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.
Benfluralin
(Benefin) - Herbicide - CAS
No. 1861-40-1
208-079 167288, "Benefin:
Two-Year Dietary Chronic Toxicity/Oncogenicity Study in Fischer
344 Rats", (Michael R. Moore, Corning Hazleton Inc, Vienna,
VA., Laboratory ID # CHV 174-133, Sponsor Report # DR-0097-3397-005,
1 July 1996). Fifty CDF ¨ (F-344)CrlBR rats per sex per group
received benefin in the diet at 0, 10, 100, 2500, and 5000 ppm
for 2 yr. An additional 10 per sex per group at the same dose
levels were designated for 1-yr interim sacrifice. Estimated achieved
dosages were 0, 0.5, 5.4, 136, and 275 mg/kg/day in males, and
0, 0.7, 6.8, 168, and 331 mg/kg/day in females, respectively over
weeks 1-104....Tumor incidence: thyroid
follicular tumors (adenomas and carcinomas) increased in
males (incidences of 1, 1, 1, 7,
and 8 in controls through high dose, respectively) and females
(incidences of 0, 0, 1, 5, and 4)... Tumors are possible adverse
effects, which should be evaluated in perspective of the many
indications of excessive exposures at effective dose levels. Green
and Aldous, 4/11/00.
Ref: SUMMARY OF TOXICOLOGY DATA BENEFIN
Chemical Code # 000053. June 15, 1998 Revised: April 21, 2000.
California EPA, Department of Pesticide Regulation. Medical Toxicology
Branch.
http://www.fluoridealert.org/pesticides/benefin.ca.tox.rev.apr.2000.pdf
Benthiavalicarb-isopropyl
- Fungicide - CAS No. 177406-68-7
Likely
to be Carcinogenic to Humans. Malignant uterine tumors in female
Fisher 344 rats; Liver tumors in both sexes of B6C3F1 mice with
some supporting evidence of liver tumors in male rats;
Thyroid follicular cell tumors in
male B6C3F1 mice.
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
Bifenthrin
- Acaricide, Insecticide - CAS Numbers:
82657-04-3 (Cis); 83322-02-5 (Trans)
Limited data were available
regarding endocrine effects in animals following oral exposure
to pyrethroids. Serum levels of the thyroid
hormones T3 and T4 were significantly decreased in mice
administered fenvalerate at a dose level of 120 mg/kg/day for
15 days (Maiti and Kar 1998). Akhtar et al. (1996) reported similar
effects in rats administered bifenthrin or lambda-cyhalothrin
at daily oral dose levels of 0.5 mg/rat (approximately 0.75 mg/kg/day)
and 0.2 mg/rat (approximately 2 mg/kg/day), respectively, for
21 days. Lambda-cyhalothrin treated rats also exhibited a significantly
decreased serum T3/T4 ratio, relative to controls. In addition,
both bifenthrin and lambda-cyhalothrin treatment resulted in significantly
increased serum TSH levels, compared with control rats
(p 39)
Ref: 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.
Endocrine Disruption.
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.
Bifenthrin; Pesticide Tolerances. Final Rule.
http://www.fluoridealert.org/pesticides/bifenthrin.fr.nov.1997.htm
1-chloro-1,1-difluoroethane
-
Solvent, EPA List 2 Inert - CAS No. 75-68-3
Inhalation rat; lowest
published toxic concentration: 500 gm/m3/4 hour/4 week- intermittent;
Endocrine: Evidence of thyroid hypofunction.
Ref: Toksikologiya Novykh Promyshlennykh
Khimicheskikh Veshchestv. Toxicology of New Industrial Chemical
Substances. For English translation, see TNICS*. (Izdatel'stvo
Meditsina, Moscow, USSR) No.1- 1961-
As cited by The Registery of Toxic Effects
of Chemical Substances (RTECS)
http://www.cdc.gov/niosh/rtecs/kh74bad0.html#TPKVAL
Cloransulam-methyl
- Herbicide - CAS No. 147150-35-4
-- Cloransulam-methyl
was evaluated in 13-week dietary studies in rats, mice and dogs.
The primary target organs identified
in these studies were the kidneys (rat), the liver (mouse and
dog), and thyroid (rat). An NOEL
was not determined in the rat based upon minor histopathological
changes in the kidney (males) and the liver (females).
-- Chronic toxicity. In a 2-year combined chronic toxicity/ oncogenicity
study in the rat, the NOEL for chronic toxicity was 10 mg/ kg/day
based upon kidney and thyroid effects:
hypertrophy of collecting duct epithelial cells and vacuolation
consistent with fatty change in the proximal tubules of males
and females, and an increase in the incidence of mineralization
of the renal pelvis in males. Thyroid changes
were confined to the high dose males and consisted of hyperplasia
and hypertrophy of follicular epithelium.
Ref: Federal Register, March 26, 1997. DowElanco;
Pesticide Tolerance Petition Filing.
http://www.epa.gov/fedrgstr/EPA-PEST/1997/March/Day-26/p7496.htm
Cyhalothrin,
lambda -
Insecticide - CAS No. 91465-08-6
Limited data were available
regarding endocrine effects in animals following oral exposure
to pyrethroids. Serum levels of the thyroid
hormones T3 and T4 were significantly decreased in mice
administered fenvalerate at a dose level of 120 mg/kg/day for
15 days (Maiti and Kar 1998). Akhtar et al. (1996) reported similar
effects in rats administered bifenthrin or lambda-cyhalothrin
at daily oral dose levels of 0.5 mg/rat (approximately 0.75 mg/kg/day)
and 0.2 mg/rat (approximately 2 mg/kg/day), respectively, for
21 days. Lambda-cyhalothrin treated rats also exhibited a significantly
decreased serum T3/T4 ratio, relative to controls. In addition,
both bifenthrin and lambda-cyhalothrin treatment resulted in significantly
increased serum TSH levels, compared with control rats
(p 39)
Ref: 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.
Abstract (1996).
The effects of organochlorine, organophosphorus, and pyrethroid
insecticides on thyroid function were studied in rats. Young adult
male albino-rats were gavaged with 0.5 milligram (mg) per rat
heptachlor (76448), 0.60mg/rat benzene-hexachloride (58-89-9)
(BHC), 0.06mg/rat malathion (121-75-5), 0.2mg/rat O,S-dimethyl-phosphoramidothion
(10265-92-6) (Monitor), 0.5mg/rat bifenthrin
(82657-04-3) (Talstar), or 0.2mg/rat
lamdacyhalothrin (91465-08-6) (Karate)
daily for 21 days. They were then killed and weighed.
The serum was separated and analyzed for triiodothyronine (T3),
thyroxine (T4), and thyrotropin (TSH) using radioimmunoassays.
