Teratogenicity mercury

FAS is normally characterized by growth retardation, anomalies of the head and face, and psychomotor dysfunctions. Excessive consumption of ethyl alcohol may lead to malformations of the heart, extremities, and kidneys. Since consumption of ethyl alcohol is socially acceptable and prevalent even in pregnant women, the risks associated with the use of ethyl alcohol are remarkable. However, it should be kept in mind that there are several chemical compounds in tlie occupational environment that may also cause malformations even at low doses. The oc-cupationally-important known human teratogens include methyl mercury, ethyl alcohol, PCB compounds, tobacco smoke, lead, TCDD, 2,4,5- F, carbon monoxide, nitrogen dioxide, gasoline, and fluoride. 

Mercury is a mutagen, teratogen, and carcinogen, and causes embryocidal, cytochemical, and histopathological effects... 

Hoffman, D.J. and J.M. Moore. 1979. Teratogenic effects of external egg applications of methyl mercury in the mallard, Anas platyrhynchos. Teratology 20 453-462. 

Khera, K.S. 1979. Teratogenic and genetic effects of mercury toxicity. Pages 501-518 in J.O. Nriagu (ed.). The Biogeochemistry of Mercury in the Environment. Elsevier/North-Holland Biomedical Press, NY. 

Most cases of mercury poisoning led to handicap, chronic disease, or death. The most frequent symptoms include numbness of limbs, lips and tongue, speech abnormalities, limb function disorders, visual acuity disorders, deafness, and muscular atrophy. Insomnia, hyperactivity, and coma have also been reported. Methylmercury penetrates the blood-brain barrier and causes central nervous system injuries. Mercury also has a teratogenic effect, leading to congenital abnormalities or congenital Minamata disease. 

In addition to teratogenicity, mercury has been associated with decreased reproductive performance in quail (123) and lead with neuro-pathological changes in the suckling rat (124). Both inorganic and organic mercury are excreted into the milk with equal ease (121). Fluoride is known to be excreted by the lactating breast as well (78). 

Table 1 lists two common metals, lead and mercury. The highly teratogenic organic compounds of these metals are not ordinarily handled in the undergraduate laboratory. Inorganic salts of lead and mercury are discussed in the next section. It is only the free elements that are addressed here. 

The inorganic compounds in Table 1 include arsenic compounds, cadmium sa1ts lead chloride, lead nitrate, and mercury salts. These are highly poisonous compounds as well as being suspected teratogens, and they need to be handled with extra care. Fortunately, most of these substances are used only in dilute solution and usually in semi-micro quantities. Solutions of arsenic, cadmium, lead, and mercury salts are typically used in connection with Qualitative Analysis procedures, and the amounts used are often no more than a few drops. Hand washing at the end of the laboratory period is especially important after working with solutions such as these. 

Several studies indicate that different methods cause adverse effects to embryonic and fetal tissues and eventually lead to the development of teratogenic effects. Metals are omnipresent in the living environment. A variety of anthropogenic activities (e.g., smelting metallic ore, industrial and metal fabrication, commercial application, burning of fossil fuels) have caused adverse effects to the developing fetus. In fact, notorious elements, such as cadmium, lead, and mercury, have been associated with injury and malformation to the growing embryo and fetus of animals and humans.65... 

One of the particularly tragic aspects of the Minamata disaster was the effect methyl mercury exposure had on unborn children. Some of the mothers exposed to methyl mercury from the fish and seafood gave birth to babies who were severely affected with a disorder similar to infantile paralysis, suffering cerebral palsy and mental retardation. This occurred even in mothers who showed no symptoms themselves, a classic characteristic of a teratogen. Some babies were born completely paralysed. 

DOT CLASSIFICATION 6.1 Label Poison SAFETY PROFILE Poison by ingestion, intravenous, intraperitoneal, subcutaneous, and possibly other routes. An experimental teratogen. Other experimental reproductive effects. Mutation data reported. See also MERCURY COMPOUNDS. When heated to decomposition it emits toxic fumes of Hg. 

DFG MAK Confirmed Animal Carcinogen with Unknown Relevance to Humans SAFETY PROFILE A deadly human poison by inhalation. Poison by ingestion and intraperitoneal routes. An experimental teratogen. See also MERCURY COMPOUNDS, ORGANIC. Flammable when exposed to heat or flame can react with oxidizing materials. When heated to decomposition or on contact with acid or acid fumes it emits highly toxic fumes of... 

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