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9-19-2012 

Provisional Peer-Reviewed Toxicity Values for 

Thallium and Compounds

Metallic Thallium (7440-28-0), Thallium (I) acetate (563-68-8), 

Thallium (I) carbonate (6533-73-9), Thallium (I) chloride (7791-12-0), 

Thallium (I) nitrate (10102-45-1), and Thallium (I) sulfate (7446-18-6)

Superfund Health Risk Technical Support Center

National Center for Environmental Assessment

Office of Research and Development

U.S. Environmental Protection Agency

Cincinnati, OH 45268
i Thallium and Compounds 

AUTHORS, CONTRIBUTORS, AND REVIEWERS

CHEMICAL MANAGER

Nina Ching Y. Wang, PhD 

National Center for Environmental Assessment, Cincinnati, OH

DRAFT DOCUMENT PREPARED BY 

ICF International

9300 Lee Highway 

Fairfax, VA 22031 

PRIMARY INTERNAL REVIEWERS

Ambuja Bale, PhD, DABT 

National Center for Environmental Assessment, Washington, DC 

Ghazi Dannan, PhD 

National Center for Environmental Assessment, Washington, DC 

Paul G. Reinhart, PhD, DABT 

National Center for Environmental Assessment, Research Triangle Park, NC

Questions regarding the contents of this document may be directed to the U.S. EPA Office of 

Research and Development’s National Center for Environmental Assessment, Superfund Health 

Risk Technical Support Center (513-569-7300) 
ii Thallium and Compounds 

TABLE OF CONTENTS

COMMONLY USED ABBREVIATIONS ................................................................................... iii

BACKGROUND .............................................................................................................................1

HISTORY ....................................................................................................................................1

DISCLAIMERS ...........................................................................................................................2

QUESTIONS REGARDING PPRTVS .......................................................................................2

INTRODUCTION ...........................................................................................................................2

REVIEW OF POTENTIALLY RELEVANT DATA (CANCER AND NONCANCER) ..............3

HUMAN AND ANIMAL STUDIES ........................................................................................10

Carcinogenicity Studies ........................................................................................................ 10

Inhalation Exposures ............................................................................................................. 10

DERIVATION OF PROVISIONAL VALUES ............................................................................10

DERIVATION OF PROVISIONAL ORAL REFERENCE DOSES ........................................10

DERIVATION OF INHALATION REFERENCE CONCENTRATIONS ..............................11

CANCER WEIGHT-OF-EVIDENCE DESCRIPTOR .............................................................11

DERIVATION OF PROVISIONAL CANCER POTENCY VALUES ....................................11

APPENDIX A. PROVISIONAL SCREENING VALUES ..........................................................12

APPENDIX B. DATA TABLES ..................................................................................................17

APPENDIX C. REFERENCES ....................................................................................................20
iii Thallium and Compounds 

COMMONLY USED ABBREVIATIONS

BMC Benchmark Concentration

BMD Benchmark Dose 

BMCL Benchmark Concentration Lower bound 95% confidence interval

BMDL Benchmark Dose Lower bound 95% confidence interval 

HEC Human Equivalent Concentration 

HED Human Equivalent Dose 

IRIS Integrated Risk Information System 

IUR inhalation unit risk

LOAEL lowest-observed-adverse-effect level

LOAELADJ LOAEL adjusted to continuous exposure duration 

LOAELHEC LOAEL adjusted for dosimetric differences across species to a human

NOAEL no-observed-adverse-effect level

NOAELADJ NOAEL adjusted to continuous exposure duration 

NOAELHEC NOAEL adjusted for dosimetric differences across species to a human

NOEL no-observed-effect level

OSF oral slope factor 

p-IUR provisional inhalation unit risk 

p-OSF provisional oral slope factor 

p-RfC provisional reference concentration (inhalation) 

p-RfD provisional reference dose (oral) 

POD point of departure (oral) 

RfC reference concentration (inhalation)

RfD reference dose 

UF uncertainty factor

UFA animal to human uncertainty factor 

UFC composite uncertainty factor 

UFD incomplete to complete database uncertainty factor

UFH interhuman uncertainty factor

UFL LOAEL to NOAEL uncertainty factor

UFS subchronic to chronic uncertainty factor 

WOE weight of evidence 
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1 Thallium and Compounds 

PROVISIONAL PEER-REVIEWED TOXICITY VALUES FOR THALLIUM AND 

COMPOUNDS: METALLIC THALLIUM (7440-28-0), 

THALLIUM (I) ACETATE (563-68-8), THALLIUM (I) CARBONATE (6533-73-9), 

THALLIUM (I) CHLORIDE (7791-12-0), THALLIUM (I) NITRATE (10102-45-1), 

THALLIUM (I) OXIDE (1314-12-1), THALLIUM (III) OXIDE (1314-32-5), 

THALLIUM (I) SELENITE (12039-52-0), AND THALLIUM (I) SULFATE (7446-18-6) 

BACKGROUND

HISTORY

On December 5, 2003, the U.S. Environmental Protection Agency’s (EPA) Office of 

Superfund Remediation and Technology Innovation (OSRTI) revised its hierarchy of human 

health toxicity values for Superfund risk assessments, establishing the following three tiers as the 

new hierarchy:

1) EPA’s Integrated Risk Information System (IRIS). 

2) Provisional Peer-Reviewed Toxicity Values (PPRTVs) used in EPA’s Superfund 

Program.

3) Other (peer-reviewed) toxicity values, including 

 Minimal Risk Levels produced by the Agency for Toxic Substances and Disease 

Registry (ATSDR),

 California Environmental Protection Agency (CalEPA) values, and 

 EPA Health Effects Assessment Summary Table (HEAST) values.

A PPRTV is defined as a toxicity value derived for use in the Superfund Program when 

such a value is not available in EPA’s IRIS. PPRTVs are developed according to a Standard 

Operating Procedure (SOP) and are derived after a review of the relevant scientific literature 

using the same methods, sources of data, and Agency guidance for value derivation generally 

used by the EPA IRIS Program. 

This PPRTV assessment was developed using only information provided in the 

Toxicological Review of Thallium and Compounds (CAS No. 7440-28-0) (U.S. EPA, 2009). All 

of the information provided in this document was available to peer reviewers according to the 

standard IRIS peer review process. 

No toxicity values were posted on the IRIS database (U.S. EPA, 2009) for thallium 

because of limitations in the database of toxicological information. However, the Toxicological 

Review presents information which could be used for development of an RfD. In this document, 

an appendix with a “screening subchronic and chronic p-RfD” is provided, recognizing the 

quality decrements, which may be of value under certain circumstances, described later in this 

document. 

