Pronaai.de: Position Cocuaent 2/Z
Special Pesticide Review Division
Office of Pesticide Prcgrans
CT.S Environmental Protection Agency
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Fi sk/ocnef i t analysis: qualitative 4 qualitative risks c: a
;;f s 11 r ivic , vil j: o: crop uses, availability or altfrnat: vc pesticides,
exposure to n.tt r ar.- onviror.nent. Identification of r:s.< reo..n :nj
regulatory options and proposed Aqency action.
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PRCNAMIDE TECHNICAL SOPPCRT TEAM
Rlctoard Troast, Project Manager, SPRD, OPP
George Beusch, Section Bead, BED, BCB
Barry Day, Cieaist, 3 ED, EFB
Roger Gardner, Pbarnacologist, BED, TOX
Kevin Keaney, Senior Regulatory Policy Analyst, S?®D, OP3
George Keltt, Ph.O., Plant Physiologist, 3FSD. ?S3
John Leltzke, Ecologist, BED, EEB
Dorothy Patton, Attorney, OGC
Linda Zygadlo, Economist, BFSD, EA3
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Table of Contents
Page
I. Introduction. ..... . L
A. Background. ..... .1
B. Registered. CJses and Production... ...........2
C. Regulatory History . 2
1. Tolerances. 2
2. Pre-RPAR Actions......... .J
3. Post—RPAR Actions 3
II. Analysis and Assessment of Risk.. .5
A. Basis of Presumption . ...5
B. Rebuttal Arguments................... ....5
1. LacJc of Sufficient Exposure....... .5.
2. The Carcinogenesis of Pronanide. 6
3. Lack, of Carcincgen Risk. Assessment in the
RPAJt Notice..- 7
4- The Mouse in Not an Acceptable Model for
Carcinogenic Tests 7
5. Tumors Caused by Pronamide are Sot De_ Novo 8
6. Negative Mutagenicity Tests Indicate a
Non-Carcinogen. 9
C. Exposure Analysis 9
1. Dietary Exposure 10
2. Applicator Exposure 10
Q. Risk Assessxent IT
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a. Discussion of Proposed Restrictions .*...61
(i) Classify Pronamide as a Restricted
Use Pesticide and Require Applicator
. Certification .......61
(11} Require the Use of Protective Clothing
During Mixing and Application of
Pronamide................................62
(ill) Require the Torsulation of Pronami.de
(Wettable Powder) in Water Soluble Bags...63
*(lv) Cancel Hand Spray Use ...64
3. Continue Registrtaion of All Uses, Amend the
Terms and Conditions of Registration; Revise
the Tolerance on Lettuce to Lower the. Dietary
Exposure... .....65
4- Continue Registration of All Uses; Amend the
Terms and. Conditions of Registratin; Revise
the Tolerance on Lettuce to Lower the Dietary
Exposure; Require a Monitoring Report, on Resi-
dues in Milk from Pronamide Use in Alfalfa at
5 Year Intervals Coincident with Reregistration..68
Cancel All Uses............................ ..69
C. Comparison of Options...............................71
V. -Recommended Regulatory Action ......73
A. Recommendation of Options 4........... .......75
Bibliography. 81
Appendices 8 5
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I. Introduction
The Federal Insecticide,. Fungicide, and Rodenticide Act.
(FIFRA) and the related regulations requires the Environmental
Protection Agency (EPA) to review the risks and benefits of
the uses of. the pesticides which it. registers. The determination
that, pronamide poses a risk of oncogenicity (based on tuners
found in test animals) caused the Agency on May 20, 1977, to
issue a notice of rebuttable presumption against the registra-
tion and continued registration (RPAR) of pesticide products
containing pronamide.. The Agency)s analysis of the risks and
the benefits of the continued use of pronamide and the Agency's
recommendations foe regulatory alternatives are presented in
this Decision Document.
A.- Background
Pronamide is a substituted benzaaide which is
known by the trade name KZR3. Pronamide is. synthesized as a
solid* The technical chemical is packaged as a coarse powder
formulation. Pronamide products that are ready for applica—
tion are wettable powders or granulars. The structural
formula for pronamide is given belcw:
O H £#2
Vc'—N—j—C=C
-1-
CI
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B. Registered Os»g and Production
Rohm and Eaasr the only registered producer of
technical grade pronamide, . is also the largest; formulator o£
pronamide products (Kerb SOW)« Pronamide is used primarily
as an herbicide la lettuce and alfalfa.. Pronamide is also
osed for- other purposes ( i.e., controlling- weed and grass in
ornamental turf and commercial nursery planting, Table III-l)
However, the amount of pronamide used for other purposes is
significantly less than the amount used in lettuce and alfalf
Rohm and Haas exports pronamide to Canada, South Africa,
Spain,- Italy, the United Kingdom, France, and Japan.
C- Regulatory Historv
tural commodites- are listed below* These tolerances were
established, on the basis of studies presented to the
Agency from 1969 to 1975 (40 CFR 180.317).
1- Tolerances
The tolerances- set for gronaaide in raw agricul-
Alfalfa
la ppnr
Clover and Forage Legumes
Lettuce and Endive (Escarole)
S ppm
2 ppm
Blueberries- and Cane Fruit (Blackberries
Boysenberries" and Raspberries)
Kidney and Liver of beef cattle
0.05 ppm
goats, hogs-, poultry, horses and sheep
Eggs, meat, ailk, fat and neat by-products
0.2 ppm
except (kidney and liver) of cattle, goats,
hogs, horses, poultry, and sheep.
0.02 cpa
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Z- Pre-RPA3 Actions
Data, from two chronic feeding studies are
required by the Agency as part of the pesticide registration
requirements for tolerance setting- Rohm, and Haas submitted
data. in 1971 for rats (Pesticide Petition iril39) and in
T97^ for Qice (Pesticide Petition 5F1352). The rat study did
not indicate the formation of tuaors at the dosages tested.
The data presented in the souse study indicated that, at
dietary concentrations of 1,000 and 2,000 ppa, pronamide
caused hepatocarcinooas. ia aaie aice (Coberiy, 1971*) . The
Criteria and. Evaluation. Division (CED) (Potreptca, 1977) in
the Office or Pesticide Prograns (0PP) and. the Agency's
Carcinogen Assessment Group (CAG) (Albert, 1977) reviewed
these data, confirmed the conclusions froa the preliminary
review of the souse data,, and concluded that pronanide is a
carcinogen ia male mice. The Agency based the RPAR against
pesticide products containing pronacide on this data and
related reviews.
3- Post-3PA3 Actions
Two registrants (Swisher, 1977; Clark, 1977)
requested a So-day extension of the rebuttal period asserting
that the regular ^5-
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During the response period, registrants and
other interested parties had an opportunity to review the
data, upon which, the presumption was based and to submit
rebuttal information. Respondents could rebut the presunp-
tioa by showing" that the Agency's initial determination of
risk. was in. error, or that pronaai.de "will not concentrate,
persist or accrue to levels, in. man or the environment likely
to result in any significant chronic adverse effects" C^O
CFR 162.11(a)(4)], Also, registrants and other interested
persons were- offered the opportunity to submit evidence as
to whether the social*, economic., and environmental benefits
oT the use of the pesticide, outweigh the risk of its use
Cl6Z.U(a)(5)(Ui)K
This. Position Document details the Agency's
review of the risks, benefits and regulatory options which
relate- to the uses of pronaaide. Section IX presents
the Agency's conclusion that the information submitted by
respondents has not rebutted the presumption against regis-
tration, as well as its assessment of the risks associated
with the use of pronamide- Section HI contains the Agency's
analysis of the benefits of pronanide as well as the probable
costs of regulatory action to cancel or to otherwise restrict
the uses of this pesticide. A comparison of the environmental
impacts of the proposed regulatory options, weighing both
risks and benefits, is presented in Section IV, while
Section 7 presents and explains the Agency's recommended
option.
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IX. Analysis and Assessment of Risk
A. 3asls cf Presuaotlon
The Agency's presumption against the registration
of pronaaide was based upon, an 18 month souse chronic
feeding stud/ conducted by Rohm. and Haas which indicated a.
significant increase (p<0.05) in hepatocellular carcinomas
at the T ,000 and 2,000 ppta levels (?P 5F1552). There was as
observed, statistically significant dose-response relation-
ship.
B- Rebuttal Arguments
There, were 123 rebuttals received. 0nl7 twc of
these dealt with substantive rebuttal Issues and are addres-
sed in the following- section. The remainder of the rebuttals
addressed themselves to the benefits of the continued use cf
pronaalde» These comments are addressed in Section III, the
Benefits Analysis.
L» Lack of Sufficient Z.xcosure
One respondent argued that human exposure
to pronaajde or its residues is r.ot sufficient to warrant
concern. The respondent argued that the low exposure involved-
would be below the ao observable effect level (MCEL) for
oncogenic effects, and therefore no increased incidence of
tuaors- would be observed (Rarig, 1977).
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- This argument fails for two reasons- Plcst,
tumors were reported at both of the dose levels tested Ln
the Rohm and Haas study. Therefore, a NOEL was not demon-
strated Ln the mouse study cited in the RPAR, nor Ln any of
the data submitted in response to the RPAfl, and there- Ls no
basis- for arguments based on a. NOEL for pronamide.
Second, no demonstrated NOEL, has been provided
and in that case the Agency's carcinogen policy (41 FR21402,
May 2S, 1976), assess risk on the basis of no-threshold in
which case even low lwvels of exposure are viewed as a
potential cancer risk. Residues of pronamide do exist in
foods. Market basket, surveys have found residues of pronamide
ln the lettuce sold to consumers (Rarig, 1977). A recently
completed residue analysis of California head lettuce has
demonstrated pronamide residues of up to 0.09 ppra (Alford,
1978). In light of the Agency's no-threshold policy and the
absences on any NOEL data coupled with positive, this
documentation of the presence of pronamide residue in
lettuce also refutes the respondent's argument.
2. The Carcinogenesis of Pronamide
Two respondents have stated that toxicoiog ists
disagree on whether or not pronamide is actually a carcinogen
(Rarig, 1977; USDA, 1977). The results of the "Eighteen-Month
Study on the Carcinogen Potential of Kerb (RH-315; Pronamide)
in Mice" provide substantial evidence, according to the terms
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of the Agency guidelines, that- pronamide Is oncogenic, I.e.,
tumors were observed and reported at tvo feeding levels
(1,000 and 2,000'ppm), in. the male mouse. In assessing
the rebuttal, the Carcinogen Assessment Group (CAG) examined
the original histopathology slides in the .touse study. The
consultant pathologist performing the review for the CAG
(Dubin,. 1978) concurred with the original review of the
slides by Rohn and Baas. The CAG thus confirmed the original
observation of Rohm and Haas that pronamide causes an increased
incidence of tumors in mice. Further, although toxicologists
may have originally disagreed on the magnitude of the carcino-
genic potential, different interpretations do not, per se,
invalidate an affirmative interpretation, and the pathologists
in general did agree that pronamide is an ocogenic agent..
3» lack- of Carcinogen Risk Assessment in the
RPAR Notice
One commenter claimed that EPA is required to
perform a carcinogenic risk assessment before issuing the
RPAR (Rarig, 1977)..
The Interim Cancer Guidelines (41 FR 21402, May
25/ 1976) clearly state that the assessment of carcinogenic
risks is prepared after the .Rebuttable Presumption Against
Registration is issued..
4. The Mouse is Not An Acceptable Model for
Carcinogenic T«rSt3
One commenter claimed that the mouse is not an
appropriate test model since the mouse is prone to tumors
which have no bearing on human carcinogenesis (Sang, 1977;.
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data is regarded as "substantial evidence" in judging the
total weight of evidence of whether a substance is carcino-
genic (41 FR 21402, May 25# 1376).
5- Tumors Caused bv Pronamide Are Not De Novo
One respondent, attempted to rebut* the presump-
tion- by arguing* that pronamide— induced tumors do not arise <
novo, but arise secondarily to stresses placed on the hepat
tissue (Rarig, 1977).
The CAG (Albert, 1979) evaluated this argument
and found it to be ambiguous, because it was not made clear
whether the argument was referring to focal hyperplasia or
to generalized hyperplasia. The CAG therefore addressed
both conditions. If the rebuttal statement was referring to
focal hyperplasia in arguing that tunors caused by prcnamidi
do not arise de novo, the CAG stated that this argument is
illogical, since experimental evidence indicaees that hyper-
trophy and hyperplasia, are recognized characteristics in th«
neoplastic progression of liver tumors. If the rebuttal
comment was referring to generalized hyperplasia, and was
arguing that it was this condition which pronamide caused at
that the malignancy, developed secondarily to the hyperplasi.
the CAG stated that this argument is also illogical because
generalized hyperplasia and hypertrophy are not characteris•
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responses to pronamide. Thus, even if such responses occurred,
there is no further substantiating evidence which would assign
to pronamide the role of a promoting agent with a threshold
type of dose-response pattern.
