1979 

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National Cancer Institute 

CARCINOGENESIS 

Technical Report Series 

No. 137 

BIOASSAY OF 

DIAZINON 

FOR POSSIBLE CARCINOGENICITY 

CAS No. 333-41-5 

NCI-CG-TR-137 

U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE 

Public Health Service 

National Institutes of Health 

BIOASSAY OF
 

DIAZINON
 

FOR POSSIBLE CARCINOGENICITY
 

Carcinogenesis Testing Program
 

Division of Cancer Cause and Prevention
 

National Cancer Institute
 

National Institutes of Health
 

Bethesda, Maryland 20014
 

U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE
 

Public Health Service
 

National Institutes of Health
 

DREW Publication No. (NIH) 79-1392
 
11

 
BIOASSAY OF
 

DIAZINON
 

FOR POSSIBLE CARCINOGENICITY
 

Carcinogenesis Testing Program
 

Division of Cancer Cause and Prevention
 

National Cancer Institute
 

National Institutes of Health
 

FOREWORD; This report presents the results of the bioassay of 

diazinon conducted for the Carcinogenesis Testing Program, Division of Cancer Cause and Prevention, National Cancer 

Institute (NCI), National Institutes of Health, Bethesda, Maryland. This is one of a series of experiments designed to 

determine whether selected environmental chemicals have the 

capacity to produce cancer in animals. A negative result, in
 

which the test animals do not have a greater incidence of cancer
 

than control animals, does not necessarily mean that a test
 

chemical is not a carcinogen, inasmuch as the experiments are
 

conducted under a limited set of circumstances. A positive
 

result demonstrates that a test chemical is carcinogenic for
 

animals under the conditions of the test and indicates that
 

exposure to the chemical is a potential risk to man. The actual
 

determination of the risk to man from chemicals found to be
 

carcinogenic in animals requires a wider analysis.
 

CONTRIBUTORS: This bioassay of diazinon was conducted by Gulf
 

South Research Institute (GSRl), New Iberia, Louisiana, initially
 

under direct contract to NCI and currently under a subcontract to
 

Tracer Jitco, Inc., prime contractor for the NCI Carcinogenesis
 

Testing Program.
 

The experimental design for this bioassay is based on guidelines
 

for carcinogen bioassays in small animals that have been
 

established by NCI (1). The doses for the chronic studies were
 

selected by Drs. E. E. Storrs (2) and 0. G. Fitzhugh (3,4). The
 

principal investigator was Mr. R. J. Wheeler (2). Histologic
 

examination of animal tissues was performed by Drs. E. Bernal (2)
 

and R. A. Ball (2), and the diagnoses included in this report
 

represent the interpretation of these pathologists.
 

Animal pathology tables and survival tables were compiled at EG&G
 

Mason Research Institute (5). Statistical analyses were
 

performed by Dr. J. R. Joiner (3) and Ms. P. L. Yong (3), using,
 methods selected for the bioassay program by Dr. J. J. Gart (6).
 

ill
 
The chemical was reanalyzed at Midwest Research Institute (7)
 

upon completion of the bioassay. Chemicals were analyzed at GSRI
 

by Mr. Wheeler (2) and dosed feed mixtures by Mr. S. M. Billedeau
 

(2). The results of these analyses were reviewed by Dr. C. W.
 

Jameson (3).
 

This report was prepared at Tracer Jitco (3) under the direction
 

of NCI. Those responsible for the report at Tracer Jitco were
 

Dr. C. R. Angel, Acting Director of the Bioassay Program; Dr. S.
 

S. Olin, Deputy Director for Science; Dr. J. F. Robens,
 

toxicologist; Dr. R. L. Schueler, pathologist; Dr. G. L. Miller,
 

Mr. W. D. Reichardt, Ms. L. A. Owen, and Ms. M. S. King, 

bioscience writers; and Dr. E. W. Gunberg, technical editor, 

assisted by Ms. Y. E. Presley. 

The following scientists at NCI were responsible for evaluating
 

the bioassay experiment, interpreting the results, and reporting
 

the findings: Dr. Kenneth C. Chu, Dr. Cipriano Cueto, Jr., Dr. J.
 

Fielding Douglas, Dr. Richard A. Griesemer, Dr. Thomas E. Hamm,
 

Dr. William V. Hartwell, Dr. Morton H. Levitt, Dr. Harry A.
 

Milman, Dr. Thomas W. Orme, Dr. A. R. Patel,, Dr. Sherman F.
 

Stinson, Dr. Jerrold M. Ward, and Dr. Carrie E. Whitmire.
 

(1) Carcinogenesis Testing Program, Division of Cancer Cause and
 

Prevention, National Cancer Institute, National Institutes
 

of Health, Bethesda, Maryland.
 

(2) Gulf South Research Institute, Atchafalaya Basin
 

Laboratories, P. 0. Box 1177, New Iberia, Louisiana.
 

(3) Tracor Jitco, Inc., 1776 East Jefferson Street, Rockville,
 

Maryland.
 

(4) 4208 Dresden Street, Kensington, Maryland.
 

(5) EG&G Mason Research Institute, 1530 East Jefferson
 

Street, Rockville, Maryland.
 

(6) Mathematical Statistics and Applied Mathematics Section,
 

Biometry Branch, Field Studies and Statistics, Division of
 

Cancer Cause and Prevention, National Cancer Institute,
 

National Institutes of Health, Bethesda, Maryland.
 

(7) Midwest Research Institute, 425 Volker Boulevard, Kansas
 

City, Missouri.
 

iv
 
SUMMARY
 

A bioassay of diazinon for possible carcinogenicity was conducted
 

by administering the test chemical in feed to F344 rats and
 

B6C3F1 mice.
 

Groups of 50 rats and 50 mice of each sex were administered
 

diazinon at one of two doses, either 400 or 800 ppm for the rats
 

and either 100 or 200 ppm for the mice, for 103 weeks and were
 

then observed for an additional 1 or 2 weeks. Matched controls
 

consisted of groups of 25 untreated rats and 25 untreated mice of
 

each sex. All surviving animals were killed at the end of 104 or
 

105 weeks.
 

There was no appreciable effect of administration of diazinon on
 

mean body weights of rats or mice of either sex. Mortality was
 

not increased in any of the dosed groups of rats or mice, when
 

related to that in the corresponding controls, and survival was
 

84% or greater in all dosed and control groups of animals at week
 

78. Some hyperactivity was noted in the dosed groups of both
 

species; however, both the rats and mice may have been able to
 

tolerate higher doses. Sufficient numbers of animals were at
 

risk in all groups for the development of late-appearing tumors.
 

No tumors occurred in any of the dosed groups of rats or mice of
 

either sex at incidences that could clearly be related to the
 

administration of diazinon.
 

It is concluded that under the conditions of this bioassay, 

diazinon was not carcinogenic for F344 rats or B6C3F1 mice of 

either sex. 
vi

 
TABLE OF CONTENTS
 

I. Introduction 1.
 

II. Materials and Methods 5
 

A. Chemical 5
 

B. Dietary Preparation 5
 

C. Animals 7
 

D. Animal Maintenance 7
 

E. Subchronic Studies 9
 

F. Chronic Studies 11
 

G. Clinical and Pathologic Examinations 11
 

H. Data Recording and Statistical Analyses 14
 

III. Results - Rats 21
 

A. Body Weights and Clinical Signs (Rats) 21
 

B. Survival (Rats) 21
 

C. Pathology (Rats) 24
 

D. Statistical Analyses of Results (Rats) '26
 

IV. Results - Mice 37
 

A. Body Weights and Clinical Signs (Mice) 37
 

B. Survival (Mice) 37
 

C. Pathology (Mice) 40
 

D. Statistical Analyses of Results (Mice) 41
 

V. Discussion 49
 

VI. Bibliography 51
 

APPENDIXES
 

Appendix A. Summary of the Incidence of Neoplasnc in
 

Rats Administered Diazinon in the Diet ..... 53
 

Table Al Summary of the Incidence of Neoplasm in
 

Male Rats Administered Diazinon in
 

the Diet 55
 

vii
 
Table A2 Summary of the Incidence of Neoplasms in 

Female Rats Administered Diazinon in 

the Diet 59 

Appendix B Summary of the Incidence of Neoplasms in 

Mice Administered Diazinon in the Diet ... 63 

Table Bl Summary of the Incidence of Neoplasms in 

Male Mice Administered Diazinon in 

the Diet 65 

Table B2 Summary of the Incidence of Neoplasms in 

Female Mice Administered Diazinon in 

the Diet 68 

Appendix C Summary of the Incidence of Nonneoplastic 

Lesions in Rats Administered Diazinon in 

the Diet 73 

Table Cl Summary of the Incidence of Nonneoplastic 

Lesions in Male Rats Administered 

Diazinon in the Diet 75 

Table C2 "Summary of the Incidence of Nonneoplastic 

Lesions in Female Rats Administered 

Diazinon in the Diet 79 

Appendix D Summary of the Incidence of Nonneoplastic 

Lesions in Mice Administered Diazinon 

in the Diet 83 

Table Dl Summary of the Incidence of Nonneoplastic 

Lesions in Male Mice Administered 

Diazinon in the Diet 85 

Table D2 Summary of the Incidence of Nonneoplastic 

Lesions in Female Mice Administered 

Diazinon in the Diet 88 

Appendix E Analyses of Formulated Diets for 

Concentrations of Diazinon 91 

TABLES 

Table 1 Diazinon Subchronic Feeding Studies in 

Rats and Mice • 10 

viii 
Page 

Table 2 Diazinon Chronic Feeding Studies in 

Rats 12 

Table 3 Diazinon Chronic Feeding Studies in 

Mice 13 

Table 4 Analyses of the Incidence of Primary Tumors 

in Male Rats Administered Diazinon in 

the Diet 28 

Table 5 Analyses of the Incidence of Primary Tumors 

in Female Rats Administered Diazinon in 

the Diet 33 

Table 6 Analyses of the Incidence of Primary Tumors 

in Male Mice Administered Diazinon in 

the Diet 43 

Table 7 Analyses of the Incidence of Primary Tumors 

in Female Mice Administered Diazinon 

in the Diet 46 

FIGURES 

Figure 1 Growth Curves for Rats Administered 

Diazinon in the Diet 22 

Figure 2 Survival Curves for Rats Administered 

Diazinon in the Diet 23 

Figure 3 Growth Curves for Mice Administered 

Diazinon in the Diet 38 

Figure 4 Survival Curves for Mice Administered 

Diazinon in the Diet 39 

IX
 

I. INTRODUCTION
 

CH3
 

Oiazinon
 

Diazinon (CAS 333-41-5; NCI C08673) is the common name
 

recommended by the British Standards Institution, the International Standardization Organization, and the Entomological
 

Society of America (Martin and Worthing, 1977) for the organophosphate insecticide, 0,0-diethyl 0-(2-isopropyl-6-methyl-4­

pyrimidinyl)phosphorothioate. It was marketed first in 1954 as
 

an insecticide and acaricide (Bartsch, 1974) and has been used
 

since that time as a dust or spray in agriculture, on rangeland
 

and wasteland, in industrial establishments, and in the home
 

(Ayers and Johnson, 1976). The EPA currently permits its use on
 

76 food crops, cotton, and pasture grasses (EPA, 1969-1973).
 

Diazinon has also been applied as a livestock spray or dip and
 

has been administered in the feed to farm and domestic animals
 

for the control of ectoparasites (Rossoff, 1974; Miicke et al.,
 

1970). In 1974, diazinon was the fifth most extensively used
 

1
 
organophosphate insecticide in the United States (Ayers and
 

Johnson, 1976). Of the 7 million pounds estimated to have been
 

sold that year, approximately two-thirds were expended in
 

agriculture, and the remaining third in commercial establishments
 

and in the home (Ayers and Johnson, 1976), by either commercial
 

pest control operators or consumers.
 

The acute oral LD of diazinon is 250 mg/kg and 285 mg/kg in
 

male and female Sherman rats, respectively (Gaines, 1969),
 

100-150 mg/kg in male albino rats (Bruce et al., 1955) and 82
 

mg/kg in male albino mice (Bruce et al., 1955). The toxic
 

effects of diazinon are due to cholinesterase inhibition. Male
 

albino rats administered 100 ppm diazinon in the diet for 4 weeks
 

had reduced cholinesterase activities of the red cells, and rats
 

administered 1,000 ppm for 4 weeks had reduced cholinesterase
 

activity in both the red cells and the brain (Bruce et al., 1955).
 

Toxicity is increased by metabolic conversion to the oxygen
 

analog (Matsumura, 1975), and decreased, specifically in mammals,
 

by hydrolysis of the pyrimidine ester of either diazinon,
 

diazoxon, or hydroxydiazinon (Eto, 1974).
 

Diazinon, like other organophosphate insecticides, is rapidly
 

degraded in the environment. It has a half-life of 2 to 4 weeks
 

in soil depending on soil type and climate (Bartsch, 1974).
 
Residues may occur in food crops, and are currently established
 

at concentrations no greater than 1 to 0.1 ppm in various crops
 

intended for human consumption, and 60 to 10 ppm in forage crops
 

(Code of Federal Regulations, 1976).
 

Diazinon was selected by the Carcinogenesis Testing Program
 

because of its widespread use in agriculture and related
 

industries as well as in the home and because of the possibility
 

that residues may contaminate food.
 

II. MATERIALS AND METHODS
 

A. Chemical
 

Diazinon was obtained in a single batch (Lot No. Fl-741306) for
 

the chronic study from CIBA-GEIGY Corp., Greensboro, North
 

Carolina. The identity and purity of this batch was confirmed in
 

analysis at Gulf South Research Institute. Elemental analyses
 

(C, H, N, P, S) were correct for C.-H^N-O-PS, the
 

molecular formula of diazinon. Thin-layer chromatography showed
 

a single spot. Vapor-phase chromatography indicated an impurity
 

of approximately 2%, which was not identified. Nuclear magnetic
 

resonance, infrared, and ultraviolet spectra were in agreement
 

with the structure. Reanalysis of this batch of diazinon at
 

Midwest Research Institute after completion of the bioassay
 

indicated that the material had not changed under the condition
 

of storage for approximately 4 years.
 

