UKPID MONOGRAPH
TELLURIUM HEXAFLUORIDE
WN Harrison PhD CChem MRSC
SM Bradberry BSc MB MRCP
S Meacham BSc
JA Vale MD FRCP FRCPE FRCPG FFOM
National Poisons Information Service
(Birmingham Centre),
West Midlands Poisons Unit,
City Hospital NHS Trust,
Dudley Road,
Birmingham
B18 7QH
This monograph has been produced by staff of a National Poisons
Information Service Centre in the United Kingdom. The work was
commissioned and funded by the UK Departments of Health, and was
designed as a source of detailed information for use by poisons
information centres.
Peer review group: Directors of the UK National Poisons Information
Service.
TELLURIUM HEXAFLUORIDE
Toxbase summary
Type of product
Tellurium hexafluoride is a gas at room temperature and is used as a
chemical reagent.
Toxicity
Acute poisoning is rare. Due to its gaseous nature, inhalation and
topical exposure are most likely. Ingestion has not been reported.
Features
Topical
- Irritant to skin and eyes.
- May cause dermal discolouration.
Inhalation
- A garlic odour to the breath, sweat and urine is
characteristic of tellurium exposure.
- A metallic taste, nausea, loss of appetite, tiredness,
reduced sweating and unspecified ECG changes have been
reported.
- May cause respiratory tract irritation, although reports of
significant pulmonary toxicity are rare.
Management
Dermal
1. If possible the patient should remove soiled clothing and wash
him/herself.
2. Wash contaminated hair and skin with soap and copious amounts of
water.
3. Pay special attention to skin folds, fingernails and ears.
Ocular
1. Immediately irrigate the affected eye thoroughly with tepid water
or 0.9 per cent saline for at least 10-15 minutes.
2. Any particles lodged in the conjunctival recesses should be
removed.
3. Continue irrigation with saline infusion using drip tubing.
4. Repeated instillation of local anaesthetic may reduce discomfort
and help more thorough decontamination.
5. Corneal damage may be detected by instillation of fluorescein.
6. Patients with corneal damage and those whose symptoms do not
resolve rapidly should be referred for ophthalmological
assessment.
Inhalation
1. Remove from exposure
2. Treat symptomatically and supportively.
3. If symptoms occur perform a chest X-ray, ECG, biochemical and
haematological profiles.
4. Collect urine and blood for tellurium concentration measurements
to confirm diagnosis although these assays are not widely
available. Check with NPIS.
5. It has been suggested that ascorbic acid may reduce the garlic
odour from tellurium intoxication (De Meio, 1947) but this has
not been confirmed.
6. Dimercaprol increases tellurium toxicity and should not be used.
References
Blackadder ES, Manderson WG.
Occupational absorption of tellurium: a report of two cases.
Br J Ind Med 1975; 32: 59-61.
De Meio RH.
Tellurium. II. Effect of ascorbic acid on the tellurium breath.
J Ind Hyg Toxicol 1947; 29: 393-5.
Kron T, Hansen C, Werner E.
Renal excretion of tellurium after peroral administration of tellurium
in different forms to healthy human volunteers.
J Trace Elem Electrolytes Health Dis 1991; 5: 239-44.
Müller R, Zschiesche W, Steffen HM, Schaller KH.
Tellurium-intoxication.
Klin Wochenschr 1989; 67: 1152-5.
Substance name
Tellurium hexafluoride
Origin of substance
Prepared by direct fluorination of tellurium metal.
(MERCK, 1996)
Synonyms
Tellurium fluoride (NIOSH, 1997)
Chemical group
A compound of tellurium, a group VI A element.
Reference numbers
CAS 7783-80-4 (DOSE, 1994)
RTECS WY2800000 (RTECS, 1997)
UN 2195 (DOSE, 1994)
HAZCHEM CODE NIF
Physicochemical properties
Chemical structure
TeF6 (DOSE, 1994)
Molecular weight
241.59 (DOSE, 1994)
Physical state at room temperature
Gas (SAX'S, 1996)
Colour
Colourless (SAX'S, 1996)
Odour
Repulsive (SAX'S, 1996)
Viscosity
NIF
pH
NIF
Solubility
Slowly absorbed by water. (MERCK, 1996)
Autoignition temperature
NIF
Chemical interactions
Corrodes mercury.
