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National Cancer Institute 

CARCINOGENESIS 

Technical Report Series 

No. 97 

BIOASSAY OF 

TITANIUM DIOXIDE 

FOR POSSIBLE CARCINOGENICITY 

CAS No. 13463-67-7 

NCI-CG-TR-97 

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

Public Health Service 

National Institutes of Health 

BIOASSAY OF
 

TITANIUM DIOXIDE
 

FOR POSSIBLE CARCINOGENICITY
 

Carcinogenesis Testing Program
 

Division of Cancer Cause and Prevention
 

National Cancer Institute
 

National Institutes of Health
 

Bethesda, Maryland 20014
 

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

Public Health Service
 

National Institutes of Health
 

DREW Publication No. (NIH) 79-1347
 
ii

 
BIOASSAY OF
 

TITANIUM DIOXIDE
 

FOR POSSIBLE CARCINOGENICITY
 

Carcinogenesis Testing Program
 

Division of Cancer Cause and Prevention
 

National Cancer Institute
 

National Institutes of Health
 

FOREWORD; This report presents the results of the bioassay of
 

titanium dioxide conducted for the Carcinogenesis Testing
 

Program, Division of Cancer Cause and Prevention, National Cancer
 

Institute (NCI), National Institutes of Health, Bethesda,
 

Maryland. This is one of a series of experiments designed to
 

determine whether selected chemicals have the capacity to produce
 

cancer in animals. Negative results, in which the test animals
 

do not have a greater incidence of cancer than control animals,
 

do not necessarily mean that the test chemical is not a
 

carcinogen, inasmuch as the experiments are conducted under a
 

limited set of circumstances. Positive results demonstrate that
 

the test chemical is carcinogenic for animals under the
 

conditions of the test and indicate that exposure to the chemical
 

is a potential risk to man. The actual determination of the risk
 

to man from animal carcinogens requires a wider analysis.
 

CONTRIBUTORS; This bioassay of titanium dioxide was conducted by
 

Hazleton Laboratories America, Inc., Vienna, Virginia, initially
 

under direct contract to NCI and currently under a subcontract to
 

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

Testing Program.
 

The NCI project officers who were responsible for selecting the
 

protocols used in this bioassay were Drs. N. P Page^'^ and C.
 

Cuetol. The principal investigators were Drs. M. B. Powers^ and
 

R. W. Voelker^. Ms. K. J. Petrovics^ was responsible for data
 

management, and Mr. G. Najarian^ for animal care.
 

Histopathologic examinations were performed by Drs. D. A. Banas-*
 

and R. H. Habermann^ and reviewed by Dr. Voelker, and the
 

diagnoses included in this report represent their interpretation.
 

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

Mason Research Institute^. The statistical analyses were
 

performed by Dr. J. R. Joiner5 and Ms. P. L. Yong5, using methods
 

selected for the bioassay program by Dr. J. J. Gart6. Chemicals
 

used in this bioassay were analyzed at Midwest Research Institute
 

under the direction of Dr. E. Murrill^ and feed mixtures
 

containing the test chemical were analyzed at Hazleton
 

Laboratories by Dr. C. L. Guyton^ and Mr. E. Missaghi^. xhe
 

results of these analyses were reviewed by Dr. S. S. Olin5.
 

This report was prepared at Tracer Jitco5 in collaboration with
 

Hazleton Laboratories and NCI. Those responsible for the report
 

at Tracer Jitco were Dr. L. A. Campbell, Director of the Bioassay
 

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

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

Miller, Ms. L. A. Waitz, and Mr. W. D. Reichardt, bioscience
 

writers; and Dr. E. W. Gunberg, technical editor, assisted by Ms.
 

Y. E. Presley and Ms. P. J. Graboske.
 

The following other scientists at NCI were responsible for
 

evaluating the bioassay experiment, interpreting the results, and
 

reporting the findings: Dr. Kenneth C. Chu, Dr. Cipriano Cueto,
 

Jr., Dr. J. Fielding Douglas, Dr. Dawn G. Goodman**, Dr. Richard
 

A. Griesemer, Dr. Morton H. Levitt, Dr. Harry A. Milman, Dr.
 

Thomas W. Orme, Dr. Robert A. Squire9, Dr. Sherman Stinson, Dr.
 

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

^Carcinogenesis Testing Program, Division of Cancer Cause and
 

Prevention, National Cancer Institute, National Institutes of
 

Health, Bethesda, Maryland.
 

2Now with the Environmental Protection Agency, 401 M Street,
 

S.W., Washington, D.C.
 

3Hazleton Laboratories America, Inc., 9200 Leesburg Turnpike,
 

Vienna, Virginia.
 

Mason Research Institute, 1530 East Jefferson Street,
 

Rockville, Maryland.
 

IV
 
^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.
 

^Midwest Research Institute, 425 Volker Boulevard, Kansas City,
 

Missouri.
 

with Clement Associates, Inc., 1010 Wisconsin Avenue, N.W.,
 

Suite 660, Washington, D.C.
 

with the Division of Comparative Medicine, Johns Hopkins
 

University, School of Medicine, Traylor Building, Baltimore,
 

Maryland.
 
vi

 
SUMMARY
 

A bioassay of titanium dioxide for possible carcinogenicity was
 

conducted by administering the test chemical in feed to Fischer 344
 

rats and B6C3F1 mice.
 

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

administered titanium dioxide in the diet at one of two doses, either
 

25,000 or 50,000 ppm, for 103 weeks and then observed for 1
 

additional week. Matched controls consisted of 50 untreated rats of
 

each sex and 50 untreated mice of each sex. All surviving rats and
 

mice were killed at 104 weeks.
 

Administration of the titanium dioxide had no appreciable effect on
 

the mean body weights of rats or mice of either sex. With the
 

exception of white feces, there was no other clinical sign that was
 

judged to be related to the administration of titanium dioxide.
 

Survival of the rats and the male mice at the end of the bioassay was
 

not affected by the test chemical; mortality in female mice was dose
 

related. Sufficient numbers of dosed and control rats and mice of
 

each sex were at risk for development of late-appearing tumors.
 

In the female rats, C-cell adenomas or carcinomas of the thyroid
 

occurred at incidences that were dose related (P = 0.013), but were
 

not high enough (P = 0.043 for direct comparison of the high-dose
 

group with the control group) to meet the level of P = 0.025 required
 

by the Bonferroni criterion (controls 1/48, low- dose 0/47,
 

high-dose 6/44). Thus, these tumors of the thyroid were not
 

considered to be related to the administration of the test chemical.
 

In the male and female mice, no tumors occurred in dosed groups at
 

incidences that were significantly higher than those for
 

corresponding control groups.
 

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

dioxide was not carcinogenic by the oral route for Fischer 344 rats
 

or B6C3F1 mice.
 

vii
 
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 8
 

F. Designs of Chronic Studies 9
 

G. Clinical and Pathologic Examinations 9
 

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) 20
 

D. Statistical Analyses of Results (Rats) 21
 

IV. Results - Mice 25
 

A. Body Weights and Clinical Signs (Mice) 25
 

B. Survival (Mice) 25
 

C. Pathology (Mice) 28
 

D. Statistical Analyses of Results (Mice) 29
 

V. Discussion • 31
 

VI. Bibliography 35
 

APPENDIXES
 

Appendix A Summary of the Incidence of Neoplasms in
 

Rats Administered Titanium Dioxide in the Diet 39
 

Table Al Summary of the Incidence of Neoplasms in Male Rats
 

Administered Titanium Dioxide in the Diet 41
 

Table A2 Summary of the Incidence of Neoplasms in Female Rats
 

Administered Titanium Dioxide in the Diet 45
 

ix
 
Page 

Appendix B Summary of the Incidence of Neoplasms in Mice 

Administered Titanium Dioxide in the Diet..... 49 

Table Bl Summary of the Incidence of Neoplasms in Male Mice 

Administered Titanium Dioxide in the Diet..... 51 

Table B2 Summary of the Incidence of Neoplasms in Female 

Mice Administered Titanium Dioxide in the Diet 54 

Appendix C Summary of the Incidence of Nonneoplastic 

Lesions in Rats Administered Titanium Dioxide 

in the Diet 59 

Table Cl Summary of the Incidence of Nonneoplastic 

Lesions in Male Rats Administered Titanium Dioxide 

in the Diet 61 

Table C2 Summary of the Incidence of Nonneoplastic 

Lesions in Female Rats Administered Titanium Dioxide 

in the Diet 67 

Appendix D Summary of the Incidence of Nonneoplastic 

Lesions in Mice Administered Titanium Dioxide 

in the Diet 73 

Table Dl Summary of the Incidence of Nonneoplastic 

Lesions in Male Mice Administered Titanium Dioxide 

in the Diet 75 

Table D2 Summary of the Incidence of Nonneoplastic 

Lesions in Female Mice Administered Titanium Dioxide 

in the Diet 79 

Appendix E Analyses of the Incidence of Primary Tumors 

in Rats Administered Titanium Dioxide in the Diet.. 83 

Table El Analyses of the Incidence of Primary Tumors in Male 

Rats Administered Titanium Dioxide in the Diet 85 

Table E2 Analyses of the Incidence of Primary Tumors in Female 

Rats Administered Titanium Dioxide in the Diet 92 

Appendix F Analyses of the Incidence of Primary Tumors 

in Mice Administered Titanium Dioxide in the Diet.. 99 

x
 
Pace 

Table Fl Analyses of the Incidence of Primary Tumors in Male 

Mice Administered Titanium Dioxide in the Diet 101 

Table F2 Analyses of the Incidence of Primary Tumors in Female 

Mice Administered Titanium Dioxide in the Diet..... 104 

Appendix G Analysis of Formulated Diets for 

Concentrations of Titanium Dioxide 109 

TABLES 

Table 1 Design of Titanium Dioxide Chronic Feeding 

Studies in Rats and Mice 10 

FIGURES 

Figure 1 Growth Curves for Rats Administered Titanium 

Dioxide in the Diet 18 

Figure 2 Survival Curves for Rats Administered Titanium 

Dioxide in the Diet 19 

Figure 3 Growth Curves for Mice Administered Titanium 

Dioxide in the Diet 26 

Figure 4 Survival Curves for Mice Administered Titanium 

Dioxide in the Diet 27 

xi
 
xii

 
I. INTRODUCTION
 

Titanium dioxide (CAS 13463-67-7; NCI C04240) is a white pigment
 

possessing great covering or opacifying power. It exists in
 

three crystalline forms: anatase, brookite, and rutile, but only
 

the anatase variety is used as a food color additive (Noonan,
 

1975). Titanium dioxide has been in use since 1918, although the
 

market was greatly expanded after 1948 when the need for titanium
 

led to technological advancements in ore processing (Bomberger,
 

1969). In 1977, the production volume for titanium dioxide in
 

the United States was 800,000 tons. The majority of this was
 

produced for pigmentary applications; 50% for paints and other
 

protective coatings, 20% for paper, and 12% for plastics (Greek,
 

1977). Titanium dioxide is used as a color additive in foods
 

(anatase) (FDA, 1976a), and in topical and oral drugs (FDA,
 

1976b). In the cosmetics industry, it is used as a whitener in a
 

wide variety of products including aftershave powders, bath
 

powders, face powders, depilatories, deodorants, fingernail
 

coatings, beauty masks, cleansing creams, eye makeup, foundations, lipsticks, and skin lighteners (Bell, 1972; Saute, 1972;
 

Farber, 1972; Barry, 1972; Doviak, 1972; Fiedler, 1972; Lauffer,
 

1972; Wetterhahn, 1972; Plechner, 1972; Shevlin, 1972). It has
 

been formulated in sunscreens as a physical light-blocking agent
 

(MacLeod and Frain-Bell, 1975).
 
Although its refractive index accounts for its most important use
 

as a white pigment, titanium dioxide has important nonpigmentary
 

uses. These include use as a catalyst, a dielectric in
 

capacitors, an anticorrosive in vitreous enamel coatings, a
 

welding rod coating, a source of titanium metal, and a gem
 

(Stanley, 1969).
 

A titanium coordination complex was shown to be carcinogenic in
 

rats and mice by intramuscular injection (Furst and Haro, 1970).
 

The compound tested was a metallocene, a sandwich arrangement of
 

the metal between two cyclopentadiene molecules. Titanium
 

dioxide was selected for study in the Carcinogenesis Testing
 

Program because this result stimulated an interest in the
 

carcinogenicity of other titanium compounds, such as the dioxide,
 

which was in wide commercial use.
 
II. MATERIALS AND METHODS
 

A. Chemical
 

Three lots of titanium dioxide anatase, designated Unitane®
 

0-220, were obtained from American Cyanamid Company, Wayne, New
 

Jersey. The manufacturer's specification was 98% minimum Ti02­

The identity and purity of each batch was determined by Midwest
 

Research Institute, Kansas City, Missouri. The moisture content
 

of each batch was < 0.4%.
 

Atomic absorption analysis for titanium matched the theoretical
 

value in Lot No. 402110C46 (used in the 90-day Subchronic
 

toxicity studies), was about 1.6% high in Lot No. 402129A29 (used
 

from weeks 0-51 in the chronic studies), and was 1.5% low in Lot
 

No. 402129B20 (used from weeks 52-103 in the chronic studies).
 

Lot No. 402110C46 also contained 0.15% aluminum by atomic
 

absorption. Other impurities in the 0.1-1.0% range (identified
 

by spark source mass spectrometry) were niobium and chlorine (Lot
 

Nos. 402129A29 and 402129B20), phosphorus (all three lots),
 

silicon (Lot Nos. 402110C46 and 402129B20), calcium (Lot No.
 

402110C46), and potassium (Lot No. 402129B20). Infrared spectra
 

of all lots were identical to the spectrum given in the literature (Kammori et al., 1967).
 
B. Dietary Preparation
 

A quantity of the bulk chemical was sifted to remove any large
 

particles, and the amount required for each dose mixture was
 

weighed out under a hood. This quantity was then incorporated
 

into the basal diet of Wayne® Lab Blox animal meal (Allied Mills,
 

Inc., Chicago, 111.) by thorough mixing in a Patterson-Kelly
 

twin-shell blender equipped with an intensifier bar. Corn oil
 

(Duke's, C. F. Sauer Co., Richmond, Va.) was added to the dosed
 

diets and to the diets for the matched controls to give a final
 

concentration of 2%. Diets were prepared once per week and
 

stored at room temperature until used.
 

As a quality control measure, selected samples from freshly
 

prepared mixtures were stored at 4°C and aliquots from these
 

samples, containing approximately 50 micrograms of titanium
 

dioxide were later analyzed for titanium dioxide by the method
 

described by the Association of Official Analytical Chemists
 

(1975). The results of these analyses are summarized in Appendix
 

G. At each dietary concentration, the mean value obtained by the
 

analytical method was within 4% of the theoretical value,
 

although the coefficient of variation was nearly 30%. This
 

variation appears to be due to the difficulty in obtaining a
 

homogeneous mix of a fine powder in feed.
 
C. Animals
 

Fischer 344 rats and B6C3F1 mice were obtained from the Frederick
 

Cancer Research Center, Frederick, Maryland, through contracts
 

with the Division of Cancer Treatment, National Cancer Institute.
 

On arrival at the laboratory, the rats were quarantined for 30
 

days and the mice for 15 days, determined to be free from
 

observable disease or parasites, and assigned to the dosed or
 

control groups based on initial individual body weight, so that
 

the of mean animal body weights per group were approximately
 

equal.
 

D. Animal Maintenance
 

All animals were housed in temperature- and humidity-controlled
 

rooms. The temperature was generally maintained at 20-24°C and
 

the relative humidity at 45-55%. Incoming air was filtered
 

through 2-inch-thick disposable fiberglass filters at a rate that
 

allowed 12 changes of room air per hour. Lighting was provided
 

on a 12-hour-per-day cycle.
 

The rats and mice were each housed in polycarbonate cages covered
 

with stainless steel cage lids and non-woven fiber filter bonnets
 

(Filtek, Appleton, Wis.). The rats were initially housed five
 

per cage; however, at week 48, the males were divided into groups
 
of two or three per cage. The mice were housed five per cage
 

throughout the study.
 

All cages were furnished with heat-treated hardwood chip bedding
 

(Sani-Chips®, Shurfire Products Corporation, Beltsville,
 

Maryland); the bedding was changed twice per week. Diets and
 

well water were made available ad libitum. Food hoppers were
 

refilled twice per week.
 