Negative Mutagenicity Tests Indicate
a Non-Carcmccen
One respondent attempted to rebut the pre-
sumption by arguing that, because pronamide does not produce
mutations in the host-raediated assay (Ames Assay)(2arig, 1977)
and because of the close correlation between mutagenicity
and carcinogenicity, pronamide is not a true carcinogen.
The CAG replied (Albert, 1378) that a negative
mutagenic assay- does' not necessarily indicate that a chemical
is also not & carcinogen, because there are other* plausible
mechanism*: of carcinogenesis (e.g.r altered gene regulation).
Further* while a. strong- correlation exists between positive
results in mutation assays and in vivo mammalian bioassays,
not all known carcinogens induce mutations in the Ames test-
More specifically it is known that other chlorinated aromatic
hydrocarbons, the chemical class of which pronamide is a
member, have previously given fal:,e negative results in the
Ames test.
C- Exposure Analysis
Rohm and Haas Company and the U.S. Department of
Agriculture provided data on patterns of pror.anide use which
the Agency has used both to identify the populations exposed
to pronamide and to estimate the extent of the populations'
exposure. An average person was assumed to weigh 60 kg and
to consume 1.9 kg of feed daily.
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1. Dietary Exposure
The Agency's estimates of human dietary exposure are
based on tolerance data, residue data, and data indicating
the extent to which pronamide is used on each of the food
crops foe which it is registered (Day and Collier 1978). A
reasonable upper Lirait of the U.S. population's exposure to
pronamide in the diet was calculated, based on the average
person's dietary intake. If residue data for commodities
treated with pronamide were unavailable, tolerance data were
used. The resulting dietary exposure values are presented
in Table II-l- The annual dietary exposure from the inges-
tion of foods" treated with pronaaide is estimated to be
10.95 mg/person.
It should be noted that Table II-l assumes an equal
distribution of pronaaide treated food across the U.S. and
an average consumption of this food by individuals. In
fact, however,, it is likely that some will be exposed less
to pronaaide, depending upon the availability of treated
food in their geographic area and on their eating habits.
2. Applicator Exposure
There are three types of personnel, involved in
the application of pronamide: custom applicators (lettuce),
grower applicators (alfalfa), other applicators (homeowners,
commercial nursery personnel, and berry growers). The number
of custom applicators exposed to pronamide is estimated at
20 persons. This segment of the occupatior.ally exposed
population has the highest calculated exposure, since custom
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T7VBLE II—1. Pronanide Levels in the Diet
Product
Tblerar.ee
(mcAo)
Consumption
ka/person/day
Tbtal mg/person/day Prona-
mide intake if all food
Contained u.un Tolerance
Dcse of Prcncmide
Corrected ng/Perscn/
Cay Pronamide Intako
Based an I of Tbtal U.
Crops Treated (See
Notes Belcv)
Lettuce
2.0
0.025
.05
0.03 (.0008 - .01)-
Berries
0.05
0.0006
.00003
—
Eggs
0.02
G.055
.001
.0001
Meat
0.02
0.274
0.005
.0001
Milk, and Cairy
Products 0.02
0.567
0.011
.0001 •
Tbtal
a.06703
0.03 (0.0012-.01)
1/ Figures in parentheses reflect, actual residue data.
The following facts formed a basis for the dietary levels of corrected :ng/per son/day
pronanide intake:
a. "Cie proportion of lettuce treated with pre nam id e in the minor producing states totals
50-65% of the production (Keitt, 1978).
b. Based on inforraticn fron the registrant at a rtiniscn label reccm ended treatment to
harvest interval of 35 days a residue of 0.8p=n can be expected. An average lettuce
season is 90 days (Rarig, 1977). Surveillar.ee data on csrr.ercia.lly harvested lettuce
having a treatment to harvest interval from 77-107 days (92 day mean) ranged from
0.01 to 0.138cgn with a mean value of 0.05 for six samples'of six replicates each.
Residue studies frcm California show aean residues of <0.0S with treatment to har-
vest intervals of 63 days minimcn (Alfcrd, 1978). Residue studies frcm New Jersey
grown lettuce gave residues ranging frcm <0.01 to .15 ppn with a ninisus treatment
to harvest interval cf 60 days (Rarig, 1977). Therefore actual residue values frun
lettuce collected in the market place C2n reasonably be expected to have residue
levels ranging iron 0.05 to O.Spta instead of the 2.Cppr. tolerance. The tolerance
values are used in other residue calculations sir.ee th.s is the legally allowable
upper limit.
With the facts as stated in a. and b. the following assumptions were then xade to arrive
at the corrected tc/cerscn/day prcnanice intake.
a. Food containing pronanide residues is equally distributed throughout U.S. peculation
before ccnsinpticn.
b. Prcnznide residues in milk will be equally distributed in all dairy products whether
processed or not.
c. Alfalfa consur.ed iv neat and dairy oews throughout U.S.A. all contsins a weigr.ted aver:
aaount of prcr-cnice. g g
d. Cut of a total cc 75.4 X10 tons of alfalfa grown in U.S., 0.42 X 10 tons (0.554! is
treated with prcnaxide.
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application Is the prevalent method of using pronamide in
lettuce fields and more than 40% of the pronamide used is
used on this crop. The individual grower of alfalfa is
normally the applicator, so his exposure is similar to that
of the custom applicator. The number of grower applicators
la estimated to be 3800. The alfalfa, grower uses pronamide
only once a year, unlike the custom applicator who uses it
several times yearly. Therefore, the total yearly exposure
of individual grower applicators to pronamide in alfalfa
operations would be less than the total yearly exposure
of individual custom applicators In lettuce operations.
Applicators who use pronamide for other purposes use it only
once a year and usa the wettable powder formulation or a
pronamide/fertilizer product (turf applicators only)_
The exposure of these-ap'STicat'ors should not exceed the
exposure which alfalfa growers receive, and may be less
depending on the formulation they use and the size of the
area on which they use it.
The annual unit, exposure to applicators from
pronamide is based on three studies. One of the studies
used to estimate exposure was the model of Wolfe (H.R»
Wolfe, 1967 and H.R. Wolfe, 1975). The Wolfe model con-
siders exposure resulting from bag opening, mixing, ar.d
applying a chemical (parathion). The two other studies
(Krermenski, 1978; Jegier, 1964) consider exposure resulting
from bag opening and mixing using pronamide. The values
calculated from these models are reflected in Table ZZ-2
(lettuce) and Table II-3 (alfalfa).
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Table I1-2. Oinulative Occupational Exposure to Custom Applicators - Lettuce
Santa Maria
Valley
Salinas
Valley
Imperial
Valley
Other Areas
in California
Arizona
Total Acres
13.200
60,280
26,500
14,550
9,250
Itotal Applicators (estimate)
1.75
8
3.5
1.9
1.2
•natal ai applied per acre
0.9
0.5
1.1.
0.5
1.1
Ban openings per applicator
4,525
2512
5,552
2,552
5,652
Annual dermal exposure (front
bag openings) per applicator
per kq body v/t per year
W*Mf525
996
Rll»»"317
2512
552
176
5552
1221
389
2552
561
179
5652
1243
395
Annual dermal exposure (during
spray treatment) per applicator
per kq body wt per year*
W
rut
5 1 5
I
0.5 | 0.5
5
0.5
5
0.5
5
0.5
Annual inhalation exposure
(fron bag openings) per
applicator per kg body wt
pei year
w
j
Rll
9.0
22.6 j
1.8 1
5.0
12.5
1.0
11.0
27.5
2.2
5.0
12.5
1.0
11.0
27.5
2.2
"total Exposure from Dag
Opening
W 4534.0
J 1018.6
Fll 318. Q
2517.0
564.5
177.0
5563.0
1248.5
391.2
2557.0
573.5
180.0
5663.0
1270.5
397.2
Annual iriialation exposure
(during spray treatment) per
»ppl lcator per kg body wt per
year4
w
RJI
.03
.01
.03
.01
~
.03
.01
.03
.01
.03
.01
"totals Exposure from Application
W
RJI
5.03
0.51
5.03
0.51
5.03
0.51
5.03
0.51
5.03
0.51
~ftr.ed on 50 treatment days per year. I
•MJ >1 fe
•*vic
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Table II-3. emulative Occupational Exposure to growers - Alfalfa
Total Acres
94,500
Average Acres of Alfalfa Bay Grow Pec Farm
49
Tatal Number of Far=ts Using Prcnaiude
1928
Total Bag Cpemnga per year
49-
Tbtal Nunfcer of Applicators
2856
Annual Denral Exposure frcm 3ag Openings
w*
49.0
rogAg
body
weicnt
J*
* 10.8
mgAg
body
weight
** 3.4
mgAg
body
weicht
Annual Inhalation Exposure fran Bag Openings
W
0.1
mgAg
body
weight
J
0.25
mgAg
body
weicnt
PS
0.02
ragAg
body
weight
Total Leader Exposure
w
49.1
nsgAg
bocy
weight
'
J
11.1
neAg
body
vplent
HH
3.4
rag/Xg
body
weighs.
Annual Dermal Exposure from Application
W
0.1
rogAg
body
we icht
FH
0.01
mgAg
body
weight
Annual Inhalation Exposure frcra Application
W
0.0005 mgAg
body
weight
RB
0.0001 :agAg
body
weight.
Total Applicator
W
0.1
Pff
0.01
Tbtal
49.2 -
3.40mgAg bocy weicftt
•Vtolfe
**Jegier
#**Rchm and Baas
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Bach of the studies used in determining exposure
is not directly applicable to the field use of pronamide or
is flawed. For exampLe the Wolfe study used a 1% product
while the actual use of pronamide involves using a 50%
product* An extrapolation from a model using a It TEPP
product to draw conclusions regarding a 50% product may
introduce a substantial overestimation. These overesti-
mations would occur since such an extrapolation assumes a
linear relationship which may not exist. The Rohm and Haas
study is weak since only one replicate was made of the work
and since it underestimated exposure by measuring glove area
instead of hand area.. Therefore, while the complete applica-
bility of all of the studies is weak to some extentf the
Agency considers the Jegier work to represent a reasonable
average exposure value. For the purposes of this analysis
the values based on Wolfe will be taken as the upper limits
of exposure and those from the Rohm and Haas study will be
taken as the lower limits of exposure. The range of values
calculated from these models reveal potential yearly exposure
for custom applicators (lettuce) and range from 4,159 mg/kg
using Wolfe's model, to 915 mg/kg using Jegier's model, to
291 mg/kg using the Rohm and Haas data. For alfalfa growers,
the potential yearly exposure is 49 rag/kg using Wolfe, 11.2
mg/kg using Jeiger, and 3.4 mg/kg using Rohm and Haas' data.
These values are due to dietary and occupational exposure to
pronamide. The oral exposure (0.13 mc/kg) is an insignificant
addition to these values.
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The exposure to pronamide of honeowner/turf
maintenance specialists through a. pronamide fertilizer
product is SO times less than the comparable exposure of
alfalfa growers. In addition, a pronamide/fectilizer
conpoand would be a granular product, not a wettable powder,
thus minimising inhalation exposure. Derrral exposure would
be similarly minimized by the granular formulation {Day and
Collier, 1978). Consequently, any exposure to this segment
ct the population is smaller than the exposure to alfalfa
applicators.
The exposure from hand spraying, which could be
common in certain uses (berries and nursery stock), is more
difficult to estimate because the clothing, equipment, time
exposed, application.rate, and other factors are undetermined
variables. However, again using the data developed from
Wolfe.(Wolfa. 1567)/ a calculated estimate of the total
exposure from this type of application is 0.9 mg/kg/hr.
Assuming that growers would switch to mechanical spraying in
order to cover larger areas, their total exposure should not
exceed that calculated for alfalfa growers. Thus, applicators
who use pronanide for other purposes would receive a
maximum annual exposure to pronamide of 49 rag/kg, 11.2
39or 3.4 mg/kg (depending on the model used to calcu-
late the exposure).
-16-
-------
D. kisk Assessment
The cancer risk assessment for pronamide is based
on the principles and procedures outlined in the EPA Interim
Cancer Guidelines (41 PR 21402, May 25, 1976). These guidelines
specify that a substance will be considered a "presumptive
cancer risk when it causes a statistically significant excess
incidence of. benign or malignant tumors in humans or animals" ,
that current, and anticipated exposure levels are appropriate
considerations, and that cancer risk estimates may be derived
from a variety of risk, extrapolation nodels.
The CAG reviewed the oncogenicity data, concluded
that pronamide did produce statistically significant numbers
of hepatocellular tumors in sale mice (Albert, 1977) , and used,
this data in the one-hit model to estimate the cancer risk
(Albert,. 1978). The one-hit slope parameter estimate based
on each exposure level separately is derived from the following
equation:
B - In I CL - PQ) — (1 - Px) 1
for the mouse data, substituting- the appropriate responses
gives:
B • In [ (1 - 7/96) — (1- 21/96) i/1000 - 1.711 X 10~4 ~
for the low dose and
1/ a =» slope.
