeum
18 program.
19 CHAIRMAN FROINES: Well, thank you again. I
20 think it's lovely.
21 DR. GLANTZ: Where did the name come from?
22 DR. FUCALORO: Well, I was ambushed to give
23 a history of this place, and you're asking about -- I know
24 there's a city named Athens --
25 DR. GLANTZ: Okay.
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BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 DR. FUCALORO: -- that goes back to
2 antiquity and has quit a history. But beyond that, I'm a
3 chemist. What the heck?
4 DR. GLANTZ: Well, would you find out and
5 report back at the next meeting?
6 DR. FUCALORO: I know there's an Athenaeum
7 at Cal Tech -- at Cal Tech.
8 CHAIRMAN FROINES: This is not a graduate
9 student's oral, and you don't keep asking them questions
10 till you find the one he doesn't know the answer to.
11 DR. PATTERSON: We only do that to DPR.
12 CHAIRMAN FROINES: Okay. MITC.
13 DR. PATTERSON: Again, I'm Gary Patterson
14 from DPR. Paul Goslyn is unable to attend this meeting,
15 and he sends his apologies. And few statements that he
16 wanted me to start with was, he wanted me to emphasize the
17 importance of your input on MITC, and that it will be used
18 to help guide us through the risk-management phase for
19 this chemical.
20 In addition, he's very interested in hearing
21 your thoughts on the sensitivity of the end points that
22 will be presented today. And on one side note, we gave
23 you a list of four chemicals that we were going to do for
24 the year. We're going to replace naled with
25 chlorpyrifos.
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BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 And with that, then, I'll turn it over to
2 staff to make a presentation. The first person will be
3 Pam Wales to do the environmental fate.
4 MS. WALES: Good morning. My name is
5 Pam Wales. I'm with the Environmental Monitoring and Pest
6 Management Branch at DPR. And -- next slide. I'm going
7 to very briefly cover the valuation of MITC as a TAC on
8 the environmental fate of this chemical.
9 The three points that I'm going to cover
10 very briefly this morning are: The fate of MITC and the
11 environment, and focusing mostly on the air; the use in
12 California; and also cover some air monitoring to
13 determine levels of MITC following applications.
14 When we talk about MITC, we're really
15 talking about three pesticides. MITC, on the bottom of
16 the slide, is registered in California for use as a wood
17 preservative. Use in California is about 350 pounds per
18 year. MITC is very volatile. Its vapor pressure is about
19 16 millimeters of mercury, and the Henry constant is at
20 1.8 times 10 to the minus 4 atmospheres, cubic meters per
21 mole.
22 MITC is used to control wood decay
23 organisms in large structural timbers. It's typically not
24 used in crop-land setting. However, there are two other
25 pesticides. One is called Dazomet, and the other
50
BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 Metam-Sodium, for which MITC is the principal active in
2 their formulations.
3 Dazomet is registered for use in California
4 as a slimicide and biocide. It's used in cooling water
5 treatments and also in -- just had a brain fade. Also,
6 one product is used as a pre-plant fumigant. The use of
7 Dazomet is about 20 thousand pounds per year, and it
8 breaks down to form MITC.
9 Metam-Sodium, on the other hand, is
10 registered for use as a pre-plant fumigant, wood
11 preservative, and also for root control. And in
12 California, in the agricultural setting, almost 16 million
13 pounds are used per year. While Metam-Sodium itself is
14 non-volatile, it does break down rapidly to MITC.
15 Next slide. As I've said, the primary
16 source of MITC in the environment is from the breakdown of
17 Metam-Sodium. Metam-Sodium is applied to a soil either
18 by soil injection or by chemigation. It's usually --
19 DR. GLANTZ: What is chemigation?
20 MS. WALES: Chemigation is irrigation --
21 treatment by irrigation.
22 DR. GLANTZ: Does that mean put it in the
23 irrigation water or they just spray it on?
24 MS. WALES: Yes, put into irrigation water
25 then spray it out over the field. When it's applied by
51
BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 chemigation, after the treatment, a -- enough clear water
2 is ran afterwards through the sprinklers to produce a
3 one-inch seal of water, and also to drive the Metam-Sodium
4 into the soil.