Because new information becomes available and scientific methods improve over time, 

PPRTVs are reviewed on a 5-year basis and updated into the active database. Once an IRIS 

value for a specific chemical becomes available for Agency review, the analogous PPRTV for 

that same chemical is retired. It should also be noted that some PPRTV documents conclude that 

a PPRTV cannot be derived based on inadequate data.
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2 Thallium and Compounds 

DISCLAIMERS

Users of this document should first check to see if any IRIS values exist for the chemical 

of concern before proceeding to use a PPRTV. If no IRIS value is available, staff in the regional 

Superfund and Resource Conservation and Recovery Act (RCRA) program offices are advised to 

carefully review the information provided in this document to ensure that the PPRTVs used are 

appropriate for the types of exposures and circumstances at the Superfund site or RCRA facility 

in question. PPRTVs are periodically updated; therefore, users should ensure that the values 

contained in the PPRTV are current at the time of use. 

It is important to remember that a provisional value alone tells very little about the 

adverse effects of a chemical or the quality of evidence on which the value is based. Therefore, 

users are strongly encouraged to read the entire PPRTV document and understand the strengths 

and limitations of the derived provisional values. PPRTVs are developed by the EPA Office of 

Research and Development’s National Center for Environmental Assessment, Superfund Health 

Risk Technical Support Center for OSRTI. Other EPA programs or external parties who may 

choose of their own initiative to use these PPRTVs are advised that Superfund resources will not 

generally be used to respond to challenges of PPRTVs used in a context outside of the Superfund 

Program.

QUESTIONS REGARDING PPRTVS

Questions regarding the contents of the PPRTVs and their appropriate use (e.g., on 

chemicals not covered, or whether chemicals have pending IRIS toxicity values) may be directed 

to the EPA Office of Research and Development’s National Center for Environmental 

Assessment, Superfund Health Risk Technical Support Center (513-569-7300), or OSRTI. 

INTRODUCTION

An IRIS Toxicological Review of Thallium and Compounds was previously developed 

and posted (http://www.epa.gov/iris/toxreviews/1012tr.pdf). However, due to study and data 

quality limitations as stated in the IRIS Toxicological Review, an RfD was not derived. 

Although these limitations precluded the derivation of an RfD, there are dose-response data that 

may be used in the derivation of screening subchronic and chronic p-RfDs (see Appendix A). 

This PPRTV for Thallium and Compounds is based mostly on the IRIS Toxicological Review; 

all relevant text and tables were either reproduced or adapted from the IRIS Toxicological 

Review.

Metallic thallium (Tl) is insoluble in water; however, the majority of the thallium salts 

are soluble in water with the exception of thallium (III) oxide. Thallium compounds and their 

chemical and physical properties are listed in Table 1. Thallium occurs naturally in the earth’s 

crust. It is used in industry, but is also released due to combustion of fossil fuels, refinement of 

oil fractions, smelting of ores, and by some other industrial processes such as cement production 

and brickworks (Kazantzis, 2007; IPCS, 1996). A summary of past uses and possible health 

effects of thallium (I) sulfate as cited in the IRIS Toxicological Review is provided as follows: 
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3 Thallium and Compounds 

Due to its ability to remove hair, thallium (I) sulfate was used in the past 

as a depilatory agent. Thallium (I) sulfate was once used in medicine to treat 

infections, such as venereal diseases, ringworm of the scalp, typhus, tuberculosis, 

and malaria. It was also used in the past as a pesticide for various rodents and 

insects but has been banned for this use in the U.S. since 1972. Currently, 

thallium is used in the semiconductor industry and the manufacture of optic 

lenses. When thallium is alloyed with mercury, it is used on switches and 

closures, which can operate at subzero temperatures. Thallium compounds are 

also used to manufacture low-melting glass, low-temperature thermometers, 

alloys, electronic devices, mercury lamps, fireworks, and imitation gems. 

Thallium radioisotopes are used in medicine for scintigraphy of certain tissues 

and the diagnosis of melanoma (Ibrahim et al., 2006; National Library of 

Medicine [NLM], 1998; IPCS, 1996; Agency for Toxic Substance and Disease 

Registry [ATSDR], 1992; U.S. EPA, 1991). 

Table 1. Chemical and Physical Properties of Thallium 

and Selected Thallium Compoundsa 

Name CASRN

Chemical

Formula

Molecular

Weight

Melting Point

(°C)

Boiling Point

(°C)

Solubility in Water 

(g/L)

Metallic thallium 7440-28-0 Tl 204.38 303.5 1457 Insoluble 

Thallium (I) acetate 563-68-8 TlC2H3O2 263.43 131 No data Very soluble 

Thallium (I) carbonate 6533-73-9 Tl2CO3 468.78 273 No data 40.3 (15.5°C) 

Thallium (I) chloride 7791-12-0 TlCl 239.84 430 720 Very soluble (20°C)

Thallium (I) nitrate 10102-45-1 TlNO3 266.39 206 430 95.5 (20°C) 

Thallium (I) oxide 1314-12-1 Tl2O 424.77 596 No data Soluble 

(as TlOH) 

Thallium (III) oxide 1314-32-5 Tl2O3 456.76 717 875 Insoluble 

Thallium (I) selenite 12039-52-0 Tl2SeO3 535.72 No data No data No data 

Thallium (I) sulfate 7446-18-6 Tl2SO4 504.82 632 Decomposes 48.7 (20°C) 

a

Sources: IPCS (1996); Downs (1993); ATSDR (1992). Table was obtained directly from Table 2-1 in U.S. EPA (2009). 

REVIEW OF POTENTIALLY RELEVANT DATA 

(CANCER AND NONCANCER)

Table 2 provides a summary of studies of thallium toxicity in humans. Table 3 provides 

a summary of oral toxicity studies of thallium (and compounds) in animals. No inhalation 

studies in animals or human were identified. A literature search through May 2009 was 

conducted in support of the IRIS Toxicological Review of Thallium and Compounds (U.S. EPA, 

2009); an updated literature search was not conducted in developing the PPRTV for Thallium

and Compounds. All pertinent data on thallium and related compounds have been reviewed by 

IRIS, and a Toxicological Review is available (U.S. EPA, 2009). Tables 2 and 3 are adapted 

from the Toxicological Review with minor clarifications (U.S. EPA (2009), Tables 4-1 and 4-5, 

respectively). 
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4 Thallium and Compounds 

Table 2. Thallium Toxicity In Humans Following Oral Exposure 

Reference Sex Age Dose Symptomsa Final Outcome

Males-Adult

Gefel et al. 

