Return
to Cyhalofop-butyl
Index Page
Activity:
Herbicide
(aryloxyphenoxy propionic acid)
Structure:
Adverse
Effects:
Body
Weight Decrease
Carcinogenicity:
Kidney
Endocrine:
Testicular
Endocrine: Thymus
Eye
Kidney
Liver
As
of February 17, 2005, tolerances
for Cyhalofop-butyl, Cyhalofop acid
and the di-acid metabolite, are permitted in or on 2
food commodities in the United States - listed at
the bottom of page
|
Body
Weight Decrease
(click on for all fluorinated pesticides)
-- Acute Dermal (Rat)
LD50 & 35000 mg/kg (2.5 x the limit dose) Chromodacryorrhea was
observed in 2/ 5 males on day 2 only. Delayed
weight gain was observed in all rats, with the females being most
affected. There was no dermal irritation. Toxicity Category
IV
Ref: Federal Register: June 4, 2002. Cyhalofop-butyl;
Time-Limited Pesticide Tolerance. Final Rule.
http://www.fluoridealert.org/pesticides/Cyhalofop-Butyl.FR.June4.02.htm
Carcinogenicity:
Kidney
(click
on for all fluorinated pesticides)
-- Chronic dietary
all populations: Carcinogenicity in mice
based on kidney effects in females including tubular dilatation,
chronic glomerulonephritis, and hyaline casts. LOAEL =
10.06 mg/kg/day.
Ref: Federal Register. September 27, 2001.
Cyhalofop-butyl; Pesticide Tolerances for Emergency Exemptions.
Final Rule.
http://www.fluoridealert.org/pesticides/Cyhalofop-butyl.FR.Sep27.01.htm
Endocrine:
Testicular
(click
on for all fluorinated pesticides)
"Palatability
and Four-Week Dietary Probe Study in Beagle Dogs"; (M.J.
Mizell, K.T. Hart and J.W. Crissman; The Toxicology Research Laboratory,
Health and Environmental Sciences, The Dow
Chemical Company, Midland, MI; Study ID. DR-0298-8876-004;
9/11/90); In a preliminary palatability study, one beagle dog/group
received 250, 500 or 1000 mg/kg/day of XRD-537 nBu (Technical)
(AGR 276541, purity: 98.2%) for up to 2 weeks... In the second
study, 2 beagle dogs/sex/group received targeted doses of 0, 35,
100 or 350 mg/kg/day for 4 weeks. Based on the food consumption,
the low dose animals received doses of 36, 36, 34 or 53 mg/kg/day,
the intermediate dose animals consumed doses of 85, 86, 133 or
138 mg/kg/day and the high dose animals received doses of 193,
203, 37 or 292 mg/kg/day, respectively...
Gross examination of the tissues revealed
slight to very severe atrophy of the thymus in a dose-related
manner... In the microscopic
examination, multifocal vasculitis and thrombosis was noted in
the kidneys of the 2 high dose males and one intermediate and
one high dose female, respectively. Diffuse atrophy of the thymus
ranged from slight to very severe in a dose-related manner for
the males in all of the groups and from moderate to severe for
the intermediate and high dose females. In
the testes, spermatogenesis was moderately to severely reduced
in the high dose males with a concomitant increase in multinucleated
spermatids. Apparent target organs:
thymus and testes; Possible adverse effect: atrophy
of the thymus and reduced spermatogenesis in the testes;
NOEL can not be determined; Study supplemental. (Moore, 11/20/00)
Ref: February 16, 2001. California Environmental
Protection Agency Department of Peticide Regulation. Medical Toxicology
Branch. Summary of Toxicological Data. Cyhalofop-Butyl. Chemical
Code # 5748, Tolerance # 52840 SB 950 # New A.I.
http://www.fluoridealert.org/pesticides/Cyhalofop.butyl.CA.Tox.2001.pdf
Endocrine:
Thymus
(click
on for all fluorinated pesticides)
"Palatability
and Four-Week Dietary Probe Study in Beagle Dogs"; (M.J.
