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Atrazine
CASRN 1912-24-9
Contents
0209
Atrazine; CASRN 1912-24-9
Health assessment information on a chemical substance is included in IRIS only
after a comprehensive review of chronic toxicity data by U.S. EPA health
scientists from several Program Offices and the Office of Research and
Development. The summaries presented in Sections I and II represent a
consensus reached in the review process. Background information and
explanations of the methods used to derive the values given in IRIS are
provided in the Background Documents.
STATUS OF DATA FOR Atrazine
File On-Line 09/30/1987
Category (section) Status Last Revised
----------------------------------------- -------- ------------
Oral RfD Assessment (I.A.) on-line 10/01/1993
Inhalation RfC Assessment (I.B.) no data
Carcinogenicity Assessment (II.) no data
_I. CHRONIC HEALTH HAZARD ASSESSMENTS FOR NONCARCINOGENIC EFFECTS
__I.A. REFERENCE DOSE FOR CHRONIC ORAL EXPOSURE (RfD)
Substance Name -- Atrazine
CASRN -- 1912-24-9
Last Revised -- 10/01/1993
The oral Reference Dose (RfD) is based on the assumption that thresholds exist
for certain toxic effects such as cellular necrosis. It is expressed in units
of mg/kg-day. In general, the RfD is an estimate (with uncertainty spanning
perhaps an order of magnitude) of a daily exposure to the human population
(including sensitive subgroups) that is likely to be without an appreciable
risk of deleterious effects during a lifetime. Please refer to the Background
Document for an elaboration of these concepts. RfDs can also be derived for
the noncarcinogenic health effects of substances that are also carcinogens.
Therefore, it is essential to refer to other sources of information concerning
the carcinogenicity of this substance. If the U.S. EPA has evaluated this
substance for potential human carcinogenicity, a summary of that evaluation
will be contained in Section II of this file.
___I.A.1. ORAL RfD SUMMARY
Critical Effect Experimental Doses* UF MF RfD
-------------------- ----------------------- ----- --- ----------
Decreased body weight NOAEL: 70 ppm 100 1 3.5E-2
gain (3.5 mg/kg-day) mg/kg-day
2-Year Rat Feeding LOAEL: 500 ppm
Study (25 mg/kg-day)
Ciba-Geigy Corp., 1986
Cardiac toxicity and NOAEL: 150 ppm
moderate-to-severe (4.97 mg/kg-day)
dilation of the right
atrium LOAEL: 1000 ppm
(33.65 mg/kg/-day, male
1-Year Dog Feeding 33.8 mg/kg-day, female)
Study
Ciba-Geigy Corp., 1987a
*Conversion Factors and Assumptions -- 1 ppm = 0.05 mg/kg-day (assumed rat
food consumption)
___I.A.2. PRINCIPAL AND SUPPORTING STUDIES (ORAL RfD)
Ciba-Geigy Corporation. 1986. MRID No. 00141874, 00157875, 00158930,
40629302. HED Doc. No. 005940, 006937. Available from EPA. Write to FOI,
EPA, Washington, DC 20460.
Ciba-Geigy Corporation, Agricultural Division. 1987a. MRID No. 40431301,
41293801. HED Doc. No. 006718, 006937, 007647. Available from EPA. Write to
FOI, EPA, Washington, DC 20460.
Groups of Sprague-Dawley rats (20/sex/dose for the chronic study,
50/sex/dose for the oncogenicity study) were administered atrazine in the diet
for 2 years at dietary concentrations of 0, 10, 70, 500, and 1000 ppm (0, 0.5,
3.5, 25 and 50 mg/kg-day) (Ciba-Geigy Corp., 1986). An additional 10 rats/sex
were placed on control and high-dose (1000 ppm) diets for a 12-month interim
sacrifice and 10/sex (control and high-dose) for a 13-month sacrifice (the
1000 ppm group was placed on control diet for 1 month prior to sacrifice).
Animals were caged individually and received food and water ad libitum.
In males, survival was increased in a dose-related manner (p <0.003, using
the Cox Tarone test) and was significantly higher in males receiving 1000 ppm
when compared with controls (p=0.0055, using pairwise comparison). In
contrast, survival in females was decreased in a dose-related manner (p value
for a negative trend = 0.0016) and was significantly lower (p=0.0042) in high-
dose females when compared with controls.
