2 

## Table of Contents

1. EXECUTIVE SUMMARY

................................ ................................ ................................ .......................... 2 Regulatory Recommendation

................................ ................................ ................................ ................... 5

2. BAC KGROUND

................................ ................................ ................................ ................................ ....... 5

3. SUMMARY OF USES

................................ ................................ ................................ .............................. 6

4. PHYSICAL AND CHEMICAL PROPERTIES

................................ ................................ ................................ 6

5. HUMAN HEALTH ASSESSMENT

................................ ................................ ................................ ............. 7

5.1 Su mmary of Toxicity Data

................................ ................................ ................................ ............. 7

5.2 Toxicity Endpoint Selection

................................ ................................ ................................ ......... 21

6. EXPOSURE ASSESSMENT

................................ ................................ ................................ ..................... 22

6.1 Cancer.

................................ ................................ ................................ ................................ ........ 22

7. RESIDENTIAL EXPOS URE/RISK PATHWAY

................................ ................................ ........................... 23

8. AGGREGATE RISK AND DETERMINATION OF SAFETY

................................ ................................ ......... 23

8.1 Acute Aggregate Risk

................................ ................................ ................................ .................. 23

8.2 Short

- Term/Intermediate

- Term Aggregate Risk

................................ ................................ ......... 24

8.3 Long

- Term Aggregate Risk

................................ ................................ ................................ .......... 24

9. OCCUPATIONAL EXPOSURE/RISK PATHWAY

................................ ................................ ...................... 24

9.1 Handler Risk

................................ ................................ ................................ ................................ 24

9.2 Occupational Post Application Risk

................................ ................................ ............................. 25

10. CUMULATIVE EXPOSURE

................................ ................................ ................................ ................ 25

11. ENVIRONMENTAL FATE CONSIDERATIONS

................................ ................................ ..................... 25

12. ECOTOXICITY

................................ ................................ ................................ ................................ ... 25

13. ENVIRONMENTAL JUSTICE STATEMENT

................................ ................................ ......................... 26

14. RISK CHARACTERIZATION

................................ ................................ ................................ ................ 27

REFERENCES

................................ ................................ ................................ ................................ ................ 28



### 1. EXECUTIVE SUMMARY3

United Phosphorus, Inc. submitted a petition ( PP 1E7918 ) req uesting an amendment of a n exist ing tolerance exemption for the food use inert ingredient, t itanium dioxide (CAS Reg. No. 13463

- 67

- 7 ) when used as a pesticide in or on growing crops as an inert ingredient (UV protectant) in microencapsulated formulations of the insecticide lambda

- cyhalothrin at no more than 3.0% by weight of the formulation (40 CFR § 180.1195). The petitioner wishes to amend 40 CF R § 180.1195 to include the use of titanium d ioxide as an inert ingredient (UV

- st abilizer) at no more than 5% in napropamide pesticide formulations

.

T he titanium dioxide that will be used is pigmentary grade which is between 0.25 μm (250 nm) and 80 μm (80,000 nm) and not considered a nano

- material. The open literatu re acute toxicity studies show that titanium dioxide has very low acute toxicity. Acute oral and dermal toxicity studies have titanium dioxide categorized as EPA Toxicity Category IV. Eye irritation was also given an EPA Toxicity Category IV rating. Titanium dioxide is also not considered a sensitizing agent. No acute inhalat ion study was submitted but a lung inst i llation study provided by the petitioner showed statistically significant amount of inflammation immediately after the exposure but was not present after one month with concentrations up to 10 mg/kg.
In a 28 day l ung inst i llation open literature subchronic toxicity study, one formulation of titanium dioxide with silicon ha d a slight fibrogenic effect however the toxicity of other formulations of titanium dioxide were compar able to that of a nuisance dust. In a 90 d ay lung inst i llation study, there were statistically significant signs of inflammation immediately after exposure but were absent aft er one month.

In mice and rats, a 90 day oral toxicity study and chronic carcinogenicity studies were performed by the National Cancer Institute (NCI) via dietary route of exposure to titanium dioxide
, T here was no oral toxicity present at doses up to 50,000 ppm based on mortality, mean body weight gain, pathological findings or clinical observations in mice and rats

. In a separate study, t wo groups of 10 male and 10 female rats were given 0 or 10 percent (approximately 100,000 ppm) N.F. grade TiO 2 in their diet for 30

- 34 days. No treatment related effects were observed in this study ( West, B.Wyzan, H., 1963). Three grou ps of two dogs were given orally 0.05, 0.1 and 0.15 g of TiO 2 . Every five days the dose was increased by the same amounts. One dog of each group was kept for one month, the other for two months. No toxic effects were seen in dogs (Vernetti

- Blina, 1928). In a study with t wo guinea

- pigs, two rabbits, two cats and one dog were fed technical grade TiO 2 for 390 days. The dog received 9 g/day, rabbits and cats , 3 g/day, guinea pigs 0.6 g/day. No signs of systemic toxicity w ere observed in these animals (Lehmann & Herget, 1927).
A three months subchronic toxicity study was conducted on albino rats fed diets co ntaining 0, 1.0, 3.16 and 10 % with titanium dioxide coated

- mica (T CM )

. No compound related effects on behavior, growth, food consumption or mortality were observed. Organs and tissues showed neither consistent
gross changes nor histopathological changes that could be attributed to dietary administration of TCM.

In a male reproducti ve parameter study, a LOAEL was determined to be 1% titanium dioxide in the d iet which is estimated to be about 500 mg/kg/day, however the particle size used for testing was4

not reported and thought to be nanosized based on its comparative toxicity to other nanosized studies in the open literature

. No other reproductive or develop mental studies were provided.
The results of genotoxicity test on titanium dioxide are mixed. B ased on f our open litera ture genetic toxicity studies with titanium dioxide , human lymphocytes and SCE were increased in a dose

related manner at titanium dioxide concentrations of 2 μM and above and micronuclei were increased at concentrations of 5 μM and above. Titanium dioxide did not induce micronuclei in BEAS 2B cells. Treatment of both BEAS 2B and A594 cells with titanium dioxide resulted in DNA damage as measured in the Comet assay , h owever there were no increase s in the formation of 8

- oxoguanine in rat lung tissue, indu ction of gene mutations in the Ames assay or chromosomal aberrations in vitro in Chinese hamster ovary cells. The International Agency for Research on Cancer ( IARC ) in 2010 concluded that in vivo studies have shown enhanced micronucleus formation in bone marrow and peripheral blood lymphocytes of intraperitoneally instilled mice. Increased HPRT mutations were seen in lung epithelial cell s isolated from titanium dioxide instilled rats. In another study no enhanced oxidative DNA damage was observed in lung tissue of rats that were intratracheally instilled with t itanium dioxide . The results of most in vitro genotoxicity studies with t itaniu m dioxide were negative.

IARC concluded that t itanium dioxide was possibly carcinogenic to humans (Group 2B) on the basis of an inhalation carcinogenicity study in rats (Heinrich et al. 1995)

. However, IARC also concluded that titanium dioxide did not induce tumors by oral, intraperitoneal or subcutaneous routes of exposure in rats or mice

. In a Bioassay of titanium dioxide performed by the National Cancer Institute (NCI), groups of 50 rats of each sex and 50 mice of each sex were administered titanium dioxide in the diet at 25,000 or 50,000 ppm (or mg/kg) for 103 weeks . They concluded that under the conditions of the bioassay, titanium dioxide was not carcinogenic by the oral route for Fischer 344 rats or B6C3F1 mice. 

### A chronic dietary study administrati on of titanium dioxide coated mica at 0, 1, 2 and 5% in Fischer 344 rats for 130 weeks showed no toxicological or carcinogenic effects (Bernard et al ., 1990).
Based on the physiochemical properties of titanium dioxide, it is believed to be stable and persi stent in the environment. Titanium minerals are very abundant in the Earth’s crust and therefore a background level of exposure to t itanium dioxide will need to be taken into account throughout the
assessment. Ecotoxicity studies also showed that t itaniu m dioxide is practically non

- toxic to freshwater fish, invertebrates and algae on an acute toxicity bases. Due to low absorption through oral and dermal routes, terrestrial exposure of titanium dioxide as an inert ingredient in pesticide formulations to no n target organisms is thought to be of little concern.
The available toxicity studies on titanium dioxide via oral route of exposure clearly demonstrate lack of toxicity. The several studies in mice, rats, dogs, cats, rabbits and other species of varying durations do not indicate toxicity at very high doses (e.g. 50,000 ppm dietary exposure for two years in rats). No end point of concern via oral route of exposure has been identified in the available database. Therefore, dietary exposure was not conducted. This conclusion is in agreement with t he World Health Organization (WHO) Committee on Food Coloring Materials had determined that no ADI need be set for the use of titanium dioxide based on the range of acute, sub

- acute and chronic toxicity assays, all sh owing low mammalian toxicity. Similarly, no significant toxicity of titanium dioxide is expected via the5

dermal route of exposure. All currently registered uses of titanium dioxide as an inert ingredient in lambda

- cyhalothrin , and all anticipated uses of titanium dioxide as an inert ingredient in napropamide formulations , do not include residential applications. Therefore no residential risk assessment was performed. The available inhalation studies indicate that the primary toxicity of titanium dioxide is due to deposition of the inhaled particles and also suggest possible carcinogenic effects due to prolong exposure. The occupational inhalation exposure assessment was not conducted based on its requested use pattern and no direct exposure to titanium d ioxide particles is expected in pesticide napropamide formulations (less than 5% in formulations). T he actual environmentally anticipated exposures of titanium dioxide based on the use patterns of products that would contain titanium dioxide are orders of magnitude less than that allowed by the Occupational Safety and Health Administration ’s (OSHA) Permissible Exposure Limit (PEL)

. Regulatory Recommendation Taking into consideration all available information on titanium dioxide, EPA concludes that there is a reasonable certainty that no harm will result to the general population when titanium dioxide is used as an inert ingredient. The establishment of an exemption from tolerance for food use for residues of titanium dioxide when used as an inert ingredient ( UV protectant) applied to growing crops in pesticide formulations containing the active ingredient napropamide at no more than 5.0% by weight of the formulation can be considered safe under section 408 of the FFDCA. This approval granted only for the use of micronized form of titanium dioxide and nano sized is prohibited.