Mizell, K.T. Hart and J.W. Crissman; The Toxicology Research Laboratory,
Health and Environmental Sciences, The Dow
Chemical Company, Midland, MI; Study ID. DR-0298-8876-004;
9/11/90); In a preliminary palatability study, one beagle dog/group
received 250, 500 or 1000 mg/kg/day of XRD-537 nBu (Technical)
(AGR 276541, purity: 98.2%) for up to 2 weeks... In the second
study, 2 beagle dogs/sex/group received targeted doses of 0, 35,
100 or 350 mg/kg/day for 4 weeks. Based on the food consumption,
the low dose animals received doses of 36, 36, 34 or 53 mg/kg/day,
the intermediate dose animals consumed doses of 85, 86, 133 or
138 mg/kg/day and the high dose animals received doses of 193,
203, 37 or 292 mg/kg/day, respectively...
Gross examination of the tissues revealed slight to very severe
atrophy of the thymus in a dose-related manner... In the
microscopic examination, multifocal vasculitis and thrombosis
was noted in the kidneys of the 2 high dose males and one intermediate
and one high dose female, respectively. Diffuse
atrophy of the thymus ranged from slight to very severe in a dose-related
manner for the males in all of the groups and from moderate
to severe for the intermediate and high dose females. In
the testes, spermatogenesis was moderately to severely reduced
in the high dose males with a concomitant increase in multinucleated
spermatids. Apparent target organs:
thymus and testes; Possible adverse effect: atrophy of the thymus
and reduced spermatogenesis in the testes; NOEL can not
be determined; Study supplemental. (Moore, 11/20/00)
Ref: February 16, 2001. California Environmental
Protection Agency Department of Peticide Regulation. Medical Toxicology
Branch. Summary of Toxicological Data. Cyhalofop-Butyl. Chemical
Code # 5748, Tolerance # 52840 SB 950 # New A.I.
http://www.fluoridealert.org/pesticides/Cyhalofop.butyl.CA.Tox.2001.pdf
Eye
(click
on for all fluorinated pesticides)
Based on the findings of acute toxicology studies with two similar
products, and by extrapolation from the characteristics of the
individual constituents in the product, it is expected that Barnstorm
Herbicide would be of low acute oral, dermal and inhalational
toxicity. It is likely to be a slight skin irritant and a
severe eye irritant, but not to be a skin sensitiser (page
5). ... Barnstorm Herbicide is expected to be of low oral, dermal
and inhalational toxicity. It is expected
to be a severe eye, and slight skin irritant,
but not a skin sensitiser (page 9).
... Risks to workers during use.
The main acute risks arising from exposure
to Barnstorm Herbicide are slight skin irritation and severe
eye irritation. Mixer/loaders may be exposed to the product
by inhalation or by skin and ocular contact. The
main risk during this activity is skin and eye
and respiratory tract irritancy (page 17). ...Eye protection is
indicated for handling undiluted product due to the potential
for severe acute eye irritation (page 18). ... SAFETY
DIRECTIONS • Will damage the
eyes (page 35).
Ref: July
2005 - Evaluation of the new active Cyhalofop-Butyl in the product
Barnstorm Herbicide. Australian Pesticides and Veterinary Medicines
Authority (APVMA). Canberra, Australia.
http://www.fluorideaction.org/pesticides/cyhalofop.butyl.aust.2005.pdf
Kidney
(click
on for all fluorinated pesticides)
-- Chronic dietary
all populations: Carcinogenicity in mice
based on kidney effects in females including tubular dilatation,
chronic glomerulonephritis, and hyaline casts. LOAEL =
10.06 mg/kg/day.
Ref: Federal Register. September 27, 2001.
Cyhalofop-butyl; Pesticide Tolerances for Emergency Exemptions.