Mean body weights were significantly depressed (p<0.01) in males and
females receiving 500 (M: 8%; F: 19%) and 1000 (M: 19%; F: 27%) ppm with the
exception of mean weights for males in the last 2 months of the study. The
24-month weight gain in the high-dose animals was 76% of control for males and
64.5% of control for females. In the recovery groups, the weight gain for
month 13 for males previously receiving 1000 ppm was 63 +/- 14.6 g, compared
with 20 +/- 17.9 g for controls (p<0.01), and for females previously receiving
1000 ppm it was 56 +/- 31.6 g, compared with 16 +/- 11.9 g for controls
(p<0.01). However, the mean weight at 13 months in these males was still
significantly (p<0.01) lower than controls.
In females receiving 1000 ppm, statistically significantly (p<0.05) lower
mean red cell count, hemoglobin and hematocrit were noted at 6, 12, and 18
months when compared with controls. The values were somewhat depressed in
high-dose females at 24 months: however, only four females were used for
clinical studies. Red cell count, hemoglobin and hematocrit were also
decreased in the 10 females receiving 1000 ppm and scheduled for sacrifice at
12 months. The values approached control levels at 13 months in the 1000 ppm
recovery group. All values for parameters in dosed males were similar to
those in the control groups with the exception of an increased mean platelet
count at 6 months in rats receiving 1000 ppm. Increase platelet counts were
also seen at 6 and 12 months in females receiving 1000 ppm. The level of
serum triglycerides in high-dose males (56.55 +/- 18.12 mg/dL) was, in
general, lower than control values (139.26Ò88.35 mg/dL) throughout the study;
however, the decrease was significant (p<0.05) only at 6 months. In groups
scheduled for the 12-month sacrifice, the level in high-dose males (103.1 +/-
47.81 mg/dL) was significantly lower (p<0.01) than in control males (228.3 +/-
95.44 mg/dL). At the 13-month sacrifice, the triglyceride level was similar
in control males and those that had previously received 1000 ppm. In females,
glucose levels were decreased (p<0.01) in the high-dose group at 3, 6 and 12
months when compared with controls.
The absolute weight of liver and kidney in high-dose males sacrificed at
12 months was significantly (p<0.05) lower than controls. The mean weight of
the liver was 14.71 +/- 2.81 g for the high-dose groups and 19.7 +/- 3.46 g
for the controls; the mean weight of the kidneys was 3.67 +/- 0.4 g for high-
dose males, compared with 4.39 +/- 0.58 g for controls.
At 24 months, the mean absolute weights of liver and kidney in high-dose
males were lower than those of controls, but the decrease was not
statistically significant. There were no other changes in absolute organ
weights of males and females. There were several increases in organ-to-body
weight ratios in high-dose animals that were significant (p<0.05) when
compared with controls but they were not accompanied by changes in absolute
organ weights. These changes were the result of decreased body weights.
Acinar hyperplasia of the mammary gland and epithelial hyperplasia of the
prostate were increased in males receiving 1000 ppm when compared to controls.
In females receiving 500 or 1000 ppm, there was an increased myeloid
hyperplasia in the bone marrow of both the femur and sternum. It was reported
that the bone marrow changes, as well as an increase in extramedullary
hematopoiesis in the spleen, were sequellae related to mammary fibroadenomas
and adenocarcinomas. The myeloid hyperplasia was characterized by a decrease
in the number of fat cells in the marrow and an increase in the hematopoietic
tissue, particularly cells of the granulocytic series. Muscle degeneration
(femoral muscle) was found in both high-dose males and females. Retinal
degeneration was increased in both males and females, the incidence being
significantly (p<0.05) higher in high-dose females than in controls. In high-
dose females there was an increase in coagulative centrolobular necrosis in
the liver.
Based on decreased body weight gain, the LEL for systemic toxicity is 500
ppm (25 mg/kg-day). The NOEL for systemic toxicity is 70 ppm (3.5 mg/kg-day).
Groups of 5-month-old beagle dogs (6/sex control, 4/sex low- and mid-dose,
and 6/sex high-dose) were administered atrazine for 1 year at dietary levels
of 0, 15, 150 and 1000 ppm (Male: 0, 0.48, 4.97 and 33.65 mg/kg-day; Female:
0, 0.48, 4.97 and 33.8 mg/kg-day) (Ciba-Geigy Corp., Agricultural Div.,
1987a). Animals received food and water ad libitum.
