See - brief information on the thyroid
The Endocrine System

Illustration by K. Born in Our Stolen Future
(1996)
by Theo Colborn, Dianne Dumanoski and JP Myers
The
use of high doses increases the likelihood that potentially
significant toxic effects will be identified. Findings of
adverse effects in any one species do not necessarily indicate
such effects might be generated in humans. From a conservative
risk assessment perspective however, adverse findings in
animal species are assumed to represent potential effects
in humans, unless convincing evidence of species specificity
is available.
--
Food and Agricultural Organization of the United Nations
|
Note:
This is not an exhaustive list.
When time allows more information will be added.
Haloxyfop
- Herbicide - CAS No. 69806-34-4
The subchronic toxicity
of haloxyfop (2-(4-((3-chloro-5-(trifluoromethyl)-2- pyridinyl)oxy)phenoxy)propanoic
acid) herbicide, a peroxisome proliferator,
was evaluated in rats, mice, dogs and monkeys. Male rats given
0.2 or 2.0 mg/kg/day and female rats given 2.0 mg/kg/day in feed
for 16 weeks had peroxisome associated hepatocellular hypertrophy.
Male and female rats given 2.0 mg/kg/day for 37 weeks also had
increased renal tubular pigment. Mice given 2.0 mg/kg/day in feed
for 13 weeks had peroxisome associated hepatocellular hypertrophy.
Dogs fed 20 mg/kg/day and monkeys gavaged with 30 mg/kg/day for
13 weeks had hepatocellular hypertrophy, decreased
size of thyroid follicles, and decreased
red blood cell counts and serum cholesterol. Hepatocellular effects
in dogs and monkeys were not associated with peroxisome proliferation.
No-observed effect levels were between 0.02 and 0.2 mg/kg/day
for rats, 0.2 mg/kg/day for mice, and 2 mg/kg/day for dogs and
monkeys. There were no effects on reproduction in rats at dose
levels up to 1.0 mg/kg/day or evidence of teratogenicity in rats
or rabbits at dose levels up to 7.5 or 20 mg/kg/day, respectively.
Ref:
Subchronic and reproductive toxicity and teratology of haloxyfop
herbicide. Authors: Quast JF Yano BL Dietz FK Marler RM Hayes
WC. Source: Toxicologist 1990 Feb;10(1):175. As cited at Toxnet.
Haloxyfop-methyl
- Herbicide - CAS No. 69806-40-2
-- 2) 13-Week Feeding
- dog: Dietary levels tested: 0, 2, 5, and 20 mg/kg/day; Beagle
dogs (4/sex/dose level) were administered
haloxyfop-methyl in the diet for 13 weeks. A statistically significant
decrease in serum cholesterol values was reported for males fed
2 mg/kg/day. A statistically significant decrease in serum cholesterol
values was reported for males and females fed 5 mg/kg/day.
A significant decrease in male and
female triiodothyronine and free thyroxine
values was accompanied by a significant decrease in male and female
relative thyroid/parathyroid weights. Hepatic peroxisomal
fatty acid beta-oxidation was increased in males and females fed
5 mg/kg/day. Histological changes reported at this level were
hepatocellular enlargement with increased
glycogen content, decrease in follicular size and hypertrophy
of the follicular epithelial cells of the thyroid, and decrease
size of the testicular tubules. The LEL for systemic toxicity
is 2 mg/kg/day, the lowest dose tested, based on decreases in
serum cholesterol values in males. A NOEL for systemic toxicity
was not established; core grade minimum (Dow Chemical Co., 1987a)
Ref:
Health Assessment. US EPA Integrated Risk Information System (IRIS).
http://www.fluoridealert.org/pesticides/haloxyfop.methyl.iris.htm
Isoxaflutole
- Herbicide - CAS No. 141112-29-0
Likely
to be carcinogenic to Humans. Statistically
significant increases in liver tumors
in both sexes of CD-1 mice & Sprague-Dawley rats; statistically
significant increases in thyroid
tumors in male rats.
Ref: April
26, 2006 . Chemicals Evaluated for Carcinogenic Potential by the
Office of Pesticide Programs. From: Jess Rowland, Chief Science
Information Management Branch Health Effect Division (7509C) Office
of Pesticide Programs, USEPA.
http://www.fluorideaction.org/pesticides/pesticides.cancer.potential.2006.pdf
-- Isoxaflutole demonstrates
developmental toxicity and has been classified as a Group
B2 carcinogen (probable human carcinogen).
-- In a combined chronic toxicity/carcinogenicity study in rats,
evidence of systemic toxicity was observed at 500 mg/kg/day and
included: abnormal gait, limited use of limbs, lower
body weight gains and food consumption, decreased food efficiency
during the first 14 weeks of the study, elevated cholesterol levels
throughout the 104-week study, increased absolute and relative
liver weights, and thyroid
hyperplasia.
Increased incidence of periacinar hepatocytic
hypertrophy, portal tract (senile) bile duct changes, focal cystic
degeneration of the liver was observed in males at 20 mg/kg/day
and greater, females at 500 mg/kg/day. Eye opacity, gross necropsy
changes in eyes, corneal lesions, degeneration of sciatic nerve
and thigh muscles was observed in males at 20 mg/kg/day and higher
doses and in females at 500 mg/kg/day. The chronic LOAEL is 20
mg/kg/day based on liver,
thyroid, ocular, and nervous system toxicity
in males and liver toxicity in females. The chronic NOEL
is 2.0 mg/kg/day.
-- Under the conditions of this study, isoxaflutole induced
benign and malignant tumors of the liver in both sexes at 500
mg/kg/day hepatocellular adenomas and hepatocellular carcinomas.
Combined incidences of liver adenoma/carcinoma in males and females
showed animals bearing carcinomas in the majority. Thyroid
follicular adenomas occurred with increased frequency in 500 mg/kg/day
males. The
tumor incidences exceeded the historical incidence of these tumors
for this strain in the laboratory. The study demonstrated
that isoxaflutole is carcinogenic to rats at a dose of 500 mg/kg/day.
