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DermNet NZ


Facts about the skin from DermNet New Zealand Trust. Topic index: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z


Heavy metal toxicity

Heavy metals are chemical elements that are commonly found in our environment. Without realising it all people are exposed to heavy metals on a daily basis. However, the quantities that we inhale, ingest or come into contact with the skin are so small that they are usually harmless. In fact, small amounts of some heavy metals in our diet are essential to good health. These are referred to as trace elements and include iron, copper, manganese, zinc, plus others, which are commonly found naturally in fruits and vegetables.

Toxic heavy metals and routes of exposure

Toxic heavy metals are heavy metals that become poisonous to the body when they are not metabolised or excreted and so accumulate in organs and tissues. They enter the human body through food, water, air, or absorption through the skin. Routes of exposure are described below.

Heavy metal Potential sources for exposure
Arsenic
  • Smelting process of copper, zinc and lead
  • Manufacture of chemicals and glass
  • Pesticides, fungicides, paints, rat poison, wood preservatives
Lead
  • Pipes, drains and soldering materials
  • Old lead-based painted houses and furniture that has started to flake, chip, chalk and dust
  • Battery manufacture
  • Fuel additives, PVC plastics, crystal glass production, pencils and pesticides
Mercury
  • Mining operations, chloralkali plants, paper industries
  • Thermometers, dental amalgam (fillings), vaccines
Cadmium
  • Mining and smelting of lead and zinc
  • Nickel-cadmium batteries, PVC plastics, paint pigments
  • Insecticides, fungicides, sludge and fertilizers
Silver
  • Silver mining, refining, silverware and metal alloy manufacturing, metallic films on glass electroplating solutions, photographic processing
  • Colloidal silver dietary supplements, silver salts in nasal/eye drops, irrigations and wound dressings
Iron
  • Dietary iron supplements
  • Drinking water, iron pipes and cookware
Gold

Signs and symptoms of heavy metal toxicity

Signs and symptoms of toxicity depend on the heavy metal involved and whether exposure causes acute toxicity or chronic and subtle effects.

Signs and symptoms of acute toxicity Signs and symptoms of chronic exposure
  • Severe, rapid in onset
  • Cramping, nausea, vomiting, pain
  • Breathing difficulties
  • Sweating
  • Headaches
  • Convulsions
  • Skin rash
  • Develop slowly over months or years
  • Skin changes
  • Impaired cognitive, motor and language skills
  • Nausea, lethargy, malaise
  • Insomnia
  • Emotional instability

The heavy metals that cause the most significant skin changes and are discussed in more detail include arsenic, silver, gold and mercury.

Related information

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Author: Vanessa Ngan, staff writer

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If you have any concerns with your skin or its treatment, see a dermatologist for advice.