Final Rule.
http://www.fluoridealert.org/pesticides/Cyhalofop-butyl.FR.Sep27.01.htm
-- Dermal,
Long-Term, Carcinogenicity in Mice:
Kidney effects in females including tubular dilatation, chronic
glomerulonephritis, and hyaline casts at
the LOAEL of 10.06 / 10.28 mg/kg/day, M/F.
-- Inhalation,
Short- Term (1-30 days), Subchronic
Feeding Mice: Enlarged kidneys in swelling of the proximal tubule
cells in 4/12 mice at the LOAEL of 14.1 mg/kg/ day.
-- Inhalation,
Long- Term ( 6 months), Carcinogenicity in Mice:
Kidney
effects in females including tubular dilatation, chronic glomerulonephritis,
and hyaline casts at the LOAEL of 10.06
/ 10.28 mg/kg/day, M/F.
Ref: June 4, 2002. Federal Register. Cyhalofop-butyl;
5-Year Time-Limited Pesticide Tolerance. Final Rule.
http://www.fluorideaction.org/pesticides/cyhalofop-butyl.fr.june4.02.htm
Liver
(click
on for all fluorinated pesticides)
5. Subchronic and chronic
toxicity, and oncogenicity. Cyhalofop- butyl caused increases
in liver and kidney weights, microscopic
hepatocellular hypertrophy, renal
tubular microscopic effects, and distended gallbladders when given
at sufficiently high dose levels to the appropriate species for
13 weeks. Similar increases in liver and
kidney weights, hepatocellular hypertrophy, and renal effects
were also observed in chronic toxicity studies in rodents. In
addition, mice had liver inflammation (microgranulomas).
Chronic toxicity in dogs was limited to decreased body weight
and the occurrence of concretions in the gallbladder. Using the
Guidelines for Carcinogen Risk Assessment published September
24, 1986 (51 FR 33992), it is proposed that cyhalofop and cyhalofop-butyl
be classified as Group E for carcinogenicity (no evidence of carcinogenicity)
based on the results of carcinogenicity studies in two species.
Dow AgroSciences LLC believes that there was no evidence of carcinogenicity
in an 18-mouse feeding study and a 24-month rat feeding study
at all dosages tested.
Ref: Federal Register. April 25, 2001. [PF-1009;
FRL-6774-7]
http://www.fluoridealert.org/pesticides/Cyhalofop-butyl.FR.Apr.2001.htm
SUBCHRONIC STUDIES
(90-day feeding study) 52840-028; 172924; "XRD-537 NBU: Four-Week
and 13-Week Dietary Toxicity Studies in Sprague-Dawley Rats";
(R.A. Corley, K.T. Haut, and L.G. Lomax; The Toxicology Research
Laboratory, Health and Environmental Sciences, The Dow Chemical
Company, Midland, MI; Study ID. DR-0298- 8876-003; 3/7/91); Two
studies were performed at the same time. In the first study, five
Sprague-Dawley rats/sex/group (unless otherwise noted) were dosed
orally in the diet with 0, 25, 400 (M only), 800 (F only) or 1600
mg/kg b. wt./day of XRD-537 NBU (n-butyl ester; AGR 276541, purity:
98.2%) for 4 weeks. In the second study, 10 rats/sex/group (unless
otherwise noted) were dosed orally in the diet with 0, 3 (M only),
10 (F only), 25 (M only), 100, 400 or 800 (F only) mg/kg b.wt./day
of the test material for 13 weeks. In the 4-week study, mean body
weight for the animals in the 1600 mg/kg group was less than that
of the control. The target organ was the
liver with increased liver weight
noted for the 25 mg/kg males and the 800 mg/kg females
(p<0.05). Diffuse hepatocellular hypertrophy
was noted for the males at 25 mg/kg and above and for the
females at 800 mg/kg and above. In the 13-week study, the mean
body weight of the females in the 800 mg/kg group was lower than
that of the control (p<0.05). However, there was no apparent treatment-related
effects upon food consumption. For the males in the 100 and 400
mg/kg groups, the mean red blood count, hemoglobin concentration
and hematocrit were less than that of the control (p<0.05). The
serum alkaline phosphate activity was increased for both sexes
at 100 mg/kg and above (p<0.05). The mean plasma albumin levels
for males in the 400 mg/kg and the females in the 400 and 800
mg/kg groups were increased (p<0.05) in contrast to the globulin
levels which were lower for 400 mg/kg males and the 800 mg/kg
females (p<0.05). The liver was the target
organ with increased liver weights noted for the 100 mg/kg groups
and above (p<0.05). Multifocal and/or diffuse hepatocellular hypertrophy
was reported for the males in the 25 mg/kg group and above
and for the females in the 100 mg/kg group and above (p<0.05).
