Mercury

I.  Requirements

1. Based on present evidence, Hg is not considered an essential element

II.  Absorption and Metabolism

1. When taken orally, tissue concentrations of Hg are much higher when it is consumed in organic (methyl) rather than in inorganic form
   1. Absorption of inorganic Hg is less than 2%
   2. Absorption of organic forms may be as high as 95% in some species
2. Hg poisoning from absorption through the skin has been reported
3. 50% of inhaled inorganic Hg was retained by rats
4. Absorption of Hg from amalgam tooth fillings has been reported (FASEB J. 3:2641, 1989)
5. The body excretes inorganic Hg much more readily than organic Hg
6. Secretion of either inorganic or organic Hg into milk is limited
7. The placenta is a barrier against inorganic but not organic Hg
8. Apparently, the body has no homeostatic mechanisms regulating Hg concentration in tissues

III.  Sources of Hg

1. Industrial contamination
   1. Microorganisms in pond and stream sediments can methylate inorganic Hg compounds (Nature 223:753, 1969) so pollution of streams with inorganic Hg is of great concern
   2. Methylation of inorganic Hg in the rumen of cattle appears to be negligible (J. Anim. Sci. 36:415, 1973)
2. Fish
3. Hg treated seed grain used for food

IV.  Hg Toxicity

1. Chronic low level toxicity
   1. 1.          Dysfunction of the central nervous system
   2. 2.          Gingivitis
   3. 3.          Digestive upsets, loss of appetite and weight
2. Acute Hg poisoning
   1. 1.          Nausea, vomiting, abdominal pain
   2. 2.          Shock
   3. 3.          Cardiac arrhythmias
   4. 4.          Excess salivation, foul breath, loose teeth, soft spongy gums
   5. 5.          Death due to uremia
3. Maximum tolerable limit for Hg is 2 ppm for both the organic and inorganic forms

Mercury — Hg (atomic number 80)

A toxic metal. Methylmercury in some large fish is the food issue most people meet. Not a nutrient.

Vitamins, Major Elements, Trace Elements, Toxic Elements

Vitamins

Vitamin A	Vitamin B1 (Thiamin)	Vitamin B2 (Riboflavin)	Vitamin B3 (Niacin)
Vitamin B5 (Pantothenic Acid)	Vitamin B6	Vitamin B12	Vitamin C
Vitamin D	Vitamin E	Vitamin K	Biotin
Folic Acid

Major Elements

Calcium	Magnesium	Phosphorus	Sodium, Potassium, Chloride
Sulfur (Sulfer)

Trace Elements

Boron	Chromium	Cobalt	Copper
Fluorine	Iodine	Iron	Manganese
Molybdenum	Nickel (Nickle)	Selenium	Silicon
Tin	Vanadium	Zinc	Ultra Trace

Toxic Elements

Aluminum	Arsenic	Cadmium	Lead
Mercury