(1970) 

Male 41 years Unknown but chronic; 

urine thallium 

0.15 mg/100 mL

High blood pressure; lower back pain; vomiting; severe pain in the feet; 

weakness of the calf muscle; alopecia; slurred speech; atrophic lower limbs; 

limited vision

Death

Cavanagh 

et al. (1974) 

Male 60 years 0.93 g thallium (I) 

acetate in 2 divided 

doses

Diarrhea; vomiting; dizziness; back pain; paresthesia of the feet and lower legs; 

high blood pressure; facial weakness; dysphagia; difficulty breathing

Death within a week of 

symptoms

Cavanagh 

et al. (1974) 

Male 56 years 0.93 g thallium (I) 

acetate in 3 divided 

doses

Abdominal pain; diarrhea; vomiting; paresthesia; photophobia, nystagmus, 

visual impairment; facial weakness; bilateral ptosis

Death within 3 weeks of 

symptoms

Cavanagh 

et al. (1974) 

Male 26 years 0.31 g thallium (I) 

acetate

Paresthesia in both feet; chest pain; tenderness over the sternum; vomiting, 

weakness, pain in the knees and ankles that inhibited walking; alopecia

Recovery

Davis et al. 

(1981)

Male 19 years 5–10 g thallium (I) 

nitrate

Nausea; vomiting; slurred speech; paresthesia of hands and feet; respiratory 

weakness

Death

Limos et al. 

(1982) 

Male 56 years Unknown Visual disturbances; alopecia; elevated aspartate aminotransferase (AST) and 

alanine aminotransferase (ALT); high blood glucose and creatine kinase; 

decreased myelinated fibers; denervated Schwann cell clusters

Bedridden; could not speak

Limos et al. 

(1982) 

Male 26 years Unknown Visual disturbances; alopecia; elevated AST and ALT; high blood glucose and 

creatine kinase; decreased myelinated fibers; denervated Schwann cell clusters

Residual tremors of the 

extremities and muscle 

weakness of the lower 

limbs

Roby et al. 

(1984) 

Male 45 years Unknown; urine 

thallium: 

2000 μg/L

Burning pain in feet; inability to walk; alopecia; acute fibrillation Continued neurological 

dysfunction

Heyl and 

Barlow 

(1989) 

Male “Five 

young 

men”

Unknown Follicular plugging of the skin (nose, cheeks, and nasolabial folds) by keratinous 

material; crusted eczematous lesions and acneiform eruptions on the face; dry 

scaling on palms and soles; and alopecia (scalp, eyelashes, lateral eyebrows, 

arms, and legs). Skin biopsies (scalp and cheek): disintegrating hair shafts, gross 

follicular plugging, and eosinophilic keratohyalin granules in the epidermis; 

necrotic sebaceous glands; pustular lesions on the face: folliculitis and necrosis 

of the follicles; (feet) marked hyperkeratosis and hypergranulosis

4/5 recovered; 1/5 

experienced permanent 

neurological damage
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5 Thallium and Compounds 

Table 2. Thallium Toxicity In Humans Following Oral Exposure 

Reference Sex Age Dose Symptomsa Final Outcome

Yokoyama 

et al. (1990) 

Male 31 years Unknown; urine 

thallium: 

3.5 mg/L

Nausea, vomiting; leg pain; alopecia; abnormal behavior; decreased conduction 

velocity of fast nerve fibers

Recovery

Hantson et 

al. (1997)

Male 48 years 200 mg thallium (I) 

sulfate

No overt symptoms within 24 hours; increase in binucleated cells with 

micronuclei 15 days after exposure

Recovery

Hirata et al. 

(1998) 

Male 29 years Unknown; hair 

thallium: 20 ng/g 

(32 months after 

possible exposure)

Alopecia; abdominal pain; diarrhea; tingling in extremities; neuropathy Recovery

Atsmon et 

al. (2000) 

Male 40 years Unknown; urine 

thallium: 7 mg

Weakness of the limbs; vomiting; severe neurological symptoms; alopecia; high 

blood pressure; increased ALT and AST; Mees lines; decreased visual acuity; 

bilateral foot drop

Recovery

Sharma et 

al. (2004) 

Male 48 years Unknown; serum 

thallium: 

870 μg/100 mL urine 

thallium: 5000 μg/mL

Painful peripheral neuropathy; decreased consciousness Death

Females-Adult

Roby et al. 

(1984) 

Female 51 years Unknown; serum 

thallium: 

50 μg/100 mL; urine 

thallium: 5000 μg/L

Numbness and weakness of the legs and hands; alopecia; fluctuating pulse and 

blood pressure; bradycardia; hypotension

Persistent ventricular 

ectopy and neurological 

dysfunction, necessitating 

placement at a nursing 

home

Roby et al. 

(1984) 

Female 61 years Unknown; serum 

thallium: 

740 μg/100 mL

Burning chest pain; paresthesia; difficulty speaking and swallowing; inability to 

walk; hypotension; acute respiratory distress syndromeb (ARDS)

Death

Roby et al. 

(1984) 

Female 80 years Unknown; serum 

thallium: 

422 μg/100 mL; urine 

thallium: 21,600 μg/L

ARDS Death

Hoffman 

(2000) 

Female Pregnant; 

ages not 

specified

150–1350 mg thallium 

(I) sulfate

Paresthesia; abdominal pain; muscle weakness; lethargy; alopecia; Mees lines

[lines of discoloration across the nails of the fingers and toes]

None specified
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6 Thallium and Compounds 

Table 2. Thallium Toxicity In Humans Following Oral Exposure 

Reference Sex Age Dose Symptomsa Final Outcome

Saha et al. 

(2004) 

Female 26 years Unknown; serum 

thallium: 

12 μg/100 mL

Headache; lethargy; abdominal pain; muscle cramps; joint pain; backache; 

numbness of fingers; alopecia; erosion of nails

Not specified

Both Sexes-Adult

Brockhaus 

et al. (1981)

Both Not 

reported

Unknown Sleep disorders; tiredness; weakness; nervousness; headache; other psychic 

alterations; neurological and muscular symptoms

Not reported

Schoer 

(1984); 

Gosselin et 

al. (1984) 

Both Adult 10–15 mg/kg thallium None specified Death (average lethal dose)

Rusyniak et 

al. (2002) 

Both Various Unknown; various 

levels were detected in 

urine

Myalgia; arthralgia; paresthesia; dysesthesia; joint stiffness; insomnia; alopecia; 

abdominal pain

Recovery in seven adults; 

five had ongoing 

psychiatric problems

Tsai et al. 

(2006) 

Both 48-year 

old 

female; 

52-year 

old male

1.5–2.4 g Confusion; disorientation; hallucination; anxiety; depression; memory 

impairment; peripheral neuropathy; erythematous skin rashes; diarrhea; 

tachycardia; alopecia

Impairment of memory and 

verbal fluency remained at 

six months; 

neuropsychological 

impairment persisted at 

nine months

Lu et al. 