B. Dietary Preparation
 

All diets were formulated using Wayne Lab Blox Meal (Allied
 

Mills, Inc. Chicago, 111.) to which was added the required amount
 
of diazinon for each dietary concentration. Small amounts of
 

acetone (Mallinckrodt Inc., St. Louis, Mo.) were used as an aid
 

to uniform dispersion of the test compound in the feed. The
 

diets were mixed mechanically to assure homogeneity and to allow
 

for evaporation of the acetone. Corn oil (Louana , Opelousas
 

Refinery Co., Opelousas, Louisiana) equal to 2% of the final
 

weight of feed was then added, primarily as a dust suppressant. Diets for control animals were the same as those for dosed
 

animals, except for the absence of diazinon. Formulated diets
 

were stored at ambient room temperature until used, but no longer
 

than 1 week.
 

The stability of diazinon in feed was checked by analyzing
 

formulated diets for the concentration of diazinon at intervals
 

over a period of 7 days. No significant change in diazinon
 

concentration was detected in diets containing 50 and 3,200 ppm
 

diazinon on standing at ambient temperature for this period.
 

Diazinon formulated diets were checked analytically at intervals
 

during the chronic study to assess the accuracy of the diet
 

preparations and the homogeneity of the mixtures. Results are
 

summarized in Appendix E. At each dietary concentration, the
 

mean of the analytical concentrations for the checked samples was
 
within 97% of the theoretical concentration, and the coefficient
 

of variation was not more than 5.7% at any level.
 

C. Animals
 

F344 (Fischer) rats and B6C3F1 hybrid mice of each sex were
 

obtained from the NCI Frederick Cancer Research Center
 

(Frederick, Md.). After the rats were housed within the test
 

facility for 2 weeks and the mice for 4 weeks, they were assigned
 

to dosed or control groups.
 

D. Animal Maintenance
 

The rats were housed individually in hanging galvanized steel
 

mesh cages (Hoeltge, Cincinnati, Ohio), and the mice were housed
 

five per cage in polypropylene cages (Lab Products, Inc.,
 

Garfield, N.J.). The mouse cages were covered with polyester
 

filter bonnets (Lab Products, Inc.), and the filter bonnets were
 

sanitized once per week. The cages for the rats were sanitized
 

every 2 weeks, and those for the mice were sanitized twice per
 

week. Cages and racks were washed in an industrial washer
 

(Industrial Washing Machine Corp., Matawan, N.J.) at 82 C with
 
Acclaim® detergent (Economics Laboratory, Inc., St. Paul,
 

Minn.) and then rinsed. Absorbent Kimpak® cage liners
 

(Kimberly Clark Corp., Neenah, Wis.) were placed under the rat
 

cages and were changed twice per week. Absorb-dri hardwood
 

chip bedding (Lab Products, Inc.) was used in the mouse cages and
 

was changed twice per week. Feed jars, water bottles, sipper
 

tubes, and stoppers were sanitized twice per week. The filter
 

bonnets, feed jars, water bottles, sipper tubes, and stoppers
 

were washed in a Vulcan Autosan washer (Louisville, Ky.) at
 

82 C, using Acclaim® detergent, and then rinsed.
 

Cage racks for each species were rotated to a new position in the
 

room once per week; at the same time, each cage was moved to a
 

different row within the same column of a rack. Rats and mice
 

were housed in separate rooms. Control and dosed rats were
 

housed on the same rack, whereas cages for control and dosed mice
 

were placed in separate racks in the same room. Diazinon was the
 

only compound on test in each room.
 

The animal rooms were maintained at 22 to 24 C, and the relative
 

humidity was 40 to 70%. The air was filtered through permanent
 

air maze filters (Air Maze Incom International, Cleveland, Ohio)
 

and was changed 10 to 12 times per hour. Fluorescent lighting
 
provided illumination 10 hours per day. Food and tap water were
 

provided ad libitum. Fresh feed was provided twice per week.
 

E. Subchronic Studies
 

Subchronic feeding studies were conducted with rats and mice to
 

estimate the maximum tolerated doses (MTD's) of diazinon, on the
 

basis of which concentrations (referred to in this report as
 

"high" and "low" doses), were chosen for administration in the
 

chronic studies. Groups of 10 rats and 10 mice of each sex were
 

fed diets containing diazinon at one of several doses for 13
 

weeks, and groups of 10 control animals of each species and sex
 

were administered basal diet only. The animals were weighed once
 

per week. Table 1 shows the doses fed, the survivals of animals
 

in each dosed group at the end of the study, and the mean body
 

weights of dosed groups of animals at week 13, expressed as
 

percentages of mean body weights of corresponding control
 

groups. At the end of the 13 weeks, all surviving animals were
 

killed and necropsied.
 

Three deaths occurred among the male rats and four among the
 

females rats at 3,200 ppm. Mean body weight gains were
 

appreciably decreased only in groups of males or females at doses
 
Table 1. Diazinon Subchronic Feeding Studies in
 

Rats and Mice
 

Male Female
 

Mean Weight Mean Weight
 

at Week 13 at Week 13
 

Dose as % of as % of
 

(ppm) Survival (a) Control Survival (a) Control
 

Rats(b)
 

0 10/10 100 10/10 100
 

50 10/10 103 10/10 96
 

100 10/10 102 10/10 96
 

200 10/10 103 10/10 98
 

400 10/10 100 10/10 97
 

800 10/10 99 10/10 98
 

1,600 10/10 93 10/10 85
 

3,200 7/10 78 6/10 67
 

Mice(b)
 

0 10/10 100 10/10 100
 

50 10/10 97 10/10 101
 

100 10/10 99 10/10 102
 

200 9/10 92 9/10 96
 

400 10/10 93 10/10 100
 

800 10/10 84 10/10 78
 

1,600 0/10 0/10
 

3,200 0/10 0/10
 

(a) Number surviving/number in group.
 

(b) No gross abnormalities were observed in necropsied animals at
 

any dose, and microscopic examination of tissues of animals
 

surviving the high doses showed no pathologic changes.
 

10
 
of 1,600 or 3,200 ppm. The diazinon was more toxic to the mice
 

than to the rats, causing deaths of all animals at both 1,600 and
 

3,200 ppm, and decreases in mean body weight gain at 800 ppm.
 

The low and high doses for the chronic studies were set at 400
 

and 800 ppm for rats; and 100 and 200 ppm for mice.
 

F. Chronic Studies
 

The test groups, doses administered, and durations of the chronic
 

studies are shown in tables 2 and 3.
 

G. Clinical and Pathologic Examinations
 

All animals were observed twice per day for signs of toxicity,
 

weighed at 2-week intervals, and palpated for masses at each
 

weighing. Observations of sick, tumor-bearing, and moribund
 

animals were recorded daily. Moribund animals and animals that
 

survived to the end of the bioassay were killed with pentobarbital and necropsied.
 

The pathologic evaluation consisted of gross and microscopic
 

11
 
Table 2. Diazinon Chronic Feeding Studies in Rats
 

Sex and Initial Diazinon Time on Study
 

Test No. of in Diet(b) Dosed Observed
 

Group Animals (a) (ppm) (weeks) (weeks)
 

Male
 

Matched-Control 25 0 105
 

Low-Dose 50 400 103 2
 

High -Dose 50 800 103 2
 

Female
 

Matched-Control 25 0 104-105
 

Low-Dose 50 400 103 1
 

High-Dose 50 800 103' 1
 

(a) All rats were approximately 7 weeks of age when placed on study.
 

(b) Diets were provided ad libitum.
 

12
 
Table 3. Diazinon Chronic Feeding Studies in Mice
 

Sex and Initial Diazinon Time on Study
 

Test No. of in Diet(b) Dosed Observed
 

Group Animals (a) (ppm) (weeks) (weeks)
 

Male
 

Matched-Control 25 0 105
 

Low-Dose 50 100 103 2
 

High -Dose 50 200 103 2
 

Female
 

Matched-Control 25 0 106
 

Low-Dose 50 100 103 2
 

High -Dose 50 200 103 2
 

(a) All mice were approximately 6 weeks of age when placed on study.
 

(b) Diets were provided ad libitum.
 

13
 
examination of major tissues, major organs, and all gross
 

lesions. The following tissues were examined microscopically:
 

skin, lungs and bronchi, trachea, bone and bone marrow, spleen,
 

lymph nodes, heart, salivary gland, liver, gallbladder (mice),
 

pancreas, stomach, small intestine, large intestine, kidney,
 

urinary bladder, pituitary, adrenal, thyroid, parathyroid,
 

mammary gland, prostate or uterus, testis or ovary, and brain.
 

Occasionally, additional tissues were also examined
 

microscopically. The different tissues were preserved in neutral
 

buffered 10% formalin, embedded in paraffin, sectioned, and
 

stained with hematoxylin and eosin. Special staining techniques
 

were utilized when indicated for more definitive diagnosis.
 

Necropsies were also performed on all animals found dead, unless
 

precluded in whole or in part by autolysis or cannibalization.
 

Thus, the number of animals from which particular organs or
 

tissues were examined microscopically varies and does not
 

necessarily represent the number of animals that were placed on
 

study in each group.
 

H. Data Recording and Statistical Analyses
 

Pertinent data on this experiment have been recorded in an
 
automatic data processing system, the Carcinogenesis Bioassay
 

Data System (Linhart et al., 1974). The data elements include
 

descriptive information on the chemicals, animals, experimental
 

design, clinical observations, survival, body weight, and
 

individual pathologic results, as recommended by the
 

International Union Against Cancer (Berenblum, 1969). Data
 

tables were generated for verification of data transcription and
 

for statistical review.
 

These data were analyzed using the appropriate statistical
 

techniques described in this section. Those analyses of the
 

experimental results that bear on the possibility of
 

carcinogenicity are discussed in the statistical 'narrative
 

sections.
 

Probabilities of survival were estimated by the product-limit
 

procedure of Kaplan and Meier (1958) and are presented in this
 

report in the form of graphs. Animals were statistically
 

censored as of the time that they died of other than natural
 

causes or were found to be missing; animals dying from natural
 

causes were not statistically censored. Statistical analyses for
 

a possible dose-related effect on survival used the method of Cox
 

(1972) for testing two groups for equality and Tarone's (1975)
 

extensions of Cox's methods for testing for a dose-related
 

15
 
trend. One-tailed P values have been reported for all tests
 

except the departure from linearity test, which is only reported
 

when its two-tailed P value is less than 0.05.
 

The incidence of neoplastic or nonneoplastic lesions has been
 

given as the ratio of the number of animals bearing such lesions
 

at a specific anatomic site (numerator) to the number of animals
 

in which that site is examined (denominator). In most instances,
 

the denominators included only those animals for which that site
 

was examined histologically. However, when macroscopic examination was required to detect lesions prior to histologic sampling
 

(e.g., skin or mammary tumors), or when lesions could have
 

appeared at multiple sites (e.g., lymphomas), the denominators
 

consist of the numbers of animals necropsied.
 

The purpose of the statistical analyses of tumor incidence is to
 

determine whether animals receiving the test chemical developed a
 

significantly higher proportion of tumors than did the control
 

animals. As a part of these analyses, the one-tailed Fisher
 

exact test (Cox, 1970) was used to compare the tumor incidence of
 

a control group with that of a group of dosed animals at each
 

dose level. When results for a number of dosed groups (k) are
 

compared simultaneously with those for a control group, a
 

correction to ensure an overall significance level of 0.05 may be
 

16
 
made. The Bonferroni inequality (Miller, 1966) requires that the
 

P value for any comparison be less than or equal to 0.05/k. In
 

cases where this correction was used, it is discussed in the
 

narrative section. It is not, however, presented in the tables,
 

where the Fisher exact P values are shown.
 

The Cochran-Armitage test for linear trend in proportions, with
 

continuity correction (Armitage, 1971), was also used. Under the
 

assumption of a linear trend, this test determines if the slope
 

of the dose-response curve is different from zero at the one-


tailed 0.05 level of significance. Unless otherwise noted, the
 

direction of the significant trend is a positive dose relationship. This method also provides a two-tailed test of departure
 

from linear trend.
 

A time-adjusted analysis was applied when numerous early deaths
 

resulted from causes that were not associated with the formation
 

of tumors. In this analysis, deaths that occurred before the
 

first tumor was observed were excluded by basing the statistical
 

tests on animals that survived at least 52 weeks, unless a tumor
 

was found at the anatomic site of interest before week 52. When
 

such an early tumor was found, comparisons were based exclusively
 

on animals that survived at least as long as the animal in which
 

the first tumor was found. Once this reduced set of data was
 

17
 
obtained, the standard procedures for analyses of the incidence
 

of tumors (Fisher exact tests, Cochran-Armitage tests, etc.) were
 

followed.
 

When appropriate, life-table methods were used to analyze the
 

incidence of tumors. Curves of the proportions surviving without
 

an observed tumor were computed as in Saffiotti et al. (1972).
 

The week during which an animal died naturally or was sacrificed
 

was entered as the time point of tumor observation. Cox's
 

methods of comparing these curves were used for two groups;
 

Tarone's extension to testing for linear trend was used for three
 

groups. The statistical tests for the incidence of tumors which
 

used life-table methods were one-tailed and, unless otherwise
 

noted, in the direction of a positive dose relationship. Significant departures from linearity (P less than 0.05, two-tailed
 

test) were also noted.
 