The most significant effect of atrazine administration was the syndrome of
cardiopathy, featuring discrete myocardial degeneration, which was most
prominently found in animals receiving 1000 ppm. Clinical signs referable to
cardiac toxicity, such as ascites, cachexia, labored/shallow breathing, and
abnormal EKG (irregular heart beat and increased heart rate, decreased P-II
values, atrial premature complexes, atrial fibrillation) were first observed
as early as 17 weeks into the study. Gross pathological examination revealed
moderate-to-severe dilation of the right atrium (and occasionally the left
atrium), microscopically manifest as atrophy and myelosis (degeneration of the
atrial myocardium).
Three animals had to be sacrificed during the study in moribund condition:
one 150 ppm male on day 75; one 1000 ppm female on day 113; and one 1000 ppm
male on day 250. Control and 15 ppm animals survived the entire study period
without incident. The study authors concluded that only the death of the
high-dose female was compound related.
No effects were observed in the low- and mid-dose groups. Therefore,
based on the effects observed in the high-dose group, the LEL for systemic
toxicity is 1000 ppm (Male: 33.65 mg/kg-day; Female: 33.8 mg/kg-day). The
NOEL for systemic toxicity is 150 ppm (4.97 mg/kg-day).
One hundred twenty male and 120 female Charles River CD rats were randomly
distributed into four treatment groups, 0, 10, 50 and 500 ppm (Male: 0, 0.69,
3.5 and 34.97 mg/kg-day; Female: 0, 0.76, 3.78 and 37.45 mg/kg-day) (Ciba-
Geigy Corp., Agricultural Div., 1987b). Male rats were placed on the control
and test diets at 47 days of age and females at 48 days of age. They were
maintained on these diets for a period of 10 weeks prior to mating. Males and
females were housed together in a 1:1 ratio for mating. One litter was
produced in each generation. After weaning of the first generation, 30 males
and 30 females were selected for the second parental generation. The
remaining male parental animals were sacrificed on days 133-134 of the study.
Animals selected for the second generation were exposed to test diets for 12
weeks prior to mating. Mating was conducted in the same manner as for the
first generation. Parental males were sacrificed on day 138 of the study and
parental females on days 138, 139 and 152 after weaning of their litters.
Body weights were statistically significantly (p<0.05) lower for high-dose
animals (14% and 16% for the F0 and F1 males, respectively; 14% and 13% for
the F0 and F1 females, respectively) throughout the study. Body weight gains
were also statistically significantly depressed (p<0.05) at the high-dose (27%
and 17% for the F0 and F1 males, respectively; 28% and 15% for the F0 and F1
females, respectively). At the mid-dose, sporadic decreases in body weight
gain were also noted. These changes were not considered to be treatment-
related since they were occasional and sporadic. Food consumption was
statistically significantly reduced for males and females during the premating
period for both parental generations and for F1 females on days 0-7 of
gestation. No other effects were noted.
Based on the effects observed at the high-dose, the LEL for parental
toxicity is 500 ppm (Male: 34.97 mg/kg-day; Female: 37.45 mg/kg-day). The
NOEL for parental toxicity is 50 ppm (Male: 3.5 mg/kg-day; Female: 3.78 mg/kg-
day).
In the initial Office of Pesticide Programs (OPP) review of this study for
reproductive effects, a NOEL and LEL of 10 and 50 ppm were selected based on a
statistically significant (p<0.05) decrease in the F2 generation male pup body
weights at day 21. The registrant subsequently submitted the original and
revised "Healy analyses" for the F1 and F2 male and female body weights. This
method of analysis was proposed by M.J.R. Healy, who observed that
"experiments using animal litters as experimental units usually require a
weighted analysis to allow for variations in litter size" and described
"methods for assessing appropriate weights" (Healy, 1972). The registrant
contended that a review of the original Healy analysis procedure determined
that pairwise comparisons should not have been conducted in the absence of a
statistically significant F-statistic. The correct procedure, as the
registrant pointed out, is to carry out pairwise comparisons only if the F-
Test is significant, thereby controlling the Type I (false-positive) error
rate. Therefore, the revised Healy analysis should be considered correct as
far as determining which differences are statistically significant.
Therefore, the registrant concluded that the NOEL for reproductive toxicity
should be greater than 10 ppm.