No adverse effect indicated; Reported NOEL: (4-week study) (M)
< 25 mg/kg/day (based upon increased mean
liver weight and the incidence of diffuse hepatocellular hypertrophy
in the 25 mg/kg/day treatment group), (F) 25 mg/kg/day (based
upon increased mean liver weight and incidence
of diffuse hepatocellular hypertrophy in the 800 mg/kg/day
treatment group; (13-week study) (M) 3 mg/kg/day (based upon the
incidence of multifocal hepatocellular hypertrophy in the 25 mg/kg/day
treatment group, (F) 10 mg/kg/day (based upon the increased mean
liver weight and incidence of multifocal
and diffuse heptocellular hypertrophy at 100 mg/kg); Study
unacceptable. possibly upgradeable with the submission of the
concentrations of the test material in the dietary preparations
and a calculation of the actual doses which the study animals
received. (Moore, 11/16/00)
Ref: Summary of Toxicological Data for Cyhalofop-butyl.
California EPA, Department of Pesticide Regulation, Medical Toxicology
Branch. February 16, 2001.
http://www.fluorideaction.org/pesticides/cyhalofop.butyl.ca.tox.2001.pdf
A
February
17, 2005,
check at the Code
of Federal Regulations for Cyhalofop-butyl, cyhalofop acid
and the di-acid metabolite: this herbicide is permitted
in or on 2 food
commodities in the United States.
The
following list identifies these crops for which EPA has
set pesticide tolerances.
|
[Code
of Federal Regulations]
[Title 40, Volume 22]
[Revised as of July 1, 2004]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR180.576]
[Page 511]
TITLE 40--PROTECTION OF ENVIRONMENT
CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
PART 180_TOLERANCES AND EXEMPTIONS FROM TOLERANCES FOR PESTICIDE
CHEMICALS
IN FOOD--Table of Contents
Subpart C_Specific Tolerances
Sec. 180.576 Cyhalofop-butyl; tolerances for residues.
(a) General. Time-limited tolerances
are established for combined
residues of cyhalofop (cyhalofop-butyl, R-(+)-n-butyl-2-(4(4-cyano-2-
fluorophenoxy)-phenoxy)propionate, plus
cyhalofop acid, R-(+)-2-(4(4-
cyano-2-fluorophenoxy)-phenoxy)propionic acid) and
the di-acid
metabolite, (2R)-4-[4-(1-carboxyethoxy)phenoxy]-3-fluorobenzoic
acid,
from the application of the herbicide cyhalofop-butyl in or
on the
following raw agricultural commodities: |
Commodity |
As
of
September 26,
2003
PPM |
As
of
February 17,
2005
PPM |
Expiration/
Revocation Date |
Rice, grain
|
0.03 |
0.03 |
6/1/2007
|
Rice, straw |
8.0 |
8.0 |
6/1/2007
|
(b)
Section 18 emergency exemptions. [Reserved]
(c) Tolerances with regional registrations. [Reserved]
(d) Indirect or inadvertent residues. [Reserved] |
|