### 2. BACKGROUND

United Phosphorus, Inc. submitted a petition ( PP 1E7918) requesting an amendment of a tolerance exemption for a food use inert ingredient, t itanium dioxide (CAS Reg. No. 13463

- 67

- 7)
, when used as an inert ingredient (UV protectant) in microencapsulated formulations of the insecticide lambda

cyhalothrin at no more than 3.0% by weight of the formulation (40 CFR § 180.1195). United Phosphorus, Inc. wishes to amend 40 CFR § 180.119 5 to include the use of titanium dioxide as an inert ingredient (UV

- stabilizer) at no more than 5% in pesticide formulations containing the active ingredi ent

n apropamide. Napropamide is a systemic herbicide formulated as an emulsifiable concentrate, wettable powder, granule, and suspension concentrate. Application methods include aerial, ground boom, hand

held sprayers, granular application and chemigation. Napropamide is registered for use on cranberries, strawberries , toma toes, peppers, tobacco, nut trees, small fruits, vegetables, field

- grown nursery stock, liner stock, dichondra , and container

- grown ornamentals

.
Titanium dioxide has two exemptions from the requirement of a tolerance 40 CFR § 180.920 pesticide formulation s applied to growing crops as a pigment/colorant in plastic bags used to wrap bananas , colorant on seeds for planting and 40 CFR § 180.930 pesticide formulations applied to animals as a pigment/colorant in animal tags

. A Food Quality Protection Act (FQPA) reassessment was performed on titanium dioxide in June 2005 for these two exemptions from a tolerance

. Some of the background , conclusions and discussion will be ca rried over into this document. Titanium dioxide is also6

approved for use as a colorant in f ood (21 CFR § 73.575), in drugs (21 CFR § 73.1575), and in cosmetics (21 CFR § 73.2575; 21 CFR § 73.3126). There has also been a previous exemption , also listed above, from requirement of a tolerance for residues in or on growing crops, when used as an ine rt ingredient (UV protectant) in microencapsulated formulations of the insecticide lambda

- cyhalothrin at no more than 3.0% by weight or the formulations (40 CFR § 180.1195) which was established in March 1998 and therefore not included in the 2005 FQPA tolerance reassessment

.
Titanium dioxide is a naturally occurring mineral found predominately in ilmenite (FeTiO 3 ) and rutile ( t itanium dioxide ) forms. Titanium itself is one of the most abundant elements in the earth’s crust. It is mined in Australia, So uth Africa, Canada and the United States. Titanium dioxide is manufactured in high purity (>99%) and is available as microsized or nanosized particles. The registrant specifically and repeatedly states that they will be using only microsized pigmentary gra de titanium dioxide particles with size range from 0.25 μm (250 nm) to 80 μm (80,000 nm). While t here are open literature sources which discuss the toxicity of nanosized titanium dioxide particle s, only studies which contributed useful information regardin g microsized titanium dioxide particles are referenced herein.



### 3. SUMMARY OF USES

Titanium dioxide is a widely used inorganic white pigment that is produced from mined sources of titanium. Titanium dioxide pigments are white inorganic pigments used primaril y in the production of paints, printing inks, paper and plastic products. Titanium dioxide is also used in many white or colored products including foods, cosmetics, UV skin protection products, ceramics, fibers, and rubber products. It is also used as an inert ingredient in pesticide formulations as previously mentioned above.



### 4. PHYSICAL AND CHEMICAL PROPERTIES

Table 1. Physical and Chemical Properties of T itanium D ioxide
Parameter Value Source Structure ChemIDplusLite

CAS # 13463

- 67

- 7 ChemIDplusLite Molecular Weight (g/mol) 7 9.865 ChemIDplusLite Physical State Solid ChemIDplusLite Color White Registrant Submission Odor Odorless Registrant Submission pH Not applicable. P ractically insoluble in water.7

Melting Point ( in °C) 1843 HSDB 2005 Boiling Point ( in °C) Not applicable to solids. Density (in kg/m 3 at 25°C) 3.5 (anatase)

– 4.2 (rutile) The Merck Index Dissociation Constant (pK a ) Not applicable. Titanium dioxide contains no chemical functional group that readily dissociates. Particle size, fiber length, and diameter distribution Median particle size > 100 nm (non

nano) Registrant Submission

Vapor Pressure ( in hPa at 25°C) Not applicable

. Partition Coefficient ( Kow ) Not applicable

. Water Solubility (in mg/L at 20 °C) Insoluble in water, hyudrochloric, dilute sulfuric and organic solvents. Dissolves slowly in hydrofluoric acid hot concentrated sulfuric acid. The Merck Index, IPCS 1993

Henry’s Law Constant (in atm

m 3 /mole at 25°C) Not applicable

.



### 5. HUMAN HEALTH ASSESSMENT

5.1 Summary of Toxicity Data

Acute Toxicity Summary All studies summarized in table below are from MRID 48587801 and include only open literature studies. It cannot be c onfirmed whether the studies followed U.S. EPA guideline or not therefore all submitted studies under this MRID are assumed to be non

- guideline studies.

Table 2. Summ ary of Acute Toxicity Data for Titanium D ioxide
Parameter Toxicity Value Toxicity Category Reference

(MRID : 48587801 ) Acute Oral LD 50 , Rat >5000 mg/kg IV Warheir, D., Hoke, R., Finlay, C. et al. 2007 (open literature) Acute Oral LD 50 , Mice >5000 mg/kg IV Wang, J., Zhou, G., Chen, C. et al. 2007 (open literature) Acute Inhalation NOAEL, Rat 10 mg/kg N/A Warheir, D., Hoke, R., Finlay, C. et al. 2007 (open literature) Eye Irritation, Rabbit C onjunctival redness from 24

to 48 hrs after instillation. I II Warheir, D., Hoke, R., Finlay, C. et al. 2007 (open literature) Acute Dermal No skin irritations were IV W arheir, D., Hoke, R.,8 Irritation, Rabbit observed. Finlay, C. et al. 2007 (open literature) Skin Sensitization, LLNA Product is not a sensitizer Not a Sensitizer Warheir, D., Hoke, R.,

Finlay, C. et al. 2007 (open literature)

Acute Oral In an acute oral toxicity study (Warheir, D., Hoke, R., Finlay, C. et al 2007) a single dose of ultrafine particle type C ( uf

- C ) TiO 2 (80:20 ratio of anatase:rutile titanium dioxide; particle size 0.140 μm) suspended in water was administered by gavage to one female (fasted; species unspecified) rat each at a dose of 175, 550 or 1750 mg/kg and to three females (fasted ) at a dose of 5000 mg/kg. The study was run according to the acute oral toxicity test

up and down procedure. The rats were observed for morta lity, clinical signs of toxicity and body weight effects for 14 days. A complete necropsy was performed on each rat at the time of sacrifice. There were no mortalities. The only clinical sign observed was grey feces. There were no effects on body weights n or were there any gross findings. The oral LD 50 of uf

- C titanium dioxide was >5000 mg/kg.

In another acute oral toxicity study (Wang, J., Zhou, G., Chen, C. et al. 2007), ultrafine titanium dioxide particles (0.155 μm; >99% pure) suspended in 0.5% hydroxypropyl methylcellulose K4M were administered by gavage to CD

- 1 (ICR) 9 male and 8 female mice at a dose of 5000 mg/kg. Two different nanosized particles were also examined in this study for comparative purposes; however, the results are not summariz ed herein. Two weeks after the single dose all mice were sacrificed. All mice survived the 14 day period. Body weights and liver, spleen and kidney weights were unaffected. None of the serum parameters evaluating liver toxicity, nephrotoxicity and cardiac toxicity were affected by treatment. The livers of male and female mice examined microscopically had hydrospic degeneration around the central vein and spotty hepatocytic necrosis. Upon microscopic examination the heart, lung, testes, ovary and spleen had no findings. The LD 50 was greater than 5000 mg/kg/day.