Hydrolyzed by aqueous potassium hydroxide.
(MERCK, 1996)
Major products of combustion
Fumes of fluoride and tellurium. (SAX'S, 1996)
Explosive limits
NA
Flammability
Nonflammable gas (NIOSH, 1997)
Boiling point
Sublimes at -38.9°C (SAX'S, 1996)
Density
4.006 at -191°C (solid); 2.499 at -10°C (liquid)
(SAX'S, 1996)
Vapour pressure
NIF
Relative vapour density
8.3 (Air = 1 at boiling point of tellurium hexafluoride)
(HSDB, 1997)
Flash point
NA
Reactivity
Hydrolyzed by water to telluric acid, H6TeO6.
(MERCK, 1996)
Uses
A chemical reagent.
Hazard/risk classification
NIF
INTRODUCTION
Tellurium hexafluoride is a hexavalent compound of tellurium. It is a
gas at room temperature and so exposure is mainly dermal, ocular and
via inhalation.
Tellurium exposure is characterized by a distinctive garlic odour
which is due to formation of the hepatic metabolite dimethyl
telluride.
EPIDEMIOLOGY
Tellurium hexafluoride poisoning is rare. Only occupational exposure
has been reported (Blackadder and Manderson, 1975).
MECHANISMS OF TOXICITY
There are few data on the mechanism of toxicity of tellurium or its
compounds. Animal studies suggest tellurium may affect the conversion
of squalene to cholesterol so interfering with neurotransmission via
demyelination (Gerhardsson et al, 1986).
Impaired secretory nerve neurotransmission is the proposed mechanism
of impaired saliva and sweat secretion in humans and of reduced
gastric acid secretion in animals poisoned with tellurium (Shie and
Deeds, 1920).
There is some evidence that the aroma of fresh garlic is caused by a
high tellurium content. This may contribute to garlic's
cholesterol-lowering properties (Larner, 1995).
In vitro studies demonstrate that tellurite (Te4+) ions can
penetrate the erythrocyte membrane and, in the presence of reduced
glutathione, form telluride (Te2+) which causes irreversible membrane
damage and hence haemolysis (De Meio and O'Leary, 1975; Kurantsin-
Mills et al, 1988). Tellurate (Te6+) ions do not penetrate the
erythrocyte membrane. Haemolysis has been observed in animals poisoned
with tellurium (Shie and Deeds, 1920) but not as a feature of
tellurium intoxication in man.
TOXICOKINETICS
Absorption
Two male research chemists developed characteristic features of
systemic tellurium intoxication from inhalation of tellurium
hexafluoride gas (Blackadder and Manderson, 1975).
Tellurium dusts and fumes can be absorbed via the lung. Workers
exposed to tellurium concentrations up to 0.1 mg/m3 had urine
tellurium concentrations up to 0.06 mg/L (Steinberg et al, 1942).
The mean (± SD) gastrointestinal absorption in healthy volunteers
ingesting between 15 and 57 µg has been estimated as ten per cent (± 4
per cent) for elemental tellurium, 23 per cent (± 9 per cent) for
tellurate and 21.5 per cent (no SD given) for tellurite (Kron et al,
1991).
Ingestion of 0.5 µg tellurium oxide produced a garlic breath odour
within 75 minutes which lasted for 30 hours (Reisert, 1884).
Organometallic complexes of tellurium and soluble tellurium salts can
be absorbed through the skin (Blackadder and Manderson, 1975).
Distribution
Tellurium is distributed widely with high concentrations particularly
in kidneys, liver, bone, brain and testes (Meditext, 1997).
Excretion
Excretion is mainly renal although small amounts of tellurium are
exhaled as dimethyl telluride which has a distinctive garlic odour
which may persist for many days; Reisert (1884) reported garlic breath
odour for 237 days following ingestion of 15 mg tellurium oxide. The
susceptibility to this effect varies considerably between individuals
and is exacerbated by alcohol consumption (Cerwenka and Cooper, 1961).