The chemical was administered at a dose sufficient to test its
carcinogenic potential. At 500 mg/kg/day, there were alterations
in most of the parameters measured including clinical signs of
toxicity, body weight gain, food consumption, food conversion
efficiency, and clinical as well as post-mortem pathology. Thyroid
stimulating hormone (TSH) was not measured in this study. However,
in a separate special study investigating the mechanism of action
of isoxaflutole on the thyroid, tested
at the same doses as this study, TSH was indirectly measured since
there was a significant reduction in T4
level and thyroid gland weights were significantly increased.
These results were sufficient to support the hypothesis that isoxaflutole
may have induced thyroid tumors in male
rats through a disruption in the thyroid-pituitary hormonal feedback
mechanisms.
Ref: US EPA. Pesticide Fact Sheet. Isoxaflutole
Reason for Issuance: Conditional Registration Date Issued: September
15, 1998. http://www.epa.gov/opprd001/factsheets/isoxaflutole.pdf
Lactofen
- Herbicide - CAS No. 77501-63-4
Dog chronic toxicity LOAEL = 3.96 mg/kg/day based
on increased incidence of
proteinaceous casts in the kidneys,
and statistically significant increases
in the absolute weights of the thyroid and adrenal glands in males.
Ref:
Sept 24, 2004. Lactofen. Pesticide Tolerance. Final Rule. Federal
Register.
http://www.fluorideaction.org/pesticides/lactofen.fr.sept.24.2004.htm
Lambda-cyhalothrin
-
see Cyhalothrin,
lambda
Norflurazon
- Herbicide - CAS No. 27314-13-2
Congestion of the liver,
hepatocyte swelling and increased liver weights, and increase
in colloid vacuole in the thyroid
were observed in dogs fed 450 ppm (10.25 mg/kg/day) norflurazon
for 6 months. The NOEL was 150 ppm (3.75 mg/kg/day). An oral RfD
of 0.04 mg/ kg/day has been determined. Increased relative liver
weight and hypertrophy of the thyroid
with depletion of colloid were seen in rats fed 2,500 ppm (125
mg/kg/day) norflurazon for 90 days. The NOEL was 500 ppm (25 mg/kg/day).
Hepatic hyperplasia and hypertrophy and increased relative liver
weight were noted in a 28-day feeding study in rats. The LOEL
was 1,000 ppm (50 mg/kg/day) and the NOEL was 500 ppm (25 mg/kg/
day). Increased relative liver weight and diffuse and smooth granular
livers were seen in a 28-day feeding study in mice. The LOEL was
2,520 ppm (328 mg/kg/day) and the NOEL was 420 ppm (55 mg/kg/day).
EPA believes that there is sufficient evidence for listing norflurazon
on EPCRA section 313 pursuant to EPCRA section 313(d)(2)(B) based
on the available hepatic and thyroid toxicity
data.
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 nine-month oral
toxicity study (MRID 00091056) was conducted using the F generation
of rats from a two-year carcinogenicity study (MRID 00082019).
In this study, rats were given technical norflurazon in the diet
at dose levels of 0, 125, 250, or 500 ppm (0, 6.25, 12.5, and
25 mg/kg/day) for 39 weeks... At 500 ppm... Thyroid
weight was decreased in males by approximately
30% vs control,
while
thyroid weight was increased in females between 11-47% vs control.
Gonadal
weight (left gonad) was increased in female rats by 30%.
At 250
ppm, thyroid weight was decreased by 30% in male rats, but was
increased by 11-29% in female rats.
However, there were no reported microscopic alterations in this
organ at any dose level tested. Gonadal
weight in female rats was increased by 17% vs. control.
The systemic NOEL was determined to be 250 ppm (12.5 mg/kg/day)
in both sexes. The systemic LEL was determined to be 500 ppm (25
mg/kg/day) in both sexes, based on the dose-related increase in
liver weight in male and female rats
at 39 weeks, the increase in gonad weight
of females, and the microscopic changes observed in
kidneys of
both sexes. Although
dramatic effects on thyroid weight were
observed at 250 ppm in both sexes, there were no data indicating
any alteration in histology of this organ. Thus, the weight change,
while indicative of an effect of norflurazon, is not supported
as a toxic effect based on available data (guideline: non-guideline
study; classified as core supplementary; MRID 00091056).
-- A chronic toxicity and carcinogenicity study was conducted
in Sprague-Dawley rats. In this study, technical norflurazon was
administered in the diet at dose levels of 0, 125, 375, or 1025
ppm (0, 6.25, 18.75, or 51.25 mg/kg/day) for 104 weeks... The
weight of the thyroid was also increased
at the 1025 ppm dose in male rats
at 104 weeks. An increased incidence of
hydronephrosis was observed in high dose male rats at 52
weeks vs control, while the incidence of
nephritis
was increased
in male rats (terminal sacrifice + dying on test) at the 1025
ppm dose. The incidence of tubular casts was increased in female
rats at the high dose in those rats surviving to study termination.
Other microscopic alterations observed at the high dose included
an increased incidence of parathyroid hyperplasia
(both sexes), hemosiderin pigment deposition in the spleen
(males only) and liver (both sexes), and endometritis
and squamous metaplasia of the uterus (females). The systemic
NOEL was determined to be 375 ppm (18.75 mg/kg/day) for both sexes.
The systemic LEL was determined to be 1025
ppm (51.25 mg/kg/day) in both sexes, based on the increased kidney
weight and accompanying microscopic pathologic changes, as well
as the increase in liver weight in male and female rats
and the increase in thyroid weight in males.
There was no evidence of carcinogenicity for norflurazon (guideline
83-5; MRIDs 00111617 and 00082019). As a result of the July 18,
1990 meeting of the OPP/Health Effects Division Carcinogenicity
Peer Review Committee, norflurazon was classified as a non quantifiable
Group C - possible human carcinogen - based
upon statistically significant pair-wise comparisons of the incidence
of liver adenomas and combined liver adenomas/ carcinomas as well
as statistically positive trends for these lesions in male CD-1
mice receiving 218.8 mg/kg/day norflurazon technical in
the diet for up to 104 weeks (MRID 00111649).