Acute Inhalation In a acute inhalation study ( Warheit, D., Hoke, R., Finlay, C. et al. 2007), groups of Crl:CD(SD)IGS BR male rats were intratracheally instilled titanium dioxide formulations at doses of 0, 2 or 10 mg/kg. The particles were suspended in saline. Twenty

- four hours, one week and 1 and 3 months after instillation, 8 rats/ time point were sacrificed. The lungs of 4 rats/time point were assessed using both bronchoalveolar biomarkers and the lungs of the other 4 rats were examined for histopathology/cell proliferation. The numbers of cells recovered by bronchoalveolar lavage from the lungs of the titanium dioxide exposed groups were not significantly different from the controls at any time po int after exposure. At 2 mg/kg, H

- 11,567 and H

- 1 1,569 produced a short

- term pulmonary9 inflammatory response as shown by an increase in the numbers and percentage of bronchoaveolar lavage neutrophils at the 24 hour time point. The same inflammatory
response was also observed at 24 hours in all groups exposed to 10 mg/kg. Exposures to 10 mg/kg H

- l 1,567 and H

- l 1,569 produced a more sustained lung inflammatory response which persisted to the one month time p oint for H

- 1 1, 569 and to three months for H

1 1,567.

Examination of the bronchoav eolar lavage fluid from the H

- 11,565 and H

- 1 1,566 groups treated at 10 mg/kg revealed an increase in lactate dehydrogenase values at the 24 hour time point that were not observed at the late r time points. Exposures to H

- 1 1,569 produced significant increases in lactate dehydrogenase values at t he one week time point. The H

1 1,567 formulation produced a sustained increase in this parameter through the one month time point. Transient significant increase in bronchoaveloar fluid mic roprotein values were observed i n the lungs of the 10 mg/kg H

- 1 1,566 and H

- 11.568 at the 24 hour time point, but did not persist. H

- 1 1,569 produced a significant increase in microprotein at 1 week . H

1 1,567 caused sustained increased in lung permeability e ndpoints through one week post exposure. No increase in alkaline phosphatase values or in BrdU lung cell proliferation rates in parenchymal cells was observed.

Microscopic examination of the lungs of the rats instilled with the titanium dioxide formulatio ns revealed no significant morphological differences between the formulations. The lung tissues had particle

- laden macrophages at bronchoalveolar junctions following instillation. There were no other findings. The NOAEL was 10 mg/kg for the 99% TiO 2 1% co

o xidized Al 2 O 3 , the least formulated material.

In a acute lung instillation toxicity study (Ogami, A., Morimoto, Y., Myojo, T. et al. 2007), titanium dioxide was intratracheally administered into the lungs of 25 male Wistar rats at dose of 2 mg per 0.4 mL of saline. The control group received only saline. Five rats were sacrificed at each of five time points for examination of lung tissue: 3 days, one week, one month, three months and six months after instillation. Titanium dioxide was one of several materi als tested. Other test materials included silicon carbide whiskers, potassium oxtatanate whiskers, crystalline silica and crocidolite asbestos. Only the data generated on titanium dioxide will be summarized herein.

Titanium dioxide was intratracheally adm inistered into the lungs of 25 male Wistar rats at dose of 2 mg per 0.4 ml of saline. The control group received only saline. Five rats per sacrificed at each of five time points for examination of lung tissue: 3 days, one week, one month, three months and six months after instillation. The particle size of the titanium dioxide used was 1.5 μ m (GSD = 1.8). Lung inflammation and collagen deposition rate were scored. Paraffin sections of the left lung were stained with hematoxylin

- eosin and by the van Gieson method. Lung inflammation was scored by placing a 300

- point grid over each lung image (focusing mainly on the alveoli with five images/lung) on a computer screen.10 Pulmonary inflammation was examined by the point counting method. The percentage of the areas of inflammation excluding air spaces in the lung parenchyma was calculated. The results were categorized into four grades and the score was determined. To evaluate the extent of fibrosis, digital images were taken and analyzed by the point counting method

. The percentage of collagen deposits for each section was calculated. The collagen deposition rate was equal to the number of collagen (red) points in parenchyma divided by the total number of points in the lung parenchyma.

The inflammation score for tit anium dioxide at 3 days and 1 week after exposure was statistically higher than the control group. After one month no significant difference was observed between the titanium dioxide group and the control group. Titanium dioxide had similar scores to the c ontrol group for collagen deposition.

Acute Eye Irritation In a n acute eye irritation study ( Warheit, D., Hoke, R., Finlay, C. et al. 2007), uf

- C TiO 2 (80:20 ratio of anatase:rutile titanium dioxide; particle size ~0.140 μm) was evaluated for eye irritati on in New Zealand white rabbits. Approximately 57 mg of uf

- C TiO 2 was instilled into one eye of each animal. The eye remained unwashed. One animal was treated initially. No server irritation occurred, so an additional two rabbits were treated. The eyes wer e evaluated at 1, 24, 48 and 72 hours following instillation. The test material caused conjuctival redness (score 1 or 2) of all three rabbits. There was no corneal involvement as determined by fluorescent staining. The treated eyes were normal 24 or 48 ho urs after instillation.

Acute Dermal Irritation In an acute dermal irritation study ( Warheit, D., Hoke, R., Finlay, C. et al. 2007) uf

- C TiO 2 (80:20 ratio of anatase:rutile titanium dioxide; particle size ~0.140 μm) was evaluated for dermal irritation in new Zealand white rabbits. A single dose of 0.5 g uf

- C TiO 2 was applied to the shaved back after being moistened with 0.25mL of distilled wate r. The application area was covered with a 2

- ply gauze square held in place with non

- irritating tape and covered with porous tape (semi

- occlusive)., After the four hours expose period, the test substance was removed and the sites were evaluated by the Drai ze scoring system at 1, 24, 48 and 72 hours after removal. No skin irritation was observed during the study. Uf

- C TiO 2 was not a skin irritant under the conditions of this study.

Skin Sensitization In a skin sensitization study ( Warheit, D., Hoke, R., Finlay, C. et al. 2007) uf

- C TiO 2 (80:20 ratio of anatase:rutile titanium dioxide; particle size ~0.140 μm) was evaluated for dermal sensitization in the local lymph node assay in mice. Five groups of five female CBA/JHsd mice were dosed for three consecut ive days with 0% (vehicle), 5%, 25%, 50% or 100% titanium dioxide. A positive control (hexylcinnamaldehyde) group was also run. On the 5 th day of the study, 3H

- thymidine was injected into the tail vein of each mouse, and the mice11 were sacrificed 5 hours la ter. Cell proliferation in the draining auricular lymph nodes of the mice was evaluated. A stimulation index (SI) was derived for each group. A response was considered positive if the SI was ≥3.0. Stimulation indices of less than 3.0 were obtained for the titanium dioxide treated groups. The positive control produced the expected positive response. UF

- C TiO 2 was not a dermal sensitizer in the mouse local lymph node assay.

28

- Day Repeated Dose Oral Toxicity Study In a subchronic oral toxicity study (West, B. Wyzan, H., 1963), two groups of 10 male and 10 female rats were given 0 or 10 percent (approximately 100,000 ppm) N.F. grade TiO2 in their diet for 30

- 34 days. No treatment related effects were observed in this study.

90

- Day Oral Toxicity Study

- R at /M ouse (N CI study summarize results) In a N ational Cancer Institute (NCI ) 90

- day oral toxicity study on rats and mice, 10 males and 10 females of each species were administered titanium dioxide at doses of 6,250, 12,500, 25,000, 50,000, or 100,000 ppm. Te n males and 10 females of each species also received basal diets. In both studies, rats and mouse, 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 at doses up to 100,000 ppm (equal to 5000 mg/kg/day in rats)

.
In another three month subchronic toxicity study (Vernetti

- Blina, 1928), three groups of two dog s were given orally 0.05, 0.1 and 0.15 g of titanium dioxide. Every five days the dose was increased by the same amounts. One dog of each group was kept for one month, the other for two months. No toxic effects were seen in dogs.

A third, three month subc hronic toxicity study ( Bernard et al. 1990) was conducted on albino rats fed diets containing 0, 1.0, 3.16 and 10% titanium dioxide coated

- mica (TCM). No compound related effects on behavior, growth, food consumption or mortality were observed. Organs and tissues showed neither consistent gross changes nor histopathological changes that could be attributed to dietary administration of TCM.