5 When it's injected by soil-injection
6 methods, use special equipment that injects it about 10 to
7 12 inches into the soil. Afterward, the soil is bedded or
8 tarped or rolled and compressed. The purpose of this is
9 to keep the Metam-Sodium -- actually, the MITC vapors in
10 the soil so they actually do the fumigant activity.
11 The conversion in the soil of Metam-Sodium
12 to MITC occurs within about an hour. And conversion
13 occurs with 87 to 95 percent efficiency, depending on some
14 conditions of soil. Increased soil temperature, increased
15 concentrations of clay or organic materials, and increased
16 soil pH, coupled with decreased soil moisture content,
17 lead to rapid -- more rapid conversion.
18 Two other compounds may be formed in the
19 soil during that conversion. One is carbon disulfide and
20 the other is hydrogen sulfide. The generation of those
21 compounds really depends on the pH of the soil. If it's
22 more alkaline, hydrogen sulfide is expected to be
23 generated. And in basic soils, carbon disulfide.
24 About 60 percent of the MITC that's
25 generated in the soil volatilizes, leaves the soil and
52
BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 enters the air. Once in the air, the main pathway for the
2 loss of MITC from the air is through photolysis. The
3 photo decomposition results in a variety of compounds, as
4 you can see on this overhead here.
5 MITC is there on the left. The activated
6 molecule is the one in the middle with the star. And
7 according to Geddes, the major, primary photochemicals
8 produced is methyl isocyanide. About 80 percent of the
9 MITC is converted to methyl isocyanide.
10 That follows some secondary photochemical
11 processes and results in methyl isocyanate, and
12 methylformamide, and some other compounds which you see
13 here. Geddes proposed that the -- the methyl isocyanate
14 may be the -- may be photochemically stable, because he
15 observed that it increased over time.
16 Next page. Briefly to cover the use of
17 Metam-Sodium --
18 DR. BLANC: Can you go back to the last
19 slide?
20 MS. WALES: Sure.
21 DR. BLANC: Point out to us which
22 formulas -- which moiety --
23 MS. WALES: I'm sorry. I can't hear you.
24 DR. BLANC: Which chemical structure is
25 which?
53
BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 MS. WALES: If you follow the main pathway,
2 that's MITC.
3 DR. BLANC: Yeah.
4 MS. WALES: That's MITC, the activated
5 state. To the right of that is methyl isocyanide. To the
6 right of that is methyl isocyanate. A-ha. This structure
7 right here is N-methylformamide. This right here is
8 methylamine. Methylamine is also generated in this
9 pathway. This is carbonyl sulfide, sulfur dioxide, and
10 in this pathway, you also generate the MIC plus hydrogen
11 sulfide.
12 DR. BLANC: Thank you.
13 MS. WALES: This is -- this slide shows
14 overall Metam-Sodium use in California. This is, once
15 again, in the agricultural setting, from 1990 through
16 1998. As you can see, Metam-Sodium use began to increase
17 in 1994. It is pretty-well stabilized at about 15 to 16
18 million pounds a year since then.
19 The reason for this increase in 1994 was
20 largely due to two things. One was the reduced use of
21 telone, 1-3 dichloropropene, which is another fumigant,
22 and methyl bromide. Also, researchers discovered that
23 Metam-Sodium was very effective in controlling root
24 nematodes in carrots, and also nightshades in the
25 nightshade crops. So they applied -- so use went up to
54
BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 account for that.
2 Next slide. This is the use of Metam-Sodium
3 from 1990 to 1998 on a month-by-month basis. You can see
4 that it's used pretty much year round. However, there are
5 couple large peaks. The first one, right here in February
6 through April. And another peak that occurs in the late
7 summer, early fall, from about July through October. And
8 this is throughout the whole state.