Except for Talstar, none of the insecticides affected body weight
gain. Talstar significantly decreased body weight gain. Heptachlor
and Monitor did not significantly affect serum T3, T4, and TSH
concentrations. Malathion, BHC, Karate, and Talstar significantly
decreased serum T3 and T4 concentrations and increased TSH concentrations.
Karate significantly decreased the T43 concentration.
None of the other insecticides altered the T4/T3 ratio.
The authors conclude that exposure to organochlorine,
organophosphorus, and pyrethroid insecticides for a relatively
short time can suppress thyroid secretory activity in young adult
rats. The decrease in body weight gain induced by Talstar
suggests that pyrethroid insecticides can inhibit growth rate.
Ref: Insecticide-Induced Changes in Secretory
Activity of the Thyroid Gland in Rats; by Akhtar N, Kayani SA,
Ahmad MM, Shahab M. Journal of Applied Toxicology, Vol. 16, No.
5, pages 397-400, 26 references, 1996.
Dichlofluanid
- Wood Preservative, Antifoulant, Fungicide, Acaricide -
CAS No. 1085-98-9
-- Professional
operators would not be expected to use products for prolonged
periods, therefore a value from a one year study would be suitable.
The other reported end points (thyroid tumours
and osteosclerosis) were associated with chronic exposure and much
higher doses. Acceptable risk assessments would require a safety
margin of about 100 over the NOAEL 2.5 mg kg -1 d -1 . Consequently
these would also offer a high margin of safety against the longer
term end points.
-- Carcinogenicity - The only carcinogenicity data relate to the
oral route of exposure, with studies performed in the rat and mouse.
No evidence of carcinogenic potential was observed in the mouse.
However, in the rat dichlofluanid was found to cause an increase
in the incidence of thyroid follicular cell
tumours at the highest dose level of 300-420 mg kg -1 d -1
. These tumours occurred at a single site, were of late onset and
generally benign pathology. Dichlofluanid has been thoroughly examined
for genotoxic potential and the available data indicate that dichlofluanid
was not an in vivo somatic cell or germ cell mutagen. The results
of the histopathological examination of the thyroid follicular cell
tumours are consistent with a non-genotoxic aetiology. Overall,
it can be concluded that dichlofluanid is a non-genotoxic
rat thyroid follicular cell carcinogen.
-- Dichlofluanid was found to cause an increase in the incidence
of thyroid tumours at highest dose
level of 300-420 mg kg -1 d -1 . These tumours occurred at a single
site, were of late onset and generally benign pathology. These pathology
findings are indicative of a non-genotoxic aetiology, consistent
with the overall conclusions from the genotoxicity studies. Rat
thyroid tumours arise as a secondary consequence of perturbations
in thyroid hormone homeostasis, leading to prolonged stimulation
of the thyroid gland via a positive feedback mechanism. Interspecies
comparisons of the relative sensitivities of thyroid hormone homeostasis
to disturbance by xenobiotics have shown that humans are markedly
less sensitive than rats. Overall, the ACP considered that the rat
thyroid follicular tumours would not be relevant to human health
if they were due to treatment-related hormone imbalance. However
it concluded that the in vitro studies did not convincingly demonstrate
inhibition of thyroid peroxidase. Whilst it seemed probable that
the mechanism was non-genotoxic, a more convincing explanation of
the mechanism was required.
-- One-year Study. A repeat-exposure study using Beagles (4/dose/sex)
is available; it was GLP and OECD Annex V compliant. Animals were
administered either vehicle or 2.5, 12.5 or 37.5/62.5 mg kg -1 d
-1 of dichlofluanid (90 % purity) in capsule form for one year.
The top dose was reduced at week 15 to 37.5 mg kg -1 d -1 because
of excessive toxicity. As a NOEL could not be established with the
initial dosing regime, a subsequent study was carried out in which
0 or 1.25 mg kg -1 d -1 dichlofluanid was used... Levels of the
thyroid hormones T3 (28 %) and T4 (37 %) were
elevated at study termination in animals receiving 37.5 mg
kg -1 d -1 . At necropsy, treatment-related pathology findings were
reported in males receiving 37.5 mg kg -1 d -1 . Externally one
animal was pale with discoloration of the kidney, liver and thyroid
which was also reduced in size. There were also non-significant
decreases in both absolute and relative thyroid
weights (39 % and 33 % respectively) and
testes weights (25 % and 15 % respectively). Two animals were found
to have bilateral testicular degeneration; no control animals were
reported with bilateral testicular degeneration. In females absolute
(15-60 %) and relative (25-150 %) ovary weights were increased in
all treatment groups. These increases were not dose related or statistically
significant... Minimal to severe thyroid
follicular cell degeneration was reported in all animals
from the top-dose group and one male from the middle-dose group.
The pituitary glands of several animals from the top-dose group
were found to have mild to severe hyperplasia (2 males and 2 females)
of large pale staining cells (basophils) in the pars distailis,
among pituitary basophils are the thyrotrophs... The thyroids
of males exhibited follicular cell hypertrophy; 0/50 (control),
2/10 (180 ppm), 1/10 (900 ppm) and 3/10 (4500 ppm)... In the thyroid
gland a statistically significant increase in the lesion described
as a focal follicular growth anomaly was established in both
sexes at the top dose. In males the following data were presented
: 1/50 (controls); 1/50 (180 ppm); 2/50 (900 ppm); and 3/49 (4500
ppm) and in females the data were : 0/50 (controls); 0/50 (180 ppm);
2/50 (900 ppm); and 4/49 (4500 ppm)... Two females sacrificed in
extremis were found to have thyroid follicular
cell carcinoma; one animal from each of the middle- and top-dose
groups. No statistically significant neoplastic events were reported.
However, a significant trend in the distribution
of thyroid adenomas was found in both sexes. A NOEL could
not be set due to the effects of excess fluoride and cranial osteosclerosis
at the lowest dose. The NOEL for neoplasms could be set at 900 ppm
(equivalent to 54.4 and 73.1 mg kg -1 d -1 for males and females
respectively) due to the increase in thyroid
tumours seen at the top dose. [Unpublished, 1993(b)]
Table
3.19 : Thyroid Hormone Levels
During The Study |
|
T3
(ng 100 ml -1 ) |
T4
(mg 100 ml -1 ) |
day |
0 |
4500
ppm |
% |
0 |
4500
ppm |
% |
7 |
55.2 |
45.7 |
-17.3 |
3.9 |
2.6 |
-32 |
21 |
52.9 |
45.3 |
14.5 |
4.2 |
3.5 |
-16 |
63 |
67.6 |
61.8 |
-8.7 |
5.7 |
5.1 |
-11.5 |
Table
3.20 : Thyroid Weights At Day
7 |
dose
ppm |
control |
150 |
500 |
1500 |
4500 |
weight
mg |
10 |
14 |
13 |
15 |
16 |
% increase |
- |
40 |
30 |
50 |
60 |
Ref:
January
2003 - Evaluation
on: Booster biocides in antifouling products. Full review of Dichlofluanid.
