Return
to Tefluthrin Index Page
Activity:
Insecticide
(pyrethroid)
Structure:
Adverse
Effects:
Ataxia
Blood
Body Weight Decrease
Bone
Brain
Cholesterol
Endocrine: Thyroid
Endocrine:
Uterus
Heart
Liver
Tremors
Environmental
As
of February 16, 2005, this insecticide and its metabolite
is permitted in or on corn
in the United States - see list at bottom of page.
|
Table
6-1. Trends of National Pyrethroid Use
September
2001. Draft
Toxicological Profile for Pyrethrins and Pyrethroids.
US Department of Health and Human Services. Public Health
Service Agency for Toxic Substances and Disease Registry.
Organofluorine pyrethroids discussed in the Profile: Bifenthrin
(Type 1), Cyfluthrin (Type 2), Cyhalothrin (Type 2), Flucythrinate
(Type 2), Flumethrin (Type 2), Fluvalinate (Type 2), Tefluthrin
(Type 1).
Note from EC: The following 4 organofluorine pesticides
were included in a list of 11 pesticides.
|
Pyrethroid |
Amounts
applied
(pounds) 1992 |
Amounts
applied
(pounds) 1992 |
Percent
change |
Bifenthrin |
116,716 |
110,246 |
-5 |
Cyfluthrin |
124,360 |
177,782 |
+43 |
lambda
Cyhalothrin |
205,329 |
321,284 |
+57 |
Tefluthrin |
238,429 |
576,865 |
+142 |
Ataxia
(click on for all fluorinated pesticides)
-- In a chronic toxicity
study, dogs were dosed at dose levels of 0, 0.1, 0.5, and 2 mg/kg/day
for 12 months. The LOEL for this chronic study is 2.0 mg/kg/day
based on the increased incidence of ataxia
in both sexes at the high-dose. The NOEL is 0.5 mg/kg/day.
-- Toxicological Endpoints 1. Acute toxicity. For acute dietary
risk assessment, EPA recommends use of a NOEL of 0.5 mg/kg/day
based on increased incidence of tremors
and ataxia in both sexes of dogs at 2.0 mg/kg/day (LOEL)
on day 1 of the study from the 1 year oral chronic toxicity study
in dogs.
-- Toxicological Endpoints 2. Short - and intermediate - term
toxicity. For short- and intermediate term MOE's, EPA recommends
use of a NOEL of 0.5 mg/kg/day based on increased incidence of
tremors and ataxia in both sexes
of dogs at 2.0 mg/kg/day (LOEL) from the one year oral toxicity
study in dogs and use of a dermal absorption rate of 25%. A dermal
absorption rate of 25% was recommended based on the weight-of-the-evidence
available for structurally related pyrethroids.
-- Chronic toxicity. EPA has established the RfD for tefluthrin
at 0.005 milligrams/kilogram/day (mg/kg/day). This RfD is based
on increased incidence of tremors and ataxia
in both sexes of dogs in a chronic toxicity study and an uncertainty
factor of 100 to account for both interspecies extrapolation and
intraspecies variability.
Ref: Federal Register: November 26, 1997.
Tefluthrin; Pesticide Tolerance. Final Rule. http://www.fluoridealert.org/pesticides/Tefluthrin.FR.Nov.1997.htm
Blood
(click on for all fluorinated pesticides)
In a 3-month rat study,
dietary administration of 10 mg/kg/day produced plasma,
red blood cell, and brain cholinesterase inhibition.
The NOEL was 5 mg/kg/day. In a 6-month dog study, dietary administration
of 10 mg/kg/day (LOEL) produced plasma cholinesterase
inhibition. The NOEL was 1 mg/kg/day. In a 21-day rat dietary
study, administration of 20 mg/kg/day (LOEL for females) produced
decreased platelet counts, increased white
blood cell, lymphocyte, and neutrophil counts in males
and females. The NOEL for females was 5 mg/kg/day... EPA believes
that there is sufficient evidence for listing tefluthrin on EPCRA
section 313 pursuant to EPCRA section 313(d)(2)(B) based on the
available developmental, neurological, hepatic, and hematological
toxicity data for this chemical.