9 As I said, Metam-Sodium is primarily used on
10 carrots. Almost 30 percent of what's applied in
11 California is used on carrot crops. Another 25 percent --
12 23 percent is used on tomatoes, cotton, and potatoes
13 account for the major crops. All the rest of the uses are
14 from a variety of crops -- root crops, bulb crops, lots of
15 different crops.
16 When we say that the use is associated with
17 a crop, it's actually a pre-plant application. It's
18 applied before the crop is put in the ground. This map
19 shows how Metam-Sodium is used throughout the state. This
20 is from 1998 --
21 CHAIRMAN FROINES: Question.
22 MS. WALES: Uh-huh.
23 CHAIRMAN FROINES: This document that we had
24 earlier this morning, Monitoring Multiple Chemicals by
25 Crop Root, and he's got the 23 chemicals for cotton.
55
BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 MS. WALES: Uh-huh.
2 CHAIRMAN FROINES: And Metam-Sodium is not
3 listed on this list. So there's a disconnect between your
4 11 percent here, and this document. Which seems -- would
5 seem to imply that -- well, they're different. Anybody
6 know the answer to that?
7 MR. SEGAWA: I do.
8 CHAIRMAN FROINES: Oh, there you are. I
9 keep looking for you.
10 MR. SEGAWA: That's because, in the chemical
11 listed for cotton, I only listed those chemicals which had
12 their highest use on cotton. And in this particular case,
13 you can see that highest use is on carrots. And so in the
14 crop grouping, it would have been grouped with carrots,
15 rather than cotton.
16 CHAIRMAN FROINES: Okay. For us, it's
17 probably better to know which is the highest pesticides on
18 cotton.
19 MR. SEGAWA: Yes. For instance, we could
20 have one -- I just put the highest crop use. I could have
21 put highest two or highest three crops, which would have
22 been another way to do it.
23 CHAIRMAN FROINES: Well --
24 DR. GLANTZ: Well, no. I think the
25 difference -- I think what you're saying, John, is the
56
BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 list should have been a list of the -- of the pesticides
2 used on cotton, perhaps. And what he did was, he said,
3 let's look -- it was the other way around.
4 It said, let's look at the pesticides and
5 pick the crop that each pesticide is used the most on.
6 And those are the -- the ones on the list we had earlier
7 were the pesticides where cotton was the most heavily --
8 was the greatest use of that pesticide.
9 CHAIRMAN FROINES: But you see the potential
10 contradiction?
11 DR. GLANTZ: Yeah, yeah. I just think you
12 need to be clear, though.
13 CHAIRMAN FROINES: So we -- so the panel,
14 you see, doesn't know right now what are the most
15 important pesticides on cotton.
16 DR. BLANC: Because -- to follow up on that,
17 you could have a pesticide which actually isn't used that
18 much anywhere, but the one crop that it is used on is
19 cotton; right?
20 MR. SEGAWA: Correct.
21 DR. BLANC: And another pesticide which is
22 used, like Metam-Sodium is -- only ten percent of it's
23 used on cotton, but it happens to be one of the most
24 widely used pesticides in California. Therefore ten
25 percent of 13 million pounds is still a million pounds
57
BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 used on cotton.
2 MR. SEGAWA: That's correct.
3 DR. BLANC: And so, therefore, what would
4 probably interest us more would be, of the heaviest-use
5 pesticides overall in California, which are -- which of
6 them are used in rank order in cotton? So that if you
7 talked about one crop --
8 MR. SEGAWA: Yes, but then we would have to
9 come up with some sort of cut off. As you say, one
10 million pounds -- everything above one million pounds, we
11 have concerns about. Everything below, we do not monitor
12 for.
13 DR. GLANTZ: Or some reasonable cut off.
14 Just show us -- or show us if you use a cut off of one
15 million pounds, then you use it to cut off 500 thousand
16 pounds. How does it change?
17 CHAIRMAN FROINES: I mean, we're interested
18 in the scope of the problem. And so, if you arbitrarily
19 limit that, we're left without a real sense of what --
20 what's the pattern of use, basically. Let's go on.