Cages, water bottles, and sipper tubes were sanitized at 81°C
 

twice per week, feed hoppers once per week, and cage racks once
 

per month. An industrial dish washer was used for the water
 

bottles, and sipper tubes; a cage and rack washer was used for
 

the food hoppers, cages, and racks. Acclaim®, a chlorinated
 

detergent, was used. When racks were washed, clean racks
 

containing cages of animals were randomly repositioned in the
 

rooms.
 

The rats and mice were housed in separate rooms. Control animals
 

were housed in the same room as the respective dosed animals.
 

Rats administered diets containing titanium dioxide were
 

maintained in the same room as rats being administered the
 

following chemicals:
 
Rats
 

Feed Studies
 

(CAS 89-78-1) dl-menthol
 

(CAS 119-53-9) benzoin
 

(CAS 120-61-6) dimethylterephthalate
 

Gavage Studies
 

(CAS 127-69-5) sulfisoxazole
 

(CAS 7488-56-4) selenium disulfide
 

(CAS 108-60-1) bischloroisopropyl ether
 

Drinking Water Studies
 

(CAS 108-95-2) phenol
 

At week 48, the rats fed titanium dioxide, together with those
 

fed dl-menthol and those fed benzoin, were moved to a separate
 

room for the remainder of the bioassay.
 

Mice administered diets containing titanium dioxide were
 

maintained in the same room as mice being administered the
 

following chemicals:
 

Mice
 

Feed Studies
 

(CAS 89-78-1) dl-menthol
 

(CAS 119-53-9) benzoin
 

(CAS 120-61-6) dimethylterephthalate
 

Gavage Studies
 

(CAS 127-69-5) sulfisoxazole
 

(CAS 7488-56-4) selenium disulfide
 

(CAS 108-60-1) bischloroisopropyl ether
 
Drlriklng Water Studies
 

(C&S;f108-95-2) phenol
 

The control groups of rats and mice used for the titanium dioxide
 

studies were used also for the dl-menthol studies. The control
 

groups were maintained in the same rooms with the dosed groups.
 

E. Subchronic Studies
 

Subchronic feeding studies were conducted to estimate the maximum
 

tolerated doses of titanium dioxide, on the basis of which two
 

concentrations (hereinafter referred to as "low" and "high"
 

doses) were selected for administration in the chronic studies.
 

On the basis of results from a 14-day (repeated dose) oral
 

range-finding study, doses of 6,250, 12,500, 25,000, 50,000, or
 

100,000 ppm were administered in the diet in the Subchronic
 

studies. Ten males and 10 females of each species were administered the test chemical at each dose, and 10 males and 10 females
 

received basal diets. Dosed animals received the' test compound
 

for 13 consecutive weeks.
 

In both the rat studies and the mouse studies, there were no
 

deaths, and dosed animals had mean body weight gains that were
 

comparable to those of the controls. No gross or microscopic
 

pathology was found that could be related to the administration
 

of the test chemical in either the rats or the mice. On the
 
basis of these results, the high dose for both the rats and mice
 

in the chronic studies was set at 50,000 ppm, the maximum amount
 

allowed for use in chronic bioassays in the Carcinogenesis
 

Testing Program, and the low dose was set at 25,000 ppm.
 

F. Designs of Chronic Studies
 

The test groups, doses administered, and times on study of the
 

chronic feeding studies are shown in table 1.
 

G. Clinical and Pathological Examinations
 

All animals were observed twice daily for signs of toxicity.
 

Clinical signs and the presence of palpable masses were recorded
 

every week. Mean body weights and food consumption were
 

recorded every 2 weeks for the first 12 weeks and every month
 

thereafter.
 

Animals that were moribund and those that survived to the
 

termination of the study were killed by exsanguination under
 

sodium pentobarbital anesthesia (Diabutal®, Diamond Laboratories,
 

Inc., Des Moines, Iowa). The sodium pentobarbital was injected
 

intraperitoneally at a volume of 0.3 to 0.5 ml for the rats and
 

0.03 to 0.05 ml for the mice.
 

The pathologic evaluation consisted of gross and microscopic
 

examination of major tissues, major organs, and all gross lesions
 
Table 1. Design of Titanium Dioxide Chronic Feeding Studies
 

in Rats and Mice
 

Sex and 

Test 

Group 

Initial 

No. of 

Animals3 

Titanium 

Dioxide 

Dosesb 

(ppm) 

Time 

Dosed 

(weeks) 

on Study 

Observed 

(weeks) 

Male 

Matched-Control 50 0 104 

Low -Dose 50 25,000 103 1 

High-Dose 50 50,000 103 1 

Female 

Matched-Control 50 0 104 

Low-Dose 50 25,000 103 1 

High-Dose 50 50,000 103 1 

a

Rats were 64 days of age and mice were 36 days of age when placed
 

on study.
 

test chemical was administered 7 days per week in a diet
 

containing 2% corn oil. The control groups received only
 

2% corn oil in the diet. Diets were available ad libitum.
 

10
 
from killed animals and from animals found dead. The tissues
 

were preserved in 10% buffered formalin, embedded in paraffin,
 

sectioned, and stained with hematoxylin and eosin. The following
 

tissues were examined microscopically: brain (frontal cortex and
 

basal ganglia, parietal cortex and thalamus, and cerebellum and
 

pons), pituitary, spinal cord (if neurologic signs were present),
 

eyes (if grossly abnormal), esophagus, trachea, salivary glands,
 

mandibular lymph node, thyroid, parathyroid, heart, thymus, lungs
 

and mainstem bronchi, liver, gallbladder (mice), pancreas,
 

spleen, kidney, adrenal, stomach, small intestine, colon, urinary
 

bladder, prostate or uterus, testes or ovaries, sternebrae,
 

femur, or vertebrae including marrow, mammary gland, tissue
 

masses, and any gross lesion.
 

A few tissues from some animals were not examined, particularly
 

from those animals that died early. Also, some animals may have
 

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

state 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
 

study in each group.
 

11
 
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 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.
 

12
 
One-tailed P values have been reported for all tests except the
 

departure from linearity test, which is only reported when its
 

two-tailed P value is less than 0.05.
 

The incidence of neoplastic or nonneoplastic lesions has been
 

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

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

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

the denominators included only those animals for which that site
 

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

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

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

consist of the numbers of animals necropsied.
 

The purpose of the statistical analyses of tumor incidence is to
 

determine whether animals receiving the test chemical developed a
 

significantly higher proportion of tumors than did the control
 

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

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

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

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

compared simultaneously with those for a control group, a
 

correction to ensure an overall significance level of 0.05 may be
 

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

13
 
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 when
 

appropriate. Under the assumption of a linear trend, this test
 

determines if the slope of the dose-response curve is different
 

from zero at the one-tailed 0.05 level of significance. Unless
 

otherwise noted, the direction of the significant trend is a
 

positive dose relationship. This method also provides a
 

two-tailed test of departure from linear trend.
 

A time-adjusted analysis was applied when numerous early deaths
 

resulted from causes that were not associated with the formation
 

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

first tumor was observed were excluded by basing the statistical
 

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

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

such an early tumor was found, comparisons were based exclusively
 

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

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

obtained, the standard procedures for analyses of the incidence
 

14
 
of tumors (Fisher exact tests, Cochran-Armitage tests, etc.) were
 

followed.
 

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

incidence of tumors. Curves of the proportions surviving without
 

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

The week during which an animal died naturally or was sacrificed
 

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

methods of comparing these curves were used for two groups;
 

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

groups. The statistical tests for the incidence of tumors which
 

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

noted, in the direction of a positive dose relationship. Significant departures from linearity (P < 0.05, two-tailed test) were
 

also noted.
 

The approximate 95 percent confidence interval for the relative
 

risk of each dosed group compared with 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
 

dosed 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 dosed group and the proportion in a control
 

15
 
group corresponds to a relative risk of unity. Values in excess
 

of unity represent the condition of a larger proportion in the
 

dosed group than in the control.
 

The lower and upper limits of the confidence interval of the
 

relative risk have been included in the tables of statistical
 

analyses. The interpretation of the limits is that in
 

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

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

control group would be within the interval calculated from the
 

experiment. When the lower limit of the confidence interval is
 

greater than one, it can be inferred that a statistically
 

significant result (P < 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)
 

Administration of titanium dioxide had no appreciable effect on
 

the mean body weights of either the male or the female rats
 

(figure 1). The clinical signs observed in the dosed groups were
 

generally comparable to those of the control group and included
 

alopecia, sores, and lacrimating, protruding, and/or pale eyes.
 

From weeks 88 through 104, hunched appearance and thinness were
 

noted more frequently in the dosed males and females than in
 

their respective controls. Urine stains were noted on the dosed
 

rats of each sex. Animals in all of the dosed groups had white
 

feces.
 

B. Survival (Rats)
 

The Kaplan and Meier curves estimating the probabilities of
 

survival for male and female rats administered titanium dioxide
 

in the diet at the doses of this bioassay, together with those of
 

the matched controls, are shown in figure 2. The result of the
 

Tarone test for dose-related trend in mortality is not
 

significant in either sex.
 

In the male rats, 36/50 (72%) of the high-dose group, 37/50 (74%)
 

of the low-dose group, and 31/50 (62%) of the matched controls
 

17
 
B

 

1

 300­

ili 

g

>. 250 ­

Q

O 

m 

z 200 ­

MALE RATS 

D MATCHED CONTROL 

O LOW DOSE 

A HIGH DOSE 

10 20 40 50 60 70 80 90 100 110 

TIME ON STUDY (WEEKS) 

O Jau 

lT 

2 300 UJ A 

D 

Q 250 

O o m 

z 

< 200 ­

150 ­ fi FEMALE RATS 11 D MATCHED CONTROL 

100 ­ O LOW DOSE 

A HIGH DOSE 

10 20 40 50 60 70 80 90 100 110 

TIME ON STUDY (WEEKS) 

Figure 1. Growth Curves for Rats Administered Titanium Dioxide in the Diet 

18 
PROBABILIT

Y OF SURVIVAL PROBABILITY OF SURV

> O O O C 

(J1 O) O O S 

1 1 

CD ro 

V)

I O o n

 I c ^

i! 

c-> 

I 

2 >H *" o <" 

i?«• 

3s. a. 3. =' 

C/9 

5 cc B9 =3 

O 

X CD 

O 

re' 
were alive at week 104. In the females, 34/50 (68%) of the
 

high-dose group, 36/50 (72%) of the low-dose group, and 36/50
 

(72%) of the matched controls were alive at week 104. Sufficient
 

numbers of rats of each sex were at risk for the development of
 

late-appearing tumors.
 

C. Pathology (Rats)
 

Histopathologic findings on neoplasms in rats are summarized in
 

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

are summarized in Appendix C, tables Cl and C2.
 

Each of the tumor types listed has been encountered previously as
 

a spontaneous lesion, and with only a few exceptions, occurred
 

with no appreciable difference in frequency between control and
 

dosed groups. In the male rats, pheochromocytomas of the adrenal
 

medulla and fibromas of the subcutaneous tissue were observed
 

with slightly greater frequency in dosed groups; however, the
 

number of neoplasms was compatible with incidences of these
 

tumors in historical-control rats of this age and strain. In the
 

female rats, endometrial stromal polyps were observed more
 

frequently in dosed groups than in control groups, but the
 

incidence of lesions is comparable with that in historical
 

controls. Thus, these lesions are not considered to be related
 

to administration of the test chemical.
 

20
 
Inflammatory, degenerative, and hyperplastic lesions that
 

occurred were similar in number and kind to those naturally
 

occurring lesions found in aged Fischer 344 rats.
 

Based on the histopathologic examination, titanium dioxide was
 

neither toxic nor carcinogenic to Fischer 344 rats under the
 

conditions of this bioassay.
 

D. Statistical Analyses of Results (Rats)
 

Tables El and E2 in Appendix E contain the statistical analyses
 

of the incidences of those primary tumors that occurred in at
 

least two animals of one group and at an incidence of at least 5%
 

in one or more than one group.
 

In the male rats, three keratoacanthomas of the skin were
 

observed in the high-dose group, but none in the other two groups
 

studied. Although the result of the Fisher exact test fpr direct
 

comparison of the incidence in the high-dos^ group with that'in
 

the control group is not significant, the result of the
 

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

incidence of these tumors is significant (P = 0.038).
 

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

positive dose-related trend in the combined incidence of C-cell
 

/'
 

adenomas or carcinomas of the thyroid is significant (P = 0.013).
 

21
 
A significant (P = 0.044) departure from linear trend is observed
 

due to the relatively steep increase in this incidence of tumors
 

observed in the high-dose group. The result of the Fisher exact
 

test comparing the incidence in the high-dose group with that in
 

the control group indicates a P value of 0.043, which is above
 

the 0.025 level required for significance when the Bonferroni
 

inequality criterion is used for multiple comparison. The
 

results of statistical tests of the incidence of these tumors in
 

the male rats are not significant.
 

The Fisher exact comparison of the incidence of eridometrial
 

stromal polyps of the uterus/endometrium in the low-dose females
 

with that in the corresponding controls indicates a P value of
 

0.045, which is above the 0.025 level required for significance
 

when the Bonferroni inequality criterion is used for multiple
 

comparison. The incidence of these tumors in the high-dose group
 

is not significant when compared with that in the control group,
 

and the result of the Cochran-Armitage test for dose-related
 

trend also is not significant.
 

Significant results in the negative direction are observed in the
 

incidence of leukemia in male rats, in which the incidence in the
 

control group exceeds the incidences in the dosed groups.
 

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

22
 
in the tables, the value of one is included; this indicates the
 

absence of significant positive results. It should also be noted
 

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

indicating the theoretical possibility of the induction of tumors
 

by titanium dioxide, which could not be detected under the
 

conditions of this test.
 

23
 
24

 
IV. RESULTS - MICE
 

A. Body Weights and Clinical Signs (Mice)
 

Administration of titanium dioxide had no appreciable effect on
 

the mean body weights of either the male or the female mice
 

(figure 3). The clinical signs observed in the dosed groups were
 

comparable with those of the control group and included protrusion of the eyes, bloody crust surrounding the eyes, palpable
 

nodules, tissue masses and/or wart-like lesions, localized sores,
 

irritation and swelling of the testes, hunched appearance, and/or
 

thinness. Alopecia (localized or generalized) was noted in all
 

the control and dosed groups; however, more was observed in the
 

control females than in the dosed females. The areas of alopecia
 

were primarily located around the nose and head and progressed to
 

generalized alopecia in some of the animals. The type of feed-


hopper used in this study may have caused the^alopecia around the
 

nose. Animals in all of the dosed groups had white feces.
 

B. Survival (Mice)
 

The Kaplan and Meier curves estimating the probabilities of
 

survival for male and female mice administered titanium dioxide
 

in the diet at the doses of this bioassay, together with those of/'
 

the matched controls, are shown in figure 4. In male mice, the
 

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

25
 
UJ 

g 

o to 

<

30 H 

 20 ­

e a n n 

10 20 30 40 50 60 70 

TIME ON STUDY (WEEKS) 

MALE MICE 

D MATCHED CONTROL 

O LOW DOSE 

A HIGH DOSE 

100 110 

_

(9 

 35 

A A A 

a 

A 

n a D a 

a 

A 

2 

>­ 25 a a 

Q 

O 

m 

Z 

FEMALE MICE 

D MATCHED CONTROL 

O LOW DOSE 

A HIGH DOSE 

100 110 

TIME ON STUDY (WEEKS) 

Figure 3. Growth Curves for Mice Administered Titanium Dioxide in the Diet 

26 
u A.. \-l^ -J, ti ~~&Qi, c HV "A 

b—&-• 

5 i 

^H 

7, ^ LW^1

 ­

( U

 

_J 

> 

(A 

u. 

> 

H 

j 

CD 

0 

cc 

M \LE Ml CE 

D MAI FCHED CO 

O LOV IDOSE 

A HIG H DOSE 

0 10 20 30 40 50 60 70 80 90 100 

TIME ON STUDY (WEEKS) 

T ) — — ~~bA- ' 1 6— •J. ^0 i 

i * 

"•\.. ^ 

A

^i.

< \ > 

to 

u. 