Ref:
USEPA/OPP. Support Document for the Addition of Chemicals from
Federal Insecticide, Fungicide, Rodenticide Act (FIFRA) Active
Ingredients to EPCRA Section 313. U. S. Environmental Protection
Agency, Washington, DC (1993). As cited by US EPA in: Federal
Register: January 12, 1994. Part IV. 40
Body
Weight Decrease (click
on for all fluorinated pesticides)
Reproductive and developmental
toxicity. In a rat developmental study, [[Page 50363]] delayed
ossification was noted in the highest dose group (5 mg/kg/day),
along with significant maternal toxicity
(decreased body weight (bwt)). The developmental no observed
effect level (NOEL) for this study was established at 3 mg/kg/day.
Ref: Federal Register: September 25, 1997
[Page 50337-50367]. Notice of Filing of Pesticide Petitions.
http://www.fluoridealert.org/pesticides/Bifenthrin.FR.Sept.25.1997.htm
Bone
(click on for all fluorinated pesticides)
Reproductive and developmental
toxicity. In a rat developmental study, [[Page 50363]] delayed
ossification was noted in the highest dose group (5 mg/kg/day),
along with significant maternal toxicity (decreased body weight
(bwt)). The developmental no observed effect level (NOEL) for
this study was established at 3 mg/kg/day.
Ref: Federal Register: September 25, 1997
[Page 50337-50367]. Notice of Filing of Pesticide Petitions.
http://www.fluoridealert.org/pesticides/Bifenthrin.FR.Sept.25.1997.htm
-- In a developmental
toxicity study, rats were dosed at 0, 1, 3, or 5 mg/kg/day from
days 7 through 16 of gestation. The maternal LOEL is 3 mg/kg/day,
based on treatment-related decrease body weight gains during dosing.
The maternal NOEL is 1 mg/kg/day. Developmental toxicity was demonstrated
at 5 mg/kg/day as an increase in the fetal incidence of bilaterally
unossified calcanea (92.9% vs. 87.5% in controls, p<0.05;
litter incidence was not shown) and a slight increase in the pes
score (3.05 vs. 2.96 in controls) indicating slight inhibition
of ossification at these sites. There
were no treatment-related effects on the number, growth, and survival
of the young in utero. In addition, the inter-group differences
in the mean numbers of corpora lutea,
implantations, pre- and post- implantation deaths, live fetuses,
proportion of male fetuses, and fetal
weights were not remarkable. The developmental LOEL is 5 mg/kg/day,
based on inhibited ossification.
The developmental NOEL is 3 mg/kg/day.
-- In a developmental toxicity study, rabbits were dosed at 0,
3, 6, or 12 mg/kg/day from days 7 through 19 of gestation. The
maternal LOEL is 3 mg/kg/day, based on treatment-related clinical
signs of toxicity (tremors). The
maternal NOEL is <3 mg/kg/day. There was no developmental toxicity
demonstrated at any dose level. There were no treatment-related
effects on in utero survival and growth or on litter size and
sex ratio of the fetuses. The skeletal
variant
data showed significant
(p<0.01 or 0.05) increases in incidence
of extra thoracic ribs and 27 pre-sacral vertebrae among fetuses
in the dosed groups; however, when the litter was used
as the unit for comparison, the incidences of these respective
variants were comparable between all groups. The incidences of
these variants were not biologically significant. The NOEL for
developmental toxicity is 12 mg/kg/day. The developmental LOEL
was not observed.
Ref: Federal Register: November 26, 1997.
Tefluthrin; Pesticide Tolerance. Final Rule. http://www.fluoridealert.org/pesticides/Tefluthrin.FR.Nov.1997.htm
Brain
(click on for all fluorinated pesticides)
In a 3-month rat study,
dietary administration of 10 mg/kg/day produced plasma, red blood
cell, and brain cholinesterase inhibition.
The NOEL was 5 mg/kg/day. In a 6-month dog study, dietary administration
of 10 mg/kg/day (LOEL) produced plasma cholinesterase inhibition.
The NOEL was 1 mg/kg/day.
Ref:
USEPA/OPP. Support Document for the Addition of Chemicals from
Federal Insecticide, Fungicide, Rodenticide Act (FIFRA) Active
Ingredients to EPCRA Section 313. U. S. Environmental Protection
Agency, Washington, DC (1993). As cited by US EPA in: Federal
Register: January 12, 1994. Part IV. 40 CFR Part 372. Addition
of Certain Chemicals; Toxic Chemical Release Reporting; Community
Right-to-Know; Proposed Rule.
Cholesterol
(click
on for all fluorinated pesticides)
In a subchronic oral
toxicity study, rats were dosed at 0, 50, 150, or 350 ppm (2.5,
7.5, or 17.5 mg/kg/day) for 90 days. The LOEL for this 90-day
feeding study is 150 ppm (equivalent to approximately 7.5 mg/kg/day)
based on changes in hemoglobin, cholesterol,
and liver weight in the mid-dose animals. The NOEL is 50 ppm (equivalent
to approximately 2.5 mg/kg/day).