No. 206. Evaluation of Fully Approved or Provisionally Approved
Products. Prepared by : The 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 available at:
http://www.pesticides.gov.uk/citizen/Evaluations/206_dichlofluanid.pdf
In July 1998, discussing
this pesticide because it was an Accession Treaty priority for
A, the CMR Group agreed to classify it with Xn; R20 : Xi; R36
: R43 : N; R50-53. Symbols Xn and N. R-phrases 20-36-43-50/53.
S-phrases (2-)24-37-60-61. The proposal was sent to DG XI and
included in the 25th ATP. Regarding carcinogenicity, S argued
that the evidence was too weak for classification; tumour findings
were limited to high dose groups. B expressed doubts about the
aetiology of the rat thyroid tumours and, in relation to this,
UK noted that dichlofluanid was an inhibitor
of thyroid peroxidase. As the carcinogenicity issue was
not problematic under the Accession Treaty, the Group agreed to
conclude the present discussion with no classification for carcinogenicity.
However, dichlofluanid would be referred back to the Pesticides
Group for further consideration of carcinogenicity classification.
A explained that the thyroid tumours seen in rats were limited
to high dose groups and suggested classification with Carc Cat
3; R40. A also noted cranial effects in rodents that justify R48/22.
B, with support from IRL, P and E, considered the mechanism of
tumour induction to involve liver enzyme induction which did not
justify classification for carcino-genicity because it was not-relevant
to humans. UK noted, however, data suggesting
inhibition of thyroid peroxidase which would justify classification.
The Group agreed that more information was required from Industry
on these issues. A and UK offered to send their interpretation
of the data made available by Ind.
Ref: EUROPEAN COMMISSION DIRECTORATE GENERAL
JRC JOINT RESEARCH CENTRE Institute for Health and Consumer Protection
Unit: Toxicology and Chemical Substances European Chemicals Bureau
ECBI/12/99 Rev. 1 31.03.1999 SUMMARY
RECORD Meeting of the Commission Working Group on the Classification
and Labelling of Dangerous Substances Pesticides ECB Ispra, 18-20
November 1998
Dithiopyr
- Herbicide -
CAS No. 97886-45-8
The following results
were presented by a Monsanto scientist.
-- Thirteen-week Feeding Study in Rats.
Dithiopyr was administered via the diet to groups of
12 male and 12 female F-344 rats for 13 weeks at concentrations
of 0, 10, 100, 1000 and 5000 ppm.. Other findings included [no
concentrations listed] multiple organ weight effects,
thyroid follicular hypertrophy, adrenal
cortical hypertrophy, and pulmonary foam cell aggregation.
The subchronic NOEL in rats is considered to be 10 ppm. (The
Institute of Environmental Toxicology, 1988)
-- REPRODUCTION AND DEVELOPMENTAL TOXICITY STUDIES 1. Two-generation
Reproduction Study in Rats ¥Dithiopyr was administered via the
diet to groups of 24 male and 24 female S-D rats over 2 consecutive
generations at concentrations of 0, 25, 250 and 2500 ppm... Other
findings included [no concentrations listed]:
increased kidney weight, focal renal tubular atrophy, thyroid
follicular hypertrophy, and adrenal
cortical hypertrophy...
(The Institute of Environmental Toxicology, 1989)
Ref: Summary
of Toxicology Studies With Dithiopyr. Dennis P. WARD. Toxicology
Department, The Agricultural Grop, A Unit of Monsanto
Company (Received February 20, 1993). Also available at
http://wwwsoc.nii.ac.jp/pssj2/tec_info/dithiopy.pdf
Fipronil
- Acaricide,
Insecticide
- CAS No. 120068-37-3
Group
C -- Possible Human Carcinogen.
Thyroid follicular cell adenomas,
carcinomas & combined adenomas/carcinomas (M); thyroid follicular
cell adenomas and combined adenomas/carcinomas (F); Charles
River CD 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
•
Chronic toxicity. The
NOAEL for systemic toxicity in a 1-year feeding study in the
dog was 0.3 mg/kg/day in females
and 1 mg/kg/day in males, based on clinical signs of neurotoxicity
at 1 and 2 mg/kg/day in females and males, respectively.
The NOAEL for systemic toxicity in mice
was 0.5 ppm (0.06 mg/kg/day) based on
decreased body weight gain, decreased food conversion efficiency
in males, increased liver weights, and liver histopathology
at 10 ppm (1.3 mg/kg/day). Fipronil was not carcinogenic when
administrated to mice at dose levels up to 60 ppm. The NOAEL
in a 2-year dietary study in the
rat
was 0.5 ppm (0.019 and 0.025 mg/kg/day
for males and females, respectively) based on
clinical signs of toxicity and alterations
in clinical chemistry and thyroid parameters at 1.5 ppm
(0.059 and 0.078 mg/kg/day for males and
females, respectively).
• Cancer. The EPA's Health Effects
Division Carcinogenicity Peer Review Committee classified fipronil
in Group C - Possible Human Carcinogen,
based on thyroid tumors observed in rats at 300 ppm (HDT). Mechanistic
data indicate that these tumors are related to a disruption
in the thyroid-pituitary status and are specific to the rat.
In addition, there was no apparent concern
for mutagenic activity. Thus, it was recommended that RfD methodology,
i.e. non-linear or threshold, be used for the estimation of
human risk.
•
Reproductive and developmental toxicity.
In a two-generation rat study,
the NOEL for parental (systemic) toxicity
was 3 ppm (0.26 mg/kg/day for both sexes combined), based on
increased weight of the thyroid glands and
liver in males and females, decreased
weight of the pituitary gland in females, and an
increased incidence of follicular epithelial hypertrophy in
females at 30 ppm.
• Subchronic
toxicity. The
NOAEL for systemic toxicity in
rat was 5 ppm (0.35 mg/kg/day for
both sexes combined), based on alterations
in serum protein values and increased weight of the liver
and thyroid at 30 ppm (1.93 and 2.28 mg/kg/day for males and
females, respectively).
•
Endocrine disruption.
Data from the reproduction/ developmental
toxicity and short- and long-term repeated dose toxicity studies
with fipronil in the rat, rabbit, mouse, or dog, do not suggest
any endocrine disruption activity. This information is based
on the absence of any treatment-related effects from the histopathological
examination of reproductive organs as well as the absence of
possible effects on fertility, reproductive performance, or
any other aspect of reproductive function, or on growth and
development of the offspring. Evidence of offspring toxicity
was observed only in the presence of significant parental toxicity.
Fipronil disrupts the thyroid-pituitary
axis. However,
mechanistic studies have demonstrated that fipronil decreases
thyroid hormone levels in long-term studies via increased clearance,
rather than a direct effect on the thyroid. Concerns related
to long-term exposure of fipronil are addressed in human risk
estimates, as the chronic RfD (0.0002 mg/kg/day) is based on
endpoints that include thyroid hormone related effects in rats.