The approximate 95 percent confidence interval for the relative
 

risk of each dosed group compared to its control was calculated
 

from the exact interval on the odds ratio (Gart, 1971). The
 

relative risk is defined as p,./p where p is the true
 

binomial probability of the incidence of a specific type of tumor
 

in a dosed group of animals and p is the true probability of
 

the spontaneous incidence of the same type of tumor in a control
 

18
 
group. The hypothesis of equality between the true proportion of
 

a specific tumor in a dosed group and the proportion in a control
 

group corresponds to a relative risk of unity. Values in excess
 

of unity represent the condition of a larger proportion in the
 

dosed group than in the control.
 

The lower and upper limits of the confidence interval of the
 

relative risk have been included in the tables of statistical
 

analyses. The interpretation of the limits is that in
 

approximately 95% of a large number of identical experiments, the
 

true ratio of the risk in a dosed group of animals to that in a
 

control group would be within the interval calculated from the
 

experiment. When the lower limit of the confidence interval is
 

greater than one, it can be inferred that a statistically
 

significant result (P less than 0.025 one-tailed test when the
 

control incidence is not zero, P less than 0.050 when the control
 

incidence is zero) has occurred. When the lower limit is less
 

than unity, but the upper limit is greater than unity, the lower
 

limit indicates the absence of a significant result while the
 

upper limit indicates that there is a theoretical possibility of
 

the induction of tumors by the test chemical, which could not be
 

detected under the conditions of this test.
 

19
 
20

 
III. RESULTS - RATS
 

A. Body Weights and Clinical Signs (Rats)
 

Mean body weights of the male and female rats were essentially
 

the same as those of corresponding controls (figure 1). Clinical
 

signs of hyperactivity in low- and high-dose males and high-dose
 

females and of discolored urine in the high-dose females were
 

noted. Bloating, vaginal bleeding, and vaginal discharge also
 

were noted in the dosed females. In addition, tissue masses were
 

observed at highest incidences in high-dose males and low-dose
 

females, and tachypnea was observed at a higher incidence in
 

dosed groups than in control groups.
 

B. Survival (Rats)
 

Estimates of the probabilities of survival for male and female
 

rats administered diazinon in the diet at the doses of this
 

bioassay, together with those for the matched controls, are shown
 

by the Kaplan and Meier curves in figure 2.
 

In male rats, the result of the Tarone test for dose-related
 

21
 
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trend in mortality is significant (P = 0.021), but in the
 

negative direction. An indicated departure from linear trend is
 

observed (P = 0.033), due to the fact that the low-dose group
 

survival was shorter than that of either the high-dose or the
 

control group. In females, the result of the Tarone test is not
 

significant.
 

In male rats 49/50 (98%) of each dosed group and 24/25 (96%) of
 

the control group were alive at week 78. In females, 44/50 (88%)
 

of each dosed group and 23/25 (92%) of the control group were
 

alive at week 78. Sufficient numbers of rats of each sex were at
 

risk for the development of late-appearing tumors.
 

C. Pathology (Rats)
 

Histopathologic findings on neoplasms in rats are summarized in
 

Appendix A, tables Al and A2; findings on nonneoplastic lesions
 

are summarized in Appendix C, tables Cl and C2.
 

A wide variety of neoplastic and nonneoplastic lesions occurred
 

among male and female rats with approximately equal frequency in
 

the control and dosed groups. In a few cases the incidence of a
 

24
 
particular lesion was higher in control groups than in dosed
 

groups.
 

Leukemia or lymphoma occurred in dosed and control groups of
 

rats of each sex. The increased incidence in low-dose males
 

(25/50 (50%)), compared with the corresponding controls (5/25
 

(20%)) and high-dose males (12/50 (24%)), is of questionable
 

significance. The leukemias were of the type usually seen in
 

aging F344 rats, involving liver, spleen, and lung and were
 

composed of neoplastic mononuclear cells.
 

Endometrial stromal polyps were observed at a higher incidence in
 

the low-dose (8/43 (19%)) and high-dose (11/49 (22%)) groups than
 

those in the control group (2/23 (9%)). However, this lesion is
 

commonly observed in F344 rats; thus, it appears that the
 

incidence of endometrial stromal polyps in this bioassay is not
 

related to administration of the test chemical.
 

This histopathologic examination provided no convincing evidence
 

for carcinogenicity of diazinon in F344 rats under conditions of
 

this bioassay.
 

25
 
D. Statistical Analyses of Results (Rats)
 

Tables 4 and 5 contain the statistical analyses of the incidences
 

of those primary tumors that occurred in at least two animals of
 

one group and at an incidence of at least 5% in one or more than
 

one group.
 

In female rats, the results of the Cochran-Armitage test for
 

dose-related trend in the incidence of tumors and those of the
 

Fisher exact test comparing the incidence of tumors in the
 

control group with that in each dosed group are not significant.
 

The result of the Fisher exact test in the incidence of lymphoma
 

or leukemia in male rats, shows that the incidence in the
 

low-dose group is significantly higher (P ** 0.011) than that in
 

the control group. However, the incidence in the high-dose group
 

and the results of the Cochran-Armitage test are not significant.
 

In each of the 95% confidence intervals for relative risk, shown
 

in the tables, except for the combined incidence of lymphoma and
 

leukemia in the low-dose male rats, the value of one is included;
 

this indicates the absence of significant positive results. It
 

should also be noted that each of the intervals has an upper
 

limit greater than one, indicating the theoretical possibility of
 

26
 
the induction of tumors by diazinon, which could not be detected
 

under the conditions of this test.
 

27
 
Table 4. Analyses of the Incidence of Primary Tumors in Male Rats
 

Administered Diazinon in the Diet (a)
 

Matched Low
 

Topography; Morphology Control Dose
 

Lung: Alveolar/Bronchiolar Adenoma
 

or Carcinoma (b) 1/24 (4) 0/48 (0)
 

P Values (c,d) N.S. N.S.
 

Relative Risk (f) 0.000
 

Lower Limit 0.000
 

Upper Limit 9.332
 

Weeks to First Observed Tumor 105
 —
 

Ixi
 

oo
 

Hematopoietic System:
 

Lymphoma or Leukemia (b) 5/25 (20) 25/50 (50)
 

P Values (c,d) N.S. P = 0.011
 

Departure from Linear Trend (e) P = 0.002
 

Relative Risk (f) 2.500
 

Lower Limit 1.107
 

Upper Limit 7.374
 

Weeks to First Observed Tumor 70 78
 

High
 

Dose
 

4/49 (8)
 

N.S.
 

1.959
 

0.211
 

94.428
 

105
 

12/50 (24)
 

N.S.
 

1.200
 

0.454
 

3.950
 

96 
Table 4. Analyses of the Incidence of Primary Tumors in Male Rats
 

Administered Diazinon in the Diet (a)
 

(continued) 

Matched Low
 

Topography: Morphology Control Dose
 

Pituitary: Carcinoma, NOS, or
 

Adenoma, NOS (b) 9/23 (39) 12/46 (26)
 

P Values (c,d) N.S. N.S.
 

Relative Risk (f) 0.667
 

Lower Limit 0.314
 

Upper Limit 1.555
 

Weeks to First Observed Tumor 79 84
 

K3 

V£> 

Adrenal: Pheochromocytoma (b) 3/24 (13) 2/49(4)
 

P Values (c,d) N.S. N.S.
 

Relative Risk (f) 0.327
 

Lower Limit 0.029
 

Upper Limit 2.693
 

Weeks to First Observed Tumor 95 105
 

High
 

Dose
 

19/42 (45)
 

N.S.
 

1.156
 

0.617
 

2.440
 

2/48(4)
 

N.S.
 

0.333
 

0.030
 

2.747
 

105
 

91 
Table 4. Analyses of the Incidence of Primary Tumors in Male Rats
 

Administered Diazinon in the Diet (a)
 

(continued)
 

Matched Low
 

Topography: Morphology Control Dose
 

Thyroid: C-cell Carcinoma (b) 2/22 (9) 0/44 (0)
 

P Values (c,d) N.S. N.S.
 

Relative Risk (f) 0.000
 

Lower Limit 0.000
 

Upper Limit 1.678
 

Weeks to First Observed Tumor 100
 —
 

u>
 

o
 

Thyroid: C-cell
 

Carcinoma or Adenoma (b) 4/22 (18) 5/44 (11)
 

P Values (c,d) N.S. N.S.
 

Relative Risk (f) 0.625
 

Lower Limit 0.153
 

Upper Limit 2.897
 

Weeks to First Observed Tumor 100 97
 

High
 

Dose
 

1/50 (2)
 

N.S.
 

0.220
 

0.004
 

4.055
 

105
 

5/50 (10)
 

N.S.
 

0.550
 

0.134
 

2.565
 

103
 
Table 4. Analyses of the Incidence of Primary Tumors in Male Rats
 

(continued)
 

Topography; Morphology
 

Pancreatic Islets: Islet-cell
 

Adenoma (b)
 

P Values (c,d)
 

Relative Risk (f)
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Testis: Interstitial-cell
 

Tumor (b)
 

P Values (c,d)
 

Relative Risk (f)
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Administered Diazinon in the Diet (a)
 

Matched Low
 

Control Dose
 

5/25 (20) 6/47 (13)
 

N.S. N.S.
 

0.638
 

0.184
 

2.421
 

94 90
 

20/25 (80) 46/50 (92)
 

N.S. N.S.
 

1.150
 

0.937
 

1.402
 

86 73
 

High
 

Dose
 

6/49 (12)
 

N.S.
 

0.612
 

0.176
 

2.327
 

105
 

45/50 (90)
 

N.S.
 

1.125
 

0.913
 

1.406
 

86 
Table 4. Analyses of the Incidence of Primary Tumors in Male Rats
 

Administered Diazinon in the Diet (a)
 

(continued)
 

(a) Dosed groups received 400 or 800 ppm.
 

(b) Number of tumor-bearing animals/number of animals examined at site (percent).
 

(c) Beneath the incidence of tumors in the control group is the probability level for the Cochran-


Armitage test when P is less than 0.05; otherwise, not significant (N.S.) is indicated. Beneath
 

the incidence of tumors in a dosed group is the probability level for the Fisher exact test for
 

the comparison of that dosed group with the matched-control group when P is less than 0.05;
 

otherwise, not significant (N.S.) is indicated.
 

(d) A negative trend (N) indicates a lower incidence in a dosed group than in a control group.
 

(e) The probability level for departure from linear trend is given when P is less than 0.05 for any
 

comparison.
 

(f)The 95% confidence interval of the relative risk between each dosed group and the control group.
 
Table 5. Analyses of the Incidence of Primary Tumors in Female Rats
 

Topography ; Morphology
 

Hematopoietic System:
 

Lymphoma or Leukemia (b)
 

P Values (c,d)
 

Relative Risk (f)
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Pituitary: Carcinoma, NOS (b)
 

P Values (c,d)
 

Relative Risk (f)
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Administered Diazinon in the Diet (a)
 

Matched Low
 

Control Dose
 

2/25 (8) 6/50 (12)
 

N.S. N.S.
 

1.500
 

0.297
 

14.521
 

50 81
 

3/25 (12) 3/45 (7)
 

N.S. N.S.
 

0.556
 

0.081
 

3.900
 

68 71
 

High
 

Dose
 

6/50 (12)
 

N.S.
 

1.500
 

0.297
 

14.521
 

1/47 (2)
 

N.S.
 

0.177
 

0.004
 

2.092
 

104
 

49 
Table 5. Analyses of the Incidence of Primary Tumors in Female Rats
 

Administered Diazinon in the Diet (a)
 

(continued) 

Topography: Morphology

Matched 

 Control 

Low 

Dose 

High 

Dose 

Pituitary: Carcinoma, NOS, Adenoma, 

NOS, or Adenocarcinoma, NOS 17/28 (61) 28/45 (62) 23/47 (49) 

P Values (c,d) N.S. N.S. N.S. 

Relative Risk (f) 

Lower Limit 

Upper Limit 

1.025 

0.698 

1.593 

0.806 

0.528 

1.318 

Weeks to First Observed Tumor 68 71 79 

Thyroid: Follicular-cell
 

Adenoma (b) 0/25 (0) 0/47 (0) 3/48 (6)
 

P Values (c,d) N.S. N.S.
 —
 

Relative Risk (f) Infinite
 

Lower Limit 0.321
 

Upper Limit —
 Infinite
 —
 

Weeks to First Observed Tumor 104
 
Table 5. Analyses of the Incidence of Primary Tumors in Female Rats
 

Administered Diazinon in the Diet (a)
 

(continued) 

Topography: Morphology

Matched 

 Control 

Low 

Dose 

High 

Dose 

Thyroid: C-cell Carcinoma or 

Adenoma (b) 0/25 (0) 4/47 (9) 1/48 (2) 

P Values (c,d) N.S. N.S. N.S. 

Relative Risk (f) 

Lower Limit 

Upper Limit 

Infinite 

0.506 

Infinite 

Infinite 

0.029 

Infinite 

Weeks to First Observed Tumor 91 91 

Mammary Gland: Fibroadenoma (b) 5/25 (20) 7/50 (14) 4/50 (8)
 

P Values (c,d) N.S. N.S. N.S.
 

Relative Risk (f) 0.700 0.400
 

Lower Limit 0.217 0.088
 

Upper Limit 2.564 1.716
 

Weeks to First Observed Tumor 104 76 88
 
Table 5. Analyses of the Incidence of Primary Tumors in Female Rats
 

Administered Diazinon in the Diet (a)
 

(continued)
 

Matched Low High
 

Topography! Morphology Control Dose Dose
 

Uterus: Endometrial Stromal
 

Polyp (b) 2/23 (9) 8/43 (19) 11/49 (22)
 

P Values (c,d) N.S. N.S. N.S.
 