Chronic Oral Toxicity Study

- Rat/Mouse (N CI study summarize results ) Groups of 50 rats of each sex and 50 mice of each s ex were administered titanium dioxide in the diet at one of two doses, either 25,000 or 50,000 ppm (approximately 1250 mg/kg/day and 2500 mg/kg/day respectively ) for 103 weeks. Matched controls consisted of 50 untreated rats of each sex and 50 untreated m ice 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 clinical12 sign that was judged to be related to the administration of titanium dio xide. Survival of the rats and male mice at the end of the bioassay was not affected by the test chemical; mortality in female mice was dose related

.
In another chronic oral toxicity study (Lehmann & Herget, 1927), two guinea

- pigs, two rabbits, two cats and one dog were fed technical grade titanium dioxide for 390 days. The dog received 9g/day, rabbits and cats, 3 g/day, and guinea pigs 0.6 g/day. No signs of systemic toxicity were observed in these animals.

Developmental Toxicity No study submitted.

R eproductive Toxicity (summary taken from MRID 48587801) In a nonguideline male reproductive parameter evaluation study (El

- Sharkawy, N., Hamza, S. and Abou

- Zeid, E. 2010), Male albino rats (180 to 200g; 6/group) were placed on diets containing 0, 1 and 2% titanium dioxide for a period of 65 days. Body weights were recorded at study initiation and at study termination. Clinical signs of toxicity were monitored. Serum levels of testosterone, nitrite, superoxide dismutase activity, glutathione reductase activi ty and malondialdehyde levels. The cauda epididymis was minced in saline and examined for sperm motility, sperm cell concentration, sperm abnormalities and live % spermatozoa. The testis, seminal vesicle and liver were fixed for histopathological examinati on.

At study termination various reproductive parameters were examined along with body weights and clinical signs of toxicity. Depression, anorexia and white feces were noted in the titanium dioxide treated groups (incidence not shown). Body weights were statistically significantly decreased in both treated groups compared to the control: 14.6% decrease at the low dose and 14% at the high dose. Sperm motility was depressed at both dosage levels but the decrease was statistically significant at the high dos e only. Sperm cell concentration, sperm viability and serum testosterone levels were statistically decreased and the number of sperm abnormalities were statistically increased at both titanium dioxide concentrations tested. Malondialdehyde levels were unaf fected by treatment; however, glutathione reductase and superoxide dismutase activities, and nitrite levels were statistically increased at both dosage levels compared to control levels.

Macroscopically, the seminal vesicles of the treated rats showed hyp ertrophy at the low dose and atrophy at the high dose. Microscopically, the lining of the seminal vesicle of all rats fed 1% titanium dioxide had hyperplastic changes with little or absence of secretion "beside edema of trabiculae" while at 2% titanium dio xide, there was a reduction in number and size of the epithelial cell lining of the tubuloaveolar glands. At the low dose, the seminiferous tubules revealed mild spermatogenesis with congested interstitial blood vessels with endotheliosis. Thickened tunica albuginea with degenerated spermatogonial cell layers and spermatocytes with the absence of spermatogenesis were also observed13 particularly at the high dose. Microscopic examination of the liver revealed hepatocytic degenerative changes which varied from vacuolar and hydropic degeneration to cell death at the low dose and increased in severity to mainly steatosis of the hepatic cells as the high dose. A NOAEL was not observed in this study. However a LOAEL was observed at 1% titanium dioxide in the diet wh ich is equivalent to approximately 500 mg/kg/day. However,
t h is male rate reproductive parameter study did not specify the particle size of the titanium dioxide used which may be micro or nano.

There was another open literature male mouse reproductive parameter study (Guo, LL. 2009) reported which was conducted with nano

- sized titanium dioxide that produced a LOAEL of 500 mg/kg /day and a NOAEL of 200 mg/kg /day based on decreases in the liver, heart and kidneys weights , and a significant increase in seru m biochemical parameters such as ALT, ALT/AST and BUN (P <0.05). The 500 mg/kg / day group also showed significantly reduced sperm density and motility, increased sperm abnormality and germ cell apoptosis but no obvious pathological changes in the liver, kid ney, spleen, testis and epididymis. Due to the similarities in toxicity between this these two reproductive parameter s tud ies , the male rat reproductive parameter study was likely also conducted with nano

- sized titanium dioxide and will not be used for ris k assessment purposes of microsized titanium dioxide

.
Genetic Toxicity (summary taken from MRID 48587801) In an In Vitro Sister Chromatid Exchange Assay and In Vitro Micronucleus Assay (Turkez, H. 2008), Titanium dioxide was tested for its potential to induce sister

- chromatid exchanges (SCE) and micronuclei formation in human whole blood cultures. Blood cultures were treated with 0, 1, 2, 3, 5, 7.5 or 10 uM titanium d ioxide. The formation of SCE and micronuclei were examined in the blood lymphocytes. SCE were increased in a dose

- related manner at titanium dioxide concentrations of 2 uM and above. Micronuclei were increased at titanium dioxide concentrations of 5 uM and above. When tested in the presence of either boric acid or borax, the titanium dioxide response was significantly reduced in both
assays.

In a DNA damage: formation of 8

- oxoguanine study (Rehn, B., Seiler, F., Rehn, S. et al 2002), female Wistar rats (5/group) were exposed by instillation to a single dose of 0.15, 0.3, 0.6, and 1.2 mg of titanium dioxide P25 (untreated, hydrophilic surface) or titanium dioxide T805 (silanized, hydrophobic surface) particles, suspended in 0.2 ml of physiological saline containing with 0.25% lecithin. The controls were instilled with the vehicle or with a single dose of 0.6 mg quartz DQ12 as a positive control. The rats were euthanized 90 days after instillation. Eight micron frozen sections of the left lobe of the lung stored at

- 80 degrees C. The sections were used for immunohistochemical detection of 8

- oxoguanine (8

- oxoGua) by a polyclonal antibody in the DNA of individual lung cells. The fluorescence intensity of 500 individual cells per animal was determined. The genotoxic effects in the lung of two types of commercially available titanium dioxide at low doses relevant to the working environment were examine d. Although, the companies supplying the titanium dioxide particles claimed14 their particle size was 20 nm, electron microscopy demonstrated that the particles were aggregated and agglomerated. Sonication was not successful in breaking up the particles to

a size of 20 nm. In the quartz

- exposed animals ninety days after exposure, a significant increase in the amount of 8

- oxoGua in the DNA of lung cells was detected. In contrast, animals exposed to TiO 2 P25 or TiO 2 T805 the amount of 8

- oxoGua as a marker of DN A damage, was at the level of the control.

In an In Vitro Micronucleus Assay and the Comet Assay (Falck, G., Lindberg, H., Suhonen, S. et al. 2009), various forms of titanium dio xide in human bronchial epithe lial BEAS 2B cells were tested using the Comet assay and the cytokinesis

- block micronucleus test. Rutile (nanosize) titanium dioxide stated to be 99.5% pure but found to contain <5% SiO 2 as a coating (particle size 10 x 40 nm), rutile (fine) titanium dioxide oxide (99.9% pure; particle size <5 jam) and anatase titanium dioxide nanopowder (99.7% pure; particle size <25 nm) were tested. Actual particle size was determined by transmission electron microscopy. Conce ntrations tested were 1 to 100 μg/cm 2 , which were selected based on preliminary cytotoxicity test. The Comet assay was conducted twice. The titanium dioxide forms were dispersed as agglomerates with an average size ranging from 3.8 pm (fine rutile) to 5.5 μ m (nanosized anatase) as determined by transmission electron microscopy. The dispersions als o contained nanosized particles. All three forms caused DNA damage in the Comet assay. Nanosized anatase and fine rutile showed similar induction of DNA damage. Nanosized rutile was less effective. However, none of the titanium dioxide forms produced a pot ent response. Only nanosized anatase induced micronuclei in BEAS 28B cells after 72 hours, but not at 24 and 48 hours. There was no dose response and there was only a doubling at the two doses that were positive for inducing micronuclei.

In an In Vitro Co met Assay (Karlsson, H., Gustafsson, J., Cronholm, P. et al. 2009), nano

- and microsized particles of titanium dioxide were used on human alveolar type

- II

- like epithelial cells (A594 cells). The ce lls were exposed to 40 and 80 μ g/ml of each particle size f or four hours. To measure DNA damage as single strand breaks and alkali labile sites, the alkaline version of the Comet assay was used. To investigate oxidative DNA lesions mainly oxidized purines, the FormamidoPyrimidine DNA Glycosylase enzyme was added. Thirty

- five cells in duplicate were analyzed. DNA damage was measured by as percent DNA in the tail. Particle size was determined to be an average of 63 nm for the nanosized tita nium dioxide particles and 1 μm for the microsized titanium dioxide particles. A significant increase in DNA damage was observed for both nano

- and microsized titanium dioxide particles at 80 μ g/mL . At 40
μ g/mL , both particle sized caused an increase in DNA damage; however, the increase was significant with the microsized titanium d ioxide particles, only.

