A metallic element of atomic number 30 and atomic weight 65.38. It is a necessary trace element in the diet, forming an essential part of many enzymes, and playing an important role in protein synthesis and in cell division. Zinc deficiency is associated with anemia, short stature, hypogonadism, impaired wound healing, and geophagia. It is known by the symbol Zn.
belongs to the class of inorganic compounds known as homogeneous transition metal compounds. These are inorganic compounds containing only metal atoms,with the largest atom being a transition metal atom.
Excessive zinc intake alters copper and iron absorption, most likely through competitive binding in intestinal mucosal cells. Stomach acid dissolves metallic zinc, producing zinc chloride, which is a corrosive product damaging the stomach lining. Metal fume fever is thought to be an immune response to inhaled zinc. (2, 3, 1)
Metabolism
Zinc enters the body through the lungs, skin, and gastrointestinal tract. Intestinal absorption of zinc is controlled by zinc carrier protein CRIP and metallothioneins. Zinc is widely distributed in tissues and tissues fluids, and concentrated in the liver, gastrointestinal tract, kidney, skin, lung, brain, heart, and pancreas. Zinc binds to carbonic anhydrase in erythrocytes, and to albumin, α2-macroglobulin, and amino acids in the the plasma. Albumin and amino acid bound zinc can diffuse across tissue membranes. Zinc is excreted in the urine and faeces. (3)
No indication of carcinogenicity to humans (not listed by IARC).
Uses/Sources
Zinc has many commercial uses as coatings to prevent rust, in dry cell batteries, and can be mixed with other metals to produce alloys such as brass and bronze. Zinc compounds are widely used in industry to make paint, rubber, dyes, wood preservatives, and ointments. (3)
Chronic exposure to zinc causes anemia, atazia, lethargy, and decreases the level of HDL (good) cholesterol in the body. It is also believed to cause pancreatic and reproductive damages. Unbalanced levels of copper and zinc binding to Cu,Zn-superoxide dismutase have been linked to amyotrophic lateral sclerosis (ALS). (3)
Symptoms
Ingestion of large doses of zinc causes stomach cramps, nausea, and vomiting. Acute inhalation of large amounts of zinc causes metal fume fever, which is characterized by chills, fever, headache, weakness, dryness of the nose and throat, chest pain, and coughing. Dermal contact with zinc results in skin irritation. (3)
Treatment
Zinc poisoning is treated symptomatically, often by administering fluids such as water or milk, or with gastric lavage. (3)