In » natural locarithia.
Po * nice with liver tumors in control.
Fx a mice with liver tumors in low dose (l,00Cppra).
mice with liver tumors in high dose (2,OCCppm).
17'
-------
for the high do3e. These estimates were well within the
normal biological variability of each other and thus provide
support for the cnoice of the linear one-hit model.
The CAG estimate/ that the lifetime probablity of
a cancer due to ingestion of pronamide is provided by the
following- equation z
7 » (1.711 X10~4)X,
where X is the pom in the diet. Table II-4 gives the
Individual risks associated with ingestion of pronamide by
commodity. The sua. of the risks front dietary exposure will
range from 3.01 x 10 ^, assuming residues in lettuce of 2.0
ppm, to 1.01 x 10~*7 ,vhen residues in lettuce are 0.05
ppm.
Por- applicator exposure the CAG estimates an equivalent
dietary exposure. An example calculation of dietary equiva-
lence is illustrated below for exposure due to bag openings.
60 X 3692 X 40 » lifetime dose mq ..
365 X 70 X 1.94 lifetime food intake » 178.7 ripra —'
60 =» 60 kg*, person
3692 » annual bag openings at 1 mg/kg exposure
40 "¦ 40 yr. working history
365 » days/year
70 ¦ years average lifespan
1.94 3 daily food intake (kg)
-18-
-------
Table 11-4-
Risk and Expected Cancers Associated. vith Che Ingestion of Prooaoide
Life c use
Corrected
Aver.
are
Lifetime Probabilit/ o£
Expected Nur
ag/Pcrsou/
PP«a :
La
Cancer Due to
Cancers per
Produce
Dar
diet
Ingesting ?rcca=u.de
Tear
Lettuce
.0008
4.29
X
uf^
7.42 xio~a
0.23
.0L
6.86
X
K>
1
o
•-<
1.18 X 10"*
3.66
.03
1.72
X
N
1
O
2.98 X 10^
9.24
EMS
.0001
5-20
X
o
1
iA
8.90 X L0"9
0.03
Meat:
.0001
3.20
X
io"5
8.90 X 10~9
0.03
Milk
.0001
5.20
X
10"5
8.90 X 10"9
0.03
8«rr-i.®s*
Hac Significant
Total When. Xe5idue
•
ia Letruce is
.OS ppe
1.01 X io"7
0.3Z
.8 ppm
1.2L X i0~*
3.75
2.0 ppm.
• 3.0L X 10~* .
9.33
-19-
-------
Exposure estimates frcm all the studies (Wolfe,
Jegler, and Rohm and Haas) were inserted into the dietary
equivalence equation and an exposure value concentration in
pom was determined. This exposure value was then inserted
into the equation to obtain the risk assessment. The
assessment of the risk for applicators, Table II-5, reports
a. risk calculation only for the mixing operation based on
the exposure estimates from each of the three models. This
calculation is the highest, calculated exposure value and
consequently represents the highest risk. All other risk
calculations are based on exposure calculations which use
Wolfe's model, since the exposure for application operations
is less by several. orders of magnitude than that for the
nixing operation.
-20-
-------
T-»M* ll-l
fUak «n4 Cancer Potential juaoclatad with lha Application of ftonaaldc to AHalfa «n4 Uttuoa .
fiunrc* ft Kit# E»pojur< Uwli R>ulbll|ty Expected
of of -of Corner Dim to Concert
bpoourc Cipoaor# iwi/Vi/yr tlfttlme avcrao* tn» Pro«i.»Ma Per Year
y
JkW'lfa
W
Rl##*
W
!«•••
w
»!•••
R-vj qponlirj
Dif W»j
Hit lio
(\«.r«t |ona
Der*ul
Inflation
4»-0
0.1
io.a
0.25
).4 .
0.02
2.J7
*
10-J
0.52
0.01
0.14
0.0009
4.0«
1.29
*
*
,0-7
10 '
ft.69 x 10~?
1.7 x 10 *
2.7) x 10'?
1.54 x »0
Sf-f «y 1 orj
lorta
Dcraul
inhalatla)
0.1
0.0005
—
4.14
2.42
x 10"?
x*10~5
1.21
~ u
s
>
i°:J
10 '
1Vjt*l
4».2
11.5
J 4
2. J#
M
4.0»
X
10-<
ft.9) S 10"5
2.14 x lo"*
Ul tuo*
W
JM
»•••
Bd<] (Ijxnli)]
Due Ir*)
Hit 1 <«9
(^*.<•1 Ions
Derml
lr\Julat|on
)(92
2
•12
1.65
25S
l.S
171.7
.1
M.l .
? x 10 '
12. S .
\ x io~«
).04
1.71
X
X
i°:l
10 *
4.7) % lo'J
).4J X 10"'
2.14 x \0~_
4.84 x 10
aylnrj
C\-<.i*t l1 1-
co Applicator cspoauro levels for tha minor vol its • uses should rot uctdi Applicator erjxxvjca levels for alfalfa, therefor* th* llfctLM
pooaltlllty of fancer fiqn thcaa alnor vol ma uses should ba oapparabl* to the llfotlae possibility of conocr toe alfalfa.
-------
Ill» Benefits Analysis
A* Introduction
This section of the position document was derived
from.the Preliminary Benefit Analysis of Pronamide which was
prepared by the Benefits and Field Studies Division of EPA.
Although only the major uses ot Pronamide on lettuce and.
alfalfa are discussed in this section, the underlying
report, covered all of the uses reported in Table III-l.
The preliminary analysis presents information
on the amount of. the pesticide used, evaluations of its
efficacy for weed control, articulations of pest-control
strategies with and without, pronamide, and on the identifi-
cation of- the economic impacts attending each strategy - Data
foe the Preliminary Benefit Analysis of Pronamide was
developed- in part, using information supplied by Rohm and
Haas, U.S. Department, of Agriculture (USDA), and other
interested parties.
B» Lettuce
1. Biology of Weed Control
Pronamide is applied annually to 123,900
acres of. lettuce in California and Arizona as a basic
component of a weed-control strategy which includes the
use of both chemical and non-chemical techniques.
Pronamide aay be applied alone or in combination with
other chemicals such as benefin. In either event, the
use of herbicides is always supplemented with hand and
mechanical cultivations.
—22—
-------
Table Ill-l .
Pronamlde l)3e Patterns-'
Site
U.S. Acres
Grown
Acres Treated
with Pronamlde
1 Acres Treated
with Pronamlde
Application
Rate per
Treated Acre
Aplications
Per Year
Alfalfa \\&j^
27,000,000
94,000
0,35%
1.0 lbA
1
Alfalfa £eed
300,000
21,000
5.5%
1.25 lb/A
1
Clover Scod
370,000
6,000
%
2.2%
1.25 lb/A
1
I3900^/
>3900
1.0 lb/A
1
Ilcrry Crops
9720
5250
54.0*
1.5 lb/A
1
1. EPA Benefits Assessment Report
2. Includes other legumes for foragq
3. lettuce assessment Is California and Arizona only. These 2 states account for &"l\ of the U.S. lettuce
production ;
4. Hiero may be 3 lettuce crops per year on the sane acreage with pronamlde applied once per crop season
5. Octal l>ennuda grass turf acreage not available '
6. 'ibtal SuQarheet seed acreage rvot available
-------
The weed-control strategies currently used
by lettuce growers in Arizona and California vary by
region and season due to such factors as weed spectra
(with both seasonal and geographical variation) , soil
types, crop rotations, temperature, and rainfall. Five-
lettuce producing regions —— Iraperial/Blythe, Salinas,
Santa Maria, other California areas, and Arizona —•
use weed-control strategies which include the applica-
tion of pronamide. Table III-2 reports the use of pronamide
and benefin, the most widely used herbicides on lettuce in
California and Arizona, in 1977 _ Pronamide is used to treat
approximately 55 percent of the acreage on which lettuce is
produced in these states* In the coastal growing areas of
California, Salinas, Santa Maria, and Oxnard, 95 to 100 per
cent of the acreage is treated with pronamide alone or in
sequential treatments with either benefin, propham, or
CDEC. In Arizona, pronaaide, benefin, bensulide, and/or
propham are used in combination with hand and mechani-
cal cultivations to control weeds in lettuce. It is
estimated that most of the winter-planted, spring-harvested
lettuce in Arizona is treated with pronaaide.
Pronamide is used as a basic ccmponent of
weed-control strategies in lettuce due to its range of weed
control. Pronamide controls a relatively broad spectrum of
weeds, some of which no other registered herbicides will
-24-
-------
•able III-2
Estimated Herbicidal Uses in California And Arizona Lettuce Acreage,-' 1977
CALIFORNIA
Herbicides
Salinas ^
Valley
Santa Maria
Valley b/
Imperial
Blythe cf
Other^
California
Arizona d/
Tbtal
Pronamide
60,200
13,200
26f500
14,550^
9,250
105f70l
Pr onamide/
Dencfin
18,120
Nat Used
Nat Used
Itot Available
Not Available
18,120
Denefin fc
Other Denefin
Cuihinations
Itot Used
«
Not Used
26f500
Nat Available
Nat Available
Nat At
Estimated I-ettuce
Acreage
60,400
13,200
53,000
29,100
38,050
193,751
-------
control., specifically, those in the. mustard, family (shephard's.
purse/ wild mustardr and London rocket). Table III—3
reports the control spectra achieved by pronamide and its
alternatives as well as their relative: ranking- in efficacy ~
The methods of applying pronamide can vary. Growers
can either apply it to the- surface of the soil after they
plant the lettuce^ seed, (but before the emergence of weeds)
and incorporate it into the soil by irrigating with sprinklers
(the most common practice), otr they can. incorporate it. into-
the soil before planting the lettuce seed and activate it by
irrigating. Pronamide's methods of application allow use
by lettuce growers in areas where, during- the rainy months
o£ the winter planting season, they cannot use chemicals
which require incorporation into the soil. If growers, till
the heavy-textured soil of these areas- when it is wet, the
soil form? a hardpan several inches beneath the surface
which the lettuce roots cannot readily penetrate„
Another advantage of the use of: pronamide
is. that it has a short residual life which allows growers to
grow most of the crops that are normally rotated with
lettuce immediately after harvest. Residues of benefirr (an
alternative to pronamide which is currently used in some
areas and which, growers would be likely to include in any
strategy of chemical weed-control to replace pronamide)
are more persistent. The use of benefin would limit, the
crops- that growers could plant following lettuce in rotation
in all of the lettuce—growing areas~
—26—
-------
Table 111-3
Comparative Efficacy of Alternative Herbicides in Lettuce
Herbicides
Benefin &
Weeds
Pronamldo
Benefin
Propham
Bensulidc
CD DC
Propham
Barnyardgrass
P
C
N
C
C
C
BurnIno nettle
C
P
C
N
c
C
Canary graos
C
P
C
C
N
C
Cannon groundsel
N
N
N
N
N
N
Cral*jrass
C
C
N
C
c
C
Cupgraas
P
C
N
C
c
C
Fiddlcneck
C
C
N
P
p
C
Gnoaefoot
C
C
H
P
?
C
GrourJdierry
P
N
N
N
H
N
Hairy nightshade
C
N
C
N
N
C
llcnbit
P
H
C
N
N
C
KnoUAiod
P
C
P
H
P
C
l.anJ quarter a
c
C
N
P
P
C
london rocket
c
N
N
N
N
N
Hdl Vd
c
N
H
H
P
N
Mustard
C
N
N
H
N
N
Pigv.ced
p
C
N
C
C
C
Prickly lettuce
N
N
N
N
P
N
Puralane
C
C
N
C
C
C
fiht^ierdspurse
C
N
N
N
H
P
Annuo 1 yellow sweetclover
P
N
N
H
N
N
Gowtliibtle
N
N
N
N
P
N
Volunteer cereals
•
(barley, vtieat, etc.)
c
N
C
N
N
C
•total C
J3
9
5
6
6
14
P
7
1 12
1
7
7
1
N
3
17
10
10
8
1/ I
C-Control| p-partial Control; Jf-No Control j
fjdtirro: llnlvcrnltv nf fV»l i fnrnla. rvtvl«» nlulpinn r\t ion
-------
A substantial economic benefit from pronamide use
depends, on the weather conditions in several of the. lettuce-
growing regions- During- opti.uaL weather conditions, the
alternative weed-control strategies are sufficiently effi-
cacious to maintain yields at a level equal to those achieved
through the use of pronamide. However, in the Salinas and
Santa Maria Valleysr winter rainfall can delay the optimal
timing of the mechanical and hand cultivation which is
required in. the absence of pronamide. The delay in cultiva-
tion could increase weed competition and ultimately reduce
lettuce yields. No information was available to define
9
optimal, normal, or adverse weather conditions as they
affect use. of herbicides in lettuce production^ For
example,., the information generated in the analysis which
supports, this document does not enable an articulation of
the number of days- of rainfall which would be considered
either optimal or adverse and, therefore, no estimate
can be made of the frequency or intensity of the adverse
impacts on yield- The only information which was available
in this regard were the opinions of knowledgeable individuals
in California who estimated that a prohibition of the use. of
pronamide on lettuce would result in a 20 percent decline in
yield on 25 percent of the acreage (18,400) in the Salinas
i
and Santa Maria Valleys- Their opinions were that this loss
would: occur under- normal, weather conditions; however, no
attempt was made to define the mean and the variance around
the norm..