O 

H 

Zi 

m 

a 

0 

cc 

CL 

FEI\ 1ALE M ICE 

a MA rcHEDCO 

O LOV (DOSE 

A Hie HDOSE 

10 20 30 40 50 60 70 80 90 100 110 

TIME ON STUDY (WEEKS) 

Figure 4. Survival Curves for Mice Administered Titanium Dioxide in the Diet 

27 
not significant, but in females, the result of the Tarone test
 

shows a significant (P = 0.001) positive dose-related trend.
 

Forty out of fifty (80%) of the high-dose males, 40/50 (80%) of
 

the low-dose males, and 32/50 (64%) of the matched-control males
 

were still alive at week 104. In females, 33/50 (66%) of the
 

high-dose group, 39/50 (78%) of the low-dose group, and 45/50
 

(90%) of the matched controls were alive at week 104. Sufficient
 

numbers of mice of each sex were at risk for the development of
 

late-appearing tumors.
 

C« Pathology (Mice)
 

Histopathologic findings on neoplasms in mice are summarized in
 

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

are summarized in Appendix D, tables Dl and D2.
 

A low incidence of neoplasia was observed in both the control
 

mice and dosed mice. These neoplasms were of the usual number
 

and type observed in mice of this age and strain. A slightly
 

increased number of hepatocellular carcinomas was observed in the
 

high-dose males; however, the incidence of tumors was not
 

increased over that observed in historical-control groups of mice
 

of this age and strain.
 

28
 
Degenerative, proliferative, and inflammatory lesions were also
 

of the usual number and kind observed in aged B6C3F1 mice.
 

Based on the histopathologic examination, titanium dioxide was
 

neither toxic nor carcinogenic to B6C3F1 mice under the
 

conditions of this bioassay.
 

D. Statistical Analyses of Results (Mice)
 

Tables Fl and F2 in Appendix F contain the statistical analyses
 

of the incidences of those primary tumors that occurred in at
 

least two animals of one group and at an incidence of at least 5%
 

in one or more than one group.
 

The results of the Cochran-Armitage test for positive dose-


related trend in incidences of tumors and those of the Fisher
 

exact test for higher incidences of tumors in dosed groups than
 

in control groups are not significant for any type of tumor
 

occurring in either sex. A significant trend (P = 0.037) in the
 

negative direction is observed in the incidence of follicularcell adenomas of the thyroid in female mice, in which the
 

incidence in the control group exceeds the incidences in the
 

dosed groups. The results of the Fisher exact test (P = 0.035 in
 

the negative direction) for the comparison of the incidence of
 

combined lymphomas and leukemias in the female low-dose group
 

with that in the corresponding controls are above that of 0.025
 

29
 
required for significance in multiple comparisons. This negative
 

result may be accounted for by the difference in survival, since
 

the dosed animals did not live as long as the control animals.
 

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

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

absence of significant positive results. It should also be noted
 

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

indicating the theoretical possibility of the induction of tumors
 

by titanium dioxide, which could not be detected under the
 

conditions of this test.
 

30
 
DISCUSSION
 

Based on growth rate, mortality, and other clinical signs, there
 

was essentially no evidence of toxicity of titanium dioxide in
 

the dosed rats or dosed mice. Administration of the test
 

chemical had no appreciable effect on the mean body weights of
 

either male or female rats with the exception of white feces,
 

there was no other clinical sign that was judged to be related to
 

the administration of titanium dioxide. Survival of the male and
 

female rats and of the male mice at the end of the bioassay was
 

not affected by the test chemical; survival of the high-dose
 

female mice was shorter than that of the low-dose and control
 

groups. Sufficient numbers of dosed and control rats and mice of
 

each sex were at risk for development of late-appearing tumors.
 

Although little or no effect on weight gain and survival could be
 

attributed to titanium dioxide, except in female mice, the doses
 

were considered to approximate the maximum that could be
 

administered and still not affect the nutritional quality of the
 

diet. This is consistent with the guidelines for carcinogenesis
 

bioassay in the Carcinogenesis Testing Program (Sontag et al.,
 

1976).
 

In the female rats, C-cell adenomas or carcinomas of the thyroid
 

occurred at incidences that were dose related (P = 0.013), but
 

not high enough (P = 0.043 for direct comparison of the high-dose
 

31
 
group with the control group) to meet the level of P = 0.025
 

required by the Bonferroni criterion (controls 1/48, low-dose
 

0/47, high-dose 6/44). Thus, the tumors of the thyroid are not
 

considered to be related to administration of the test chemical.
 

Also in the females, endometrial stromal polyps of the
 

endometrium/uterus occurred at. higher incidences in the dosed
 

groups than in the controls, but the incidences were not dose
 

related and were not high enough (P = 0.045 for direct comparison
 

of the low-dose group with the control group) to meet the
 

requirements of the Bonferroni criterion (controls 7/50, low-dose
 

15/50, high-dose 10/50),
 

In the male and female mice, no tumors occurred in dosed groups
 

at incidences that were significantly higher than those in
 

corresponding control groups.
 

In other studies, no adverse pulmonary effects were foun4' when
 

Wistar rats were administered titanium dioxide by inhalation
 

(Christie et al., 1963), and no evidence of carcinogenicity was
 

found when Swiss albino mice were administered potassium titanium
 

oxalate at a concentration of 5 ppm titanium in drinking water
 

for the life span of the mice (Schroeder et al. , 1964). When
 

titanium was administered to Fischer 344 rats and to DBA/2,
 

C57BL/6, or Swiss albino mice by intramuscular injection as
 

titanocene, a complex of titanium with cyclopentadiene, a variety
 

32
 
of neoplasms developed at the site of injection and in organs
 

some distance away (Furst and Haro, 1969, 1970).
 

It is concluded that under the conditions of this bioassay,
 

titanium dioxide was not carcinogenic for Fischer 344 rats or
 

B6C3F1 mice.
 

33
 
34

 
VI. BIBLIOGRAPHY
 

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

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

Association of Official Analytical Chemists, Official Methods of
 

Analysis _of the Asociation of Official Analytical Chemists,
 

12th edition, Horwitz, W., ed., Association of Offical
 

Analytical Chemists, Washington, B.C., 1975, p. 7.
 

Barry, R. H., Depilatories. In: Cosmetics - Science and
 

Technology, Vol. _2, Balsam, M. S. and Sagarin, E. , eds., New
 

York, 1972, pp. 49 and 57.
 

Bell, S. A., Preshave and aftershave preparations. In:
 

Cosmetics - Science and Technology, Vol. _2_, Balsam, M. S.
 

and Sagarin, E., eds., Wiley-Interscience, New York, 1972,
 

p. 33.
 

Berenblum, I. , ed., Carcinogenicity Testing, A_ Report of the
 

Panel on Carcinogenicity of the Cancer Research Commission
 

of the UICC, Vol. _2, International Union Against Cancer,
 

Geneva, 1969.
 

Bomberger, H. B., Titanium and titanium alloys. In: Kirk - Othmer
 

Encyclopedia £f Chemical Technology, Vol. 20, Mark, H. F. ,
 

McKetta, J. J. , Jr., and Othmer, D. F., eds., Interscience
 

Publishers, Inc., New York, 1969, pp. 347-379.
 

Christie, H. , MacKay, R. J. , and Fisher, A. M., Pulmonary effects
 

of inhalation of titanium dioxide by rats. Amer. Ind. Hyg.
 

ASSOC. J. 24:42-46, 1963.
 

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

Soc. B 34:187-220. 1972.
 

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

1970, pp. 48-52.
 

Doviak, W. C., Nail lacquers and removers. In: Cosmetics ­

Science and Technology, Vol. _2, Balsam, M. S. and Sagarin,
 

E., eds., Wiley-Interscience, New York, 1972, pp. 527-529.
 

Farber, L., Face powders. In: Cosmetics - Science and Technology,
 

Vol. _1, Balsam, M. S. and Sagarin, E. , eds., Wiley-


Interscience, New York, 1972, pp. 338-339.
 

35
 
Fielder, J. G. , Foundation makeup. In: Cosmetics - Science and
 

Technology, Vol. _1, Balsam, M. S. and Sagarin, E., eds.,
 

Wiley-Interscience, New York, 1972, pp. 317-318.
 

Food and Drug Administration, 21 CFR 8.316, 1976a.
 

Food and Drug Administration, 21 CFR 8.6005, 1976b.
 

Furst, A. and Haro, R. 1., Carcinogenicity of metal pi-complex
 

compounds: metallocenes. In: Tenth International Cancer
 

Congress - Abstracts, Houston, Tex., May 22-29, 1970, p. 28.
 

Furst A. and Haro, R. T. , A survey of metal carcinogenesis.
 

Progr. Exp. Tumor Res. 12:102-133, 1969.
 

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

significance tests, confidence limits and adjustments for
 

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

1971.
 

Greek, B. F., Two major pigments move into better times. C & EN
 

_55 (24): 10-11, 1977.
 

Kammori, 0., Yamaguchi, N., and Sato, K. , Application of infrared
 

absorption spectrum to studies on iron and steel. I.
 

Infrared absorption spectra of metal oxides, Bunseki Kagaku
 

,16:1050-1955, 1967.
 

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

incomplete observations. J. Amer. Statist. Assoc.
 

_5_3:457-481, 1958.
 

Lauffer, P. G. I., Lipsticks. In: Cosmetics - Science and
 

Technology, Vol. _!_, Balsam, M. S. and Sagarin, E., eds.,
 

Wiley-Interscience, New York, 1972, p. 370.
 

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.
 

MacLeod, T. M. and Frain-Bell, W., A study of physical light
 

screening agents. Brit. J. Dermat. 92:149-156, 1975.
 

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

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

36
 
Noonan, J., Color additives in food. In: Handbook of Food
 

Additives, Second Edition, Furia, T. E., ed., CRC Press,
 

Cleveland, Ohio, 1975, pp. 603-604.
 

Plechner, S. , Antiperspirants and deodorants. In: Cosmetics ­

Science and Technology, Vol. _2, Balsam, M. S. and Sagarin,
 

E., eds., Wiley-Interscience, New York, 1972, p. 388.
 

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.
 

Saute, R. E., Bath preparations. In: Cosmetics - Science and
 

Technology, Vol. _2_, Balsam, M. S. and Sagarin, E., eds.,
 

Wiley-Interscience, New York, 1972, p. 514.
 

Schroeder, H. A., Balassa, J. J., and Vinton, W. H., Jr.,
 

Chromium, lead, cadmium, nickel, and titanium in mice:
 

effect on mortality, tumors and tissue levels. J. Nutrition
 

j$3_:239-250, 1964.
 

Shevlin, E. J. , Skin lighteners and bleach creams. In:
 

Cosmetics - Science and Technology, Vol. _1_, Balsam, M. S.
 

and Sagarin, E. , eds., Wiley-Interscience, New York, 1972,
 

p. 227.
 

Sontag, J. M., Page, N. P., and Saffiotti, V., Guidelines for
 

Carcinogen Bioassay in Small Rodents. Carcinogenesis
 

Program, Division of Cancer Cause and Prevention, National
 

Cancer Institute, Bethesda, Md., 1976.
 

Stanley, R. H. , Titanium compounds (inorganic). In: Kirk - Othmer
 

Encyclopedia _of_ Chemical Technology, Vol. 20, Mark, H. F.,
 

McKetta, J. J. , Jr., and Othmer, D. F., eds., Interscience
 

Publishers, Inc., New York, 1969, pp. 347-379.
 

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

j>2(3):679-682, 1975.
 

Wetterhahn, J., Eye makeup. In: Cosmetics - Science and
 

Technology, Vol. J_, Balsam, M. S. and Sagarin, E., eds.,
 

Wiley-Interscience, New York, 1972, p. 397.
 

37
 
38

 
APPENDIX A
 

SUMMARY OF THE INCIDENCE OF NEOPLASMS IN
 

RATS ADMINISTERED TITANIUM DIOXIDE IN THE DIET
 

39
 
40

 
TABLE A1.

 

SUMMARY OF THE INCIDENCE OF NEOPLASMS IN MALE RATS 

ADMINISTERED TITANIUM DIOXIDE IN THE DIET 

1WATCHED 

(SOIMTROL LOW DOSE HIGH DOSE 

ANIMALS INITIALLY IN STUDY 50 50 50 

ANIMAL S NECROrSISD 49 50 50 

ANIMAL S EXAMINE D HI STOPATHOLOGIC ALL Y 49 50 50 

INTEGUMENTAR Y SYSTEM 

*SKIN (49) (50) (50) 

SQUAMOU S CELL PAPILLOM A 1 (2%) 

SQUAMOUS CELL CARCINOM A 1 (2%) 2 (14%) 

BASAL-CELi, CARCINOMA 1 (2%) 

KERATOACAdTHOB A 3 (6%) 

*SUBCUT TISSJE (49) (50) (50) 

SQUAMOUS CELL PAPILLOMA 1 (2%) 

SQUAMOUS CELL CARCINOMA 1 (2%) 

BASAL-CELL CARCINOM A 1 (2%) 

SARCOMA , wO S 1 (2%) 

FIBROMA 1 (2%) 5 (10%) 5 (1055) 

FIBROSARGJMA 1 (2%) 2 (4%) 

LIPOM A 1 (2%) 

HEMANGIOSARCOM A 1 (2%) 

HEMANGIOPERICYTOMA , MALIGNAN T 1 (255) 

R3SPIRATORY SYSTEM 

*LUNG (49) (50) (49) 

HEPATOCELiULAfi CARCINOMA, BETAST 1 (2*) 

HEBANGIOPE8ICYTOMA, BETASTATIC 1 (2*) 

HEBATOPOIETIC SYSTEM 

J *MU1TIPLE ORGAN S (49) (50) (50) 

GRANOLOCYJIC LEUKEBIA 2 (4X) 1 J2S) 

BOHOCYTIC LEUKEHIA 14 (29S) f~ ,-•(, (12*) 5 (10K) 

ISP1EEN (49) (50) (50) 

HEMANGIOSARCOHA 1 1281 3_I£S1 _ 

t NUMBER OF AfllBALS WITH TISSDE EXAMINED HICROSCOPICALLY 

* NUMBER OF AUIMALS NECHOPSIED 

41 
TABLE A1. MALE RATS: NEOPLASMS (CONTINUED) 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

tTHYMU S

CARCINOMA,NO S

HEPATOCELi.ULA R CARCINOMA , BETAS'!'

 (48) (45)

 1

 1

 (2%) 

 (255) 

 (28 ) 

CIRCULATOR Y SYSTE M 

iiONE 

DIGESTIVE SYSTEM 

KLIVE B

NEOPLASTIC NODUL E

HEPATOCELnULA R CARCINOM A

H EM ANGIOSiiRCOMA , MET ASTATIC

 (49 )

 1 (2%) 

 (50)

 1 (2%) 

 (50) 

1 (2%) 

*CECUfi

FIEROSARCoHA

 (49) (46) (48) 

1 (2%) 

URINAR Y SYSTE.1 

#KIDNE Y

MIXE D TUHvjR , BENIG N

 (49 ) (50) (50) 

1 (2?>) 

KURINAR Y BLAJDE R

TRANSITIO.iAL-CEL L PAPILLOM A

 (48) (42)

 1 (2*) 

 (45 ) 

ENDOCRIN E SYSTE M 

tPITUITARY (48) (50) (46) 

CHROMOPHOdE AD3NOMA 5 (1055) 10 (20%) 7 (15S) 

*ADEENAL (49 ) (49) (50) 

PHEOCHROHuCYTOM A 7 (14S) 9 (18%) 14 (28%) 

• THYROI D (49) (49) (50) 

FOLLICULAh-CEL L ADENOM A 1 (2%) 

FOLLICQLAi-J-CELL CARCINOM A 1 (255) 1 (2%) 1 (2-7.) 