Ref: US EPA REREGISTRATION ELIGIBILITY DECISION
NORFLURAZON. LIST A. CASE 0229.
http://www.fluoridealert.org/PESTICIDES/Norflurazon.RED.EPA.pdf
Oxyfluorfen
- Herbicide - CAS No. 42874-03-3
Absolute and relative
thymus weights were decreased in mid-dose males (-14%/-10%)and
high-dose males (-32%/- 18%)...Vacuolation of the
adrenal cortex was present in high-dose females. Thymic atrophy
occurred in high-dose males and females.... Fine vacuolation of
adrenal glands (slight)and cortical atrophy of the thymus (slight)
were increased in high-dose males... Absolute and/or relative
organ weights in the high-dose groups that showed statistically
significant changes relative to
control weights (thyroid gland
in both sexes and kidney in females at 12 months and brain, pituitary,
and spleen in females sacrificed at 24 months) had no microscopic
correlates and are not considered toxicologically significant.
Ref: US EPA. Toxicology Chapter for RED.
August 8, 2001.
http://www.epa.gov/oppsrrd1/reregistration/oxyfluorfen/oxytoxchapter.pdf
Picolinafen
- Herbicide - CAS No. 137641-05-5
-- In a study in which
groups of two dogs per sex were fed picolinafen at dietary concentrations
of 0, 100, 1000, 2000, or 10000 ppm for 28 days, food consumption
and body weight gain were reduced at 10000 ppm...
Thyroid weight was increased in a dose-related manner in
dogs at all doses and thyroid enlargement
accompanied by histopathological changes was observed at ¥ 1000
ppm.
-- In groups of four dogs per sex fed picolinafen at dietary concentrations
of 0, 50, 500 or 2500 ppm for 90 days haemoglobin... Thyroids
were enlarged at 2500 ppm and thyroid weights were increased in
males at ¥500 ppm and in females at 2500 ppm... Follicular hypertrophy
was observed in the thyroid at 500
and 2500 ppm with hyperplasia at 2500 ppm. The NOEL in this study
was 50 ppm equal to 1.7 mg/kg bw/day in males and 1.8 mg/kg bw/day
in females.
-- In dogs fed picolinafen at dietary concentrations of 0, 50,
150 or 1500 ppm for 12 months body weight gains were decreased
in all groups of treated males... Enlarged
thyroids and increased thyroid
weights were observed at 1500 ppm. Increased follicular hypertrophy
in the thyroid was observed in both
sexes at 1500 ppm and hyperplasia in the
thyroid was observed in females at 1500 ppm. A NOEL could
not be established in this study since body weight gain was reduced
at all tested doses. The LOEL in this study was 50 ppm, equal
to 1.4 mg/kg bw/day in males and 1.6 mg/kg bw/day in females.
Ref: Public Release Summary on Evaluation
of the new active PICOLINAFEN in the products SNIPER HERBICIDE
& PARAGON HERBICIDE. Australia. National Registration Authority
for Agricultural and Veterinary Chemicals November 2000.
http://www.nra.gov.au/publications/prspic.pdf
-- Although findings
indicative of hemolytic anemia were noted in dogs following 90-day
and 1-year dietary administration, the main
target organ appeared to be the thyroid as indicated by
increased thyroid weight, diffuse hypertrophy of the thyroid follicular
epithelial cells, and scattered foci of thyroid follicular cell
hyperplasia, at 500 ppm (17.3 and 20.2 mg/kg bw/d and above
for males and females, respectively) and above following 90-day
dietary administration and at 1500 ppm (42.7 and 47.1 mg/kg bw/d
for males and females, respectively) and above following 1-year
dietary administration (the differences noted following 90-day
and 1-year dietary administration were due to dose selection).
Hormone levels (thyroxine, tri-iodothyronine and thyroid stimulating
hormone [TSH]) were not determined. Lower body weight and/or body-weight
gain were also noted in dogs at 2500 ppm (equal to 87.5 and 92.1
mg/kg bw/d for males and females, respectively) following 90-day
dietary administration and at 150 ppm (1.7 and 1.8 mg/kg bw/d
and above for males and females, respectively) and above following
1-year dietary administration. The NOAEL following 90-day dietary
administration was 50 ppm (equal to 1.7 and 1.8 mg/kg bw/d for
males and females, respectively). The NOAEL following 1-year dietary
administration was 50 ppm (equal to 1.4 and 1.6 mg/kg bw/d for
males and females, respectively).
-- The treatment-related findings noted in the
thyroid (increased thyroid weight, diffuse hypertrophy of the
thyroid follicular epithelial cells, and scattered foci of thyroid
follicular cell hyperplasia) in dogs following 90-day and
1-year dietary administration may be suggestive of a neurotoxicity
potential. Similar lesions were not observed in the rat (including
neonates) or mouse following subchronic or chronic dietary exposure
and there was no other evidence in any species tested to indicate
a neurotoxicity potential. Thyroid hormone (thyroxine, tri-iodothyronine,
and TSH) levels were not determined. Thyroid hormones are crucial
to normal growth and development in the central nervous system
and in the absence of the hormone, brain development can be retarded;
therefore, in the absence of thyroid hormone data and in the absence
of any human data, these lesions cannot
be disregarded and must be considered relevant to humans.
Ref:
February 17, 2003 - Canada. Picolinafen. Regulatory Note REG2003-02.
Alternative Strategies and Regulatory Affairs Division, Pest Management
Regulatory Agency.
http://www.fluorideaction.org/pesticides/picolinafen.canada.feb.2003.pdf
Occupational exposure will be predominately via the dermal route,
and of short- to intermediate-term duration. Although
a 4-week repeat dose dermal toxicity study is available, it is
not considered adequate for occupational and bystander risk assessment
since it does not adequately account for the treatment-related
findings noted in the thyroid in dogs following 90-day and 1-year
dietary administration. To account for these findings,
it is recommended that the dog 90 day dietary study be used for
the proposed exposure scenarios. The recommended NOAEL is 1.7
mg/kg bw/d. A safety factor of 100 to account for intraspecies
and interspecies variations is considered to be adequate; no additional
safety factors were used because there was an adequate MOE to
the NOAEL of 4.4 mg/kg bw/d for thyroid effects in the 1-year
dietary dog study.