-28-
-------
2. Economics
a. Onderlyina Assumptions
The analyses which were performed to determine
the economic benefits were subject, to data limitations which
required several critical assumptions. The following are the
major limitations and the resulting assumptions:
(1) Published data or experimental results
that would identify possible changes in yield, given the
cancellation of pronamide, were unavailable. Therefore/
based on the knowledge of weed specialists-^/ who are
familiar with the practices used for growing lettuce
in California and Arizona, the Agency assumed that current
levels in yield would be maintained, except in the Salinas
and Santa Maria Valleys where 18,400 acres would experience
a 20 percent loss in yield due to inclement weather (as
discussed in the Biology Section). Although there are no
firm data or experimental findings to support the latter
effect, the Agency used this assumption to reflect the
consequences of its potential policies under differing
agronomic situations.
Salinas Valley H- Agax-aLLar., 'J. of CalifcrTua Entersicn Servica
Coastal Region A» Large, U. of Caliicmia Exterjicr. Service
Lroenal/Blythe 0. Cudney, 0. of California Extension Servio
Arizona Hzmiltcn, 0. of Arizona Extension Service
-------
(2) Published data specifying alternative
weed-control strategies by each region was unavailable.
Therefore, based on the knowledge of weed specialists (op.
cit.), the Agency assuxaed that growers would use a bene fin/
propham treatment, foe weed control in combination with
additionaL hand labor and mechanical cultivation en. all
acreage in the Imperial-Blythe area, in Arizona, and in the.
region identified as "other California." If this assumption
is inaccurate and growers cannot chemically control weeds on
a significant portion, of this acreage, their labor and
production costs could increase substantially»
~
(3) Because of. a general lack of data about
lettuce production and about the use of pronaaide in the
*other California" and Arizona regions the Agency assumed
that production techniques in these regions would be similar
to those reported for Salinas and Santa Maria for "other
California" and Imperial-Blythe "f or Arizona.
(4) Because oiL the imprecise data which
the Agency used to determine the effects on yields and
prices the Agency limited the economic analysis in this
position document to direct effects on growers. In most
instances, the Agency examines a full range of the potential
econoraic effects of a restrictive pesticide policy. In this
instance, evaluations of changes in supply and in price
would have suggested substantially more credibility in the
underlying data than actually existed. This type of analysis
—30—
-------
can be refined if and when more precise data become availabl
The Agency did not consider the seasonal effects which could
modify its economic conclusions, because supporting data
were not available.
b. Costs of weed-Control Strategies
The current strategies of weed control
combine the use of pronaraide (v/hich is sometimes applied in
sequential treatments with benefin), hand labor, and machine
cultivations. If the registration for the use of pronamide
on lettuce- were cancelled, growers could adopt one of
three alternative strategies. The chosen strategy would
~
be dependent on location, climatic/environmental factors,
and crop rotations.
The costs of weed-control strategies vary
by region in response to cultural practices, climatic/
environmental conditions, and weed spectrum, if the regis-
tration for the use of prcnamide were cancelled and new
weed-control strategies adopted, the costs of weed control
would increase. Table III-4 identifies the additional costs
of weed control which would be incurred by growers if the
Agency cancelled the registration for the use of pronamide
on lettuce. When alternative chemical controls can be used
in combination with increased levels of hand and mechanical
cultivation, costs of weed control would increase by aocroxi
mately $45 to $55 per acre representing a 2.4 to 3.0 percent
increase in the costs of production ($1,818 average produc-
tion cost per acre).
-------
I^ble III—4
Comparison of Mlnlmurt Costs Per Acre of Pronamlde and Alternative
Weed Oonttol Measured
California
Herbicides Salinas Santa Maria Imperial, Other Arl7ona
Valley Valley Dlythe California
Pronamlde
rronoinlde Cost^ 8.50 15.30 10.70 8.50 10.70
Application Co3t 6.05 6.05 6.05 6.05 6.05
Total Cost TT55 21.35 2*775 14.55 21.75
(ler.s base labor value)
Bcnef in-Propham.
Uenofln Cost^, 2AlP 5.18 6.11 2.44V 5.11
Pcopliam Costs^ 11.40 —7/ | 11.40 U*40*/ 11-/,°
Soil Incorporation costs 4.60 11.50 ! 11.50 4.60-^ 11.50
Additional hand labor k; 40.00 40.00 I -40.00 40.00 40.00
Additional cultivotIons-' 10.00 10.00 ( 5.00 10.00 5.00
Total additional costs 68.44 66.68 j 74.01 68.44 74.01
Differential 53.89 45.33 49.26 53.89 49.26
(ler.s base labor value) '
5/ *
Mon-Oicmlcal-'
Additional Hand labor 150.00 150.00
Additional cultivations-' 15.00 15.00
TOtal additional costs 165.00 165.00
Differential 150.45 143.65
(less base labor value)
T7 Grower costs for pronamlde $17.00 per lb. a.l. (USDA/state Assessment Teem, 1977).
2/ Grower costs for bonefln $11.10 per gallon,(1.5 lb. a.l. per gallon (USDVState Assessment Team, 1977).
3/ Grower costs for propham $9.50 per gallon, 2 lb. a.l. per gallon (USrvy/State Assessment Team, 1977).
~K/ Grower costs of $5.00 per acre for each additional cultivation.
5/ Non-chemical weed control programs would only bo used In Salinas and Santa Maria Valleys where weather,
noil conditions and rotations preclude the use of benefln.
6/ Sequential treatments of ber.efln and pronamlde are currently Used on 30 percent of the acreage. If pronamlde
Is cancelled, benefln will be used on 50 percent of the acreage. These cost figures Indicate the average
additional costs per acre of benefln application and soli incorporation charges.
7/ Hio Santa Maria Valley Weed spectrum does not Include weeds controlled by proph/tr (Clsncy, 1977).
8/ This table reflects enly the oddltlonul hand lnl»r and cultivation cor.to necessary to bring weed control
by alternate strateglen up to the le>/el of pronamlde. There is a base labor Value which would be Identical
-------
The preferred alternative strategies would
combine chemical and non-chemical weed-controls such as
a combination of benefin/prophan (propham would not be
used in tbe Santa Maria Valley due to the weed spectrum),
hand labor, and mechanical cultivation. The use of benefin/
propham. (or benefin alone) would require an increased
number of hand and mechanical cultivations compared to the
number of. such cultivations require with use of pronaziide.
Without pronamide, the only effective
weed-control strategy that could be used on about half of
the acreage in the Salinas and on seventy percent of
the Santa Maria, acreage would be exclusively non-chemical*
On this acreage, benefin/propham could not be incorporated
into the soil due to rain and heavy-textured soil, or
would not be applied due.to the longer residual life of
benefin. Oader a. strategy of non-chemical weed control/
large amounts of hand labor and numerous machine cultivations
are required. Although herbicide costs would be eliminated
on this acreage, additional hand and mechanical cultivation
would increase the costs cf weed-control by approximately $145
to $150 per acre, resulting in a 7.9 to 8.2 percent ir.craase
in the costs of production.
-------
foe the use of pronamide on lettuce/ the growers would be
affected by the increased costs of controlling weeds on all
lettuce acreage which they currently treat with pronamide,
and by a potential for decreased yields cn 25* of the
Santa Maria and Salinas Valley acreage. When growers
could practice alternative chemical-weed-control strategies
and maintain, yields, their losses in net revenue would be
approximately $50 to $55 per harvested-acre as indicated in
Table III-5.
In. the Salinas and Santa Maria Valleys, the
cancellation of the registration of pronamide could result
in the adoption o£ non-chenical strategies of weed, control-
In that event, and if yields were maintained, net revenues
would be reduced from $567 to $417 and fron $567 to $423 pe
harvested acre, respectively, as Indicated in Table III-6.
As indicated earlier, however, the cancellation of the
registration for pronamide could result in reductions in
yield in these areas. These losses in yield could occur
because o_i the combination of rainy weather and heavy
textured soils which cculd prevent growers from cultivating
fields at the optimal tiae, thus forcing seedling lettuce t
compete with weeds. Onder conditions such as these, the
cancellation of the registration for pronamide'3 use could
result in reductions in net revenue for the grcwer of from
$567 to $159 and $567 to $165 per harvested acre Li the
Salinas Santa Maria Valleys respectively.
-------
T^bu iii-a
Het ncvciut Changes per Ictm par lurvcst Associated with tho (Uncoilalien
Pf frottaolda to California tn) XtIkm Lcltuco Ctowcci itfln] AltcrtMtlvo dxulcal flonlroli
"Vlfli ProcuaRo
bnctllitlon of Pron.j»l3o
will) iltcrmttvi liiwiuli
Ntk f^uenuc U>itu
UalnQ Xltimitlv<
CIiu«Icj13
Ion
QcoatrS
(VovtncM
production
Costs
Met
IWtfcnu*
Cross
Fevcnuo
rrnVictlon
Cod to
Hjt
ncvovt*
• — dolliri per
Acrs — -
- —631 Uru per icti -
4>n«ri per tors - -
C«l|(orolt
hllrui (100 cwt)
2400
Ml
2400
1381
SI)
if
#
ftuilt K>rl» ()00 cvt)
2400
H1J
*1 .
2404
1007
Iap*rlt1/Bl yth*
evi)
1112
1004
M
1*72
10S1
11
41
1
aiicr
m
Mk
IA
HA
m
u
U»
1
lirlon (211 cvt)
1904
1004
100
190|
18S1
SI
4»
1/ Aaamca Uiluc* prlc* oC fO.OO p
-------
Thblo IIl-C
Mat Itovenue Otwvjcs per Aero OMcltttd with U»« cancellation of
ftonaidt to tfllnu mi («ntt Kirti valley Uttuco Qrowcra Using Ibn-dmlcal
Vked Oontrol*
tilth frontolde
i Cancellation of ficnnldo
uilo) i' VY-dicalcal H»1
Alternative*
Qroso
fevenufr-'
Production
(bote
Kot
Kcv
cnuc^
Crc£i
|fcv:me
Product len
QuU
Net Rcve/we
Usico boa
using ikMt-tfitalcil
control
IV>t *
Revenue*
CallforpU
'ftalina*
yield 100 cvl
yield 310 cwtl/
fante Kule
ylald )06 cwt
ylald 340 cvt^
3400
3400
!•)}
)•))
-llara por fare
U)
U1
3400
1920
3400
1920
Mil
1741
1977
1155
4*7
W
W
U5
ISO
iOI
144
403
)/ Qjitcn hirvut rate* are charged on a piece ^uti at the rate of $1.13 per carton
A 30 (Krcint yield reiictloA would foduoe the harwcotlng portion ot proJuctlon
ooota aft*o«leate!y 20 percent (tan $1,110 to (800 per Acre.
3/ Juj«iir>a» price of (6.00 per cut.
fourotn T«1>U 17. Preliminary MxiaiAt of pcneflte of Proiunlde* tPA, 1977,
-------
growers in California and Arizona, if the Agency were to
cancel the registration for prcnanide's use, and assuming
the yield effect, would be $15.1 million of. which approxi-
mately $10.34 million would be in additional production
costs and $4.2 million in net. revenue loss (production
losses minus reduced harvest cost). [See Table III-7] .
The areas most affected by a possible
cancellation of pronaaide's registration are the Salinas
and Santa Maria Valleys which currently produce 41 percent
of U.S. lettuce. It. is estimated that the ccst~of lettuce
production could increase by $6.2 million and $1.6 million
in Salinas and Santa Maria, respectively. . Furthermore,
average annual yields could decline by approximately S
percent, creatingaloss _in net revenue of $4.8 million in
the Salinas and Santa Maria areas (ignoring the subsequent
effects of. price adjustments in the marketplace).
The costs to the growers in the Salinas
Valley who transplant, lettuce seedlings directly into the
fields were not. quantifiable. If. pronaside were cancelled,
these growers could utilise alternate herbicides or revert
to the technique of seeding lettuce directly into the
fields. However, there was no data presented to develop the
quantitative icpact3 which could occur. For purposes of
this document, total impacts, whether from direct seeding of
lettuce or frca transplant lettuce, are included together.
-------
nbli 111-7
HOfrtqtti Uoer tapactr-'
California
krof* UjIrrj pronaalda
>-crc«)e tulng Qiaalcal
Mltrnatlvto
Mlltlorul (beta Par f£t<
TOfJO.
letcage UiIng |&v-Qi«»Icj|
1^11 cifiat Ivta
Jinlilorti Cb»ta far Act*
JWUJ.