Relative Risk (f) 2.140 2.582
 

Lower Limit 0.481 0.637
 

Upper Limit 19.572 22.748
 

Weeks to First Observed Tumor 104 62 72
 

u>
 

(a) Dosed groups received 400 or 800 ppm.
 

(b) Number of tumor-bearing animals/number of animals examined at site (percent).
 

(c) Beneath the incidence of tumors in the control group is the probability level for the Cochran-


Armitage test when P is less than 0.05; otherwise, not significant (N.S.) is indicated. Beneath
 

the incidence of tumors in a dosed group is the probability level for the Fisher exact test for
 

the comparison of that dosed group with the matched-control group when P is less than 0.05;
 

otherwise, not significant (N.S.) is indicated.
 

(d) A negative trend(N) indicates a lower incidence in a dosed group than in a control group.
 

(e) The probability level for departure from linear trend is given when P is less than 0.05 for any
 

comparison.
 

(f) The 95% confidence interval of the relative risk between each dosed group and the control group.
 
IV. RESULTS - MICE
 

A. Body Weights and Clinical Signs (Mice)
 

Mean body weights of the dosed groups of male and female mice
 

were essentially the same as those of the corresponding controls
 

except for the last 20 weeks of the bioassay, when the mean body
 

weights of the dosed females were lower than those of the
 

controls (figure 3). Hyperactivity was reported for the dosed
 

groups of mice but was rare in the control groups.
 

B. Survival (Mice)
 

Estimates of the probabilities of survival for male and female
 

mice administered diazinon in the diet at the doses of this
 

bioassay, together with those for the matched controls, are shown
 

by the Kaplan and Meier curves in figure 4. In each sex, the
 

result of the Tarone test for dose-related trend in mortality is
 

not significant.
 

In male mice, 49/50 (98%) of the high-dose group, 45/50 (90%) of
 

the low-dose group, and 21/25 (84%) of the control group were
 

37
 
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FEMALE MICE 

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TIME ON STUDY (WEEKS) 

Figure 3. Growth Curves for Mice Administered Oiazinon in the Diet 

38 
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TIME ON STUDY (WEEKS) 

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Figure 4.

 30 45 60 75 90

TIME ON STUDY (WEEKS) 

 Survival Curves for Mice Administered Oiazinon in the Diet 

1 5 12 

39 
alive at week 78. In females, 49/50 (98%) of the high-dose 

group, all 50 of the low-dose group, and 24/25 (96%) of the 

control group were alive at week 78. Sufficient numbers of mice 

of each sex were at risk for the development of late-appearing 

tumors. 

C. Pathology (Mice) 

Histopathologic findings on neoplasms in mice are summarized in
 

Appendix B, tables Bl and B2; findings on nonneoplastic lesions
 

are sumnarized in Appendix D, tables Dl and D2.
 

A variety of neoplasms were observed in both dosed and control
 

mice. Most of these were not thought to be compound related.
 

Neoplasms of the liver were seen in an elevated incidence in the
 

low-dose male mice. Hepatocellular adenomas or carcinomas were
 

seen in 5/21 (24%) control, 20/46 (43%) low-dose, and 13/48 (27%)
 

high-dose male mice. The majority of the carcinomas were
 

trabecular carcinomas.
 

A variety of nonneoplastic lesions were seen in dosed and control
 

mice. None appeared to be related to administration of the test
 

chemical.
 

40
 
This histopathologic examination provided no convincing evidence
 

for the carcinogenicity of diazinon in B6C3F1 mice under the
 

conditions of this bioassay. The elevated incidence of liver
 

tumors in the low-dose male mice may have been associated with
 

administration of the test chemical; however, the incidence was
 

lower in the high-dose group than in the low-dose group.
 

D. Statistical Analyses of Results (Mice)
 

Tables 6 and 7 contain the statistical analyses of the incidences
 

of those primary tumors that occurred in at least two animals of
 

one group and at an incidence of at least 5% in one or more than
 

one group.
 

In female mice, the results of the Cochran-Armitage test for
 

dose-related trend in the incidence of tumors and those of the
 

Fisher exact test comparing the incidence of tumors in the
 

control group with that in each dosed group are not significant.
 

In male mice, the Fisher exact test comparing the incidence of
 

hepatocellular carcinomas in the low-dose group with that in the
 

control group shows a P value of 0.046, which is above the 0.025
 

level required for significance when the Bonferroni inequality
 

41
 
criterion is used for multiple comparison. The incidence of
 

these tumors in the high-dose group and the results of the
 

Cochran-Armitage test are not significant. When the incidence of
 

either hepatocellular carcinomas or adenomas in male mice is
 

analyzed, the P values of the statistical tests are above 0.05.
 

In each of the 95% confidence intervals for relative risk, shown
 

in the tables, the value of one is included; this indicates the
 

absence of significant positive results. It should also be noted
 

that each of the intervals has an upper limit greater than one,
 

indicating the theoretical possibility of the induction of tumors
 

by diazinon, which could not be detected under the conditions of
 

this test.
 

42
 
Table 6. Analyses of the Incidence of Primary Tumors in Male Mice
 

Administered Diazinon in the Diet (a)
 

Topography: Morphology


Integumentary System: Fibrosarcoma (b)


P Values (c,d)


Relative Risk (f)
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor


4s
 

U)	 Lung: Alveolar /Bronchiolar Adenoma (b)


P Values (c,d)


Relative Risk (f)
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Matched
 

 Control
 

 1/22 (5)
 

 N.S.
 

 105
 

 2/22 (9)
 

 N.S.
 

105
 

Low
 

Dose
 

1/47	 (2)
 

N.S.
 

0.468
 

0.006
 

35.995
 

105
 

3/47	 (6)
 

N.S.
 

0.702
 

0.088
 

8.025
 

105
 

High
 

Dose
 

3/48	 (6)
 

N.S.
 

1.375
 

0.120
 

70.655
 

103
 

1/48	 (2)
 

N.S.
 

0.229
 

0.004
 

4.219
 

105
 
Table 6. Analyses of the Incidence of Primary Tumors in Male Mice
 

Administered Diazinon in the Diet (a)
 

(continued)
 

Topography: Morphology


Hematopoietic System:
 

Lymphoma or Leukemia (b)


P Values (c,d)


Relative Risk (f)
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor


Liver: Hepatocellular Carcinoma (b)


P Values (c,d)


Departure from Linear Trend (e)


Relative Risk (f)
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Matched Low 

 Control Dose 

 3/22 (14) 7/47 (15) 

 N.S. N.S. 

1.092 

0.283 

6.104 

 83 82 

 4/21 (19) 20/46 (43) 

 N.S. P = 0.046 

 P = 0.009 

2.283 

0.909 

8.187 

83 74 

High
 

Dose
 

7/48 (15)
 

N.S.
 

1.069
 

0.277
 

5.982
 

100
 

10/48 (21)
 

N.S.
 

1.094
 

0.368
 

4.365
 

84 
Table 6. Analyses of the Incidence of Primary Tumors in Male Mice 

Administered Diazinon in the Diet (a) 

(continued) 

Matched Low High 

Topography; Morphology Control Dose Dose 

Liver: Hepatocellular 

Carcinoma or Adenoma (b) 5/21 (24) 20/46 (43) 13/48 (27) 

P Values (c,d) N.S. N.S. N.S. 

Relative Risk (f) 1.826 1.138 

Lower Limit 0.800 0.452 

Upper Limit 5.467 3.653 

Weeks to First Observed Tumor 83 74 84 

.p-
 Ul (a) Dosed groups received 100 or 200 ppm.
 

(b) Number of tumor-bearing animals/number of animals examined at site (percent).
 

(c) Beneath the incidence of tumors in the control group is the probability level for the Cochran-


Armitage test when P is less than 0.05; otherwise, not significant (N.S.) is indicated. Beneath
 

the incidence of tumors in a dosed group is the probability level for the Fisher exact test for
 

the comparison of that dosed group with the matched-control group when P is less than 0.05;
 

otherwise, not significant (N.S.) is indicated.
 

(d) A negative trend(N) indicates a lower incidence in a dosed group than in a control group.
 

(e) The probability level for departure from linear trend is given when P is less than 0.05 for any
 

comparison.
 

(f)The 95% confidence interval of the relative risk between each dosed group and the control group.
 
Table 7. Analyses of the Incidence of Primary Tumors in Female Mice
 

Topography: Morphology


Hematopoietic System:
 

Lymphoma or Leukemia (b)


P Values (c,d)


Relative Risk (f)
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor


Liver: Hepatocellular
 

Carcinoma or Adenoma (b)


P Values (c,d)


Relative Risk (f)
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Administered Diazinon in the Diet (a)
 

Matched Low
 

 Control Dose
 

 3/23 (13) 11/47 (23)
 

 N.S. N.S.
 

1.794
 

0.542
 

9.299
 

 83 94
 

 2/23 (9) 0/47 (0)
 

 N.S. N.S.
 

0.000
 

0.000
 

1.646
 

106
 

High
 

Dose
 

10/49 (20)
 

N.S.
 

1.565
 

0.459
 

8.244
 

103
 

3/49 (6)
 

N.S.
 

0.704
 

0.880
 

8.064
 

103
 
Table 7. Analyses of the Incidence of Primary Tumors in Female Mice
 

Administered Diazinon in the Diet (a)
 

(continued)
 

Matched Low High
 

Topography: Morphology Control Dose Dose
 

Pituitary: Adenoma, NOS (b) 1/13 (8) 1/36 (3) 3/37 (8)
 

P Values (c,d) N.S. N.S. N.S.
 

Relative Risk (f) 0.361 1.054
 

Lower Limit 0.005 0.098
 

Upper Limit 27.594 53.811
 

Weeks to First Observed Tumor 106 105 94
 

*- Mammary Gland: Fibroadenoma (b) 0/23 (0) 1/47 (2) 4/49 (8)
 

P Values (c,d) N.S. N.S. N.S.
 

Relative Risk (f) Infinite Infinite
 

Lower Limit 0.027 0.449
 

Upper Limit Infinite Infinite
 

Weeks to First Observed Tumor 105 94
 
Table 7. Analyses of the Incidence of Primary Tumors in Female Mice
 

Administered Diazinon in the Diet (a)
 

(continued)
 

(a) Dosed groups received 100 or 200 ppm.
 

(b) Number of tumor-bearing animals/number of animals examined at site (percent).
 

(c) Beneath the incidence of tumors in the control group is the probability level for the Cochran-


Armitage test when P is less than 0.05; otherwise, not significant (N.S.) is indicated. Beneath
 

the incidence of tumors in a dosed group is the probability level for the Fisher exact test for
 

the comparison of that dosed group with the matched-control group when P is less than 0.05;
 

otherwise, not significant (N.S.) is indicated.
 

(d) A negative trend(N) indicates a lower incidence in a dosed group than in a control group.
 

(e) The probability level for departure from linear trend is given when P is less than 0.05 for any
 

comparison.
 

(f) The 95% confidence interval of the relative risk between each dosed group and the control group.
 
V. DISCUSSION
 

There was no appreciable effect of administration of diazinon on
 

mean body weights of rats or mice of either sex. Mortality was
 

not increased in any of the dosed groups of rats or mice, and
 

survival was 84% or greater in all dosed and control groups at
 

week 78. Some hyperactivity was observed in dosed groups of both
 

species; however, both the rats and mice may have been able to
 

tolerate higher doses. Sufficient numbers of animals were at
 

risk in all groups for the development of late-appearing tumors.
 

In the male rats, lymphomas or leukemias occurred in the low-dose
 

group at an incidence that was significatly higher (P = 0.011)
 

than that in the control group; however, the incidence of the
 

tumors in the high-dose group was not significant; (controls
 

5/25, low-dose 25/50, high-dose 12/50). In the male mice,
 

hepatocellular carcinomas occurred in the low-dose group at an
 

incidence that was significant at a level of P = 0.046; however,
 

this level is above that of 0.025 required for significance when
 

the Bonferroni inequality criterion is used for multiple
 

comparison. In addition, the incidence of hepatocellular
 

carcinomas in the high-dose group was not significant, (controls
 

4/21, low-dose 20/46, high-dose 10/48), and the incidences of
 

49
 
combined hepatocellular carcinomas and adenomas were not
 

significant by any of the statistical tests used (controls 5/21,
 

low-dose 20/46, high-dose 13/48). Thus, the occurrence of
 

hematopoietic tumors in the male rats and of tumors of the liver
 

in the male mice cannot clearly be related to administration of
 

the test chemical. No tumors occurred at significant incidences
 

by any test in either the female rats or the female mice.
 

In a chronic study previously carried out using diazinon (Bruce
 

et al., 1955), diazinon was administered at 10, 100, or 1,000 ppm
 

in the feed to Carworth Farms albino rats. At 1,000 ppm, initial
 

growth retardation was observed in young rats; however, after 72
 

weeks the other concentrations had no significant effect on
 

consumption of food, gain in body weight, or percentage of
 

survival. The animals were to be carried on study for 2 years;
 

however, the final results of the study are not available.
 

It is concluded that under the conditions of this bioassay,
 

diazinon was not carcinogenic for F344 rats or B6C3F1 mice of
 

either sex.
 

50
 
VI. BIBLIOGRAPHY
 

Armitage, P., Statisitical Methods in Medical Research, John
 

Wiley & Sons, Inc., New York, 1971, pp. 362-365.
 

Ayers, J. H. and Johnson, 0. H., Insecticides. In: Chemical
 

Economics Handbook, Stanford Research Institute, Menlo Park,
 Calif., 1976, sec. 573.3003B and 573.3007G.
 

Bartsch, E., Diazinon, II. Residues in plants, soil, and water.
 

In: Residue Reviews, Gunther, F. A., Ed., Springer-Verlag, New
 

York, 1974, pp. 337-39, 61-62.
 