Ref:
Nov 2005 - AC 900001 (Picolinafen). Proposed Regulatory Decision
Document. PRDD2005-5. Canadian
Pest Management Regulatory Agency (PMRA).
http://www.fluorideaction.org/pesticides/picolinafen.canada.nov05.pdf
Primisulfuron-methyl
- Fungicide,
Herbicide- CAS
No. 86209-51-0
-- Chronic toxicity:
Doses of 125 mg/kg/day administered in the diet to dogs over a
1-year period produced decreased body weight gain, anemia, increased
liver weight, and thyroid hyperplasia
(abnormal growth) [15]. Rats fed dietary doses of about
180 mg/kg/day over 90 days showed effects similar to those noted
in dogs, as well as spleen weight increases
[24]. In another study, doses of 480 mg/kg/day in rats over 18
months produced increased incidence of tooth disorders, chronic
nephritis (kidney damage), and testicular
atrophy [4]. In two 18-month studies in mice, testicular atrophy,
chronic nephritis, and increased tooth and bone disorders were
seen at doses of 180 mg/kg/day and 360 mg/kg/day, respectively
[4].
Ref: E X T O X N E T Extension Toxicology
Network Pesticide Information Profiles. Revised June 1996.
http://ace.ace.orst.edu/info/extoxnet/pips/primisul.htm
In a 90-day dog feeding
study, reduced thyroid weights accompanied
by colloid depletion and parafollicular hyperplasia and anemia
were observed at the LOEL of 25 mg/kg/day. The NOEL was 0.625
mg/kg/day. In a 1-year dog study, dietary administration of 250/125
mg/kg/day (LOEL: the dose was changed after week 10 in the study)
produced thyroid hyperplasia, anemia,
increased platelet levels, vacuolar changes, and increased absolute
and relative liver weights. The NOEL was 25 mg/kg/day. In an 18-month
study in mice, dietary administration of 1.7 mg/kg/day produced
increased absolute and relative liver weights in females. No NOEL
was established. Based on this study, an oral RfD of 0.006 mg/kg/day
was derived. In a 2-year mouse study, increases in absolute and
relative liver weights were observed at 408 mg/kg/day in males
and 1.7 mg/kg/day in females. The systemic LOEL and NOEL in males
was 408 mg/kg/day and 40.2 mg/kg/day, respectively. The systemic
LOEL in females was 1.7 mg/kg/day and a NOEL could not be established.
EPA believes that there is sufficient evidence for listing primisulfuron
on EPCRA section 313 pursuant to EPCRA section 313(d)(2)(B) based
on the available thyroid and liver
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.
Prodiamine
- Herbicide - CAS No. 29091-21-2
Group
C -- Possible Human Carcinogen. Thyroid
follicular cell neoplasia (M & F); Pancreatic
adenomas (F) in Sprague-Dawley rats. Fibrosarcomas;
CD-1 mice (M).
Ref: April
26, 2006 . Chemicals Evaluated for Carcinogenic Potential by the
Office of Pesticide Programs. From: Jess Rowland, Chief Science
Information Management Branch Health Effect Division (7509C) Office
of Pesticide Programs, USEPA.
http://www.fluorideaction.org/pesticides/pesticides.cancer.potential.2006.pdf
Abstract: Of 240 pesticides
screened for carcinogenicity by the U.S. Environmental Protection
Agency Office of Pesticide Programs, at least 24
(10%) produce thyroid follicular cell tumors in rodents.
Thirteen of the thyroid carcinogens also induce liver tumors,
mainly in mice, and 9 chemicals produce tumors at other sites.
Some mutagenic data are available on all 24 pesticides producing
thyroid tumors. Mutagenicity does not seem to be a major determinant
in thyroid carcinogenicity, except for possibly acetochlor; evidence
is less convincing for ethylene thiourea and etridiazole. Studies
on thyroid-pituitary functioning, including indications of thyroid
cell growth and/or changes in thyroxine, triiodothyronine, or
thyroid-stimulating hormone levels, are available on 19 pesticides.
No such antithyroid information is available for etridiazole,
N-octyl bicycloheptene dicarboximide, terbutryn, triadimefon,
and trifluralin. Of the studied chemicals, only bromacil lacks
antithyroid activity under study conditions. Intrathyroidal
and extrathyroidal sites of action are found: amitrole,
ethylene thiourea, and mancozeb are thyroid peroxidase inhibitors;
and acetochlor, clofentezine, fenbuconazole, fipronil, pendimethalin,
pentachloronitrobenzene, prodiamine,
pyrimethanil, and thiazopyr seem to enhance
the hepatic metabolism and excretion of thyroid hormone.
Thus, with 12 pesticides that mode of action judgments can be
made, 11 disrupt thyroid-pituitary homeostasis only; no chemical
is mutagenic only; and acetochlor may have both antithyroid and
some mutagenic activity. More information is needed to identify
other potential antithyroid modes of thyroid carcinogenic action.
Ref:
Hurley PM (1998). Mode
of carcinogenic action of pesticides inducing thyroid follicular
cell tumors in rodents. Environ Health Perspect; Aug;106(8):437-45.
--
Chronic/Subchronic Toxicity Studies. Prodiamine: Liver (alteration
and enlargement) and thyroid effects (hormone
imbalances) at high dose levels (rats); decreased body
weight gains.
-- Carcinogenic Potential. Prodiamine: Benign
thyroid tumors (rat). None observed (mouse).
-- Target Organs. Prodiamine: Liver
and Thyroid.
Ref: Material Safety Data Sheet for Barricade
65WG Herbicide. Novartis. February 28, 2000.
http://www.fluoridealert.org/pesticides/prodiamine.msds.2000.pdf
Sodium
bifluoride - Insecticide, Former US EPA
List 3 Inert -
CAS No.