Upon reviewing this additional information, the OPP toxicologists and
statisticians concluded that the NOEL and LEL for reproductive toxicity be
changed to 50 and 500 ppm respectively, based on reduced body weight in the F2
generation male pups at lactation days 7 and 14. Further rationale for this
change is described below.
Body weights of the F2 male pups in the 10 and 50 ppm groups at day 7
(13.39 g and 13.66 g, respectively) and day 14 (28.26 g and 28.33 g,
respectively) are essentially the same even though they are less than the
control group value (14.01 g and 29.32 g for days 7 and 14, respectively).
The day 4 post-culling data should be used as a control time point to
determine the lactational effect endpoint. The added week of additional
compound intake, especially at 500 ppm, is expected to further increase the
body weight reduction changes already seen. The only change noted at 500 ppm
was a consistent, though not statistically significant, fall in F2 male pup
body weights at 500 ppm (9.02, 13.28 and 28.06 g, for days 4, 7 and 14,
respectively) when compared to the post culling controls (9.29, 14.01 and
29.32 g for days 4, 7 and 14, respectively). Therefore, the decreases in body
weights of the F2 male pups are considered to be an equivocal biological
effect.
Based on an equivocal decrease in body weights of the F2 male pups, the
LEL for reproductive toxicity is 500 ppm (Male: 34.97 mg/kg-day; Female: 37.45
mg/kg-day). The NOEL for reproductive toxicity is 50 ppm (Male: 3.5 mg/kg-
day; Female: 3.78 mg/kg-day).
___I.A.3. UNCERTAINTY AND MODIFYING FACTORS (ORAL RfD)
UF -- The uncertainty factor of 100 reflects 10 for interspecies extrapolation
and 10 for intraspecies-variability.
MF -- None
___I.A.4. ADDITIONAL STUDIES / COMMENTS (ORAL RfD)
In the previous review of atrazine, a core grade supplementary 2-year
feeding study in dogs (Ciba-Geigy Corp., 1964) with a systemic NOEL and LEL of
0.35 and 3.54 mg/kg-day, respectively, was included under other data reviewed.
Since the stated NOEL for this study was approximately 10-fold lower than the
NOEL established in a newer 1-year dog study (Ciba-Geigy Corp., 1987a), a
reevaluation of the older study by the Office of Pesticide Programs (OPP) was
considered necessary. OPP's reevaluation noted the following deficiencies: 1)
purity of test material was not reported; 2) only 3/dogs/sex were used,
animals were obtained from different suppliers and weights of individual
animals were not provided; 3) animals were given double portions of food on
Saturdays and none on the following day; 4) individual animal feeding and
observation data were not submitted; 5) the study reported that
tetrachloroethylene, an antihelmenthic, was used several times a day. This
chemical can cause effects on certain blood parameters. Since hematological
effects were noted in the study, the possibility that this antihelmenthic
chemical caused or contributed to these effects cannot be ruled out.; 6)
limited clinical chemistries determinations; and 7) urinalysis determinations
were carried out on cage collected urine. Based on the many deficiencies and
reporting omissions in this study, which have not been satisfactorily
addressed by the sponsor, the study can no longer be classified as core
supplementary and has been down-graded to invalid.
1) 2-Year Feeding/Oncogenicity - rat: Principal study -- see previous
description; core grade minimum (Ciba-Geigy Corp., 1986).
2) 1-Year Feeding - dog: Co-principal study -- see previous description; core
grade minimum (Ciba-Geigy Corp., 1987a).
3) 2-Generation Reproduction - rat: See previous description; core grade
minimum (Ciba-Geigy Corp., Agricultural Div., 1987b).
4) Developmental toxicity - rat: Core grade minimum (Ciba-Geigy Corp.,
1984a).
Groups of pregnant Charles River rats (27/dose) were administered atrazine
by gastric intubation at dose levels of 0, 10, 70 and 700 mg/kg-day. Dosing
occurred daily and was performed on days 6 through 15 of presumed gestation.
The control group received 10 ml/kg-day of 3% corn starch containing 0.5%
Tween 80, which was the volume equivalent to that received by treated rats.
Maternal toxicity was observed during and after the treatment period at
the 700 mg/kg-day dose level (HDT). Signs of toxicity in the HDT included
death (21 of 27 dams), reduced food consumption, reduced weight gain,
salivation, ptosis, swollen abdomen, oral/nasal discharge and bloody vulva.
