MERCURY

Uses:  thermometers, felt, paints, explosives, lamps, electrical 
apparatus, batteries.  Organic mercury compounds are used in 
treating seeds.  Formerly used medicinally and for brine conver-
sion to chlorine.
Fatal dose:  mercuric chloride fatal dose is 1g.  Monatomic 
mercury vapor is lipophilic, and is usually transferred to brain 
cells, is oxidized to Hg(2+), and causes toxic effects.  Monatomic 
mercury exposure limit is .01 mg/m3.
Acute toxic effects:  abdominal pain, vomiting, diarrhea, uremia.
Necrotizing bronchioloitis, pneumonitis, pulmonary edema, pnuemo-
thorax.  Acidosis and renal failure.
Chronic toxic effects:  Central nervous system damage, tremors, 
headache, depressions, insomnia, hallucination, mental deteriora-
tion, anorexia, pain and numbness, restlessness.
Teratogenesis: demonstrated for from mercury poisoning from 
eating mercury-contaminated fish.
Carcinogenicity: [not mentioned]

Source:  Robert Dreisbach and William Robertson, "Handbook of 
Poisoning:  Prevention, Diagnosis and Treatment," Twelfth Edi-
tion, (Los Altos:  Appleton and Lange, 1987).

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                  REPRODUCTIVE TOXICITY REVIEW  
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** DIMETHYL MERCURY                      ** CAS #:   593-74-8   ** SCREEN NO.  1 
                                                                              
     Mercury has had a long history as a potential reproductive               
toxin.  It was noted many years ago that pregnant women treated with          
mercurials had a high incidence of spontaneous abortion (1).  More            
recent mercury effects became publicized after an outbreak of                 
cerebral palsy and microcephaly in the fishing village of Minimata,           
Japan (2,3).  This was related to methyl mercury contamination of             
the fish eaten by the population.  A similar incident involved the            
poisoning of an Iraqi population with methyl mercury contaminated             
grain (4,5).  In this population infants exposed in utero                     
demonstrated psychomotor retardation and cerebral palsy.  Similar             
congenital neurological disease has been reported in other instances          
of methyl mercury food contamination (6,16).  Experimental animal             
models of organic mercury embryotoxicity show a number of induced             
birth defects but neurologic effects are generally consistent with            
the human experience (10-16,19).                                              
     The marked potential for reproductive toxicity of organic                
mercurials such as methylmercury does not appear to apply to                  
inorganic mercury.  Inorganic mercury does not cross the placenta             
well.  Dental personnel working with mercury-containing amalgams may          
be exposed to considerable mercury vapor which is well-absorbed by            
the adult.  In spite of poor placental passage, one study found               
levels of mercury in the placentae and fetal membranes of exposed             
pregnancies in dental assistants to be about twice those of                   
nonexposed controls (7).  There have not, to our knowledge, been              
reports documenting a mercury-associated increase in birth defects            
or neurological sequelae in the offspring of dental assistants.  One          
study in Denmark (8) also failed to show an increase in spontaneous           
abortions among dental assistants compared to a control population.           
Inorganic mercurial ointments, such as red or yellow mercuric oxide,          
may also be associated with the topical absorption of significant             
amounts of mercury (9).  We have not identified any reports on                
possible adverse human reproductive effects from mercury absorbed in          
this manner.                                                                  
                                                                              
     Pregnant rodents exposed to very high concentrations of mercury          
vapor or fed inorganic mercurials show an increase in stillbirths,            
congenital anomalies, and neonatal mortality in their offspring               
(17,18).  Teratogenic effects are generally minor and may be                  
attributable to general maternal or fetal toxicity rather than to a           
specific defect in organogenesis.                                             
                                                                              
     Safe levels of mercury during pregnancy have not been                    
established although suggested guidelines are that environments have          
a mercury vapor concentration less than 0.01 mg/m3.  Organic                  
mercurials should be avoided entirely and some authorities have               
suggested limiting the intake of fish to no more than 350 g/week              
(16).                                                                         
                                                                              
SELECTED REFERENCES                                                           
                                                                              
 1. Alfonso J, DeAlvarez R: Effects of mercury on human gestation.            
    Am J Obstet Gynecol 80:145-54, 1960.                                      
                                                                              
 2. Matsumoto H et al: Fetal Minimata disease. J Neuropath Exp                
    Neurol 24:563-74, 1965.                                                   
                                                                              
 3. Muramaki U: The effect of organic mercury on intrauterine life.           
    Acta Exp Biol Med Biol 27:301-36, 1972.                                   
                                                                              
 4. Marsh DO et al: Fetal methylmercury poisoning: Clinical and               
    toxicological data on 29 cases. Ann Neurol 7:348-53, 1980.                
                                                                              
 5. Amin-Zaki L et al: Perinatal methylmercury poisoning in Iraq. Am          
    J Dis Child 130:1070-6, 1976.                                             
                                                                              
 6. Snyder RD: Congenital mercury poisoning. N Engl J Med                     
    284:1014-6, 1971.                                                         
                                                                              
 7. Wannag A, Skejerasen J: Mercury accumulation in placenta and              
    fetal membranes. A study of dental workers and their babies.              
    Environ Physiol Biochem 5:348-52, 1975.                                   
                                                                              
 8. Heidam LZ: Spontaneous abortions among dental assistants,                 
    factory workers, painters, and gardening workers: a follow up             
    study. J Epidemiol Commun Health 38:149-55, 1984.                         
                                                                              
 9. De Bont B et al: Yellow mercuric oxide ointment and mercury               
    intoxication. Eur J Pediatr 145:217-8, 1986.                              
                                                                              
10. Chen W et al: Some effects of continuous low-dose congenital              
    exposure to methylmercury on organ growth in the rat fetus.               
    Teratology 20:31-6, 1979.                                                 
11. Fuyuta M et al: Embryotoxic effects of methylmercury chloride             
    administered to mice and rats during organogenesis. Teratology            
    18:353-66, 1978.                                                          
                                                                              
12. Fuyuta M et al: Teratogenic effects of a single oral                      
    administration of methyl mercuric chloride in mice. Acta Anat             
    104:356-62, 1979.                                                         
                                                                              
13. Harris SB et al: Embryotoxicity of methylmercuric chloride in             
    golden hamsters. Teratology 6:139-42, 1972.                               
                                                                              
14. Khera KS, Tabacover SA: Effects of methylmercuric chloride on             
    the progeny of mice and rats treated before or during gestation.          
    Food Cosmet Toxicol 11:245-54, 1973.                                      
                                                                              
15. Spyker JM, Smithberg M: Effects of methylmercury on prenatal              
    development in mice. Teratology 5:181-90, 1972.                           

16. Koos BJ, Longo LD: Mercury toxicity in the pregnant woman,                
    fetus, and newborn infant. Am J Obstet Gynecol 126:390-409,               
    1976.                                                                     
Š                                                                              
17. Grin NV et al: State of the reproductive function of animals              
    during continuous inhalation of a mixture of mercury-containing           
    salts. Gig Sanit (10):88-90, 1981.                                        
                                                                              
18. Berg GC: Toxicity of mercuric oxide to pregnant mice and the              
    mechanism of resistance of prenatally exposed litters                     
    (abstract). Teratology 26:46A, 1982.                                      
                                                                              
19. Su M, Okita G: Embryocidal and teratogenic effects of                     
    methylmercury in mice. Toxicol Appl Pharmacol 38:207-16, 1976.