1978 

National Cancer Institute 

CARCINOGENESIS 

Technical Report Series 

No. 33 

BIOASSAY OF 

TETRACHLORVINPHOS 

FOR POSSIBLE CARCINOGEN ICITY 

CAS No. 961-11-5 

NCI-CG-TR-33 

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

Public Health Service 

National Institutes of Health 

BIOASSAY OF
 

TETRACHLORVINPHOS
 

FOR POSSIBLE CARCINOGENICITY
 

Carcinogen Bioassay and Program Resources Branch
 

Carcinogenesis 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
 

DHEW Publication No. (NIH) 78-833
 

BIOASSAY OF
 

TETRACHLORVINPHO S
 

FOR POSSIBLE CARCINOGENICITY
 

Carcinogenesis Program
 

Division of Cancer Cause and Prevention
 

National Cancer Institute
 

National Institutes of Health
 

CONTRIBUTORS; This report presents the results of the bioassay
 

of tetrachlorvinphos for possible carcinogenicity, conducted for
 

the Carcinogen Bioassay and Program Resources Branch, Carcinogenesis Program, Division of Cancer Cause and Prevention, 

National Cancer Institute (NCI), Bethesda, Maryland. The 

bioassay was conducted by Gulf South Research Institute, New
 

Iberia, Louisiana, initially under direct contract to NCI and
 

currently under a subcontract to Tracer Jitco, Inc., prime
 

contractor for the NCI Carcinogenesis bioassay program.
 

The experimental design was determined by Drs. J. H.
 

Weisburger ' and R. R. Bates » , the doses were selected by Drs.
 

T. E. Shellenberger^' , J. H. Weisburger, and R. R. Bates.
 

Animal treatment and observation were supervised by Drs. T. E.
 

Shellenberger and H. P. Burchfield , with the technical
 

assistance of Ms. D. H. Monceaux and Mr. D. Broussard .
 

Histopathology was performed by Drs. E. Bernal^ and B. Buratto^
 

at Gulf South Research Institute, 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 . Statistical analyses were performed
 

by Dr. J. R. Joiner , using methods selected for the bioassay
 

program by Dr. J. J. Gart . Chemicals used in this bioassay were
 

analyzed under the direction of Dr. H. P. Burchfield and the
 

analytical results were reviewed by Dr. S. S. Olin .
 

This report was prepared at Tracer Jitco under the direction of
 

NCI. Those responsible for the report at Tracer Jitco were
 

Dr. Marshall Steinberg , Director of the Bioassay Program;
 

iii
 
Dr. J. F. Robens'', toxicolqgist; Dr. R. L. Schueler?,
 

pathologist; Ms. Y. E. Presley , technical writer; and Dr. E. W.
 

Gunberg , technical editor, assisted by Ms. P. J. Graboske'.
 

The statistical analysis was reviewed by a member or members of
 

the Mathematical Statistics and Applied Mathematics Section of
 

NCI (Dr. John J. Gart, Mr. Jun-mo Nam, Dr. Hugh M. Pettigrew, and
 

Dr. Robert E. Tarone served as reviewers on an alternating
 

basis).
 

The following other scientists at the National Cancer Institute
 

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. Dawn G. Goodman
 

Dr. Richard A. Griesemer
 

Mr. Harry A. Milman
 

Dr. Thomas W. Orme
 

Dr. Robert A. Squire^
 

Dr. Jerrold M. Ward
 

Carcinogenesis Program, Division of Cancer Cause and Prevention,
 

National Cancer Institute, National Institutes of Health,
 

Bethesda, Maryland.
 

^Now with the Naylor Dana Institute for Disease Prevention,
 

American Health Foundation, Hammond House Road, Valhalla,
 

New York.
 

-%ow with the Office of the Commissioner, Food and Drug
 

Administration, Rockville, Maryland.
 

^Gulf South Research Institute, Atchafalaya Basin Laboratories,
 

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

%ow with the National Center for Toxicological Research,
 

Jefferson, Arkansas.
 

iv
 
6

EG&G Mason Research Institute, 1530 East Jefferson Street,
 

Rockville, Maryland.
 

^Tracer Jitco, Inc., 1776 East Jefferson Street, Rockville,
 

Maryland.
 

"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.
 

^Now with the Division of Comparative Medicine, Johns Hopkins
 

University, School of Medicine, Traylor Building, Baltimore,
 

Maryland.
 

v
 

SUMMARY
 

A bioassay of technical-grade tetrachlorvinphos for possible
 

carcinogenicity was conducted by administering the test chemical
 

in feed to Osborne-Mendel rats and B6C3F1 mice.
 

Groups of 50 rats of each sex were administered tetrachlorvinphos
 

at one of two doses for 80 weeks, then observed for 31 additional
 

weeks. Time-weighted average doses were either 4.250 or 8,500
 

ppm. Matched controls consisted of groups of 10 untreated rats
 

of each sex; pooled controls, used for statistical evaluation,
 

consisted of the matched controls combined with 45 untreated male
 

and 45 untreated female rats from similar bioassays of four other
 

test chemicals. All surviving rats were killed at 111 weeks.
 

Groups of 50 mice of each sex were administered tetrachlorvinphos
 

at one of two doses, either 8,000 or 16,000 ppm, for 80 weeks,
 

then observed for 12 additional weeks. Matched controls
 

consisted of groups of 10 untreated mice of each sex; pooled
 

controls, used for statistical evaluation, consisted of the
 

matched controls combined with 40 untreated male and 40 untreated
 

female mice from similar bioassays of four other test chemicals.
 

All surviving mice were killed at 90-92 weeks.
 

The mean body weights of the treated rats and mice were generally
 

lower than those of the matched controls; however, the mortality
 

rate was affected adversely by tetrachlorvinphos only in the male
 

rats. Survival of all groups of rats and mice was adequate for
 

meaningful statistical analyses of the incidence of tumors,
 

except for a matched-control group of female rats for which the
 

survival was abnormally low.
 

In rats, C-cell adenoma of the thyroid showed a significant
 

dose-related trend in the females, using pooled controls
 

(controls 1/46, low-dose 2/50, high-dose 7/46, P = 0.013), and by
 

direct comparison, an increased incidence in the high-dose group
 

(P = Q.Q27), High incidences of C-cell hyperplasia in treated
 

vii
 
males and females further indicated a chemical-related effect on
 

proliferative lesions of the thyroid. Cortical adenoma of the
 

adrenal also showed a significant dose-related trend in the
 

females, using pooled controls (controls 0/50, low-dose 2/49,
 

high-dose 5/50, P = 0.017), and by direct comparison, an
 

increased incidence in the high-dose group (P = 0.022).
 

Hemangioma of the spleen occurred in male rats at a significantly
 

higher incidence in the low-dose group than in the pooled
 

controls (controls 0/52, low-dose 4/48, P = 0.049); however,
 

neither the incidence in the high-dose group (0/47) nor the test
 

result for dose-related trend was statistically significant.
 

In mice, hepatocellular carcinoma in males showed a highly
 

significant dose-related trend, using either matched controls
 

(controls 0/9, low-dose 36/50, high-dose 40/50, P < 0.001) or
 

pooled controls (controls 5/49, P < 0.001). This finding was
 

supported by direct comparisons of low- and high-dose groups of
 

males with matched- or pooled-control groups, which showed highly
 

significant increases in incidences of the tumor in the treated
 

groups in all instances (P < 0.001). In females, the incidence
 

of hepatocellular carcinoma was not significant; however, the
 

incidence of neoplastic nodule was significantly higher in both
 

the low- and high-dose groups than in the pooled controls
 

(controls 1/48, low-dose 14/49, P < 0.001; high-dose 9/47, P =
 

0.007), using pooled controls for tests for both doses. Because
 

of this higher incidence in the low-dose group than in the
 

high-dose group, there was a significant departure from linear
 

trend (P = 0.006).
 

Granulomatous lesions of the liver were found in high proportions
 

in both treated rats and treated mice, but none were found in
 

matched controls.
 

It is concluded that under the conditions of this bioassay, the
 

administration of technical-grade tetrachlorvinphos in
 

Osborne-Mendel rats was associated with proliferative lesions of
 

the C cells of the thyroid and cortical adenomas of the adrenal
 

in females. In female B6C3F1 mice, the incidence of neoplastic
 

nodule of the liver was associated with treatment, and in male
 

mice tetrachlorvinphos was carcinogenic, causing hepatocellular
 

carcinoma of the liver.
 

viii
 
TABLE OF CONTENTS
 

Page
 

I. Introduction	 1
 

II. Materials and Methods	 3
 

A. Chemical	 3
 

B. Dietary Preparation	 4
 

C. Animals	 5
 

D. Animal Maintenance	 5
 

E. Subchronic Studies	 7
 

F. Designs of Chronic Studies	 8
 

G. Clinical and Pathologic Examinations	 11
 

H. Data Recording and Statistical Analyses	 12
 

III. Results - Rats	 17
 

A. Body Weights and Clinical Signs (Rats)	 17
 

B. Survival (Rats)	 17
 

C. Pathology (Rats)	 19
 

D. Statistical Analyses of Results (Rats)	 25
 

IV. Results - Mice	 29
 

A. Body Weights and Clinical Signs (Mice).	 29
 

B. Survival (Mice)	 29
 

C. Pathology (Mice)	 32
 

D. Statistical Analyses of Results (Mice)	 35
 

V. Discussion	 39
 

VI.	 Bibliography 43
 

APPENDIXES
 

Appendix A Summary of the Incidence of Neoplasms in
 

Table Al Summary of the Incidence of Neoplasms in
 

Rats Fed Tetrachlorvinphos in the Diet 45
 

Male Rats Fed Tetrachlorvinphos in the Diet 47
 

Table A2 Summary of the Incidence of Neoplasms in
 

Female Rats Fed Tetrachlorvinphos in the Diet 51
 

ix
 
Page 

Appendix B Summary of the Incidence of Neoplasms in 

Mice Fed Tetrachlorvinphos in the Diet.. 55 

Table Bl Summary of the Incidence of Neoplasms in 

Male Mice Fed Tetrachlorvinphos in the Diet 57 

Table B2 Summary of the Incidence of Neoplasms in 

Female Mice Fed Tetrachlorvinphos in the Diet 60 

Appendix C Summary of the Incidence of Nonneoplastic 

Lesions in Rats Fed Tetrachlorvinphos in the Diet.. 63 

Table Cl Summary of the Incidence of Nonneoplastic 

Lesions in Male Rats Fed Tetrachlorvinphos 

in the Diet 65 

Table C2 Summary of the Incidence of Nonneoplastic 

Lesions in Female Rats Fed Tetrachlorvinphos 

in the Diet 70 

Appendix D Summary of the Incidence of Nonneoplastic 

Lesions in Mice Fed Tetrachlorvinphos 

in the Diet 73 

Table Dl Summary of the Incidence of Nonneoplastic 

Lesions in Male Mice Fed Tetrachlorvinphos 

in the Diet 75 

Table D2 Summary of the Incidence of Nonneoplastic 

Lesions in Female Mice Fed Tetrachlorvinphos 

in the Diet 78 

Appendix E Analyses of the Incidence of Primary Tumors 

in Rats Fed Tetrachlorvinphos in the Diet 81 

Table El Analyses of the Incidence of Primary Tumors 

in Male Rats Fed Tetrachlorvinphos in the Diet 83 

Table E2 Analyses of the Incidence of Primary Tumors 

in Female Rats Fed Tetrachlorvinphos 

in the Diet 88 

x
 
Page 

Appendix F Analyses of the Incidence of Primary Tumors 

in Mice Fed Tetrachlorvinphos in the Diet 93 

Table Fl Analyses of the Incidence of Primary Tumors 

in Male Mice Fed Tetrachlorvinphos in the Diet 95 

Table F2 Analyses of the Incidence of Primary Tumors 

in Female Mice Fed Tetrachlorvinphos 

in the Diet 100 

Appendix G Analysis of Formulated Diets for 

Concentrations of Tetrachlorvinphos 105 

TABLES 

Table 1 Design of Tetrachlorvinphos Chronic Feeding 

Studies in Rats 9 

Table 2 Design of Tetrachlorvinphos Chronic Feeding 

Studies in Mice 10 

FIGURES 

Figure 1 Growth Curves for Rats Fed Tetrachlorvinphos 

in the Diet 18 

Figure 2 Survival Curves for Rats Fed Tetrachlorvinphos 

in the Diet 20 

Figure 3 Growth Curves for Mice Fed Tetrachlorvinphos 

in the Diet 30 

Figure 4 Survival Curves for Mice Fed Tetrachlorvinphos 

in the Diet 31 

xi
 

I. INTRODUCTION
 

Tetrachlorvinphos (CAS 961-11-5; NCI C00168), which is the
 

generic name for 2-chloro-l-(2,4,5-trichlorophenyl)vinyl dimethyl
 

phosphate, is an organophosphorous pesticide introduced in 1966
 

by Shell Development Company (Whetstone et al., 1966). It is
 

registered for use against various pests of fruits, vegetables,
 

ornamental plants, forest trees, and livestock, and for use on
 

agricultural premises, agricultural equipment, and recreational
 

areas (EPA Compendium, 1973). Tetrachlorvinphos was selected for
 

testing in the carcinogenesis program because of its extensive
 

use on food crops and livestock and because there was a lack of
 

chronic toxicity studies of the chemical.
 

1 

II. MATERIALS AND METHODS
 

A. Chemical
 

The material tested was technical-grade tetrachlorvinphos
 

obtained in one batch from Shell Chemical Company, San Ramon,
 

California, for use in the chronic study. As synthesized by the
 

Perkow reaction with trimethyl phosphite and 2,4,5-a , a-pentachloroacetophenone, the compound consists of a- and g-isomers in
 

the ratio of 1 to 9, the former being removed by crystallization
 

(Etc, 1974). The technical product, Gardona®, contains 98%
 

Q
 

p

-isomer, in which the chlorine and phosphate groups are cis.
 

Minimum purity was 94%, according to the manufacturer's
 

specification. It was stored at 4°C in the original glass
 

container.
 

Chemical and physical analyses on the test material were
 

performed at Gulf South Research Institute. Elemental analysis
 

(C, H, Cl, P) was correct for CioH9cl4°4p> the molecular formula
 

of tetrachlorvinphos. Infrared, nuclear magnetic resonance, and
 

mass spectra and thin-layer chromatographic patterns compared
 

well with those of analytical-grade tetrachlorvinphos (99.5%).
 

No attempt was made to identify or quantitate impurities.
 

After completion of the bioassay, Shell Oil Company also analyzed
 

the batch used for the chronic study and found it to be 98.0%
 

3 
pure by quantitative infrared analysis, with 0.014% volatiles.
 

Thus, the chemical retained its purity during the bioassay.
 

B. Dietary Preparation
 

All diets were formulated using finely ground Wayne® Lab Blox
 

(Allied Mills, Inc., Chicago, 111.) to which was added the
 

required amount of tetrachlorvinphos for each dietary concentration. A given amount of the test chemical was first hand-


mixed with an approximately equal amount of feed. This mixture
 

was then added slowly with mechanical mixing to a larger quantity
 

of feed to give the desired concentration of the chemical.
 

Acetone (Mallinckrodt Inc., St. Louis, Mo.) and corn oil
 

(Louana®, Opelousas Refinery Co., Opelousas, La.) were then added
 

to the feed, each in an amount corresponding to 2% of the final
 

weight of feed. The diets were mixed mechanically for not less
 

than 25 minutes to assure homogeneity of the mixture and
 

evaporation of the acetone. Formulated diets were stored at
 

approximately 17°C until used, but no longer than 1 week.
 

The stability of tetrachlorvinphos in feed was tested by
 

determining the concentration of the material in formulated diets
 

at intervals over a 7-day period. Diets containing 8,000 ppm
 

tetrachlorvinphos showed no change on standing at ambient
 

temperature for this period.
 

4 
As a quality control test on the accuracy of preparation of the
 

diets, the concentration of tetrachlorvinphos was determined in
 

different batches of formulated diets during the chronic study.
 

The results are summarized in Appendix G. At each dietary concentration, the mean of the analytical concentrations for the
 

samples tested was within 1.5% of the theoretical concentration,
 

and the coefficient of variation was never more than 5.3%. Thus,
 

the evidence indicates that the formulated diets were prepared
 

accurately.
 