(2007); Kuo 

et al. (2005) 

Both 48 and 52 

years

1.5 and 2.3 g/person 

(estimated); serum 

thallium: 

950−2056 μg/L; Urine 

thallium: 

11,325−14,520 μg/L

Nausea, vomiting; general aching muscle pain; numbness of tongue and mouth 

within a few hours; severe paresthesia and dysesthesia in hands and feet (one day 

post exposure); erythematous rash; diarrhea; urine retention; hyporeflexia; 

muscle weakness; hypoesthesia; acneiform eruptions; alopecia (1–3 weeks); 

Mees lines (2–3 months). 

Skin biopsy: parakeratosis; dilated hair follicles filled with keratin and necrotic 

sebaceous materials; mild epidermal atrophy; vacuolar degeneration of the basal 

layer.

Cutaneous nerve biopsy: axonal degeneration; loss of epidermal nerves 

indicating involvement of the small sensory nerves (2 months).

At 1-year follow-up, 

persistent paresthesia, 

dysesthesia, and 

impairment of small 

sensory nerve fibers in skin
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7 Thallium and Compounds 

Table 2. Thallium Toxicity In Humans Following Oral Exposure 

Reference Sex Age Dose Symptomsa Final Outcome

Children

Reed et al. 

(1963) 

Both 1–11 

years

Unknown Alopecia; lethargy; ataxia; abdominal pain; vomiting; abnormal reflexes; 

neuropathy; muscle weakness; coma; convulsion

Neurological abnormalities; 

retardation; psychosis; 

death

Feldman 

and 

Levisohn 

(1993)

Male 10 years Unknown; serum 

thallium: 296 μg/L; 

urine thallium: 

322 μg/24 hours

Alopecia; leg paresthesia; abdominal pain; seizures Recovery

Hoffman 

(2000) 

Both TransplacentalUnknown Premature birth; low birth weight; alopecia None specified

Ammendola 

et al. (2007) 

Male 16 years 1.3 g thallium sulfate; 

urine thallium: 

3400 μg/L

Acute stage: gastrointestinal disturbances; alopecia; clinical and 

electrodiagnostic signs of severe polyneuropathy

3 years postpoisoning: 

neurological symptoms 

making progress; 

electrophysiological signs 

of peripheral neuropathy 

mainly confined to lower 

limbs. 6 years 

postpoisoning: persistent 

weakness and sensory 

disturbances of distal lower 

extremities; neurological 

and electrodiagnostic 

abnormalities affecting 

mainly the feet.

a

ALT = alanine aminotransferase; AST = aspartate aminotransferase

b

ARDS = acute respiratory distress syndrome
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8 Thallium and Compounds 

Table 3. Thallium Toxicity in Animals Following Oral Exposurea

Reference Species Age Sex Route Dose and Duration NOAEL LOAEL Effect

Acute studies 

Leloux et al. 

(1987)

Rat 

3/sex 

Adult Both Oral (gavage) 20 mg/kg thallium (I) 

nitrate; single dose 

NIb 15 mg/kg Tl Difficulty breathing; rough coat; increased 

absolute kidney, adrenal weights; death 

Leloux et al. 

(1987) 

Rat 

10/sex/ 

group 

Adult Both Oral (gavage) 0, 1 mg/kg thallium (I) 

nitrate; once daily for 

4 days 

NI 0.77 mg/kg Tl Alopecia; diarrhea; increased absolute 

kidney, eye weights; death 

Mourelle et 

al. (1988) 

Rat 

10/group 

NSc Male Oral (gavage) 0, 10 mg/kg thallium 

(I) sulfate; single dose. 

Sacrificed at 24 hours 

to 2 days after dosing 

NI 8.1 mg/kg Tl Liver changes: increased triglycerides and 

lipid peroxidation; decreased glutathione 

and glycogen; increased alkaline 

phosphatase in serum and liver cell 

membranes 

Subchronic studies 

Downs et al. 

(1960) 

Rat/ 

5/sex/ 

group 

NS Both Oral (feed) 0, 5, 15, or 50 ppm 

thallium (I) acetate 

(corresponding to 0, 

0.4, 1.2, or 

3.9 mg/kg-day Tl);

15 weeks 

0 or 30 ppm 

(corresponding to 0 or 

2.4 mg/kg-day Tl); 

9 weeks 

0.4 mg/kg-day 

Tl* 

1.2 mg/kg-day Tl* Alopecia; increased kidney weight; 

mortality in treated and control groups. 

*The NOAEL and LOAEL are for alopecia. 

Because of reported mortality in the control 

and treated groups, a study NOAEL and 

LOAEL cannot be reliably determined. 

Downs et al. 

(1960) 

Rat 

5/sex/ 

group 

Weanling Both Oral (feed) 0, 20, 35, 50, 100, and 

500 ppm thallium (III) 

oxide (corresponding 

to 0, 1.8, 3.1, 4.5, 9.0, 

and 44.8 mg/kg-day 

Tl); 15 weeks 

NI 1.8 mg/kg-day Tl 

(20 ppm) 

Reduced body weight; alopecia; increased 

mortality; increased absolute and relative 

kidney weights 

El-Garawany 

et al. (1990)

Rat 

n = 10 

NS Male Orald 0.8 mg/kg thallium (I) 

sulfate; 90 days 

NI 0.65 mg/kg-day Tl Increased blood urea; serum creatinine; 

serum bilirubin; serum ALT 

Manzo et al. 

(1983) 

Rat 

n = 80 

NS Female Oral (DWe) 10 mg/L Tl as 

thallium (I) sulfate; 

36 weeks 

NI 1.4 mg/kg-day Tl Nerve histopathology; alopecia; mortality 
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9 Thallium and Compounds 

Table 3. Thallium Toxicity in Animals Following Oral Exposurea

Reference Species Age Sex Route Dose and Duration NOAEL LOAEL Effect

MRI (1988) Rat 

20/sex/ 

group 

45 days Both Oral (gavage) 0, 0.01, 0.05, or 

0.25 mg thallium (I) 

sulfate/kg 

(corresponding to 0, 

0.008, 0.04, or 

0.20 mg/kg-day Tl); 

90 days 

NI 0.008 mg/kg-day 

Tlf

Increased incidence of alopecia and other 

observations related to coat (rough coat, 

piloerection, shedding); lacrimation, 

exophthalmos, and miosis; and various 

behavioral observations; statistically 

significant increases in AST, LDH, and 

sodium levels; decreased blood sugar levels. 

The study authors identified 0.2 mg/kg-day 

Tl as the NOAEL. 

Reproductive and developmental toxicity

Formigli et al. 

(1986); 

Gregotti et al. 