Ref:
August 24, 2005. Federal Register. Fipronil; Notice of Filing
a Pesticide Petition to Establish a Tolerance for a Certain
Pesticide Chemical in or on Food.
http://www.fluorideaction.org/pesticides/fipronil.fr.aug.24.2005.html
-- Reproduction
toxicity studies. The data base for reproductive toxicity
is considered complete. No additional studies are required at
this time. An acceptable two-generation reproduction study in
the rat using fipronil concluded that the LOEL for parental
(systemic) toxicity was 30 ppm (2.54 mg/kg/day for males and
2.74 mg/kg/day for females) based on increased weight of the
thyroid glands and liver in males and females; decreased
weight of the pituitary gland in females;
and an increased incidence of follicular epithelial hypertrophy
in the females. The NOEL for parental (systemic) toxicity
was 3 ppm (0.25 mg/ kg/day for males and 0.27 mg/kg/day for
females).
-- Carcinogenic classification and risk
quantification. EPA has classified this chemical as a
Group C--Possible Human Carcinogen, based on increases in
thyroid follicular-cell tumors in both sexes of the rat,
which were statistically significant
by both pair-wise and trend analyses. EPA has used the RfD methodology
to estimate human risk because the thyroid
tumors are due to a disruption in the thyroid-pituitary
status. There was no apparent concern for mutagenicity.
Ref: Federal Register: July 17, 1998.
Fipronil; Pesticide Tolerance. Final Rule.
http://www.fluoridealert.org/pesticides/fipronil.fr.july.17.1998.htm
Short-term toxicity.
-- 28 day dietary administration to rats.
Technical-grade fipronil (batch number IGB 464, purity, 93%)
was administered in the diet for four weeks to groups of five
Cr1:CD (SD) BR rats of each sex at concentrations of 25, 50,
100, 200, or 400 ppm, equal to 3.4, 6.9, 13, 24, or 45 mg/kg
bw per day for males and 3.5, 6.7, 13, 25, or 55 mg/kg bw per
day for females ... The target organs
were the liver and thyroid. Liver weights
were significantly increased in females at all doses and in
males at 200 and 400 ppm.
At necropsy, liver enlargement was observed in one or both sexes
starting at 50 ppm, and five males and three females at 400
pm had enlarged livers. Generalised hepatocyte enlargement was
observed microscopically in one male at 100 ppm, with increasing
incidence in animals of each sex at 200 and 400 ppm. Thyroid
follicular-cell hypertropy, generally of minimal severity but
of moderate severity in several males at 200 and 400 ppm, was
found in almost all treated animals but not in the controls.
(page 77)
-- 90-day dietary administration to rats. In a 13-week
study, rats (CD strain 10/sex/group) received dietary administration
of either 1, 5, 30 or 300 ppm fipronil (batch number PGS 963,
95.4% purity). This was equivalent to 0.07, 0.3, 2.1 or 22 mg/kg/d.
Doses were selected after a preliminary 14-d study showed deaths
(3/10 animals by 5 d) and muscular spasms at 30 mg/kg/d ...Absolute
thyroid weights were elevated (4.2-100% at 5-300 ppm) achieving
statistical significance at ≥30 ppm in females and at
300 ppm in males ... Histopathological
examination found treatment-related effects at the top dose
in the thyroids and livers of both sexes. Oil
red O staining revealed a high incidence of fat deposits in
all liver samples, including controls. A
statistically significant increase in panacinar hepatic fatty
vacuolation (controls 0/10 and 7/10 at 300 ppm) was reported
in males only. (page 78-79)
Ref:
April 204. Evaluation
on : Fipronil (Horticultural Uses).
No. 212.
UK Dept. for Environment, Food and Rural Affairs, Pesticides
Safety Directory.
http://www.fluorideaction.org/pesticides/fipronil.uk.report.apr.2004.pdf
--2 year dietary
study in rats. The carcinogenic potential of fipronil was determined
in a 2-year study carried out in the rat (CD strain). Animals
(50/sex/dose) received dietary administration of fipronil (batch
number PGS, 95.4% purity) at either 0.5, 1.5, 30 or 300 ppm;
equivalent to 0.02, 0.06, 1.3 and 13 mg/kg/d (males) and 0.03,
0.08, 1.6 and 17 mg/kg/d (females). (page 89)
-- At study termination histopathological findings were confined
to a statistically signifiicant increase in progressive senile
nephropathy in males and thyroid "follicular
cysts" (growth anomaly) at ≤30 ppm in females. (page
91)
-- A
significant increase was observed
in the incidences of thyroid follicular
cell adenomas and carcinomas in both sexes at the top dose (300
ppm); these exceeded the historical control incidence)
(page 95)
--
Reproductive Toxicity. Dietary
two-generation study in rats. In a two-generation study, CD
rats (30 animals/sex/dose) werre administered fipronil (batch
number PGS 974, 95.4% purity) in the diet at 3, 30 or 300 pm,
equivalent to 0.25, 2.5 or 26 mg/k/g bw per day for males and
0.27, 2.7 an 28 mg/kg bw per day for females. FO adults were
treated for 71 d before mating (1 male to 1 female pairing),
throughout the mating period (up to 21 d) and then throughout
gestation and lactation of the liter (F1a). Approximately 10
d after weaning (25 d post partum) of the F1a pups, animals
administered 3 or 30 ppm, as well as the control group, were
paired a second time to produce an F1b generation. The F1a litters
were randomly adjusted to 8 pups on 4 d post partum and, after
weaning, 30 animals/sex/dose were selected to form the F1 parents.
F1 parents were treated from weaning for a minimum of 10 weeks
and then paired (1 male to 1 female) to produce an F2 generation.
F1 adult treatment continued until F2 pups were weaned. ...
At necropsy no treatment -related macroscopic changes were noted
in adults or pups. In adults there were increases, often significant,
in absolute and relative liver (10-15% and 15-40% at 30 and
300 ppm) and thyroid weights (15-25% and 25-50% at 30 and 300
ppm). ... In F1 adults histopathological examination showed
a significant increaee in incidence of liver centrilobular fatty
vacuolation in females (1/29 in controls, 6/27 at 300 ppm) and
thyroid follicular hypertrophy in both
sexes (males 0/28 in controls, 9/30 at 300 ppm and females 0/29
in controls, 15/27 at 300 ppm). (pages 96-97)
Ref:
April 204. Evaluation
on : Fipronil (Horticultural Uses).
No. 212.
UK Dept. for Environment, Food and Rural Affairs, Pesticides
Safety Directory.
http://www.fluorideaction.org/pesticides/fipronil.uk.report.apr.2004.pdf
Excerpts
from: Table 5.17 Treatment -related
effects in the 24 month rat dietary study (page 92)
Ref:
April 204. Evaluation
on : Fipronil (Horticultural Uses).