21 MS. WALES: Next slide. Map of the 1998
22 use in California. This is of Metam-Sodium. So you can
23 see the bulk of the Metam-Sodium is applied, once again,
24 through the Central Valley. Heaviest -- these darkest
25 spots are the highest use.
58
BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 The highest use is in Kern County. This is
2 1998 now. We have Kern County, and then up through
3 Fresno, that's quite a bit in Madera area. And then on
4 down here in Imperial County. But you can see, it's
5 also -- it's used pretty much through all the agricultural
6 areas. Including, if you look up at the north part of the
7 map there, you'll see some use on the potatoes up in Modoc
8 and bulbs, I believe, in Del Norte.
9 Now, these things that I've mentioned about
10 the locations of where it's used and also the soil
11 conditions actually played a big part in determining where
12 we wanted to do our studies. The ambient studies were
13 designed to measure pesticide concentrations in ambient
14 air during the time and region of peak use.
15 The samplers were placed on roof tops of
16 schools, fire houses, and other public buildings. And for
17 ambient studying -- studies, we did not associate the
18 monitoring with any specific application. This was to
19 provide an estimate of exposures that people living in
20 proximity to pesticide applications might experience.
21 Three studies were conducted in California,
22 and they're summarized in the report. This is a table
23 with the information from the three studies. I'm not
24 going to read this to you in the interest of time. And
25 especially since Tom, who's after me, is going to cover a
59
BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 lot more of this in exposure assessment.
2 What I did want to point out to you, was
3 that the ambient studies were conducted in Kern County,
4 and in Lompoc, and then again, very new study that was
5 just published this year in Kern County. And these were
6 conducted in the summertime.
7 Dr. Seiber's study went from May until
8 August, and then the Air Board study was in July. And in
9 Kern County, we have soils in the summertime that are very
10 warm. They're dry. The pH is a little bit on the
11 alkaline side. And the soil-moisture content is low. And
12 so that would indicate that that's probably the best time
13 to find MITC in the air.
14 These are the positive-sample results. And
15 the number of samples that were taken and then the number
16 of samples -- of the positive samples. This recent study
17 by Dr. Seiber did something a little different than the
18 others did. And that was, he put monitors inside
19 residential homes, outside residences, very close to the
20 external walls of the homes.
21 And then he also placed monitors on tops of
22 roof tops, other public buildings in the Kern County area
23 where Metam-Sodium was being applied. Interesting thing
24 to notice is that the positive detections indoors was not
25 that much different from the outdoors, and the ambient
60
BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 studies or ambient samples.
2 In the wintertime, he took samples in
3 January and in March. And now, those cool air/cool soil
4 conditions, and the results are much lower than what they
5 were in the summer studies. This is a map from the study
6 that was conducted by the Air Board of 1993. Hard to see,
7 because it's not on the scale here.
8 But the samplers were placed in Shafter and
9 Bakersfield, in Lamont, and Weed Patch. The red hashed
10 marks and checker-board marks that you see here on the map
11 are where the applications of Metam-Sodium occurred during
12 this study.
13 As you can see, we had applications
14 surrounding all of the areas. An interesting thing that I
15 noted was that at Bakersfield, which was the background
16 site, there were positive detections in all eight of the
17 samples that were collected. And the nearest applications
18 of Metam-Sodium were approximately six miles to the
19 northeast -- or to the northwest, and about seven or eight
20 miles to the southeast.
21 CHAIRMAN FROINES: On your previous
22 overhead --
23 MS. WALES: Uh-huh.
24 CHAIRMAN FROINES: -- you say "ambient air
25 monitoring, MITC." My guess is that you mean
61
BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 Metam-Sodium.
2 MS. WALES: We're monitoring for MITC after
3 applications of Metam-Sodium. Because Metam-Sodium is not
4 volatile, we don't expect to find it in the air. Also,
5 because conversion is so rapid, yes.
6 CHAIRMAN FROINES: But it's a Metam-Sodium
7 application.
8 MS. WALES: It's a Metam-Sodium
9 application. One other thing to note, I checked. There
10 was no Dazomet or MITC applied anywhere in Kern County
11 during the course of the study. So all of the results
12 would presumably be from the Metam-Sodium applications.