1333-83-1
ENDOCRINE 0.2.16.2
CHRONIC EXPOSURE - Fluoride exposure can
cause moderate functional changes in the hypophysis-thyroid gland
system without any clinical manifestations. [FAN
note: Hypophysis = Pituitary gland]
Ref:
Hazardous Substances Data Bank for SODIUM HYDROGEN DIFLUORIDE
CASRN:
1333-83-1
http://www.fluorideaction.org/pesticides/sodium.bifluoride.toxnet.htm
Sulfuryl fluoride
- Fumigant
insecticide - CAS No. 2699-79-8
-- In subchronic (90-day) inhalation studies
- In
mice, follicular cell hypertrophy was noted in the thyroid
gland. Decreased body weights and body weight
gains were also observed in
rats, dogs and mice.
-- In chronic (1-2
year) inhalation studies - . In dogs
and mice, increased mortalities,
malacia and/or vacuolation in the white matter in the brain, histopathology
in the lungs, and follicular cell
hypertrophy in the thyroid gland were observed. Decreased
body weights and body weight gains were also noted in all three
species. No evidence of carcinogenicity was observed in either
the combined chronic toxicity/ carcinogenicity study in rats or
in the 18-month carcinogenicity study in mice.
Ref:
Federal Register: September 5, 2001 (Volume 66, Number 172). Sulfuryl
Fluoride; Proposed Pesticide Temporary Tolerances.
http://www.fluorideaction.org/pesticides/sulfuryl.flu.fr.sept.5.2001.htm
18-Month carcinogenicity NOAEL =
25/25 (M/F) mg/kg/day inhalation study--mouse
LOAEL = 101/101 (M/F) mg/kg/day based (870.4200) on for both M/F
cerebral vacuolation in brain, decreased body weight gain, follicular
hypertrophy in thyroid (M only), increased mortality (F
only), heart thrombus (F only), and lung congestion (F only).
No evidence of carcinogenicity in M or F.
Ref: January
23, 2004. Sulfuryl Fluoride; Pesticide Tolerance.
40 CFR Part 180 [OPP-2003-0373; FRL-7342-1]. Final Rule. Federal
Register
Tefluthrin
- Insecticide - CAS No. 79538-32-2
-- 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
Tetraconazole
- Fungicide - CAS No. 112281-77-3
Chronic & Carcinogenicity Studies.
Rats received 0, 10, 80, 640 or 1280 ppm (the last dose to males
only) of tetraconazole in the diet for 2 years... Cystic follicular
hyperplasia and follicular epithelial hypertrophy
were increased in the thyroid of males at 1280 ppm. Tumor
incidences were not increased by treatment. The NOEL was 10 ppm
(0.4 mg/kg bw/day).
Ref: August
2005 - Evaluation of Tetraconazole in the product Domark 40ME
Fungicide. Australian Pesticides and Veterinary Medicines Authority.
http://www.fluorideaction.org/pesticides/tetraconazole.2005.report.australia.pdf
-- The class of compounds
(triazoles) to which tetraconazole belongs is known to induce
liver microsomal enzymes. The follicular
cell hypertrophy and cystic follicular hyperplasia of the thyroid
seen in male rats at 1,280 ppm are also likely to be linked
to the hepatic changes. Compounds such as phenobarbital are also
known to induce thyroid changes in rats due to increased hepatic
clearance of thyroxin, mediated by hepatic enzyme induction.
Ref: Federal Register: October 14, 1999.
Notice of Filing Pesticide Petitions to Establish a Tolerance
for Certain Pesticide Chemicals in or on Food. PP 9F5066, 9F6023,
and 7E4830. http://www.fluoridealert.org/pesticides/tetraconazole.fr.oct14.1999.htm
Thiazopyr
- Herbicide - CAS No. 117718-60-2
Group
C -- Possible Human Carcinogen. Statistically
significant increase in thyroid follicular
cell tumors (M). Increases in renal
tubular adenomas (M & F); however statistically significant
positive trend in F only; Sprague-Dawley rats.
Ref: April
26, 2006 . Chemicals Evaluated for Carcinogenic Potential by the
Office of Pesticide Programs. From: Jess Rowland, Chief Science
Information Management Branch Health Effect Division (7509C) Office
of Pesticide Programs, USEPA.
http://www.fluorideaction.org/pesticides/pesticides.cancer.potential.2006.pdf
-- There was no evidence
of carcinogenic effects in an 18-month chronic/oncogenicity study
in mice at dose levels up to and including 800 ppm (216 mg/kg/day).
In rats, an increased incidence of thyroid
follicular tumors in males at the two highest doses, 1000
(44.2 mg/kg/day, males) and 3000 ppm, (136.4 mg/kg/day) was observed,
and there was a low incidence of renal tubular
adenoma at the high dose only in females. The
thyroid tumors were determined in three special thyroid function
studies to be secondary to a disturbance of thyroid/pituitary
homeostasis and were attributed to a hormonally-mediated mechanism
for thyroid tumor induction. The effects were dose-responsive
and with the exception of thyroid weight,
all effects were completely reversible when thiazopyr was removed
from the diet. Based on limited evidence for carcinogenicity,
thiazopyr is classified as Category C, possible human carcinogen,
by the USEPA Health Effects Division Carcinogenicity Peer Review
Committee. A NOEL of 4.4 mg/kg/day and a Margin of Exposure
approach were selected for use in carcinogenicity risk assessment.
-- Thiazopyr technical produced organ toxicity following multiple
exposures at high doses. The primary target organs for thiazopyr
toxicity in the rat, mouse and dog were the
liver, thyroid, kidney
and blood, with the liver
being the most sensitive indicator of toxicity. In chronic
dietary feeding studies, the dog was the most sensitive species.
An RfD for thiazopyr of 0.008 mg/kg/day was established by the
RfD Committee of the USEPA Health Effects Division, based on the
NOEL of 0.8 mg a.i./kg/day (20 ppm) from the chronic dog study
and a 100-fold safety factor to account for intraspecies extrapolation
and intraspecies variability.