Ref: Federal Register: November 26, 1997.
Tefluthrin; Pesticide Tolerance. Final Rule. http://www.fluoridealert.org/pesticides/Tefluthrin.FR.Nov.1997.htm
Heart
(click
on for all fluorinated pesticides)
Abstract. This report
describes for the first time a novel anionic background current
(I(AB)) identified in guinea-pig isolated ventricular myocytes.
It also shows that I(AB) has both novel and differential pharmacology
from other (cardiac) chloride currents. Using the whole-cell patch-clamp
technique and external anion substitution, I(AB) was found to
be outwardly rectifying and highly permeable to NO(-)(3), with
a relative permeability sequence of NO(-)(3) > I(-) > Cl(-). I(AB)
was not blocked by 50 microM DIDS, by hypertonic external solution,
or by the nonselective protein kinase inhibitor H7-DHC. Exposure
to the pyrethroid agent tefluthrin (10 microM) increased the current
density of I(AB) significantly at positive voltages (P < 0.05),
but had no significant effect on other cardiac chloride currents.
We conclude that I(AB) possesses a distinct pharmacology and does
not fall into the three major classes of cardiac chloride conductance
commonly reported. (C)2002 Elsevier Science (USA).
Ref: Borg JJ et al. (2002). Tefluthrin
modulates a novel anionic background conductance (I(AB)) in guinea-pig
ventricular myocytes. Biochem
Biophys Res Commun. Mar 22;292(1):208-15.
Abstract: Pyrethroid
insecticides are known to modify neuronal sodium channels, inducing
persistent, steady-state sodium current at depolarized membrane
potentials. Cardiac myocytes are also rich in sodium channels
but comparatively little is known about the effect of pyrethroids
on the heart, or on the cardiac sodium channel isoform. In the
present study therefore, we determined the actions of type I and
type II pyrethroids against rat and guinea pig ventricular myocytes
under current and voltage clamp, and on isolated perfused rat
hearts. In myocytes, tefluthrin
(type I) and fenpropathrin and alpha-cypermethrin (type
II) prolonged action potentials and evoked
afterdepolarizations. The time course of sodium current
(I(Na)) was also prolonged by these compounds. Pyrethroids delayed
I(Na) inactivation, when measured under selective conditions as
current sensitive to 30 microM tetrodotoxin, by increasing the
proportion of slowly inactivating current at the expense of fast
inactivating current. Further experiments, focusing on fenpropathrin,
revealed that its effects on I(Na) inactivation time course were
dose-dependent, and the Na(+) "window-current" was increased in
its presence. In unstimulated, isolated hearts perfused with the
same pyrethroids, the variability in contraction amplitude increased
due to variations in the intervals between heartbeats. These potentially
arrhythmogenic changes are consistent with the effects observed
at the cellular level. The type I pyrethroid tetramethrin had
little effect in any of the preparations. These
findings suggest that some pyrethroids possess considerable mammalian
cardiac arrhythmogenic potential, the manifestation of
which in vivo may depend on the route of exposure.
Discussion from
full paper: The principal findings of the present study
at the cellular level are that the type I pyrethroid tefluthrin
and the type II pyrethroids fenpropathrin and -cypermethrin
1) prolonged ventricular action potentials
and evoked afterdepolarizations;
2) modified the time course of INa by altering
the relative proportions of fast and slowly inactivating current;
and
3) altered the voltage dependence of INa.
At the whole heart level, these effects corresponded with a pyrethroid-induced
increase in the variability of contractile force, suggestive of
proarrhythmic activity. Several aspects of these findings
merit detailed consideration.
Ref: Spencer CI et al. (2001). Actions
of pyrethroid insecticides on sodium currents, action potentials,
and contractile rhythm in isolated mammalian ventricular myocytes
and perfused hearts. J Pharmacol
Exp Ther. 2001 Sep;298(3):1067-82. Erratum
in: J Pharmacol Exp Ther 2001 Oct;299(1):399.
Full free report available at
http://jpet.aspetjournals.org/cgi/content/full/298/3/1067
Endocrine:
Thyroid (click
on for all fluorinated pesticides)
-- In a subchronic
oral toxicity study, dogs were dosed at 0, 0.1, 0.5, or 1.5 mg/kg/day
for 90 days. The LOEL for this 90-day oral toxicity study is 1.5
mg/kg/day based on thyroid changes,
and increased levels of plasma triglycerides and aspartate transaminase
observed at the high-dose. The NOEL is 0.5 mg/kg/day.