C. Animals
 

Rats and mice of both sexes, obtained through contracts of the
 

Division of Cancer Treatment, National Cancer Institute, were
 

used in these bioassays. The rats were of the Osborne-Mendel
 

strain obtained from Battelle Memorial Institute, Columbus, Ohio,
 

and the mice were B6C3F1 hybrids obtained from Charles River
 

Breeding Laboratories, Inc., Wilmington, Massachusetts. On
 

arrival at the laboratory, all animals were quarantined for an
 

acclimation period (rats for 6 days, mice for 12 days) and were
 

then assigned to control and treated groups.
 

D. Animal Maintenance
 

All animals were housed in temperature- and humidity-controlled
 

rooms. The temperature range was 22-24°C, and the relative
 

5 
humidity was maintained at 40-70%. The air in each room was
 

changed 10-12 times per hour. Fluorescent lighting provided
 

illumination 10 hours per day. Food and water were supplied ad
 

libitum.
 

The rats were housed individually in hanging galvanized steel
 

mesh cages, and the mice were housed in plastic cages with filter
 

bonnets, five per cage for females, and two or three per cage for
 

males. Initially, rats were transferred once per week to clean
 

cages; later in the study, cages were changed every 2 weeks.
 

Mice were transferred once per week to clean cages with filter
 

bonnets; bedding used for the mice was Absorb-Dri (Lab Products,
 

Inc., Garfield, N.J.). For rats, absorbent sheets under the
 

cages were changed three times per week. Feeder jars and water
 

bottles were changed and sterilized three times per week.
 

Cages for control and treated mice were placed on separate racks
 

in the same room. Animal racks for both species were rotated
 

laterally once per week; at the same time, each cage was changed
 

to a different position in the row within the same column. Rats
 

receiving tetrachlorvinphos, along with their matched controls,
 

were housed in a room by themselves. Mice receiving
 

tetrachlorvinphos were maintained in a room housing mice
 

administered dieldrin (CAS 60-57-1) or malathion (CAS 121-75-5),
 

together with their respective matched controls.
 

6 
E. Subchronic Studies
 

Subchronic studies were conducted to determine the maximum
 

tolerated doses of technical-grade tetrachlorvinphos, on the
 

basis of which low and high concentrations (hereinafter referred
 

to as "low doses" and "high doses") were determined for administration in the chronic studies. In these Subchronic studies,
 

tetrachlorvinphos was added to the animal feed in twofold
 

increasing concentrations, ranging from 500 to 8,000 ppm for
 

Osborne-Mendel rats and from 2,000 to 32,000 ppm for B6C3F1 mice.
 

Treated and matched-control groups each consisted of five male
 

and five female animals. The chemical was provided in the feed
 

to the treated groups for 6 weeks, followed by observation for 2
 

weeks. A second study with rats was conducted at dietary
 

concentrations ranging from 4,000 to 32,000 ppm.
 

In both male and female rats, weight depression was apparent at
 

8,000 and 16,000 ppm during the first weeks. Later these animals
 

appeared to adapt to the test chemical, and gains in weight of
 

the treated rats approached those of the controls. There were no
 

deaths in the male rats. One female rat receiving 16,000 ppm
 

died. The low and high doses for rats were set at 8,000 and
 

16,000 ppm for the chronic studies.
 

In mice, males receiving 8,000 ppm or higher initially lost
 

7 
weight; females receiving 16,000 or 32,000 ppm also lost weight
 

at the beginning of the study. Both males and females generally
 

gained or maintained weight during the remainder of the study.
 

No deaths occurred in either sex at any dose tested. The low and
 

high doses for mice were set at 8,000 and 16,000 ppm for the
 

chronic studies.
 

F. Designs of Chronic Studies
 

The designs of the chronic studies are shown in tables 1 and 2.
 

Since the numbers of animals in the matched-control groups were
 

small, pooled-control groups also were used for statistical
 

comparisons. Matched controls from the current studies on
 

tetrachlorvinphos were combined with matched controls from
 

studies performed on malathion, toxaphene (CAS 8001-35-2), endrin
 

(CAS 72-20-8), and lindane (CAS 58-89-9). The pooled controls
 

for statistical tests using rats consisted of 55 males and 55
 

females; using mice, 50 males and 50 females. Studies on
 

chemicals other than tetrachlorvinphos were conducted at Gulf
 

South Research Institute and overlapped the tetrachlorvinphos
 

study by at least 1 year. The matched-control groups for the
 

different test chemicals were of the same strain and from the
 

same supplier, and they were examined by the same pathologists.
 

8 
Table 1. Design of Tetrachlorvinphos Chronic Feeding Studies in Rats
 

Tetrachlor-


Sex and 

Treatment 

Group 

Initial 

No. of 

Animals3 

vinphos 

in Dietb 

(ppm) 

Time o 

Treated 

(weeks) 

n Study 

Untreated0 

(weeks) 

Time-Weighted 

Average Dose 

(ppm) 

Male 

Matched-Control 10 0 111 

Low-Dose 50 8,000 

4,000 

0 

5 

75 

31 

4,250 

High-Dose 50 16,000 

8,000 

0 

5 

75 

31 

8,500 

Female 

Matched-Control 10 0 111 

Low-Dose 50 8,000 

4,000 

0 

5 

75 

31 

4,250 

High-Dose 50 16,000 

8,000 

0 

5 

75 

31 

8,500 

a

All animals were 35 days of age when placed on study.
 

°Doses were lowered at 5 weeks on study, since it was believed that the
 

pattern of deaths, weight gains, and the general condition of the animals
 

in this and other studies indicated that excessive mortality might occur
 

before the end of the study.
 

c

When diets containing tetrachlorvinphos were discontinued, treated
 

animals and matched controls were fed control diets (2% corn oil added).
 

^Time-weighted average dose = Z(dose in ppm x no. of weeks at that dose)
 

I(no. of weeks receiving each dose)
 

9 
Table 2. Design of Tetrachlorvinphos Chronic Feeding Studies in Mice
 

Sex and 

Treatment 

Group 

Initial 

No. of 

Animals3 

Tetrachlorvinphos 

in Diet 

(ppm) 

Time on 

Treated 

(Weeks) 

Study 

Untreatedb 

(Weeks) 

Male 

Matched-Control 10 0 90-92 

Low-Dose 50 8,000 

0 

80 

12 

High-Dose 50 16,000 

0 

80 

12 

Female 

Matched-Control 10 0 90-92 

Low-Dose 50 8,000 

0 

80 

12 

High-Dose 50 16,000 

0 

80 

12 

a

All animals were 35 days of age when placed on study.
 

When diets containing tetrachlorvinphos were discontinued, treated
 

animals and matched controls were fed control diets (2% corn oil added),
 

10
 
G. Clinical and Pathologic Examinations
 

All animals were observed twice daily for signs of toxicity,
 

weighed at regular intervals, and palpated for masses at each
 

weighing. Animals that were moribund at the time of clinical
 

examination were killed and necropsied.
 

The pathologic evaluation consisted of gross and microscopic
 

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

from killed animals and from animals found dead. 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 10% buffered formalin, embedded in
 

paraffin, sectioned, and stained with hematoxylin and eosin.
 

Special staining techniques were utilized when indicated for more
 

definitive diagnosis.
 

A few tissues from some animals were not examined, particularly
 

from those animals that died early. Also, some animals were
 

missing, cannibalized, or judged to be in such an advanced state
 

11
 
of autolysis as to preclude histopathologic evaluation. 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 experiment 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 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
 

12
 
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 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
 

13
 
a control group with that of a group of treated animals at each
 

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

compared simultaneously with those for a control group, a
 

correction to ensure an overall significance level of 0.05 may be
 

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
 

14
 
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
 

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 animals died naturally or were 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 < 0.05, two-tailed test)
 

were also noted.
 

The approximate 95 percent confidence interval for the relative
 

risk of each treated group compared to its control was calculated
 

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

relative risk is defined as Pt/pc where pt is the true binomial
 

probability of the incidence of a specific type of tumor in a
 

15
 
treated group of animals and pc is the true probability of the
 

spontaneous incidence of the same type of tumor in a control
 

group. The hypothesis of equality between the true proportion of
 

a specific tumor in a treated 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 treated 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 treated 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 (a P < 0.025 one-tailed test when the control
 

incidence is not zero, P < 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.
 

16
 
III. RESULTS - RATS
 

A. Body Weights and Clinical Signs (Rats)
 

The mean body weights of the rats fed tetrachlorvinphos were
 

lower than those of the matched controls throughout most of the
 

2-year study (figure 1). The data indicate a dose-related effect
 

on the weights of the males.
 

The treated male rats were generally comparable to the controls
 

in appearance and behavior during the entire study. However, a
 

majority of low-dose and high-dose females had wet and urine-


stained hair coats on their ventral surfaces beginning at week 7;
 

this condition persisted in these groups until termination of the
 

study. At week 28, convulsions were observed in one high-dose
 

female.
 

During the first half of the second year, a moderate incidence of
 

clinical signs including pale mucous membranes, alopecia, rough
 

and discolored hair coats, dyspnea, hematuria, and vaginal
 

bleeding was observed in both groups. These signs increased
 

during the second half of the year.
 

B. Survival (Rats)
 

The Kaplan and Meier curves estimating the probabilities of
 

survival for male and female rats receiving tetrachlorvinphos at
 

17
 
Figure 1. Growth Curves for Rats Fed Tetrachlorvinphos in the Diet
 

18
 
the doses used in this experiment, together with those of the
 

matched controls, are shown in figure 2.
 

In male rats, the Tarone test for positive dose-related trend in
 

mortality over the period of the study had a probability level of
 

0.010, and only 48% of the high-dose group survived to the end of
 

the study. Survival in the low-dose and matched-control groups
 

of males was higher than that in the high-dose group, with 72% of
 

the low-dose and 80% of the matched-control groups living to the
 

end of the study, while only 48% of the high-dose group survived.
 

Early deaths in the high-dose males were not associated with
 

tumors.
 

In female rats, the Tarone test for positive dose-related trend
 

in mortality over the period had a probability level greater than
 

0.05. Survival in the controls was the lowest among the three
 

groups, with only 40% of the controls living to termination of
 

the study, while 82% of the high-dose and 84% of the low-dose
 

groups lived to the end of the study. A sufficient number of
 

treated animals survived for meaningful statistical analyses of
 

the incidence of tumors.
 

C. Pathology (Rats)
 

Histopathologic findings on neoplasms in rats are summarized in
 

19
 
Figure 2. Survival Curves for Rats Fed Tetrachlorvinphos in the Diet
 

20 
Appendix A, tables Al and A2; findings on nonneoplastic lesions
 

are summarized in Appendix C, tables Cl and C2.
 

There was a spontaneous and random occurrence of a variety of
 

neoplasms in both the control and treated groups. Some types of
 

neoplasms occurred only, or with greater frequency, in rats of
 

treated groups compared with controls. These lesions, however,
 

are not uncommon in this strain of rat independent of any
 

treatment.
 

In addition to the neoplastic lesions, a large number of degenerative, proliferative, and inflammatory changes were also encountered in animals of the control and treated groups (Appendix C).
 

For the most part, these nonneoplastic lesions were similar to
 

those commonly seen in aged rats; however, more proliferative
 

changes occurred in the thyroid glands of treated animals than in
 

the thyroid glands of the matched controls. The incidences of
 

these lesions were as follows:
 

21
 
MA LES FEMALES 

Matched Low High Matched Low High 

Control Dose Dose Control Dose Dose 

Number of Tissues
 

Examined (10) (45) (45) (9) (50) (46)
 

Thyroid
 

C-cell Hyperplasia 0 18 8 0 7 16
 

C-cell Adenoma 1 2 3 1 2 7
 

C-cell Carcinoma 0 0 1 0 0 0
 

Follicular-cell
 

Hyperplasia 1 15 14 1 12 12
 

Follicular-cell
 

Adenoma 0 1 0 0 0 1
 

Follicular-cell
 

Carcinoma 0 3 2 0 0 0
 

The C-cell adenomas in the control and treated rats were
 

generally small proliferative nodular lesions which were composed
 

of well differentiated C cells with much cytoplasm, uniform
 

regular nuclei and few mitotic figures. C-cell hyperplasia was
 

mostly a unilateral change which appeared grossly as a slight
 

enlargement of the affected lobe, with a pale-yellow discoloration. Microscopically, there was a fairly uniform, diffuse
 

increase of parafollicular cells ("C" cells) scattered between
 

thyroid follicles. These cells had pale, finely granular
 

cytoplasm and distinct cytoplasmic membranes. Nuclei were round
 

and open with some basophilic granules and distinct nuclear
 

membranes.
 

Follicular-cell hyperplasia was bilateral on several occasions
 

22
 
and appeared grossly as tiny nodular alterations on the thyroid
 

surface. Microscopically, these lesions were quite variable:
 

multifocal and cystic or having inward papillary projections of
 

variable thickness. Follicular epithelial cells lining the projecting fronds were quite regular in appearance. Degenerative
 

changes were few, if any. Colloid production was not a feature.
 

The etiology of the proliferative thyroid lesions in these rats
 

is somewhat equivocal. The incidence of C-cell hyperplasia in
 

low-dose males was more than double that in the high-dose males;
 

the reverse was true in the females, where the incidence in the
 

high-dose group was more than twice that in the low-dose group.
 

Nevertheless, there was a rather large number of animals with the
 

lesion in the treated groups and none in the matched controls.
 

The incidence of follicular-cell hyperplasia seems significant in
 

both the treated and control groups, suggesting spontaneous
 

occurrence. In actual proportions, however, the treated rats had
 

as much as a threefold increase in this change over the controls.
 

The increased incidence of both of these hyperplastic thyroid
 

lesions in rats suggests that these changes may be chemical
 

related. There did not, however, appear to be an increased 

incidence of tumors of either cell type, based on matched 

controls. 

Several adenomas of the adrenal cortex occurred among treated
 

23
 
animals. These adrenal adenomas in both male and female rats
 

were composed of well differentiated cells with abundant
 

eosinophilic cytoplasm, and commonly, there was sinusoidal
 

dilatation and hemorrhage in the tumors.
 

Granulomatous lesions of the liver in rats occurred in 2/50 (4%)
 

low-dose and 14/46 (30%) high-dose males, and in 10/49 (20%) low-


dose and 38/49 (78%) high-dose females, but in no matched-control
 

animals of either sex. The microgranulomas seen in the livers of
 

the rats were randomly and sparsely scattered about the
 

parenchyma; they appeared as microscopic foci not exceeding 50
 

microns in diameter that were made up of a collection of histiocytes and lymphocytes. Gross changes were not evident in these
 

livers. Special stains for microorganisms were used in the
 

livers from a few animals of each sex and group, including
 

controls. These included McManus Periodic Acid Schiff (PAS) and
 

acid-fast stains, and all were negative. The microgranulomatous
 

inflammatory foci in the livers of treated rats seem dose related
 

for both males and females, with a greater incidence in the
 

females than in the males.
 

The results of this histopathologic study indicate that tetrachlorvinphos is responsible in Osborne-Mendel rats for the
 

induction of granulomatous disease in the liver under the
 

conditions of this study.
 

24
 
D. Statistical Analyses of Results (Rats)
 

Tables El and E2 of Appendix E contain the statistical analyses
 

of the incidences of those specific primary tumors that were
 

observed in at least 5% of one or more treated groups of either
 

sex.
 

In male rats, although the Cochran-Armitage test result for
 

positive dose-related trend in proportions for hemangioma of the
 

spleen is not significant at the 0.05 level, there is a
 

significant departure from linear trend due to the higher
 

incidence in the low-dose group than in the high-dose group. The
 

Fisher exact test shows that the incidence in the low-dose group
 

is significantly higher than that in the pooled controls (P =
 

0.049). No such tumor was observed in female rats. The results
 

of the test are inconclusive, however, in that the dose
 

association is apparent in only one treated group, and the level
 

of significance is above the Bonferroni criterion of the 0.025
 

level necessary to establish an error rate of 0.05 throughout the
 

experiment.
 