Tit*l AJJltlon»l Costa of
Ixituca Itc.lactIon
Ixrca Capcrluwlni) V1 •)<3 Lnaa
(tin lo UcIIkc Corvlltlonu-'j .
Ciivjg kvuma toot Par^Acr*-^
lljivtyk It-Joci lonr'
fUvinoe Inow |fro6« Lvcma loae-
luivtat (tut (liluct loo) Tcr Acre
|u.utnua loot 1 Liiult Ir»j frai yield
d.clIna
T^t»l ooul of rruu^ldo
CiliCtlUlICA
Stllru
Valley
60,(00
10,200
$51.09
$1,627,478
10,200
$150.45
$4,541,590
IM7i,oc»
15.100
$400
1220
1260
$1,926,000
110,097,06#
Cunta H>(l*
Valley
11.200
1J0Q
145.11
1149,509
9,900
$141.(5
fl,422,115
(1,571,124
3,100
$<80
$220
$260
$•51,000
$2,429,724
Imperial
Olytho
26,500
26.50Q
$49.26
$1,105,190
$1,105,190
cibtr
CtlUoaili
)4,550
14.550
$51. C9
$714,100
$714,100
lirluni
9,250
9,250
$49.26
f455,655
tot*}
121,900
01,100
$51.51
$4,122,212
40,100
$118.77
$5,965,725
|455,655 $10,287,91?
U.4C0
$<00
$220
$1,105,190
$784,10Q
{455,655
$260
$4,784,000
$15,071,917
1/ IViaul C4\ tutlaMol 197J acreage, 1977 cruio, atd 1977 prlcti m) usuilnj an tdijutta labor aupply.
5/ Asotin j 251 of itio Btllnu cid Santa Kir la Valley will upcrlcnco a 204 yield decline rcaultliv) I ton
dcltya In timing of cultivations and bird li^cr doe Lo rainy winter clunate UiwiilltA, 1977b).
1/ Aanumu ujfftnt yield of 10,000 lUo. per tac
-------
C. Alfalfa
1. Biology of Weed Control
a» Alfalfa Hay
Alfalfa, is a perennial legume grown for forage
throughout the United States. In 1976 , it was reported
that 27,000,000 acres of alfalfa hay were grown* 94,500 of
these acres, or 0.35%, were treated with pronamide. The
problem-weed spectrum encountered by growers and controlled
effectively by pronamide is found only in the Northeast,
the Midwest, and in the irrigated West. Of the total acres
of alfalfa in these areas (9,000,000 acres in the Northeast
and upper Midwest and 4,500,000 acras in the irrigated West),
pronamide is applied to 67,500 acres and 27,000 acres,
respectively. These acreages represent. 0.6% of the total
alfalfa-acreage, on which pronamide is efficacious. Eowever, .
—pronamide is a relatively new tool for weed-control in
alfalfa, and growers are still in the process of accepting it
(Ryan, 1977; USDA, 1977).
Foe the irrigated alfalfa grown in the West,
the major weed pests are downy brorce and other sharp-
awned winter annual grasses which reduce hay palatahility
and seriously injure cattle, and perennial grasses such as
quaefcgrass, bluegrass, and perennial ryegrass which
reduce the amount of alfalfa (and therefore the protein
amount) harvested per acre of hay mixture and shorten the
life of the alfalfa stand (USDA, 1977). On this irrigated
-39
-------
land, new stands are commonly planted in August, following
the harvest of a rotational crop. In these new plantings,
competition from winter annual and perennial weeds are
competitors of the seedlings. Such weeds, if not controlled
by a herbicide, prevent the successful establishnent of
alfalfa or reduce the quality of the hay harvested from the
first cutting during the following summer (USDA, 1977).
Pronaxide achieves the most effective control of downy brome
and cuackgrass.
New plantings in the Midwest and Northeast
are commonly made in the spring. Summer weeds threaten
stand establishment and must be controlled at the time
of planting. Current agricultural practice is to plant
a companion small grain crop in the row spacings to
shade out the weed seedlings, as well as to provide a cash
crop for the first year. After the grain is harvested,
the alfalfa extends rapidly into the row spacings,
thereby reducing the potential of future weed infesta-
tions. The plants from the germinating gram seeds can
compete with the alfalfa and therefore sometimes
require herbicidal control.
In established stands, during the fall of
the second through the fourth or fifth year, prcnamice
is applied to the dormant alfalfa to control winter weeds
and grasses particularly when either quackgrass or downy
brome control is needed. Pronamide applied at this time
controls weeds to the extent that another growing season can
generally be expected from the alfalfa CJSDA, 1977).
-40-
-------
the West, only two herbicides, pronaxide and prochara, are
safe on alfalfa seeclir.gs. They can be applied after the 3
trifoliolate leaf stage to reduce competition iron perar.nials
and fall-gerainatir.g winter annuals. Prcnaaiae gives r.ore
reliable control than propharc, due to the latter*s volatility
which requires that it be incorporated into the soil by
water isxediately after application.
In the Midwest and Northeast, the major weed
pest in established alfalfa stands is quackgrass. Although
quackgraas has some nutritional value, its protein content
is significantly lower than that of alfalfa, especially in
the first cutting of the season (USDA, 1977; J. Doll/
1977). Winter annual weeds also contribute to lower protein
content. Thus, the najor benefit from pronamide' s use in
those areas stens from the control of quackgrass.
The control of weeds in alfalfa acreage
increases the per acre protein content of the hay
mixture and therefore reduces the cost of satisfying the
protein requirements for dairy cattle. Recent economic
studies which docucer.t the increased cash value of hay
mixtures composed mostly of high-protein alfalfa as
well as the increased ailk production resulting froa
this alfalfa have probably contributed to increases in
the use of pronaaide (USDA, 1977).
41-
-------
may u^e soil incorporation c£ a preplant, preenergcnt
herbicide instead of planting a companion crop to control
grassy weeds. In this instance, bread leaf weeds are control
led by 2-,4-D8, or dincseb which growers would apply as a
postemergent spray. Fronanide generally cannot be used
as a spring treatment in companion cropping situations
because of its phytotoxicity for the grain in question.
Alternative herbicides are rated only tvo-third
as effective as pronamide for use in established alfalfa
stands (USDA, 1977) . Also, pronamide is the only herbicide
that effectively controls perennial grasses in alfalfa. A
vigorous stand of established alfalfa will shade cut r.ost
summer weeds thereby minimizing herbicide requirements in
established stands. Table III-8 summarizes the features of
pronamide and its alternates.
b. Alfalfa Growr. for Seed
Acreage planted tir. alfalfa which is grown
for seed is a snail segment of the total alfalfa acreage.
As shown in Table 111-I, only 237,000 acreas of all legumes
were grewn for seed in 1977 . Pronamide is* used in this
segment because it controls both summer and winter weeds.
Seed alfalfa is planted in a wider rcw spacing than hay
alfalfa to allow for efficient insect pollination and seed
set. This practice eliminates the seed alfalfa's ability tc
crowd out weeds. Therefore, a high degree cf weed-control is
necessary to maintain the requirements of purity for the
production of commercial seed.
-------
TaMc IIt-0
nclitlv« Cfflcacy of llecbiclto Used on
drops1-/
toll Types
Mocila ConlrnllM?/
HerblclJs
I'J "
nc-w. t
• est el>) IshoJJ
K)^y
Minit-r Anr*i.rkly/Cr«vclly
Or one
Qr.v:3?* UtioJf( CtMaco
fr on
-------
is dodder. This weed net only woa*er.s the alfalfa through
competition but is also parasitic to the alfalfa plant.
Dodder also reduces the quality of the product by ccntermi-
nating the alfalfa seed with dodder seed which is very
similar to alfalfa seed. Mechanical separation does not
effectively separate these seeds, ar.d the marketability of
the contaminated alfalfa seed is drastically reduced ; 'JS2A,
1977). Pronamide is important in this instance since it
provides the better and more consistent control of dedder,
summer grasses, perennial weeds, and winter annual weeds
than any of the alternates.
2. Economics
a* Pr.derlyir.c Assumptions
The analysis determining economic benefits was
performed with data limitations which required several critica.
assumptions. The following are the rr.ajcr limitations ar.d the
resulting assumptions:
(1) There may be a discrepancy
in the estimates of prcnamica use cn alfalfa hay. The
U.S. Department cf Agriculture indicated that $4,SCO acres
were treated with pronamidc in 1977. Rohm and Haas reports
i /
that only 50,0CC acres were treated in 19 7 G— . The
benefits derived were based on the use of prcr.amide cn
94,500 acres since this value reports total use while
the Rohm and Eaas value is based on yearly 3ales.
1/ It is unclear whether the difference represents crowc:.
Tn pronamide usage curing the year cr a real discrepancy
between the estimates.
-44
-------
weed-control strategics for alfalfa and related snail-seeded
leguaes were unavailable. The Agency therefore assuaed
that, if the registration for the use of prona.xide on
alfalfa were cancelled, diuron, propham, sinazine, and
terbacil (alternates identified in Table III-2) would be
used on alfalfa hay and seed crops in the irrigated West.
The Agency also assuced that alternative chenical weed
control practices would not be used on pronaaide-treated
alfalfa hay in the Upper Midwest and Northeast because
no alternative cheaical control for quacfcgrass currently
exists.
(3) The documentation of the efficacy
of alternative herbicides was not precise. The estimated
range in the efficacy of the alternatives was from 50% to 80%
of the control offered by pronaaide. The value of 66%
(two-thirds) represented the mean (Xeitt, 1978), which was
also consistent with expert opinion.
(4) The analysis only considered
the direct benefits attributable to pronanide. No attempt
was sade to quantify such secondary effects as the increased
level of plowdown nitrogen in a pronamide-treated alfalfa
field versus a weed-ir.iested alfalfa field, or the rotational
advantages of a weed-free field (decreased herbicide costs
and increased yields in the following crop). This liaitaticr.
underesticates the benefits of prcnamide use.
-45-
-------
(5) No attempt was made to quantify
the benefits associated with any future increased use
of pronanide in alfalfa and related sir.all-seed-legu.-aes.
If an increased use of pronamide occurs, the benefits
associated with the use of pronanide would increase corres-
pondingly.
b. Costs of Weed-Cortrol Strategies
Pronanide is applied to alfalfa grown for hay
at a cost of $21 per acre; the cost of applying pronar.ide c
alfalfa grown for seed in .the irrigated West averages $25
per acre. If the Agency were to cancel the registration fo
the use of proncniae on alfalfa, alternative herbicides
would be used in the irrigated West.
The alternative chemicals —— diuron, prochan,
3imazine, and terbacil —* are less expensive to apply
but are also less efficacious than prcnanide. The costs of
alternative herbicides on alfalfa, hay in the irrigated
West range from $11 to $13.80 per acre. The costs of
treating alf.vlfa seed crops range fron $9 to $13.30 per
acre. Alternative herbicides would not be used to replace
pronanide in the Midwest and Northeast, since no other
chemical controls cuackgrass in alfalfa hay. The costs of
pronanide and alternative herbicides are reported in Table
III-9.
-------
Ttoble 111*9
Qjftrtlvi Acr* Tr raiment ODiti of Ikctlcldc* Uj«d on Mf«U*
1/
lkrt>lcid«
Pi oncr» I
f) I or co
6lb*i In*
T>.iVk.c1)
Application ft»te7/
Irrigated went Upper Hl«l»jcal/>y>rthcaatl/
lUy Geo! May
Prlco
per
IVXIKtfl/
(XXjTuli
1.0
3.1
1.0
1.)
0.10.4
1.0-1.5
2.4
4.0
1.0
0.S
1.0
dollars
16.00
3.40
3.20
4.00
17.00
(VrrpjtMlvo Coat per AcTC-^rrcetr>:ntl/ .
Irrl'lotC'l Uipcr Hlchicst/Horthust^
|.ay Scod Hay
Collars - -
31.00
11.16
11.80
11.00
13.SO
tt.00^
11.60
ii.eo
9.00
1J.50
21.00
I/ I or I idea bW.Wfoot trafoll In the l^pcr Midwest anJ tbrthc&atern Uiltod fitatea.
5/ Ct «ctiv* injriJltnt.
y li liJca $3.03 per tera awUcatlon coat.
Xj Hfiiiullv# ciiatlc«la K« not used In U>« (Jt>pcv Hlducat^torthcut.
5/ >v«.i»ja over ronjo of bf^Uotion rates.
bCAitcwi USas/^t»i• AjsotoLotnt Tcirt, 1977.