No. 212.
UK Dept. for Environment, Food and Rural Affairs, Pesticides
Safety Directory.
http://www.fluorideaction.org/pesticides/fipronil.uk.report.apr.2004.pdf
|
|
-Males- |
-Females- |
ppm |
|
0 |
0.5 |
1.5 |
30 |
300 |
0 |
0.5 |
1.5 |
30 |
300 |
Mg/kg/bw |
|
0 |
0.02 |
0.06 |
1.3 |
13 |
0 |
0.03 |
0.08 |
1.6 |
17 |
|
Week |
|
|
|
|
|
|
|
|
|
|
T4 |
24 |
4.58 |
3.81* |
3.35*** |
2.43*** |
0.76*** |
2.85 |
3.09 |
3/49** |
2.98 |
1.46*** |
|
50 |
5.95 |
5.51 |
4.83** |
3.9*** |
23.07*** |
3.31 |
3.46 |
3.00 |
2.06*** |
1.38*** |
Organ
weights (g) and macro-patholgology |
|
89
weeks males, 91 weeks females |
Thyroid
weight |
89/91 |
0.042 |
0.051* |
0.053* |
0.063** |
0.094** |
0.036 |
0.038 |
0.036 |
0.044 |
0.072* |
*P<0.05,
**P<0.01, ***P<0.001 |
Effects
on thyroid hormone levels.
A further study was carried out to determine the effects of
fipronil on circulating TSH, T3 and T4 levels. The concentrations
of the three hormones were determined by radioimmunoassay. Animals
(10/sex/group, Crl:CD (SD)BR) received dietary administration
of fipronil (batch number PGS 963, 98.4% purity) for 28 d ...
The concentrations of thyroid hormones and TSH for males and
females respectively can be found in Tables 5.35 and 5.36. The
data presented are corrected means, to allow an analysis of
covariance to be carried out ... The NOAEL for this study was
1 ppm (equivalent to 0.1 mg/kg/d), based on increased thyroid
follicular epithelial height at ≥5 ppm in males. (pages
123-125)
Ref:
April 204. Evaluation
on : Fipronil (Horticultural Uses).
No. 212.
UK Dept. for Environment, Food and Rural Affairs, Pesticides
Safety Directory.
http://www.fluorideaction.org/pesticides/fipronil.uk.report.apr.2004.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:
Environ Health Perspect. 1998 Aug;106(8):437-45. Mode
of carcinogenic action of pesticides inducing thyroid follicular
cell tumors in rodents. By Hurley PM. Office of Prevention,
Pesticides and Toxic Substances, U.S. Environmental Protection
Agency, Washington, DC 20460 USA.
Fluazinam
- Fungicide
- CAS
No. 79622-59-6
Suggestive
Evidence of Carcinogenicity to Humans.
An increase in thyroid gland follicular
cell tumors in male rats, and an increased incidence of
hepatocellular tumors observed in the male mice was treatment-related.
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
-- Combined chronic
toxicity/carcinogenicity rats. NOAEL = Males: 0.38 mg/kg/day;
Females: 0.47 mg/kg/day LOAEL = Males: 3.8 mg/kg/day; Females:
4.9 mg/ kg/day based on liver toxicity in
both sexes, pancreatic exocrine atrophy in females and
testicular atrophy in males.
Some
evidence of carcinogenicity (thyroid gland follicular cell tumors)
in male rats,
but not in females.
Ref: Federal Register: April 18, 2002. Fluazinam;
Pesticide Tolerance. Final Rule.
http://www.fluoridealert.org/pesticides/fluazinam.fr.apr.18.2002.htm
-- In a carcinogenicity
study in rats, an increased incidence of
thyroid gland follicular cell tumors was observed in males.
In this study, there were statistically significant positive trends
for thyroid gland follicular cell adenocarcinomas and combined
follicular cell adenomas/adenocarcinomas. There was also a statistically
significant increase by pair-wise comparison of the high dose
group (40 mg/kg/day) with the control group for combined follicular
cell adenomas/adenocarcinomas. There was no treatment-related
increase in tumor incidence in female rats. The highest dose level
tested in this study was considered to be adequate but not excessive.
It was concluded that there was some evidence that the thyroid
tumors observed in the male rats in this study were treatment-related.
There were insufficient data to determine whether the thyroid
gland tumors may have been due to disruption
of thyroid-pituitary homeostasis.
Ref: US EPA Pesticide Fact Sheet. Fluazinam.
August 10, 2001.
http://www.epa.gov/opprd001/factsheets/fluazinam.pdf
-- Cancer (oral, dermal,
inhalation). Increases in thyroid
gland follicular cell tumors in male rats; increases in hepatocellular
(liver) tumors in male mice.\2\
-- iii. Cancer. Since fluazinam has been
classified as Suggestive evidence of carcinogenicity, but not
sufficient to assess human carcinogenic potential, an
exposure assessment was not performed.
Ref: Federal Register. September 7, 2001.
Fluazinam; Pesticide Tolerance. Final Rule.
http://www.fluoridealert.org/pesticides/fluazinam.fr.sept.7.2001.htm
-- In subchronic and
chronic toxicity studies, fluazinam targeted the following organs:
liver, lung, uterus, testes, pancreas, thymus, thyroid,
stomach, eyes and brain... Thyroid toxicity was less common, but
included follicular hyperplasia and cystic
thyroid follicles. Endocrine-related effects included small
and/or flaccid testes, testicular tubular atrophy, pancreatic
exocrine atrophy and thymic hyperplasia.
-- Long-term studies
in both rats and mice provided some evidence of treatment-induced
oncogenicity of the thyroid (follicular
cell adenomas and adenocarcinomas) and liver (hepatocellular
adenomas and carcinomas). Although tumours of this type may be
the result of a non-genotoxic and non-linear mode of action, no
data was provided on potential modes of action (e.g., enzyme induction,
thyroid hormone levels). There was insufficient mechanistic
data to determine the mode of action. A Q was generated at 5.40
¥ 10 -2 in the absence of a demonstrated mode of action.
Ref:
Canada: Regulatory
Note REG2003-12. Fluazinam. Pest
Management Regulatory Agency. Health Canada. Ottawa. October 27,
2003.
http://www.fluorideaction.org/pesticides/fluazinam.canada.report2003.pdf
Flubendiamide
- Insecticide - CAS No. 272451-65-7
Results
of a reproductive toxicity study in rats (exposure route not stated):
Thyroid, liver, uterine, thymus,
and spleen weight changes in 2000
and 20000 ppm F1 and F2 pups.
Ref: TSCA Health & Safety Study
Cover Sheet "Public Display Copy"
http://www.epa.gov/opptintr/tsca8e/doc/8ehq/2004/november04/8ehq-1004-15768a.pdf
••
This
document was cited at EPA's
site: "TSCA 8(e) and FYI Submissions Received from 11-15-04-11-26-04".