13 This is from the Lompoc study. Now, while
14 this study wasn't conducted solely for Metam-Sodium, one
15 of the chemicals was Metam-Sodium. There were -- samplers
16 were placed at these locations around the city of Lompoc.
17 And two applications were made during the study, one right
18 here, and the other one is right here.
19 DR. FUCALORO: Just one question. Came up
20 when I was reading the report. A -- AI, what does that
21 stand --
22 MS. WALES: Active ingredient.
23 DR. FUCALORO: Thanks.
24 MS. WALES: Okay. On the application site
25 air monitoring studies --
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BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 DR. GLANTZ: Before you go on, on this
2 figure 11-A, I'm a little confused.
3 MS. WALES: The Lompoc map; okay.
4 DR. GLANTZ: Yeah. Where -- were the -- is
5 this whole gray area where it was applied? That's the
6 city of Lompoc; right?
7 MS. WALES: Yeah. Let's go back to that
8 map.
9 DR. GLANTZ: So where is the actual -- is
10 the actual application a little box sort of on the --
11 MS. WALES: Yeah, on the map here, it's
12 purple. This is the city of Lompoc. This is where one
13 application occurred.
14 DR. GLANTZ: I see.
15 MS. WALES: That was the 1,058 pounds were
16 applied. And then this field right here to the -- almost
17 due west --
18 DR. GLANTZ: I see. Okay.
19 MS. WALES: -- is the 952. For the
20 application site monitoring studies, we have five studies
21 that were conducted, and they're summarized in the
22 report. Once again, I'm not going to -- on the next slide
23 I have a table. I'm not going to read all this again.
24 However, two of the studies were from --
25 were based on sprinkler irrigations. One of them we
63
BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 monitored for MITC, hydrogen sulfide, and carbon disulfide
2 following a sprinkler irrigation application. And then
3 these are the results.
4 Tom is going to discuss this a lot more
5 following me, so I'm not going to say much, other than we
6 did detect hydrogen sulfide. And that could be expected
7 because of the alkaline of the soil. And we did not
8 detect carbon disulfide.
9 Three studies were done following soil
10 injection. One in 1993, one in 19 -- all three -- well,
11 two in 1993, and one in 1995. And once again, following
12 the application, MITC was detected in all of the
13 samples -- nearly all of the samples in all of those
14 studies. There are no questions? Tom.
15 CHAIRMAN FROINES: Thank you.
16 MS. WALES: Thank you.
17 DR. BLANC: Actually, I have one question.
18 Sorry.
19 MS. WALES: Oh, okay.
20 DR. BLANC: Because this may not be covered
21 later.
22 MS. WALES: Okay.
23 DR. BLANC: Your third overhead --
24 MS. WALES: The third one?
25 DR. BLANC: -- where you talked about the
64
BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 structure of Metam-Sodium and Dazomet.
2 MS. WALES: Okay.
3 DR. BLANC: So is the -- should I assume
4 that each molecule of Dazomet yields two molecules of MITC
5 as opposed to Metam-Sodium on the one-for-one basis?
6 MS. WALES: According to the manufacturer
7 of the one -- of one of the Dazomet products, when Dazomet
8 breaks down, there's a ring --
9 DR. BLANC: Rearrangement?
10 MS. WALES: Well, a ring break that occurs.
11 And you yield one molecule of MITC, one molecule of
12 formaldehyde, one molecule of hydrogen sulfide, and one
13 molecule of methylamine, I believe. And together, that
14 whole collection of compounds constitutes the active.
15 DR. FUCALORO: In the presence of water;
16 right?
17 MS. WALES: In the presence of water, yes.
18 DR. BLANC: Say it again. One molecule of
19 MITC, one molecule of formaldehyde --
20 MS. WALES: Of formaldehyde, one molecule
21 of hydrogen sulfide, and one molecule of methylamine, I
22 believe. Let me check to make sure. Yes. Formaldehyde,
23 MITC, hydrogen sulfide, and mono-methylamine.
24 CHAIRMAN FROINES: What is it again?
25 MS. WALES: I'm sorry?
65
BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 CHAIRMAN FROINES: Say it again.