In female rats, the Cochran-Armitage test result for positive
 

dose-related trend in proportions of animals for cortical adenoma
 

of the adrenal is significant (P = 0.017), using the pooled
 

controls. In addition, the Fisher exact test shows a
 

25
 
significantly higher incidence of this tumor in the high-dose
 

group (P = 0.022) when compared with the pooled controls. The
 

historical record for this bioassay program of this strain of
 

female rats at this laboratory for the incidence of cortical
 

adenoma is 3/240 (1.25%). Using this value as the true parameter
 

of the binomial distribution representing the probability of
 

spontaneous tumors (Fears, 1977), the probability of the
 

occurrence of five or more tumors in the 50 high-dose animals is
 

0.0004, a significant result. The results of tests on the
 

incidence of this tumor in males are not statistically
 

significant.
 

In the analyses of C-cell adenoma of the thyroid in female rats,
 

the Cochran-Armitage test for positive dose-related trend has a
 

probability level of 0.013, using the pooled controls. A
 

positive finding is also established by the Fisher exact test,
 

which shows that the incidence in the high-dose group is
 

significantly higher than that in the pooled controls (P =
 

0.027), implying that the incidence of C-cell adenoma of the
 

thyroid in female rats may be related to treatment. The
 

historical record for this bioassay program of this strain of
 

female rats at this laboratory for the incidence of C-cell
 

adenoma of the thyroid is 8/240 (3.33%). Using this value as the
 

true parameter of the binomial distribution representing the
 

26
 
probability of spontaneous tumors, the probability of the
 

occurrence of seven or more tumors in the 46 high-dose animals is
 

0.0008, a significant result. The statistical conclusion is that
 

an effect has been observed in the high-dose female rats. No
 

C-cell carcinoma was observed in females, and the statistical
 

test results on the combined incidence of C-cell adenoma and
 

carcinoma of the thyroid in males are not statistically
 

significant.
 

In the analyses of chromophobe adenoma of the pituitary in female
 

rats, except for the probability level of 0.021 shown by the
 

Cochran-Armitage test using the matched controls, no other
 

statistical test results are significant in the positive
 

direction.
 

Although the high-dose males died early, time-adjusted analyses
 

were not significant, due to the low incidence of tumors in the
 

high-dose males. There are no other incidences of specific
 

tumors that have statistical significance. When tumors at a
 

single site are grouped (as in follicular-cell adenoma and
 

carcinoma of the thyroid in male rats), the incidences of the
 

individual components of the grouping are not included in tables
 

El and E2 unless they occur in adequate proportions for meaningful statistical analyses; however, a list of the incidences of
 

each type of tumor is provided in tables Al and A2 of Appendix A.
 

27
 

IV. RESULTS - MICE
 

A. Body Weights and Clinical Signs (Mice)
 

The mean body weights of the mice fed tetrachlorvinphos were
 

lower than those of the matched controls throughout the 2-year
 

study (figure 3). The data show dose-related effects on the
 

weights in both the male and female mice.
 

During the first year of the study, the treated animals were
 

generally comparable to the controls in appearance and behavior.
 

A few animals had generalized alopecia. At week 60, a majority
 

of the high-dose males and high-dose females had rough hair
 

coats, which persisted until termination of the study. Other
 

clinical signs appeared in both treated and control groups,
 

including alopecia, rough hair coats, hyperactivity, tachypnea,
 

and abdominal distention. One low-dose female was observed to
 

have convulsions periodically during the second year of the
 

study.
 

B. Survival (Mice)
 

The Kaplan and Meier curves estimating the probabilities of
 

survival for male and female mice receiving tetrachlorvinphos at
 

the doses used in this experiment, together with those of the
 

matched controls, are shown in figure 4. In both sexes, the
 

29
 
Figure 3. Growth Curves for Mice Fed Tetrachlorvinphos in the Diet
 

30
 
Figure 4. Survival Curves for Mice Fed Tetrachlorvinphos in the Diet
 

31 
Tarone test results for dose-related trend in mortality over the
 

period are not statistically significant. Eighty percent of the
 

controls, 78% of. the low-dose males, and 68% of the high-dose
 

males lived to termination of the study.
 

In the females, the survival rate was relatively lower in the
 

controls than in the treated groups. Seventy percent of the
 

controls, 86% of the low-dose females, and 84% of the high-dose
 

females lived to the end of the study. Sufficient numbers of
 

animals of both sexes survived to provide meaningful statistical
 

analyses of the incidence of late-developing tumors.
 

C. Pathology (Mice)
 

Histopathologic findings on neoplasms in mice are summarized in
 

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

are summarized in Appendix D, tables Dl and D2.
 

With the exception of hepatocellular carcinomas and neoplastic
 

nodules, the neoplasms listed in Appendix B appeared with
 

approximately equal frequency in treated and control mice, or
 

appeared in insignificant numbers. Hepatocellular carcinomas and
 

other pertinent lesions of the liver are listed below:
 

32
 
MALES FEMALES 

Matched Low High Matched Low High 

Control Dose Dose Control Dose Dose 

Number of Tissues
 

Examined (9) (50) (50) (9) (49) (47)
 

Liver
 

Hepatocellular
 

carcinoma 0 36 40 0 5 2
 

Neoplastic nodules 0 11 2 0 14 9
 

Granulomatous
 

inflammation 0 50 49 0 48 47
 

The gross appearance of the livers of the treated mice which had
 

hepatocellular carcinoma was markedly altered. Many livers had
 

multinodular growths of small caliber throughout their parenchyma. For the most part, these were tan-red and variegated in
 

pattern with occasional irregular areas of necrosis. The neoplastic nodules were generally single or few in number, seldom
 

larger than 0.5 centimeter in diameter, pale tan, and homogeneous
 

on a cut surface. Granulomatous lesions were often intermingled
 

with the above changes, confusing the gross picture. In cases
 

where granulomatous change existed alone, livers were essentially
 

normal in size, but rubbery in consistency and pale brown. In a
 

few instances, no gross changes were evident.
 

Microscopically, the hepatocellular carcinomas were mostly
 

cellular, pleomorphic-appearing masses of hepatic-like cells
 

devoid of any architectural arrangement, infiltrating the adjoin33
 
ing parenchyma. The number of liver carcinomas within the treated
 

groups of male mice suggests a chemical-related sex predilection
 

for this group. The neoplastic nodules were commonly expanding,
 

well-delineated lesions of regular-appearing liver cells arranged
 

in thickened trabecular and sheet-like growth patterns. Small
 

bile-duct structures were evident within these nodular growths.
 

The neoplastic nodules seen in the mice were considered to be
 

similar to those seen in rats as described by Squire and Levitt
 

(1975).
 

Fewer nonneoplastic lesions (Appendix D) occurred in the mice
 

than in the rats, and except for a granulomatous inflammatory
 

reaction, the lesions were of commonly encountered types. This
 

granulomatous inflammatory reaction occurred in the livers of
 

nearly all of the treated mice, but not in the controls.
 

The granulomatous foci were numerous and randomly distributed
 

throughout the liver parenchyma, with the frequent exception of
 

areas of malignant change. These granulomatous foci were generally 30 to 70 microns in diameter and consisted of aggregations
 

of histiocytes and lymphocytes, with occasional Langhans'-type
 

giant cells. Connective tissue formation was not a histologic
 

feature. The extent of granuloma formation was markedly more
 

severe in the mice than in the rats. Special stains for
 

microorganisms were used on the livers from a few animals of each
 

34
 
sex and group, including controls. These included PAS and
 

acid-fast stains, and all were negative.
 

Widespread microgranuloma formation in the livers of treated mice
 

and the complete absence of this lesion in the control animals
 

implicate tetrachlorvinphos as the inciting cause. The fact that
 

the majority of the mice lived until termination of the study
 

suggests a lesion of slow progression, resulting from extended
 

toxic reaction.
 

The results of this histopathologic study indicate that tetrachlorvinphos is responsible in B6C3F1 mice for the induction of
 

hepatocellular carcinomas, neoplastic nodules, and granulomatous
 

foci in the liver under the conditions of this study.
 

D. Statistical Analyses of Results (Mice)
 

Tables Fl and F2 in Appendix F contain the statistical analyses
 

of the incidences of those specific primary tumors that were
 

observed in at least 5% of one or more treated groups of either
 

sex.
 

The Cochran-Armitage test results for positive dose-related trend
 

in proportions of male mice for hepatocellular carcinoma are
 

significant (P < 0.001), using either matched controls or pooled
 

controls. Also, there are significant departures from linear
 

35
 
trend, with a probability level of 0.003 using the matched
 

controls, and a probability level of 0.002 using the pooled
 

controls. These departures from linearity are due to the steep
 

increases in incidences in the treated groups. The Fisher exact
 

test results for the comparison of the proportions between
 

treated and control groups are also significant (P < 0.001). All
 

of these statistical tests imply a carcinogenic effect of
 

tetrachlorvinphos on the liver in male mice at the doses used in
 

this experiment. The incidence of neoplastic nodule of the liver
 

in low-dose male mice shows a significant result (P = 0.024) by
 

the Fisher exact test when compared with the pooled controls;
 

however, neither the Cochran-Armitage test result nor the Fisher
 

exact comparison of the incidence in the high-dose group with
 

that in the controls is significant. When the occurrences of
 

neoplastic nodule and hepatocellular carcinoma are grouped, the
 

statistical tests show significant results; all of the tests have
 

probability levels of less than or equal to 0.001. The incidence
 

of hepatocellular carcinoma, rather than neoplastic nodule, is
 

primarily responsible for the significance of these grouped
 

results in the male mice.
 

In female mice the reverse is true; neoplastic nodule occurs in
 

significant proportion, but not hepatocellular carcinoma. The
 

Cochran-Armitage test for a positive dose-related trend in the
 

36
 
proportions of neoplastic nodule of the liver has a probability
 

level of 0.018 using the pooled controls. There is an indicated
 

departure from linear trend (P = 0.047 using the matched
 

controls, P = 0.006 using the pooled controls), due to the higher
 

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

Moreover, the Fisher exact test shows significantly higher
 

incidences in the low-dose (P < 0.001) and the high-^dose (P =
 

0.007) groups when compared with the pooled controls. The
 

statistical conclusion is that neoplastic nodule of the liver in
 

female mice is associated with tetrachlorvinphos at the doses
 

used in this experiment.
 

When the liver tumors (neoplastic nodule and hepatocellular
 

carcinoma) in female mice are grouped, the Cochran-Armitage test
 

has a probability level of 0.030 using the pooled controls, with
 

indicated departures from linearity (P = 0.010 using the matched
 

controls, P = 0.002 using the pooled controls), due to the higher
 

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

The Fisher exact test shows that the incidence in the low-dose
 

group is significantly higher than that in either the matched
 

controls (P = 0.020) or the pooled controls (P < 0.001), and the
 

incidence in the high-dose group is significantly higher than
 

that in the pooled controls (P = 0.019). The significance of
 

this grouped incidence is accounted for by the incidence of
 

37
 
neoplastic nodule, and not by that of hepatocellular carcinoma.
 

There are no other specific incidences of tumors in mice of
 

either sex for which the statistical test results are significant
 

in the positive direction.
 

38
 
V. DISCUSSION
 

Tetrachlorvinphos is a member of the organophosphorus group of
 

pesticides that function as neurotoxins by inhibiting cholinesterase (Eto, 1974). The neurotoxicity of tetrachlorvinphos,
 

however, is low in mammals, due to its low solubility in water
 

and in organic solvents, with consequent slow penetration to
 

target areas (Whetstone et al., 1966). In the present bioassay,
 

only one high-dose female rat and one low-dose female mouse
 

showed neurotoxic manifestations.
 

Tetrachlorvinphos is readily detoxified in mammals by metabolic
 

processes involving hydrolysis, reduction, oxidation, and glucuronide formation to yield a variety of products that are excreted
 

mainly in the urine (Akintowa and Hutson, 1967). No reports are
 

available on chronic studies of tetrachlorvinphos.
 

The toxicity of tetrachlorvinphos in the present study was manifested by lower body weights in the treated rats and mice than in
 

the matched controls, and by granulomatous lesions of the liver
 

in both rats and mice. Mortality rates showed a dose-related
 

trend in the male rats, but not in the females; survival in the
 

matched-control females was abnormally low. In mice, dose-


related trends in mortality were not seen in either males or
 

females. Except for the matched-control group of female rats,
 

39
 
the survival of all groups of rats and mice was adequate for
 

meaningful statistical analyses of the incidence of tumors.
 

In rats, the pathologist associated the presence of granulomatous
 

lesions of the liver in both sexes with treatment by
 

tetrachlorvinphos, and special stains showed that there were no
 

microorganisms associated with these lesions. However,
 

significant numbers of hepatic neoplasms in treated animals were
 

not observed. The incidences of C-cell adenoma of the thyroid
 

showed a significant dose-related trend in the females using
 

pooled controls (controls 1/46, low-dose 2/50, high-dose 7/46,
 

P = 0.013), and by direct comparison, an increased incidence in
 

the high-dose group (P = 0.027). Additionally, hyperplasia of
 

the C cells was observed in 7/50 low-dose and 16/46 high-dose
 

female rats, but in no matched-control females and in only one
 

pooled-control female. This further indicated a chemical-related
 

effect on proliferative lesions of the thyroid. In females,
 

there was also a significant dose-related trend in the incidence
 

of adrenal cortical adenoma using pooled controls (controls 0/50,
 

low-dose 2/49, high-dose 5/50, P = 0.017), and by direct comparison, an increased incidence in the high-dose group (P = 0.022).
 

The incidence of this adenoma in the treated groups was also
 

higher than among laboratory historical-control females (3/240).
 

Hemangioma of the spleen occurred at a significantly higher
 

40
 
incidence in the low-dose males than in the corresponding pooled
 

controls, but the association of this tumor with treatment is
 

questionable, since there were only four tumors in the low-dose
 

group and none in the high-dose group, and the test result for
 

dose-related trend was not significant. No other tumor in rats
 

showed a statistically significant incidence.
 

In mice, hepatocellular carcinoma in males showed a highly
 

significant dose-related trend, using either matched or pooled
 

controls (matched controls 0/9, pooled controls 5/49, low-dose
 

36/50, high-dose 40/50, P < 0.001). Direct comparisons of low-


and high-dose groups of males with matched- or pooled-control
 

groups showed highly significant increases in the incidences of
 

the tumor in the treated groups in every case. In female mice,
 

the incidence of hepatocellular carcinoma by itself was not
 

significant. However, the incidence of neoplastic nodule alone
 

(pooled controls 1/48, low-dose 14/49, high-dose 9/47) and in
 

combination with that of hepatocellular carcinoma (pooled
 

controls 3/48, low-dose 19/49, high-dose 11/47) showed
 

significant dose-related trends and also significantly increased
 

rates in low- and high-dose groups using pooled controls. The
 

direct comparison of the combined incidence in the low-dose group
 

was the only comparison with matched controls in females that was
 

significant. There was a significant departure from linear trend
 

41
 
for neoplastic nodule or for combined nodule and carcinoma, since
 

greater numbers were observed in the low-dose than in the
 

high-dose groups. In addition, granulomatous lesions of the
 

liver were observed in all but two of the treated mice, but in
 

none of the matched- or pooled-control animals. Special stains
 

showed that there were no microorganisms associated with these
 

lesions.
 

It is concluded that under the conditions of this bioassay,
 

administration of technical-grade tetrachlorvinphos in Osborne-


Mendel rats was associated with proliferative lesions of the
 

C cells of the thyroid and cortical adenomas of the adrenal in
 

females. In female B6C3F1 mice, the incidence of neoplastic
 

nodule of the liver was associated with treatment, and in male
 

mice tetrachlorvinphos was carcinogenic, causing hepatocellular
 

carcinoma of the liver.
 

42
 
VI. BIBLIOGRAPHY
 

Akintowa, D. A. A. and Hutson, D. H., Metabolism of 2-chloro-l­

(2,4,5-trichlorophenyl)vinyl dimethyl phosphate in dog and
 

rat. J. Agric. Food Chem. 15:632. 1967.
 

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

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

Berenblum, I., ed. , Carcinogenicity Testing; A Report of the
 

Panel of Carcinogenicity of the Cancer Research Commission
 

of UICC. Vol. 2> International Union Against Cancer, Geneva,
 

1969.
 