It is important to note this as the document itself does not identify
flubendiamide or its CAS No.
•• This
study was conducted in the laboratory of The Institute of Environmental
Toxicology - Japan
•• Source of Data/Study
Sponsor: Bayer Material Science Corporation, 100 Bayer Road, Pittsburg
PA 15205
Flucarbazone-sodium
- Herbicide
- CAS No. 181274-17-9
-- 90-Day oral toxicity
in nonrodents (dogs). NOAEL = 33.8 mg/kg/day in males and 35.2
mg/kg/day in females with the occurrence of slight, adaptive induction
of hepatic microsomal enzymes LOAEL = 162 mg/kg/ day in males
and 170 mg/kg/day in females based on decreased
T4 levels, increased thyroxine-binding capacity, induction
of microsomal enzymes, gross pathology and histopathology in the
stomach, and histopathology in the liver in both sexes.
-- One year dog feeding LOAEL = 183 mg/kg/day based on decreased
body weight gain, decreased thyroxine,
increased N- demethylase, and increased liver weight.
-- 28-Day oral toxicity in nonrodents (dogs). NOAEL = 164 mg/kg/
day in males and 171 mg/kg/day in females LOAEL = 1,614 mg/kg/
day in males and 1,319 mg/kg/day in females based on decreased
body weight gain, decreased food consumption, decreased
T4 levels and increased thyroxine-binding capacity, induction
of microsomal enzymes, increased liver weight and liver histopathology
in both sexes.
Ref: Federal Register. September 29, 2000.
Flucarbazone-sodium; Time-Limited Pesticide Tolerances. Final
Rule.
http://www.fluoridealert.org/pesticides/flucarbazone_na.fr.sept2000.htm
SUBCHRONIC/CHRONIC
TOXICITY
-- Study # 870.3100. 28-Day oral toxicity in rodents (rats) NOAEL
= 27 mg/kg/day in males and 25 mg/kg/day in females. LOAEL = 266
mg/kg/day in males and 251 mg/kg/day in females based on
immunological changes in both sexes.
-- Study # 870.3150. 90-Day oral toxicity in nonrodents (dogs)
NOAEL = 33.8 mg/kg/day in males and 35.2 mg/kg/day in females
with the occurrence of slight, adaptive induction of hepatic microsomal
enzymes. LOAEL = 162 mg/kg/day in males and 170 mg/kg/day in females
based on decreased T4 levels,
increased thyroxine-binding capacity, induction of microsomal
enzymes, gross pathology and histopathology in the
stomach, and histopathology in the liver
in both sexes.
-- Study # 870.3100. 90-Day oral toxicity in rodents (rats) NOAEL
= 73.5 mg/kg/day in males and 102 mg/kg/day in females LOAEL =
287 mg/kg/day in males and 358 mg/kg/day in females based on immunological
findings in both sexes
-- Study # 870.4300. 2-Year Chronic toxicity/carcinogenicity in
rats NOAEL = 125 mg/kg/day in males and females LOAEL = 1,000
mg/kg/day in males and females based on
decreased body weight and increased food consumption in females,
thickened mucosa of the glandular stomach in both sexes, inflammatory
infiltrates (males), vacuolation of the squamous epithelium in
the fore-stomach (females) and immunological
effects in males. no evidence of carcinogenicity
-- Study # 870.4100b. Chronic toxicity in dogs NOAEL = 35.9 mg/kg/day
in males and 37.1 mg/kg/day in females. LOAEL = 183 mg/kg/day
in males and 187 mg/kg/day in females based upon body
weight gain depression and increased N-demethylase levels
in both sexes, decreased T4 levels
and marginally increased liver weight
in females.
-- Study # 870.3150. 28-Day oral toxicity in nonrodents (dogs)
NOAEL = 164 mg/kg/day in males and 171 mg/kg/day in females. LOAEL
= 1,614 mg/kg/day in males and 1,319 mg/kg/day in females based
on decreased body weight gain, decreased
food consumption, decreased T4 levels and
increased thyroxine-binding capacity, induction of microsomal
enzymes, increased
liver weight and liver histopathology in both sexes.
Ref: US EPA Pesticide Fact Sheet for Flucarbazone-sodium.
September 29, 2000.
http://www.epa.gov/opprd001/factsheets/flucarbazone.pdf
Flufenacet
- Herbicide - CAS No. 142459-58-3
-- 21-day dermal (rats):
Dermal Irritation NOEL = 1000 mg/kg/day (males and females) Systemic
NOEL = 20 mg/kg/day (males) Systemic NOEL = 150 mg/kg/day (females)
Systemic LOEL = 150 mg/kg/day for males and 1000 mg/kg/day for
females based on clinical chemistry data (decreased
T4 and FT4 levels in both sexes) and centrilobular
hepatocytomegaly in females.
-- Special Studies: In a 55-day dog study subcutaneous via mini-pump
with Thiadone [flufenacet metabolite] support the hypothesis that
limitations in glutathione interdependent pathways and antioxidant
stress result in metabolic lesions in the
brain and heart following flufenacet exposure. Non guideline
studies provide evidence supporting hypothesis of an extra
thyroidal mechanism to explain alterations in circulating thyroid
hormone concentrations.
Ref: US EPA. Pesticide Fact Sheet. Flufenacet
Reason for Issuance: Conditional Registration Date Issued: April
1998.
http://www.epa.gov/opprd001/factsheets/flufenacet.pdf
A 84-day rat feeding
study with a No Observed Effect Level (NOEL) less than 100 ppm
(6.0 mg/kg/day) for males and a NOEL of 100 ppm (7.2 mg/kg/day)
for females and with a Lowest Observed Effect Level (LOEL) of
100 ppm (6.8 mg/kg/day) for males based on suppression
of thyroxine (T4) level and a LOEL of 400 ppm (28.8 mg/kg/day)
for females based on hematology and clinical chemistry findings.
Ref: Federal Register. September 23, 1998.
Flufenacet; Time-Limited Pesticide Tolerance. Final Rule.
http://www.fluoridealert.org/pesticides/flufenacet.fr.sept.23.1998.htm
-- Based on the toxicological findings for flufenacet relating
to endocrine disruption effects, flufenacet
should be considered as a candidate for evaluation as an endocrine
disrupter when the criteria are established ... there is concern
for thyroid hormone disruption.
Subchronic toxicity:
-- A 13-week mouse feeding study with a NOAEL of 100 ppm (18.2
mg/ kg/day for males and 24.5 mg/kg/day for females), and a LOAEL
of 400 ppm (64.2 mg/kg/day for males and 91.3 mg/kg/day for females)
based on histopathology of the liver,
spleen and thyroid.