Maternal toxicity was also observed at the 70 mg/kg-day dose level. Toxicity
signs in this group included reduced food consumption, reduced body weight and
reduced weight gain. No maternal toxicity was observed in the 10 mg/kg-day or
control groups. Based on the above effects, the NOEL and LEL for maternal
toxicity are 10 and 70 mg/kg-day, respectively.
At 70 mg/kg-day, there were statistically significant increases by both
fetal and litter incidence in skeletal variations indicating delayed
ossification. These included: skull not completely ossified, presphenoid not
ossified, teeth not ossified, metacarpals not ossified, metacarpals bipartite,
and distal phalanx not ossified. The incidences of these effects in the
control and low-dose groups were comparable. Based on these effects, the NOEL
and LEL for developmental toxicity are 10 and 70 mg/kg-day.
5) Developmental toxicity - rabbit: Core grade minimum (Ciba-Geigy Corp.,
1984b)
Groups of pregnant New Zealand White rabbits (19/dose) were administered
atrazine at dose levels of 0, 1, 5 and 75 mg/kg-day on days 7 through 19 of
gestation. The control group (vehicle control) received 5 ml/kg-day of 3%
corn starch with Tween 80, which was a volume equivalent to that received by
rabbits treated with atrazine.
Maternal toxicity was noted in the high-dose group only. From the body
weight gain data, it is not apparent that there was a dose related decrease in
body weight gain at all dose levels as originally reported. A treatment-
related effect was noted in the body weight gain in the high-dose group during
the dosing period, with a rebound increase in body weight gain following the
dosing period. Combined-dosing period and post-dosing period body weight gain
for the high-dose group also shows a decrease, as does the corrected body
weight gain for the high-dose group. Food consumption data for these periods
also support the observation of a high-dose group effect. Low food efficiency
was noted in the high-dose group during the dosing period and for the combined
period including the dosing period and post-dosing period. There appears to
be increased food efficiency in the post-dosing period, which supports what
was noted for food consumption and the rebound in body weight gain in the post
dosing period. Other signs of maternal toxicity related to clinical
observations included an increase in "stool: little, none and/or soft" in the
high-dose group, along with the evidence of "blood on vulva/in cage" in the
high-dose group. No treatment-related signs were noted in the low- or mid-
dose groups. Cesarean section data showed no additional maternal toxicity
data; however, developmental toxicity was noted at the high-dose in the form
of increased total resorptions and resorptions per dam, decreased total live
fetuses and live fetuses per dam (litter size), an increased post-implantation
loss and a decrease in mean fetal weight. Therefore, based on the effects
observed at the highest dose tested, the LEL for maternal and developmental
toxicity is 75 mg/kg-day. The NOEL for maternal and developmental toxicity is
5 mg/kg-day.
Other Data Reviewed:
1) 91-Week Feeding/Oncogenicity - mouse: Core grade guideline (Ciba-Geigy
Corp., Agricultural Division, 1987c).
Groups of CD-1 mice (60/sex/dose) were administered atrazine for 91 weeks
at dietary levels of 0, 10, 300, 1500, and 3000 ppm (Male: 0, 1.4, 38.4, 194.0
and 385.7 mg/kg-day; Female: 0, 1.6, 47.9, 246.9 and 482.7 mg/kg-day).
Animals received food and water ad libitum.
Dose-related reductions were observed in mean body weight gain in both
sexes of mice receiving 1500 or 3000 ppm. In mice receiving 1500 ppm, the
decrease in mean body weight gain at weeks 12 and 91 were 33% and 23% for
males, respectively, and 14.3% and 11% for females, respectively. In mice
receiving 3000 ppm, the decrease in mean body weight gain at weeks 12 and 91
were 40.6% and 24.4% for males, respectively, and 12.1% and 48.5% for females,
respectively.
At the termination of the study, statistically significant (p<0.05)
reductions in mean erythroid variables (erythrocyte count, hematocrit and
hemoglobin) were observed in mid- and high-dose males and high-dose females.
High-dose females also had increased neutrophil percentage (p<0.05) and
decreased lymphocyte percentage (p<0.05) when compared with controls.