Cox, D. R., Regression models and life tables. J. R. Statist.
 

Soc. B 34(2);187-220. 1972.
 

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

London, 1970, pp. 48-52.
 

Environmental Protection Agency, EPA Compendium of Registered
 

Pesticides. U. S. Government Printing Office, Washington,
 

B.C., 1973, III-C-29.1-III-C-29.13.
 

Eto, M., Organophosphorus Pesticides; Organic and Biological
 

Chemistry, CRC Press, Cleveland, Ohio, 1974.
 

Fears, T. R., Tarone, R. E., and Chu, K. C., False-positive and
 

false-negative rates for carcinogenicity screens. Cancer
 

Res. 37;1941-1945. 1977.
 

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

significance tests, confidence limits and adjustments for
 

stratification. Rev. Int. Stat. Inst. 39(2);148-169, 1971.
 

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

incomplete observations. J. Am. Statist. Assoc. 53;457-481,
 

1958.
 

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

Peters, J. A., Carcinogenesis bioassay data system. Comp.
 

and Biomed. Res. _7_: 230-248, 1974.
 

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

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

43
 
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.
 

Squire, R. A. and Levitt, M. H., Report on a workshop on 

classification of specific hepatocellular lesions in rats, 

Cancer Res. 35;3214-3223, 1975. 

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

Biometrika 62(3);679-682. 1975.
 

Whetstone, R. R., Phillips, D. D., Sun, Y. P., Ward, L. F. , Jr.,
 

and Shellenberger, T. E. , 2-Chloro-l-(2,4,5-trichlorophenyl)vinyl dimethyl phosphate, a new insecticide with low
 

toxicity to mammals. J. Agric. Food Chem. 14;352, 1966.
 

44
 
APPENDIX A
 

SUMMARY OF THE INCIDENCE OF NEOPLASMS IN
 

RATS FED TETRACHLORVINPHOS IN THE DIET
 

45
 

TABLE A1.

 

SUMMARY OF THE INCIDENCE OF NEOPLASMS IN MALE 

RATS FED TETRACHLORVINPHOS IN THE DIET 

HIGH DOSE 

50 

48 

1»8 

(«8) 

(48) 

t46) 

[48) 

1 (2%) 

(47) 

(«5) 

8NIMAL S INITIALI Y IS STDD Y 

JNTHAL S NECROPSIF D 

fiNIMALS EXAMINE D HISTOPATHOLOGICALLY 

INTEGUMENTAR Y SYSTEH 

*SKIN 

PIBROTIS HISTIOCYT01A 

*SOBCDT TISSUE 

HYXOH A 

HAMARTOM A 

FESPIRATO^Y SYSTEH 

*IONG 

HEPATOCEILOLA R CARCINOBA , HE1AST 

HEHATOPOIETIC SYSTEM 

*HDLTIPLB ORGANS 

MAITG.LYHPHOHA , HTSTIOCYTIC TYPE 

ISPLEEH 

HEBAHGIOH A 

ANGIOH A 

HAHARTON A 

CIRCULATORY SYSTEH 

NONE 

DIGESTIVE SYSTEM 

• SALIVAR Y GLAND 

IDENOCpCINOflA. NOS 

MATCHED 

CONTROL 

10 

10 

10 

(10) 

(10) 

;10) 

;io> 

(10) 

(10) 

LOW DOSE 

50 

50 

50 

(50) 

1 (2%) 

(50) 

1

 [2%) 

1 :2X) 

;50) 

1 (2*) 

!50) 

(H8) 

U (8%) 

1 (2X) 

1 (2%) 

(HI) 

1 (2*) 

« NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NOMBER OF ANIMALS HECHOPSIfD
 

47
 
TABLE A1. MALE RATS: NEOPLASMS (CONTINUED) 

— tt...._...._ ...r.,.,^— ^^.J.—. . _ __. <=.». .1

#LIVER 

NEOPLASTIC NODDLE 

HEPA10CELLULAR CARCINOMA 

*BILE DUCT 

HAM A B TOM A 

URINAR Y SYSTEM 

fKIDNE Y 

TABULAR-CELL ADENOCARCI NOMA 

LTPOS»PCOM S 

HAMARTOM A 

HNDOCBIN E SYSTEM 

tPTTUTTA^ Y 

CHBOHOPHOBE ADENOM A 

ACTDOPHII ADENOH A 

#ADREN?.I 

CORTICAL ADENOM A 

PHEOCHROMOCYTOM K 

fTHYPOT C 

FOLLICUIAR-CELL ADENOM A 

FOLIICULAH-CELL CARCINOMA 

C-CELI ADENOM A 

C-CELL CRHCIUOBR 

tPSNCRl'ATIC ISLETS 

ISLET-CILL ADENO"!* 

TfEPRODUCTIV E SYSTEM 

*MAMMAR Y GLAN D 

CARCINOMA,NO S 

LIPOM A 

tTESTTS 

INTERSTITIAL-CELL TOMCR

 

*FPIDIDY«IS 

„ . LTPQM A „ , . 

. 

MATCHED 

CONTROL 

(10) 

(10) 

;io> 

(9) 

U (UUt) 

(9) 

1 ;11«) 

(10) 

1 ;m%) 

(10) 

;10) 

1 (10%) 

(10) 

(10) 

LOW DOSE HIGH DOSE 

<t 

(50) (HI) 

1 (2*) 1 :2«) 

(50) (U8 )

1 12%) 

[49) in? ) 

1 (2X) 

1 (2%) 1 :2») 

;«3) :37) 

5 (12%) i ;3«> 

(48) (45 ) 

3 (6% ) 1 (2% ) 

(45) (U5 ) 

1 (2%) 

3 ;7%) 2 ;«%), 2 ;u%) 3 ;7%j! 

1 ;2*>i 

(U7) (U6 ) 

2 (US) 

;50) ;u8) 

1 ;2%) 

(U9) («6) 

1 (2%) 

(50) (U8 ) 

„„._„! J2iL . 

I	 NUMBER 0? ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

*	 NUMBER OF ANIMALS NECBOFSIED
 

t This is considered to be a benign form of the malignant mixed tumor
 

of the kidney and consists of lipocytes, tubular structures, and
 

fibroblasts in varying proportions.
 

48
 
TABLE A1. MALE RATS: NEOPLASMS (CONTINUED) 

MATCHED LOW DOSE HIGH DOSE 

CONTROL 

KERVOU S SYSTEM 

*CRANIA L NERV E (10) (50) (U8 ) 

HAMARTOM A 1 (2«) 

SPECIAL SENSE ORGANS 

NON E 

UnSCllLOSKELETAL SYSTEM 

NON E 

EODY CAVITIES 

*PEBTTONSU M (10) (50) (U8 )

 

UESOTHELIOHA , NOS 1 (2*) 

*TUNTCA VAGINfLI S (10) (50) (18) 

HESOTHELTOMA , NO S 1 12%) 2 (H%) 

A L L OTHE P SYSTEM S 

NON E 

ANIHA L DISPOSITIO N SU1CAP Y 

AKIHAL S INTTIftLL Y T N STUDY 10 50 50

 

NATURA L D£ATH a 1 8 7

 

nOHIBUN D SACRIFICE 2 6 21 

SCHECUIE D SACRTFirE 

ACCIDENTALL Y KILLE D 

TERMINA L SACRIFICE 7 36 22

 

»NIHA L HISSING 

3_lfiCLJlB15_MTQI,YZED ^\ N^B ALS_^ 

* NUMBEP OF ANTHALS WI^H TISSUE EXAMINED MICKOSCOPICAIIY
 

* UnnflEB OF ANIMALS NBCECPSIED
 

49
 
TABLE A1. MALE RATS: NEOPLASMS (CONTINUED) 

MATCHED LOW DOSE HIGH DOSE
 

CONTROL
 

TUHOR SUMMARY
 

TOTAL ANIMALS WITH PRIMARY TUMORS* 5 23 15
 

TOTAL FEIHABY TUMORS 7 33 16
 

TOTAL ANIHALS WITH BENIGN TUHCRS 5 19 9
 

TOTAL EINIGN TUMORS 6 24 9
 

TOTAL ANIMALS WITH MALIGNANT TUMORS 1 6 5
 

TOTAI MALIGNANT TUMORS 1 6 5
 

TOTAL ANIMALS WITH SECONDARY TOHORS# 1
 

TOTAL SECONDARY TUMORS 1
 

TOTAL ANIMALS WITH TOMORS ONCERTAINBENIGN OR MALIGNANT 3 2
 

TOTAL UNCERTAIN TUMORS 3 2
 

TOTAL ANIMALS WITH TOHORS UNCERTAINPRIMARY OR METASTATIC
 

TOTAL UNCERTAIN TUMORS
 

* PRIHARY TOHOHS: ALL TOHORS EXCEPT SECONDARY TOHORS
 

I SECONDARY TOHORS: HETASTATIC TOHORS OR TOHORS INVASIVE INTO AH ADJACENT ORGAN
 

50
 
TABLE A2.

 

SUMMARY OF THE INCIDENCE OF NEOPLASMS IN FEMALE 

RATS FED TETRACHLORVINPHOS IN THE DIET 

MATCHED LOW DOSE HIGH DOSE
 

CONTROL
 

8NTMUS INITIALLY IN STDDY 10 50 50
 

SNTMALS NECBOPSIED 9 50 50
 

ANIMALS EXAMINED HI STOFATHOLOGICALLY 9 50 50
 

TNTEGOMENTA*Y SYSTEM
 

*SDBCDT TISSUE (9) (50) (50)


LIPOMA 1 ;2«)
 

BESFIBATOBY SYSTEM
 

HLONG ;9> ;50) ;u9)
 

ALVEOLAB/BBONCHIOLAP CABCINOMA 1 MI*)
 

HEHATOPOIETIC SYSTEM
 

*HOLTIPLE ORGANS (9) (50) (50)
 

HALIG.LYMPHOMA, HISTIOCYTIC TYPE 1 [2%)
 

LYMPHOCYTIC LEOKEMIA 1 J2«)
 

CIFCOLATOBY SYSTEM
 

NONE
 

DIGESTIVE SYSTEM
 

ILIVEH 18) (U9) (50)
 

NFOPLASTIC NODULE 2 (OX)
 

*BILE DOCT 19) (50) (50)
 

BILE DOCT CABCINOMA 1 (2X)
 

HAHARTOHA 2 (•»%) 2 t«X)
 

DBINABY SYSTM
 

HOWE
 

t NDHBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NOMBER OF AHIHALS NECROPSIED
 

51
 
TABLE A2. FEMALE RATS: NEOPLASMS (CONTINUED) 

MATCHED LOW DOSE
 

CONTROL
 

INDOCPINB SYSTEM
 

#PTTOITARY (9) («"»)
 CARCINOMA, NOS
 

ADENOMA, NOS 2 ;s%)
 

CHROMOPHOBE ADENOMA 1 ;2«)
 

#ADFENAL (9) (49)
 

CARCINOMA, NOS 2 (M)
 

CORTICAL ADENOMA 2 ;4X)
 

HTHYPOIE (9) (50)
 

FOLLICOIAR-CELL ADENOMA
 

C-CELL ADENOMA 1 ;11%) 2 ;u«)
 

•PJNCRFATIC ISLETS (9) (48)
 

TSLET-CBLL ADENOMA 1 (2%)
 

*E PRODUCTIVE SYSTEM
 

*M1MMARY GLAND :9> :soj
 

FIBPOMA 1 (11X) 1 (2«)
 

FIBFOADENOMA 3 ;?3%) 4 ;8%)
 

IUTF.PUS (9) (I7

)
 

ENDOMFTRIAL STF.OMAI POLYP 2 (22%) 2 (U%)
 

KOVAFY (8) (49)
 

PAPILLARY ADENOMA
 

PAPTLLAP.Y CYSTADENOMA, NOS
 

GPANOLOSA-CELL TUMOF 1 ;2«)
 

KERVOUS SYSTEM
 

fBHATN J9) ;us)
 

GRANOLAR-CELI TUMOE , BENIGN
 

SPECIAL SENSE ORGANS
 

*EAR CANAL !9) ISO)
 

LEIOMYOMA 1 (11*)
 

MUSCOLOSKILETAL SYSTEM
 

NONE
 

t NUMBER OF ANIMALS HITH TISSUE EXAMINED MICROSCOPICALLY
 * NUMBER OF ANIMALS NECSOPSIED
 

HIGH DOSE
 

(«5)
 

2 («*)
 

7 ;16%)
 

(50)
 

5 ;io«)
 

(16)
 

1 (2%)
 

7 ;15%)
 

C>9)
 

;so)
 

1 (2t)
 

3 ;6%)
 

(HI)
 

1 (2t)
 

(«9)
 

1 (2%)
 

1 ;2%)
 

2 ;«%)
 

;«9)
 

1 (2«)
 

ISO)
 

52 
TABLE A2. FEMALE RATS: NEOPLASMS (CONTINUED) 

BODY CAVITIES
 

NONE
 

ALL OTHER SYSTEMS
 

•MULTIPLE ORGANS
 

FIBROUS HISTIOrY^OMA, MALIGNANT
 

fNIMAL DISPOSITION SUMNABY
 

ANIMALS INITIALLY IN STUDY
 

NATUBAL DEATHS
 

MORIBUND SACRIFICE
 

SCHEDULED SACRIFICE
 

ACCIDENTALLY KILLED
 

TFRNINAL SACRIFICE
 

»NIMAL MISSING
 

3 INCLUDES AUTOLYZED ANIMALS
 

TUMOP SUMMAR Y
 

TOTAL ANIMALS WITH PRIMARY TUMORS*
 

TOTAL PRIMARY TUMORS
 

TOTAL ANIMALS WITH BENIGN TUBOBS
 

TOTAL BENIGN TUMOP.S
 

TOTAL ANIMALS WITH MALIGNANT TUMOBS
 

TO^AL MALIGNANT TUMORS
 

TOTAL ANIMALS WITH SECONDARY TUMORS
 

TOTAL SECONDARY TUHCBS
 

TOTAL ANIMALS WITH TUMORS UNCERTAIN
 

BENIGN OB MALIGNANT
 

TOT»L UNCERTAIN TORCP.S
 

TOTAL ANIMALS WITH TUMC5S UNCERTAIN
 

PRIHAPY OR METASTATIC
 

TO^AL UNCERTAIN TUMCPS
 

MATCHED LOW DOSE HIGH DOSE 

CONTROL 

19) :50) 150) 

1 (2X) 

10 50 50 

1 2 1 

6 7 10 

3 in 39 

7 20 24 

9 23 38 

7 16 23 

8 17 31 

1 3 5 

1 3 5 

* 

-

3 2 

3 2 

* PRIMARY TUMORS: AIL TUMORS EXCEPT SECONDARY TUMORS
 

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

53
 

APPENDIX B
 

SUMMARY OF THE INCIDENCE OF NEOPLASMS IN
 

MICE FED TETRACHLORVINPHOS IN THE DIET
 

55
 

TABLE B1.