2 Methylamine --
3 MS. WALES: MITC, formaldehyde, hydrogen
4 sulfide and mono methylamine.
5 DR. BLANC: What's the form of formaldehyde?
6 CHAIRMAN FROINES: CH2O. There are two
7 formaldehydes.
8 MS. WALES: You would get two?
9 CHAIRMAN FROINES: You said methylamine,
10 MITC, H2S and formaldehyde.
11 MS. WALES: Yes.
12 CHAIRMAN FROINES: Seems to me you get two
13 formaldehydes. What am I missing here?
14 DR. BLANC: You got to get something
15 different, because there's five carbons in this molecule.
16 CHAIRMAN FROINES: You get MITC, H2S,
17 methylamine --
18 MS. WALES: And formaldehyde.
19 CHAIRMAN FROINES: So you have to have two
20 formaldehydes.
21 MS. WALES: That could be.
22 CHAIRMAN FROINES: Break the bond between
23 the -- you look at the sulfur. You break the bond between
24 the two sulfur breaks, break the bond between the
25 hydrogen, the methylamine, you can see you take that right
66
BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 out. See, the MITC is the right-hand side, so you've got
2 two carbons unaccounted for. So that must mean two
3 formaldehyde.
4 MS. WALES: That could be.
5 CHAIRMAN FROINES: I'm sorry. Thank you.
6 MS. WALES: Is that good? Thank you.
7 DR. THONGSINTHUSAK: My name is
8 Thomas Thongsinthusak. I'm with DPR. My presentation
9 will come -- will cover part B, the exposure assessment of
10 the MITC. Next one, please. My presentation will cover
11 six different topics, starting from estimate production of
12 MITC in California and the calculated exposures for adults
13 and children. And so I touch on the production of MIT,
14 hydrogen sulfide, and then exposure appraisal.
15 Next please. Estimated production of MITC
16 in California. I use the -- use report format and sodium
17 from 1992 to 1997 and the amount of Metam-Sodium, MITC are
18 shown as million pounds. The first column, Metam-Sodium
19 use in California in 1992, is about 8.6 million pounds.
20 And the amount was doubled in about 1995.
21 This is the column show the MITC generated
22 from Metam-Sodium use. This column here. I use the
23 equation shown in foldout B. The conversion of
24 Metam-Sodium to MITC is about 60 percent by weight, which
25 is about one mole of Metam-Sodium per one mole of MITC.
67
BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 The amount of MITC products used in California is very
2 low. For 1992, it's about 8,500 pounds. In 1997, it's
3 about 400 pounds, only.
4 In the last column show the total estimate
5 amount of MITC produced from '92 to '97. The last part of
6 this slide show the amount of use of the estimate in
7 California. Which is -- California, which is very small
8 compared to amount use of Metam-Sodium.
9 Next slide, please. This slide show the
10 calculation of the exposure estimates calculated for
11 adults and children. The -- first of all, I use the data
12 from what Pam mentioned, and then those of amount of
13 concentration of MITC were adjusted for molecular weight,
14 and application weights, and a percent recovery.
15 First of all, I use the MITC concentration
16 times the maximum application rate, divided by the
17 application rate, if known or used in the study, and then
18 divided by percent of self-recovery. I can convert from
19 the amount expressed as microgram per cubic meter to parts
20 per billion using this equation.
21 The estimate calculated as an observed daily
22 dosage or ADD. For ADD I use the short-term concentration
23 of MITC times adult female ventilation rate and divided by
24 body weight. Short-term ADD concentration, that means 24
25 hour times average or closest to 24 hour TWA. Further
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BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 exposure estimates for male -- adult males, I can use the
2 factor of 1.5, which is obtained from the ratio of
3 ventilation rate and body weight between males and
4 females.