-47-
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c. Impacts
(1) User
The possible cancellation o£ pronartide's
registration for use on alfalfa would result in an annual
loss in net revenue for the producers of alfalfa hay and
*
alfalfa seed who currently use pronaioido. Growers of alfalfa
hay would experience losses in net revenue of $8.05 and
$38.14 per acre in the irrigated West and Midwest and
Northeast, respectively. Producers of alfalfa seed who use
prcnamide would experience losses in net revenue of $36.22
per acre. These changes in net revenue would result frora
the combin&tion of changes in the costs of weed control,
losses in yield, losses in quality (protein in hay and seed
free of weed seeds), and decreased longevity of the stand.
(See Tables IXX-9 through ill-ll].
The total cost to growers could exceed $2.3
million per year for producers of alfalfa hay and seed in
the irrigated Weit and in the Midwest and Northeast (See
Table 111-12). 3ay producers could experience losses in
revenue of approximately $1,573,00 to $543,000 in the
irrigated West, and $1,030,000 in the Midwest and Northeast.
Western seed producers could experience losses in net
revenue of approximately $761,000.
-48-
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•Rible 111-10
Annual Benefits from the Continued Use of Pronamlde
Average Annual Coat of Establishment
over l.tfo of Stand]/
Without Wita
Prononldu Prorwnldo Dlffcrer.ee
Region and Crop
Average Stand Longevity"
Without With
Pronair.lde Pronamlde
Cost of
Cstabllstunent
Irrigated West
Hay
Seed
Upper Midwest/Northwest
Hay
years—
4
5
5
6
100
ISO
100
dollars/acre—
30.19 25.05
37.57 32.45
30.19 25.05
5.14
5.12
5.14
1/ fcitablIslimcnt oosts amortized at 81 interest over varying life spans.
Source: (JSHA/State Assessment Team on Pronamlde, 1977.
-49-
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Tfeble I11-11
Miduest/Vlortheast Hay Seed - Annual Yield, Quality and Value of
Production with the Use of Fronamlde and Alternative Chemicals
Value Per Unit
Yield
Treatment
Pronamlde
Altcmnt Ive
Herbicides
Dlffei once-'
Yield Per Acre
Quality-related Price
Gross Revenue
Hay
Seed 2/
Hay
Seed
Ha*
Seed
Hay
Seed
tons
pounds
percent
dollars
dollars/acre
5.0
436
10.0
5.0
71.50
1.05
357.50
457.00
5.0
402
6.6
3.3
69.29
1.03
346.45
414.06
0
-34
-2.21
-0.02
-11.05
-43.71
Alfalfa hay treated with herbicides produces greater protein per ton harvestd than untreated alfalfa.
A ton of alfalfa treated with pronamlde will contain 10 percent Acre protein than untreated alfalfa and
a Ion of alfdlfa treated with alternative herbicides will ocntaln 6.6 percent more protein than untrc^ie
alfalfa, or 2/3 the increase resulting from the use of pronamlde. Alfalfa pi Ices are adjusted for prole
content, viz., alfalfa hay treated with brings a 10 percent price prtmlr.n over untreated alfalfa.
Ilay harvested frcm untreated fields has a price of $S5.0C per ton. Similar cdjustmcnts are njde for Gee
alfolfa, but tlie price pruniirn result-; from cleaner seed, I.e. reduced proportions of i.«3d seed per
pound of alfalfa sec-d firm tieated fields. Hie adjustments for seed altalfa arc 5 percent for alfalfa
treated with the alternative herbicides. Seed harvcsLcd Cran untreatcxl alfalfa fields has a price
of §1.00 per pound.
2/
- SI nee most alfalfa grown for Heed prductlon is treated with herbicides, the 400 lb. average yield
jx.r acre estimated by U.SilA was assumed to be the yield obtained with the use of alternative herbicides.
^ With resjiect to pronamlde treatment.
-50-
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Table
Alfalfa Grcver Irrracts Associated with Gir.csiiiticr. cf Prcr-arr.ice
Crco <^rd P
-------
(2) Market and Ccnsur.er
If the Acency were to cancel the registration
for the use of prcn-irtide cn alfalfz, the ir.pact cr. the
market would be :ninor. Between 1973 and 1976 , over 27
nillicn acres of alfalfa hay were harvested. It is esti-
mated that only 94,500 acres of alfalfa hay were treated
with, prcnar.ide in 1977. The total production frcm these
acres was not increased through the use of pronaitide.
However, the quality (i.e., protein content per harvested
acre) of the 418 ,500 tons of hay produced frcr. pror.anide-
treated alfalfa was improved ar. average of 11.0 percent
(average of the protein improvement in the irrigated West
and Upper Midwest and Northeast). Even if all cf the
growers of alfalfa for hay who currently use pror.anide were
to shift to other crops as a result cf the Agency's cancel-
lation of pronaaide's registration for use cn alfalfa, the
total production of alfalfa grown for hay in the U.S. would
i /
decrease by less than 1 percent- . This change in the
product\on of alfalfa grown for hay would not he large
enough to result in significant ir.pacts on' the roarfcet.
During 1977, over 93.6 aillicn pounds of
alfalfa seed were produced in the United States. The
use of pronaxide, rather than the available alternative
herbicides, on 21,000 aces of alfalfa seed is estimated to
1/ If all of the acreage treated with pronaaide had teen
withdrawn from production in 1977, alfalfa hay production
would have declined 418,500 tons. This represents only
0.S6% of the 128,874,800 ton average annual production.
-52-
-------
O.S. by 714,000 pounds (0.76 percent). Only 21,000 acres of
alfalfa grown for seed are currently treated with prc-.axide.
The resulting losses ir. production, if tr.e Ager.cy were 'cc
cancel the registration for the use of pronanide on alfalfa
seed, would be small. The impacts or. trie market, in the
event of such a cancellation, would be nir.or. Since the
Agency estimates that the impacts on the xarket of alfalfa
grov»n for seed would be nir.or, it expects that the upsets
on consumers from its possible cancellation of prone-nice' s
registration for this use would be insignificant.
D. Other Crops
There was an overall lack of quar.tifiable eccr.c^ic
benefits for any of the minor volume uses. Therefore, these
uss are addressed ir. qualitative terns.
1. Berries
Pronanide is used on blueberries and the cane
fruit tboysenberries, raspberries and blackberries). This
use is primarily confined to Washington and Oregon where
10,000 acres of berries are planted annually. rronartide is
applied on about 50% of the acreage.
Pronanide is applied to control cool weather
perennial grasses including cuackgrass ar.d weeds. Applica-
tion is nade in the fall after harvesting. Substitute
herbicides offer scna control of the weeds controlled by
pronanide but are sore expensive to use (dichlccenil) ar.d
can be phytotcxic to the borry plant (dichlooanil ar.d
siaazine).
-S3-
-------
2. Wocdy Crnaner.tals
In the United States there are 307,000 acres
of ccrr.ercial nuceries. About 17,CC0 acres wero trotted
with pronamice (P.chn and Haas) to control cocl-season
perennial grasses.
There are nunercus substitute herbicides
available, but none of these control the primary nest
quackgrass, and other grassy weeds as well as pronarcide.
Of the substitutes cr.ly dichober.il and sinarine are
registered for suppression (not control) for quackgrass,
• #
and these two herbicides are phytotoxic to the plants at
the rates necc-ssary for control. In addition, dicr.cbcr.il
cost 2.5 tices xore per acre than pronznide.
3. Burtiudacrass Turf
Pronaraice is used as a selective herbicide
in beraudagrass turf to control annual bluegrass. An
estimated 16 ,000 acres in the southern U.S. were treated
in 1976.
There are no other currently registered
herbicides which selectively control annual bluegrass.
4. Sugarbeet Seed
Sugarbeet is grown for seed in three
western states (Oregan, Utah, and Arizona). The acreages
grown vary in response to projected denand, but usually
4,000 - 5,000 acres of sucarteets are grown for seed annua
Pronaaice is used on about 90* of this acreage.
-------
Prcphara is the only registered substitute
herbicide. Prophara's effectiveness is less than that of
pronaraide, plus the tiding of prophan's application is
critical, as is the need to incorporate prophara into the
soil. These shortcomings were discussed in the section cn
lettuce.
-55-
-------
IV. Rlsk-B^nofit Analysis cf Alternative Ccur3
-------
2» Saller.t Benefit Factors
Pronaraide is primarily used as a herbicide cn
lettuce including endive and escarole varieties. Most use
occurs in Arizona and California, which average 85* of the
total U.S. lettuce production. A loss of 15 million dollars
would result from cancelling the registration for this use.
Alternate chemicals are available but are less effective,
more costly to use, and would require additional hand labor
to attain the same yield per acre. VTnile it is likely that
most of this cost would be assumed by the grower, some cost
might be passed- 'through to the consumer. Due to the lack of
data, it is impossible to quantify the retail price change
that might result from the loss of pronamid*.
Pronaraide is also used as a herbicide on
.alfalfa and on small legumes grown for hay and for seed. It
is use3 mainly in the irrigated West and in the Midwest/
Northeast. If the Agency were to cancel the registration for
this use, growers would lose 2.3 million dollars.
If the Agency were to cancel the registration
for pronanide use in alfalfa, there would be no method for
controlling auackgrass. Pror.araice, the only herbicide
registered for this control, is also thought to increase
alfalfa stand life by at least one year. Without chemical
control, the grower's only alternative to enduring an
infestation of quackgrass is to plow the field under.
-S7-
-------
B. Five Possible Alternate Coerces of Action
Evaluation of the risk and benefit data suggests
five principal regulatory options:
1. Continue registration of all uses.
2. Continue registration of ail uses; amend
the terms and conditions of registration.
3. Continue registration of all uses; amend
the terms and Conditions of registration;
revise the tolerances on lettuce to lower
the dietary exposure.
4. Continue Registration of all uses; amend
the terms and conditions of registration;
revise the tolerances on lettuce to lower
the dietary exposure; require a monitoring
report on residues in milk frca prcnamide
use on alfalfa at 5 year intervals coinci-
dent with reregitration.
5. Cancel all uses.
Tables IV—1 and IV-2 summarize the risks and
benefits of each option. The specific risks and benefits
pertaining to each option are described below.
-58-
-------
1. Continue Registration of All Uses
Adopting Option 1 would indicate that the
Agency concludes that the benefits associated with each
use outweigh the respective risks and that therefore, none
of the uses of pronanide cause unreasonable adverse effects.
This option would return pesticide products which contain
pronaraide to the registration process. Thi3 option would
not reduce the risk of cancer associated with the use of
pronaraide. The potential lifetime risk of cancer frcm all
— 6
sources would remain at 3 x 10 for oral ingestion,
assuming dietary lettuce residues at tolerance levels of 2.0
prn. Applicator risk would remain at 9 x 10~^ for
alfalfa use and 7 x 10~3 for lettuce use. This option
would not result in any adverse economic impacts and would
retain the usefulness of pronanide as an economical, effec-
tive tool for the control of weeds in lettuce and alfalfa.
The choice of this option would indicate that the Acency
is willing to tolerate a level of risk greater than the
levels of risk estimated in the other options in return for
the highest possible benefits.
-59-
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and Ar.ond tne Torrr: u.-.c Ccr.c i c .one c: ;;oc:::r::.cr.
The adoption of option 2 would indicate that
the Agency concludes that the benefits of pronanide's
continued use outweigh the risks from oral ingestion.
However, without a diiinuticn in the exposure to applicators
(Tables II-2 and II-3), and considering the projected
incidence of tunors which result fro.-a it (Table II-5) , the
benefits derived from pronaraide do not outweigh the risks to
this applicator population.
a. Discussion of Procosed P.estrictions to
Reduce Applicator Exposure
(i) CI ccr if-' ?r cr. sr. i £ c 2 s a Pestrictod-
Use-?ecticice ar.c Racuira AcclicaTor
Certl f ication
This option is designed to move the use of
pror.aaide cut of the open market and to restrict its use to
certified applicators.^ Since pronanide is marketed
alaost entirely for use by professional applicators (lettuce,
turf) and private applicators (alfalfa, ccrrjnercial nursery),
restricting its use by homeowners should not-affect the
pesticide industry's profits. In theory, requiring applica-
tors to be certified to use pronaaide will reduce the hazard
frca its use because unskilled applicators will net be
allowed to use it.
1/ The pes t ic ice apol icator cert if icat icr. process grants
certificates for two types of applicators: professional
and private.
-60-
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cur: ¦" - "t\n ir.a zC
?ronac:ie
Data froQ Table II-2 sr.ows the theoretical
exposure range that applicators receive during mixir.g and
applying pronamide. Table II-5 indicates the risk levels
and the expected cancers associated with the application
of prcnanide to lettuce and to alfalfa. Under the assump-
tion used in projecting exposure values. 35J of the sod/ is
normally clothed. Excluded from normal clothing are the
hands forearms neck face, upper chest, and hair. Requir-
ing the use of a protective overgarment and gloves will
leave only 3-55 of the body exposed. Thu3 an additional 3C%
of the body, normally uncovered would be protected by a
one-piece protective overgarment hat, and gloves. A
corresponding reduction in risk could be contemplated
from this reduction in exposure (Day. 1978).