 

SUMMARY OF THE INCIDENCE OF NEOPLASMS IN MALE 

MICE FED TETRACHLORVINPHOS IN THE DIET 

MATCHED LOW DOSE
 

CONTROL
 

fNTMALS INITIALLY IN STUDY 10 50
 

fNTMALS NECBOPSTED 9 50
 

JNIMALS EXAMINED HISTOFATHOLOGICALLY 9 50
 

INTIGUBENTASY SYSTEM
 

NONE
 

BESPIRATOPY SYSTEM 

HLONG/BEONCHUS 

CfRCINOMA.NOS 

(8) 

1 (13*) 

(H9) 

*LONG 

ALVEOLAR/BRONCHIOLA5

ALVEOLAR/BRONCHIOtAR

 ADENOBA 

 CARCINOHA 

(8) (49) 

1 (2%) 

3{(,%) 

HEMATOPOIE1IC SYSTEM
 

*MnLTIPLE ORGANS :9) (50)
 

BALIG.IYBPHOBA, LYMPHOCYTIC TYPE 1 (2X)
 

BALIG.LYHPHOHA, HISTIOCYTIC TYPE 1 t2%)
 

GRANDLOCYTIC LEOKEBIA 1 ;11«)
 

tLYBPH NODE (8) C»3)
 

BALIG.LYBPHOBA, HISTIOCYTIC TYPE 1 (2%)
 

CTRCOLATORY SYSTEB
 

NONE
 

DIGESTIVI SYSTEB
 

•LIVZR	 (9) (50)
 

HEOPLASTIC NODULE 11 (22%)
 

HEPATOCELLOLAR CARCINOHA 36 f72X)
 

HEMANGIOM^	 „, -,TM1 Jt2Sl^
 

t NDBBER Of AHIHALS WITH TISSOB EXABINED BICROSCOPICAIIY
 

* NDBBBB OF ANIMALS NECROPSIED
 

HIGH DOSE
 

50
 

5"
 

50
 

(50)
 

(50)
 

2 («)
 

:so)
 

(38)
 

(50)
 

2 (9X)
 

HO ;80%)
 

'
 

57
 
TABLE B1. MALE MICE: NEOPLASMS (CONTINUED) 

MATCHED LOW DOSE HIGH DOSE 

CONTROL 

UBINAF Y SYSTEM 

*KIDNEY ;9) ;50) :so)

HEPATOCEILOLAH CARCINOMA , METAS T 1 (2X) 1 (2«) TUBU1».B-CEIL ADENOCA8CINOMA 1 :2«) 

ENDOCRIN E SYSTEM 

*HDRENA L w :»7) (50) 

CORTICAL CARCINOMA 1 (2X) 

FTPRODOCTTVE SYSTEM 

NONE 

NFRVOOS SYSTEM 

NONE 

SPECIAL SENSE ORGANS 

NONF 

MUSCULOSKELETA1 SYSTEM 

NONE 

BODY CAVITIES 

NONE 

ML OTHER SYSTEMS 

NONE 

I SOMBER OF ABIMULS HTTH TISSUE EXAMINED MICHOSCOPICA11Y
 

* NUMBER OF ANIMALS NECROPSIED
 

58
 
TABLE B1. MALE MICE: NEOPLASMS (CONTINUED) 

fNIPAL DISPOSITION SUMMARY
 

ANIMALS INITIALLY IN STUDY
 

NATURA L DEATHS)
 

MORIBUND SACBIFICE
 

SCHEEUIIC SACRIFICE
 

ACCIDENTALLY RULED
 

TERMINAL SACRIFICE
 

ANIMAL MISSING
 

a INCLUDES AUTOLYZED ANIMALS
 

TOMOR SUMMAR Y
 

TOTAL ANIMALS WITH PRIMARY TUMORS*
 

•TOTAL PRIMARY TUMOFS
 

TOTAL ANIMALS WITH BENIGN TUMCES
 

TO^AL BENIGN TOMORS
 

TOTAL ANIMAL S WITH MALIGNAN T TUMORS
 

TOTAL MALIGNANT TUMORS
 

TOTAT ANIMALS WITH SFCONDARY ^UNORS#
 

TOTAL SECONDARY TUBERS
 

TOTAL ANIMALS WITH TUMOPS UNCERTAINBENIGN OB MALIGNANT
 

TOTAL UNCERTAIN TOMCES
 

TOTPL ANIMALS HITH TUMORS UICER^AINPRTMAR Y OP METASTATIC
 

TOTAL UNCERTAIN TUMORS
 

!	 MATCHED LOW DOSE HIGH DOSE
 

CONTROL
 

10 50	 50
 

2 1 

11 15 

8 39 3U 

2 1*7 H2 

2 56 US 

2 2 

2 2 

2 38 HO 

2 U3 U1 

1 i 

1 1 

11 2 

11 2 

* PC TMRPY TUHORS: ALL TOMOES EXCEPT SECONDfPY TONOBS
 

t SECONDARY TUHOPS: METiSTATTC TOMOBS OR TUMORS INVASIVE INTO AN AEJACENT OFGAH
 

59
 
TABLE B2.

 

SUMMARY OF THE INCIDENCE OF NEOPLASMS IN FEMALE 

MICE FED TETRACHLORVINPHOS IN THE DIET 

8NIBALS INITIAHY IN STUDY
 

JNTBALS NECROPSIED
 

UNIHALS EXABINED HISTOPATHOLOGICALLY
 

TNTEGOBENTARY SYSTEH
 

NONE
 

RESPIRATORY SYSTEH
 

tLUHG
 

ONDIFFERJNTIATED CARCINOHA
 

ALVBOLAB/BRONCHIOLAB ADBNOHA
 

ALVEOLAR/BRONCHIOLAB CABCINOHA
 

HEHATOPOIETIC SYSTEM
 

*«OtTIPLE ORGANS
 

HALIGNANT iYHPHOMA , NOS
 

tMESEHTERTC L. NODE
 

FIBROUS HISTIOCYTOHA
 

ILIVER
 

HALIGNANT LYBPHOHA, NOS
 

CIBCDLATORY SYSTEH
 

NONE
 

DIGESTIVE SYSTEH
 

ttlVER
 

HEOPLASTIC NODDLE
 

HEPATOCEILULAR CARCINOHA
 ^-UaAasiQB^^
 

MATCHED
 

CONTROL
 

910
 

9
 

9
 

(9)
 

:?)
 

0)
 

(9)
 

1 (11*)
 

(9)
 

LOW DOSE
 

50
 

49
 

U9
 

(19)
 

i\ ;sx)
 1 ;2%)
 

;i»9)
 

1 (2%)
 

(39)
 

(«9)
 

(H9)
 

1U (29X)
 

5 J10X)


_2_^asi
 

HIGH DOSE
 

S50
 

HI
 

U7
 

(U7)
 

1 (2%)
 

5 ;m>
 

:i*7)
 

O2)
 

1 (2X)
 

(17)
 

(U7)
 

9 (19*)
 

.______^____ 2 I**)
_
 

t NOHBER OF AHIHALS WITH TISSUE EXAHINED HICROSCOPICALLY
 

* NDMBER OP ANIMALS NECROPSIED
 

9 10 AMI HALS HERE INITIALLY IN STUDY BUT ONE WAS DELETED WHEN FOUND TO BE A HALE
 

ANIHAL IN A FEMALE GBOUP.,
 

6 3'0 ANIHALS HERE INITIALLY IN STUDY BUT ONE »AS DELETED BHEN FOUND It BE A HALE
 

ANIHAL IN A FEHALB GBOUP.
 

60
 
TABLE B2. FEMALE MICE: NEOPLASMS (CONTINUED) 

MATCHED LOW DOSE HIGH DOSE 

CONTROL 

ORIIJARY SYSTEH 

•KIDNEY (9) (49) (U6)

 

TOBULAR-CELL ADENOM A 1 (2%)

 

ENDOCRINE SYSTEH 

IPITUTTAHY 15) ;i»5> ;39) 

CWOMOPHOBE ADENOM A 1 (2«)

 

fTHYSOTD (5) (46) («1)

POLL1COLH.R-CELL ADENOM A 1 (2«) 

REPPODUCTTV E SYSTEM 

*M*MMAR Y GLAN D ;<») ;u9) :«?) 

ABENOCABCINOMA , NO S 1 (2%) 

tDTTP.US (8) (HI) (39) 

ADENOC'\t'CINOMA , NOS 1 (3%) 

1EIOBYOHA 1 [3*) 

tOVA°Y (8) (1»7) (UU ) 

GFANULOSA-CELL TOMOP 1 (2%) 

NFRVOO S SYSTEM 

NONE 

SPECIAL S?NSF OPGANS 

MOVE 

SOSCOIOSKE1ETA1 SYSTEM 

NONE 

E"DY C'VITI^S 

NON E 

* NUMBS? OF ANIMALS «TTH TISSUE EXAMINED MICHOSCOPICA LLY
 

* NUHBE" OF ANIMALS NECROPSIED
 

61
 
TABLE B2. FEMALE MICE: NEOPLASMS (CONTINUED) 

MATCHED LOW DOSE HIGH DOSE
 

CONTROL
 

MI OTHER SYSTEMS
 

NONE
 

ANIMAI DISPOSITION SUMMABY
 

ANIMALS INITIALLY IN STUDY 10 50 50
 

NATUBiL DEATHS
 

MORIBUND SACRIFICE
 

SCHEDULED SACRIFICE
 

ACCIDENTALLY KILLED
 

TEBMINAL SACRIFICE
 

ANIMAL MISSING
 

ANIMAL DELETED/WBONG SEX
 

3 INCLUDES AUTOLYZED ANIMALS
 

TUMOR SOHMAPY
 

TOTAL ANIMALS HITH PRIMARY "'UMORS*
 

TOTAL PRIMARY TOMOPS
 

TOTAL ANIMALS WITH BENIGN TUMORS
 

TO^AL BENIGN TUMOBS
 

TOTAL ANIMALS WITH MALIGNANT TUMOBS
 

TOTAL MALIGNANT TUMORS
 

TOTAL ANIMALS WITH SECONDARY TDMOBSI 1
 

TOTAL SECONDARY TOMCES
 

TOTAL ANIMALS HITH TDHORS UNCERTAINBESIGN OR MALIGNANT
 

TOTAL UNCERTAIN TUMOBS
 

TOTAL ANIMALS WITH TUMORS UNCERTAINPRIMARY OB HETASTATIC
 

TOTAL UNCERTAIN TUMORS
 

2 2
 

2 i* 6
 

7 41 «1
 

1 1
 

1 25 19
 

1 30 22
 

8 6
 

8 8
 

1 8 U
 

1 8 U
 

H 10
 

1« 10
 

* PRIMARY TUMORS: ALL TDHORS EXCEPT SECONDARY TUMORS
 

I SECONDARY TUMORS: HETASTATIC TDMORS OR TUMORS INVASIVE INTO AN ADJACENT ORGAN
 

62
 
APPENDIX C
 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS
 

IN RATS FED TETRACHLORVINPHOS IN THE DIET
 

63
 

TABLE C1.

 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS IN 

MALE RATS FED TETRACHLORVINPHOS 

— — *- «_»—— —_.— — -___-—j 1— ...__-,. -_-„ UB-rra TM-l- -»•».—•—.
 

MATCHED 

CONTROL 

LOW DOSE 

fNIMALS INITIALLY IS STUDY 

ANIMALS NECROPSIED 

ANIMALS EXAMINED HI STOPATHOLOGICALLY 

10 

10 

10 

50 

50 

50 

INTF.GUMEN1APY SYSTEM
 

•SKIN	 (10) (50)
 

GRANTJLOMA, NOS 1 ;2%)
 

GRANULATION, TISSUE 1 t2%)
 

RESPIRATORY SYSTEM
 

#1 IING ;10) -.50)
 

CONGESTION, NOS 1 (2%)
 

EDEMA, NOS
 

CALCIFICATION, HET« STATIC i ;««)
 

*L ING/ ALVEOLI (10) (50)
 

EMPHYSEMA, NOS
 

CALCIFICATION, METASTATIC 1 ;2%)
 

HEMATOPOTETIC SYSTEM
 

tBONE MAEFOW ;io> ;n9)
 

HYPEPPIASIA, NOS 1 (2%)
 

ISPLEEN (10) (IS)
 

FIBPOSIS, FOCAL 1

 (2%)
 

HEMOSIDEROSIS
 1 :2«>
 

#MEDIASTINAL I. NODE (9) (42)
 

INFLAMMATION, CHRONIC 1 (2%)
 

CIRCDLAT05Y SYSTEM
 

•HEART	 ;10) •49)
 

THROMBUS, ORGANIZED 1 (2%)
 

FIBROSIS, FOCAL
 

CALCIFICATION^ METASTATIC - __3_:6«i__TM


I NOMBHR OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMBER OF ASIMALS NECFCPSIED
 

HIGH DOSE
 

50
 

U8
 

HQ
 

(U8)
 

;U6)
 

1 ;2%)
 

(U6)
 

1 (2%)
 

2 ;«%)
 

;U6)
 

(U7)
 

(U1)
 

:u?)
 

1 ;2%)
 

^-l_mi..
 

65
 
TABLE C1. MALE RATS: NONNEOPLASTIC LESIONS (CONTINUED) 

MATCHED LOW DOSE HIGH OOSE
 

CONTROL
 

INYOCARDTOH ;io> ;i»9) [HI]
 

FIBROSIS 1 (2*)
 

FIBROSI?, FOCAL 8 ;16X) 6 ;13X)
 

FIBROSIS, DIFFUSE	 1 ;2%)
 

CALCIFICATION, METf STATIC	 2 ^X)
 

•ENDOCARDIUM	 (10) (1*9) (U7)
 

FTSROSIS 1 (2*)
 

FT3ROSIS, FOCAL 1 ;2X)
 

*AORT» (10) (50) (i*8)
 

1EDIAT. CALCIFICATION
 2' :<*%> 9 ;19X)
 

*CORONAPY 1P.TE"Y	 (10) (50) (U8)
 

1EDIAL CALCIFICATION	 1 ;2%) 3 J6X)
 

"LINGUAL ARTERY (10) (50) (U8)
 

MEDIAL CALCIFICATION 1 ;2«) 1 ;2X)
 

*SPLENIC ARTEPY	 (10) (50) (U8)
 

F7BPOSI?, FO'.AI	 1 ;2%)
 

MEDIAL -CALCIFICATION	 1 (21) 2 ;tx)
 

*MESENTRTC ARTERY (10) (50) («8)
 

MEDIAt CALCIFICATTON 2 ;<»«) 3 ;6X)
 

DIGESTIVE SYSTEM
 

*LIVER ;iO) ISO) ;i»7)
 

INFLAMWATICN, CHRONIC FCCf.L 1 12*)
 

INFLAMMATION, GRANOLCMATOOS 2 ;a%> 17 ;36X)
 

GPANDLOMA, NOS
 

1

 ;2%)
 

FIBPOSIS, FOCAL	 i ;2«)
 

CIRRHOSIS, NOS	 1 :2«j
 

NECROSIS, FOCAL	 1 ;2%>
 

METAMORPHOSIS FATTY	 a ;s«) 15 ;32X)
 

CALCIFICATION, NOS	 1 ;2X)
 

HENOSIDEPOSIS	 1 ;2%)
 

FOCAL CELLULAR CHANGE	 2[»%) 1 :2X)
 

*PTIE DUCT (10) (50) (H8)
 INFI ANIMATION, CHRONIC FOCAL 1[2%)
 

HYPEEPLASIAj, FOCAL 1-12J1_ ~ -.^^^.^ _vw».
 

