[Federal Register Volume 59, Number 7 (Tuesday, January 11, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-536]


[[Page Unknown]]

[Federal Register: January 11, 1994]


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DEPARTMENT OF HEALTH AND HUMAN SERVICES
 

National Toxicology Program; Availability of Technical Report on 
Toxicology and Carcinogenesis Studies of Mercuric Chloride

    The HHS' National Toxicology Program announces the availability of 
the NTP Technical Report on the toxicology and carcinogenesis studies 
of Mercuric Chloride, an inorganic compound that has been used in 
agriculture as a fungicide, in medicine as a topical antiseptic and 
disinfectant, and in chemistry as an intermediate in the production of 
other mercury compounds.
    Two-year toxicology and carcinogenicity studies were conducted by 
administering to groups of 60 rats of each sex 0, 2.5, or 5 mg mercuric 
chloride/kg body weight and to groups of 60 mice of each sex 0, 5, or 
10 mg/kg in deionized water by gavage 5 days per week for 2 years.
    Under the conditions of these 2-year gavage studies, there was some 
evidence of carcinogenic activity\1\ of mercuric chloride in male F344 
rats based on the increased incidence of squamous cell papillomas of 
the forestomach. Marginally increased incidences of thyroid follicular 
cell adenomas and carcinomas may have been related to mercuric chloride 
exposure. There was equivocal evidence of carcinogenic activity of 
mercuric chloride in female F344 rats based on two squamous cell 
papillomas of the forestomach. There was equivocal evidence of 
carcinogenic activity of mercuric chloride in male B6C3F1 mice based on 
the occurrences of two renal tubule adenomas and one renal tubule 
adenocarcinoma. There was no evidence of carcinogenic activity of 
mercuric chloride in female B6C3F1 mice receiving 5 or 10 mg/kg.
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    \1\The NTP uses five categories of evidence of carcinogenic 
activity observed in each animal study: Two categories for positive 
results (``clear evidence'' and ``some evidence''), one category for 
uncertain findings (``equivocal evidence''), one category for no 
observable effect (``no evidence''), and one category for studies 
that cannot be evaluated because of major flaws (``inadequate 
study'').
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    Questions or comments about the Technical Report should be directed 
to Central Data Management at P.O. Box 12233, Research Triangle Park, 
NC 27709 or telephone (919) 541-3419.
    Copies of Toxicology and Carcinogenesis Studies of Mercuric 
Chloride (CAS No. 7487-94-7) in F344/N Rats and B6C3F1 Mice (Gavage 
Studies) (TR-408) are available without charge from Central Data 
Management, NIEHS, MD A0-01, P.O. Box 12233, Research Triangle Park, NC 
27709; telephone (919) 541-3419.

    Dated: January 3, 1994.
Kenneth Olden,
Director, National Toxicology Program.
[FR Doc. 94-536 Filed 1-10-94; 8:45 am]
BILLING CODE 4140-01-M