-- A 13-week dog dietary study with a NOAEL
of 50 ppm (1.70 mg/ kg/day for males and 1.67 mg/kg/day for females),
and a LOAEL of 200 ppm (6.90 mg/kg/day for males and 7.20 mg/kg/day
for females), based on evidence that the bio-transformation capacity
of the liver has [[Page 16601]] been exceeded (as indicated by
increase in LDH, liver weight, ALK and hepatomegaly), globulin
and spleen pigment in females, decreased
T4 and ALT values in both sexes, decreased albumin in males,
and decreased serum glucose in females.
-- A 21-day rabbit dermal study with the dermal irritation NOAEL
of 1,000 mg/kg/day for males and females, and a systemic NOAEL
of 20 mg/kg/day for males and 150 mg/kg/day for females, and a
systemic LOAEL of 150 mg/kg/day for males and 1,000 mg/kg/day
for females based on clinical chemistry data (decreased
T4 and FT4 levels in both sexes) and centrilobular hepatocytomegaly
in females.
-- Chronic toxicity - A 1-year dog chronic feeding study with
a NOAEL was 40 ppm (1.29 mg/kg/day in males and 1.14 mg/kg/day
in females), and a LOAEL of 800 ppm (27.75 mg/kg/day in males
and 26.82 mg/kg/day in females) based on increased alkaline phosphatase,
kidney, and liver weight in both sexes, increased cholesterol
in males, decreased T2, T4 and ALT values
in both sexes, and increased incidences
of microscopic lesions in the brain, eye, kidney, spinal cord,
sciatic nerve, and liver.
Ref: Federal Register. March 29, 2000. Notice
of Filing a Pesticide Petition to Establish a Tolerance for Certain
Pesticide Chemicals in or on Food.
http://www.fluoridealert.org/pesticides/flufenacet.fr.mar.29.2000.htm
Flufenoxuron
- Acaracide, Insecticide, Herbicide - CAS No. 101463-69-8
-- Abstract: Flufenoxuron
(Benzoylphenyl urea derivative) - antimoulting insecticide Ð is
recently used for controlling insect reproduction in cultivated
areas. The study determined the hazardous effects of the applied
dose-treatment during the critical period of rat embryonic development
and the induction of growth retardation. In the present work,
flufenoxuron was intragastrically administered by stomach intubation
to pregnant rats at concentration levels 0 & 20 mg/kg b.wt.
in saline solution every other day on gestation day 7 till parturition.
Experimental and control pregnant rats were sacrificed on days
13 & 16 of gestation and the foetuses were fixed in 10 percent
formol saline. Histological abnormalities
of thyroid, liver and kidneys of mothers
as well as of skeletal axial and appendicular regions of foetuses
were investigated. Foetuses
maternally treated with flufenoxuron exhibited delayed
differentiation of chondrification and ossification of axial and
appendicular regions. The observed defects in foetuses may be
attributed to the histological abnormalities of thyroid,
liver and kidneys
of maternal tissues as well as to the direct effect of
the parents as a result of the insecticide or its metabolites
on the affected structures during early morphogenesis and differentiation.
Ref: J. Egypt. Ger. Soc. Zool., Vol. 25(B),
65-81, 1998. PATTERNS OF DEVELOPMENTAL DEFECTS OF RAT FOETUSES
MATERNALLY TREATED WITH AN ENVIRONMENTAL ANTIMOULTING INSECTICIDE
FLUFENOXURON; by Karim,
S.A.
http://www.egsz.org/BiologicalCurrentContent/Zoology/Comparative%20Physiology/TOXICOLOGY.htm
Flumioxazin
- Herbicide - CAS No. 103361-09-7
-- Rats. A 90-day subchronic
toxicity study was conducted in rats, with dietary intake levels
of 0, 30, 300, 1,000 and 3,000 ppm flumioxazin technical (98.4%
purity). The NOAEL of 300 ppm was based on decreased bwts; anemia;
increases in absolute and/or relative liver, kidney, brain, heart,
and thyroid weights, and histological
changes in the spleen, liver, and bone marrow related to the anemia.
-- A second 90-day subchronic toxicity study was conducted with
a sample of flumioxazin technical of typical purity (94.8%) at
dietary concentrations of 0, 30, 300, 1,000, and 3,000 ppm. The
NOAEL was 30 ppm based on anemia and related hematological changes;
increases in liver, heart, kidney, and thyroid
weights; and histological changes in the spleen, liver, and bone
marrow related to the anemia.
Ref: Federal Register: February 14, 2001
[Notices] [Page 10292-10301]. Notice of Filing a Pesticide Petition
to Establish a Tolerance for a Certain Pesticide Chemical in or
on Food.
http://www.fluoridealert.org/pesticides/Flumioxazin.FR.Feb.14.2001.htm
Fluoxastrobin
- Fungicide - CAS No. 193740-76-0
-- Subchronic toxicity...
A 14-week feeding study in dogs demonstrated a NOAEL of 3.0 mg/kg
bwt/day based on decreased body weights
and food consumption, and liver effects (enzyme induction, increased
liver weights, cytoplasmic change), and thyroid
effects (decreased T3)
Ref: Federal Register: April 23, 2003. Fluoxastrobin;
Notice of Filing a Pesticide Petition to Establish a Tolerance
for a Certain Pesticide Chemical in or on Food.
http://www.fluoridealert.org/pesticides/fluoxastrobin.fr.Apr23.2003.htm
-- In response to a
comment submitted to EPA by FAN Pesticide Project, EPA stated:
FAN suggested that a 14-week feeding
study using dogs showed an effect on the thyroid, which seems
to conflict with the statement that ``...There is no evidence
to suggest that fluoxastrobin has any primary endocrine disruptive
potential.'' FAN stated that a ``discussion or rationale'' addressing
this should have been provided. EPA does
believe that the thyroid effects seen in the dog study indicated
that fluoxastrobin is an endocrine disruptor. An effect
on the thyroid gland, even though this gland is part of the endocrine
system, does not necessarily mean that endocrine disruption has
or will occur. In this case, the effects
observed in the thyroid gland were induced by effects fluoxastrobin
had on liver enzymes and are therefore considered secondary.
--
Combined chronic toxicity / carcinogenicity--rats.
decreased body weight, decreased body weight
gain, and decreased food efficiency
in both sexes; decreased
spleen weight in males; and
microscopic lesions in the uterus of females. The
apparent increase in tumors in the uterus and thyroid were addressed
and resolved by an Agency committee, which
concluded that no carcinogenic concern exists for fluoxastrobin.
Ref: Federal Register. September 16, 2005.
Fluoxastrobin; Pesticide Tolerances. Final Rule.
http://www.fluorideaction.org/pesticides/fluoxastrobin.fr.sept16.05.html
Fluquinconazole
- Fungicide
- CAS No. 136426-54-5
-- Groups of 40 male
Sprague Dawley rats were fed a diet containing fluquinaconazole
at concentrations of 0 (control) or 100 ppm for 14 days. Twenty
rats per dose group were killed and necropsied on day 15. The
remaining animals were kept for a further 14 days on a treatment-free
diet then killed and necropsied... Hormone assays for thyroxine
(T4), triiodothyronine (T3), thyrotropin (TSH) and reverse triiodothyronine
(RT3) were conducted but the details of the assay methods were
not provided... Histopathology of
the thyroid was reported and focussed on 3 parameters; colloid
depletion, follicular cell hypertrophy and follicular cell hyperplasia...