5 The next is the long-term or moderate-term
6 exposure estimates for MITC or seasonal average daily
7 dosage or SADD. The ADD that used to calculate the SADD
8 is used from the moderate term, ADD concentration of MITC
9 times exposure days per season 120-days season. For the
10 exposure days, I used 23 days per season. Currently DPS
11 is working on exposure days for current exposure
12 assessment.
13 This slide show the ADD for adult females.
14 And for B.2, B.7, and B.8, they were from ambient
15 monitoring studies. And the first one, wherever I can, I
16 will use the Atkinson concentration as TWA. And if they
17 were not available, I will use the highest exposure --
18 highest MITC air concentrations.
19 In this case, only one applicant from each
20 site. I use the highest concentration. This study was
21 conducted in --
22 DR. GLANTZ: What was TWA again?
23 DR. THONGSINTHUSAK: Times weight of
24 average. This study was conducted in 1993. B.7 conducts
25 in 1997 and '98. As it's shown earlier, the amount of use
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BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 of Metam-Sodium for B.7 in California was about doubled to
2 the amount of Metam-Sodium use in 1993. The range of the
3 ADD from .62 to about 5 for B.2, B.7. They were very
4 similar to B.2. For the study in Lompoc, the ADD was
5 about .14 micrograms per kilogram per day.
6 Next slide, please. This table show the ADD
7 obtained from five studies. This is application site
8 studies. Contra Costa, B.3, and Kern County. And B.4
9 also in the Kern County. B.5, Madera. And B.6,
10 Bakersfield. There will be one more study that will be
11 added in the future. The industry conducted one latest
12 study. I will add that study, once the final report is
13 available.
14 There's a wide range of ADD from application
15 site study. When I say it doesn't say how far away from
16 the treated field, it's normally range from 12 to 40 yards
17 from the treated field, kilometers. You can see that the
18 farther away from the treated field, pyramid of the ADD is
19 lower than the station that is located closer, like five
20 meters. Next, please.
21 CHAIRMAN FROINES: Will you then use these
22 now for the MOE calculations?
23 DR. THONGSINTHUSAK: Next person, Andy
24 Rubin, will use these ADD for MOE calculations.
25 DR. BLANC: Why do the ranges on these ones
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BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 that you have here differ from the ranges on the last
2 slide that Pam showed us?
3 DR. THONGSINTHUSAK: That Pam show?
4 DR. BLANC: Yeah, for the same studies. For
5 example, for the Madera County, she had a maximum -- a
6 range of 1.29 to maximum of 435 parts per billion. And
7 you have a series of ranges, but none of them are as high
8 as 435 parts per billion. Whereas, your Kern County one
9 there, range -- upper range is higher than the upper
10 range.
11 DR. THONGSINTHUSAK: Pam's data have not
12 been corrected for the maximum application weights and the
13 percentage of recoveries. In my case, before I calculate
14 the ADD, I will make adjustment for maximum application
15 weight, and the percentage of recoveries.
16 DR. BLANC: So your value will always have a
17 slightly higher --
18 DR. THONGSINTHUSAK: Pardon me?
19 DR. BLANC: So your values will have a
20 slightly higher upper range?
21 DR. THONGSINTHUSAK: Yes, in most case, they
22 will be higher. Next is to calculate the seasonal average
23 daily dosage. I will use the ADD concentration from a
24 moderate-term air monitoring studies. In this case, I
25 will have more samples like for B.2.
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1 For B.2, B.7, and B.8, represent ambient air
2 monitoring data. And I calculate use ADD, multiplies
3 exposure days per 120-day season. And the range is like
4 for the B.2 from .02 to about .45. I will not go over all
5 these numbers. They are in your handouts.
6 Next, please. The SADD from the application
7 site monitoring studies, five studies all together. And
8 for the first one, B.1, 27.2 micrograms per kilogram and
9 per day. And the numbers vary according to the sampling
10 site, based on the distance from the treated field
11 kilometer.
12 Next, please. Now, there's a question about
13 a potential retention of MITC on silica gel drying tubes
14 which is placed in front of a charcoal sampling tubes,
15 not only in a sampling tray. There will be section of the
16 tubes, the front will be the silica gel drying tube, and
17 the other two absorb the excess moisture, and the other
18 two will be the charcoal sampling tube.