In a Bacterial Reverse Mutation Test (Warheit, D., Hoke, R., Finlay, C. et al. 2007), Uf

- C TiO 2 (80:20 ratio of anatase.r utile titanium d ioxide; particle size ~0.140 μm ) was tested in the bacterial reverse mutation (Ames) test usin g the plate incorporation method. Titanium dioxide was tested in Salmonella tester strains TA98, TA100, TA1535 and TA1537 a nd15 Escherichia coli strain WP2 uvr A both in the presence and absence of metabolic activation (Arochlor induced rat liver). The vehicle was sterile water. Dosage levels tested wer e 100, 333, 1000, 333 and 5000 μ g/plate. The appropriate positive controls were used. Uf

- C TiO 2 did not produce a positive response in any of the test strains either in the presence or absence of metabolic activa tion.

In an In Vitro mammalian Chromosome Aberration Test (Warheit, D., Hoke, R., Finlay, C. et al. 2007), Uf

- C TiO 2 (80:20 ratio of anatase:rutile titanium d ioxide; particle size

- 0.140 μm ) was tested for chromosomal aberrations in vitro in Chinese hamster ovary cells in the presence and absence of metabolic activation (Aroclor

- induced rat liver S9). The vehicle was Milli

- Q water. Cytogenetic evaluations of structural aberrations and numerical aberrations were conducted in 200 cells in m etaphase at 7 50, 1250 and 2500 μg/mL for the 4 hour non activa ted test; at 62.5, 125 and 250 μg/mL for the 4 hour activated test; and at 25, 50 and 100 μg/mL for the 20 hour non

- activated test. The appropriate positive controls were included. Uf

- C TiO 2 did not produce structural or numerical aberrations under the conditions of this study.

Carcinogenicity In a bioassay of titanium dioxide performed by the National Cancer Institute (NCI 1979), groups of 50 rats of each sex and 50 mice of each sex were administered titani um dioxide in the diet at one of two doses, either 25,000 or 50,000 ppm (approximately 1,250 mg/kg/day and 2,500 mg/kg/day respectively), for 103 weeks and then observed for 1 additional week. A control group consisted of 50 untreated rats of each sex and 50 untreated mice of each

sex.

Administration of the titanium dioxide had no appreciable effect on the mean body weights of rats or mice of either sex. The only exception was the presence of white feces. No other clinical signs were observed to be relate d to the administration of titanium dioxide. In the female rats, C

- cell adenomas or carcinomas of the thyroid occurred at incidences that were dose related but were not high enough to be of significance. Therefore these tumors were not considered to be rel ated 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 was concluded that under the conditions of the bi oassay, titanium dioxide was not carcinogenic by the oral route for Fischer 344 rats or B6C3F1 mice.

( Summary taken from MRID 48587801) In a carcinogenicity study (IARC 2010), IARC summarized the available animal data on titanium dioxide as follows:16 Pigmentary and ultrafine titanium dioxide were tested for carcinogenicity by oral administration in mice and rats, by inhalation in rats and female mice, by intratracheal administration in hamsters and female rats and mice, by subcutaneous injection in rat s by intraperitoneal administration in male mice and female rats.

In one inhalation study, the incidence of benign and malignant lung tumours was increased in female rats. In another inhalation study, the incidences of lung adenomas were increased in the high

- dose groups of male and female rats. Cystic keratinizing lesions that were diagnosed as
squamous

- cell carcinomas but re

- evaluated as nonneoplastic pulmonary keratinizing cysts were also observed in the high

- dose groups of female rats. Two inhalation s tudies in rats and one in female mice were negative.

Intratracheally instilled female rats showed an increased incidence of both benign and malignant lung tumours following treatment with two types of titanium dioxide. Tumour incidence was not increased i n intratracheally instilled hamsters and female mice. Oral, subcutaneous and intraperitoneal administration did not produce a significant increase in the frequency of any type of tumour in mice or rats.

From these data, IARC concluded that there is suffic ient evidence in experimental animals for the carcinogenicity of titanium dioxide however there is inadequate evidence in humans for the carcinogenicity of titanium dioxide. The overall conclusion was that titanium dioxide is possibly carcinogenic to human s (Group 2B) based on the inhalation study (Heinrich et al. 1995)

. However IARC also states that titanium dioxide is a poorly soluble low toxicity (PSLT) particle, which can elicit overloading of lung clearance, chronic inflammation, and lung tumors in rat s following prolonged exposure at sufficiently high concentrations of particles. The tumors present in the lungs may have been a localized fibrogenic effect caused by overloading the lungs with titanium dioxide particles. IARC also concluded that titanium dioxide did not induce tumors by oral, intraperitoneal or subcutaneous routes of exposure in rats or mice

.
Dermal Absorption No dedicated study was submitted for dermal absorption but based on anecdotal findings in other submitted studies; it can be assumed that the titanium dioxide particles (non

nanosized) are too large to be absorbed through the skin. The World Health Organization (WHO) reported at the Joint FAO/WHO Expert Committee on Food Additives 1969 (JECFA 1969) that the compound is very inso luble and s howed no significant absorption.17 28

- Day Inhalation Toxicity (summary taken from MRID 48587801) In a 28

- day inhalation toxicity study (Warheit, D., Brock, W., Lee, K et al. 2005), twenty

- five male Chr:CD rats/group were exposed to one of six formulations of titanium dioxide for six hours per day, give days a week for a total of 20 exposures. A control group of 15 male rats were exposed to air only. Ten rats per group were subjected to a clinical laboratory evaluation (hematology, clinical chem istry and urinalysis) following the 20 th exposure and five/group subjected to a clinical laboratory evaluation after a 14 day recovery period. Urine aminolevulinic acid concentrations and blood aminolevulinic acid dehydrase activity were also determined. H istopathology was conducted on the organs/tissues of five rats/ group on the last day of exposure and at 14 days and three, six and 12 months after exposure. Weights of the heart, liver, lungs, spleen, testis and thymus were recorded. The exposure concentr ations were determined gravimetrically. The particle size (mass medium diameter) ranged from 1.3 to 1.8 μm among the size formulations. Bod y weight was reduced in the H

- 1 1,567 titanium dioxide formulation group but was similar to the control group's body w eight after the recovery period. No significant effects were observed with the other titanium dioxide formulations. The only notable clinical finding was lung noises in two rats (day 8 a nd 11, respectively) in the H

- 1 1,567 treated group; however, this find ing was absent by study day 15. Four mortalities occurred during the study: two in the

c ontrol group and one in the H

- 1 1,565 treated group and one in the H

- 1 1,566 treated group.

Neutrophils were si gnificantly elevated in the H

- 11,564 (high dose only), H

- 1 1,566, H

11,567, H

- 1 1,568 and H

- 1 1,569 treated groups. These values remained elevated after the 14

- day recovery period. No other significant findings were seen in the hematology, clinical chemistry and urinalysis parameters analyzed. Histological evaluatio n of the lungs of rats exposed to the titanium dioxide formulations had dust

- laden alveolar macrophages which is consistent with the elevation in the observed number of neutrophils (see discussion below).

The mean absolute and relative lung weights of rat s exposed to the six titanium dioxide formulations, except for the low dose H

- 1 1,565 group, were statistically elevated when compared to the control group. The lung weights remained elevated after the 4

- week recovery period through the 12 month recovery pe riod, except for the H

- 1 1,564 treated rats at both concentrations tested. The mean lung weight was still elevated at the high dose when compared to the control group.

At the end of the four

- week exposure period, the inhaled dust particles of all test grou ps were heavily concentrated with the bronchioles, alveolar ducts and alveoli. The dust particles were mostly phagocytized by the intra

- alveolar macrophages. In addition, dust cell accumulation and alveolar cell hyperplasia were obse rved in all rats expose d to H

- 1 1,564 at both test concentrations. A marked reduction in dust cells and alveolar cell proliferation was observed at the end of the 14 day and three month recovery periods; however, dust cells were still observed at the six and twelve month recovery periods.18 Rats exposed to H

- 11,567 and H

- 1 1,569 exhibited hyperplasia of the type II pneumocytes and disintegration of dust cells at the three month recovery period. The hyperplasia persisted to the 12 month recovery period. Light collagen deposition whic h represents a fibrogenic response was observed in the H

- 11,567 treated group. H

- 11,564, H

- 11,565, H

11,566, H

- 11,568 and H

- 1 1,569 exhibited slight alveolar cell hyperplasia at the end of the four week exposure. No effects on collagen deposition were obser ved.

The study author s concluded that except for H

- 1 1,567 which exhibited a slight fibrogenic response, the titanium dioxide formulations caused lung changes consistent with a nuisance dust.

90

- Day Inhalation Toxicity (summary taken from MRID 48587801) In a 90

- day inhalation toxicity study (Bermudez, E., Mangum, J., Wong, B. et al. 2004), the comparative toxicity of ultrafine titanium dioxide particles was examined in female B3C3F1/CrlBR mice, CDF (F344)/CrlBr rats and Lak:LVG (SYR)BR hamsters by inhalat ion exposure for 13 weeks, 6 hours/day, 5 days/week. Groups of 25 animals for each species and time point where used. The animals were sacrificed after 13 weeks of exposure and at 4, 13, 26 or 52 (49 for hamsters) after exposure had terminated. Dosage leve ls tested were 0, 0.5, 2 or 10 mg/m3. Lung burden of titanium dioxide was determined in the combined right lung lobes and in the lung

- associated lymph nodes. Left lung lobes were used to assess lung cell proliferation and histopathological end points. The inflammatory status of the lung was assessed at each time point using a separate group of animals subjected to bronchoalveolar lavage. Lavage fluid was assayed for lactate dehydrogenase and total protein and the differential cytology of recovered cells.