C-CELL ADENOM A 3 (6%) 

C-CELL CAriCINOM A 4 (8%) 1 (2%) 1 <2X) 

ffPANCSEAIIC ISLETS (50) (50) 

* NUMBE R OF ANIMALS KITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUHBE3 OF ANIMALS NECROPSIES
 
TABLE A1. MALE RATS: NEOPLASMS (CONTINUED) 

MATCHED 

LOW DOSE HIGH DOSE CONTROL 

ISLET-CELL CARCINOM A 1 (2X) 

REPRODUCTIVE SYSTEM
 

*MAMMARY GLAsID (49) (50) (50) 

FIBHOADENOMA 1 (2%) 1 (2%) 3 (635) 

*PREPOTIAL GLAND (49) (50) (50) 

CARCINOMA, NOS 2 (4S) 5 (10%) 6 (12%) 

tTESTIS (49) (49) (50) 

INTERSTITiAL-CELL TOH08 44 (90%) 46 (94%) 41 (82S) 

INTERSTITIAL-CELL TUMOR, MALIGN A 1 (2X) 

*£PIDIDYMIS (49) (50) (50) 

INTERSTITiAL-CELL TUMOR , INVASI V 1 (2%) 

NERVOUS SYSTErf
 

#BRAI N (49) (50) (50) 

ASTROCYTOdA 1 (2%) 

SPECIAL SENSE ORGAN S 

*ZYMBAL' S GLAN D (49) (50) (50) 

SQUAHOU S c-ELL CARCINOM A 2 (4%) 

rtUSCULOSKELETA L SYSTEM 

*BONE (49 ) (50) (50)

 

OSTEOSARCUMA 1 (2%) 

*SKELETA L MUjCL E (49 ) (50) (50) 

OSTEOSARCOflA , INVASIV E 1 (2% ) 

BODY CAVITIE S 

TUNICA VAGIiiALI S (49) (50) (50) 

* NUMBER OF AuIJULS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMBER OF AdlHALS NECROPSIED
 

43 
TABLE A1. MALE RATS: NEOPLASMS (CONTINUED) 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

A IL 01KER SYSTEM S 

*MULTIPL E OEoAN S (49) (50) (50) 

MESOTHELIUMA, N05 2 (455) 

JlESOTHELljrtA, MALIGNAN T 1 (2%)

 

ANIMA L DISPOSITION SUMMAR Y 

ANIMAL S INITIALL Y I N STUD Y 50 50 50 

NATURA L DiiATHd 18 11 10 

MORIBUN D SACRIFICE 1 2 4 

SCHEDULED SACBIFICE 

ACCIDENTALLY KILLED 

TERMINAL SACRIFICE 31 37 36 

ANIMAL MISSING 

INCLUDES AUIOLYZED ANIMALS
 

TUMOR SUHMARY
 

TOTAL ANIMALS KITH PRIMARY TUMORS* 47 50 49
 

TOTAL PRIdARY TUMORS 90 106 100
 

TOTAL ANIMALS WITH BENIGN TUMORS 46 47 47
 

TOTAL BENIGN TUMORS' 59 80 77
 

TOTAL ANIMALS WITH MALIGNANT TUMORS 24 23 18
 

TOTAL MALIGNANT TUMORS 28 26 22
 

TOTAL ANIMAL S WIT H SECONDAR Y TUMORS * 3 1 1 

TOTAL SECONDAR Y TUMORS 3 2 1 

TOTAL ANIMAL S WITH TUMORS UNCERTAIN ­

BENIG N OR MALIGNAN T 3 1 

TOTAL UNCERTAI N TUMORS 3 1 

TOTAL ANIMAL S WIT H TUMORS UNCERTAIN ­

-PBIMAR Y OR i-iETASTATIC 

TOTAL UNCdHTAIN TUMORS 

* PRIMAR Y TUHOBS: ALL TUMOflS EXCEPT SECONDARY TUMORS 

* SECONDAR Y TUMORS : METASTATIC TUHORS OH TUMORS INVASIV E INTO AN ADJACENT ORGAN 

44 
TABLE A2. 

SUMMARY OF THE INCIDENCE OF NEOPLASMS IN FEMALE RATS 

ADMINISTERED TITANIUM DIOXIDE IN THE DIET 

ANIMALS INITIALLY IN STUDY
 

ANIMALS NSCHOPSIED
 

ANIMALS EXAMINED HISTOPATHOLOGICALLY
 

INTtGUMENTAKY SYSTEM
 

*SKIN
 

SQUAMOUS CELL CARCINOMA
 

*5UBCUT TISSUE
 

SQUAHOUS CELL CARCINOMA
 

FIBROMA
 

RESPIRATORY SYSTEM
 

*LUNG 

SQUAMOU S CELL CARCINOMA , METASTA 

ALVEOLAR/ufiONCHIOLAR ADENOM A 

ALVEOLAR/iiRONCHIOLAR CARCINOM A 

HEMATOPOIETIC SYSTEM
 

*HULTIPLS ORGAN S

MALIG.LYMPHOMA , HISTIOCfTIC TYPE 

GRANULOCYTIC LEUKEMI A 

MONOCYTIC LEUKEMI A

tCJSEVICAL LYdPH NODE

SQUAMOU S CELL CARCINOMA ,

CIRCULATORY SYSTEM
 

NONE
 

DIGESTIVE SYSTEM
 

tLIVER
 

_ NEOPLASTIC NODULE,
 

 METASTA 

MATCHED
 

CONTROL
 

50
 

50
 

50
 

(50)
 

1 12%)
 

(50)
 

1 (2%)


1 (2%)
 

(50) 

2 (4X) 

1 (2%) 

 (50) 

 10 (2095) 

 (50) 

(50)
 

LOW DOSE HIGH DOSE
 

50	 50
 

50	 49
 

50	 49
 

(50)	 (49)
 

3 (6X)
 

(50)	 (19)
 

1 (2%)
 

1 (2%)
 

(50) (49) 

1 (2X) 

1 (2X) 1 (2%) 

(50) (49)
 

2 (48)
 

1 (2X) 1
 

10 (20X) 11 (2255)
 

(50)	 (49)
 

2 <4S)
 

(49)
 

I	 NUMBER OF AiilMALS HITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMBED OF ANIMALS NECROPSIED
 

45
 
TABLE A2. FEMALE RATS: NEOPLASMS (CONTINUED) 

MATCHED 

CONTROL LOW DOSE 

ffSTCMACH (50) (50) 

SQUAMOUS CELL PAPILLOMA 

URINAR Y SYSTSd 

NON E 

ENDOCRIN E SYSlEM 

•PITUITARY (U8) (1*7) 

CARCINOMA , NOS 3 (6%) 

CHPOMOPHOjE ADENOM A 28 (58%) 26 (55%) 

CHROMOPHOo E CARCINOM A 

• ADBENA L (50) (49) 

CORTICAL *DENOMA 2 (4%) 

FHEOCHROMOCYTOM A 1 (2%) 

IFTHYROI D (48) (47)

 

FOLLICULAH-CELL ADENOM A 2 (4%)

 

C-CELL ADENOM A 

C-CSLL CAKCINOMA 1 (2%) 

*PANCREATIC ISLETS (50) (50) 

ISLET-CELi, ADENOM A 1 (2%) 

8EPRODUCTIVE SYSTEM 

*MAMMAR Y GLAtMD (50) (50) 

ADENOMA , ufU S 

ADBNOCARCiNOBA, NOS 1 (2«) 2 (4&) 

CYSTADENOilA , NOS 1 (2%) 

FIBROADEMOM A 20 (UOSS) 14 (28%) 

*PREPUTIAL GLAN D (50) (50) 

CARCINOKA.NO S 2 (4%) 2 (4%) 

ADENOMA , fciO S 1 (255) 

tUTERU S (50) (50) 

CARCINOMA , NOS 

FIdROMA 1 12%) 

* NUMBE R OF ANIMALS WITH TISSUE EXAMINE D MICROSCOPICALLY 

* NUKBii K OF ANIMAL S NECROPSIE D 

HIGH DOSE 

(48) 

1 (2%) 

(47) 

3 (6X) 

31 (66%) 

1 (2%) 

(19) 

1 (2X) 

(44 ) 

2 (5X) 

4 (9%) 

(490 

(49) 

1 (27.) 

2 (4%) 

19 (39%) 

(49) 

3 (b%) 

(49) 

1 (251) 

46 
TABLE A2. FEMALE RATS: NEOPLASMS (CONTINUED) 

ENDOMETRI^L STROMAL POLYP


tUTERUS/ENDOnETRIUM


SARCOMA, SOS


ENDOMETRIaL STEOMAL POLYP


#OVARY


FIBROMA


SEMINOMA/uYSGERMINOMA


NERVOUS SYSTEM
 

*3fiAIN

CARCINOMA , NGS, MBTASTATIC

SQUAMOU S CEL L CARCINOMA . METAST A

CHROHOPH00E CARCINOMA , MET AST ATI

GLIOMA , NOS

ASTROCYTOhA


SPECIAL SENSE ORGANS
 

*HAHDERIAN GLAND


SQUAMOUS CELL CARCINOMA,


*EAB CANAL


SQUAMOUS CELL CARCINOMA


tfUSCULOSKELETAL SYSTEM
 

*SKELETAL MUSCLE


SARCOMA , iiOS

ECD Y CAVITIE S 

NON E 

A LL OTHER SYSi'EM S 

 METASTA


MATCHED CONTROL LOW DOSE HIGH DOSE 

6 (12%) 15 (30%) 10 (20!J) 

 (50) (50) (49) 

1 (27.) 

1 (2%) 

 (49) (49) (49) 

1 (2%) 

1 (2%) 

 (48) (48) (49 ) 

2 (48) 2 (47.) 

1 (2%) 

1 (2%) 

1 (2%) 

1 (2X) 

 (50) (50) (49) 

1 (2%) 

 (50) (50) (49) 

1 (2%) 

 (50) (50) (49) 

1 (2%) 

* NUMBER OF AuIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMBER OF AwIKALS N2C80PSIED
 

47 
TABLE A2. FEMALE RATS: NEOPLASMS (CONTINUED) 

MATCHED
 

CONTROL LOW DOSE HIGH DOSE
 

SNIMAL DISPOSITION SUMMARY
 

ANIMALS INITIALLY IN STUDY
 

NATURA L DEATHS
 

MORIBUND SACRIFICE
 

SCHEDULED SACRIFICE
 

ACCIDENTALLY KILLED
 

TERMINAL SACRIFICE
 

ANIMA L MIoSING
 

dS INCLUDES AUiOLYZED ANIMALS
 

TUMO R SUMMAR Y
 

TOTAL ANIMALS KITH PRIMARY TUMORS*
 

TOTAL PRIMARY TUMORS
 

TOTAL ANIMAL S WITH BENIGN TUMORS
 

TOTAL BENiGN TUMORS
 

TOTAL ANIMALS WITH MALIGNANT TUMORS
 

TOTAL MALIGNANT TUMORS
 

TOTAL ANIMALS WITH SECONDARY TUMORS*


TOTAL SECONDARY TUMORS


TOTAL ANIMALS WITH TUMORS UNCERTAINBENIGN OH MdLIGNANT


TOTAL UNCERTAIN TUMORS


TOTAL ANIMALS WITH TUMORS UNCERTAINPRIMAR Y OR tIETASTATIC
 

TOTAL UNCERTAIN TUMORS
 

50 50 50 

11 12 14 

3 2 2 

36 36 34 

41 43 46 

83 86 96 

38 37 41 

62 63 66 

19 20 24 

20 23 30 

1 3 5 

1 3 6 

1 

1 

* PRIMARY TUMORS: ALL TUMORS EXCEPT SECONDARY TUMORS
 

* SECONDARY TUMORS: METASTATIC TUMOKS OR TUMORS INVASIVE INTO AN ADJACENT ORGAN
 

48
 
APPENDIX B
 

SUMMARY OF THE INCIDENCE OF NEOPLASMS IN
 

MICE ADMINISTERED TITANIUM DIOXIDE IN THE DIET
 

49
 
50

 
TABLE B1.

 

SUMMARY OF THE INCIDENCE OF NEOPLASMS IN MALE MICE 

ADMINISTERED TITANIUM DIOXIDE IN THE DIET 

.«————— TM--"- ­» 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

ANIMAL S INITIALL Y I N STUD Y 50 50 50 

ANIMAL S NECROfSIE D 47 49 49 

ANIMAL S EXAMINE D HI STOP ATHOLOGIC ALL Y 47 49 49 

INTEGUMENTAR Y SYSTEM
 

*SKI N .(«7) (49) (49) 

FIBROM A 1 (2«) 

*SUBCUT TISSU E (47) (49) (49 ) 

SEBACEOUS ADENOM A 1 (2%) 

FIBROM A 4 (955) 3 (6X) 1 (2%) 

FIlifiOSARCXlMA 8 (1735) 8 (16S) 4 (835) 

HEMANGIOSaRCGM A 1 (2%) 

RESPIRATORY SYSTEM
 

#LUN G (46) (49) (49) 

HEPATOCELjuULA R CARCINOMA , METAS T 2 (4% ) 1 (235) 

ALVEOLAK/oRONCHIOLA R ADENOM A 5 (1U) 2 (435) 5 (10X) 

ALVEOLAR/jRONCHIOLA R CARCINOM A 1 (2%) 1 (235) 

HEMAIOPOI2TIC SYSTEM
 

"KULTIP L E ORGAN S (47) (49) (49 ) 

MALI G .LYflfHOM A , LYMPHOCYTI C TYP E 4 (935) 2 (4X) 

flALIG .LYKr>HOB A r HISTIOCYTIC TYP E 1 (2%) 3 (635) 5 (103) 

GRANULOCYi'I C L EUKEMI A 2 (4%) 

»KE3FN T E H IC i.. NOD E (47) (48) (48 ) 

HEMA N GIOMii 2 (435) 

H EM A N Gios«ificoa 1 (2X) 

HALI G . LYHrHOM Ai HISTIOCYTIC TYP E 1 (2X) 

CIRCULATOR Y SYSTEM 

(4b) (49) (49 ) 

HEMA|i2I2 S 

a NUMBE R OF ANIMAL S WITH TISSUE EXAMINED MICROSCOPICALL Y
 

* NUMBE R OF AnIMAL S NECROPSIED
 

51
 
TABLE B1. MALE MICE: NEOPLASMS (CONTINUED) 

DIGESTIV E SYSTE M 

*INTESTINAL TRACT

CARCINOMA,NO S

»LIVER


HEPATOCELi,ULAH CARCINOMA


HEMANGIOSiRCOMA


*SMALL INTESTINE


CARCINOMA,NOS


URINARY SYSTEM
 

*UBETHR A

TRANSITIONAL-CEL L CARCINOM A

ENDOCRINE SYSiEM
 

tADRENA L

FHEOCHROMOCYTOM A

frTHYROID

FOLLICULA^-CELL

REPRODUCTIV E SYSTE M 

STESTIS


HEMANGIOMA


NZBVOUS SYSTE.-,
 

NONE
 

SPECIAL SENSr, ORGAN S
 

*EYE/LACRIMAi, GLAND


ADENOMA, ;iOS


 ADENCM A

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

 (47) (49) (49 ) 

1 (2%) 

 (47) (47) (49) 

8 (17%) 9 (19S) 14 (29%) 

1 (255) 

 (47) (49) (49) 

1 (2%) 

 (47) (49) (49) 

1 (2%) 

 (46) (49) (48) 

1 (28) 2 (4%) 

 (43) (45) (45) 

1 (2») 

 (47) (49) ('t8) 

2 (4X) 

 (47) (49) (49) 

1 (2%) 1 (2%) 

MUSCULOSKELHT.^L SYSTEM
 

NONE
 

» NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUME23 OF ANIMAL S NECROPSIED
 

52
 
TABLE 81. MALE MICE: NEOPLASMS (CONTINUED) 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

ECD Y CAVITIE S 

NON E 

ALL OTHER SYSTEMS
 

*MULTIPLE ORGANS (47) (49) (49)
 

HESOTHELI-MA, NOS 1 (2%)
 

fNIMAL DISPOSITION SUMMARY
 

ANIMALS INITIALLY IN STUDY 50 50 50
 

NATURAL DEATHS 17 10 10
 

MORIBUND SACRIFICE
 

SCHEDULED SACRIFICE­ ACCIDENTALLY KILLED 1
 

TERMINAL SACRIFICE 32 40 40
 

ANIMAL HISSING
 

* INCLUDES AUIOLYZED ANIMALS
 

TUMOR SUMMAR Y
 

TOTAL ANIMALS WITH PRIMARY TUMCHS* 29 25 28
 

TOTAL PRIiiAHY TUMORS 36 37 38
 

TOTAL ANIMALS WITH BENIGN TUMORS 10 8 11
 

TOTAL BENiGN TUMORS 10 10 12
 

TOTAL ANIMALS WITH MALIGNANT TUBOBS 22 22 23
 

TOTAL MALIGNANT TUMORS 25 27 26
 

TOTAL ANIMALS WITH SECONDABY TUMOBSf 2 1
 

TOTAL SEOJNDA8Y TUMORS 2 1
 

TOTAL ANIHA.LS IITH TUBOES UNCERTAINBENIGN OR MALIGNAN T 1

 