The risk levels calculated frcm experiments
using pronaaide (JCremiaski, 1S78) and similar pesticides
(Jegier. 1964 Wolfe. 1967 Wolfe. 1975 ) provide a range of
values roughly two orders of magnitude apart in applications
on both lettuce and alfalfa (Table II-5). The Agency faela
that the average level of risk is more closely represented
by Jegier. Even the assumption of this median level, 2 x
10"^ (lettuce applicators) reflects a high estimate of
risk.
The economic impact of this regulation would te
slight. Most applicators commonly wear protective garments.
-------
(iii) Scculre the For.u 1 ~ t ? or, of P-cr. amide' , ^
(Wettaale Pewcer, i'..ater wOlu&.e bags —
Although there is always a air.lxun level of
exposure, the projected range in levels of risk for lettuce
and custoc applicators and alfalfa growers (Table II-5) is
greatly influenced by the degree of care exercised in nixing
the pesticide solutions. The adoption of this option would
reduce the total exposure froa nixing by at least 955 (Day
1978). Water soluble bags containing pror.anide would be
added to the water: when the bag dissolves, the forsulation
would then be released and aixed as it is currently done.
There would be no duct generated frcs pouring or frex mxir.~
the product. Although the exposure received during applica-
tion would not be reduced by the adoption of this option, as
shown in Tables II-2 and II-3- the exposure related to
application is in the order of 2 orders of magnitude les3
than the exposure received during nixing. Thu3, rxzk3
related to application would be about the sane as oral risks
if this option were adopted.
Adopting this option nay cause a slight increase m
costs. Rohn and Kaa3 has predicted an increase of roughly
tO.25 per lb of formulation, if packaged as water colutlo
bags (Srneainski 1978). The total increase in the ccst cf
_]_/ This restriction would apply only to the wettafcle
pewder fcrnulaticn. Granular fornulations tz net present
the dust problems (Cay 197S : Jasper, 1973 ).
-62-
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the application of Kerb 50 V would be $C.50 to $0.65 per*
acre for alfalfa and $0.20 to $0.55 per acre for lettuce.
These costs 3hould not significantl/ alter the econoalc
benefits of pronanide
The option is useful because it is a passive
protective aeasure. Applicators wculd not need to take sore
stringent protective aeasures than they already do. Also,
there would be no need for additional enforcement activities
to monitor coapliance with the requirener.t.
C!y) Cancel Hand Scray Use
This restriction would eliair.ate exposure to
applicators froa hand sprays. The values in Table II-3
represent the exposure which applicators receive froa
sitting on a tractor pulling a sprayer It is reasonable to
assume that soae of the factors which generated these values
would also apply when the applicator is standing holding a
hand spray, except that the applicator is within 1 foot of
the spray Instead of the several :'eet away froa it on a
tractor pulling a sprayer. Thi.\ would increase the exposure
by several orders of magnitude. Thus, an applicator using
spot-treatxent for alfalfa cr for any of the other uses nay
receive froa 0.1 ag/kg to 1.0 ag/kg derxal exposure and a
corresponding increase in inhalation exposure.
-63-
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The cancellation of the registration for this use
would have a negligible impact on the economics of pronamide.
Pronamide is used in hand sprays infrequently, if at all, in
spot-treating alfalfa fields, and it is not used at all in
lettuce fields. Cancellation would cause the grower to use
tractor spray equipment for all pronamide applications. No
significant difference in exposure is expected when comparing
large agricultural tractors to smaller nursery-size tractors
which night be prevalent in applying pronamide for other
uses than on lettuce and alfalfa (Day, 1978). Also if
packaging were to be limited to water soluble bags, it would
becone illegal for an applicator to tear open the bag in
order to mix a limited amount of spray.
3. Continue Registration of All Uses: A,T.end the
Terms and Conditions of Registration: Revise
the Tolerances on Lettuce to Lever tne
Dietary Excosure
Adopting Option 3 would indicate that the Acency
concludes that the risks associated with the ingestion of
residues of pronamide, as the pesticide is presently registered,
outweigh the benefits of its continued use, but that by revising
the tolerance for lettuce which is established by EPA under the
Federal Food Drug and Cosmetic Act (FFCCA), the exposure and
the consequent risk of tumor production will be reduced tc a
level at which the benefits frcru the use of pronamide would
outweigh the risks of ingesting its residues.
-64-
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There are five food sources through wntch people
may ingest residues of pronanide (Table II-l). The cunulativ?
total of four of these (berries, eggs, meat, ar.d r\ii:< and
otiicr dairy products) is 0.0001 ng/pcrson/cay (Day and Collier,
1978). Residues fron the fifth food source, lettuce, :nay vary
from 0.0008 to 0.01 ag/person/day depending on the rate at
which the pronaniiae is applied, the method of application,
environmental factors and most significantly, the oreharvest
interval.
Based upon a 35-day preharvest interval, and a
2 pen tolerance in lettuce, the hypothecical lifetime
incidence of cancer in the U.S. population from the ingestion
of residues of pronanide from all food sources is 3 cancers
per nillion people. However, by assuming other than tolerance
levels in lettuce, the incidence of cancers due to pronanide
can be decreased (Table II-5).
There are reasons for assuming that the actual
residues of pronamiae in lettuce correlate with the residue
levels calculated from a 14C-pronanide time decline curve.
These reasons include both narket basket analyses (Reric,
1977) and monitoring studies (Alford, 1978) which demonstrate
that head lettuce with a preharvest interval of at least 60
days will have measured residues of < 0.1 pp^i. Accordingly,
65-
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since pronamide is normally applied as a pre-emergent at the
time of planting, there is, when normal agricultural practices
are used, a preharvest interval greater than the minimum of 35
days.
The Residue Chenistry Branch, EPA, upon reevaluat-
ing the Rohn and Uaas data, has suggested a revision in the
lettuce tolerance. This revision would lower the tolerance to
1 npm wich a requirement that the lettuce be treated with
pronamide as a pre-emergent and that the minimum preharvest
interval be 60 days (Cumramings 1978). This tolerance will
force all residues of pronamide to be less than 1 pom and
will lewer the exposure to people. The reduced exposure
will decrease the projected turcor incidence to a range of
from 1 tumor per million people to 1 tumor per 10 million
people (Albert, 1978).
Spring and sunner leaf lettuce which makes up
5% or less of the total lettuce grown in the U.S., can have
a growing season of less than 60 days. If the Agency were
to adopt this option, the growers of this type of lettuce
would be forced to use a substitute herbicide to control
weeds. However, since substitutes are readily available and
reasonably economical to use, the impact of the Agency's
adoption of this option on the growers of this type cf
lettuce would not be significant.
-66-
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4. Continue istrc.tion of all uses, Arr.ond the
terrcs ar.c
conditions ot Roc lc
tracion. P.evise
the -oior
nnccs on .oituce to
icwor t.io dio.a
r v
exoocurc;
Hocu ire *i mo niton r.
c r^cort on
res ;cu'.c
m rrc:.-. cror.^-'i
•j'? use on aif-1
at L> vear
intervals co:r.ciaor.
- vi-r. r®racist
ra-
t ion
The data available to the Agency indicates
that the present use of prcnamide on alfalfa presents a
taininal hazard, due to the extrex.ely snail percentage of the
total crop being treated with the herbicide. However, the
Agency does net feel that this relatively safe level can be
maintained if the'use of pronamide beccr.es as widespread as
predicted by Rohn and Haas (Rarig, 1S77). The exposure to
the United States population will increase as pronamide is
integrated into alfalfa treatments in a wider area of the
country. Recently conducted milk and alfalfa hay studies
(Kutz, 1978) have shown low residues of pronamide in alfalfa
{approxinately 0.1 ppra) and possible residues in mil/c (less
than 10 ppb). The increased use of pronamide could result in
higher residues, and In higher dietary exposure for a larger
segment of the population. Accordingly, the Agency plans to
require, at 5-year intervals coinciding with reregistration,
surveys for residues of pronamide in mill: frcn dairy cattle
fed alfalfa treated with pronamide in the areas where
pronamide is marketed.
The economic impact of this cpticn would be ar.
expenditure by the registrant estimated at loss than $10,CCQ
every five years.
-67-
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5. Cancel All Uses
Adopting Option 5 would indicate that the Agency
concludes that the risks associated with all of the uses
outweigh the respective benefits and thereby result in
unreasonable adverse effects. This option would eliminate
all of the uses of pronanide. Cancellation would eliminate
all of the cancer risk associated with the use of pronaraide
(Tables II-4 and II-5), but at a cost to growers of 15
million dollars per year for lettuce and 2.2 million dollars
per year for alfalfa (Tables III-7 and 11-13). Sorae
percentages of the added ccst of production night ce passed
on to the consuaer, particularly in the case of lettuce.
However, price information and elasticity are not adequate
to predict the incremental cost additions to retail prices
that would result from the additional costs to the growers
i /
(Zygadlo, 1978)— . The choice of this option would
indicate that the Acer.cy is unwilling to tolerate tho level
of risk associated with any use of pronamide.
This option would increase the use of alternate
chemicals. In lettuce# the two major alternatives would
be prophaa and benefin, used either singularly or in combi-
nation. In alfalfa, if the pest weed is not auackgrass for
1/ In acciticn to tne cost increases for the major uses Lr.
alfalfa and lettuce, there would likely be some additional,
although urcuar.tiCled, cost increase cor the prcductu of
"miner" uses oi prcnanide.
-60-
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which no other herbicide is presently registered, propham
would again be used along with diuron, chloropropham,
sircazir.c, and terbacii.
Propham is currently under H?AR review as a
suspected oncogen. Studies used in this review have r.oc
been reviewed by the propham RPAP. support tea® so no conclu-
sions on the validity of the studies nor on the oncogenic
potential of the chemical can be mace now.* Prcphaa may
also be a teratogenic agent. A study on file indicates that
a teratogenic response was achieved in mice. Again, the
study has not been reviewed by the propham RPAil support
team, so no conclusions can be drawn (Gardner, 1978).
Pinally, certain toxicological studies have been conducted
on propham by Industrial Bio-Test Laboratory. These tests
include many of the registration requirements for acute and
subacute tonicity. Accordingly, until the registrant of
propham can validate these studies, they cannot be used to
evaluate the toxicolcgicai profile of propham (Gardener and
Sandusky, 1978).
Benefin, the other primary alternate to pronanide
for use ir. lettuce is not currently under RPAR review.
However, a profile of the toxicolcgicai characteristics of
benefin indicates that there is a potential fcr adverse
reproductive effects. Although not well documented, there
are also indications that benefin may cause nutacenicity,
oncogenicity, and neurotoxicity.
-69-
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Chloropropham is a third alternative to pror.amide
for use in alfalfa There are data gaps chloropropham
regarding its potential for teratogenic, nutag^nic, and
reproductive effects; chloropropham has also been reported
to be oncogenic if it is used along with a promoting agent
(Gardener and Sandusky, 1978).
C. Comparison of Potions
In selecting a regulatory option, the Agency
must decide which of the proposed options achieves the most
appropriate balance between risks and benefits. This
decision turns in part on the key factual elex.ents sur-.arirad
above, and in part on the relative merits of each proposed
opt ion.
Option 1, which would continue the registration
for all uses and Option 5, which would cancel the registra-
tion for all uses, represent all or nothing approaches to
regulating. With the adoption of Option 1, the Agency would
neither do anything to reduce the estimated risks, nor would
it otherwise recognize that the RPAR review confirmed the
presumption of oncogenicity. By contrast, Option 5 would
succeed in eliminating risk, but only by substantially
increasing the costs for the users who would be forced to
use alternate pesticides. Also, the adoption of this option
would eliminate a pesticide which nav prove to pose less of
a risk than the alternatives.
-70-
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Cptions 1 and 5 are even leas supportable in
light of the range of measures described in Options 2
through 4, v/nich reduce risk without a significant impact cr.
benefits and avoid the costs associated with a cancellation.
Cption 1 would be reasonable only if the benefits clearly
outweigh the risks# and if reductions in risk cannot be
achieved without unacceptable consequences for the benefits.
Cption 5 would bo reasonable only if the risks clearly
outweigh the benefits, and if significant reductions in
risks cannot be achieved by measures short of cancellation,
without unacceptable inpacts on the benefits. The facts
indicate that neither situation prevails and that alter-
native options are available which are environmentally and
economically sound. Therefore Options 1 and 5 are not
reasonable regulatory measures in this case.
Option 2 deals with the issue of risk to the
applicator through exposure by reducing this exposure
and risk with amendnents to the terms and conditions of
registration. This option, however, dees not lessen
certain dietary risks that are created thrcugh the use
of pror.amide in lettuce and alfalfa.