(1985) 

Rat 

10/group 

Adult Male Oral (DW) 0, 10 ppm thallium (I) 

sulfate; 30 or 60 days 

NI 0.7 mg/kg-day Tl Testicular effects: tubular epithelium 

disarrangement; cytoplasmic vacuolation; 

reduced sperm motility; distention of 

smooth endoplasmic reticulum of Sertoli 

cells; reduced β-glucuronidase activity 

Wei (1987) Mouse NS Male Oral (DW) 0, 0.001, 0.01, 0.1, 

1.0, and 10 mg/L 

thallium (I) carbonate 

(corresponding to 0, 

0.0003, 0.003, 0.03, 

0.3, and 3 mg/kg-day 

Tl); 6 months 

NI 0.0003 mg/kg-day 

Tl 

Decreased sperm motility and counts; 

increase in deformed sperm; decrease in live 

fetuses. 

Dose estimated from an assumed average 

body weight of 20 g and drinking water 

ingestion rate of 6 mL/day. 

Rossi et al. 

(1988) 

Rat Perinatal Both [Oral 

(Mother’s, 

then pup’s 

DW)]

0, 1 mg/dL of thallium 

(I) sulfate 

Day 1 of gestation to 

weaning then thru 

60 days 

NI NI Prenatal and postnatal exposure caused a 

delay in the development of the pilus 

apparatus [the formation of hair] by 50 days; 

reduction of the α- and β-adrenergic and 

muscarinic vasomotor reactivity noted.

a

U.S. EPA (2009) Table 4-5. b

NI = not identified. 

c

NS = not specified. 

d

Presumably via gavage. 

e

DW = drinking water. 

f

See discussion of the NOAEL and LOAEL determination in Section 5.1.1 of U.S. EPA (2009). 
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10 Thallium and Compounds 

HUMAN AND ANIMAL STUDIES

Refer to the IRIS Toxicological Review (U.S. EPA, 2009) for summaries of human and 

animal studies. The principal study selected for derivation of screening subchronic and chronic 

p-RfDs (Midwest Research Institute, 1988) is summarized in Appendix A. 

Carcinogenicity Studies

No studies of the carcinogenicity of thallium or thallium compounds were identified in 

the IRIS Toxicological Review (U.S. EPA, 2009). 

Inhalation Exposures 

No studies were identified in the IRIS Toxicological Review (U.S. EPA, 2009) regarding 

the effects of subchronic or chronic inhalation exposure of animals to thallium or thallium 

compounds. 

DERIVATION OF PROVISIONAL VALUES

DERIVATION OF PROVISIONAL ORAL REFERENCE DOSES

Although there are substantial data available on human exposure to thallium, the majority 

are case reports of poisonings, suicide attempts, or accidental ingestion of rodenticides. There 

are two population surveys with oral thallium exposure through contaminated homegrown foods 

(Dolgner et al., 1983; Brockhaus et al., 1981). However, these studies are limited by the lack of 

objective tests for toxicity, reliance on the incidence of symptoms obtained from questionnaires, 

and characterization of chronic thallium exposure by measuring the levels in urine and hair at a 

single point in time (U.S. EPA, 2009). In addition, three occupational exposure studies (Ludolph 

et al., 1986; Marcus, 1985; Schaller et al., 1980) provide no conclusive associations between 

thallium exposure and any specific health effects, possibly due to the small study populations 

and study design limitations. Therefore, the available human studies are not suitable for

derivation of a p-RfD. 

There are numerous animal studies on the effects of thallium; however only four 

repeat-dose oral toxicity studies with more than one dose level were identified (Midwest 

Research Institute, 1988; Wei, 1987; Zasukhina et al., 1983; Downs et al., 1960). Wei (1987), 

Zasukhina et al. (1983), and Downs et al. (1960) were not considered adequate for RfD

derivation (see U.S. EPA (2009) for details). The MRI (1988) 90-day study in rats was 

evaluated in the IRIS Toxicological Review as a candidate principal study as the most 

comprehensive of the available thallium studies. Histopathological changes in the skin (hair 

follicle atrophy in high-dose female rats with alopecia) and clinical observations, including those 

related to animal coat (rough coat, piloerection, shedding, and alopecia), eyes (including 

lacrimation, exophthalmos, and miosis), and behavior were considered as possible endpoints for 

POD derivation. 

The conclusion reached in the IRIS Toxicological Review of Thallium and Compounds 

(U.S. EPA, 2009) was that the available toxicity database for thallium contains studies that are 

generally of poor quality. The MRI (1988) study that was selected as a candidate principal study 

for RfD derivation suffers from certain critical limitations (e.g., high background incidence of 

alopecia, lack of histopathological examination of skin tissue in low- and mid-dose groups, and 
FINAL

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11 Thallium and Compounds 

inadequate examination of objective measures of neurotoxicity), and there are particular 

difficulties in the selection of appropriate endpoints. Therefore, a RfD for soluble thallium salts 

was not derived. 

However, Appendix A of this document contains Screening Values (screening subchronic 

and chronic p-RfD) that may be useful in certain instances. See the attached Appendix A.

DERIVATION OF INHALATION REFERENCE CONCENTRATIONS

As reviewed in the Toxicological Review of Thallium and Compounds (U.S. EPA, 2009) 

no subchronic or chronic p-RfC values can be derived because there are no suitable studies of 

inhalation exposures. 

CANCER WEIGHT-OF-EVIDENCE DESCRIPTOR

The Cancer WOE descriptor for thallium is provided in the Toxicological Review of 

Thallium and Compounds (U.S. EPA, 2009) as “Inadequate Information to Assess Carcinogenic 

Potential (both oral and inhalation).” 

DERIVATION OF PROVISIONAL CANCER POTENCY VALUES

The lack of data on the carcinogenicity of any thallium compound as indicated in the 

IRIS Toxicological Review (U.S. EPA, 2009) precludes the derivation of quantitative estimates 

for either oral (p-OSF) or inhalation (p-IUR) exposure. 
FINAL

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12 Thallium and Compounds 

APPENDIX A. PROVISIONAL SCREENING VALUES

For the reasons noted in the main document, it is inappropriate to derive a subchronic or 

chronic p-RfD for thallium. However, information is available which, although insufficient to 

support derivation of a provisional toxicity value, under current guidelines, may be of limited use 

to risk assessors. In such cases, the Superfund Health Risk Technical Support Center 

summarizes available information in an appendix and develops a screening value. Users of 

screening toxicity values in an appendix to a PPRTV assessment should understand that there is 

considerably more uncertainty associated with the derivation of a supplemental screening 

toxicity value than for a value presented in the body of the assessment. Questions or concerns 

about the appropriate use of screening values should be directed to the Superfund Heath Risk 

Technical Support Center. 