TOTAL UNCERTAI N TUMORS 1 

TOTAL ANIBALS WITH TUMORS UNCERTAIN-

PfilMARY OH SETASTATIC 

TOTAL UNCERTAI N TUMORS 

* PRIMAR Y TUMORS: ALL TUMOBS EXCEPT SECONDARY TUBORS 

t SECONDABY TUMORS : BET&STATIC TOBOHS OB TUMOBS INVASIVE IMTO AN ADJACENT ORGAS 

53 
TABLE B2.

 

SUMMARY OF THE INCIDENCE OF NEOPLASMS IN FEMALE MICE 

ADMINISTERED TITANIUM DIOXIDE IN THE DIET

 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

ANIMAL S INITIALL Y I N SIUD Y 50 50 50 

ANIMAL S HISSIu G 1 

iNIHALS NEC80i?SI2D 49 50 50 

JNIMAL S EXAMIai D HISTOPATHOLOGICALL Y 49 50 50 

INTEGUMENTARY SYSTEM
 

*SUBCUT TISSUE (49) (50) (50) 

TRICHOEPIiHELIOMA 1 (2%) 

FIBROSARCdMA 2 (4%) 

5ESPIEATOR Y SYSTEM 

#LUN G (49 ) (50) (50) 

ADENGCARCiNOHA , NOS, MEIASTATIC 1 (2% ) 

ALVEOLAR/riRONCHIOLA R ADENOM A 1 (2X) 3 (6X) 

ALVEOLAR/jRONCHIOLAB CARCINOM A 1 (2%) 1 <2X) 1 (2%) 

FIBROSARCdMA , METASTATIC 1 (2%) 

LEIOMYOSAttCOMA , METASTATIC 1 (2%) 

HEMATOPOIETIC SYSTEM 

*MULTIPLE ORGAN S (49) (50) (50) 

MALIG.LYMPHOMA , LYMPHOCYTIC TYPE 6 (12») 4 (8») 7 (1455) 

MALIG.LYMPHOMA , HISTIOCYTIC TYPE 12 (24%) 7 (143t) 4 (8X) 

MALIGNAN T LYMPHOMA , MIXBD TYPE 2 (4%) 

GRANULOCYIIC LEUKEMI A 2 (4%) 

#SPLEEN (49) (50) (50) 

HEMANGIOSABCOM A 1 (28) 

HALIG.LYMPHOBA , HISTIOCYTIC TYPE 1 (2%) 

•CERVICAL	 LYuPH NODE (48) (47) (47)
 

HEMANGIOSAECOMA 1 (2%)
 

*THYMUS (23) (27) (34)
 

FIBROSARCUHAj_META STATIC
 

« NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMBER OF ANIMALS NECROPSIED
 

54
 
TABLE B2. FEMALE MICE: NEOPLASMS (CONTINUED) 

MATCHED 

CONTROL LOW DOSE 

CIRCULATOR Y Si'STtfl 

tHEAH T (49 ) (50)

 

HEMANGIOMf t 

CiGESTIV E SYSIE K 

SLIVER (49) (50)

 

HEPATOCEi^ULA S CARCINOM A 1 (255) 3 (6%) 

• PANCREA S (49) (50)

 

FIBROSARCOMA , HETASTATIC 1 (255) 

*STOBACH (48) (50)

 

LEIOBYOSAaCOM A 1 (2X)

 

*LARG E INTESTINE (48) (50)

 

LEIOMYOSAHCOMA , BETASTATIC 1 (2%)

 

UBINAE Y SYSTEd 

#KIDNE Y (49) (50)

 

TUBULAR-CiiLL ADENOCARCI NOB A 1 (235) 

LEIOMYOSAaCOBA , METASTATIC 1 (2X)

 

&URINAR Y BLADDER (47) (45)

 

LEIOMYOSARCOMA , METASTATIC 1 (2%)

 

ENDOCRINE SYSi'EB 

#PITOITARY (33) (tO)

 

CHBOMOPHOoE ADENOM A 3 (9») 4 (10«)

 

#THYROID (43) (41)

 

FOLLICULAH-CELL ADENOM A 3 (7S)

 

C-CELL ADENOM A 

REPRODUCTIV E SYSTEM 

*MAMBARY GLAN D (49) (50) 

ADJENOCAHCINOMA . NOS _ 1 12$L 1.128) , 

t NUMBER OF ANIBALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUBBER OF AtUBALS NECROPSIED
 

HIGH DOSE 

(50 ) 

1 (2%) 

(50) 

3 (6%) 

(50) 

(49) 

(49 ) 

(50) 

(45) 

(33) 

2 (6%) 

(44) 

1 (28) 

(50) 

3 16%} 

55
 
TABLE B2. FEMALE MICE: NEOPLASMS (CONTINUED) 

#UTERUS


LEIOHYOSArfCOMA, METASTATIC


ENDOMETEIAL SIROKAL POLYP


HEMANGIOSaRCGMA


tOVARY


PAPILLARY CYSTADENCMA, NOS


TERATOMA, NOS


SEHVG'JS SYSTEM
 

NONE
 

-SPECIAL SENSE ORGANS
 

*EYE/LACRMA^ GLAND


CABCINCMA,NOS


ADENOMA,


MUSCULOSKEL^TAL SYSTEM
 

NONE
 

BODY CAVITIES
 

*ABDOhINAL CnVITY


HEHANGIOSAECOMA


+BESENTES Y

LEIOHYOSfiSCOMA , METASTATIC

A L L OTHEB 5YS1EMS 

NON E 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

 (49) (49) (49) 

1 (2%) 

1 (2%) 

1 (2%) 

 (47) (47) (47) 

1 (2%) 

1 (2%) 

 (49) (50) (50) 

1 (2%) 

 flOS 1 (2«) 

 (49) (50) (50) 

1 (2%) 

 (49) (50) (50) 

1 (2%) 

* NUMBER OF ArilMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMBZR OF AuIBALS NSCBOPSIED
 

56
 
TABLE B2. FEMALE MICE: NEOPLASMS (CONTINUED) 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

JNIMA L DISPOSITION SUMMAR Y 

ANIMAL S INITIALL Y I N STUD Y 50 50 50
 

NATURA L CfiATHS 1 1 16
 

MORIBUN D SACRIFICE 1
 

SCHEDULE D SACRIFICE 

ACCIDENTALL Y KILLE D 

TERMINAL SACRIFICE 45 39 33
 

ANIMAL MISSING 1
 

a INCLUDES AUiOLYZED ANIMALS
 

TCM08 SUMMAR Y
 

TOTAL ANIMALS WITH PRIMABY TUMORS* 30 24 26
 

TOTAL PRIMARY TUMORS 34 26 32
 

TOTAL ANIMALS WITH BENIGN TUMORS 6 6 9
 

TOTAL EENiGN TUMORS 7 6 9
 

TOTAL ANIMALS KITH MALIGNANT TUMORS 26 19 18
 

TOTAL MALIGNANT TUMORS 27 20 22
 

TOTAL ANIMALS WITH SECONDARY TUMORS* 1 1 1
 

TOTAL SECONDARY TUMORS 6 3 1
 

TOTAL ANIMALS WITH TUMOPS UNCERTAINBENIGN OR fiALIGSANT 1
 

TOTAL UNCERTAIN TUMORS 1
 

TOTAL ANIMALS WITH TUMORS UNCEBTAIN-


EtlMARY OR ,'i H.IASTATIC
 

TOTAL UNCERTAIN TUMOBS
 

* PRIMARY lUMoRS: ALL TUMORS EXC2PT SECONDARY TUMORS
 

* SECONDARY 1'UMORS: MSTASTATIC TUMORS 03 TUMORS INVASIVE INTO AN ADJACENT ORGAN
 

57
 
58

 
APPENDIX C
 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS
 

IN RATS ADMINISTERED TITANIUM DIOXIDE IN THE DIET
 

59
 
60

 
TABLE C1.

 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS IN MALE RATS 

ADMINISTERED TITANIUM DIOXIDE IN THE DIET 

MATCHED 

CONTROL LOW DOSE 

ANIMAL S INITIALLY IN STUDY 50 50 

ANIMAL S NECPOf SIED 49 50 

ANIMAL S EXAMINE D HISr .^PATHOLOGICALLY 4 9 50 

INTEGUMENTARY SYSTEM
 

*SKIN (49) (50)
 

EPIDERMAL INCLUSION CYST 1 (2%)
 

METAPLASI*, SQUAMOOS 1 (2%)
 

*SUBCUT TISSUE (49) (50)
 EPIDERMAL INCLUSION CYST 1 (2X)
 

INFLAMMATION, DIFFUSE 1 (2X)
 

GRANULOMA, FOREIGN BODY
 

RESPIRATORY Si STEM
 

*LUNG (49) (50) 

CONGESTION, NOS 6 (12X) 

HEMORRHAGE S 5 (10%) 

INFLAMMATION, SUPPURATIVE 

PNEUMONIA , CHRONIC MURIN E 5 (10X) 7 (14X) 

HEMATOPOIETIC SYSTEM
 

tBONE MARROW (48) (50)
 

HYPOPLASIA, HEM&TOPOIETIC 2 (4X)
 

*SPIEEN (49) (50)
 

CONGESTION, NOS 1 (2%)
 

FIBROSIS 1 (2X)
 

INFARCT, NOS 1 (2%)
 

PIGHENTATION, NOS 1 (2X)
 

HYPERPLAS14, STBOHAL
 

HEMATOPOIjiSIS 1 (2X)
 

*LYHPH NODE (49) (50)
 

# NUHBE8 OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMBER OF ANIMALS NECROPSIED
 

HIGH DOSE 

50 

50 

50 

(50)
 

(50)
 

1 (2%)
 

(49) 

13 (27S) 

6 (12X) 

1 (2X> 

4 (8%) 

(50)
 

(50)
 

1 (2X)
 

2 (H%)
 

1 (2X)
 

1 (2X)
 

1 (2%)
 

4 (8X)
 

(50)
 

1T (2X)
 

61
 
TABLE C1.MALE RATS: NONNEOPLASTIC LESIONS (CONTINUED) 

HCEHVICAI LYaPH NODE
 

HYPERPLASIA, LYHPHOID
 

fBRONCHIAL LiAPH NODS
 

THROMBOSIS, NOS
 

ftWESfiNTERIC i,. NODE
 

LYMPHANGI&CTASIS
 

THROMBOSIS, NOS
 

KTHYMUS
 

EMBRYONAL REST
 

THROMBOSIS, NOS
 

HYPERPLASXA, NOS
 

CIRCULATORY SYSTEM
 

•HEART
 

THROMBOSIS, NOS
 

THROMBUS, ORGANIZED
 

INFLAMMATION, CHRONIC
 

FIBHOSIS
 

DEGENERATION, NOS
 

•MYOCARDIUM
 

INFLAMMATION, NOS
 

INFLAMMATION, CHRONIC
 

DEGENERATION, NOS
 

*AORTA
 

INFLAMMATION, NOS
 

DIGESTIVE SYSTEM
 

ISALIVABY GLAND
 

INFLAMMATION, CHRONIC
 

ILIVER
 

CONGESTION, NOS
 

PELIOSIS HEPATIS
 

DEGENERATION, L IPO ID
 

JiECBQSIS^ SQS
 

MATCHED
 

CONTROL
 

(49)
 

(49)
 

(49)
 

(48)
 

(49)
 

1 (235)
 

1 (2X)
 

1 (2X)
 

(49)
 

1 (2JS)
 

1 (2%)
 

1 (2*)
 

(49)
 

(47)
 

(49)
 

1 (2»)
 

LOW DOSE
 

(50)
 

(50)
 

(50)
 

(45)
 

1 (2X)
 

(50)
 

1 (2X)
 

11 (22X)
 

8 (16X)
 

150)
 

1 (2%)
 

(50)
 

(50)
 

1 (2X)
 

(50)
 

1 (2%)
 

HIGH DOSE
 

(50)
 

1 (2%)
 

(50)
 

1 (2»)
 

(50)
 

1 (2%)
 

1 (256)
 

(28)
 

1 (4»)
 

1 (455)
 

(49)
 

1 (2X)
 

12 (24%)
 

(49)
 

(50)
 

1 (2X)
 

(50)
 

(50)
 

1 (2X)
 

1 (2%)
 

2 (t*l
 

I NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 * NUMBER OP AalMALS NECROPSIED
 

62
 
TABLE C1. MALE RATS: NONNEOPLASTIC LESIONS (CONTINUED) 

MATCHED 

CONTROL LOW DOSE 

NECBGSIS, F :AL 

INFAflCT, NO S 

METAMORPHOSI S FATT Y 

FOCAL CELLULA R CHANG E 

1 (2%) 

1 <2X) 

3 (6X) 

KLIVER/CENTR.L.LOBULAR 

NECROSIS , NOS 

(49) 

1 (2%) 

(50) 

1 (2% ) 

*BILE DUCT 

FIBROSIS 

HYPERPLASiA NOS 

(19) (50) 

1

21

 (2%) 

 (42%) 

•PANCREA S 

INFLAMMATION , CHRONI C

PERIARTERj-TI S 

PIGMENTATION, NOS 

ATROPHY , NO S 

HYPERPLASiA , FOCAL 

 FOCAL 

(49) 

2

1

 (4%) 

 (2%) 

(50) 

1

5

1

1

1

 (2%) 

 (10%) 

 (2X) 

(2%) 

 (2%) 

*PANCREATI C uUCT 

HYPERPLASiA , NO S 

(49 ) (50) 

»PANCREATI C

ATROPHY ,

 aCINU S 

 NOS 

C»9) (50) 

*STOKAC H 

ULCER , FOCAL 

INFLAMMATION , CHRONI C 

HYPEBKERAI'OJI S 

ACANTHOSI o 

(49) (50) 

5 (10%) 

2 (4») 

2 (4%) 

*3MALL INT r ij.IN E 

ULCER , FOCA L 

(49) (50) 

1 (2%) 

*ILEU M 

MECKEL S DiVSBTICULU M 

(49) (50) 

INFLAMMATION , CHRONIC 

ffCOLON 

PAHASITIS a 

(49 ) 

3 (6%) 

(46) 

13 (283) 

UBINAK Y SYSTEn 

tKIDNE Y (49) (50) 

HYCBONBPH^OSI S 

» NUMBE R OF AalMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMBE R OF AuInALS NSCPOPSIED
 

HIGH DOSE 

1 (2*) 

3 (6%) 

1 (2%) 

(50) 

(50) 

27 (54?) 

(50) 

3 (6«) 

(50) 

1 (2%) 

(50) 

2 (4%) 

(50) 

4 (8%) 

1 (2%) 

(47) 

(47 ) 

1 (2%) 

1 (2%) 

(48 ) 

6 (137.) 