-- 90-day Oral (Rat): NOEL (systemic) =100 ppm (6.60 mg /kg/day
and 7.99 mg/kg/day for males and females, respectively). The LOEL
was 1000 ppm (68 - 79 mg/kg/day in males and females, respectively)
based on increased liver,
thyroid and kidney weights,
changes in clinical chemistry and hematological parameters and
on gross and microscopic changes observed
in the liver and thyroid at
does levels of 68 mg/kg/day and higher. At the 201 mg/kg/day dose
diffused thyroid follicular cell hypertrophy/
hyperplasia was observed.
-- 90-day Oral (Dog): NOEL (systemic) =10 ppm. (0.2 mg/kg/day(m);
0.3 mg/kg/day(f)), based on decreased body
weight gain and increased SGPT levels at 3 and 6 m/kg/day for
males and females, respectively and above; decreased total protein
and albumin concentration and albumin/globulin ratio, increased
AP, hepatocytic hypertrophy, oval cell proliferation and
increased hepatocytic fatty content at 35 mg/kg/day and above;
and decreased calcium concentration which is thought to be related
to hypoalbuminemia, decreased cholesterol and triglyceride concentrations,
slightly increased GGT and SGPT, follicular
hyperplasia of thyroid, increased colloid content in follicles
and increased relative thyroid weight
at 175 mg/kg/day.
-- A 3 week dermal study in rabbits at 0, 100, 500 and 1000 mg/kg/day
with a NOEL of 100 mg/kg/day. The effects were increased mean
absolute and relative kidney weights and minimal multifocal or
periportal hypatocyte vacuolation.
-- A two year rat carcinogenicity study at doses of 0, 0.04, 4.4,
44.2 or 136.4 mg/kg/day (Males) 0, 0.06, 0.6, 5.6, 56.3 or 177.1
mg/kg/day (female) with a NOEL of 4.4 mg/kg/day. The effects were
protruding eyes, evidence of mild anemia,
increased GGT and cholesterol, increased absolute and relative
liver, kidney and thyroid weights
and significant increase in microscopic
lesions in the liver (hypertrophy and vacuolar changes), kidney
(nephropathy) and thyroid (hypertrophy
and hyperplasia); decreased mean
body weight and body weight gain and food consumption. A
statistically significant increase in thyroid
follicular cell adenomas/cystadenomas were observed in males at
44.2 and 136.4 mg/kg/day. A nonsignificant
increase in renal tubular adenomas in high-dose females was considered
to be equivocal.
-- The EPA Health Effects Division Carcinogenicity Peer Review
Committee classified thiazopyr as a Group
C, possible human carcinogen and recommended that for the
purpose of risk characterization a Margin of Exposure (M.O.E.)
approach should be used in evaluation of the consequences of human
exposure.
-- Special mechanistic studies for mode of toxic action on thyroid
function. The results of three studies on the effects of
thiazopyr on thyroid function and
mechanisms involved in the disposition of T4 in rats were reviewed.
These studies are described below:
---- a. Thiazopyr was administered through the diet at 0 and 150
mg/kg/day rats to determine the subchronic effect on hormone level
and other biochemical endpoints. Animals were assayed at 7, 14,
28, 56 or 90 days. Significant decreases
in body weight gain were observed at 90 days. Early in
the study the treated rats showed increases in TSH
(ranging from 133 to 200% of controls) and decreases
in T4 (ranging from 43% to 76% of controls). In addition
there were increases in liver and thyroid
weights and increases in thyroid
follicular cell hypertrophy/hyperplasia. Reverse T3 was
increased at 28 days, and T3 was either not affected or increased.
There were indications of increases in hepatic
UDPGT activity and significant increases
in T4 UDPGT activity. Hepatic 5'-monodeiodinase activity
was either not affected or decreased. The effects observed in
this study were supportive of the theory that thiazopyr may induce
thyroid tumors through a disruption in the
thyroid-pituitary hormonal feedback mechanisms.
---- b. A second study on the effects of thiazopyr on the biochemical
mechanisms of thyroid toxicity in rats at doses of 0, 0.5, 1.5,
5, 15, 50 or 150 mg/kg/day was conducted. Dose response effects
on various biochemical parameters were observed. Two groups of
the rats in the study were observed for reversibility of effects
observed up to 56 and 112 days. Doses at 15, 50 and 150 mg/kg/day
significantly increased the liver weights.
Thyroid weights were increased at
doses of 50 and 150 mg/kg/day. There were no significant effect
on body weight or body weight gains during the study. The T4 UDPGT
levels were increased by 117 and 376% above controls at the 50
and 150 mg/kg/day dosages. Effects of 150 mg/kg/day were increases
in T3, TSH and rT3 serum concentrations, and increased incidence
of follicular cell hypertrophy/hyperplasia
at the 150 mg/kg/day dose. A NOEL of 1.5 mg/kg/day was determined
based on liver weight increases. Thyroid
weight was the only parameter that did not return to those similar
to the controls. At the 56 and 112 day recovery periods the thyroid
weights were 120 and 123% of control values, respectively.
---- c. A third thyroid function study on the biochemical mechanisms
involved with disposition of T4 in rats fed dosages of 0 and 150
mg/kg/day for 56 days was conducted. Rats feed thiazopyr had increase
T4 UDPGT activity and total deiodinase
activity in their livers. There was also a two-fold increase in
mixed function oxidase enzyme activity.
-- Results of the three studies suggest that increased glucuronidation,
deiodination of T4 and T3, and increased
rate of clearance of T4 from the
blood and excretion of the hormone and its metabolites in the
bile could significantly reduce the level of circulating T4
in the male rat. Results of these studies support the hypothesis
tht thiazopyr may induce thyroid tumors
through a disruption of the thyroid-pituitary hormonal feedback
mechanism circulating T4 in the male rat.