CLINICAL FEATURES: ACUTE EXPOSURE
Dermal exposure
Blue-black patches in the webs of the fingers and streaks on the neck
were observed in two postgraduate chemists who handled volatile
tellurium esters. The discolouration was believed to be due to
deposition of elemental tellurium in the dermis and subcutaneous
tissue (Blackadder and Manderson, 1975).
Ocular exposure
Some tellurium compounds are irritant although there are no reports of
ocular exposure to tellurium or its compounds producing adverse
effects.
Exposure to either hydrogen telluride or to shampoo containing
tellurium oxide has not caused eye problems (Grant and Schuman, 1993).
Inhalation
No pulmonary features were reported when two postgraduate chemists
were exposed to some 50 g tellurium hexafluoride gas which leaked from
a cylinder into a small laboratory. The first individual developed a
metallic taste, anorexia and tiredness and, after two days, an
erythematous papular vesicular rash on the hands, arms and neck. This
was diagnosed as contact dermatitis, possibly from wearing rubber
gloves, although the ability of tellurium to inhibit sweating may have
contributed. The second person affected experienced only a metallic
taste and somnolence. Both patients developed a garlic odour to the
breath, sweat and urine which persisted for several weeks (Blackadder
and Manderson, 1975). Haematological and biochemical profiles and
chest X-ray were normal.
CLINICAL FEATURES: CHRONIC EXPOSURE
There are no reports regarding chronic exposure to tellurium
hexafluoride though features similar to those observed for other
tellurium compounds may be expected.
Inhalation
Thirteen individuals working near the blast furnaces in a lead
refinery were examined for signs of tellurium exposure (Shie and
Deeds, 1920). The workers were believed to have been exposed to
hydrogen telluride though no exposure data were given. Seven had a
garlic odour to the breath, sweat and urine, and dryness and a
metallic taste in the mouth. Five had "considerable inhibition of the
sweat function" and three developed dry and itchy skin, anorexia,
nausea, vomiting, depression and somnolence.
A survey of ninety-eight workers exposed to 0.01-0.1 mg/m3 tellurium
for 22 months revealed similar effects. The most common findings were
a garlic odour of the breath (84 individuals), dryness of the mouth
(32), a metallic taste (27) and garlic odour of the sweat (20). Other
symptoms included somnolence (16), loss of appetite (9) and nausea
(3). No evidence of sweat suppression was found. Urinalysis revealed
increased tellurium concentrations (0.01 to greater than 0.06 mg/L) in
the exposed group compared to controls. Symptoms occurred even in
those with urine tellurium concentrations less than 0.01 mg/L, though
the frequency increased at higher tellurium concentrations with
somnolence and a garlic sweat odour occurring only in workers with a
urine tellurium concentration greater than 0.01 mg/L (Steinberg et al,
1942).
MANAGEMENT
Dermal exposure
If possible the patient should remove any contaminated clothing
him/herself. Affected areas of skin should be washed with copious
quantities of water.
Ocular exposure
Irrigate immediately with lukewarm water or preferably saline for at
least 10-15 minutes. Specialist ophthalmological advice should be
sought if any abnormality is detected or suspected on examination and
in those whose symptoms do not resolve rapidly.
Inhalation
Immediate management involves removal from exposure, establishment of
a clear airway and administration of supplemental oxygen if necessary.
Other symptomatic and supportive measures should be dictated by the
patients condition.
Antidotes
Animal studies
Four guinea pigs were administered 5 mg intramuscular dimercaprol
eight hours prior to the intramuscular injection of 75 mg tellurium
oxide. A second group of four similarly poisoned guinea pigs received
dimercaprol eight hours after tellurium oxide injection. Both groups
then received dimercaprol 5 mg tds for 24 hours and 5 mg bd for a
further 24 hours. There was 100 per cent mortality in the two
dimercaprol administered groups (n=8) within 48 hours (and all animals
showed pronounced haematuria) whereas the 48 hour survival rate in
control animals (n=4) administered tellurium oxide alone was 75 per
cent. A single guinea pig administered only intramuscular dimercaprol
5 mg every eight hours for 24 hours remained healthy. The weights of
the animals were not stated (Armdur, 1958).