-- Endocrine Disrupter Effects. EPA
is required to develop a screening program to determine whether
certain substances (including all pesticides and inerts) ``may
have an effect in humans that is similar to an effect produced
by a naturally occurring estrogen, or such other endocrine effect...''
The Agency is currently working with interested stakeholders,
including other government agencies, public interest groups, industry
and research scientists in developing a screening and testing
program and a priority setting scheme to implement this program.
Congress has allowed 3 years from the passage of FQPA (August
3, 1999) to implement this program. At that time, EPA may require
further testing of this active ingredient and end use products
for endocrine disrupter effects.
Ref: Federal Register: November 26, 1997.
Tefluthrin; Pesticide Tolerance. Final Rule. http://www.fluoridealert.org/pesticides/Tefluthrin.FR.Nov.1997.htm
Endocrine:
Uterus
(click on for
all fluorinated pesticides)
-- In a chronic/oncogenicity
study, mice were dosed at 0, 25, 100, or 400 ppm (actual dose
levels were equivalent to 3.4, 13.5, or 54.4 mg/kg/day) for 104
weeks. The chronic LOEL is 13.5 mg/kg based on hemangiomatous
changes of the uterus and
liver necrosis
observed in the mid- and high-dose females. The chronic
NOEL is 3.4 mg/kg. Under the conditions of this study, there was
no evidence of carcinogenic potential.
-- In a developmental toxicity study, rats were dosed at 0, 1,
3, or 5 mg/kg/day from days 7 through 16 of gestation. The maternal
LOEL is 3 mg/kg/day, based on treatment-related decrease body
weight gains during dosing. The maternal NOEL is 1 mg/kg/day.
Developmental toxicity was demonstrated at 5 mg/kg/day as an increase
in the fetal incidence of bilaterally unossified
calcanea (92.9% vs. 87.5% in controls, p<0.05; litter incidence
was not shown) and a slight increase in the pes score (3.05 vs.
2.96 in controls) indicating slight inhibition of ossification
at these sites. There were no treatment-related effects
on the number, growth, and survival of the young in utero. In
addition, the inter-group differences in the mean numbers of corpora
lutea, implantations, pre- and post- implantation deaths,
live fetuses, proportion of male fetuses,
and fetal weights were not remarkable. The developmental LOEL
is 5 mg/kg/day, based on inhibited ossification.
The developmental NOEL is 3 mg/kg/day.
Ref: Federal Register: November 26, 1997.
Tefluthrin; Pesticide Tolerance. Final Rule.
http://www.fluoridealert.org/pesticides/Tefluthrin.FR.Nov.1997.htm
Liver
(click on for
all fluorinated pesticides)
-- In a chronic/oncogenicity
study, mice were dosed at 0, 25, 100, or 400 ppm (actual dose
levels were equivalent to 3.4, 13.5, or 54.4 mg/kg/day) for 104
weeks. The chronic LOEL is 13.5 mg/kg based on hemangiomatous
changes of the uterus and
liver necrosis observed in the mid- and high-dose females.
The chronic NOEL is 3.4 mg/kg. Under the conditions of this study,
there was no evidence of carcinogenic potential.
Ref: Federal Register: November 26, 1997.
Tefluthrin; Pesticide Tolerance. Final Rule. http://www.fluoridealert.org/pesticides/Tefluthrin.FR.Nov.1997.htm
Tremors
(click on for
all fluorinated pesticides)
-- In a developmental
toxicity study, rabbits were dosed at 0, 3, 6, or 12 mg/kg/day
from days 7 through 19 of gestation. The maternal LOEL is 3 mg/kg/day,
based on treatment-related clinical signs of toxicity (tremors).
The maternal NOEL is <3 mg/kg/day. There was no developmental
toxicity demonstrated at any dose level. There were no treatment-related
effects on in utero survival and growth or on litter size and
sex ratio of the fetuses. The skeletal
variant
data showed significant (p<0.01 or 0.05) increases in incidence
of extra thoracic ribs and 27 pre-sacral vertebrae among fetuses
in the dosed
groups; however, when the litter was used as the unit for comparison,
the incidences of these respective variants were comparable between
all groups. The incidences of these variants were not biologically
significant. The NOEL for developmental toxicity is 12 mg/kg/day.
The developmental LOEL was not observed.