Ref: US EPA. Pesticide Fact Sheet. Thiazopyr
Reason for Issuance: Registration of a New Chemical Date Issued:
February 20, l997.
http://www.epa.gov/opprd001/factsheets/thiazopyr.pdf
Tolylfluanid
- Fungicide - CAS No. 731-27-1
Likely to
be Carcinogenic to Humans. Thyroid
tumors
in male and female Wistar rats. Linear low-dose extrapolation
approach recommended.
Ref: April
26, 2006 . Chemicals Evaluated for Carcinogenic Potential by the
Office of Pesticide Programs. From: Jess Rowland, Chief Science
Information Management Branch Health Effect Division (7509C) Office
of Pesticide Programs, USEPA.
http://www.fluorideaction.org/pesticides/pesticides.cancer.potential.2006.pdf
Toxicity - General:
The skeletal system
(bones and teeth), liver and
thyroid were identified
as target organs in the animal studies.
Ref:
US EPA Pesticide Fact Sheet. Reason for Issuance: Import Tolerance.
September 2002.
http://www.fluorideaction.org/pesticides/tolylfluanid.epa.facts.2002.pdf
-- Cancer Classification:
``Likely to be carcinogenic to humans''
by the oral route, based
on thyroid tumors in high-dose male and
female rats. The FQPA SF Committee
further recommended a linear low-dose extrapolation approach for
the quantification of human cancer risk based on the thyroid tumors
in rats. Q1*
= 1.59 x 10-\3\ based upon
male rat thyroid adenomas and/or carcinomas combined.
-- Combined chronic toxicity/carcinogenicity rodents (rat): NOAEL
= 18.1/21.1 mg/ kg/day (M/F); LOAEL = 90.1/105.2 mg/ kg/day (M/F),
based on skeletal changes. Evidence
of thyroid follicular cell adenomas and/or carcinomas in high-
dose males and females.
-- Combined chronic toxicity/carcinogenicity rodents (rat): NOAEL
= 20/20 mg/kg/ day (M/F); LOAEL = 80/110 mg/kg/day (M/F),
based on bone hyperostosis in males and
females Evidence of thyroid follicular cell adenomas and/or
carcinomas in high- dose males and females.
-- Non-guideline (rat) thyroid function: Thyroid-stimulating
hormone
levels significantly
increased (168-425%) in high-dose males and females. Slightly
increased T3 levels in males rats above 119.3 mg/ kg/day.
--
Metabolite Non-guideline (mice).
In
vitro investigation
of TTCA goitrogenic
properties.
Tolylfluanid's
metabolite TTCA was shown to reversibly inhibit thyroid peroxidase
(TPO)- mediated reactions involved with the initial stages of
thyroid hormone synthesis... TTCA, unlike tolylfluanid, behaves
as a goitrogenic compound with a potency approximately equal to
propylthiouracil (PTU), a known thionamide inhibitor of initial
thyroid hormone synthesis.
Ref: Federal Register: September 25, 2002.
Tolylfluanid; Pesticide Tolerance. Final Rule. Federal Register.
http://www.fluorideaction.org/pesticides/tolylfluanid.fr.sept25.2002.htm
Transfluthrin
- Insecticide - CAS
No. 118712-89-3
3.2.2.1 Oral Route
... At 250 mg kg and 28 d, in both sexes, there were absolute
and body weight relative increases in liver
(15-20%) and kidney weights (~ 10%). In males absolute
and body weight relative thyroid weight
increases were also observed (20-25%). These changes were reversed
by 56 d... In all males at 500 ppm and
5000 ppm and in three males treated
for 19 w the thyroid follicular epithelium was hypertrophied and
colloid was depleted. The NOEL for this study was 10 ppm
(0.85 mg kg d) based on the effects at and above 50 ppm (4.0 mg
kg d) of significant increase in fluoride
levels in teeth and bone in both sexes and evidence of
kidney toxicity (based on absolute and relative weight increases
in both sexes and urinary protein content increases in
males). In addition liver and
thyroid toxicity was noted at 500 and 5000 pm.
-- In 90 d study Beagles (4/sex/group)
were administered transfluthrin (94.5%0 pure via their food at
nominal concentrations of 0, 50, 350 or 2500 ppm. Haematological
and urine examinations were carried out on all grops pre study
and at 3, 6 and 13 w. Ophthalmological examinations were carried
out pre study, 6 and 13 w, and hearing tests were carried out
pre study and 13 w. ... The haematological and
urine examinations showed no treatment related changes. The clinical
chemistry examination indicated treatment related effects on the
liver. At 2500 ppm increases in cholesterol levels were noted
in both sexes which increased with time (~ 35-70% in males and
~ 60-80% in females over `- 13 w). In addition at 13 w plasma
lipid and triglyceride levels were increased in both sexes (~
110-120%). N-demethylase activity was increased in both sexes
at 2500 ppm (~ 35%). At 13 w the examination also noted
a decrease in thyroxine levels in females
(~ 45%) and a non-significant decrease in triiodothyronine
(~ 40%) at 2500 ppm. At necropsy, gross pathological examination
noted no treatment related changes. At 2500 ppm
relative (to the brain) liver weights increased in both sexes
(~ 30% in males and ~50% in females) and thyroid
weight increased non-significantly in females (~ 70%)...
-- 3.3.3.4 Summary ... Following
oral administratin the major target organ in the rat and dog was
the liver, with evidence of kidney toxicity also seen in the rat.
Fluoride determinations were undertaken in the rat only and showed
evidence of accumulation in teeth and bone from 50 ppm
(4 mg kg d). In the rat, mortalities and body tremors
were seen at 250 mg kg d following gavage dosing. ... In
the liver, absolute and relative organ weight increases (recovering
following cessation of treatment) together with clinical chemistry
and histopathological evidence of hepatocyte hypertrophy were
observed from 500 ppm and at 250 mg kd d. There was also evidence
of kidney toxicity from 50 ppm (absolute and body weight relative
increases in kidney weight in both sexes ... In the thyroid,
hypertrophy of the thyroid follicular epithelium and colloid depletion
was reported from 500 ppm. The NOEl was 10 ppm (0.85 kg d).