# NUMBER OF ANIMALS WITH TISSUE EXAMINED MICEOSCOPICAILY
 

* NUMBE" OF ANIMALS NSCRCPSIED
 

66
 
TABLE C1. MALE RATS: NONNEOPLASTIC LESIONS (CONTINUED) 

—«--•=-=> • -~— — —— TM-=~-t •-« •• l-=~==-*-. II- .1 •—_• ._.»»3^D 

MATCHED LOW DOSE 

CONTROL 

iPANCREA S ;10) [HI)

 

PERTAHTEP.ITIS 2 (UX )

 

ATROPHY, NOS 

*PANCR5ATIC ACINUS (10) (i»7)

 

ATROPHY , NOS 3 (6%)

 

ATPOPHY, FOCAL 1 '2X)

 

ISTONAC H (10) (49)

 

CALCIFICATION, METASTATIC 2 (t»X) 

#GASTRIC HOCOSA (10) (i«9)

 

ULCER, NOS 1 (2X)

 

EROSION 2 tW)

 

NECROSIS, FOCAL 1 ;io<) 

CALCIFICATION, METASTATIC 1 ;2%)

 

tGASTRIC SOBMUCOSA (10) (U9)

 

EDEMA , NOS 

ICECUM (7) (UO) 

INFLAMMATION, ACUTE NF.CROTIZING 

UBINAR Y SYSTEM 

*KIDflEY ;10) ;i»9) 

THROHBOSIS, NOS 

INFLAMMATION, CHRONIC 5 (50*) 32 J65%) 

CALCIFICATION, HETASTATIC 1 12%) 

HYPEBPLASIA , FOCAL 2 ;ux) 

METAPLASIA, NOS 1 :2») 

HNDOCRINE SYSTEM 

fPITOITARY 19) ;i»3) 

CYST, NOS 3 (7X) 

MULTIPLE CYSTS 1 ;n*) 

CONGESTION, NOS 2 :5X) 

HEMORRHAG E 5 ;12X) 

DEGENERATION, CYSTIC 1 12%) 

HYPEBPLASIA, FOCAL 3 ;7X) 

AJIGISCT.A§}? _ . _ . 1 J11J1 II • 

* NOBBEB OF ANIHALS WITH TISSOE EXA HI MED MICROSCOPICALLY
 

* NUMBER OF ANIHALS NECROPSIBD
 

HIGH DOSE 

;U6) 

2 («*) i ;2«) 

(U6 ) 

(1*3) 

1 (2X) 

(43) 

7 ;16X) 

(«3) 

1 (2%) 

(24) 

1 ("*) 

147) 

1 (2X) 

3U J72X) 

1 ;2X) 

I37) 

1 *3X) 

1 I3X) 

67
 
TABLE C1. MALE RATS: NONNEOPLASTIC LESIONS (CONTINUED) 

HIGH DOSE
 

(1*5)
 

2 («%)
 

2 :«%)
 

(U5)
 

1 (2%)
 

1 [2%)
 

1 12%)
 

4 ;9%)
 

(1*5)
 

1 (2%)
 

(1*5)
 

8 ;18%)
 

U [31%)
 

(<*5)
 

(33)
 

7 (21%)
 

1 '3%)
 

1* ;12%)
 

(U8)
 

1 (2%)
 

C*6)
 

1 12%)
 

(«6)
 

2 («%)
 

•ADRENAL
 

HEMORRHAGE
 

DEGENERATION, CYSTIC
 

CALCIFICATION, METASTATIC
 

CY^OLOGIC DEGENERATION
 

fADRENAL CORTEX
 

HEMORRHAGE
 

DEGENERATION, NOS
 

DEGENERATION, CYSTIC
 

METAMORPHOSIS FATTY
 

HYPEPPLASIA, FOCAL
 

•ADRENAL	 MFDULIA
 

HYPERPLASIA, FOCAL
 

*THYROTC
 

CYSTIC FOLLICLES
 

ATROPHY, SOS
 

HYPERPLASIA, C-CELL
 

HYPEBPLASIA, FOLLICULAR-CELL
 

•THYPOIC	 FOLLICLE
 

ATROPHY, NOS
 

•PARATHYROID
 

HYPERPLASIA, NOS
 

HYPERPLASIA, SECONDARY
 

HYPERPLASIA, DIFFUSE
 

REPRODUCTIVE SYSTEM
 

*HARBARY GLAND
 

NECROSIS, FAT
 

•PROSTATE
 

DILATATION, NOS
 

OBSTRUCTION, NOS
 

INFLAMMATION ACUTE AND CHRONIC
 

INFLAMMATION, CHRONIC FOCAL
 

ITESTIS
 

PERIARTF.PITIS
 

PERIYHS.CUL.ITIS
 

MATCHED
 

CONTROL
 

(9)
 

(9)
 

(5)
 

(10)
 

1 ;io%)
 

(10)
 

(5)
 

;ioj
 

(10)
 

(10)
 

LOW DOSE
 

(48)
 

5 (10%)
 

5 J10X)
 

1 ;2X>
 

i ;2%>
 

(U8)
 

2 (M)
 

1 ;2X)
 

3 (6%)
 

H [8%)
 

(US)
 

(i»5)
 

6 (13%)
 

1 12%)
 

18 ;uo%)
 

15	 [33%)
 

(t5>
 

1 (2%)
 

(26)
 

2 (8%)
 

2 (8%)
 

ISO)
 

(i»6)
 

1 (2%)
 

1 (2%)
 

1 (2%)
 

C»9)
 

1 M%1
 

I NOHBER Of ANIMALS BTTH TISSUE EXAMINED MICROSCOPICALLY
 

'* HOHBER OP AHIHALS NBCROPSIED
 

68
 
TABLE C1. MALE RATS: NONNEOPLASTIC LESIONS (CONTINUED) 

HIGH DOSE 

20 (H3%) 

;<»7)

1 (2%) 

(U7) 

1 (2t) 

;«8) 

1 (2X) 

;us) 

U (8%) 

i ;2%) 

•U 8 ) 

5 (10%) 

2 

1 

2 

DEGENERATION , NOS 

ATROPHY , NO S 

ATFOPHY, FOCAL 

NEBVOU S SYSTE M 

IBSAIN 

HYDROCEFHALUS, NCS 

#OL?ACTOPY BULB 

GLTOStS 

SPECIAL SENS? OPGAN S 

'EYE/CONJUNCTIV A 

INFLAMMATION , NCS 

IDSCDLOSKFtE^AL SY^TE?! 

*?EHUH 

CSTECPCEOSIS 

FTBPOT1S 03TEODYSTH<">PHY 

BODY CAVITIES 

*MESENTEBY 

PE? TA"TFPITIS 

ALT OTHEB SYSTEMS 

NON E 

SPECIAL MOEPHOLOGY SUMMAR Y 

NO LESION PEPOHTE D 

AtJTO/NECROPSY/HISTO PERF 

&UTOLYSIS/NO NFCPOPSY 

MATCHED LOW DOSE 

CONTROL 

5 (10X) 

1 (10%) 15 (?1%) 1 :2X) 

•JO) :so) 

1 (2%) 

(10) (50) 

;10) :so) 

;m) ISO) 

2 ;i»%) 

;10) ;50)

1

 (2«) 

1 

1 

* NUMBE5 OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NOMEEP OF ANIMALS NECROPSIED
 

69 
TABLE C2.

 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS IN 

FEMALE RATS FED TETRACHLORVINPHOS IN THE DIET 

HIGH DOSE
 

50
 

50
 

50
 

(U9)
 

;48)
 

1 (2%)
 

1 ;2%>
 

;50)
 

1 (2%)
 

150)
 

38 (76%)
 

2 :«%)
 

(50)
 

1 !2*L
 

JNTMALS INITIALLY IN STUDY
 

ANIMALS NFCBOPSIED
 

ANIMALS EXAMINED HISTOF* THOLOGirALLY
 

INTEGUMENTARY SYSTEM
 

NON5
 

RESPIRATORY SYSTEM
 

*LUNG
 

BPOVCHOFNEUMONIA NECRCTIZING
 

INFLAMMATION, FOCA1 GRANULCMATOU
 

HEMATOPOI5TTC SYSTEM
 

fSPLEEN
 

INFARCT, FOCAL
 

HEMOSIDEPOSIS
 

CIPCIILATORY SYSTEM
 

tMYOCARDIUM
 

FIBFOSI?, FOCAL
 

DIGESTIVE SYSTEM
 

*LIVET)
 

HEMORRHAGE
 

INFLAMMATION, GRANOLCMATOOS
 

DEGENERATION, CYSTIC
 

METAMOEPHOSIS FATTY
 

FOCAL CELLULAR CHANGE
 

ANGIECTASIS
 

*BTLE DOCT
 

INFLAMMATION, CH50NIC FOCAL
 

H|PEJPL.A?IA.t FQCAL
 

MATCHED
 

CONTROL
 

10
 

9
 

5
 

(<?)
 

:s)
 

1 (13«)
 

:9>
 

(8)
 

1 :i3%)
 

3 I38H)
 

(9)
 

LOW DOSE
 

50
 

50
 

50
 

(50)
 

1 (2%)
 

1 ;2%)
 

;u9)
 

;50>
 

;a9)
 

1 (2X)
 

10 (20%)
 

1 I2X)
 

2 ;u«)
 

(50)


2 ;<»*)
 

t NOMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

+ NOMBEP OP ANIMAIS NECRCFSIED
 

70
 
TABLE C2. FEMALE RATS: NONNEOPLASTIC LESIONS (CONTINUED) 

MATCHED LOW DOSE HIGH DOSE 

CONTROL 

«PANCPEAS ;9) ;i»8) ;«9) 

HYPFBPLASTIC MODULE 1 (2X) 

*ESOPHAGOS (6) (9)

 

HEGAESOPHAGOS 1 (17*)

 

t?TO(UCH (9) (HB) C*6) 

ULCER , ACUT E 1 (2X) 1 (2X) 

URINAR Y SYSTEM 

#KTDNEY ;9) ;so) ;50) 

m?LAMH»TION , CHRONI C 6 (12%) 11 (22X)

1ETAPLASIA, NOS 1 ;2X) 1 ;2«) 

FNDOCFT1E SYSTE M 

»PTTUT' T 'A?Y ;9) •kut) :n5> 

CYST, NOS 1 (2%) 

CONGESTION , NOS 2 ;s*) 2 ;i»«) 

HE»10B D HAGS 1 ;2%) 

HYFERPL " SI«, NOS 2 ;s«) 

HYPERPHSIA, FOC»L 1 ;2«) 1 ;2X) 

#ADPFN».L (5) (U9) (50) 

HEM"BRH!lG£ 5 (10X) 5 (10X) 

DEGENERATION, CYSTIC 2 ;i»X) 5 ;io%) 

IACPENA L COBTF.X I?) (l»9) (50) 

NODUIE 1 (2%) 

DEGENEH>TION, CYSTIC 10 :2ox) 2 (H%) 

HETAMOFFHOST S FATT Y 1 ;a«) 

HTPEKPL'SIA, FOCAL n ;s%) 2 ;u%) 

tTHYPOID (9) (50) (H6) 

CYSTIC FOLLICLES 1 (2X) 

ATROPHY , NOS 1 ;2%) 

HYPFFPL»SIA , C-CEIL •7 ;n*%) 16 J35S) 

HYPEFPL»SIA , FOILTCDLAR-CELL 1 ;11%) 12 :2UX) 12 t26X) 

BEPHODUCTIV ? SYSTEM 

*P!A!1MRHY GLAN D ;9) ;so) ;50) 

DEGFNEPATION , CYSTIC 1 (2X) -„ HTP?IPl»£IlU_JiOS__ „ ..l^JUJX—__ 8 ;16*1 « :ss) 

* NUMBER OF JNIHSLS WITH TISSUE EXM1IHED MICPOSCOPICRLiY
 

* NOMBF? OF ANIMAIS NECFOPSIF.E
 

71 
TABLE C2. FEMALE RATS: NONNEOPLASTIC LESIONS (CONTINUED) 

MATCHED LOW DOSE HIGH DOSE 

CONTROL 

•OVA3Y (8) (49) (48) 

FOLLTC'JIS.S CYST, NCS 1 (2%)

 

M'PVOOS SYSTE M 

NCN E 

SFFCT A L SENS* ORGAN S 

NONE 

HUSCOIOSKFLETAL SYSTEM 

NONE 

ECD Y CAVITIE S 

NOV F 

B.LL C^HEB SYSTEM S 

NON E 

SPECIAL MOEPHOLOG Y SOMHAF Y 

NO LESIO N FEFOPTED 1 4 3 

AOTOLYSIS/NO NECROPSY 1 

# NUMBER OF ANIMALS WITH TISSUE EXAMINED HICPOSCOPICALLY
 

* NtJMEHS OF ANIMALS NECSCPSIEC
 

72
 
APPENDIX D
 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS
 

IN MICE FED TETRACHLORVINPHOS IN THE DIET
 

73
 

TABLE D1.

 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS IN MALE MICE 

FED TETRACHLORVINPHOS IN THE DIET 

_. .._^TM--J —„._ *._ .—, ... ,TM_ _-^=,»^_ . —..„.. —«—»—.... ».«.._._. 

MATCHED LOW DOSE 

CONTROL 

• NIHSI. S TNITtALI Y T N STUD Y 10 50 

>^!TM?L C . N^CPQPSTE D 9 50 

fNIM^L S IXAMTNE D H T STOP^THCLORTCHLL Y 9 SO 

TN'TnUM^NlUP Y SYSTE M 

NON F 

E V SPID«TO? Y SiSTFM 

• tTlNG/BPCNCHU? : (?) [UQ) 

rNFI'lMA'TION , ^F D O N T r 

*LUM G (8) (U9 ) 

ATHLECT'.SI S 

TNF I S1M1. T IONr "OS 1 :2%> 

TNF1R1MATIO*!, FOCM 

INFt AMM'.TinN , P"CAt GPANnLOMRTO U 1 ;2%) 

HYPEE^L f SIA, MVE^IH H ^PITHELIt tH 1 ;13*) 1 ;2«) 

H"3*!STOPOI5TTC SYSTB H 

HSFLKE N 18) ;«9) 

TNFL>.!1P!ITICS , CHRONI C 2 (U% ) 

HYPEBPLASIP , LYflPHOID 1 ;2«) 

»HESEN"'I3I ^ L. NODE (3) C*3) 

TN^L^HIATIO N , MOS 

NBfpn^If , FOCAL 

TTRCTn,».T05Y SYSTEM 

*"IYOCA c DTn n ;8) ;«9) 

TNPT AMM? T I O N, IW'EPSTT'IIAL 1 (2%) 

B T GFSTTV E SYSTE M 

*LIV5« ( 9) (50) 

TNI ?LA!1M^TIONJ I_GFANUICMA1rOUS „._.._. 50_J1fi2JJL 

* NfJflBEP OF ANTMBL S WTTH TISSUE EXAMINE D MICROSCOPICALLY 

* IIDMBE F 0" ANIMA1 S NECPOPSTE C 

HIGH DOSE 

50 

50 

50 

(50) 

1 (2% ) 

(50) 

1 (2%) 

1 ;2%) 

I-50) 1

 (2t) 

(38) 

1 (3% ) 

1 :3%) 

;5o> 

(50) 

U9_J98%1 

75 
TABLE D1. MALE MICE: NONNEOPLASTIC LESIONS (CONTINUED) 

MATCHED LOW DOSE HIGH DOSE 

CONTROL 

IN Ft* HI! mo H, PCCU GRANUICMATO U 1 (2%) 

FOCAL cmtJLAF CHANGE 1 J2») 

*PILE DOCT (9) (50) (50)

 

Dlt.nHTION, NOS 1 ;2%) 

*PSNCPEATIC DOCT (8) (U8) (50)

 

CTLJT^TION, NOS 1 <2X) 

flSTNAH Y SYSTE M 

fKTDNE Y :9> ;50> ;50) 

INFLAMMATION , FOCAL GBANULOMATO P 1 (2X) 

HYP?*PLASIA , TfJPOL» P CEIL 1 :2X) 

ME^STLASIA, OS5EOOS 1 :2%) 

HSOOrFIN E SYSTEM 

•'HYB^TO :<*} ;«7) :t7> 

HYPIFPI.'SIA, POILICOHH-CELL 2 («*) 1. (2%) 

"EPpriDarTlVE SYSTEM 

*CrAG'II ^TIMG GIAH D ; 9> :soj ;50) 

"ETENTIC N FiniD 1 (2t) 

*Vf.S DTP5HEHS (9) (50) (50) 

DltJ.T^TI^N, NOS 1 ;2«) 

NSPVOUS SYSTE.1 

THOPOTD PIEXOS : 9> ;50) ;50)

 «>I

''!>.FMSIA, SQm«OnS 1 (2*)

 

5FECIA L SENSE OSGSN S 

NONE 

ItJSCULOSKELETA L SYSTEM 

*F»Hm? (9) (50) (50) 

QRiVDLOMit HQS _ „ J. _. ^U. _t«.»^.K JMK.k -, _ ^TM^1

 :^«> 

* VHMBE S OF RNISAtS WITH TISSUE EXAMINE D PITCROSCOPICMIY 

» NUM95 P OF fNTHU S NEC'CPSIED 

76 
1 

TABLE 01. MALE MICE: NONNEOPLASTIC LESIONS (CONTINUED) 

•— • •• ' — • < — MATCHED LOW DOSE HIGH DOSE 

CONTROL 

ECDY C1UITIES 

NON E 

A LL OTHEE SYSIEBS 

NONE 

SPECIAL BOBPHOLOGY SOBBftKY 

NO LESION BEFOPTED 5

 

iOTO/NECBOPSY/HISTO PERF 1

 

*nTOLYSIS/lIO NECROPSY 1 

* NOHBF.P OF ANIMALS WITH TISSUE EXARISED HICBOSCOPICALLY
 * NUMBER OF ANIHAIS HECSOPSIED
 

77
 
TABLE 02.