-- Toxicological Endpoints 1. Acute toxicity. For acute dietary
risk assessment, EPA recommends use of a NOEL of 0.5 mg/kg/day
based on increased incidence of tremors
and ataxia in both sexes of dogs at 2.0 mg/kg/day (LOEL) on day 1
of the study from the 1 year oral chronic toxicity study in dogs.
-- Toxicological Endpoints 2. Short - and intermediate - term
toxicity. For short- and intermediate term MOE's, EPA recommends
use of a NOEL of 0.5 mg/kg/day based on increased incidence of
tremors and ataxia
in both sexes of dogs at 2.0 mg/kg/day (LOEL) from the
one year oral toxicity study in dogs and use of a dermal absorption
rate of 25%. A dermal absorption rate of 25% was recommended based
on the weight-of-the-evidence available for structurally related
pyrethroids.
-- Chronic toxicity. EPA has established the RfD for tefluthrin
at 0.005 milligrams/kilogram/day (mg/kg/day). This RfD is based
on increased incidence of tremors and
ataxia in both sexes
of dogs in a chronic toxicity study and an uncertainty factor
of 100 to account for both interspecies extrapolation and intraspecies
variability.
Ref: Federal Register: November 26, 1997.
Tefluthrin; Pesticide Tolerance. Final Rule. http://www.fluoridealert.org/pesticides/Tefluthrin.FR.Nov.1997.htm
Environmental
(click
on for all fluorinated pesticides)
Aquatic
acute toxicity values for tefluthrin include a rainbow trout
96-hour LC 50 of 0.06 ppb,
a bluegill 96-hour LC50 of 0.13
ppb, a sheepshead minnow 96-hour LC50 of 0.13
ppb, a daphnid 48-hour EC50 of 0.07
ppb, and a mysid 96-hour EC 50 of 0.053
ppb. EPA believes that there is sufficient evidence
for listing teflurin on EPCRA section 313 pursuant to EPCRA
section 313(d)(2)(C) based on the available environmental
toxicity data for this chemical.
Ref: USEPA/OPP. Support
Document for the Addition of Chemicals from Federal Insecticide,
Fungicide, Rodenticide Act (FIFRA) Active Ingredients to
EPCRA Section 313. U. S. Environmental Protection Agency,
Washington, DC (1993). As cited by US EPA in: Federal
Register: January 12, 1994. Part IV. 40 CFR Part 372.
Addition of Certain Chemicals; Toxic Chemical Release Reporting;
Community Right-to-Know; Proposed Rule.
|
A
February
16, 2005,
check at the Code
of Federal Regulations for Teflulthrin (and its metabolite):
this insecticide is permitted in
or on 7 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: 40CFR180.440]
[Page 453]
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. 180.440 Tefluthrin; tolerances for residues.
(a) General. Tolerances are established for
the combined residues of
the insecticide tefluthrin (2,3,5,6 tetrafluroro-4-methylphenyl)methyl-
(1 alpha, 3 alpha)-(Z)-()-3(2-chloro-3,3,3-
trifluoro-1-propenyl)-2,2-diemthylcyclopropanecarboxylate)
and its
metabolite (Z)-3-(2-chloro-3,3,3-trifluroro-1-propenyl)-2,2-
dimethylcyclopropanecarboxylic acid in or on the following
commodities: |
Commodity |
As
of October 15,
2003
PPM |
As
of
February16,
2005
PPM |
Corn, field, fodder and forage, pop and sweet |
Not
Listed in this way |
0.06 |
Corn, fresh
(including sweet K and corn with husk removed 0.06 (CWHR) |
0.06 |
0.06 |
Corn, field,
grain and pop |
Not
Listed |
0.06 |
CORN,
FIELD, FORAGE |
0.06 |
Not
Listed in this way |
CORN,
FIELD, GRAIN |
0.06 |
Not
Listed in this way |
CORN,
FIELD, STOVER |
0.06 |
Not
Listed |
CORN,
POP, FODDER |
0.06 |
Not
Listed in this way |
CORN,
POP, FORAGE |
0.06 |
Not
Listed in this way |
CORN,
POP, GRAIN |
0.06 |
Not
Listed in this way |
CORN,
SWEET, FODDER |
0.06 |
Not
Listed in this way |
CORN,
SWEET, FORAGE |
0.06 |
Not
Listed in this way |
(b)
Section 18 emergency exemptions. [Reserved]
(c) Tolerances with regional registrations. [Reserved]
(d) Indirect or inadvertent residues. [Reserved] |
|