(50) 

. _ 1 123L _ 

63
 
TABLE C1.MALE RATS: NONNEOPLASTIC LESIONS (CONTINUED) 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

CYST, NOS 2 (4% ) 

CONGESTION, NOS 1 (2%) 

PYELONEPHRITIS , NOS 1 (2%) 

INFLAMMATION , CHRONIC 29 (5958) 45 (90%) 43 (86S) 

PERIARTERITIS 1 (2%) 

AMYLOIDOSIS 1 (2%) 

PIGMENTATION , NOS 1 (2%) 

ENDOCRIN E SYSIEM 

((PITUITAR Y (48) (50) (46) 

CYST, NOS 1 [2%) 

HEMORRHAG E 1 (2%) 

ANGIECTASI S 1 (2%) 

KADRENA L (49) (49) (50) 

ANGIECTASIS 1 (2%) 

*AD8ENA L CORiE X (49) (49) (50)

 

DEGENERATION , NOS 1 (2%) 

fADRENA L MEDULL A (49) (49) (50 ) 

HYPERPLASiA , NOS 1 (2X) 

fTKYROI D (49) (49) (50) 

CYSTIC FOLLICLES 1 (2%) 

HYPERPLASiA , C-CELL 1 (2%) 

HYPERPLASIA , FOLUCULAR-CEL L 1 (2%) 

»PANCREATI C J.SLETS (49) (50) (50) 

HYPERPLASIA , NOS 1 (2% ) 

REPRODUCTIV E oYSTE M 

*MAMMAR Y GLAul D (49) (50) (50) 

GALACTOCEL E 2 (4% ) 1 (2«) 

*PHEPUTIA L Gi-AND (49 ) (50) (50) 

EPIDERMA L INCLUSIO N CYST 2 (4%) 

ABSCESS, NO S 1 (2%) 

INFLAMMATION , CHRONI C 1 (2%) 

HYPERPLASiA , NO S 1 (2%) 

KPROSTAT E £47 ) (43) (45 )

 

INFLAMMATION ^ NOS 1 ±2%}_ 

* NUMBER OF AiJIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMBER OF AwIMALS NECROPSIED
 

64
 
TABLE C1. MALE RATS: NONNEOPLASTIC LESIONS (CONTINUED) 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

INFLAMMATION , SUPPURATIV E 1 (2%) 6 (18%) 

INFLAMMATION , CHRONI C 1 (2%) 

*S£hINA L VESICL2 (50) (50) 

ATROPHY , NOS 6 (12%) 10 (20%) 

»TESIIS (49) (50) 

ATROPHY , NOS 3 (6%) 5 (10X) 7 (14%) 

HYPERPLASiA , INTERSTITIA L CEL L 3 (6%) 4 (B%) 

*2,PIDIDYi1IS (19) (50) (50)
 

NECROSIS, FAT 2 (4%)
 

NERVOUS SYSTEM
 

#BRAIN (49) (50) (50) 

HYDROCEPHaLUS , NOS 1 (2%) 

ABSCESS, SOS 1 (2%) 

SPECIAL SENSE ORGAN S 

ifON E 

MUSCULOSKELETAL SYSTEM
 

NONE
 

BODY CAVITIES
 

*ABDOMINAL CAVITY (49) (50) (50)
 

NECROSIS, FAT 4 (8%) 2 (US)
 

*PEEITONEAL CAVITY (<»9) (50) (50)
 

NECEOSIS, FAT 3 (655)
 

*PERICARDIUK (49) (50) (50)
 

INFLABHATxON, NOS 1 (2%)
 

*MESENTERY (49) (50) (50)
 

PERIARTEEiTIS 1 (2%) 1 (2%)
 

NECEOSI^. FAT _,..2 J[4%1
 

# NUBBER OF ANIMALS WITH TISSUE EXAHlNED HICHOSCOPICALLY
 

* NUMBER OF ANIMALS NECROPSIED
 

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

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

A LL OTHER SYSI'EMS 

DIAPHRAG M 

HERNIA , NOS 1 

SPECIAL MORPHOLOG Y SUMMAR Y 

AUTO/NECRUPSY/HISTO PERT 1 

AUTOLYSIS/NO NECROPSY 1 

* NUMBE R OF AiUMALS WITH TISSUE EXAMINE D MICROSCOPICALLY 

* NUMBE R OF AwIMAL S NECROPSIED 

66 
TABLE C2. 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS IN FEMALE RATS 

ADMINISTERED TITANIUM DIOXIDE IN THE DIET 

MATCHED
 

CONTROL LOW DOSE HIGH DOSE
 

ANIMALS INITIALLY IN STUDY 50 50 ' 50
 

ANIMALS NECROPSIED 50 50 49
 

ANIMALS EXAMINED HISTOPATHOLOGICALLY 50 50 49
 

INTEGUMENTARY SYSTEM
 

*SKIN (50) (50) (49)
 

ABSCESS, HOS . 1 (2%)
 

*SUBCUT TISSUE (50) (50) (49)
 

NECROSIS, FAT 1 (2%)
 

RESPIRATORY SYSTEM
 

ffLUNG (50) (50) (49) 

CONGESTION , NOS 12 (242) 10 (20%) 

HEMORRHAG i 1 (2S) 8 (16%) 9 (18%) 

PNEUMONIA , CHRONI C PIUEIN E 3 (6%) 3 (6%) 1 (2%) 

INFLAMMATION , GRANULCMATOU S 1 (2%) 

EPITHELIAi,IZATIO N 1 (2%) 

HEMATOPOIETI C SYSTE M 

fSPLEE N (50) (50) (48) 

FIBRCSIS 1 (2%) 1 (2X) 

PIGMENTATION , NO S 2 (4%) 

AT30PHY , i40S 4 (8») 1 (2%) 

HEMATOPOI^SIS 2 (4%) 1 (2%) 

((CERVICA L LYdP H NOD E (50) (50) (49) 

INFLAMMATION , NOS 3 (6f.) 1 (2%) 

HYPERPLASxA , LYMPHOI D 1 (2X) 

KMESENTERI C L. NOD E (50) (50) (49) 

HEMOHRHAG i 1 (2%) 

INFLASMATiON , NO S 1 (2%) 

»THYHUS (35) (24)
 

CYST^.NOS
 

tf NUMBE R OF A.iIMALS WITH TISSUE ;XAMI MED MICROSCOPICALLY
 

* NUMBER OF ANIMALS NECfiOPSIED
 

67
 
TABLE C2. FEMALE RATS: NONNEOPLASTIC LESIONS (CONTINUED) 

MATCHED
 

CONTROL
 LOW DOSE
 

CONGESTION, NOS	 2 (6%)
 

CIRCULATORY SYSTEM
 

tHEART (50) (50) 

FIBROSIS 10 (20%) 

CALCIFICATION, NOS 1 (2%) 

tMYOCARDIUM (50) (50) 

FIBROSIS 1 (2%) 

DEGENERATION, NOS 1 (2%) 1 (2%) 

DIGESTIVE SYSIEM 

*LIVER (50) (49) 

CONGESTION , NOS 5 (10% ) 

INFLAMMATION , NOS 1 (255) 

INFLAMMATION , FOCAL GRANULOMATO U 1 (2%) 

DEGENERATION , LIPOID 3 (6%) 

METAMORPHOSI S FATTY 2 (435) 

FOCAL CELLULAR CHANG E 3 (6%) 5 (10%) 

ANGIECTASiS 1 (2%) 

tLIVER/CENTRILOBULA R (50) (49)

 

NECSOSIS, NOS 

*BILE DUCT (50) (50) 

FIBROSIS 

HYPEEPLASiA , NO S 14 (28%) 

#PANCREAri C ACINU S (50) (50) 

ATROPHY , iJOS 2 (4%) 

ATROPHY , r'OCAL 

SSTOMAC H (50) (50) 

INFLAMMATION , NO S 1 (2%) 

ULCER , NOa 1 (255) 

ULCER, FOCAL 1 (235) 4 

CALCIFICATION , NOS 1 (2%) 

HYPERPLASiA , BASA L CELL 1 (2%) 

HYPERKERA^OSI S 

ACANIHOSI i 

•GASTRIC SUBttUCOSA (50) (50)
 

EDEMA^NOi 

* NUMBER OF AtilKALS WITH TISSUE EXAMINED MICROSCOPICALLY
 * NUMBER OF ANIMALS NSCROPSIED
 

HIGH DOSE
 

(49 ) 

5 (1035) 

1 (2%) 

(49) 

(49 ) 

2 (4% ) 

3 (6%) 

1 (2%) 

3 (6%) 

(49) 

1 (2%) 

(49 ) 

1 (2%) 

14 (29%) 

1 (2% ) 

3 (635) 

(48 ) 

1 (2%) 

3 (635) 

2 (4%) 

2 (435) 

2 (435) 

(48) 

68
 
TABLE C2. FEMALE RATS: NONNEOPLASTIC LESIONS (CONTINUED) 

MATCHED 

CONTROL LOW DOSE 

#COLC N (50) (50) 

ADHESION , NO S 

PARASIIISi-i 5 (10%) 

*COLONIC SUBI-IUCOSA (50) (50)

 

EDEMA , NOi 

(tCECUM (50) (50) 

HEMORRHAG E 1 (2%) 

*RECTUM (50) (50)

 

ADHESION , NO S 

UEINAE Y SYSTEd 

tKIDNE Y (50) (50) 

MINERALIZATIO N 

CONGESTION, NOS 2 (4«) 

PYELONEPHRITIS , NOS 1 (2%) 

INFLAMMATION , CHRONIC 19 (38%) 24 (46%) 

CALCIFICATION, NOS 1 (2X) 

PIGMENTATION , NOS 1 (2%) 

•KIDNEY/PELVIS (50) (50)

 

INFLAMMATION , NOS 1 (2%)

 

KURINAR Y BLADDER (47) (48) 

HEMORRHAG E 

INFLAMMATION , CHRONIC 1 (2%)

 

HYPERPLASIA , EPITHELIAL 1 (2«).

 

ENDOCRIN E SYSTEM 

•PITUITARY (US) (47) 

CYST, NOS 2 (4%) 2 (4%) 

HYPERPLASIA. CHROMOPHOBE-CELL 

• »ADRENA L (50) (49) 

ANGIECTAS1S 1 (2X) 2. (4%) 

tTHYROI D (48) (47)

HYPERPLASIA , C-CELL 5 nm 

# NUHBER OF ANIMALS HITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUHBER OF ANIMALS NECROPSIED
 

HIGH DOSE 

(49 ) 

1 (23) 

2 (4%) 

(49) 

1 (2%) 

(<*9) 

(49 ) 

1 (2%) 

(49 ) 

1 (2%) 

1 (2%) 

26 (53%) 

2 (U%) 

16 (33%) 

' C*9) 

(46) 

1 (2S) 

(47) 

4 (9X) 

1 (2X) 

(49) 

(44) 

2 (5») 

69
 
TABLE C2. FEMALE RATS: NONNEOPLASTIC LESIONS (CONTINUED) 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

• PARATHYROI D (31 ) (31) (30 )

 

HYFEHPLAS-^A , NO S 1 (3% )

 

REPRODUCTIV E oYSTE M 

*SAMKAR Y GLAd D (50) (50) (49 ) 

GALACTOC£t, E 2 (4%) 14 (28%) 14 (293) 

LACTATIO N 1 (2%) 6 (12% ) 9 (18%) 

"VAGIN A (50) [50) (49 )

 

INFLAMMATION , NO S 1 (2X)

 

*UTERU S (50) (50) (49 ) 

HYDROMETR A 7 (14%) 1 (2%) 

CYST, NOS 2 (H%) 

THBOMBUS , ORGANIZE D 1 (2%) 

HEMORBHAGi C CYST 1 (2% ) 

FYOHETfi A 1 (2% ) 1 (2%) 

tUTERUS/INDOciETRIU M (50) (50) (49) 

HYPERPLASiA , CYSTIC 3 (6%) 1 (2%) 

#OVARY/FAROVftRIA N (50) (50) (49 )

 

NECROSIS, FAT 1 (2%)

 

#OVAR Y (49) (49) (49) 

CYST, NOS 1 (2%) 1 (255) 

FOLLICULAfi CYST, NOS 2 (H%) 

PAROVARIA N CYST 1 (2%) 

INFLAMMATION , NOS 1 (2%) 

NERVOU S SYSTEM 

•BRAIN (48) (48) C*9) 

COMPRESSION 3 ((,%) 5 (10%) 

HYDfiOCEPHALUS, NOS 1 (2%) 1 (2%) 

INFLAMHAT1ON , SUPPOHATIVE 1 (23t) 

SPECIAL SENSE ORGAN S 

*EYE (50) (50) (49)

 

INFLABHATION , NOS 1 J211 

# NUMBER OF ANIMALS HITH TISSUE EXAMINED HICROSCOPICALLY
 

* NUMBER OF ANIMALS NECROPSIED
 

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

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

CATARACT 1 (2%) 1 (255) 2 (U%) 

*EYE/P.ETINA (50) (50) (49 ) 

ATROPHY , jJOS 1 (2%) 3 (6%) 

*HARD£RIA N GLAN D (50) (50) (49) 

HYPERPLASJ.A , NOS 1 (2%) 

MUSCULOSKELETrtL SYSTEM 

NON E 

BODY CAVITIES 

*ABEOKINA L CAVIT Y (50) (50) (49) 

NECROSIS, FAT 3 (6%) 2 (1%) 4 (9%) 

*PERITONEA L CAVIT Y (50) (50) (49) 

NECROSIS , FAT 1 (255) 

A L L OTHER SYSTEM S 

*HULTIPLE ORGAN S (50) (50) (49 ) 

LEUKOCYTOoIS, NOS 1 (2%) 

SPECIAL MORPHOLOG Y SUMMAR Y 

NO LESIO N REPORTE D 2 

AUTOLYSIS/N O NECROPS Y 1 

* NUMBE R OF AwIMAL S WITH TISSUE EXAMINE D MICROSCOPICALLY 

* NUMBE R OF AhlflAL S NSCROPSIE D 

71 
72

 
APPENDIX D
 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS
 

IN MICE ADMINISTERED TITANIUM DIOXIDE IN THE DIET
 

73
 
74

 
TABLE 01. 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS IN MALE MICE 

ADMINISTERED TITANIUM DIOXIDE IN THE DIET 

_.	 —
 

ANIHALS INITIALLY IN STUDY
 

ANIMALS NECROPSIED
 

ANIMALS EXAMINED HI STOPATHOLOGICALL Y
 

INTEGUMENTARY SYSTEM
 

*SKIN
 

EPIDERMAL INCLUSION CYSI
 

INFLAMMATION, NOS
 

INFLAMMATION, FOCAL
 

INFLAMMATION, CHRONIC
 

HYPERKERATOSIS
 

ACANTHOSIo
 

*SUBCUI TISSUE
 

EDEMA, NOS
 

GRANUL02U, NOS
 

NECROSIS, FAT
 

RESPIRATORY SYSTEM
 

(fLUNG
 

CONGESTION, NOS
 

HEMORRHAGE
 

INFLAMMATxON, SUPPURATIVE
 

PN3UWONIA, CHRONIC MUR.INE
 

*LUNG/ALVEOLI
 

EPITHELIAi,lZATIGN
 

HEMATOPOIETIC SYSTEM
 

sSPLEEN
 

CONGESTION, NOS
 

HYPERPLASiA, LYMPHOIC
 

HSMATOPOIi^SIS
 

ifLYMPH NODE
 

__LYMPHANGIaCTASIS _
 

——————————— ———
 MATCHED
 

CONTROL LOW DOSE HIGH DOSE
 

50 50 50
 

47 49 49
 

47 49 49
 

(47)	 (49) (49)
 

1 (2%)
 

3 (6%)
 

1 (2%)
 

1 (2%)
 

2 (4%)
 

2 (4%)
 

(47) (49) (49)
 

1 [2%)
 

1 (2%)
 

1 (2%)
 

(46) (49) (49)
 

2 (H%)
 

1 (2%) 2 (45?)
 

1 (2%)
 

1 (2%) 5 (1035) 2 (4%)
 

(46)	 (49) (49)
 

1 (2S)
 

(47)	 (49) (49)
 

1 (255)
 

6 (12%)
 

3 (6%) 2	 (43) 5 (105)
 

(47)	 (46) (48)
 

1 (2%)
 

»	 NUKBSR OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

*	 NUMBER OF ANIMALS NSCROPSIED
 

75
 
TABLE 01. MALE MICE: NONNEOPLASTIC LESIONS (CONTINUED) 

*MZSENT£RI C *.. NOD E 

LYHPHANGI/5CTASI S 

HEMOHRHAG i 

PEBIARTERj-II S 

HYPSRPLASIA , RETICULU M CHLL 

HEMATOPOI^SI S 

CIRCULATOR Y SYSIE M 

»HEAR T 

PEaiARTEEiTIS
 

tAURICULAR APPENDAGE
 

THHOMBOSIo, NOS
 

DIGESTIVE SYSIEM
 

KSALIVARY GLAND
 

INFLAMMATION, NOS
 

SLIVER
 

CYST, NOS
 

THROMBUS, ORGANIZED
 

INFLAMMATION, CHRONIC
 

NECROSIS, NOS
 

NECROSIS, FOCAL
 

ANGIECTASiS
 

JLIVER/CENTfilLOBULAH
 

NECROSIS, NOS
 

*BIL£ DUCT
 

DILATATION, NOS
 

•PANCREAS
 

CYST, NOS
 

CYSTIC DOCTS
 

' PERIARTEEITIS
 

tSTOBACH

HYPEHKERATOSIS

A£ANTHOSIa

* NUMBE R OF AtflHALS WIT H TISSUE

* NUMBE R OF ANIMAL S NECROPSIED 

_____ ___—_. 

MATCHED 

CONTROL LOV VDOSE 

(47) (48) 

1 (2%) 12 (25S) 

1 (2%) 

1 (2%) 

(46) (49) 

(46)	 (49)
 

1 (2X)
 

(47) (48) 

1 (2X) 

(47) 

2 (4») 

(«7) (47) 

1 (2*) 

(47) (49) 

2 («X) 

(47) 

1 (2X) 

1 (2») 

 (47) 

2 (45i) 

 2_J4J).. 