Histopathology of the thyroid showed the
most distinctive finding to be the increased incidences of follicular
epithelial hyperplasia of the thyroid (11/20) compared with 0/20
in controls at day 15). An increase in the incidence of severe
folicular hypertrophy and severe or very severe colloid depletion
was considered to be also indicative of increase in thryoidtoxicity
in fluquinconazole-treated animals. Severe to very severe colloidal
depletion (5/20 animals compared with 1/20 in controls), severe
follicular cell hypertrophy (3/20 compared wtih 0/20 in controls)
and slight to moderate follicular epithelial hyperplasia (4/20
compared with 1/20 in controls) was present in the thyroid at
the end of the recovery period. In conclusion, administration
of fluquinconazole to male rats resulted in changes in thyroid
hormone homeostasis manifested by histopathological changes int
he thyroid... (DP 47301)
-- Oral long-term toxicity and carcinogenicity. 2-year dietary
study in rats. groups of 50 male and 50 female outbred albino
Sprague-Dawley CRL :COBS CD(SD)BR rats were administered fluquinconazole
(93.2% purity) in the diet at concentrations of 0 (control), 1,
20 or 100 ppm. Additionally 20 animals/sex/dose designated for
the interim-kill received the test compound at concentrations
of 0, 1, 5, 10 or 100 ppm for 12 months... In the thyroid
gland a significantly higher incidence in follicular
cell tumors were noted in the 100 ppm dose level in both
sexes. Historical tumor incidences provided showed that the slight
statistically non-significant increase in thyroid
follicular cell tumors at the lowest and intermediate dose
levels were at the upper limit of the historical control range
and therefore in the absence of a dose response they were considered
to be not of toxicological significance.
-- The rat was the most sensitive species
to fluquinconazole compared with the dog and mouse. The
main target organs were the liver, kidney and thyroid... For the thyroid tumors in
the rat, a correlation between induction of liver UDGPT and imbalances
in thyroid hormone (increase in TSH and reduction in T4) and histopathological
changes in the thyroid was demonstrated. Disturbance of thyroid
hormone homeostasis is a well recognised mechanism for the induction
of thyroid tumours. Futher this is considered to be secondary
to the observed liver enzme induction. A clear NOEL for
thyroid tumors and the induction of thryoid effects was
established.
--
Acute inhalation toxicity. Groups of 5 male and 5 female Crl:CD
(SD)BR Spraque-Dawley rats were exposed head-only to a dust aerosol
of fluquinconzole (98.7% purity), at mean analytical concentrations
of 0, 0.082, 0.24, 1.08 or 4.56 mg/l for four hours. All surviving
animals were killed and necropsied after a 14-day observation
period... signs of toxicity inclding ataxia, hunched posture and
respiratory distress were observed at the 0.24 mg/l dose for up
to 4 days and at the higher dose levels until death... In the
thyroid, the incidence and severity
of thyroid effects including colloid depletion, follicular cell
hyperplasia and hypertrophy did not show a clear treatment-relationship
(statistically significant compared with
controls at 100 and 200 ppm but not at 400 ppm and 10 mg/kg
bw/day dose levels). The NOEl was 5 ppm (0.45 mg/kg bw/day) based
on increased liver and kidney weights and histopathological changes
in the liver, kidney and thyroid
at the higher dose level of 20 ppm... The
liver, thyroid and kidneys were noted to be the target organs
of the test compound and significant changes in these organs
indicative of significant hepatic enzyme induction were considered
to be relevant for risk assessment.
Ref: Evaluation on: Fluquinconazole. May
1999. No. 184. Evaluation of Fully Approved or Provisionally Approved
Products. Department for Environment, Food and Rural Affairs,
Pesticides Safety Directorate, Mallard House, Kings Pool, 3 Peasholme
Green, York YO1 7 PX, UK. Available online:
http://www.pesticides.gov.uk/citizen/evaluations/evallist.htm
Flutolanil
- Fungicide - CAS No.
66332-96-5
Subchronic toxicity.
A 84-day rat feeding study with a No Observed Effect Level ( NOEL)
less than 100 ppm [6.0 mg/kg/day] for males and a NOEL of 100
ppm [7.2 mg/kg/day] for females and with a Lowest Observed Effect
Level (LOEL) of 100 ppm [6.8 mg/kg/day] for males based on suppression
of thyroxine (T4) level and a LOEL of 400 ppm [28.8 mg/kg/day]
for females based on hematology and clinical chemistry findings.
A 13-week mouse feeding study with a NOEL of 100 ppm [18.2 mg/kg/day
for males and 24.5 mg/kg/day for females] and a LOEL of 400 ppm
[64.2 mg/kg/day for males and 91.3 mg/kg/day for females] based
on histopathology of the liver, spleen and thyroid.
A 13-week dog dietary study with a NOEL of 50 ppm [1.70 mg/kg/day
for males and 1.67 mg/kg/day for females] and a LOEL of 200 ppm
[6.90 mg/ kg/day for males and 7.20 mg/kg/day for females] based
on evidence that the bio-transformation capacity of the liver
has been exceeded, (as indicated by increase in LDH, liver weight,
ALK and hepatomegaly), globulin and spleen pigment in females,
decreased T4 and [[Page 34180]] ALT
values in both sexes, decreased albumin in males, and decreased
serum glucose in females. A 21-day rabbit dermal study with the
dermal irritation NOEL of 1,000 mg/kg/day for males and females
and a systemic NOEL of 20 mg/kg/day for males and 150 mg/kg/day
for females and a systemic LOEL of 150 mg/kg/day for males and
1,000 mg/kg/day for females based on clinical chemistry data (decreased
T4 and FT4 levels in both sexes)
and centrilobular hepatocytomegaly in females.
Ref: Federal Register: June 23, 1998 [Page
34176-34184]. Notice of Filing of Pesticide Petitions.
http://www.fluoridealert.org/pesticides/flutolanil.fr.june.23.1998.htm
Fluxofenim
- Herbicide safener - CAS No. 88485-37-4
Chronic/Subchronic
Toxicity Studies. Fluxofenim: Liver and kidney effects; Thyroid
effects at high doses (dogs)...
Target Organs - Fluxofenim: Liver, kidney, and
thyroid.
Ref: Ciba-Geigy Material Safety Data Sheet
for Concep-III.
http://www.fluoridealert.org/pesticides/Fluxofenim.MSDS.Ciba.1996.htm
also available at
http://www.horizononline.com/MSDS_Sheets/737.txt
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