Clinical studies
Three men exposed to tellurium fumes developed a strong garlic breath
odour and were treated with 2.5 mg/kg dimercaprol intramuscularly
every four hours for 24 hours, every six hours for a further 24 hours
and then daily for six days. Each patient reported accentuation of the
garlic odour following the injection and the odour disappeared one to
four days after the cessation of treatment. There was no evidence of
enhanced tellurium elimination with therapy (Amdur, 1947).
Ascorbic acid
Animal studies
The reduction in garlic odour from rabbits and guinea pigs intoxicated
with tellurium following administration of ascorbic acid (route not
described) has been reported. The proposed mechanism is reduction of
ionized to elemental tellurium with decreased dimethyl telluride
formation (De Meio, 1947).
Intramuscular ascorbic acid 25 mg tds for 24 hours then 25 mg bd for a
further 24 hours did not increase the one week survival of guinea pigs
injected intramuscularly with 75 mg tellurium oxide compared to
controls (Amdur, 1958).
Clinical studies
Workers exposed to tellurium dust were treated with 8-10 mg/kg
ascorbic acid (route not stated) one to three times daily. A reduction
in garlic breath odour was noted which recurred on cessation of
treatment (De Meio, 1947).
A 37 year old woman who ingested an unknown amount of tellurium was
treated with ascorbic acid 200 mg daily (route not stated). She
recovered fully though a garlic odour of the breath persisted from
some ten months (Müller et al, 1989).
Antidotes: Conclusions and recommendations
1. Animal studies suggest dimercaprol increases tellurium toxicity
and, as there is no evidence that it enhances tellurium
elimination, it should not be employed.
2. Ascorbic acid may decrease the extent of garlic odour in persons
with tellurium intoxication although this has not been confirmed
in controlled studies.
MEDICAL SURVEILLANCE
The most obvious indication of tellurium exposure is a garlic odour to
the breath, which occurs in association with urine tellurium
concentrations greater than 1 µg/L (Gerhardsson et al, 1986). This
clinical indication of tellurium exposure may be masked in those with
badly smelling breath (i.e. bronchiectasis, grossly carious teeth,
severe gingivitis) (Gerhardsson et al, 1986).
Normal concentrations in biological fluids
The "upper normal limits" for tellurium in non-occupationally exposed
individuals have been reported as 1.0 µg/L in serum and 1.0 µg/L in
urine (Müller et al, 1989).
OCCUPATIONAL DATA
Occupational exposure standard
Tellurium and compounds, except hydrogen telluride. Long-term exposure
limit 0.1 µg/m3 (as Te) (Health and Safety Executive, 1997).
OTHER TOXICOLOGICAL DATA
Carcinogenicity
There are no data on the possible carcinogenic effects of tellurium
hexafluoride in humans.
Reprotoxicity
Pregnant rats fed diets containing 500 to 3500 ppm tellurium gave
birth to hydrocephalic (non-obstructive) offspring, the incidence of
hydrocephalus being proportional to the tellurium dose (Duckett,
1970). The mechanism of this effect is not known.
There are no data on the possible reproductive effects of tellurium
hexafluoride in humans.
Genotoxicity
An increase in the incidence of chromosome breakage was found when
in vitro human leukocytes were treated for 48 hours with 1.2 x 10-8
mol/L sodium tellurite and 2.4 x 10-7 mol/L ammonium tellurite (Paton
and Allison, 1972).
Fish Toxicity
NIF
EC Directive on Drinking Water Quality 80/778/EEC
NIF
WHO Guidelines for Drinking Water Quality
NIF
AUTHORS
WN Harrison PhD CChem MRSC
SM Bradberry BSc MB MRCP
S Meacham BSc
JA Vale MD FRCP FRCPE FRCPG FFOM
National Poisons Information Service (Birmingham Centre),
West Midlands Poisons Unit,
City Hospital NHS Trust,
Dudley Road,
Birmingham
B18 7QH
UK
This monograph was produced by the staff of the Birmingham Centre of
the National Poisons Information Service in the United Kingdom. The
work was commissioned and funded by the UK Departments of Health, and
was designed as a source of detailed information for use by poisons
information centres.
Date of last revision
28/1/98
REFERENCES
Amdur ML.