Dose-related cardiac thrombi (primarily in the atria) were seen in male
and female mice. The incidence for males was 3/59, 6/60, 3/60, 7/60 and 9/58
for the 0, 10, 300, 1500 and 3000 ppm dose groups, respectively. The
incidence for females was 3/60, 4/59, 2/60, 11/60 and 26/60 for the 0, 10,
300, 1500 and 3000 ppm dose groups, respectively. This effect was observed
primarily in those animals who had died or were killed in the course of the
study.
Based on the above effects, the LEL for systemic toxicity is 1500 ppm
(Male: 194.0 mg/kg-day; Female: 246.9 mg/kg-day). The NOEL for systemic
toxicity is 300 ppm (Male: 38.4 mg/kg-day; Female: 47.9 mg/kg-day).
2) Developmental toxicity - rat: Core grade minimum (Ciba-Geigy, Corp.,
1971).
Groups of pregnant rats were administered atrazine by gavage at dose
levels of 0, 100, 500 and 1000 mg/kg-day on days 6 through 15 of gestation. In
the high-dose group, 7 out of the 30 animals treated died. Slight weight
losses in females were observed at mid-dose. A reduction in mean fetal
weights and an increase in the number of embryonic and fetal resorptions were
observed in the mid- and high-dose groups. Based on the above effects, the
NOEL and LEL for maternal toxicity and fetotoxicity are 100 and 500 mg/kg-day,
respectively.
Data Gap(s): None
___I.A.5. CONFIDENCE IN THE ORAL RfD
Study -- High
Data Base -- High
RfD -- High
The principal studies are of good quality and are given high confidence
ratings. Additional studies are supportive of the principal studies and of
good quality. Therefore, the data base is given a high confidence rating.
High confidence in the RfD follows.
___I.A.6. EPA DOCUMENTATION AND REVIEW OF THE ORAL RfD
Source Document -- This assessment is not presented in any existing U.S. EPA
document.
Other EPA Documentation -- None
Agency Work Group Review -- 07/08/1986, 12/09/1986, 05/20/1987, 06/22/1988, 02/21/1990,
11/04/1992, 12/16/1992, 09/23/1993
Verification Date -- 09/23/1993
___I.A.7. EPA CONTACTS (ORAL RfD)
Please contact the Risk Information Hotline for all questions concerning this
assessment or IRIS, in general, at (513)569-7254 (phone), (513)569-7159 (FAX)
or RIH.IRIS@EPAMAIL.EPA.GOV (internet address).
__I.B. REFERENCE CONCENTRATION FOR CHRONIC INHALATION EXPOSURE (RfC)
Substance Name -- Atrazine
CASRN -- 1912-24-9
Not available at this time.
_II. CARCINOGENICITY ASSESSMENT FOR LIFETIME EXPOSURE
Substance Name -- Atrazine
CASRN -- 1912-24-9
Not available at this time.
_VI. BIBLIOGRAPHY
Substance Name -- Atrazine
CASRN -- 1912-24-9
Last Revised -- 10/01/1993
__VI.A. ORAL RfD REFERENCES
Ciba-Geigy Corporation. 1964. MRID No. 00059213. HED Doc. No. 000525,
002917, 006605. Available from EPA. Write to FOI, EPA, Washington, DC
20460.
Ciba-Geigy Corporation. 1971. MRID No. 00038041. HED Doc. No. 002917.
Available from EPA. Write to FOI, EPA, Washington, DC 20460.
Ciba-Geigy Corporation. 1984a. MRID No. 00143008, 40566302. HED Doc. No.
006131, 006761, 006937. Available from EPA. Write to FOI, EPA, Washington,
DC 20460.
Ciba-Geigy Corporation. 1984b. MRID No. 00143006, 40566301. HED Doc. No.
006131, 006761, 006937. Available from EPA. Write to FOI, EPA, Washington,
DC 20460.
Ciba-Geigy Corporation. 1986. MRID No. 00141874, 00157875, 00158930,
40629302. HED Doc. No. 005940, 006937. Available from EPA. Write to FOI,
EPA, Washington, DC 20460.
Ciba-Geigy Corporation, Agricultural Division. 1987a. MRID No. 40431301,
41293801. HED Doc. No. 006718, 006937, 007647. Available from EPA. Write to
FOI, EPA, Washington, DC 20460.
Ciba-Geigy Corporation. 1987b. MRID No. 40431303, 41986801. HED Doc. No.
006718, 06937. Available from EPA. Write to FOI, EPA, Washington, DC 20460.