Berenblum, I., ed., Carcinogenicity Testing; A Report £f the
 

Panel o_f Carcinogenicity of_ the Cancer Research Commission p_f
 

UICC, Vol. 2, International Union Against Cancer, Geneva, 1969.
 

Bruce, R. B., Howard J. W., and Elsea, J. R., Toxicity of
 

0,0-diethyl 0-(2-isopropyl-6-methyl-4-pyrimidyl)phosphorothioate
 

(Diazinon). J. Agric. Fd. Chem. 3(12);1017-1021, 1955.
 

Code of Federal Regulations, 40 CFR 180. L53_, 1976.
 

Cox, D. R., Regression models and life tables. J_._ R^ Statist.
 

Soc. 834:187-220, 1972.
 

Cox D. R., Analysis of Binary Data, Methuen & Co., Ltd., London,
 

1970, pp. 48-52.
 

EPA Compendium of Registered Pesticides, Environmental Protection
 

Agency, Washington, D. C., 1969-1973.
 

Eto, M., Organophosphorus Pesticides; Organic and Biological
 

Chemistry, CRC Press, Inc., Cleveland, Ohio, 1974, pp. 169-170
 

and 248.
 

Gaines, T. B., Acute toxicity of pesticides. Toxicol. Appl.
 

Pharmacol. 14:515-534, 1969.
 

Gart, J. J., The comparison of proportions: a review of
 

significance tests, confidence limits and adjustments for
 

stratification., Rev. Int. Stat. Inst. 39:148-169, 1971.
 

51
 
Kaplan, E. L. and Meier, P., Nonparametric estimation from
 

incomplete observations. J. Amer. Statist. Assoc. 53:457-481,
 

1958.
 

Linhart, M. S., Cooper, J. A., Martin, R. L., Page, N. P., and
 

Peters, J. A., Careinogenesis bioassay data system. Comp. and
 

Biomed. Res. 7^:230-248, 1974.
 

Martin, H. and Worthing, C. R., Diazinon. In: Pesticide Manual,
 

British Crop Protection Council, London, 1977, p. 161.
 

Matsumura, F., Metabolism of insecticides by animals and plants.
 

In: Toxicology £f Insecticides, Plenum Press, New York, 1975,
 

pp. 72, 171, 271, and 462-463.
 

Miller, R. G., Jr., Simultaneous Statistical Inference,
 

McGraw-Hill Book Co., New York, 1966, pp.6-10.
 

Miicke, W., Alt, K. 0., and Esser, H. 0., Degradation of 

l^C-labeled Diazinon in the rat. J_^ Agric. Fd Chem. 

18:208-214, 1970. 

Rossoff, I. S., Diazinon. In: Handbook o_f Veterinary Drugs - A 

Compendium for Research and Clinical Use, Springer Publishing
 

Co., New York~7"l974, P« 162T~
 

Saffiotti, U., Montesano, R., Sellakumar, A. R., Cefis, F., and
 

Kaufman, D. G., Respiratory tract carcinogenesis in hamsters
 

induced by different numbers of administrations of benzo(a)
 

pyrene and ferric oxide. Cancer Res. 32:1073-1081, 1972.
 

Tarone, R. E., Tests for trend in life table analysis.
 

Biometrika 6_2:679-682, 1975.
 

52
 
APPENDIX A
 

SUMMARY OF THE INCIDENCE OF NEOPLASMS IN
 

RATS ADMINISTERED DIAZINON IN THE DIET
 

53
 
54

 
TABLE A1.

 

SUMMARY OF THE INCIDENCE OF NEOPLASMS IN MALE RATS 

ADMINISTERED DIAZINON IN THE DIET 

MATCHED
 

CONTROL LOW DOSE HIGH DOSE
 

ANIMALS INITIALLY IN STUDY 25 50 50
 

ANIMALS NECROPSIED 25 50 50
 

ANIMALS EXAMINED HISTOPATHOLOGICALLY 25 50 50
 

"INTEGUMENTARY SYSTEM
 

XSKIN (25) (50) (50)
 

SQUAMOUS CELL CARCINOMA 1 (2%)
 

TRICHOEPITHELIOMA 1 (2%)
 

*SUBCUT TISSUE (25) (50) (50)
 

FIBROMA 1 (4%) 1 (2%) 1 (2%)
 

FIBROUS HISTIOCYTOMA, MALIGNANT 1 (2%)
 

RESPIRATORY SYSTEM
 

KNASAL MUCOSA (25) (50) (50)
 

CARCINOMA,NOS 1 (2%)
 

SLUNG (24) (48) (49)
 

ALVEOLAR/BRONCHIOLAR ADENOMA 1 (4%) 2 (4%)
 

ALVEOLAR/BRONCHIOLAR CARCINOMA 2 (4%)
 

HEMATOPOIETIC SYSTEM
 

^MULTIPLE ORGANS (25) (50) (50)
 

LEUKEMIA,NOS 5 (20%) 16 (32%) 10 (20%)
 

LYMPHOCYTIC LEUKEMIA 1 (2%)
 

MONOCYTIC LEUKEMIA 6 (12%) 2 (4%)
 

ttLIVER (24) (49) (49)
 

LEUKEMIA,NOS 1 (2%)
 

KPEYERS PATCH (22) (44) (48)
 

MALIGNANT LYMPHOMA, NOS 1 (2%)
 

CIRCULATORY SYSTEM
 

NONE
 

# NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 * NUMBER OF ANIMALS NECROPSIED
 

55
 
TABLE A1. MALE RATS: NEOPLASMS (CONTINUED) 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

DIGESTIVE SYSTEM
 

SSALIVARY GLAND (25) (49) (50)
 

SARCOMA, NOS 1 (2%)
 

#LIVER (24) (49) (49)
 

NEOPLASTIC NODULE 1 (4%) 1 ((2X)
 

HEPATQCELLULAR CARCINOMA 1 I
 

#PANCREAS (25) (47) (49)
 

ACINAR-CELL ADENOMA 2 (4X)
 

#SMALL INTESTINE (22) (44) (48)
 

CARCINOMA,NOS
 

URINARY SYSTEM
 

#KIDNEY (25) (49) (50)
 

LIPOSARCOMA
 

ENDOCRINE SYSTEM
 

8PITUITARY (23) (46) (42)
 

CARCINOMA, NOS 1 (4%)
 

ADENOMA, NOS 8 (35%) 12 (263O 19 (45%)
 

#ADRENAL (24) (49) (48)
 

CORTICAL ADENOMA 1 (2%)
 

PHEOCHROMOCYTOMA 3 (13%) 2 (4*) 2 (4%)
 

GANGLIONEUROMA 2 (4X)
 

#ADRENAL MEDULLA (24) (49) (48)
 

GANGLIONEUROMA 1 (2X)
 

#THYROID (22) (44) (50)
 

FOLLICULAR-CELL ADENOMA 2 (4%)
 

C-CELL ADENOMA 2 (9%) 5 (115<) 4 (8%)
 

C-CELL CARCINOMA 2 (9X) 1 (2X)
 

PAPILLARY CYSTADENOMA, NOS 1 (2%)
 

KPANCREATIC ISLETS (25) (47) (49)
 

ISLET-CELL ADENOMA 5 (20%) 6 (13X) 6 (12%)
 

* NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 * NUMBER OF ANIMALS NECROPSIED
 

56 
TABLE A1, MALE RATS: NEOPLASMS (CONTINUED) 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

REPRODUCTIVE SYSTEM
 

XMAMMARY GLAND (25) cso) (50)
 FIBROADENOMA 2
 

*PREPUTIAL GLAND (25) (50) (50)
 ADENOMA, NOS 1 (2X)
 

STESTIS (25) (50) (50)
 

INTERSTITIAL-CELL TUMOR 20 (802) 46 (92X) <*5 (90X)
 

ttTUNICA ALBUGINEA (25) (50) (50) 

MESOTHELIOMA, NOS 1 (25J)
 

NERVOUS SYSTEM
 

ttBRAIN (25) (50) (50)
 

EPENDYMOMA 1 (2X)
 

SPECIAL SENSE ORGANS
 

NONE
 

MUSCULOSKELETAL SYSTEM
 

NONE
 

BODY CAVITIES
 

XPERITONEUM (25) (50) (50)
 

MESOTHELIOMA BENIGN 1 (2X)
 

*PLEURA (25) (50) (50)
 

MESOTHELIOMA, NOS 1 (23O
 

*TUNICA VAGINALIS (25) (50) (50)
 

MESOTHELIOMA, NOS 1 (25J)
 

ALL OTHER SYSTEMS
 

NONE
 

tt NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 * NUMBER OF ANIMALS NECROPSIED
 

57 
TABLE A1. MALE RATS: NEOPLASMS (CONTINUED) 

ANIMAL DISPOSITION SUMMARY
 

ANIMALS INITIALLY IN STUDY
 

NATURAL DEATHS
 

MORIBUND SACRIFICE
 

*SCHEDULED SACRIFICE
 

ACCIDENTALLY KILLED
 

TERMINAL SACRIFICE
 

ANIMAL MISSING
 

a INCLUDES AUTOLYZED ANIMALS
 

TUMOR SUMMARY
 

TOTAL ANIMALS WITH PRIMARY TUMORS**
 

TOTAL PRIMARY TUMORS
 

TOTAL ANIMALS WITH BENIGN TUMORS
 

TOTAL BENIGN TUMORS
 

TOTAL ANIMALS WITH MALIGNANT TUMORS
 

TOTAL MALIGNANT TUMORS
 

TOTAL ANIMALS WITH SECONDARY TUMORS*
 

TOTAL SECONDARY TUMORS
 

TOTAL ANIMALS WITH TUMORS UNCERTAIN­ BENIGN OR MALIGNANT
 

TOTAL UNCERTAIN TUMORS
 

TOTAL ANIMALS WITH TUMORS UNCERTAIN­ PRIMARY OR METASTATIC
 

TOTAL UNCERTAIN TUMORS
 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

25 50 50 

2 4 1 

9 22 10 

2 2 2 

12 22 37 

25 49 50 

49 1 1 1 106 

24 49 49 

40 78 87 

7 27 16 

8 30 18 

1 3 1 

1 3 1 

Animals are in fact early terminal sacrifices, but appear
 

as scheduled sacrifices due to system interpretation.
 

** PRIMARY TUMORS: ALL TUMORS EXCEPT SECONDARY TUMORS
 

# SECONDARY TUMORS: METASTATIC TUMORS OR TUMORS INVASIVE INTO AN ADJACENT ORGAN
 

58
 
TABLE A2.

 

SUMMARY OF THE INCIDENCE OF NEOPLASMS IN FEMALE RATS 

ADMINISTERED DIAZINON IN THE DIET 

MATCHED 

CONTROL LOW DOSE 

ANIMALS INITIALLY IN STUDY

ANIMALS NECROPSIED

ANIMALS EXAMINED HISTOPATHOLOGICALLY

 25

 25

 25

 50 

 50 

 50 

INTEGUMENTARY SYSTEM
 

XSKIN C25) (50)
 

SQUAMOUS CELL CARCINOMA 1 (2X)
 

FIBROUS HISTIOCYTOMA, MALIGNANT
 

XSUBCUT TISSUE	 (25) (50)
 

FIBROMA
 

RESPIRATORY SYSTEM
 

#LUNG (23) (48)
 

ALVEOLAR/BRONCHIQLAR ADENOMA 1 (4X) 2 (45O
 

ALVEOLAR/BRONCHIOLAR CARCINOMA
 

FIBROUS HISTIOCYTOMA, METASTATIC
 

HEMATOPOIETIC SYSTEM
 

^MULTIPLE ORGANS (25) (50)
 

LEUKEMIA, NOS 1 (4X) 4 (8X)
 

LYMPHOCYTIC LEUKEMIA
 

MONOCYTIC LEUKEMIA 2 (4%)
 

•SPLEEN	 (25) (47)
 

MALIG.LYMPHOMA, HISTIOCYTIC TYPE 1 (4%)
 

OLIVER (24) (48)
 

LEUKEMIA, NOS
 

CIRCULATORY SYSTEM
 

NONE
 

* NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 * NUMBER OF ANIMALS NECROPSIED
 

HIGH DOSE
 

50
 

50
 

50
 

(50)
 

1 (2X)
 

(50)
 

1 (2X)
 

(50)
 

1 (2X)
 

1 (2%)
 

(50)


3 (6%)
 

1 (2%)
 

1 (2%)
 

(50)
 

(50)


1 (2%)
 

59
 
TABLE A2. FEMALE RATS: NEOPLASMS (CONTINUED) 

DIGESTIVE SYSTEM
 

XTONGUE
 

SQUAMOUS CELL PAPILLOMA
 

SSALIVARY GLAND
 

ADENOMA, NOS
 

#LIVER
 

NEOPLASTIC NODULE
 

URINARY SYSTEM.
 