Tellurium. Accidental exposure and treatment with BAL in oil.
Occup Med 1947; 3: 386-91.
Amdur ML.
Tellurium oxide: an animal study in acute toxicity.
Arch Ind Health 1958; 17: 665-7.
Blackadder ES, Manderson WG.
Occupational absorption of tellurium: a report of two cases.
Br J Ind Med 1975; 32: 59-61.
Cerwenka EA, Cooper WC.
Toxicology of selenium and tellurium and their compounds.
Arch Environ Health 1961; 3: 189-200.
De Meio RH.
Tellurium. II. Effect of ascorbic acid on the tellurium breath.
J Ind Hyg Toxicol 1947; 29: 393-5.
De Meio RH, O'Leary DJ.
Hemolysis by tellurium compounds: Telluride and tellurate, effect on
reduced glutathione.
J Am Osteopath Assoc 1975; 75: 430-1.
DOSE/Dictionary of substances and their effects. Vol 7.
Cambridge: Royal Society of Chemistry, 1994.
Duckett S
Fetal encephalopathy following ingestion of tellurium.
Experientia 1970; 26: 1239-41.
Gerhardsson L, Glover JR, Nordberg GF, Vouk V.
Tellurium.
In: Friberg L, Nordberg GF, Vouk VB, eds. Handbook on the toxicology
of metals. Vol 2. 2nd ed.
Amsterdam: Elsevier Science Publishers, 1986; 532-48.
Grant WM, Schuman JS.
Toxicology of the eye. 4th ed.
Illinois: Charles C Thomas, 1993.
Health and Safety Executive.
EH40/97: Occupational exposure limits 1997.
Sudbury: HSE Books, 1997.
HSDB/Hazardous Substances Data Bank.
In: Tomes plus. Environmental Health and Safety Series 1. Vol 32.
National Library of Medicine, 1997.
Kron T, Hansen C, Werner E.
Renal excretion of tellurium after peroral administration of tellurium
in different forms to healthy human volunteers.
J Trace Elem Electrolytes Health Dis 1991; 5: 239-44.
Kurantsin-Mills J, Klug RK, Lessin LS.
Irreversible erythrocyte volume expansion induced by tellurite.
Br J Haematol 1988; 70: 369-74.
Larner AJ.
How does garlic exert its hypocholesterolaemic action? The tellurium
hypothesis.
Med Hypotheses 1995; 44: 295-7.
MEDITEXT.
In: Tomes plus. Environmental Health and Safety Series 1. Vol 32.
Colorado: Micromedex, Inc., 1997.
MERCK/The Merck Index.
Tellurium hexafluoride. In: Budavari S, ed. An encyclopedia of
chemicals, drugs, and biologicals. 12th ed.
New Jersey: Merck and Co., Inc., 1996; 1560.
Müller R, Zschiesche W, Steffen HM, Schaller KH.
Tellurium-intoxication.
Klin Wochenschr 1989; 67: 1152-5.
NIOSH/NIOSH Pocket Guide.
In: Tomes plus. Environmental Health and Safety Series 1. Vol 32.
National Institute for Occupational Safety and Health (NIOSH), 1997.
Paton GR, Allison AC.
Chromosome damage in human cell cultures induced by metal salts.
Mutat Res 1972; 16: 332-6.
Reisert W.
The so-called bismuth breath.
Am J Pharm 1884; 56: 177-80.
RTECS/Registry of Toxic Effects of Chemical Substances.
In: Tomes plus. Environmental Health and Safety Series 1. Vol 32.
National Institute for Occupational Safety and Health (NIOSH), 1997.
SAX'S/Lewis RJ.
Sax's dangerous properties of industrial materials. 9th ed. Vol 3.
New York: Van Nostrand Reinhold, 1996.
Shie MD, Deeds FE.
The importance of tellurium as a health hazard in industry - a
preliminary report.
Public Health Rep 1920; 35: 939-54.
Steinberg HH, Massari SC, Miner AC, Rink R.
Industrial exposure to tellurium: atmosphere studies and clinical
evaluation.
J Ind Hyg Toxicol 1942; 24: 183-92.
See Also:
Toxicological Abbreviations