19 Normally, there will be two sections. The
20 first section will contain 400 milligrams of charcoal, and
21 subdivided by -- and the last part will contain about 200
22 milligrams charcoal.
23 Most studies use just charcoal tubes to
24 collect their samples. But there are two studies that use
25 the silica gel drying tubes. The first one by Wofford in
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1 1994, and the second one by Zeneca -- okay. They found
2 right by -- Wofford found at four out of ten tubes of the
3 silica gel, they can retain from zero to four percent of
4 the total MITC. And for the internal two, the retention
5 ranged from 58 to a hundred percent. So there's a
6 question there.
7 Silica gel may retain some MITC, but it
8 is -- doesn't seem to be so from the study by the
9 industry. The recovery of MITC range from 71 to 95
10 percent. So in this case, after desorption deficiency
11 correction, retention would be -- should be around ten
12 percent or less. Next, please.
13 DR. BLANC: Can you say what the
14 implications of this is?
15 DR. THONGSINTHUSAK: Pardon me?
16 DR. BLANC: And what do you believe the
17 implications of these data are?
18 DR. THONGSINTHUSAK: The implications? The
19 implications of those data is, it's likely that silica gel
20 drying tubes can retain some MITC. But I have got to have
21 some more proof for that. And most studies accept the
22 tube. Most study does not use silica gel drying tubes.
23 So, in general, I do not see any problem for that.
24 DR. BLANC: But you said that Wofford used
25 silica drying tubes.
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BARNEY, UNGERMANN & ASSOCIATES 888 326-5900
1 DR. THONGSINTHUSAK: Yes.
2 DR. BLANC: And the highest values that you
3 had were from the Wofford study.
4 DR. THONGSINTHUSAK: Yes.
5 DR. BLANC: And if the retention was high,
6 means that you couldn't remove some of the material, and
7 therefore underestimated those very high values; is that
8 right? Did I have the direction of the effect?
9 DR. THONGSINTHUSAK: Yes. If the Wofford
10 study did not include MITC in the silica gel tubes, but
11 they did. So they combine MITC from both -- both types of
12 tubes. So there's no problem for that. But that's
13 another study conducted by Zenneca. They did not analyze
14 MITC in the silica gel drying tube. But from the lab from
15 the study, they did not see that that is an important
16 issue.
17 DR. BLANC: And did you use their data in
18 any of your calculations?
19 DR. THONGSINTHUSAK: Yes, uh-huh.
20 DR. BLANC: Which calculations involved the
21 Zenneca study?
22 DR. THONGSINTHUSAK: I think B.6.
23 DR. BLANC: B.6? The Bakersfield study?
24 DR. THONGSINTHUSAK: Madera, I think.
25 Madera. Would you show the table 7.2?
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1 DR. BLANC: 7.2 or 8.2?
2 DR. THONGSINTHUSAK: B.5. Madera.
3 Actually, it's ICI. They used silica gel drying tubes,
4 but they did not analyze MITC in the tube.
5 CHAIRMAN FROINES: They didn't analyze the
6 MITC in the --
7 DR. THONGSINTHUSAK: Silica gel.
8 CHAIRMAN FROINES: So that underestimates
9 the overall approach.
10 DR. THONGSINTHUSAK: It is possible that
11 MITC concentrations were underestimate. But as I
12 mentioned before, from their study, the recovery with or
13 without silica -- with a silica gel drying tube was very
14 high. So I assume that it is not their concern, because
15 of the their findings.
16 CHAIRMAN FROINES: Well, it seems to me,
17 this is actually an issue that needs to be resolved. It's
18 not enough to say, "I think it was not important."
19 That's -- that's -- I think falls in the category of a
20 subjective comment. I think the issue is, is it important
21 on a quantitative basis?
22 DR. THONGSINTHUSAK: I agree. Thank you.
23 CHAIRMAN FROINES: So the point is, if we're
24 going to be using silica tubes to remove water, then we
25 need to know, one, is there a material being absorbed, and
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