#KIDNEY
 

TUBULAR-CELL ADENOMA
 

ENDOCRINE SYSTEM
 

#PITUITARY
 

CARCINOMA, NOS
 

ADENOMA, NOS
 

ADENOCARCINOMA, NOS
 

«ADRENAL
 

CORTICAL ADENOMA
 

STHYROID
 

FOLLICULAR-CELL ADENOMA
 

C-CELL ADENOMA
 

C-CELL CARCINOMA
 

#PANCREATIC ISLETS
 

ISLET-CELL ADENOMA
 

REPRODUCTIVE SYSTEM
 

XMAMMARY GLAND
 

ADENOMA, NOS
 

PAPILLARY ADENOMA
 

PAPILLARY ADENOCARCINOMA
 

INFILTRATING DUCT CARCINOMA
 

MATCHED
 

CONTROL
 

(25)
 

(25)
 

(24)
 i (4%)
 

(25)
 

(25)


3 (12%)
 

14 (56%)
 

(25)


1 (4%)
 

(25)
 

(25)
 

(25)
 

1 (4%)
 

LOW DOSE
 

(50)


1 (2%)
 

(49)
 

1 (2%)
 

(48)
 

1 (2%)
 

(50)
 

(45)
 

3 (7%)
 

23 (51%)
 

2 (4%)
 

(50)
 

(47)
 

3 (6%)
 

1 (2%)
 

(48)


1 (2%)
 

(50)
 

1 (2%)
 

1 (2%)
 

HIGH DOSE
 

(50)
 

(49)
 

(50)
 

(50)


1 (2X)
 

(47)
 

1 (2%)
 

22 (47%)
 

(49)
 

1 (2%)
 

(48)


3 (6%)
 

1 (2%)
 

(50)


2 (4%)
 

(50)
 

1 (2%)
 

# NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 * NUMBER OF ANIMALS NECROPSIED
 

60
 
TABLE A2. FEMALE RATS: NEOPLASMS (CONTINUED)

 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

FIBROADENOMA 5 (205O 7 ( 14X) 4 (8%)
 

*CLITORAL GLAND (25) (50) (50)
 

CARCINOMA,NOS 1 (25O 1 (25O
 

ttUTERUS (23) (43) (49)
 

ENDOMETRIAL STROMAL POLYP 2 (9X) 8 (19X) 11 (22X)
 

ENDOMETRIAL STROMAL SARCOMA 1 (2X)
 

SOVARY (25) (48) (49)
 

SERTOLI-CELL TUMOR 1 (2X)
 

NERVOUS SYSTEM
 

ttBRAIN (25) (49) (49)
 

EPENDYMOMA 1 (4X)
 

OLIGODENDROGLIOMA 1 (2X)
 

SPECIAL SENSE ORGANS
 

NONE
 

MUSCULOSKELETAL SYSTEM
 

NONE
 

BODY CAVITIES
 

XBODY CAVITIES (25) (50) (50)
 

LIPOMA 1 (2X)
 

^ABDOMINAL CAVITY (25) (50) (50)
 

LIPOMA 1 (2X)
 

ALL OTHER SYSTEMS
 

NONE
 

tt NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 x NUMBER OF ANIMALS NECROPSIED
 

61
 
TABLE A2. FEMALE RATS: NEOPLASMS (CONTINUED) 

ANIMAL DISPOSITION SUMMARY
 

ANIMALS INITIALLY IN STUDY


NATURAL DEATHS)


MORIBUND SACRIFICE


*SCHEDULED SACRIFICE


ACCIDENTALLY KILLED
 

TERMINAL SACRIFICE


ANIMAL MISSING
 

3) INCLUDES AUTOLYZED ANIMALS
 

TUMOR SUMMARY
 

TOTAL ANIMALS WITH PRIMARY TUMORS**
 

TOTAL PRIMARY TUMORS
 

TOTAL ANIMALS WITH BENIGN TUMORS
 

TOTAL BENIGN TUMORS
 

TOTAL ANIMALS WITH MALIGNANT TUMORS
 

TOTAL MALIGNANT TUMORS
 

TOTAL ANIMALS WITH SECONDARY TUMORS*
 

TOTAL SECONDARY TUMORS
 

TOTAL ANIMALS WITH TUMORS UNCERTAIN­ BENIGN OR MALIGNANT


TOTAL UNCERTAIN TUMORS


TOTAL ANIMALS WITH TUMORS UNCERTAIN­ PRIMARY OR METASTATIC
 

TOTAL UNCERTAIN TUMORS
 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

 25 50 50 

1 2 4 

6 18 20 

2 

 16 30 26 

20 44 41 

31 66 59 

16 36 35 

23 50 47 

6 15 12 

7 15 12 

1 

1 

1 1 

1 1 

Animals are in fact early terminal sacrifices, but appear
 

as scheduled sacrifices due to system interpretation.
 

** PRIMARY TUMORS: ALL TUMORS EXCEPT SECONDARY TUMORS
 * SECONDARY TUMORS: METASTATIC TUMORS OR TUMORS INVASIVE INTO AN ADJACENT ORGAN
 

62
 
APPENDIX B
 

SUMMARY OF THE INCIDENCE OF NEOPLASMS IN
 

MICE ADMINISTERED DIAZINON IN THE DIET
 

63
 
64

 
TABLE B1.

 

SUMMARY OF THE INCIDENCE OF NEOPLASMS IN MALE MICE 

ADMINISTERED DIAZINON IN THE DIET 

MATCHED 

CONTROL LOW DOSE 

ANIMALS INITIALLY IN STUDY 

ANIMAL S NECROPSIED 

ANIMALS EXAMINED HISTOPATHOLOGICALLY 

25 

22 

22 

50 

47 

47 

INTEGUMENTARY SYSTEM
 

*SKIN (22) (47)
 

BASAL-CELL CARCINOMA 1 (55O
 

FIBROSARCOMA 1 (25O
 

*SUBCUT TISSUE (22) (47)
 

SARCOMA, NOS 1 (2%)
 

FIBROSARCOMA 1 (55O
 

RESPIRATORY SYSTEM
 

SLUNG (22) (47)
 

HEPATOCELLULAR CARCINOMA, METAST
 

ALVEOLAR/BRONCHIOLAR ADENOMA 2 (95O 3 (650
 

HEMATOPOIETIC SYSTEM
 

^MULTIPLE ORGANS (22) (47)
 

MALIG.LYMPHOMA, LYMPHOCYTIC TYPE 1 (550 3 (6%)
 

LYMPHOCYTIC LEUKEMIA 1 (55O
 

SSPLEEN (22) (47)


MALIG.LYMPHOMA, HISTIOCYTIC TYPE 1 (25O
 

SMESENTERIC L. NODE ( 17) (44)
 

MALIG.LYMPHOMA, LYMPHOCYTIC TYPE 3 (75O
 

MALIG.LYMPHOMA, HISTIOCYTIC TYPE
 

((STOMACH (19) (46)
 

MALIGNANT LYMPHOMA, NOS 1 (5%)
 

CIRCULATORY SYSTEM
 

ttSPLEEN (22) (47)
 

HEMANGIOSARCOMA
 

» NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 x NUMBER OF ANIMALS NECROPSIED
 

HIGH DOSE
 

50
 

48
 

48
 

(48)
 

3 (65O
 

(48)
 

(48)
 

1 (25O
 

1 (250
 

(48)
 

6 (1355)
 

(44)
 

(48)
 

1 (25O
 

(46)
 

(44)
 

1 (2X)
 

65
 
TABLE B1. MALE MICE: NEOPLASMS (CONTINUED) 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

DIGESTIVE SYSTEM
 

8LIVER (21) (46) (48)
 

HEPATOCELLULAR ADENOMA 1 (5X) 3 (6X)
 

HEPATOCELLULAR CARCINOMA 4 (19%) 20 (435O 10 (2U)
 

KDUODENUM (19) (42) (44)
 

CARCINOMA-IN-SITU, NOS 1 (2%)
 

ADENOCARCINOMA, NOS 1 (2X)
 

URINARY SYSTEM
 

NONE
 

ENDOCRINE SYSTEM
 

STHYROID (21) (<t2) (42)
 

PAPILLARY ADENOMA 1 (55O
 

FOLLICULAR-CELL ADENOMA 1 (5X)
 

REPRODUCTIVE SYSTEM
 

NONE
 

NERVOUS SYSTEM
 

NONE
 

SPECIAL SENSE ORGANS
 

*EYE/LACRIMAL GLAND (22) (47) (48)
 

ADENOMA, NOS 1 (5X)
 

.MUSCULOSKELETAL SYSTEM
 

NONE
 

BODY CAVITIES
 

HONE
 

# NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 x NUMBER OF ANIMALS NECROPSIED
 

66
 
TABLE 61. MALE MICE: NEOPLASMS (CONTINUED) 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

ALL OTHER SYSTEMS 

NONE 

ANIMAL DISPOSITION SUMMARY 

ANIMALS INITIALLY IN STUDY 

NATURAL DEATHS 

MORIBUND SACRIFICE 

*SCHEDULED SACRIFICE 

ACCIDENTALLY KILLED 

TERMINAL SACRIFICE 

ANIMAL MISSING 

25 

7 

2 

5 

1 1 

50 

5 

13 

5 

27 

50 

3 

8 

5 

34 

a INCLUDES AUTOLYZED ANIMALS 

TUMOR SUMMARY 

TOTAL ANIMALS WITH PRIMARY TUMORS** 

TOTAL PRIMARY TUMORS 

12 

15 

30 

34 

24 

25 

TOTAL ANIMALS WITH BENIGN TUMORS 

TOTAL BENIGN TUMORS 

6 

6 

3 

3 

4 

4 

TOTAL ANIMALS WITH MALIGNANT TUMORS 

TOTAL MALIGNANT TUMORS 

8 

9 

27 

31 

21 

21 

TOTAL ANIMALS WITH SECONDARY

TOTAL SECONDARY TUMORS 

 TUMORS* 1 

1 

TOTAL ANIMALS WITH TUMORS UNCERTAIN­ BENIGN OR MALIGNANT 

TOTAL UNCERTAIN TUMORS 

TOTAL ANIMALS WITH TUMORS UNCERTAIN­ PRIMARY OR METASTATIC 

TOTAL UNCERTAIN TUMORS 

Animals are in fact early terminal sacrifices, but appear
 

as scheduled sacrifices due to system interpretation.
 

*x PRIMARY TUMORS: ALL TUMORS EXCEPT SECONDARY TUMORS
 * SECONDARY TUMORS: METASTATIC TUMORS OR TUMORS INVASIVE INTO AN ADJACENT ORGAN
 

67
 
TABLE B2. 

SUMMARY OF THE INCIDENCE OF NEOPLASMS IN FEMALE MICE 

ADMINISTERED DIAZINON IN THE DIET 

MATCHED
 

CONTROL LOW DOSE
 

ANIMALS INITIALLC IN STUDY 25 50
 

ANIMALS NECROPSIED 23 47
 

ANIMALS EXAMINED HISTOPATHOLOGICALLY 23 47
 

INTEGUMENTARY SYSTEM
 

*SUBCUT TISSUE (23) (47)
 

LEIOMYOSARCOMA 1 (2%)
 

RESPIRATORY SYSTEM
 

SLUNG (23) (46)


ALVEOLAR/BRONCHIOLAR ADENOMA 1 (4X) 1 (2%)
 

ALVEOLAR/BRONCHIOLAR CARCINOMA
 

HEMATOPOIETIC SYSTEM
 

^MULTIPLE ORGANS (23) (47)


MALIG.LYMPHOMA, LYMPHOCYTIC TYPE i (4*) 8 (17X)
 

MALIG.LYMPHOMA, HISTIOCYTIC TYPE 2 (9X) 2 (4X)
 

GRANULOCYTIC LEUKEMIA 1 (25O
 

ftMESENTERIC L. NODE (22) (38)
 

MALIG.LYMPHOMA, LYMPHOCYTIC TYPE
 

SRENAL LYMPH NODE (22) (38)
 

MALIG.LYMPHOMA, HISTIOCYTIC TYPE
 

KKIDNEY (23) (47)
 

MALIG.LYMPHOMA, HISTIOCYTIC TYPE
 

CIRCULATORY SYSTEM
 

^MULTIPLE ORGANS (23) (47)
 

HEMANGIOSARCOMA
 

ttLIVER (23) (47)
 

HEMANGIOSARCOMA
 

tt NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY 

* NUMBER OF ANIMALS NECROPSIED 

HIGH DOSE
 

50
 

49
 

49
 

(49)
 

(49)
 

1 (2%)
 

1 (2X)
 

(49)


7 (14X)
 

(42)


1 (25O
 

(42)


1 (25O
 

(48)
 

1 (2%)
 

(49)


1 (2X)
 

(49)


1 (2%)
 

68 
TABLE B2. FEMALE MICE: NEOPLASMS (CONTINUED)

 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

DIGESTIVE SYSTEM
 

#LIVER (23) (47) .49)
 

HEPATOCELLULAR ADENOMA 1 (45O 1 (2%)
 

HEPATOCELLULAR CARCINOMA 1 (4X) 2 (4*)
 

URINARY SYSTEM
 

NONE
 

ENDOCRINE SYSTEM
 

SPITUITARY (13) (36) (37)
 

ADENOMA, NOS 1 (8X) 1 (3X) 3 (8%)
 

STHYROID (19) (44) (41)
 

PAPILLARY ADENOCARCINOMA 1 (2X)
 

SPANCREATIC ISLETS (23) (46) (48)
 

ISLET-CELL CARCINOMA 1 (4X)
 

REPRODUCTIVE SYSTEM
 

KMAMMARY GLAND (23) (47) (49)


FIBROADENOMA 1 (2%) 4 (8X)
 

*UTERUS (22) (44) (46)
 

ENDOMETRIAL STROMAL POLYP 1 C2X)
 

SUTERUS/ENDOMETRIUM (22) (44) (46)
 

ADENOMA, NOS 1 (2%)
 

#OVARY (19) (44) (45)
 

GRANULOSA-CELL TUMOR (5X)
 

NERVOUS SYSTEM
 

NONE
 

SPECIAL SENSE ORGANS
 

*EYE/LACRIMAL GLAND (23) (47) (49)
 

ADENOMA, NOS 2 (4%)
 

» NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 * NUMBER OF ANIMALS NECROPSIED
 

69
 
TABLE B2. FEMALE MICE: NEOPLASMS (CONTINUED) 

MATCHED
 

CONTROL LOW DOSE HIGH DOSE
 

'MUSCULOSKELETAL SYSTEM
 

^SKELETAL MUSCLE (23) . (47) (49)
 

FIBROSARCOMA 1
 

BODY CAVITIES
 

NONE
 

ALL OTHER SYSTEMS
 

NONE
 

ANIMAL DISPOSITION SUMMARY
 

ANIMALS INITIALLY IN STUDY 25 50 50
 

NATURAL DEATHS 2 4 2
 

MORIBUND SACRIFICE 2 5 3
 

** SCHEDULED SACRIFICE 5 5 5
 

ACCIDENTALLY KILLED
 1


TERMINAL SACRIFICE 16 36 39
 

ANIMAL MISSING
 

3 INCLUDES AUTOLYZED ANIMALS
 

# NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 * NUMBER OF ANIMALS NECROPSIED
 

** Animals are in fact early terminal sacrifices, but appear
 

as scheduled sacrifices due to system interpretation.
 

