In its metallic form, gold is not toxic, so we can eat ice cream with gold flakes. However, some natural gold compounds break down in the body and release gold ions, which can have toxic effects on living organisms. The same is true for copper, but bacteria have another way of eliminating the extra copper. Gold is omnipresent in the human environment and most people come into contact with it through the use of jewelry, dental devices, implants or treatments for rheumatoid arthritis.
Gold isn't a nutrient, but people are exposed to it as a food coloring and in food chains. This review analyzes the dangers faced by the personal and domestic use of gold and the much greater risks posed by occupational exposure to metal in the extraction and processing of gold ores. In the latter situation, regular manual contact or inhalation of toxic or carcinogenic materials such as mercury or arsenic, respectively, presents a much greater danger and greatly complicates the assessment of the toxicity of gold. The uses and risks presented by new technologies and the use of nanoparticulate gold in cancer therapies and diagnostic medicine constitute an important consideration in the toxicity of gold, in which tissue absorption and distribution are largely determined by particle size and surface characteristics.
Many human problems arise due to the ability of metallic gold to induce allergic contact hypersensitivity. While gold in jewelry can cause allergic reactions, other metals such as nickel, chromium and copper found in white gold or alloys present more serious clinical problems. It is concluded that the toxic risks associated with gold are low in relation to the wide range of possible routes of exposure to the metal in everyday life. Today's hard rock mining industry spills cyanide all too often, endangering the environment, wildlife and humans.
Mercury is a shiny liquid metal that attacks the nervous system. Exposure can cause lifelong disability and is particularly harmful to children. At higher doses, mercury can kill. Its most important use worldwide is in small-scale gold mining.