Cption 3 presents a control for lessening the
ri3k from the use of this herbicide on lettuce and Option
4 combines the previously mentioned controls with an added
-71-
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Itble IV-I
Kcflulttory Options *n4 IUiIojm Ctncer llik Incidents Predicted trera Prontaldo Use
Dpi ton
HTMfi AppHcitort
IttluciTiyl I extort
Ccnjur :r
|. Contlnuo Hcolttrttton
All Ui:i
2. Continue Registration
All Um, A.rend the
Icruj jnd CondltIon
cf RcutUrjtlon
I. Protective Clothing
II. Miter Solnblo Ptcktglng
III. Certified Ai'pllectori/
Iv Restricted Ui«
). Continue Registration
Al) U;es, Ajtend tho
Teres c Clct«ry (ipoturo,
Rc<|ulic i Monitoring
Biport on Keituj'i In
hlH IfOJ Tronjctldc
Dio on Alftlf* Jt 5
1c»r InlcrvjH Coincident
UKIi RcjlitritIon
1.9) I 10
• S
*.» X 10
3.01 I 10
-6
3.01 X 10
•6
8.1) 110
8.28 I 10
-1
Mo DMA
Reduced fiposur# Fxpcct&d
Sioe it Option 2 plus
IJJ I I0"4
8.20 K 10-'
110 OAi.l
Reduced fipoiurc (ipcctcd
1.21 I 10
to
1.0) I 10
Siac it Option 3 plus
Monitoring for Potential
Dlcttry Increase result-
ing from (ncrciicd
pronjmldc jse.
6. Cancel All Uiti
-------
T46U 17-2
Pronaalde ReguUtory Options and £concatc Iap4Cts
Optigw
ic rcu-.: /
1. Reregister All
Uses
2.. Contlr.ue ."!*<)< *f»t1cn All
Uses. *oend thi» lcrj *n<3
Conditions of Re-jUtntlon
t. Protective ClotMr.g
11. «4ter Soluble Picking
Lettuce
Alfalfa
lettwce
Alfalfa
lettuce
Alfalfa
cr
licne
None
Ho significant Irtuct
No significant <*3>4ct
Acp11c4t1cn Cost ^rcr*»se
S.SS/tcre - Ho long tern
econsitc l»p4ct. «et profit
loss will be Insignificant.
Application Ccst Ircredsj
S.6S/4cr* No -cng un
economic i?3
-------
precaution necessitated by the potential for dietary expo-
sure froa the use of the herbicide on alfalfa that i3 fed
to dairy cattle.
V. Recoaaer.ded Regulatory Action
The Agency recomaends Optiou 4 as its regulatory
action:
Continue Registration cf all uses. Asend the
terns ar.d cor.d itior.3 of registration (V.'ote).
Revise the :aler^r.ce3 cr. i.e'c.uc-3 :c lover tne
Diotarv ".x-,:03u.-e. r.ecuire a :on::cnr,: report
on residues m :'rc: crcnaciice use cn al; alfa
at 5 year intervals coincident witn reregistratlor.
The analysis of risks and benefits froa the
continued use of pror.aaide in both lettuce ar.d alfalfa
indicates that the primary problea is the exposure incurred
by applicators of the pesticide. The analysis also indi-
cates that a risk froa the continued use of pror.aaide exists
for the general population of the United States frcx eating
lettuce which bears residues of prcraaide. The aaount of
thi3 ri3k for the general population is auch lower than the
amount of risk which exists for applicators of pronanide.
Option 4 represents a responsible regulatory assessments if
the risks and the benefits cf the continued use cf pror.aaide
and the balance- between thea that shculd be properly 3truck.
•(i) Classify Pror.aaide as a restricted use pesticide and
require applicator certification.
(ii) Hequire the use of protective cicthir.g during aiaing
and application of Prcnamde.
Ciii) Require the foraulaticn of prcnaaide (Vettable
Pcwder) in water soluble bags.
(iv) Cancel hand 3pray use.
-------
Option 4 has distinct components, each of which is
designed to reduce the risks of cancer which are associated
with the exposure to pronamide without sinultaneously
creating the adverse economic, social and environmental
impacts associated with cancellation. The first requires
applicators to become aware of the hazards involved and
denies the use of the pesticide to untrained, non-skilled
applicators. This requirement would apply to all pronamide
products. This option also requires the use of protective
overgarments thereby allowing for the safe use of the
pesticide during the processes of mixing and applying it
which are the periods of potential high exposure. The option
would also require the packaging of pronamide as a wettable
powder In water soluble bags. This would lessen the exposure
which results from opening the bag containing the pesticide,
and from mixing it. In practice, the adoption of Option 4
would eliminate applying pronamide with a hand spray because
of the requirement that the pesticide bo produced in bags of
one pound or more in size. Hand spray ir.g, as practiced, is
for spot treatment using a total capacity of 1 gallon or
less. Spot treatment requires quantities of pronamide in
ounces, a feasible mixing capacity for a hand spray.
Restricting the formulation to one pound or larger water
soluble bags, which are to be used intact, essentially
eliminates the hand spray problem in theory. The option's
specific cancellation of har.c spraying eliminates the
problem in fact.
-------
treated lettuce presents a small nuaerical risk, if it 13
assuaed that dietary residues are la the lower part of the
residue apectrua exenplified in Tabic II-2. However, because
sufficient data is not available to support this aasuaption,
tt is iacunbent upon the Agency to act on the side of safety.
Consequently the Agency nuat act to insure a lowering of the
actual asount of residues consuaed by people. To do this
the Aceacy proposes to require codifications of the label aa
follows:
1. Applications of pronaaide are restricted to pre-
emergence only;
2. The application rate cannot exceed 2 pounds active
ingredient per acre;
3* Pronaaide is not to be applied to lettuce varieties
which will be harvested sooner than 60 days from
treatment.
This should lower the residues in lettuce to between the
0.8 ppo level and the aensitivit7 level of 0.01 ppm. Aa a
resul; the ultimate risk of cancer frca the ingestion
of lettuce treated with pronaaide should be reduced to
under one per aillion population, possibly approaching oce
per ten aillion population. At this level, the Agency
feels that the benefits will outweigh the riaka and that the
continued use of pronaaide can be supported.
76
-------
Since as equilibriua between benefits and rinks appears
to be reached for alfalfa except for the risk to applicators,
the Agency does not new feel cocpelled to exercise any
further restrictions on this use. However, the Agency is
concerned that a hazard aay develop froa the residues of
pronanide ia nilk. if pronaaide's aarket share grows to
levels predicted by the registrant. The literature which i3
available indicates that pronanide has not been detected in
ailk at a sensitivity of 0.01 ppa (Xutz, 1973: Rarig,
1977). However, in an Agency study using sophisticated gas
chrcoatography/nass spectrometry, some low residues of
pronaaide (<10 ppb) cay have been detected is silk. These
results have not been confirmed. Therefore, the Agency will
require a aarlcet basket aonitcring study of residues of
pronaaide in alfalfa and allk to be subaitted with every
reregistration application for pronaaide. If this monitoring
shcv3 that concentrations of prouanide are increasing, the
Agency will reevaluate the decision on alfalfa.
This option does not iapo3e any severe ecccoaic limita-
tions on the use of the procaaide. The priaary econcaic
iopacts of this option will be in the cost of water soluble
packaging and in the eliainatioc of the use of pronaaide on
lettuce grown in less than 60 days. As discussed in Section
17, the additional cost per pound of active ingredient ia
water soluble packaging is estimated to be 50.50 (Srzeaecsk:.
1978). Computing this on a per acre cost equals an additional
-77-
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coat of roughly $0.50 per acre for lettuce and alfalfa.
Thi3 additional cost la negligible when compared to the net
benefits of pronaaiide which are. at a minimum, $70 per acre.
The remainder of the costs necessitated by thi3 action are
also negligible. These co3ts , as pointed out in Section IV,
accrue mainly to applicators and do not cause thea to
purchase sophisticated equipment, but only to use clothing
and equipment now available.
' The alternatives which would be used for the portion of
lettuce production to be excluded from treatment with
pronamide would probably not provide any worse hazard to
the public. Propham, although its hazards are not totally
documented toxicologically, 3hould not, in the small segment
of lettuce affected, prove more hazardous to the applicator
or"to "the"cdRsumerT" Benefin, also should not prove to be
more of a toxicological hazard than pronamide. Taken
singularly, these alternatives, propham and benefin, would
not be as effective on lettuce as pronamide would be. To
provide a spectrum of* weed control which is comparable to
pronamide, these two chemicals must be tank mixed. Thi3
diminished capacity for weed control by the grower should
only exist until data i3 provided to assure the Agency that
residues found in short season lettuce and in transplant
lettuce do not exceed the one ppm tolerance. Because of the
relatively small proportion of the lettuce crop involved,
the long term consequences of this action should not result
in any large disruption in the economic of lettuce production.
. -73-
-------
Ia conclusion, the adoption of the recooaended regula-
tory action would ser7e to aininize the potential for risk,
and would also enable the benefits to regain near their
current levels.
79-
-------
Albert, Roy Z. , M.D., Chairr.cn, Carcinogen Assessment
Group (CAG), EPA, October 19, 1978. The CAG's Risk
Assessment cn Pronamidc.
Albert, Roy Z., M.D., Chairman, CAG, EPA, April 7, 1978.
Memorandum to Richard Troast, Special Pesticide Review
Division (SPRD), EPA.
Albert, Roy E., M.D., Chairman, CAG, EPA, July 28, 1978.
Registration of Tumor Initiating Conpounds. Memorandum
to Edwin L. Johnson, Deputy Assistant Administrator (DAA),
Office of Pesticide Programs (OPP), EPA.
Albert, Roy E. , M.D., Chairman, CAG, EPA, March 17 , 1977.
Preliminary Review of Oncogenicity of Pronanido.
Alford, Harold G., Regional Coordinator, Pesticide Impact
Assessment Prcgram, Cooperative Extension, University of
California, Berkeley, June 6, 1973. Letter to Richard Troast,
SPRD, EPA with attachments.
Clark, G.N., O.M. Scott and Sens, June 2, 1977. Request for
60 Day Extension #2 [30000/14] OPP, EPA.
Coberly, R. , Toxicology Branch, Re? is^rat ior. Division, OPP,
EPA, November 29, 1974. 3,5-dichloro-N-(i-l-dinethyl-2-
propynyl) benzaaide (Kerb), Memorandum to Jesse E. Mayes,
Acting Chief, Coordination Branch, Registration Division,
EPA.
-80-
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Cummings, J.G., November 7, 1978. Pronamide RPAR - Regula-
tory Options. Memorandum to Richard Troast, S?RD, CPA.
Day, H.R., Septamber S, 1978. Pronamide Exposure - Snail
Tractors. Memorandum to Richard Troast, SPRD, EPA.
Day, H.R., September 28, 1978. Applicator Exposure Reduc-
tion Protective Clothing. Memorandum to Richard Troast,
SPRD, EPA.
Day, H., and C.W. Collier, EPA, July 6, 1978. Pronamide
Exposure Analysis.
Day, H.R., November 13, 1978. Rohn and Haas Comments on
Pronamide Analysis. Memorandum to R. Troast, SPRD.
Dubin, Z.M., March 17, 1978. Consultant Pathology Report on
Rohm and Baas Compound "Pronamide (Kerb)" Used in reeding
Experiments in Mice and Rats.* Submitted to the EPA
Carcinogen Assessment Group.
Kutz, F.W., Ph.D., September 29, 1978. Snvircrmental
Monitoring Study for Pronamide. Memorandum to Richard Troast,
SPRD, EPA.
Potrep*a, Robert ?., MED, CZD, EPA, February 17, 1977.
Validation of Pronamide (Kerb) Chronic Feeding Studies.
Memorandum to Richard Troast, SPRD, EPA.
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Rarig, F.J., Vice-President, Rohm and Haas Co., August 29,
1977. RPAR Rebuttal of Pronamidc (OPP-30000/14).
Rohn and Haas Co., September, 1974. Application for Permanent
Tolerance for Herb: Alfalfa. Confidential. EPA Pesticide
Petition SF15S2.
Rohm and Haas Co., April, 1971. Application for Permanent
Tolerance for Herb: Lettuce. Confidential. EPA Pesticide
Petition 1P1139.
Ryan, James B., Research Manager, Agricultural Chemicals -
irortl: .Viaricz, F.chm and izzs Co., December S, 1977. Herb
Benefits Document for the Rebuttal of the Presumption
Against Registration of Pronamide (Kerb). EPA Dockett No. 1
OPP-30000/14. -----
Swisher, E.M., Rohm and Haas Co., May 19, 1977. Request for
60 Day Extension, *1(30000/14] OPP, SPA.
Troast, Richard, SPRD, EPA, January 14, 1977. Biological
Activity of KZR3, Export Cses Kerb. Record of Communication
with Dr. Ely Swisher, Rohm and Haas Co.
OSDA/State Assessment Team on Pronamide, August 29, 1977.
Pesticide Impact Assessment Prcnamide (Kerb). Coordinated
by the Office of Environmental Quality Activities, OSCA.
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