70
 
TABLE B2. FEMALE MICE: NEOPLASMS (CONTINUED) 

MATCHED
 

CONTROL LOW DOSE HIGH DOSE
 

TUMOR SUMMARY 

TOTAL ANIMALS WITH PRIMARY TUMORS* 

TOTAL PRIMARY TUMORS 

9 

10 

14 

16 

21 

28 

TOTAL ANIMALS WITH BENIGN TUMORS 

TOTAL BENIGN TUMORS 

3 

3 

4 

<» 10 

12 

TOTAL ANIMALS WITH MALIGNANT TUMORS 

TOTAL MALIGNANT TUMORS 

6 

6 

12 

12 

14 

16 

TOTAL ANIMALS WITH SECONDARY TUMORS* 

TOTAL SECONDARY TUMORS 

TOTAL ANIMALS WITH TUMORS UNCERTAIN­ BENIGN OR MALIGNANT

TOTAL UNCERTAIN TUMORS

 1 

1 

TOTAL ANIMALS WITH TUMORS UNCERTAIN­ PRIMARY OR METASTATIC 

TOTAL UNCERTAIN TUMORS
 

* PRIMARY TUMORS: ALL TUMORS EXCEPT SECONDARY TUMORS
 

3 SECONDARY TUMORS: METASTATIC TUMORS OR TUMORS INVASIVE INTO AN ADJACENT ORGAN
 

71
 
72

 
APPENDIX C
 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS
 

IN RATS ADMINISTERED DIAZINON IN THE DIET
 

73
 
74

 
TABLE C1.

 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS IN MALE RATS 

ADMINISTERED DIAZINON IN THE DIET 

MATCHED
 

CONTROL LOW DOSE HIGH DOSE
 

ANIMALS INITIALLY IN STUDY 25 50 50
 

ANIMALS NECROPSIED 25 50 50
 

ANIMALS EXAMINED HISTOPATHOLOGICALLY 25 50 50
 

INTEGUMENTARY SYSTEM
 

NONE
 

RESPIRATORY SYSTEM
 

#LUNG (24) (48) (49)
 

INFLAMMATION, NOS 1 (2X)
 

BRONCHOPNEUMONIA, ACUTE 1 (23O
 

HEMATOPOIETIC SYSTEM
 

XBLOOD (25) (50) (50)
 

LEUKOCYTOSIS, NOS 1 (2X)
 

SSPLEEN (25) (49) (48)
 

CONGESTION, NOS 6 (12X) 2 (4X)
 

HEMORRHAGE 1 (25O
 

FIBROSIS, FOCAL 1 (2X) 1 (2X)
 

HYPERPLASIA, LYMPHOID 1 (2X)
 

#LYMPH NODE (24) (46) (48)
 

CONGESTION, NOS 1 (2X)
 

SMESENTERIC L. NODE (24) (46) (48)
 

INFLAMMATION, NOS 1 (2X)
 

SPEYERS PATCH (22) (44) (48)
 

HYPERPLASIA, LYMPHOID 1 (2X)
 

CIRCULATORY SYSTEM
 

ttLYMPH NODE (24) (46) (48)
 

LYMPHANGIECTASIS 1 (2X)
 

# NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 x NUMBER OF ANIMALS NECROPSIED
 

75
 
TABLE C1. MALE RATS: NONNEOPLASTIC LESIONS (CONTINUED) 

MATCHED
 

CONTROL LOW DOSE
 

•HEART	 (25) (50)
 

THROMBUS, MURAL	 1 (2%)
 

•AURICULAR APPENDAGE (25) (50)
 

THROMBOSIS, NOS 1 (4X)
 

•MYOCARDIUM	 (25) (50)
 

INFLAMMATION, INTERSTITIAL 2 (45O
 

FIBROSIS, FOCAL 1 (25O
 

•PANCREAS	 (25) (47)
 

PERIARTERITIS 1 (450 2 (450
 

DIGESTIVE SYSTEM
 

•SALIVARY GLAND (25) (49)
 

INFLAMMATION, NOS 1 (25O
 

NECROSIS, NOS 1 (25O
 

•LIVER	 (2*) (49)


NECROSIS, FOCAL 2 (45O
 

NECROSIS, DIFFUSE 1 (25O
 

METAMORPHOSIS FATTY 1 (45O
 

FOCAL CELLULAR CHANGE 1 (45O
 

HYPERPLASIA, NODULAR
 

•LIVER/CENTRILOBULAR	 (24) (49)
 

NECROSIS, DIFFUSE 1 (2JO
 

•BILE DUCT (2*) (49)
 

HYPERPLASIA, NOS 1 (43O 1 (25O
 

•PANCREAS	 (25) (47)
 

INFLAMMATION, NOS 1 (2*)
 

ATROPHY, NOS
 

•PANCREATIC	 ACINUS (25) (47)


ATROPHY, NOS 6 (245O 4 (9X)
 

ATROPHY, FOCAL 1 (2X)
 

•STOMACH	 (24) (48)
 

CYST, NOS
 

ULCER, NOS 2 (4X)
 

# NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 x NUMBER OF ANIMALS NECROPSIED
 

HIGH DOSE
 

(50)
 

(50)
 

1 (250
 

(50)
 

(49)


1 (250
 

(50)
 

(49)
 

1 (25O
 

1 (25O
 

1 (25O
 

(49)
 

(49)
 

(49)
 

1 (2%)
 

(49)


12 (245O
 

(48)


1 (25J)
 

76
 
TABLE C1. MALE RATS: NONNEOPLASTIC LESIONS (CONTINUED) 

MATCHED 

CONTROL LOW DOSE 

CALCIFICATION, DYSTROPHIC 1 (2%) 

ttCECUM 

INFLAMMATION, NOS 

(22) (45) 

1 (2%) 

URINARY SYSTEM
 

((KIDNEY (25) (49)
 

INFLAMMATION, NOS 1 (2%)
 

INFLAMMATION, CHRONIC 15 (60X) 29 (595O
 

CALCIFICATION, DYSTROPHIC 1 (2%)
 

((URINARY BLADDER (22) (41)
 

INFLAMMATION, CHRONIC 1 ( 55O
 

METAPLASIA, SQUAMOUS 1 (5%)
 

ENDOCRINE SYSTEM
 

((PITUITARY (23) (46)
 

CYST, NOS 3 (7X)
 

HYPERPLASIA, FOCAL 1 (2>O
 

((ADRENAL (24) (49)
 

METAMORPHOSIS FATTY 1 (230
 

ANGIECTASIS 1 (230
 

((ADRENAL MEDULLA (24) (49)
 

HYPERPLASIA, NOS
 

((THYROID (22) (44)
 

FOLLICULAR CYST, NOS 1 (25O
 

HYPERPLASIA, C-CELL 1 (23O
 

((PARATHYROID (20) (34)
 

HYPERPLASIA, NOS 1 (35O
 

REPRODUCTIVE SYSTEM
 

((PROSTATE (22) (42)
 

MULTIPLE CYSTS 1 (250
 

INFLAMMATION, CHRONIC 1 (5%)
 

ttTESTIS (25) (50)
 

ATROPHY, NOS 1 (45O 1 (25O
 

(t NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 * NUMBER OF ANIMALS NECROPSIED
 

HIGH DOSE
 

(46)
 

(50)
 

39 (785O
 

(43)
 

(42)
 

1 (25O
 

(48)
 

(48)
 

1 (23O
 

(50)
 

1 (2%)
 

(35)
 

(39)
 

(50)
 

1 (2/O
 

77
 
TABLE C1.MALE RATS: NONNEOPLASTIC LESIONS (CONTINUED) 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

HYPERPLASIA, INTERSTITIAL CELL 1 (45O 1 (2%)
 

NERVOUS SYSTEM
 

#BRAIN (25) (50) (50)
 

HYDROCEPHALUS, NOS 1 (2%)
 

SPECIAL SENSE ORGANS
 

NONE
 

MUSCULOSKELETAL SYSTEM
 

NONE
 

BODY CAVITIES
 

XABDOMINAL CAVITY (25) (50) (50)
 LIPOGRANULOMA 1'
 

ALL OTHER SYSTEMS
 

NONE
 

SPECIAL MORPHOLOGY SUMMARY
 

NO LESION REPORTED 1
 

# NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 * NUMBER OF ANIMALS NECROPSIED
 

78
 
TABLE C2.

 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS IN FEMALE RATS 

ADMINISTERED DIAZINON IN THE DIET 

ANIMALS INITIALLY IN STUDY
 

ANIMALS NECROPSIED
 

ANIMALS EXAMINED HISTOPATHOLOGICALLY
 

INTEGUMENTARY SYSTEM
 

XSUBCUT TISSUE
 

NECROSIS, FAT
 

RESPIRATORY SYSTEM
 

ttLUNG
 

BRONCHOPNEUMONIA, ACUTE
 

INFLAMMATION, ACUTE
 

HYPERPLASIA, ALVEOLAR EPITHELIUM
 

HEMATOPOIETIC SYSTEM
 

*BLOOD
 

LEUKOCYTOSIS, NOS
 

ftSPLEEN
 

CONGESTION, NOS
 

HYPERPLASIA, LYMPHOID
 

ttLYMPH NODE
 

HYPERPLASIA, LYMPHOID
 

ttMESENTERIC L. NODE
 

INFLAMMATION, NOS
 

CIRCULATORY SYSTEM
 

*AURICULAR APPENDAGE
 

THROMBUS, ORGANIZED
 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

25 50 50 

25 50 50 

25 50 50 

(25) (50) (50) 

1 (2%) 

(23) (48) (50) 

2 (4%) 

1 (45O 

1 (2X) 

(25) (50) 

3 (650 

(50) 

3 (6%) 

(25) (47) 

1 (2X) 

(50) 

1 (2%) 

(22) (43) 

1 (2%) 

(47) 

(22) (43) 

1 (2X) 

(47) 

(24) 

1 (4X) 

(48) (50) 

* NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 x NUMBER OF ANIMALS NECROPSIED
 

79
 
TABLE C2. FEMALE RATS: NONNEOPLASTIC LESIONS (CONTINUED) 

MATCHED
 

CONTROL LOW DOSE
 

DIGESTIVE SYSTEM 

((SALIVARY GLAND 

INFLAMMATION, NOS 

(25) (49) 

INFLAMMATION, ACUTE 

SLIVER 

CYST, NOS 

(24) 

1 ( 4/O 

(48) 

INFLAMMATION, PARASITISM  FOCAL GRANULOMATOU 

1 (4X) 

1 (250 

NECROSIS, FOCAL 

METAMORPHOSIS FATTY 

FOCAL CELLULAR CHANGE 

2 (85O 

1

1

 (25O 

 (25O 

SBILE DUCT 

HYPERPLASIA, NOS 

(24) 

1 (450 

(48)

1 (2%) 

((PANCREATIC ACINUS 

ATROPHY, NOS 

(25) 

1 (450 

(48)

4 (8%) 

ttSTOMACH 

INFLAMMATION, ULCER, NOS  NOS 

(23) 

1 (45O 

(47) 

4 (9X) 

URINARY SYSTEM
 

((KIDNEY (25) (50)
 

HYDRONEPHROSIS 1 (2X)
 

INFLAMMATION, NOS 1 (2X)
 

INFLAMMATION, CHRONIC 6 (2450 26 (52X)
 

CALCIFICATION, DYSTROPHIC
 

((URINARY BLADDER (24) (45)
 

HYPERPLASIA, EPITHELIAL
 

METAPLASIA, SQUAMOUS 1 (4X)
 

ENDOCRINE SYSTEM
 

((PITUITARY (25) (45)
 

CYST, NOS 3 (1250 3 (75O
 

MULTIPLE CYSTS
 

HEMORRHAGE
 

# NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 x NUMBER OF ANIMALS NECROPSIED
 

HIGH DOSE
 

(49)


1 (2X)
 

1 (2X)
 

(50)
 

2 (4X)
 

1 (2X)
 

(50)
 

(50)


1 (2X)
 

(49)
 

2 (4JO
 

(50)
 

15 (30X)
 

(48)
 

(47)
 

1 (25O
 

2 (45O
 

1 (250
 

80
 
TABLE C2. FEMALE RATS: NONNEOPLASTIC LESIONS (CONTINUED) 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

ANGIECTASIS

#ADRENAL

NECROSIS, NOS

ANGIECTASIS

*THYROID

HYPERPLASIA, C-CEU

 3 ( 125O

 (25)

1 (4X) 

 (25)

 1 (2%)

 (50)

 (47)

 2 (4X)

 3 (6%) 

 .(49) 

1 (2X) 

 (48) 

2 (45O 

REPRODUCTIVE SYSTEM 

*MAMMARY GLAND

HYPERPLASIA, NOS

KOVARY

CYST, NOS

FOLLICULAR CYST, NOS

 (25)

 (25)

 (50)

 (48)

1 (2X) 

1 (2X) 

­ (50) 

1 (2X) 

 (49) 

NERVOUS SYSTEM 

NONE 

SPECIAL SENSE ORGANS 

NONE 

MUSCULOSKELETAL SYSTEM 

NONE 

BODY CAVITIES 

*BQDY CAVITIES

LIPOGRANULOMA

XABDOMINAL CAVITY

LIPOGRANULOMA

 (25)

 (25)

 (50)

 (50)

3 (6%)

 (50) 

1 (2X) 

 (50) 

1 (2%) 

ALL OTHER SYSTEMS 

NONE 

« NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY x NUMBER OF ANIMALS NECROPSIED 

81
 
TABLE C2. FEMALE RATS: NONNEOPLASTIC LESIONS (CONTINUED) 

MATCHED 

CONTROL LOW DOSE HIGH DOSE — — — — — — — — — — — — — —• — — — — — •— — -- — — — -•• — — ..•'- — — .-— —.—.•,— — »—.-._ — — »__ — — ._—._•._«.—.».._.... — «.».«•_•._-.•._____.•.•.•» — , 

SPECIAL MORPHOLOGY SUMMARY
 

NO LESION REPORTED 1 2 5
 

9 NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

X NUMBER OF ANIMALS NECROPSIED
 

82
 
APPENDIX D
 

SUMMARY OF THE INCIDENCE OF NONNEOPIASTIC LESIONS
 

IN MICE ADMINISTERED DIAZINON IN THE DIET
 

83
 
84

 
TABLE D1.