 EXAHINE D MICROSCOPICALLY 

HIGH DOSE 

(48) 

15 (31%) 

1 (2%) 

4 (8») 

1 (2%) 

(49)
 

1 (2%)
 

(47) 

(49) 

1 (2%) 

1 (2%) 

2 (4X) 

8 (16J5) 

1 (2X) 

2 (<»X) 

(H9) 

149) 

(48) 

1 (2%) 

(49) 

76 
TABLE 01. MALE MICE: NONNEOPLASTIC LESIONS (CONTINUED) 

MATCHED 

CONTROL LOW DOSE 

*LARG3 INlESiINE (45) (49) 

NEMATODIAoIS 1 (2%) 

URINABY'SYSTE a 

• KIDNE Y (47) (49) 

INFLAMMATION , CHRONIC 4 (8») 

ANGIECTASiS 1 (2») 

HYPERPLASiA , LYMPHOI D 1 (2%) 

• URINAR Y ELAODE R (46) (49) 

POLYP 1 (2%) 

*U.BLADCtR/SJBMUCOS A (49)

 

EDEMA , NOS 

ENDOCRIN E SYSTEM 

NON E 

REPRODUCTIVE SYSTEM
 

*PREPUTIAL GJ.AND (47) (49) 

HYPERPLASIA , NOS 1 (2*)
 

((TEST IS (47) {49) 

GRANULOMA , SPERMATIC 1 (2X) 

ATROPHY , iiOS 1 (2%) 

*EPIDIDYMIS (47) (49) 

NECROSIS, FAT 1 (2X) 1 (2X) 

NERVOUS SYSTEM
 

NONE
 

SPECIAL SENSE ORGANS
 

*EYE/CORNEA (47) (49)
 

INFLAMMATION, NOS
 

t NUMBER OF ANIMALS HITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMBER OF ANIMALS NECROPSIED
 

HIGH DOSE 

(49 ) 

3 

(49) 

5 (10%) 

(49) 

(49) 

1 

(49)
 

(48)
 

1 (235)
 

(49)
 

(49)
 

77 
TABLE 01. MALE MICE: NONNEOPLASTIC LESIONS (CONTINUED) 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

VASCULAHI^ATIO N 1 (2%) 

flUSCULOSKELETAL

NON E 

 SYSTEM 

BOD Y CAVITIES 

*ABDOMINAL CaVITY

NECROSIS, FAT

 (47)

 1 (2%)

 (49)

 2 (4%) 

 (49) 

*MESENTERY

PERIAR1EEU1IS

 (47) (49) (49) 

1 (2X) 

ALL OTHS8 SYSIEHS 

NONE 

SPECIAL HORPHuLOGY SUMMARY 

NO LESION REPOETi-D 8

AUTO/NECRJPSY/HISTO PERF 1

AU10LYSIS/NO NECROPSY 3

» NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY 

* NUMBER OF Aid HALS NECROPSIED 

8

 1 

1

 10 

1 

78
 
TABLE 02.

 

SUMMARY OF THE INCIDENCE OF NONNEOPLASTIC LESIONS IN FEMALE MICE 

ADMINISTERED TITANIUM DIOXIDE IN THE DIET

 

„_._.._.__.... 

. 

MATCHED 

- CONTROL LOW DOSE HIGH DOSE 

ANIMALS INITIALLY IK STUDY 50 50 50 

ANIMALS MISSING 1 

ANIHALS UECROf SIED 49 50 50 

ANIMALS EXAMINED HISTOPATHOLOGICALLY 49 50 50 

INTEGUHENTABY SYSTEM
 

NONE
 

RESPIRATORY SYSTEM
 

#LUNG (49) (50) (50) 

CONGESTION, NOS 4 (855) 4 

HEMORRHAGE 1 (2X) 

PNEUMONIA, CHRONIC MURINE 3 (6X) 5 (10X) 5 (103S) 

HEilATOPOIETIC SYSTEM 

#SPLEEN (49) (50) (50)
 

HEMORBHAGj-C CYST 1 (235)
 

ATROPHY, NOS 1 (231 )


HYPEEPLASiA, LYMPHOID 7 (14S)
 

HEMATOPOISSIS 4 (8*) 2 (4S)
 

*MESENTERIC L. NODE (48) (47) (47)
 

LYBPHANGIiCTASIS 5 (11S)
 

HYPERPLASlA, LYMPHOID 5 (11S)
 

CIRCULATOR Y SYSTE M 

#HEAR T (49 ) (50) (50) 

THROMBCSIi , NOS 1 (2X) 

INFLAMMATION , CHRONIC 1 (2%) 

INFLAMMATION , CHRONI C FOCA L 1 (2%) 

FIBROSIS, FOCAL 1 (2JS) 

tfMYOCARDIU M (49 ) (50) (50) 

• NUMBE R O F ANIMAL S UIT H TISSUE EXAMINE D MICROSCOPICALL Y 

* NUMB2 R OF ArtlMAL S NSCROPSISD 

79 
TABLE 02. FEMALE MICE: NONNEOPLASTIC LESIONS (CONTINUED) 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

DIGESTIV E SYSTE M 

SLIVER (49 ) (50) (50) 

CONGESTION , NOS 1 (2%) 

INFLAMMATION , CHRONIC 1 (2%) 

DEGENERATION , LIPOID 1 (2%) 

NECBOSIS, FOCAL 1 (2%) 

INFAECT, NOS 1 (2%) 

FOCAL CELLULA R CHANG E 1 (2%) 

HYPEfiPLASiA , FOCAL 1 (27.) 

*BILE DUCT (49) (50) (50)
 

HYPERPLASxA, NOS 1 (2%)
 

IfPANCREAS (49) (50) (50)
 

CYST, NOS 1 (2%)
 

CYSTIC DUCTS 2 (4X) 1 (2%)
 

ATROPHY, dOS 1 (2%)
 

*PANCREATIC JUCT (49) (50) (50)
 

CONGENITAL MALFORMATION, NOS 1 (2«)
 

*PANCREATIC aCINUS (49) (50) (50)
 

ATHOPHY, i«OS 1 (2%)
 

fSTOMACH (48) (50) (49)
 

ULCER, FOCAL 1 (2%) 2 (4%)
 

HYPEBKERAiOSIS 1 (2%) 1 (2%) 1 (2%)
 

ACANTH03IJ 1 (2%) 1 (2X)
 

*SMALL INTESi'INE (t9) (50) (49)
 

INFLAMMATION, SUPPU8ATIVE 1 (2%)
 

#LAHGE INTESTINE (48) (50) (49)
 

NEHATODIAoIS 1 (2%) 1 <2S)
 

UBINAR Y SYSTEtl 

»KIDNEY (49) (50) (50)
 

INFLAMMATION, CHRONIC 1 (2%) 2 (4%) 1 (2%)
 

INFLAMMATION, CHRONIC FOCAL 3 (6%)
 

INFABCT, NOS 2 (4«)
 

« NUMBER OF AHIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMBER OF ANIMALS NECROPSIED
 

80
 
TABLE 02. FEMALE MICE: NONNEOPLASTIC LESIONS (CONTINUED) 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

ENDOCRINE SYSTEM 

*PITUITARY (33) (40) (33)

 

CYST, NOS 1 (335)

 

tTHYROID (41) (44)

 

HYPERPLASxA , FOLLICULAR-CEL L 2 (58)

 

aSPBODOCTIVE oYSTE M 

*MAMMAR Y GLAw D (49) (50) (50) 

METAPLASIn , SQUAMOU S 1 (2%) 

LACTATIO N 1 (2%) 

* UTERUS (48) (49) (49) 

HYDROMETR/ . 6 (1336) 3 (6*) 

THROMBOSIS, NOS 2 (4%) 

PYOMETR A 1 (2%) 

ANGIECTASi S 3 (635) 

fUTERUS/£NDOnZTEIU M (48) (49) (49 ) 

INFLAMMATION , SUPPURATIV E 1 (2%) 

HYPERPLASxA, CYSTIC 17 (35%) 42 (8655) 38 (78%) 

fOVAR Y (47) (47) (47) 

CYST, NOS 10 (21%) 

FOLLICULArt CYST, NOS 1 (2%) 11 (23%) 8 (17?) 

PAROVARIAri CYST 1 (2%) 1 (2%) H (9X) 

HEMOBRHAGI C CYST 2 (455) 

INFLAMMATION, NOS 1 (2%) 

INFLAMMATION , SUPPUHATIV E 1 (235) 

KHRVOUS SYSTiii
 

(49) (50)
 

MALACIA 1 (21)
 

SPECIAL SENSE ORGANS
 

*EYE/CORNEA (49) (50) (50)
 

# NUMBEE OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY
 

* NUMBER OF ANIMALS NECEOPSIEC
 

81
 
TABLE 02. FEMALE MICE: NONNEOPLASTIC LESIONS (CONTINUED) 

MATCHED 

CONTROL LOW DOSE HIGH DOSE 

*HARDERIAN GLAND

HYPERPLAEiA, NOS

 (i»9)

 1 (235) 

 (50) (50) 

MU3CULOSKELETAL SYSTEM 

NONE 

EODY CAVITIES 

NONE 

ALL OTHER SYSTEMS 

NONE 

SPECIAL MOEPHoIOGY SUMMARY 

NO LESION PEPORTED 3

ANIMAL MI5SING/NO NECROPSY 1 

* NUMBER OF ANIMALS WITH TISSUE EXAMINED MICROSCOPICALLY 

* NUMBER OF AuIMALS NSCROPSIED 

1 2 

82
 
APPENDIX E
 

ANALYSES OF THE INCIDENCE OF PRIMARY TUMORS
 

IN RATS ADMINISTERED TITANIUM DIOXIDE IN THE DIET
 

83
 

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

Administered Titanium Dioxide in the Diet3
 

Matched Low High
 

Topography: Morphology Control Dose Dose
 

Integumentary System:
 

Keratoacanthoma of the Skinb 0/49 (0) 0/50 (0) 3/50 (6)
 

P Values0 »d P = 0.038 N.S. N.S.
 

Relative Riskf Infinite
 —
 Lower Limit 0.590
 

Upper Limit Infinite
 

Weeks to First Observed Tumor 98
 

oo — —
 

Integumentary System:
 

Fibroma of the Skinb 1/49 (2) 5/50 (10) 5/50 (10)
 

P Values0 »d N.S. N.S. N.S.
 

Relative Riskf 4.900 4.900
 

Lower Limit 0.577 0.577
 

Upper Limit 226.749 226.749
 

Weeks to First Observed Tumor 100 99 69
 
Table El. Analyses of the Incidence of Primary Tumors in Male Rats
 

Administered Titanium Dioxide in the Dieta
 

(continued)
 

Matched Low High
 

Topography: Morphology Control Dose Dose
 

Hematopoietic System: Leukemia*3 14/49 (29) 8/50 (16) 6/50 (12)
 

P Values0>d P = 0.024(N) N.S. P = 0.035(N)
 

Relative Riskf 0.560 0.420
 

Lower Limit 0.224 0.144
 

Upper Limit 1.295 1.060
 

Weeks to First Observed Tumor 81 90 91
 

oo All Sites: Hemangiosarcoma^ 1/49 (2) 1/50 (2) 3/50 (6)
 

P Valesc>d N.S. N.S. N.S.
 

Relative Riskf 0.980 2.940
 

Lower Limit 0.013 0.246
 

Upper Limit 75.404 151.180
 

Weeks to First Observed Tumor 105 73 105
 
Table El. Analyses of the Incidence of Primary Tumors in Male Rats
 

Administered Titanium Dioxide in the Diet3
 

(continued)
 

Topography; Morphology
 

Pituitary: Chromophobe Adenoma*3
 

P Valuesc»d
 

Relative Riskf
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

oo Adrenal: Pheochromocytoma'3
 

P Valuesc»d
 

Relative Riskf
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Matched
 

Control
 

5/48 (10)
 

N.S.
 

103
 

7/49 (14)
 

N.S.
 

67
 

Low
 

Dose
 

10/50 (20)
 

N.S.
 

1.920
 

0.649
 

6.661
 

88
 

9/49 (18)
 

N.S.
 

1.286
 

0.464
 

3.742
 

99
 

High
 

Dose
 

7/46 (15)
 

N.S.
 

1.461
 

0.430
 

5.433
 

14/50 (28)
 

N.S.
 

1.960
 

0.816
 

5.238
 

101
 

73 
Table El.


(continued)
 

TopjD^raphy: Morphology


Thyroid: C-cell Carcinomab


P Valuesc»d


Relative Riskf
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor


oo Thyroid: C-cell Adenoma or
 

°° Carcinomab


P Valuesc»d


Relative Riskf
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor


 Analyses of the Incidence of Primary Tumors in Male Rats
 

Administered Titanium Dioxide in the Diet3
 

High'
 

Dose
 

1/50 (2)
 

N.S.
 

0.245
 

0.005
 

2.362
 

105
 

1/50 (2)
 

N.S.
 

0.245
 

0.005
 

2.362
 

105
 

Matched
 

 Control
 

 4/49 (8)
 

 N.S.
 

 81
 

 4/49 (8)
 

 N.S.
 

 81
 

Low
 

Dose
 

1/49 (2)
 

N.S.
 

0.250
 

0.005
 

2.409
 

104
 

4/49 (8)
 

N.S.
 

1.000
 

0.197
 

5.077
 

104
 
00 

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

Administered

(continued) 

Topography; Morphology
 

Pancreatic Islets: Islet-cell
 

Adenoma or Carcinoma"
 

P Values0 »d
 

Relative Riskf
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Mammary Gland: Fibroadenomab
 

P Values0 »d
 

Relative Riskf
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

 Titanium Dioxide in the Diet3 

Matched Low
 

Control Dose
 

1/49 (2) 2/50 (4)
 

N.S. N.S.
 

1.960
 

0.106
 

113.312
 

105 104
 

1/49 (2) 1/50 (2)
 

N.S. N.S.
 

0.980
 

0.013
 

75.404
 

105 101
 

High
 

Dose
 

3/50 (6)
 

N.S.
 

2.940
 

0.246
 

151.180
 

72
 

3/50 (6)
 

N.S.
 

2.940
 

0.246
 

151.180
 

99
 
Table El. Analyses of the Incidence of Primary Tumors in Male Rats
 

Administered Titanium Dioxide in the Diet3
 

(continued)
 

Topography; Morphology
 

Preputial Gland: Carcinoma, NOSb
 

P Values0>d
 

Relative Riskf
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Testis: Interstitial-cell Tumor or
 

Interstitial-cell Tumor, Malignant^5
 

P Values0 >d
 

Relative Riskf
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Matched
 

Control
 

2/49 (4)
 

N.S.
 

105
 

45/49 (92)
 

N.S.
 

78
 

Low
 

Dose
 

5/50 (10)
 

N.S.
 

2.450
 

0.424
 

24.778
 

73
 

46/49 (94)
 

N.S.
 

1.022
 

0.910
 

1.130
 

90
 

High
 

Dose
 

6/50 (12)
 

N.S.
 

2.940
 

0.558
 

28.662
 

69
 

41/50 (82)
 

N.S.
 

0.893
 

0.785
 

1.063
 

76
 
Table El. Analyses of the Incidence of Primary Tumors in Male Rats
 

Administered Titanium Dioxide in the Diet3
 

(continued)
 

a

Dosed groups received 25,000 or 50,000 ppm.
 

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

c

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


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

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

the comparison of that dosed group with the matched-control group when P < 0.05; otherwise,
 

not significant (N.S.) is indicated.
 

^A negative, (N), indicates a lower incidence in a dosed group than in a control group.
 