DERIVATION OF SCREENING PROVISIONAL ORAL REFERENCES DOSES

The 90-day study by MRI (1988) is selected as the principal study for derivation of the 

screening subchronic and chronic p-RfD. This study was summarized in the Toxicological 

Review (U.S. EPA, 2009) as follows: 

In a study performed by Midwest Research Institute (Midwest Research 

Institute, 1988) for EPA’s Office of Solid Waste, male and female SpragueDawley rats (45 days old, 20/sex/group) were administered 0 (untreated and 

vehicle controls), 0.01, 0.05, or 0.25 mg/kg-day of an aqueous solution of thallium 

(I) sulfate (approximately 0, 0.008, 0.04, or 0.20 mg/kg-day Tl) by gavage for 

90 days. The study was conducted in compliance with EPA good laboratory 

practice (GLP) mandates. The MRI (1988) study is an unpublished study; 

accordingly, an external peer review was initiated by EPA in November 2006. 

Body weight, food consumption, hematologic and clinical chemistry parameters, 

ophthalmologic examinations, gross pathological observations, and organ 

weights (liver, kidneys, brain, gonads, spleen, heart, and adrenals) were recorded 

for all animals. Neurotoxicological examinations (three times/week) were 

performed on six rats/sex/group; these examinations were apparently 

observational (further details were not provided in the study report). Tissues 

from three rats/sex/group were prepared for neuropathologic examination. 

Complete histopathologic examinations (including neuropathologic 

examinations) were conducted for the vehicle control and 0.2 mg/kg-day Tl 

groups only; for the other three groups, only the livers, lungs, kidneys and gross 

lesions were examined histopathologically. Neuropathologic examinations 

included the following: dorsal and ventral root fibers of the spinal nerves, dorsal 

root ganglia, spinal cord at C3–C6 and L1–L4, and six sections of the brain. 

There were no statistically significant differences in body weight, food 

consumption, or absolute and relative organ weights among control groups and 

groups receiving thallium (I) sulfate (Midwest Research Institute, 1988). The 

study authors concluded that the histopathologic examination did not reveal any 

treatment-related effects. 
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13 Thallium and Compounds 

Lacrimation (secretion of tears), exophthalmos (abnormal protrusion of 

the eyeball), and miosis (contraction of the pupil) were observed at higher 

incidences in the treated male and female rats compared with both untreated and 

vehicle controls (see Table B.1;Midwest Research Institute, 1988). 

Ophthalmologic examination and gross and histopathologic examination of the 

eyes, however, revealed no treatment-related abnormalities. The incidence of 

clinical observations related to the coats (including rough coat, piloerection, 

shedding, and alopecia) and behavior (including aggression, tension/agitation, 

hyperactivity, vocalization, and self-mutilation) were also elevated in male and 

female rats at the higher doses (see Table B.1; Midwest Research Institute, 1988). 

As noted above, the incidence of alopecia was increased, particularly in 

female rats (see Table B.2; Midwest Research Institute, 1988). Examination of 

individual animal clinical observation data for female rats from the MRI (1988) 

study showed that alopecia was first observed in control and treated groups 

anywhere from study day 44 to 60. Based on a statistical analysis performed by 

the U.S. EPA, the incidence of alopecia (total number of cases in each dose 

group) was statistically significantly elevated relative to controls in mid-dose 

males and mid- and high-dose females. Most instances of alopecia in females 

were attributed to barbering behavior (where fur was present but cropped short). 

Of the 12 high-dose females with alopecia, 5 instances were not totally attributed 

to barbering behavior. Histopathologic examination revealed atrophy of the hair 

follicles in two high-dose female rats. Because the skin was examined for 

histopathologic changes only in the vehicle control and high-dose groups, no 

information on dermal histopathology was available for the low- and mid-dose 

groups. The two high-dose females with atrophy of the hair follicles also had 

alopecia; whether the hair follicle atrophy and alopecia occurred at the same 

location on the rats could not be determined from the study report. The study 

authors concluded that the alopecia was attributable to the cyclic pattern of hair 

growth in rodents. Consequently, the authors did not consider these findings to 

be toxicologically significant. 

Subtle but statistically significant changes were observed in several blood 

chemistry parameters that the investigators considered probably treatment 

related (Midwest Research Institute, 1988). Specifically, dose-related increases 

in AST, lactate dehydrogenase (LDH), and sodium levels and decreases in blood 

sugar levels were detected in male and female rats after 30 and 90 days of 

exposure. Reported values for the selected blood chemistry parameters are 

summarized in Table B.3. Other changes in blood chemistry parameters were 

less consistent across species, dose groups, and exposure durations. 

At 90 days, the differences in AST, LDH, sodium, and blood sugar levels 

in dosed male and female rats were no greater than +31, +38, +4, and -21%, 

respectively, of the vehicle control group values (Midwest Research Institute, 

1988). The investigators observed that the increases in AST and LDH levels 

could indicate a possible effect of treatment on cardiac function, that increases in 

LDH coupled with subtle changes in electrolytes could indicate an effect on renal 

function, and that, in rare instances, a decrease in blood sugar coupled with an 

increase in sodium occurs as a defense mechanism for maintaining cellular 
FINAL

9-19-2012 

14 Thallium and Compounds 

integrity. The investigators concluded that none of the changes observed in the 

blood chemistries of male or female rats during the study were of sufficient 

magnitude to significantly affect the health status of the animals. Further, 

histopathologic evaluation did not confirm any cellular damage suggested by the 

clinical chemistry findings. 

The authors concluded that the minor dose-related changes in this study did not affect the 

health status of the treated animals and therefore were not toxicologically significant and 

identified the highest dose, 0.25 mg/kg-day thallium (I) sulfate (0.20 mg/kg-day Tl [2 moles of 

soluble thallium (I) in one mole of the soluble thallium salt, Tl2SO4]), as a no-observed-effect 

level (NOEL). However, after review, EPA (2009) came to different conclusions as indicated 

below: 

Several candidates for critical effects were considered, but ultimately EPA (2009) 

considered that only two endpoints were appropriate for RfD development: (1) hair follicle 

atrophy in female rats that also had alopecia and (2) clinical observations; those related to animal 

coat (rough coat, piloerection, shedding, and alopecia), eyes (including lacrimation, 

exophthalmos, and miosis) and behavior. Endpoint (2) was not selected as the critical effect in 

this PPRTV because there is a high background occurrence of alopecia in control animals and 

the potential for misclassification. As a result, there is some uncertainty about the incidence of 

treatment-related alopecia in the treated animals. In addition, the underlying basis for other

clinical observations is unknown. Endpoint (1) was selected as the critical effect because 

atrophy of hair follicles is consistent with the atrophic changes observed in the cases of human 

thallium poisoning (e.g., follicular plugging of the skin including alopecia) and may be the best 

indicator for human response to thallium exposure. For this PPRTV, hair follicle atrophy is 

selected as the critical effect because it may serve as a better indicator of alopecia resulting from 

thallium exposure. 