 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS IN MALE MICE 

ADMINISTERED DIAZINON IN THE DIET 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

ANIMALS INITIALLY IN STUDY

ANIMALS NECROPSIED

ANIMALS EXAMINED HISTOPATHOLOGICALLY

 25 

22 

 22 

50 

47 

47 

50 

48 

48 

INTEGUMENTARY SYSTEM
 

XSKIN (22) (48)
 

INFLAMMATION, CHRONIC
 

INFLAMMATION, GRANULOMATOUS 1 (2%)
 

RESPIRATORY SYSTEM
 

NONE
 

HEMATOPOIETIC SYSTEM
 

^MULTIPLE ORGANS (22) (47) (48)
 

HYPERPLASIA, LYMPHOID 1 (2%)
 

SSPLEEN (22) (47) (44)


SCAR 1 (
 

INFARCT, NOS 1 (2X)
 

HYPERPLASIA, LYMPHOID 1 (5%)
 

ttMESENTERIC L. NODE (17) (44) (48)
 

INFLAMMATION, GRANULOMATOUS 1 (2X)
 

HYPERPLASIA, NOS 1 (2X)
 

SRENAL LYMPH NODE ( 17) (44) (48)


INFLAMMATION, ACUTE 1 (2X)
 

ttlNGUINAL LYMPH NODE ( 17) (44) (48)
 

INFLAMMATION, ACUTE 1 (2%)
 

ftLIVER (21) (46) (48) HEMATOPOIESIS 1 (5%) 

SKIDNEY (22) (47) (47)
 

HYPERPLASIA, LYMPHOID 1 (5%) 1 (2%)
 

» NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 * NUMBER OF ANIMALS NECROPSIED
 

85
 
TABLE 01. MALE MICE: NONNEOPLASTIC LESIONS (CONTINUED) 

MATCHED
 

CONTROL LOW DOSE
 

CIRCULATORY SYSTEM 

#HEART 

INFLAMMATION, ACUTE 

(22)

1 (55O 

(46) 

flHEART/ATRIUM 

THROMBOSIS, NOS 

(22) 

1 (55O 

(46) 

*ARTERY 

PERIARTERITIS 

(22) 

1 (550 

(47) 

8PANCREAS 

PERIARTERITIS 

(21) (46) 

1 (2X) 

DIGESTIVE SYSTEM 

ttLIVER 

INFARCT, NOS 

BASOPHILIC CYTO CHANGE 

FOCAL CELLULAR CHANGE 

(21) 

1 (55O 

(46) 

1 (25O 

1 (2X) 

1 (2X) 

SPANCREAS 

CYSTIC DUCTS 

INFLAMMATION, CHRONIC 

(21) (46) 

1 (25O 

ATROPHY, NOS 1 (2X) 

((STOMACH 

INFLAMMATION, CHRONIC 

(19) (46) 

tfPEYERS PATCH 

HYPERPLASIA, NOS 

(19) (42) 

URINARY SYSTEM 

ttURINARY BLADDER 

HYPERPLASIA, EPITHELIAL 

METAPLASIA, SQUAMOUS 

(20) 

1 (550 

(42) 

1 (2X) 

1 (2X) 

ENDOCRINE SYSTEM 

SADRENAL CORTEX 

HYPERPLASIA, NOS 

(22) (43) 

1 (2X) 

# NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 x NUMBER OF ANIMALS NECROPSIED
 

HIGH DOSE
 

(47)
 

(47)
 

(48)
 

(47)
 

(48)
 

5 (10X)
 

(47)
 

1 (25O
 

(46)


1 (25O
 

(44)
 

1 (2X)
 

(45)
 

(47)
 

86
 
TABLE 01. MALE MICE: NONNEOPLASTIC LESIONS (CONTINUED) 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

#ADRENAL MEDULLA

HYPERPLASIA, NOS

STHYROID

COLLOID CYST

 (22)

 (21)

1 (5X.) 

 (43)

 1 (2%) 

 (42)

 (47) 

 (42) 

REPRODUCTIVE SYSTEM 

XPREPUTIAL GLAND

INFLAMMATION, ACUTE

 (22)

1 (5%)

 (47) (48) 

1 (2%) 

NERVOUS SYSTEM 

NONE 

SPECIAL SENSE ORGANS 

NONE 

MUSCULOSKELETAL SYSTEM 

NONE 

BODY CAVITIES 

NONE 

ALL OTHER SYSTEMS 

NONE 

SPECIAL MORPHOLOGY SUMMARY 

NO LESION REPORTED 6 12

AUTOLYSIS/NO NECROPSY 3 3 

» NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY * NUMBER OF ANIMALS NECROPSIED 

 19 

2 

87
 
TABLE 02.

 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS IN FEMALE MICE 

ADMINISTERED DIAZINON IN THE DIET 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

ANIMALS INITIALLY IN STUDY

ANIMALS NECROPSIED

ANIMALS EXAMINED HISTOPATHOLOGICALLY

 25 

 23 

 23 

50 

47 

47 

50 

49 

49 

INTEGUMENTARY SYSTEM
 

NONE
 

RESPIRATORY SYSTEM
 

SLUNG (23) (46) (49)
 

ATELECTASIS 1 (2X)
 

HEMATOPOIETIC SYSTEM
 

^MULTIPLE ORGANS (23) (47) (49)


HYPERPLASIA, LYMPHOID 7 (30X) 6 (13X) 3 (6X)
 

HEMATOPOIESIS 1 (2X)
 

SSPLEEN (22) (47) (48)
 

CALCIFICATION, DYSTROPHIC 1 (25O
 

HYPERPLASIA, LYMPHOID 2 (9%) 1 (2X)
 

SSPLENIC SINUSOIDS (22) (47) (48)
 

HYPERPLASIA, NOS 1 (5X)
 

#LUNG (23) (46) (49)


HYPERPLASIA, LYMPHOID 1 (2X)
 

UKIDNEY (23) (47) (48)
 

HYPERPLASIA, LYMPHOID 1 (2%) 1 (2%)
 

CIRCULATORY SYSTEM
 

^PULMONARY ARTERY (23) (47) (49)


HYPERTROPHY, NOS 1 (2X)
 

8 NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 x NUMBER OF ANIMALS NECROPSIED
 

88
 
TABLE D2. FEMALE MICE: NONNEOPLASTIC LESIONS (CONTINUED) 

*UTERINE ARTERY
 

THROMBOSIS, NOS
 

DIGESTIVE SYSTEM
 

*LIVER
 

INFLAMMATION, ACUTE
 

GRANULOMA, NOS
 

NECROSIS, FOCAL
 

METAMORPHOSIS FATTY
 

FOCAL CELLULAR CHANGE
 

UCOLON
 

NEMATODIASIS
 

URINARY SYSTEM
 

ttKIDNEY
 

CALCIFICATION, NOS
 

ENDOCRINE SYSTEM
 

SPITUITARY
 

HYPERPLASIA, FOCAL
 

ANGIECTASIS
 

REPRODUCTIVE SYSTEM
 

#UTERUS
 

INFLAMMATION, CHRONIC
 

ttUTERUS/ENDOMETRIUM
 

INFLAMMATION, ACUTE
 

HYPERPLASIA, NOS
 

HYPERPLASIA, CYSTIC
 

UOVARY
 

CYST, NOS
 

NERVOUS SYSTEM
 

NONE
 

MATCHED
 

CONTROL


(23)


(23)


1 (45O
 

1 (45O
 

(22)


(23)


(13)


(22)


1 (550
 

(22)


5 (235O


(19)


 LOW DOSE
 

 (47)
 

 (47)
 

1 (250
 

1 (250
 

 (45)
 

1 (25O
 

 (47)
 

1 (25O
 

 (36)
 

2 (65O
 

 (44)
 

 (44)
 

1 (25O
 

7 (165O
 

1 (25O
 

 (44)
 

4 (95O
 

HIGH DOSE
 

(49)
 

1 (250
 

(49)
 

1 ( 25O
 

1 (25O
 

(45)
 

(48)
 

(37)
 

1 (35O
 

(46)
 

(46)
 

22 (4850
 

(45)
 

2 (455)
 

* NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

X NUMBER OF ANIMALS NECROPSIED
 

89
 
TABLE 02. FEMALE MICE: NONNEOPLASTIC LESIONS (CONTINUED) 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

SPECIAL SENSE ORGANS
 

NONE
 

MUSCULOSKELETAL SYSTEM
 

NONE
 

BODY CAVITIES
 

NONE
 

ALL OTHER SYSTEMS
 

^MULTIPLE ORGANS (23) (47) (49)
 

INFLAMMATION, GRANULOMATOUS 1 (2%)
 

SPECIAL MORPHOLOGY SUMMARY
 

NO LESION REPORTED 6 15 7
 

AUTOLYSIS/NO NECROPSY 2 3 1
 

* NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 * NUMBER OF ANIMALS NECROPSIED
 

90
 
APPENDIX E
 

ANALYSES OF FORMULATED DIETS FOR
 

CONCENTRATIONS OF DIAZINON
 

91
 
92

 
APPENDIX E
 

Analyses of Formulated Diets for
 

Concentration of Diazinon
 

A 10-gram sample of the diet mixture was shaken with 250 mis of
 

benzene at room temperature for 16 hours. A 1-ml aliquot of the
 

resulting benzene solution was removed for analyses. The benzene
 

solution was quantitatively analyzed for diazinon by gas-liquid
 

chromatography (electron capture detector, 10% DC-200 on
 

Gas-Chrom Q column). Recoveries were checked with spiked
 

samples, and external standards were used for calibration.
 

Theoretical Sample Coefficient 

Dietary No. of Analytical of Variation Range 

Level (ppm) Samples Mean (ppm) (%) ( ppm) 

100 15 100.19 5.0 89-110 

200 11 202.54 4.7 194-220
 

400 11 406.12 3.3 389-433
 

800 11 830.47 5.7 791-966
 

93
 
94

 
Review of the Bioassay of Diazinon* for Carcinogenicity
 

by the Data Evaluation/Risk Assessment Subgroup
 

of the Clearinghouse on Environmental Carcinogens
 

December 13, 1978
 

The Clearinghouse on Environmental Carcinogens was established
 

in May, 1976, in compliance with DHEW Committee Regulations and the
 

Provisions of the Federal Advisory Committee Act. The purpose of
 

the Clearinghouse is to advise the Director of the National Cancer
 

Institute on the Institute's bioassay program to identify and evaluate
 

chemical carcinogens in the environment to which humans may be exposed.
 

The members of the Clearinghouse have been drawn from academia, industry,
 

organized labor, public interest groups, and State health officials.
 

Members have been selected on the basis of their experience in carcinogenesis or related fields and, collectively, provide expertise in
 

chemistry, biochemistry, biostatistics, toxicology, pathology, and
 

epidemiology. Representatives of various Governmental agencies participate as ad hoc members. The Data Evaluation/Risk Assessment Subgroup
 

of the Clearinghouse is charged with the responsibility of providing
 

a peer review of reports prepared on NCI-sponsored bioassays of chemicals
 

studied for carcinogenicity. It is in this context that the below critique is given on the bioassay of Diazinon.
 

The reviewer for the report on the bioassay of Diazinon said that
 

the compound was not carcinogenic under the conditions of test. After
 

a brief description of the experimental design, he said that the maximum
 

tolerated doses probably were not tested, as indicated by the lack of
 

weight depression among treated animals. He also noted the poor survival among certain of the animal groups. Because the study was "clearly
 

negative," the reviewer opined that the experimental shortcomings
 

did not invalidate the conclusion. He moved that the report on the
 

bioassay of Diazinon be accepted as written. The motion was seconded
 

and approved without objection.
 

Clearinghouse Members Present;
 

Arnold L. Brown (Chairman), University of Wisconsin Medical School
 

Joseph Highland, Environmental Defense Fund
 

William Lijinsky, Frederick Cancer Research Center
 

Henry Pitot, University of Wisconsin Medical Center
 

Verne A. Ray, Pfizer Medical Research Laboratory
 

Verald K. Rowe, Dow Chemical USA
 

Michael Shimkin, University of California at San Diego
 

95
 
Louise Strong, University of Texas Health Sciences Center
 

Kenneth Wilcox, Michigan State Health Department
 

Subsequent to this review, changes may have been made in the
 

bioassay report either as a result of the review or other reasons.
 

Thus, certain comments and criticisms reflected in the review may
 

no longer be appropriate.
 

•OrU.S. GOVERNMEN T PRINTIN G OFFlCE i 1 97 9-28 I'2 il 7/3 03 I
 

96
 



DHEW Publication No. (NIH) 79-1392