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Metals are the oldest toxin known to man. They are present in the rocks and ores. Rain water dissolves them and distributes them in the environment. We get exposed to them because we use them for various purposes. 

Health effects due to exposure to metals could range from skin lesions to cancer. Metals can be classified into four different groups.


Major Toxic Metals

These are the most toxic metals, which produce multiple health effects in us. Listed below are the more  important major toxic metals.

Metals Source of Exposure Health Effects
Chromium Combustion of coal and crude oil, cement manufacturing, tanning industry, toner of copying machine. Acute Effects - Dypsnea, coughing, and wheezing, skin burns, Nausea, vomiting, diarrhea.

Chronic Effects -     Bronchitis, pneumonia, asthma, nasal itching and soreness, human carcinogen

Arsenic Volcanoes, contaminated drinking water ( leaching from soil), defoliant, was used as an insecticide,  and herbicides. Acute Effects - nausea, diarrhea, abdominal pain, headache.

Chronic Effects - irritation of the skin, dermatitis, skin lesion -         hyper pigmentation, and Blackfoot disease (necrosis and gangrene). Inhalation  causes lung cancer, ingestion causes skin, bladder and liver cancer.

Lead Leaded gasoline, food and soil, toys, battery manufacturing plants Acute Effects - headache, dizziness, gastrointestinal symptoms, Death at high level of exposure.

Chronic Effects - anemia in children, behavioral and learning disabilities spontaneous abortion in pregnant women, low birth weight, hyperactive, cancer-causing agent.

Mercury Freshwater fish caught from contaminated waters, dental filling, fluorescent lights, and  thermometers, tremors, inability to walk, convulsions, and even death at high doses, emotional changes, delayed onset of walking and talking in children.


Food,  nickel containing jewelry, cooking utensils, stainless steel kitchens, and clothing fasteners, spark plugs, batteries. Acute Effects - Headache, vertigo, nausea, vomiting, insomnia, and irritability

Chronic Effects - lung and nasal cancers


Essential Metals With Toxicity Potential

These are the metals which we need for our growth and development, but become toxic when taken more than what is required.

Metals Source of Exposure Health Effects
Iron Mine, iron and steel workplace, during medical use. Acute Effects - Vomiting, and ulceration of GIT, liver damage and renal failure.

Chronic - diabetes mellitus, affects liver functions and cardiovascular effects.

Zinc Foodstuff, water, and air, galvanized cans and utensils, and plastic pipes, higher amount in seafood, meat, whole grains, dairy products, and nuts. Gastrointestinal distress and diarrhea, Inhalation could cause fever, 
Selenium Food, drinking water, metal industries, selenium-recovery processes, plastics, paints, enamels, inks, and rubber, antidandruff shampoos. Acute Effects - irritation of the mucous membranes of lungs, pulmonary edema, severe bronchitis, and bronchial pneumonia. irritation of the mucous membranes of nose and throat, producing coughing, and nosebleeds, indigestion and nausea,  headaches, dizziness, and irritation of the eyes, nausea, vomiting, diarrhea, aches, irritability, chills, and tremors.

Chronic Effects - discoloration of the skin, deformation and loss of nails, loss of hair, excessive tooth decay and discoloration, and lack of mental alertness.  


Metals with Toxicity Related to Medical Therapy

These are the metals which are used to treat a number of human ills, but they produce toxic effects when they accumulate in the body.

Metals Source of Exposure Health Effects
Aluminum Cooking utensils, used in dialysis fluid, containers. Irritated eyes, skin,  irritates the lung tissues and causes pulmonary fibrosis producing restrictive and obstructive lung diseases, affects GIT.
Gold Seawater, during medical use, industrial use. Dermatitis,  stomatitis


Minor Toxic Metals

Metals Source of Exposure Health Effects


Paints, soap, paper, and rubber, water, X-rays Gastroenteritis, muscular paralysis, lungs and causes pneumoconiosis.

Physical Hazards | Radionuclides | Metals