The high dose (0.25 mg/kg-day thallium [I] sulfate or 0.2 mg/kg-day soluble Tl) was 

characterized as a LOAEL. Because skin tissue from rats in the low- and mid-dose groups was 

not examined for histopathologic changes, the NOAEL for this endpoint cannot be determined 

with certainty. Given the low incidence of hair follicle atrophy in females in the high dose group 

and absence of cases of hair follicle atrophy in male rats, the mid-dose can reasonably be 

assumed to approximate a NOAEL for skin histopathology. Thus, an estimated NOAEL of 

0.05 mg/kg-day thallium (I) sulfate (Tl2SO4) or 0.04 mg/kg-day Tl (soluble form) was used as 

the POD for hair follicle atrophy from the MRI (1988) study. 

The screening subchronic p-RfD was derived using a composite UF of 1000 as follows: 

Screening Subchronic p-RfD = NOAEL ÷ UFC

(Thallium [I] Sulfate) = 0.05 mg/kg-day Tl2SO4 ÷ 1000 

= 5 × 10-5 mg/kg-day Thallium (I) Sulfate

Screening Subchronic p-RfD = NOAEL ÷ UFC

(Soluble Thallium; 2 moles) = 0.04 mg/kg-day Tl ÷ 1000 

= 4 × 10-5 mg/kg-day Tl
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15 Thallium and Compounds 

An interspecies UFA of 10 is applied for extrapolation from laboratory animals to humans 

since no information is available to characterize the toxicokinetic or toxicodynamic differences 

between experimental animals and humans.

An intraspecies UF H of 10 is applied to account for variation in human susceptibility in 

the absence of information on the variability of response to thallium in the human population. 

A database UFD of 10 is applied to account for a lack of adequate developmental toxicity 

studies and a two-generation reproductive study, and additional uncertainty associated with the 

limited data available on neurotoxicity.

An UFS of 1 applied for extrapolation from subchronic studies since the principal study is 

considered a subchronic study. 

An UFL of 1 is applied to account for extrapolation from LOAEL to NOAEL, because a 

NOAEL was utilized.

The screening chronic RfD was derived using a composite UF of 3000 as follows: 

Screening Chronic p-RfD = NOAEL ÷ UFC

(Thallium [I] Sulfate) = 0.05 mg/kg-day Tl2SO4 ÷ 3000 

= 2 × 10-5 mg/kg-day Thallium (I) Sulfate

Screening Chronic p-RfD = NOAEL ÷ UFC

(Soluble Thallium; 2 moles) = 0.04 mg/kg-day Tl ÷ 3000 

= 1 × 10-5 mg/kg-day Tl 

An interspecies UFA of 10 is applied for extrapolation from laboratory animals to humans 

since no information is available to characterize the toxicokinetic or toxicodynamic differences 

between experimental animals and humans.

An intraspecies UFH of 10 is applied to account for variation in human susceptibility in 

the absence of information on the variability of response to thallium in the human population. 

A database UFD of 10 is applied to account for a lack of adequate developmental toxicity 

studies and a two-generation reproductive study, and additional uncertainty associated with the 

limited data available on neurotoxicity.

An UFS of 3 is applied to account for extrapolation from subchronic to chronic exposure 

duration. As explained in the IRIS Toxicological Review, “Oral toxicity data for thallium 

suggest that an UF of 10 would overestimate the difference in response following subchronic and 

chronic oral exposures. Effects on the coat/skin as well as other clinical observations occur 

within weeks of exposure to thallium (i.e., these sensitive effects do not require chronic exposure 

in order to manifest).” 

An UFL of 1 is applied to account for extrapolation from LOAEL to NOAEL, because a 

NOAEL was utilized. 
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16 Thallium and Compounds 

Based on molecular weight (MW) adjustments and stoichiometric calculations, a 

summary of screening subchronic and chronic p-RfDs for other soluble thallium salts is 

presented in Table A.1. 

Table A.1. Screening Subchronic and Chronic p-RfDs for Other Thallium Salts

Thallium Salt (Formula; 

MW)

Screening Subchronic p-RfD

(mg/kg-day)

Screening Chronic p-RfD

(mg/kg-day)

Thallium (I) acetatea

(TlC2H3O2; 263.43)

3 × 10-5 6 × 10-6

Thallium (I) carbonateb 

(Tl2CO3; 468.78)

5 × 10-5 2 × 10-5

Thallium (I) chloridea 

(TlCl; 239.84)

2 × 10-5 6 × 10-6

Thallium (I) nitratea 

(TlNO3; 266.39)

3 × 10-5 7 × 10-6

a

Based on the screening p-RfD for soluble thallium and the molecular weight conversion as follows: screening pRfD of (1:1) thallium salt = screening p-RfD of soluble thallium (2 moles) ÷ 2 × (Molecular weight of (1:1) 

thallium salt ÷ Molecular weight of one mole of thallium in the salt), rounded to one significant figure. For 

example, for the screening chronic p-RfD of thallium (I) acetate, 1 × 10-5 mg/kg-day Tl ÷ 2 × 

MW(TlC2H3O2)/MW(Tl) = 1 × 10-5 mg/kg-day ÷ 2 × (263.43/204.38) = 6 × 10-6 mg/kg-day. b

Based on the screening p-RfD for thallium (I) sulfate and the molecular weight conversion as follows: 

screening p-RfD of (2:1) thallium salt = screening p-RfD of thallium (I) sulfate × (Molecular weight of (2:1) 

thallium salt ÷ Molecular weight of thallium [I] sulfate), rounded to one significant figure. For example, for the 

screening chronic p-RfD of thallium (I) carbonate, 2 × 10-5 mg/kg-day Tl2SO4 × MW(Tl2CO3)/MW(Tl2SO4) = 2 × 

10-5 mg/kg-day × (468.78/504.82) = 2 × 10-5 mg/kg-day.
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17 Thallium and Compounds 

APPENDIX B. DATA TABLES

Table B.1. Selected Clinical Observations in Sprague-Dawley Rats Treated 

with Thallium Sulfate for 90 Daysa

Observationb Untreated Control Vehicle Control 0.008 mg/kg-day 0.04 mg/kg-day 0.2 mg/kg-day