 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS IN 

FEMALE MICE FED TETRACHLORVINPHOS IN THE DIET 

SNIMALS INITIALLY IN STUDY
 

ANIMALS NECFOPSIED
 

ANIMALS EXAMINED HI STOPATHOLOGICALLY
 

INTEGUMENTARY SYSTEM
 

NONE
 

RESPIRATORY SYSTEM
 

fLONG
 

INFLAMMATION, FOCAL
 

HEMATOPOTETIC SYSTEM
 

•SPLEEN
 

ABSCESS, NOS
 

INFLAMMATION, CHRONIC
 

HYPEHPLASIA, LYHPHOID
 

*LY«PH NODE
 

INFLAMMATION, CHRONIC
 

CIRCULATOR! SYSTEM
 

tHYOCARDIDM
 

INFLAMMATION, INTERSTITIAL
 

DIGESTIVE SYSTEM
 

ILITER
 

INFLAMMATION, GRANULCMATOUS
 

ANGIECTASIS
 

*BILE DOCT
 

DJL.ATATI01U HOS
 

MATCHED
 

CONTROL
 

aio
 

9
 

9
 

(9)
 

19)
 

(9)
 

I9)
 

:9)
 

(9)
 

• 1 •«
 

LOW DOSE
 

50
 

49
 

49
 

(«9)
 

1 (2%)
 

;i»6)
 

2 t«*X)
 

5 (11X)
 

(39)
 

1 (3«)
 

;«8)
 

:n9>
 

48 (98%)
 

1 [2%)
 

(49)
 

1.I2S1
 

HIGH DOSE
 

650
 

47
 

47
 

(47)
 

J47)
 

1 (2X)
 

3 ;6X)
 

(42)
 

147)
 

1 (2X)
 

!47)
 

47 (100*)
 

(47)
 

1 '?«i
 

» NUMBER OP ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 * NUMBER OF ANIMALS NECFOPSIED
 

» 10 ANIMALS HERE INITIALLY IN STUDY BUT ONE HAS HBLETED WHEN POUND TO BE A MALE
 

ANIMAL IN * FINALE GROUP.
 

6 50 ANIMALS HERE INITIALLY IN STUDY BUT ONE HAS BELETED HH El POUND TO BE A MALE
 •ANIMAL IN A FEMALE GROUP.
 

78 
TABLE 02. FEMALE MICE: NONNEOPLASTIC LESIONS (CONTINUED) 

#PANCPEAS 

NECROSIS, FAT 

tPANCPEATIC DOCT 

DILATATION , NOS

 

IPANCPEATIC ACINUS 

ATROPHY , NOS 

UBINAP Y SYSTEM 

HKIDNE Y 

HYDRONEPHKOSIS 

INFLAMMATION , CHRONIC 

#KTDNFY/CORTEX 

ATROPHY , NO S 

ENDOCRIN E SYSTEM 

((PITUITAR Y 

HYPEPPLASI A , NOS 

ANGIECTASIS 

#THYFOT D 

HYPERP1ASIA , C-CELL 

HYPERPLASIA , FOl LICOLAS-CELL 

REPRODUCTIV E SYSTEM 

*OTEROS 

HYOROMETS A 

INFLAMMATION , SUPPORATIV E 

#OTEPUS/ENDO«ETPIU M 

HYPFRPLASIA , FOCAL 

HYPEPPLASIA , CYSTIC

 

IOVAP Y 

CISTENTION 

FOLLICOLAR CYST, NOS 

INFLAMMATION ^ NOS 

t NTJMBER OF ANIMAL S WIT H TISSUE

* NUMBE R OF ANIMAL S NECBOPSIF.D 

MATCHED 

CONTROL 

(9) 

(9) 

(9) 

19) 

(9) 

; 5> 

(9) 

: s> 

(8) 

3 ;38%) 

(8) 

1 ;13*) 

LOW DOSE 

(45) 

(U5) 

3 (7X) 

(«»5) 

3 (7%) 

;u9> 

(U9) 

;us) 

1 (2% ) 

2 ;«%) 

(t6) 

1 (2X ) 

2 ;<»%) 

;i»7) 

1

 ;2%) 

(U7) 

2 ;«*) 

(1*7) 

1_:2«L_ 

 EXAMINE D MICROSCOPICALL Y 

HIGH DOSE 

(HI) 

1 (2X) 

(HI) 

(U7 ) 

;U6) 

5 (11%) 

1 ;2%) 

(«6) 

1 (2K ) 

;39) 

(U1 ) 

:39) 

1 (3% ) 

(39) 

1 (3% ) 

(4U ) 

1 (2%) 

1 I2*) 

.TM-.2_J16?J 

79
 
TABLE D2. FEMALE MICE: NONNEOPLASTIC LESIONS (CONTINUED) 

IHPLAH NATION, SOPPURATIVE
 

INFLAMMATION, CHRONIC
 

ATROPHY, NOS
 

NERVOOS SYSTEtt
 

NONE
 

SPECTRL SENSE ORGANS
 

NONE
 

MUSCOIDSKELETAL SYSTEM
 

NONE
 

BODY CAVITIES
 

NONE
 

ML CTHER SYSTEMS
 

NONE
 

SPECI?! MORPHOLOGY SUMMARY
 

NO LESION REPORTED
 

AOTO/NECROPSY/HISTO PERF
 

AUTOLYSTS/NO NECROPSY
 

# NUHBEB OF ANIMALS HITH TISSUE	 EXAMINED


* NUMBER OF ANIMALS NEC90PSIED
 

MATCHED LOW DOSE HIGH DOSE
 

CONTROL
 

1 (13*)	 2 (5*)
 

2 ;5«)
 

1 ;2*>
 

U
 

1
 

1 2
 

 MICROSCOPICAIIY
 

80
 
APPENDIX E
 

ANALYSES OF THE INCIDENCE OF PRIMARY TUMORS IN RATS
 

FED TETRACHLORVINPHOS IN THE DIET
 

81
 

__ __ 

__ 

Table El.


Topography: Morphology
 

Thyroid: Follicular-cell
 

Carcinoma
 

P	 Values0 »d
 

Relative Risk (Matched Control)f
 

Lower Limit
 

Upper Limit
 

Relative Risk (Pooled Control)f
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Thyroid: Follicular-cell
 

Adenoma or Carcinoma
 

P	 Valuesc»d
 

Relative Risk (Matched Control)f
 

Lower Limit
 

Upper Limit
 

Relative Risk (Pooled Control)f
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

 Analyses of the Incidence of Primary Tumors in Male Rats
 

Fed Tetrachlorvinphos in the Diet3
 

Matched Pooled Low High
 

Control Control Dose Dose
 

0/10 (0) 1/46 (2) 3/45 (7) 2/45 (4)
 

N.S.	 N.S. N.S. N.S.
 

Infinite Infinite
 

0.149 0.072
 

Infinite Infinite
 

3.067 2.044
 

0.260 0.111
 

155.684	 115.984
 

111 111
 

0/10 (0) 4/46 (9) 4/45 (9) 2/45 (4)
 

N.S.	 N.S. N.S. N.S.
 

Infinite Infinite
 

0.229 0.072
 

Infinite Infinite
 

1.022 0.511
 

0.202 0.048
 

5.160	 3.362
 

111 111
 —
 
Table El.


(continued)
 

Topography: Morphology
 

Thyroid: C-cell Adenomab
 

P Values0 >d
 

Relative Risk (Matched Control)*
 

Lower Limit
 

Upper Limit
 

Relative Risk (Pooled Control)f
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Thyroid: C-cell
 

Adenoma or Carcinoma'3
 

P Values0 »d
 

Relative Risk (Matched Control)f
 

Lower Limit
 

Upper Limit
 

Relative Risk (Pooled Control)f
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

 Analyses of the Incidence of Primary Tumors in Male Rats
 

Fed Tetrachlorvinphos in the Dieta
 

Matched Pooled Low High 

Control Control Dose Dose 

1/10 (10) 2/46 (4) 2/45 (4) 3/45 (7) 

N.S. N.S. N.S. N.S. 

0.444 0.667 

0.027 0.065 

25.233 34.664 

1.022 1.533 

0.077 0.184 

13.502 17.729 

Ill ._ 

111 111 

1/10 (10) 2/46 (4) 2/45 (4) 4/45 (9)
 

N.S. N.S. N.S. N.S.
 

0.444 0.889
 

0.027 0.108
 

25.233 43.482
 

1.022 2.044
 

0.077 0.309
 

13.502 21.921
 

Ill 111
 —
 111 
__ 

__ 

__ 

Table El. Analyses of the Incidence of Primary Tumors in Male Rats
 

Fed Tetrachlorvinphos in the Diet3
 

(continued)
 

Topography: Morphology
 

Pituitary: Chromophobe
 

Adenoma
 

P Values0 »d
 

Relative Risk (Matched Control)f
 

Lower Limit
 

Upper Limit
 

Relative Risk (Pooled Control)f
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Adrenal: Cortical
 

Adenoma
 

P Valuesc»d
 

Relative Risk (Matched Control)

f
 

Lower Limit
 

Upper Limit
 

Relative Risk (Pooled Control)f
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Matched
 

Control
 

4/9 (44)
 

P < O.OOl(N)
 

74
 

0/9 (0)
 

N.S.
 

—
 

Pooled
 

Control
 

6/46 (13)
 

P = 0.033(N)
 

2/52 (4)
 

N.S.
 

Low
 

Dose
 

5/43 (12)
 

P = 0.037*(N)
 

0.262
 

0.084
 

1.139
 

0.891
 

0.231
 

3.255
 

107
 

3/48 (6)
 

N.S.
 

Infinite
 

0.127
 

Infinite
 

1.625
 

0.195
 

18.563
 

111
 

High
 

Dose
 

0/37 (0)
 

P = 0.023**(N)
 

P < 0.001*(N)
 

0.000
 

0.000
 

0.250
 

0.000
 

0.000
 

0.769
 

1/45 (2)
 

N.S.
 

Infinite
 

0.012
 

Infinite
 

0.578
 

0.010
 

10.753
 

110
 
Table El.


(continued)
 

Topography: Morphology
 

Spleen: Hemangioma"3
 

P Values0 >d
 

Departure from Linear Trend6
 

Relative Risk (Matched Control)f
 

Lower Limit
 

Upper Limit
 

Relative Risk (Pooled Control)f
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

 Analyses of the Incidence of Primary Tumors in Male Rats
 

Fed Tetrachlorvinphos in the Diet3
 

Matched Pooled Low High 

Control Control Dose Dose 

0/10 (0) 0/52 (0) 4/48 (8) 0/47 (0) 

N.S. N.S. P = 0.049** N.S. 

P = 0.004 

Infinite — 0.215 — Infinite — 

Infinite — 1.004 

Infinite — 

— 

111 — — — 
Table El. Analyses of the Incidence of Primary Tumors in Male Rats
 

Fed Tetrachlorvinphos in the Diet3
 

(continued)
 

a

Treated groups received time-weighted average doses of 4,250 or 8,500 ppm.
 

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

c

Beneath the incidence of tumors in a control group is the probability level for the Cochran-


Armitage test when P < 0.05; otherwise, not significant (N.S.) is indicated. Beneath the incidence of tumors in a treated group is the probability level for the Fisher exact test for the
 

comparison of that treated group with the matched-control group (*) or with the pooled-control
 

group (**) when P < 0.05 for either control group; otherwise, not significant (N.S.) is indicated.
 

^A negative trend (N) indicates a lower incidence in a treated group than in a control group.
 

e

The probability level for departure from linear trend is given when P < 0.05 for any comparison.
 

^The 95% confidence interval of the relative risk between each treated group and the specified
 

control group.
 
__ 

__ 

__ 

_ _ 

Table E2.


Topography: Morphology
 

Thyroid: Follicular-cell
 

Adenoma
 

P Values0 >d
 

Relative Risk (Matched Control)f
 

Lower Limit
 

Upper Limit
 

Relative Risk (Pooled Control)f
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Thyroid: C-cell Adenoma'3
 

P Values0 »d
 

Relative Risk (Matched Control)f
 

Lower Limit
 

Upper Limit
 

Relative Risk (Pooled Control)f
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

 Analyses of the Incidence of Primary Tumors in Female Rats
 

Fed Tetrachlorvinphos in the Diet3
 

Matched Pooled Low High
 

Control Control Dose Dose
 

0/9 (0) 0/46 (0) 0/50 (0) 1/46 (2)
 

N.S. N.S. N.S. N.S.
 

Infinite
 

0.011
 —
 Infinite
 —
 

Infinite
 

0.054
 —
 Infinite
 —
 

98
 —
 

1/9 (11) 1/46 (2) 2/50 (4) 7/46 (15)
 

N.S. P = 0.013 N.S. P = 0.027**
 

0.360 1.370
 

0.023 0.224
 

20.996 60.637
 

1.840 7.000
 

0.100 0.954
 

107.069 307.988
 

Ill 111
 88
 —
 
__ 

__ 

Table E2. Analyses of the Incidence of Primary Tumors in Female Rats
 

(continued)
 

Topography: Morphology
 

Liver: Neoplastic Nodule'3
 

P Values0 »d
 

Relative Risk (Matched Control)^
 

Lower Limit
 

Upper Limit
 

Relative Risk (Pooled Control)f
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Pituitary: Chromophobe
 

Adenoma"
 

P Values0 »d
 

Departure from Linear Trend6
 

Relative Risk (Matched Control)^
 

Lower Limit
 

Upper Limit
 

Relative Risk (Pooled Control)f
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Fed Tetrachlorvinphos in the Diet3
 

Matched Pooled Low 

Control Control Dose 

0/8 (0) 1/53 (2) 2/49 (4) 

N.S. N.S. N.S. 

Infinite 

0.055 

Infinite 

2.163 

0.117 

124.171 

__ __ 

111 

0/9 (0) 9/46 (20) 1/44 (2)
 

P = 0.021 N.S. P = 0.010**
 

P = 0.012
 

Infinite
 

0.012
 

Infinite
 

0.116
 

0.003
 

0.785
 

111
 —
 —
 

High
 

Dose
 

0/49 (0)
 

N.S.
 

—
 

—
 

0.000
 

0.000
 

20.103
 

7/45 (16)
 

(N) N.S.
 

Infinite
 

0.441
 

Infinite
 

0.795
 

0.274
 

2.192
 

107 
Table E2.


(continued)
 

Topography: Morphology
 

Adrenal: Cortical Adenoma
 

P Values0'd
 

Relative Risk (Matched Control)f
 

Lower Limit
 

Upper Limit
 

Relative Risk (Pooled Control)f
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Mammary Gland: Fibroadenoma
 

P Values0 »d
 

Relative Risk (Matched Control)f
 

Lower Limit
 

Upper Limit
 

Relative Risk (Pooled Control)f
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

 Analyses of the Incidence of Primary Tumors in Female
 

Fed Tetrachlorvinphos in the Diet3
 

Matched Pooled Low 

Control Control Dose 

0/9 (0) 0/50 (0) 2/49 (4) 

N.S. P = 0.017 N.S. 

Infinite 

0.061 

Infinite 

Infinite 

0.301 

Infinite __ __ 

111 

3/9 (33) 8/54 (15) 4/50 (8) 

P = 0.044(N) N.S. N.S. 

0.240 

0.056 

1.467 

0.540 

0.126 

1.888 

82 111 —— 

Rats
 

High
 

Dose
 

5/50 (10)
 

P = 0.022**
 

Infinite
 

0.257
 

Infinite
 

Infinite
 

1.258
 

Infinite
 

107
 

3/50 (6)
 

P = 0.040*(N)
 

0.180
 

0.032
 

1.212
 

0.405
 

0.073
 

1.585
 

90
 
Table E2. Analyses of the Incidence of Primary Tumors in Female Rats
 

Fed Tetrachlorvinphos in the Diet3
 

(continued)
 

a

Treated groups received time-weighted average doses of 4,250 or 8,500 ppm.
 

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

c

Beneath the incidence of tumors in a control group is the probability level for the Cochran-


Armitage test when P < 0.05; otherwise, not significant (N.S.) is indicated. Beneath the incidence of tumors in a treated group is the probability level for the Fisher exact test for the
 

comparison of that treated group with the matched-control group (*) or with the pooled-control
 

group (**) when P < 0.05 for either control group; otherwise, not significant (N.S.) is indicated.
 