-- 3.2.4 Carcinogenicity
Studies. ... In a combined chronic toxicity and carcinogenicity
study, groups of 60 Wistar rats (strain
Bor:WISW (SPF Cpb) of both sexes were administered transfluthrin
(94.5-95% pure) in the diet at concentrations of 0, 20, 200 or
2000 ppm for 109 weeks. In addition, groups of 10 male and 10
female rats were treated identically for full interim necropsy
at 52 weeks... At 52 weeks at 2000 ppm in males there was an increased
incidence of "cuboidal follicular epithelium"
in the thyroid (in 7/10 animals) and at the end of the
study, a slight increase in thryoid follicular
cell hyperplasia in males and females at 200 and 2000 ppm
(incidences 0, 0, 3. 3 and 0. 0, 1, 2 at 0, 20, 200 and 2000 ppm).
... There is no evidence of a treatment related increase in thyroid
tumour incidence and the low numbers of
hepatocellular adenoma/carcinoma are considered to be within the
historical control range. Benign adrenal tumours seen in males
are within the control ranges for Wistar rats. There is a low
but increased incidence of urinary bladder tumours at 2000 ppm
in both sexes. The mechanixm is considered to be non genotoxic
given the increased incidence of urinary epithelial hyperplasia
in both sexes, at this dose. ... A NOEL for non-neoplastic findings
is 20 ppm ( 1 mg kg d, based on effects in the kidney (increased
organ weight, pigment deposition and glomerulonephrosis) at 200
ppm and above).
-- 3.2.4 Carcinogenicity Studies. The two available studies, in
the rate and mouse both combine chronic toxicity and carcinogenicity...
Single incidences of tumours occurring in treated groups but not
controls were reported in the kidneys, ovaries, brain, parathyroid
and skeletal muscle. Neither these, nor the occasional incidences
of systemic tumors presented in Table 3.3 were considered to be
treatment related (page 23).
Ref: Evaluation on: Transfluthrin Use as
a Public Hygiene Insecticide. September 1997. Prepared by: the
UK Health and Safety Executive, Biocides & Pesticides Assessment
Unit, Magdalen House, Stanley Precinct, Bootle, Merseyside L20
3QZ. Available from: Department for Environment, Food and Rural
Affairs, Pesticides Safety Directorate, Mallard House, Kings Pool,
3 Peasholme Green, York YO1 7PX. UK. Also at http://www.pesticides.gov.uk/citizen/evaluations/165_confirm-box.htm
• Note:
This was transcribed from the copy available on the web. While
one can easily read this report on the web, the report is inaccessible,
or locked, to any attempt to copy it. Any errors are mine. EC.
Trifluralin
- Herbicide - CAS No. 1582-09-8
Group
C -- Possible Human Carcinogen. Thyroid
(follicular celladenomas & carcinomas); Neoplasms of the
renal pelvis (M);
Benign urinary bladder tumors (F); Fischer 344 rats.
Ref: April
26, 2006 . Chemicals Evaluated for Carcinogenic Potential by the
Office of Pesticide Programs. From: Jess Rowland, Chief Science
Information Management Branch Health Effect Division (7509C) Office
of Pesticide Programs, USEPA.
http://www.fluorideaction.org/pesticides/pesticides.cancer.potential.2006.pdf
Long term toxicity and carcinogenicity (Annex IIA, point 5.5).
Carcinogenicity. Evidence
of carcinogenic potential in Fischer 344 rat,
(tumour formation in various tissues, i.e.
kidney, urinary bladder,
thyroid, Leydig cell). The mechanism of tumour formation
is not identified. R40. (page
46)
Ref: March 14, 2005. European
Food Safety Authority: Conclusion regarding the
peer review of the pesticide risk assessment of the active substance
trifluralin. EFSA Scientific Report (2005) 28, 1-77.
http://www.fluoridealert.org/pesticides/trifluralin.eu.long.2005.pdf
-- EPA
has classified trifluralin as a Group C (possible human) carcinogen.
Classification is based on the induction of urinary tract tumors
(renal pelvis carcinomas and urinary bladder papillomas) and thyroid
tumors (adenomas/carcinomas combined) in one rat study.
Ref: March 2000.
Public Health Assessment Cenex Supply and Marketing, Inc. Quincy,
Washington. CERCLIS # WAD058619255.
Draft for Public Comment.. Prepared by: Washington State Department
of Health Under Cooperative Agreement with the Agency for Toxic
Substances and Disease Registry. Also available at http://www.doh.wa.gov/ehp/oehas/Cenex%20PHA%20Draft%20Public%20Review.pdf
Cancer Classification
The OPP Carcinogenicity Peer Review Committee evaluated all the
available carcinogenicity data on trifluralin (April 4, 1986),
and it concluded that there is limited evidence of carcinogenicity
in male and female rats based upon an increase in combined malignant
and benign urinary bladder tumors in females,
renal pelvis carcinomas in male rats, and thyroid
gland follicular cell tumors (adenomas plus carcinomas combined)
in males. Trifluralin has been classified as a Group
"C" possible human carcinogen with a Q of 0.0077 (mg/kg/day)
. The upper bound 1 * -1 dietary cancer risk is is approximately
1.0 x 10 . -6
Ref: Reregistration Eligibility Decision
(RED) Trifluralin. US EPA, Office of Prevention, Pesticides and
Toxic Substances. EPA 738-R-95-040. April 1996.
http://www.fluoridealert.org/pesticides/trifluralin.red.1996.epa.pdf
Preliminary
evaluation of carcinogenicity and exposure data: There
is a MEDIUM level of carcinogenicity concern over trifluralin.
Concern is due to dose-dependent increases in the incidences of
tumors of the transitional epithelium of
the bladder and renal pelvis in male and female F344 rats,
and significant increases in thyroid follicular tumors in males.
Ref: PRIORITIZED
CANDIDATE CHEMICALS UNDER CONSIDERATION FOR CARCINOGENICITY EVALUATION:
BATCH #1. Office of Environmental Health Hazard Assessment, California
Environmental Protection Agency May 1997.
http://www.oehha.ca.gov/prop65/pdf/batch1.pdf
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