Male

Coat/skin 

Rough coat 1/20 3/20 11/20 16/20 19/20 

Piloerection 0/20 0/20 1/20 4/20 13/20 

Shedding 0/20 0/20 4/20 10/20 8/20 

Alopecia 2/20 1/20 4/20 9/20 4/20 

Eyes 

Lacrimation 1/20 6/20 19/20 20/20 20/20 

Exophthalmos 1/20 5/20 12/20 20/20 20/20 

Miosis 0/20 1/20 5/20 7/20 15/20 

Behaviorc 3/20 0/20 7/20 6/20 7/20 

Female

Coat/skin 

Rough coat 1/20 0/20 1/20 5/20 11/20 

Piloerection 0/20 0/20 0/20 3/20 8/20 

Shedding 0/20 0/20 2/20 3/20 13/20 

Alopecia 4/20 1/20 4/20 9/20 12/20 

Eyes 

Lacrimation 7/20 6/20 20/20 20/20 20/20 

Exophthalmos 5/20 6/20 19/20 20/20 20/20 

Miosis 2/20 3/20 1/20 11/20 8/20 

Behaviorc 2/20 2/20 0/20 1/20 7/20 

a

MRI (1988). Table was obtained directly from Table 4-2 in U.S. EPA (2009). b

Listed as number of animals with the sign observed at least once during the 90-day study. c

Animals exhibiting one or more behavioral observations at least once during the 90-day study, including the 

following: aggression, tension/agitation, hyperactivity, vocalization, self-mutilation. 
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18 Thallium and Compounds 

Table B.2. Incidence of Alopecia in Ratsa

Dose

(mg/kg-day Tl)

Males Females

Alopeciab,c Hair follicle atrophyc Alopeciab,c Hair follicle atrophyd

0 (untreated control) 2/20 --e 4/20 --e

0 (vehicle control) 1/20 0/20 1/20 0/20

0.008 4/20 --e 4/20 --e

0.04 9/20f --e 9/20g --e

0.2 4/20 0/20 12/20f 2/20

a

MRI (1988). Table was obtained directly from Table 4-3 in U.S. EPA (2009). b

Number of animals with alopecia at least once during the 90-day study based on clinical observations. c

Of the animals with alopecia, the following are the numbers of cases in each dose group that the study authors stated 

are not totally attributed to “barbering behavior”: 

Males: untreated control, 1; vehicle control, 0; 0.008 mg/kg-day, 2; 0.04 mg/kg-day, 4; 0.2 mg/kg-day, 1. 

Females: untreated control, 0; vehicle control, 0; 0.008 mg/kg-day, 1; 0.04 mg/kg-day, 3; 0.2 mg/kg-day, 5. d

Based on histopathologic observation. 

e

Skin was not examined for histopathologic lesions. 

f

Incidence of alopecia (total number of cases) was statistically significantly elevated (p < 0.05) relative to incidence in 

vehicle control, incidence in untreated control, and pooled incidence of vehicle and untreated control, based on 

Fisher’s exact test performed by EPA. 

g

Incidence of alopecia (total number of cases) was statistically significantly elevated (p < 0.05) relative to incidence in 

vehicle control and pooled incidence of vehicle and untreated control, based on Fisher’s exact test performed by 

EPA. 
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19 Thallium and Compounds 

Table B.3. Selected Blood Chemistry Valuesa

Endpoint

Study 

Day

Untreated 

Control

Vehicle 

Control

0.008 

mg/kg-day

0.04 

mg/kg-day

0.2 

mg/kg-day

Malesb

AST (I.U.) 30 

90 

91 ± 26.5 

77 ± 19.7 

108 ± 18.6 

87 ± 17.8 

128 ± 24.5c

99 ± 20.4 

134 ± 29.0c,d

113 ± 27.0c,d

152 ± 20.1c,d

114 ± 31.1c,d

LDH (I.U.) 30 

90 

795 ± 322 

587 ± 305 

1206 ± 424c

856 ± 385 

1333 ± 340c 

1003 ± 363c 

1396 ± 407c

1071 ± 507c

1802 ± 341c,d

1119 ± 477c 

Na (meq/L) 30 

90 

148 ± 1.3 

144 ± 1.6 

149 ± 2.4 

147 ± 2.0c

152 ± 4.0c

147 ± 1.9c

154 ± 2.5c,d

149 ± 2.0c,d

153 ± 2.1c,d 

151 ± 2.2c,d

Blood sugar 

(mg/l00 mL) 

30 

90 

100 ± 22.1 

158 ± 15.6 

97 ± 18.1 

138 ± 16.8c

93 ± 10.0 

131 ± 17.6c

90 ± 18.3 

121 ± 15.7c

62 ± 14.8c,d

113 ± 22.4c,d

Femalesb

AST (I.U.) 30 

90 

95 ± 22.8 

77 ± 19.2 

115 ± 30.3 

90 ± 19.1 

127 ± 27.8c

93 ± 33.1 

149 ± 26.8c,d

111 ± 30.7c 

154 ± 18.2c,d

112 ± 31.0c 

LDH (I.U.) 30 

90 

1047 ± 335 

745 ± 320 

1277 ± 495 

881 ± 273 

1402 ± 501 

823 ± 354 

1763 ± 370c,d

1044 ± 436 

1764 ± 361c,d

1219 ± 338b 

Na (meq/L) 30 

90 

148 ± 1.7 

146 ± 1.8 

150 ± 1.9 

146 ± 1.0 

153 ± 4.1c,d

148 ± 1.8c,d 154 ± 2.8c,d 

150 ± 2.0c,d 

155 ± 2.5c,d

152 ± 1.0c,d

Blood sugar 

(mg/l00mL) 

30 

90 

103 ± 23.9 

110 ± 28.7 

80 ± 13.3c

89 ± 15.9 

80 ± 9.0c

103 ± 19.9 

67 ± 20.0c

88 ± 20.4 

50 ± 11.8c,d

70 ± 18.0c

a

MRI (1988). Table was obtained directly from Table 4-4 in U.S. EPA (2009). b

Mean ± standard deviation of 7–10 rats. c

Significantly different (p <0.05) from the untreated control group. d

Significantly different (p < 0.05) from the vehicle control group. 
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20 Thallium and Compounds 

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Brockhaus, A; Dolgner, R; Ewers, U; Krämer, U; Soddemann, H; Wiegand, H. (1981). Intake 

and health effects of thallium among a population living in the vicinity of a cement plant 

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Cavanagh, JB; Fuller, NH; Johnson, HR; Rudge, P. (1974). The effects of thallium salts, with 

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Downs, AJ. (1993). Chemistry of aluminum, gallium, indium, and thallium. London, UK: 

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21 Thallium and Compounds 

Gefel, A; Liron, M; Hirsch, W. (1970). Chronic thallium poisoning. Isr J Med Sci 6: 380-382. 

Gosselin, RE; Smith, RP; Hodge, HC; Braddock, JE. (1984). Clinical toxicology of commercial 

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Gregotti, C; Di Nucci, A; Formigli, L; Sabbioni, E; Manzo, L. (1985). Altered testicular enzyme 

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chronic occupational thallium poisoning in a glass factory. Ind Health 36: 300-303. 

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