Ciba-Geigy Corporation, Agricultural Division. 1987c. MRID No. 40431302,
40629301. HED Doc. No. 006718, 006765, 006937. Available from EPA. Write to
FOI, EPA, Washington, DC 20460.
Healy, M.R.C. 1972. Animal Litters as Experimental Units. J. Royal Stat.
Soc. (Series C), Applied Statistics. 21(2): 155-159.
__VI.B. INHALATION RfD REFERENCES
None
__VI.C. CARCINOGENICITY ASSESSMENT REFERENCES
None
_VII. REVISION HISTORY
Substance Name -- Atrazine
CASRN -- 1912-24-9
-------- -------- --------------------------------------------------------
Date Section Description
-------- -------- --------------------------------------------------------
03/01/1988 I.A.5. Confidence levels revised
08/22/1988 I.A. Withdrawn; new oral RfD in preparation
09/07/1988 I.A. Revised oral RfD summary added
10/01/1989 VI. Bibliography on-line
03/01/1990 I.A. Withdrawn; new oral RfD in preparation
03/01/1990 VI.A. Oral RfD references withdrawn
05/01/1990 I.A. Oral RfD summary replaced; RfD unchanged
05/01/1990 VI.A. Oral RfD references replaced
01/01/1991 I.A. Text edited
01/01/1991 II. Carcinogen assessment now under review
01/01/1992 IV. Regulatory Action section on-line
12/01/1992 I.A. Oral RfD summary noted as pending change
12/01/1992 I.A.6. Work group review date added
01/01/1993 I.A. Withdrawn; new oral RfD in preparation
01/01/1993 I.A. Work group review date added
01/01/1993 VI.A. Oral RfD references withdrawn
10/01/1993 I.A. Oral RfD summary replaced; RfD changed
10/01/1993 VI.A. Oral RfD references replaced
VIII. SYNONYMS
Substance Name -- Atrazine
CASRN -- 1912-24-9
Last Revised -- 09/30/1987
1912-24-9
A 361
AATREX
AATREX 4L
AATREX 80W
AATREX NINE-O
2-AETHYLAMINO-4-CHLOR-6-ISOPROPYLAMINO-1,3,5-TRIAZIN
2-AETHYLAMINO-4-ISOPROPYLAMINO-6-CHLOR-1,3,5-TRIAZIN
AKTIKON
AKTIKON PK
AKTINIT A
AKTINIT PK
ARGEZIN
ATAZINAX
ATRANEX
ATRASINE
ATRATOL A
ATRAZIN
Atrazine
ATRED
ATREX
CANDEX
CEKUZINA-T
2-CHLORO-4-ETHYLAMINEISOPROPYLAMINE-s-TRIAZINE
1-CHLORO-3-ETHYLAMINO-5-ISOPROPYLAMINO-2,4,6-TRIAZINE
1-CHLORO-3-ETHYLAMINO-5-ISOPROPYLAMINO-s-TRIAZINE
2-CHLORO-4-ETHYLAMINO-6-ISOPROPYLAMINO-1,3,5-TRIAZINE
2-CHLORO-4-ETHYLAMINO-6-ISOPROPYLAMINO-s-TRIAZINE
6-CHLORO-N-ETHYL-N'-(1-METHYLETHYL)-1,3,5-TRIAZINE-2,4-DIAMINE
2-CHLORO-4-(2-PROPYLAMINO)-6-ETHYLAMINO-s-TRIAZINE
CRISATRINA
CRISAZINE
CYAZIN
FARMCO ATRAZINE
FENAMIN
FENAMINE
FENATROL
G 30027
GEIGY 30,027
GESAPRIM
GESOPRIM
GRIFFEX
HUNGAZIN
HUNGAZIN PK
INAKOR
OLEOGESAPRIM
PRIMATOL
PRIMATOL A
PRIMAZE
RADAZIN
RADIZINE
STRAZINE
TRIAZINE A 1294
s-TRIAZINE, 2-CHLORO-4-ETHYLAMINO-6-ISOPROPYLAMINO-
1,3,5-TRIAZINE-2,4-DIAMINE, 6-CHLORO-N-ETHYL-N'-(1-METHYLETHYL)-
VECTAL
VECTAL SC
WEEDEX A
WONUK
ZEAZIN
ZEAZINE
Last updated: 5 May 1998
URL: http://www.epa.gov/iris/SUBST/0209.HTM
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