T he mass median aerodynamic diameter particle size was determined to be 1.29 μ m for hamsters, 1.45 μ m for mice and 1.44 μm for rats. Mean measured concentrations of titanium dioxide were 0.54, 2.2 and 10.8 mg/m 3 for mice, 0.52, 2.1 and 10.5 mg/m 3 for rats

a nd 0.53, 2.1 and 10.7 mg/m 3 for hamsters. Treatment related mortality was limited to mice (data not presented). The report states that body weight gain was depressed in mice and rats at the end of the exposure period and that body weight loss occurred in h amsters, but body weight data were not presented. Titanium dioxide burdens were equivalent at all exposure concentrations for rats and mice; however, lung burdens in hamsters were 2 to 5 fold lower than those of rats and mice. Lung burdens decreased in the lung with time in all three species and the decreases were dose dependent. Lymph node titanium dioxide burde n increased with time post expos ure.

Statistically significant changes in the cytological profile of the cells recovered by lavage were limited to the mice, rats and hamsters in the high

- dose group. Mice had significantly elevated numbers of macrophages, neutrophils and lymphocytes at the end of the exposure period which remained elevated until the 52 week recovery period. The same parameters

were s ignificantly affected in rats, but returned to normal at the 26 week recovery period.19 Only the percentage of neutrophils was increased in hamsters. Data were presented for the 10 mg/m 3 group. Total protein and LDH were unaffected in hamsters, but increases were observed in mice and rats at the high dose. Terminal bronchiolar cell replication was statistically increased at the end of the exposure period in mice (high dose), rats (mid and high dose) and hamsters (high dose). Values returned to control levels by week 4 post exposure in rats and mice and in hamsters by week 13. Alveolar cell replication was statistically increased in rats at the mid

- and high dose levels and returned to control levels at the 26 week post exposure period.

In rats, changes in the lungs at the low dose were restricted to the appearance of particles within alveolar macrophages and very minimal changes in the patterns of alveolar macrophage accumulation in the lungs. Lesions in the mid

- dose group were minimal to mild in severity and consisted primarily of particle

- laden macrophage accumulation and aggregation in subpleural regions and in centriacinar zones. These findings were associated with minimal hypertrophy and hyperplasia of type II alveolar epithelial cells. At the high dose in rats, there were progressively more severe epithelial proliferative changes, including metaplastic changes in the centriacinar region associated with particle burden. No lesions were seen in the low and mid

- dose mice. At the high dose, there was little ep ithelial change and the lesions consisted primarily of aggregations of heavily particle

- laden macrophages concentrated in centriacinar sites. Only alveolar and interstitial macrophages containing particles and occasional aggregation of particle

- laden macro phages at the high dose were seen in hamsters.

There were also treatment related mortalities. Four mice died during exposure phase of the study. Four more mice and seven rats died in post exposure phase. Hamsters had the greatest morbidity and mortality a t 35 in the post exposure phase but the authors believe this was due to age

- related conditions such as chronic renal disease. No control groups were used.

The study authors concluded that "[t]aken together, the species differences observed in this study reflect the outcome of previously reported chronic exposures to poorly soluble particulates for each species and suggest that susceptibility of the rat, unde r pulmonary overload conditions, to the induction of lung tumors by these materials has underlying components of dosimetry and biological response". The lowest NOAEL was 2.1 mg/m 3 found for rats. However due to the uncertainty and lack of data pertaining t o the effects which constituted the LOAEL, this study is not used for inhalation exposure risk assessment
purposes.

Subchronic, Reproductive and Genetic Toxicity S ummary

Table 3. Subchronic, Reproductive and Genetic Toxicity Data Summary.20 

## TOX PROFILE: Ti tanium Dioxide
Guideline No./Study Type Dose levels (ppm or

mg/kg bw/day) MRID No./Ref

. (year) * Results

870

- 3050 Repeated Dose 28

- Day Oral Toxicity Study in Rodents (non

guideline) 10% (100,000 ppm) TiO 2 for 30

- 34 days West, B. Wyzan, H. (1963) No treatment related effects were observed.

870

- 3100 90

- Day Oral Toxicity in Rats (non

- guideline) 0, 1.0, 3.16 & 10% TiO 2 for 90 days Bernard B.K. et al (1990) No compound related effects on behavior, growth,

food consumption or mortality were observed. Orga ns and tissues showed neither consistent gross changes nor histopathological changes that could be attributed to dietary abministration of titanium coated mica.
870

- 3150 90

- Day Oral Toxicity in Nonrodents (non

guideline) 0.05, 0.1 and 0.15g TiO 2 for 1 or 2 months (Dogs) Vernetti

- Blina (1928) No toxic effects were seen in dogs.

870

- 3100 90

- Day Oral Toxicity in rats/mice (non

guideline) 6,250, 12,500, 25,000, 50,000 or 100,000 ppm NCI Bioassay of

Titanium Dioxide (1979) No mortality and mean body weight gains similar to

controls. No gross or microscopic pathology was found pertaining to test chemical in rats or mice.

870

- 4100 Chronic Oral Toxicity in rats/mice (non

guideline) 25,000 or 50,000
ppm NCI Bioassay of Titanium Dioxide (1979) No evidence of toxicity based on growth rate,

mortality or other clinical signs for either dosed rats or mice after 104 weeks.

870

- 4100 Chronic Toxicity (non

guideline) 1 dog & 2 rabbits (9g/day), 2 cats (3g/day), 2 guinea pigs (0.6g/day) for 390 days Lehmann & Herget (1927) No signs of systemic toxicity were observed in these

animals.

870. 3800 Reproductive Toxicity in rats (non

guideline) 0, 1 and 2% TiO 2 for 65 days. (500mg/kg.day and 1000mg/kg/day) MRID 48587801 El

- Sharkawwy, N., Hamza, S., and Abou

- Zeid, E. (2010) The LOAEL was 1% titanium dioxide in the diet which is

approximately 500 mg/kg/day. This is 1/2 times the limit dose. Not clear on TiO 2 particle size, most likely nanosized.

870.4200 Carcinogenicity

– Oral (non

- guideline) 25,000 ppm and 5 0,000 ppm for 103 weeks. NCI Bioassay of Titanium Dioxide (1979) Titanium dioxide was not carcinogenic by the oral

route for Fischer 344 rats or B6C3F1 mice.

870.4200 Carcinogenicity

– Inhalation (non

guideline) Average of 10mg/m 3 for 2 years IARC (2010) Inadequate evidence in humans for the carcinogenicity of TiO 2 and there is sufficient evidence in experimental animals for the carcinogenicity of TiO 2 . TiO 2 is possibly carcinogenic to humans. 870.5000 In V

itro Sister Chromatid Exchange Assay/ In Vitro Micronucleus Assay (non

- guideline) 0, 1, 2, 3, 5, 7.5 or 10 μM. MRID 48587801 Turkez, H. (2008) Sister

- chromatid exchanges (SCE) were increased in a

dose

- related manner at conc. of 2 μM and above. Micronuclei were increase at TiO 2 conc. of 5 μM and above

.

870.5000 DNA Damage: Formation of 8

- Oxoguanine in
rats (non

- guideline) Single dose of 0.15, 0.3, 0.6, and 1.2 mg suspended in 0.2 mL of saline containing 0.25% lecithin. MRID 48587801 Rehn, B., Seiler, F., Rehn, S. et al. (2002) Animals exposed to TiO 2 showed no difference in the

amount of 8

- oxoGua than the control.

870.5375 In Vitro Micronucleus Assay and Comet Assay (non

- guideline) Rutile (nanosize), Rutile (fine) and Anatase nanopowder Conc. 1

- 100 μg/cm 2 MRID 48587801 Falck, G., Lindberg, H., Suhonen, S. et al. All three forms caused DNA damage in the Comet

assay. None produced a potent response. Only nanosized anatase induced micronuclei in BEAS 28B cells after 72 hours but not at 24 or 48 hours.21 (2009)
870.5 100 Bact erial Reverse Mutation Test (non

- guideline) 100, 333, 1000, 333 and 5000 μ/plate. MRID 48587801 Warheit, D., Hoke, R., Finlay, C. et al (2007) Uf

- C TiO 2 did not produce a positive response in any of

the test strains either in the presence or absence of
met abolic activation.

870.5375 In Vitro Mammalian Chromosome Aberration Test (non

guideline) 750, 1250 and 2500 μg/mL 4 hour non

activated test. 62.5, 125 and 250 μg/mL 4 hour active
test. 25, 50 and 100 μg/mL 20 hour non

activated test. MRID 48587801 Warheit, D., Hoke, R., Finlay, C. et al. (2007) Uf

- C TiO2 did not produce structural or numerical

aberrations under the conditions of the study.