^A negative trend (N) indicates a lower incidence in a treated group than in a control group.
 

e

The probability level for departure from linear trend is given when P < 0.05 for any comparison.
 

APPENDIX F
 

ANALYSES OF THE INCIDENCE OF PRIMARY TUMORS IN MICE
 

FED TETRACHLORVINPHOS IN THE DIET
 

93
 

__ __ 

__ 

Table Fl. Analyses of the Incidence of Primary Tumors in Male Mice
 

Topography: Morphology
 

Lung: Alveolar/Bronchiolar
 

Adenoma
 

P Values0 >d
 

Relative Risk (Matched Control)f
 

Lower Limit
 

Upper limit
 

Relative Risk (Pooled Control)^
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Lung: Alveolar/Bronchiolar
 

Carcinoma
 

P Values0 »d
 

Departure from Linear Trend6
 

Relative Risk (Matched Control)*
 

Lower Limit
 

Upper Limit
 

Relative Risk (Pooled Control)f
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Fed Tetrachlorvinphos in the Diet3
 

Matched Pooled Low
 

Control Control Dose
 

0/8 (0)	 3/47 (6) 1/49 (2)
 

N.S.	 N.S. N.S.
 

Infinite
 

0.010
 

Infinite
 

0.320
 

0.006
 

3.834
 

93
 

0/8 (0)	 0/47 (0) 3/49 (6)
 

N.S.	 N.S. N.S.
 

P =	 0.014
 

Infinite
 

0.113
 

Infinite
 

Infinite
 

0.413
 

Infinite
 

93
 —	 —
 

High
 

Dose
 

2/50 (4)
 

N.S.
 

Infinite
 

0.054
 

Infinite
 

0.627
 

0.054
 

5.234
 

0/50 (0)
 

N.S.
 

—
 

—
 

—
 

—
 

—
 

—
 

82 
Table Fl.


(continued)
 

Topography: Morphology
 

Lung: Alveolar /Bronchiolar
 

Adenoma or Carcinoma
 

P Valuesc'd
 

Relative Risk (Matched Control)f
 

Lower Limit
 

Upper Limit
 

Relative Risk (Pooled Control)f
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Liver: Neoplastic Nodule'3
 

P Values0 >d
 

Departure from Linear Trend6
 

Relative Risk (Matched Control)f
 

Lower Limit
 

Upper Limit
 

Relative Risk (Pooled Control)f
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

 Analyses of the Incidence of Primary Tumors in Male Mice
 

Fed Tetrachlorvinphos in the Dieta
 

Matched Pooled Low High
 

Control Control Dose Dose
 

0/8	 (0) 3/47 (6) 4/49 (8) 2/50 (4)
 

N.S.	 N.S. N.S. N.S.
 

Infinite Infinite
 

0.175 0.054
 

Infinite Infinite
 

1.279 0.627
 

0.229 0.054
 

8.319	 5.234
 

—.	 93
 82
 ——
 

0/9 (0) 3/49 (6)	 11/50 (22) 2/50 (4)
 

N.S.	 N.S. P = 0.024** N.S.
 

P = 0.002
 

Infinite Infinite
 

0.678 0.060
 

Infinite Infinite
 

3.593 0.653
 

1.024 0.057
 

18.934	 5.471
 

93 93
 —	 —
 
Table Fl. Analyses of the Incidence of Primary Tumors in Male Mice
 

(continued)
 

Topography: Morphology
 

Liver: Hepatocellular
 

Carcinoma
 

P Values0 »d
 

Departure from Linear Trend6
 

Relative Risk (Matched Control)f
 

Lower Limit
 

Upper Limit
 

Relative Risk (Pooled Control)^
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Fed Tetrachlorvinphos in the Dieta
 

Matched Pooled Low
 

Control Control Dose
 

0/9 (0) 5/49 (10) 36/50 (72)
 

P < 0.001 P < 0.001	 P < 0.001**
 

P < 0.001*
 

P = 0.003 P = 0.002
 

Infinite
 

2.485
 

Infinite
 

7.056
 

3.176
 

19.491
 

67
 —
 —
 

High
 

Dose
 

40/50 (80)
 

P < 0.001**
 

P < 0.001*
 

Infinite
 

2.795
 

Infinite
 

7.840
 

3.622
 

20.198
 

78
 
Table Fl. Analyses of the Incidence of Primary Tumors in Male Mice
 

Fed Tetrachlorvinphos in the Diet3
 

(continued)
 

Matched Pooled Low High
 

Topography: Morphology Control Control Dose Dose
 

Liver: Neoplastic Nodule or
 

Hepatocellular Carcinoma 0/9 (0) 8/49 (16) 47/50 (94) 42/50 (84)
 

P Values0 »d P = 0.001 P < 0.001	 P < 0.001** P < 0.001**
 

P < 0.001* P < 0.001*
 

Departure from Linear Trend6 P < 0.001 P < 0.001
 

Relative Risk (Matched Control)f Infinite Infinite
 

Lower Limit 3.425 2.956
 

Upper Limit Infinite Infinite
 

Relative Risk (Pooled Control)f 5.758 5.145
 

Lower Limit 3.429 2.866
 

Upper Limit 8.321 9.455
 

Weeks to First Observed Tumor	 67 78
 — —
 a

Treated groups received doses of 8,000 or 16,000 ppm.
 

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

c

Beneath the incidence of tumors in a control group is the probability level for the Cochran-


Armitage test when P < 0.05; otherwise, not significant (N.S.) is indicated. Beneath the incidence of tumors in a treated group is the probability level for the Fisher exact test for the
 

comparison of that treated group with the matched—control group (*) or with the pooled—control
 

group (**) when P < 0.05 for either control group; otherwise, not significant (N.S.) is indicated.
 
Table Fl. Analyses of the Incidence of Primary Tumors in Male Mice
 

Fed Tetrachlorvinphos in the Dieta
 

(continued)
 

"A negative trend (N) indicates a lower incidence in a treated group than in a control group.
 

e

The probability level for departure from linear trend is given when P < 0.05 for any comparison.
 

^The 95% confidence interval of the relative risk between each treated group and the specified
 

control group.
 
__ __ 

__ 

Table F2.


Topography: Morphology
 

Lung: Alveolar /Bronchiolar
 

Adenoma
 

P Values0 >d
 

Relative Risk (Matched Control)f
 

Lower Limit
 

Upper limit
 

Relative Risk (Pooled Control)f
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Lung: Alveolar /Bronchiolar
 

Carcinoma
 

P Values0 »d
 

Relative Risk (Matched Control)f
 

Lower Limit
 

Upper Limit
 

Relative Risk (Pooled Control)f
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

 Analyses of the Incidence of Primary Tumors in Female Mice
 

Fed Tetrachlorvinphos in the Dieta
 

Matched Pooled Low High
 

Control Control Dose Dose
 

0/9 (0) 1/48 (2) 4/49 (8) 5/47 (11)
 

N.S. N.S. N.S. N.S.
 

Infinite Infinite
 

0.192 0.274
 

Infinite Infinite
 

3.918 5.106
 

0.405 0.602
 

188.830 238.482
 

92 84
 

0/9 (0) 1/48 (2) 1/49 (2) 0/47 (0)
 

N.S. N.S. N.S. N.S.
 

Infinite
 

0.011
 

Infinite
 —


—
 

0.980 0.000
 

0.013 0.000
 

75.635 38.589
 

92
 — —
 ——

__ _ 

Table F2. Analyses of the Incidence of Primary Tumors in Female Mice
 

(continued)
 

Topography: Morphology
 

Lung: Alveolar /Bronchiolar
 

Adenoma or Carcinoma
 

P Valuesc>d
 

Relative Risk (Matched Control)f
 

Lower Limit
 

Upper Limit
 

Relative Risk (Pooled Control)^
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Liver: Neoplastic Nodule"
 

P Values0 >d
 

Departure from Linear Trend6
 

Relative Risk (Matched Control)f
 

Lower Limit
 

Upper Limit
 

Relative Risk (Pooled Control)f
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Fed Tetrachlorvinphos in the Diet3
 

Matched Pooled Low
 

Control Control Dose
 

0/9 (0) 2/48 (4) 5/49 (10)
 

N.S. N.S. N.S.
 

Infinite
 

0.262
 

Infinite
 

2.449
 

0.424
 

24.674
 

_


92
 

0/9 (0) 1/48 (2) 14/49 (29)
 

N.S. P = 0.018 P < 0.001**
 

P = 0.047 P = 0.006
 

Infinite
 

0.909
 

Infinite
 

13.714
 

2.238
 

569.159
 

84
 —
 —
 

High
 

Dose
 

5/47 (11)
 

N.S.
 

Infinite
 

0.274
 

Infinite
 

2.553
 

0.444
 

25.945
 

84
 

9/47 (19)
 

P - 0.007**
 

Infinite
 

0.571
 

Infinite
 

9.191
 

1.351
 

391.340
 

90
 
Table F2. Analyses of the Incidence of Primary Tumors in Female Mice
 

Fed Tetrachlorvinphos in the Diet3
 

(continued) 

Matched Pooled Low High 

Topography: Morphology Control Control Dose Dose 

Liver: Hepatocellular
 

Carcinoma 0/9 (0) 2/48 (4) 5/49 (10) 2/47 (4)
 

P Valuesc»d N.S. N.S. N.S. N.S.
 

Relative Risk (Matched Control)f Infinite Infinite
 

Lower Limit 0.262 0.063
 

Upper Limit Infinite Infinite
 

Relative Risk (Pooled Control)f 2.449 1.021
 

Lower Limit 0.424 0.077
 

Upper Limit 24.764 13.550
 

Weeks to First Observed Tumor 92
 —
 —
 93 
Table F2. Analyses of the Incidence of Primary Tumors in Female Mice
 

Fed Tetrachlorvinphos in the Diet3
 

—
 

(continued) 

Topography: Morphology 

Matched 

Control 

Pooled 

Control 

Low 

Dose 

High 

Dose 

Liver: Neoplastic Nodule or 

Hepatocellular Carcinoma 0/9 (0) 3/48 (6) 19/49 (39) 11/47 (23) 

P Values0'd N.S. P = 0.030 P < 0.001** 

P = 0.020* 

P = 0.019** 

Departure from Linear Trend6 P = 0.010 P = 0.002 

Relative Risk (Matched Control)f 

Lower Limit 

Upper Limit 

Infinite 

1.274 

Infinite 

Infinite 

0.722 

Infinite 

Relative Risk (Pooled Control)f 

Lower Limit 

Upper Limit 

6.204 

2.004 

30.490 

3.745 

1.068 

19.601 

Weeks to First Observed Tumor — 84 90 

a

Treated groups received doses of 8,000 or 16,000 ppm.
 

^Number of tumor-bearing animals/number of animals examined at site (percent).
 
Table F2. Analyses of the Incidence of Primary Tumors in Female Mice
 

Fed Tetrachlorvinphos in the Diet3
 

(continued)
 

c

Beneath the incidence of tumors in a control group is the probability level for the Cochran-


Armitage test when P < 0.05; otherwise, not significant (N.S.) is indicated. Beneath the incidence of tumors in a treated group is the probability level for the Fisher exact test for the
 

comparison of that treated group with the matched-control group (*) or with the pooled-control
 

group (**) when P < 0.05 for either control group; otherwise, not significant (N.S.) is indicated.
 

^A negative trend (N) indicates a lower incidence in a treated group than in a control group.
 

e

The probability level for departure from linear trend is given when P < 0.05 for any comparison.
 

^The 95% confidence interval of the relative risk between each treated group and the specified
 

control group.
 
APPENDIX G
 

ANALYSIS OF FORMULATED DIETS FOR
 

CONCENTRATIONS OF TETRACHLORVINPHOS
 

105
 

APPENDIX G
 

Analysis of Formulated Diets for
 

Concentrations of Tetrachlorvinphos
 

A 100-g sample of the diet mixture was shaken with 100 ml hexane
 

at room temperature for 16 hours, then filtered through Celite
 

with hexane washes, and reduced in volume to 10 ml. After
 

appropriate dilutions, the solution was quantitatively analyzed
 

for tetrachlorvinphos by gas-liquid chromatography (electroncapture detector, 5% QF-1 on Chromosorb W column). Recoveries
 

were checked with spiked samples, and external standards were
 

used for calibration.
 

Theoretical 

Concentrations 

in Diet (ppm) 

No. of 

Samples 

S ample 

Analytical 

Mean (ppm) 

Coefficient of 

Variation (%) 

Range (ppm) 

4,000 23 4,015 4.5% 3,591-4,296 

8,000 28 7,993 5.1% 7,060-8,610 

16,000 26 15,760 5.3% 13,500-17,280 

107
 

Review of the Bioassay of Tetrachlorvinphos*for Carcinogenicity
 

by the Data Evaluation/Risk Assessment Subgroup of the
 

Clearinghouse on Environmental Carcinogens
 

November 28, 1977
 

The Clearinghouse on Environmental Carcinogens was
 

established in May, 1976 under the authority of the National
 

Cancer Act of 1971 (P.L. 92-218). The purpose of the Clear­ inghouse is to advise on the National Cancer 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, State
 

health officials, and quasi-public health and research
 

organizations. Members have been selected on the basis of
 

their experience in carcinogenesis or related fields and,
 collectively, provide expertise in organic chemistry, bio­ chemistry, 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 NCI bioassay reports on chemicals
 

studied for carcinogenicity. In this context, below is the
 

edited excerpt from the minutes of the Subgroup's meeting at
 

which Tetrachlorvinphos was reviewed.
 

The primary reviewer noted that Tetrachlorvinphos
 

induced neoplastic changes in the livers of the treated
 

mice. He was uncertain, however, as to the interpretation
 

of the changes in view of the controversial nature of the
 

lesions. He said that if the diagnoses of the liver lesions
 

are accepted as given in the report, the incidence of hepatocellular
 

carcinomas was dose-related. In regard to the finding of an
 

increased incidence of cortical adenomas of the adrenal in
 

treated female rats, the reviewer said that he had difficulty
 

in evaluating this type of lesion. He added that the adenomas
 

were statistically significant when compared to the historical
 

control animals. The reviewer was most skeptical of the
 

significance of the dose-related trend in thyroid C-cell
 

adenomas in treated female rats. He noted that thyroid
 

proliferative lesions were found in almost all of the rats.
 

In commenting on the pathology findings, an NCI staff
 

pathologist said that the mouse liver lesions were reexamined
 

and the diagnoses of hepatocellular carcinomas confirmed.
 In regard to the thyroid lesions, he said that the staff was
 

confident that they were treatment-related.
 

A consultant to Shell Oil Company discussed the views
 

of Shell regarding the Tretrachlorvinphos study. He
 

109
 
said that consultant pathologists to Shell have reviewed the
 

mouse liver lesions and found no increase in the incidence
 

of hepatocellular carcinomas among the treated animals. He
 

also noted that at the same time the Tetrachlorvinphos study
 

was underway, Dieldrin and Malathion were being tested in
 

the same room. He suggested that, through cross-contamination,
 these compounds may have acted as potentiators of toxicity
 

in the Tetrachlorvinphos treated mice, resulting in an
 

increase of hepatocellular carcinomas over and above the
 

baseline incidence. He mentioned other variables that could
 

have affected the findings. In conclusion, he briefly
 

described the ongoing Shell-sponsored study.
 

A motion was made that Tetrachlorvinphos induced
 

hepatocellular carcinomas in mice under the conditions of
 

test. The motion was seconded and approved unanimously.
 

Members present were:
 

Gerald N. Wogan (Chairman), Massachusetts Institute of
 

Technology
 

Lawrence Garfinkel, American Cancer Society
 

Henry C. Pitot, University of Wisconsin Medical Center
 

George Roush, Jr., Monsanto Company
 

Verald K. Rowe, Dow Chemical U.S.A.
 Michael B. Shimkin, University of California at San Diego
 

Louise Strong, University of Texas Health Sciences Center
 

John H. Weisburger, American Health Foundation
 

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.
 

110
 

*U.S. GOVERNMENT PRINTING OFFICE:1978 2611-899/3010 1-3 


DHEW Publication No. (NIH) 78-833