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

95% confidence interval of the relative risk between each dosed group and the control
 

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

Administered Titanium Dioxide in the Dieta 

Topography; Morphology


Integumentary System:
 

Squamous-cell Carcinoma b


P Valuesc»d


Relative Riskf
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor


Lung: Alveolar/Bronchiolar
 

Adenoma or Carcinoma'3


P Valuesc»d


Relative Riskf
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor


Matched Low High 

 Control Dose Dose 

 2/50 (4) 1/50 (2) 3/49 (6) 

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

0.500 1.531 

0.009 0.183 

9.290 17.671 

 85 80 90 

 3/50 (6) 1/50 (2) 1/49 (2) 

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

0.333 0.340 

0.006 0.007 

3.983 4.062 

 105 105 90 
Table E2. Analyses of the Incidence of Primary Tumors in Female Rats 

Administered Titanium Dioxide in the Diet3 

(continued) 

Matched Low High 

Topography; Morphology Control Dose Dose 

Hematopoietic System: 

Lymphoma or Leukemia" 10/50 (20) 13/50 (26) 12/49 (24) 

P Valuesc>d N.S. N.S. N.S. 

VJD Relative Riskf 1.300 1.224 to 

Lower Limit 0.583 0.536
 

Upper Limit 2.994 2.863
 

Weeks to First Observed Tumor 94 66 90
 

Pituitary: Carcinoma, NOSb 0/48 (0) 3/47 (6) 3/47 (6)
 

P Values0 »d N.S. N.S. N.S.
 

Relative Riskf Infinite Infinite
 

Lower Limit 0.615 0.615
 

Upper Limit Infinite Infinite
 

Weeks to First Observed Tumor 105 98
 
Table E2. Analyses of the Incidence of Primary Tumors in Female Rats
 

Administered Titanium Dioxide in the Diet3
 

(continued)
 

Topography; Morphology
 

Pituitary: Chromophobe Adenoma*5
 

P Values0 »d
 

Relative Riskf
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Thyroid: C-cell Carcinoma*3
 

P Values0 »d
 

Relative Riskf
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Matched Low High 

Control Dose Dose 

28/48 (58) 26/47 (55) 31/47 (66) 

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

0.948 1.131 

0.647 0.801 

1.390 1.584 

85 78 73 

1/48 (2) 0/47 (0) 4/44 (9) 

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

0.000 4.364 

0.000 0.454 

19.033 209.675 

105 105 — 
Table E2. Analyses of the Incidence of Primary Tumors in Female Rats
 

(continued)
 

Topography: Morphology
 

Thyroid: C-cell Adenoma
 

or Carcinoma'3
 

P Values0 >d
 

Departure from Linear Trend6
 

Relative Riskf
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Mammary Gland: Fibroadenoma"
 

P Values0 >d
 

Relative Riskf
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor
 

Administered Titanium Dioxide in the Diet3
 

Matched Low
 

Control Dose
 

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

P = 0.013 N.S.
 

P = 0.044
 

0.000
 

0.000
 

19.033
 

105
 

20/50 (40) 14/50 (28)
 

N.S. N.S.
 

0.700
 

0.373
 

1.283
 

98 78
 

High
 

Dose
 

6/44 (14)
 

P = 0.043
 

6.545
 

0.841
 

293.404
 

105
 

19/49 (39)
 

N.S.
 

0.969
 

0.565
 

1.658
 

86
 
Table E2.


(continued)
 

Topography: Morphology


Mammary Gland: Adenoma or
 

Adenocarcinoma, NOSb


P Values0 »d


Relative Riskf
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor


v£>
 

Preputial Gland: Carcinoma, NOSb


P Values0 »d


Relative Riskf
 

Lower Limit
 

Upper Limit
 

Weeks to First Observed Tumor


 Analyses of the Incidence of Primary Tumors in Female Rats
 

Administered Titanium Dioxide in the Diet3
 

Matched Low High 

 Control Dose Dose 

 1/50 (2) 2/50 (4) 3/49 (6) 

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

2.000 3.061 

0.108 0.256 

115.621 157.341 

 94 103 88 

 2/50 (4) 2/50 (4) 3/49 (6) 

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

1.000 1.531 

0.075 0.183 

13.326 17.671 

 105 105 105 
Table E2. Analyses of the Incidence of Primary Tumors in Female Rats
 

Administered Titanium Dioxide in the Dieta
 

(continued) 

Matched Low High 

Topography; Morphology Control Dose Dose 

Uterus /Endometrium:
 

Endometrial Stromal Polypb 7/50 (14) 15/50 (30) 10/49 (20)
 

P Values0 »d N.S. P = 0.045 N.S.
 

Relative Riskf 2.143 1.458
 

Lower Limit 0.907 0.546
 

Upper Limit 5.663 4.149
 

Weeks to First Observed Tumor 92 83 90
 

a

Dosed groups received 25,000 or 50,000 ppm.
 

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

c

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


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

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

the comparison of that dosed group with the matched-control group when P < 0.05; otherwise,
 

not significant (N.S.) is indicated.
 

°A negative, (N), indicates a lower incidence in a dosed group than in a control group.
 

e

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

95% confidence interval of the relative risk between each dosed group and the control
 

group.
 
6

 8
APPENDIX F
 

ANALYSES OF THE INCIDENCE OF PRIMARY TUMORS
 

IN MICE ADMINISTERED TITANIUM DIOXIDE IN THE DIET
 

99
 
100

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

Administered Titanium Dioxide in the Dieta 

Matched Low High
 

Topography: Morphology Control Dose Dose
 

Integumentary System: Fibroma^ 4/47 (9) 4/49 (8) 1/49 (2)
 

P Valuesc»d N.S. N.S. N.S.
 

Relative Riskf 0.959 0.240
 

Lower Limit 0.189 0.005
 

Upper Limit 4.867 2.309
 

Weeks to First Observed Tumor 98 104 104
 

Integumentary System: Fibrosarcoma
 

of the Subcutaneous Tissueb 8/47 (17) 8/49 (16) 4/49 (8)
 

P Values0 >d N.S. N.S. N.S.
 

Relative Riskf 0.959 0.480
 

Lower Limit 0.342 0.113
 

Upper Limit 2.692 1.662
 

Weeks to First Observed Tumor 89 75 95
 
Table Fl. Analyses of the Incidence of Primary Tumors in Male Mice 

Administered Titanium Dioxide in the Dieta 

(continued) 

Matched Low High 

Topography: Morphology Control Dose Dose 

Lung: Alveolar/Bronchiolar
 

Adenoma or Carcinoma'-' 6/46 (13) 3/49 (6) 5/49 (10)
 

d
 P Values0> N.S. N.S. N.S.
 

Relative Riskf 0.469 0.782
 

Lower Limit 0.080 0.202
 

Upper Limit 2.060 2.868
 

Weeks to First Observed Tumor 104 102 104
 

Hematopoietic System:
 

Lymphoma or Leukemia" 6/47 (13) 7/49 (14) 5/49 (10)
 

d
 P Values0> N.S. N.S. N.S.
 

Relative Riskf 1.119 0.799
 

Lower Limit 0.348 0.207
 

Upper Limit 3.742 2.932
 

Weeks to First Observed Tumor 74 75 101
 
Table Fl. Analyses of the Incidence of Primary Tumors in Male Mice
 

Administered Titanium Dioxide in the Dieta
 

(continued) 

Matched Low High 

Topography; Morphology Control Dose Dose 

Liver: Hepatocellular Carcinoma" 8/47 (17) 9/47 (19) 14/49 (29)
 

P Values0>d N.S. N.S. N.S.
 

Relative Riskf 1.125 1.679
 

Lower Limit 0.422 0.729
 

Upper Limit 3.061 4.183
 

Weeks to First Observed Tumor 89 102 94
 

a

Dosed groups received 25,000 or 50,000 ppm.
 

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

c

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


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

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

the comparison of that dosed group with the matched-control group when P < 0.05; otherwise,
 

not significant (N.S.) is indicated.
 

^A negative, (N), indicates a lower incidence in a dosed group than in a control group.
 

e

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

95% confidence interval of the relative risk between each dosed group and the control
 

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

Administered Titanium Dioxide in the Diet3
 

Matched Low High
 

Topography: Morphology Control Dose Dose
 

Lung: Alveolar/Bronchiolar
 

Adenoma or Carcinoma" 1/49 (2) 2/50 (4) 4/50 (8)
 

P Values0 >d N.S. N.S. N.S.
 

Relative Risk/ 1.960 3.920
 

Lower Limit 0.106 0.407
 

Upper Limit 113.312 188.989
 

Weeks to First Observed Tumor 104 105 103
 

Hematopoietic System:
 

Lymphomas or Leukemias^ 20/49 (41) 11/50 (22) 14/50 (28)
 

P Values0 »d N.S. P = 0.035(N) N.S.
 

Relative Riskf 0.539 0.686
 

Lower Limit 0.264 0.366
 

Upper Limit 1.046 1.256
 

Weeks to First Observed Tumor 81 92 70
 
Table F2. Analyses of the Incidence of Primary Tumors in Female Mice
 

Administered Titanium Dioxide in the Dieta
 

(continued) 

Matched Low High 

Topography; Morphology Control Dose Dose 

All Sites: Hemangiosarcomas^ 3/49 (6) 1/50 (2) 0/50 (0)
 

P Valuesc»d N.S. N.S. N.S.
 

Relative Riskf 0.327 0.000
 

Lower Limit 0.006 0.000
 

Upper Limit 3.903 1.629
 

Weeks to First Observed Tumor 102 50
 —
 

Liver: Hepatocellular Carcinoma^3 1/49 (2) 3/50 (6) 3/50 (6)
 

P Values0>d N.S. N.S. N.S.
 

Relative Riskf 2.940 2.940
 

Lower Limit 0.246 0.246
 

Upper Limit 151.180 151.180
 

Weeks to First Observed Tumor 104 105 105
 
Table F2. Analyses of the Incidence of Primary Tumors in

Administered Titanium Dioxide in the Diet3 

(continued) 

Matched Low
 

Topography; Morphology Control Dose
 

Pituitary: Chromophobe Adenoma** 3/33 (9) 4/40 (10)
 

P Valuesc»d N.S. N.S.
 

Relative Riskf 1.100
 

Lower Limit 0.201
 

Upper Limit 7.050
 

Weeks to First Observed Tumor 104 105
 

,_, Thyroid: Follicular-cell Adenoma*1 3/43 (7) 0/41 (0)
 

o
 

P Valuesc»d P = 0.037(N) N.S.
 

Relative Risk^ 0.000
 

Lower Limit 0.000
 

Upper Limit 1.733
 

Weeks to First Observed Tumor 104
 —
 

 Female Mice 

High
 

Dose
 

2/33 (6)
 

N.S.
 

0.667
 

0.059
 

5.439
 

0/44 (0)
 

N.S.
 

0.000
 

0.000
 

1.618
 

—
 

105 
Table F2. Analyses of the Incidence of Primary Tumors in Female Mice
 

Administered Titanium Dioxide in the Diet3
 

(continued)
 

Matched Low High
 

Topography: Morphology Control Dose Dose
 

Mammary Gland: Adenocarcinoma, NOS^ 1/49 (2) 1/50 (2) 3/50 (6)
 

P Values0»d

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

Relative Riskf 0.980 2.940
 

Lower Limit 0.013 0.246
 

Upper Limit 75.404 151.180
 

Weeks to First Observed Tumor 104 105 90
 

a

Dosed groups received 25,000 or 50,000 ppm.
 

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

c

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


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

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

the comparison of that dosed group with the matched-control group when P < 0.05; otherwise,
 

not significant (N.S.) is indicated.
 

^A negative, (N), indicates a lower incidence in a dosed group than in a control group.
 

e

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

95% confidence interval of the relative risk between each dosed group and the control
 

group.
 
108

 
APPENDIX G
 

ANALYSIS OF FORMULATED DIETS FOR
 

CONCENTRATIONS OF TITANIUM DIOXIDE
 

109
 
110

 
APPENDIX G
 

Analysis of Formulated Diets for
 

Concentrations of Titanium Dioxide
 

Duplicate 100-mg subsamples of feed were ashed, and the residues
 

fused with 2 g of potassium pyrosulfate. The fusion mixture was
 

quantitatively transferred to a 100-ml volumetric flask using a
 

1:1 mixture of sulfuric acid and water, and diluted to volume
 

with water. With a Tiron indicator, the transmittance of this
 

solution was read at 410 nm. Concentrations of titanium dioxide
 

were determined by comparison with standard solutions.
 

Recoveries were also determined from duplicate analyses of spiked
 

samples worked up simultaneously with each set of dosed feed
 

samples. The average recovery from the 2.5% spiked samples was
 

97.5%, and from the 5.0% spiked sample, 100.3%.
 

Theoretical No. of Sample Coefficient of Range 

Concentrations Samples Analytical Variation (%) (% in diet) 

in Diet Mean 

(% in diet) (% in diet) 

2.5 10 2.4 26.3 2.2-2.9*
 

5.0 12 4.9 29.5 4.79-6.85*
 

Ranges exclude the two samples at each level during weeks 35 and 45 which
 

analyzed at only 40-50% of the theoretical; these samples were included in
 

the Number of Samples, Sample Analytical Mean, and Coefficient of
 

Variation.
 

Ill
 

Review of the Bioassay of Titanium Dioxide* for Carcinogenicity by the
 

Data Evaluation/Risk Assessment Subgroup of the
 

Clearinghouse on Environmental Carcinogens
 

August 31, 1978
 

The Clearinghouse on Environmental Carcinogens was established in
 

May, 1976, in compliance with DHEW Committee Regulations and the Provisions of the Federal Advisory Committee Act. The purpose of the
 

Clearinghouse is to advise the Director of the National Cancer Institute
 

(NCI) on its bioassay program to identify and to 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 chemistry, biochemistry,
 

biostatistics, toxicology, pathology, and epidemiology. Representatives
 

of various Governmental agencies participate as ad hoc members. The
 

Data Evaluation/Risk Assessment Subgroup of the Clearinghouse is charged
 

with the responsibility of providing a peer review of reports prepared
 

on NCI-sponsored bioassays of chemicals studied for carcinogenicity. It
 

is in this context that the below critique is given on the bioassay of
 

Titanium Dioxide for carcinogenicity.
 

The primary reviewer said that Titanium Dioxide did not significantly
 

increase the incidence of tumors in treated mice, under the conditions
 

of test. In treated high dose female rats, however, he noted an increased
 

incidence in C-cell adenomas and carcinomas of the thyroid. Although
 

the staff did not find the thyroid tumors to be statistically significant,
 

the primary reviewer emphasized that the evidence was insufficient to
 

conclude that Titanium Dioxide was not carcinogenic. He recommended
 

that the report be accepted with the conclusion modified to indicate the
 

equivocal findings in female rats. He suggested that the compound be
 

considered for retest based on its wide human exposure and unclear findings
 

in treated female rats.
 

The secondary reviewer agreed with the conclusion in the report
 

that Titanium Dioxide was not carcinogenic, under the conditions of
 

test. He considered the study to be adequate. He noted the increased
 

incidence of C-cell adenomas and carcinomas of the thyroid in treated
 

female rats, but did not consider it to be significant. Based on the
 

results of the study, the secondary reviewer concluded that Titanium
 

Dioxide would not appear to pose a carcinogenic risk to humans.
 

113
 
A Program staff member said that the incidence of C-cell tumors of
 

the thyroid was not an unexpected finding in the Fischer rat. As a
 

result, he found no evidence to contradict the conclusion that Titanium
 

Dioxide was not carcinogenic under the conditions of test. He questioned
 

whether a. new study could be designed that would be a significant
 

improvement over this bioassay.
 

As suggested wording for a revised conclusion, the primary reviewer
 

proposed the following. "It was, concluded that, under the conditions of
 

this bioassay, Titanium Dioxide was not carcinogenic by the oral route
 

of exposure for B6C3F1 mice, but that no firm conclusion can be reached
 

about the possible carcinogenicity of this compound to Fischer 344 rats,
 

at this time." There was no objection to the recommendation that the
 

conclusion be modified as suggested. There also was no objection to
 

the recommendation that Titanium Dioxide be considered for retest.
 

Members present were:
 

Arnold Brown (Chairman), University of Wisconsin Medical School
 

Joseph Highland, Environmental Defense Fund
 

Michael Shimkin, University of California at San Diego
 

Louise Strong, University of Texas Health Sciences Center
 

(Kenneth Wilcox, Michigan State Health Department, submitted a written review)
 

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.
 

114
 

DHEW Publication No. (NIH) 79-1347