870.3465 28

- Day Inhalation Toxicity in rats (non

- guideline) 85% to 99% TiO 2 MRID 48587801 Warheit, D., Brock, W., Lee, K et al. (2005) Except for rats exposed to 85%, which exhibited a

slight fibrogenic response, the TiO 2 formulations caused lung changes consistent with a nuisance dust.

870.3465 90

- Day Inhalation toxicity in rats, mice, hamsters (non

- guideline) 0, 0.5, 2 or 10 mg/m 3 MRID 48587801 Bermudez, E., Mangum, J., Wong, B. et al (2004) The LOAEL was assumed to be 2.1 mg/m 3 for rats.

However there are not enough details in the study on the effects to the animals to use this LOAEL for risk assessment purposes.

5.2 Toxicity Endpoint Selection The available toxicity studies on titanium dioxide via oral route of exposure clearly demonstrate lack of toxicity. The several studies in mice, rats, dogs, cats, rabbits and other species of varying durations do not indicate toxicity at very high doses (e.g. 50,000 ppm dietary exposure for two y ears in rats). No endpoint of concern via the oral route of exposure has been identified in the available database. Therefore, a dietary exposure
assessment was not conducted. This conclusion is in agreement with t he World Health Organization (WHO) Committ ee on Food Coloring Materials determin ation that no ADI need be set for the use of titanium dioxide based on the range of acute, sub

- acute and chronic toxicity assays, all showing low mammalian toxicity. Similarly, no significant toxicity of titanium diox ide is expected via the dermal route of exposure. All currently registered uses of titanium dioxide as an inert ingredient in lambda

- cyhalothrin, and all anticipated uses of titanium dioxide as an inert ingredient in napropamide formulations, do not inclu de residential applications. Therefore no residential risk assessment was performed. The available inhalation studies indicate that the primary toxicity of titanium dioxide is due to deposition of the inhaled particles and also suggest possible carcinoge nic effects due to prolong exposure. An occupational inhalation exposure assessment was not conducted based on the fact that the formulation type and use patterns of products that contain titanium dioxide do not result in direct exposure to titanium dioxi de particles by mixers , loaders and applicators of pesticides as well as post application (reentry) exposure ).22



### 6. EXPOSURE ASSESSMENT

Titanium dioxide is currently approved for use in a significant number of pharmaceutical, cosmetic, industrial and food prod ucts. Therefore, the potential for aggregate exposure from dietary and non

- dietary routes does exist for titanium dioxide. While it is difficult to develop a precise estimate of total human exposure to titanium dioxide, its low toxicity at relatively high doses indicate that expected exposures are likely to be of low toxicological

concern. The acute and chronic dietary (food and water) exposure assessments were not conducted because no endpoint of concern has been identi fied in the available database.

6.1 Cancer.

Carcinogenicity via Oral Route: Based on the National Cancer Institute (NCI) (1979) carcinogenicity study on male and female mice, tumors did not occur at incidences that were significantly higher than those for corresponding control groups when dosed at 25,000 or 50,000 ppm over 104 weeks via oral administration . However in female rats, C

- cell adenomas or carcinomas of the thyroid occurred at incidences that were dose related but were not high enough to meet the level required by the Bonferroni criterion. Thus, these tumors of the thyroid were not considered to be related to th e administration of the test chemical. They concluded that under the conditions of the bioassay, titanium dioxide was not carcinogenic by the oral route for Fischer 344 rat s or B6C3F1 mice.

The International Agency for Research on Cancer (IARC) review for titanium dioxide also concluded that oral, subcutaneous and intraperitoneal administration did not produce a significant increase in the frequency of any type of tumor in mice or rats.

An oral cancer risk assessment for titanium dioxide was not performed based on the results of carcinogenicity studies in mice and rats, and conclusions by the IARC.

Carcinogenicity via Inhalation Route: The IARC review on titanium dioxide concluded that there may be s ome evidence of carcinogenicity via inhalation however these effects may be attributable to overloading of lung clearance and chronic inflammation following prolonged exposure at high particle concentrations of titanium dioxid e

.
Occupational exposure to titanium dioxide may occur via the inhalation route; however any concern for carcinogenic it y is addressed by health

- protective exposure levels established by under the Occupational Safety and Health Administration’s (OSHA) Permissible Exposure Limit (PEL ) for titanium dioxide

. OSHA does not regulate titanium dioxide as a carcinogen . The OSHA permissible exposure limit for titanium dioxide is 15 mg/m 3 , as total dust, expressed as an 8

- hour time

- weighted average. These23 concentration levels far exceed actual expected occupational exposure concentrations of titanium dioxide n pesticide formulations Therefore, an inhalation cancer risk assessment for occupational exposure was not conducted and there are no occupational risk s of concern



### 7. RESIDENTIAL EXPOSURE/RISK PATHWAY

Based on the use patterns of products that would contain 5% titanium dioxide by weight in pesticide formulations containing the active ingredient napropamide, there are no uses that would be applied in and/or around the home or in a way which would results in residential
exposures , therefore a residential exposure risk assessment is not required and there are no residential risks of concern

.



### 8. AGGREGATE RISK AND DETERMINATION OF SAFETY

In examining aggregate e xposure, FFDCA section 408 directs EPA to consider available information concerning exposures from the pesticide residue in food and all other non

occupational exposures, including drinking water from ground water or surface water and exposure through pest icide use in gardens, lawns, or buildings (residential and other indoor uses). FFDCA section 408 provides that EPA shall also apply an additional tenfold margin of safety for infants and children in the case of threshold effects in calculating a dose leve l that to account for pre

- and post

- natal toxicity and the completeness of the database unless EPA determines that a different margin of safety will be safe for infants and children. Margins of safety are incorporated into EPA risk assessments either direc tly through the use of margin of exposure analysis or through using uncertainty (safety) in calculating a dose level that poses no appreciable risk to humans.

Titanium dioxide has two exemptions from the requirement of a tolerance:, 40 CFR § 180.920 pesticide formulations applied to growing crops and 40 CFR § 180.930 pesticide formulations applied to animals. Titanium dioxide is also approved for use as a colorant in food (21 CFR § 73.575), in drugs (21 CFR § 73.1575), and in cosmetics (21 CFR § 73.25 75; 21 CFR § 73.3126). There has also been a previous exemption from requirement of a tolerance for residues in or on growing crops, when used as an inert ingredient (UV protectant) in microencapsulated formulations of the insecticide lambda

- cyhalothrin at no more than 3.0% by weight or the formulations (40 CFR § 180.1195).

8.1 Acute Aggregate Risk24 There was no hazard attributable to a single exposure seen in the toxicity database for titanium dioxide; therefore, an acute aggregate risk assessment is not requ ired.

8.2 Short

- Term/Intermediate

- Term Aggregate Risk

The short

- term and intermediate

- term aggregate risk includes chronic dietary exposures to food and drinking water and short

- or intermediate

- term residential exposures. There are currently no active registrations for titanium dioxide as used under the existing and proposed tolerance exemptions that may result in residential exposures

. C hronic dietary risk was not assessed due to the absence of any hazards identified in t he toxicity database

. Therefore short

- term and Intermediate

- term aggregate risks for titanium dioxide are considered not of concern.

8.3 Long

- Term Aggregate Risk

The long

- term aggregate risk includes chronic dietary exposures to food and drinking water only . There are currently no active registrations for titanium dioxide as used under the existing and proposed tolerance exemptions that may result in residential
exposures . Chronic dietary risk was not assessed due to the absence of any hazards identified in the toxicity database

. Therefore, l ong

- t erm (chronic) aggregate risks for titanium dioxide are not expected to be of concern.



### 9. OCCUPATIONAL EXPOSURE/RISK PATHWAY

The Agency has considered uses of products that would contain titanium dioxide at 5% of formulation with napropamide and has determined that there may be a concern for occupational exposure.

9.1 Handler Risk

O ccupational dermal and inhalation exposure is expected to be low because of personal protective equipment requirements associated with the use of pesticide products
cont aining napropamide and lambda

- cy halothrin

. However due to the classification of titanium dioxide as possibly carcinogenic to hu mans by IARC , there is a potential concern for cancer risk via inhalation exposure by workers. H owever, worker inhalation exposures to titanium dioxide , based on the considered uses of products that would contain titanium dioxide at 5% in napropamide formulations , are orders of magnitude less than levels associated with increased tumor incidence in animal studies and as well as occupational exposure levels allowed by the Occupational Safety and Health25 Administration (OSHA) or The American Conference of Governmenta l Industrial Hygienists (ACGIH)

. The OS H A Permissible Exposure Limit (PEL) for General I ndustry (29 CFR 1910.1000) is set to 15 mg/m 3 TWA. The ACGIH Threshold Limit Value (TLV) is 10 mg/m 3 TWA and OSHA does not classify titanium dioxide as a human carcinogen.

9.2 Occupational Post Application Risk

Inhalation exposures are not typically considered for occupational post

- application scenarios because inhalation exposures generally account for a negligible percentage of the overall body burden for most pesticide chemicals. Therefore occupational post application exposure is not expected to b e of concern.



### 10. CUMULATIVE EXPOSURE

Cumulative effects from substances with a common mechanism of toxicity, Section 408(b)(2)(D)(v) of Federal Food, Drug and Cosmetic Act ( FFDCA ) requires that, when considering whether to establish, modify, or revoke a tolerance, the Agency consider “available information” concerning the cumulative effects of a particular pesticide’s residues and “other substances that have a common mechanism of t oxicity.”

EPA has not found a common mechanism of toxicity with any other substances. Titanium dioxide for the purposes of this tolerance action is assumed to not have a common mechanism of toxicity with other substances. For information regarding EPA’s e fforts to determine which chemicals have a common mechanism of toxicity and to evaluate the cumulative effects of such chemicals, see EPA’s website at http://www.epa.gov/pesticides/cumulative

.



### 11. ENVIRON MENTAL FATE CONSIDERATIONS

Titanium dioxide is a stable inorganic compound that is insoluble in water. Titanium dioxide is naturally occurring and is found in both sediments and soils. Titanium dioxide is a solid at environmentally relevant temperatures a nd pressures and is therefore not expected to volatilize into the atmosphere.



### 12. ECOTOXICITY

In an acute toxicity to freshwater fish study ( Warheit, D., Hoke, R., Finlay, C. et al. 2007 ), fine (99% titanium dioxide and 1% alumina; particle size ~0.380 μm) a nd ultrafine titanium dioxide (90% titanium dioxide, 7% alumina and 1% amorphous silica; 80:20 ratio of26 anatase:rutile; particle size 0.140 μm) was determined in rainbow trout ( Oncorhynchus mykiss ). There was no mortality in the test at the end of 96 hours . The 96 hour LC 50 for both titanium dioxide test materials was > 100 mg/L. Titanium dioxide is considered practically nontoxic to freshwater fish on acute bases.

In an acute toxicity to freshwater invertebrate study ( Warheit, D., Hoke, R., Finlay, C. et al. 2007 ), fine (99% titanium dioxide and 1% alumina; particle size ~0.380 μm) and ultrafine titanium dioxide (90% titanium dioxide, 7% alumina and 1% amorphous silica; 80:20 ratio of anatase:rutile; particle size 0.140 μm) was determined in Daphnia magna under static, unaerated test conditions. The 48 hour EC 50 based on nominal concentrations for both titanium dioxide test materials was > 100 mg/L. Titanium dioxide is considered practically nontoxic to freshwater invertebrates on acute bases.

In an acute toxicity to green algae study ( Warheit, D., Hoke, R., Finlay, C. et al. 2007 ), fine (99% titanium dioxide and 1% alumina; particle size ~0.380 μm) and ultrafine titanium dioxide (90% titanium dioxide, 7% alumina and 1% amorphous silica; 80:20 ratio of
anat ase:rutile; particle size 0.140 μm) was determined in green algae species Pseudokirchneriella subcapitata static test conditions. The algae 72 hour EC 50 values (95% fiducial limits) based on inhibition of growth and healthy cell counts were 16 (12

- 22) mg/L for fine titanium dioxide particles and 21 (16

- 26) mg/L for ultrafine particles. The 72 hours EC 50 values (95% fiducial limits) for growth rate based on nominal concentrations and healthy cell counts were 61 (52

- 72) mg/L for fine particles and 87 (83

- 91) mg/L for ultrafine particles.

Based on the 2005 FQPA reassessment of titanium dioxide, there was an acute aquatic toxicity study available from 2002 ECOTOX database. The one cited was a fathead minnow study which produced a LC 50 > 1000 mg/L which supports the conclusion that titanium dioxide is practically nontoxic to freshwater fish on an acute bases.

Based on the three studies submitted for acute fish toxicity, acute invertebrate toxicity and algal toxicity titanium dioxide and the study cited form the 2005 FQPA reassessment, titanium dioxide may be classified as practically non

- toxic to aquatic organisms

. Based on the insoluble nature of titanium dioxide in water and the low acute toxicity of titanium dioxide to freshwater fish, there are no non

- targe t aquatic species risk concerns resulting from the use of titanium dioxide as an inert ingredient. Based on the lack of absorption data that was identified in the toxicological effects in the animal testing, there are very low risks for non

- target terrestr ial organisms resulting from the use of titanium dioxide being used as an inert ingredient.



### 13. ENVIRONMENTAL JUSTICE STATEMENT27 Potential areas of environmental justice concerns, to the extent possible, were considered in this human health risk assessment, i n accordance with U.S. Executive Order 12898, "Federal Actions to Address Environmental Justice in Minority Populations and Low

- Income Populations," ( http://www.eh.doe.gov/oepa/guidance/justice/eo12898.pdf ).

As a part of every pesticide risk assessment, OPP considers a large variety of consumer subgroups according to well

- established procedures. In line with OPP policy, IIAB estimates risks to population subgroups from pesticide exposures that are based on pa tterns of that subgroup’s food and water consumption, and activities in and around the home that involve pesticide use in a residential setting. Extensive data on food consumption patterns are compiled by the USDA under the Continuing Survey of Food Intak e by Individuals (CSFII) and are used in pesticide risk assessments for all registered food uses of a pesticide. These data are analyzed and categorized by subgroups based on age, season of the year, ethnic group, and region of the country. Additionally, OPP is able to assess dietary exposure to smaller, specialized subgroups and exposure assessments are performed when conditions or circumstances warrant. Whenever appropriate, non

- dietary exposures based on home use of pesticide products and associated r isks for adult applicators and for toddlers, youths, and adults entering or playing on treated areas post application are evaluated. Further considerations are currently in development as OPP has committed resources and expertise to the development of spe cialized software and models that consider exposure to bystanders and farm workers as well as lifestyle and traditional dietary patterns among specific subgroups.



### 14. RISK CHARACTERIZATION

The petitioner, United Phosphorus Inc., submitted a request (Petition # 1E7918) to the EPA for an amendment of an existing tolerance exemption for the food use inert ingredient, titanium dioxide (CAS Reg. No. 13463

- 67

- 7) when used as a pesticide in or on growing crops as an inert ingredient (UV protectant) in microencapsulated formulations of the insecticide lambda

- cyhalothrin at no more than 3.0% by weight of the formulation (40 CFR § 180.1195 to include the use of titanium dioxide as an inert ingredient (UV

- stabilizer) at no more than 5% in napropamide pestic ide formulations. The acute toxicity of titanium dioxide is very minimal. There were no acute toxicological end points of concern identified in the acute toxicity database. Subchronic and chronic oral toxicity studies performed on rats and mice up to 50,0 00 ppm and over 2 years showed no toxicity. There were no guideline reproductive or developmental studies submitted or in the database. Genotoxicity results were mixed and inconclusive. It was concluded that titanium dioxide was not carcinogenic via the or al route however there are concerns via inhalation. The tumors present in the lungs may have been a localized fibrogenic effect caused by overloading the lungs with high concentrations of titanium dioxide particles over a prolonged period. IARC also conclu ded28 that titanium dioxide did not induce tumors by oral, intraperitoneal or subcutaneous routes of exposure in rats or mice

. The acute and chronic dietary (food and water) exposure assessments were not conducted because no endpoint of concern has been iden tified in the available database. Based on the use products that would contain 5% titanium dioxide by weight in pesticide formulations containing the active ingredient napropamide, there are no uses that would be applied in and/or around the home or in a w ay which would results in residential exposures , therefore a residential exposure risk assessment is not required and there are no residential risks of

concern

. There was also no aggregate risk assessments performed since there was no single
exposure , diet ary or drinking water endpoints of concern. Titanium dioxide is a stable inorganic compound that is insoluble in water. Titanium dioxide is a solid at environmentally relevant temperatures and pressures and is therefore not expected to volatilize into the atmosphere. Based on the insoluble nature of titanium dioxide in water and the low acute toxicity of titanium dioxide to freshwater fish, there are no non

- target aquatic species risk concerns resulting from the use of titanium dioxide as an inert ingredien t. Based on the lack of absorption data that was identified in the toxicological effects in the animal testing, there are very low risks for non

- target terrestrial organisms resulting from the use of titanium dioxide being used as an inert ingredient.

Tak ing into consideration all available information on titanium dioxide, EPA concludes that there is a reasonable certainty that no harm will result to the general population when titanium dioxide is used as an inert ingredient. The establishment of an exempt ion from tolerance for food use for residues of titanium dioxide when used as an inert ingredient (UV protectant) applied to growing crops in pesticide formulations containing the active ingredient napropamide at no more than 5.0% by weight of the formulat ion can be considered safe under section 408 of the FFDCA. This approval granted only for the use of micronized form of titanium dioxide and nano sized is prohibited.



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