text: <unk> s are<unk> s that form poisonous soluble compounds and have no biological role, i.e. are not essential minerals, or are in the wrong form. Often heavy<unk> s are thought as synonymous, but lighter<unk> s also have<unk> ity, as exemplified by beryllium, and not all heavy<unk> s are particularly<unk>  and some are even essential (such as iron). The definition may also include trace elements when considered in abnormally high,<unk>  doses. A difference is that there is no beneficial dose for a<unk>  with no biological role.<unk> s imitate the action of an essential element in the body, distorting the<unk> olic process to cause illness. Many<unk> s, particularly heavy<unk> s are<unk> , but some heavy<unk> s are essential, have a low<unk> ity, and bismuth is even non-toxic. Most often the definition includes at least cadmium, lead, mercury and the radioactive<unk> s.<unk> loids (arsenic, polonium) may be included in the definition. Radioactive<unk> s have both radiation<unk> ity and chemical<unk> ity.<unk> s in an oxidation state abnormal to the body may also become<unk> : chromium(III) is an essential trace element, but chromium(VI) is a carcinogen.
  The<unk> ity is a function of solubility, so that as insoluble salts or even in the<unk> lic form,<unk> s may have negligible<unk> ity. On the other hand, organometallic forms, such as dimethyl mercury and tetraethyl lead, are extremely<unk> .<unk> s bioaccumulate in the body and in the food chain. The exceptions are barium and aluminum. Therefore, a common characteristic of<unk> s is the chronic nature of their<unk> ity.<unk> s:
  Barium
  Beryllium
  Aluminum
  Cadmium
  Lead - lead poisoning
  Mercury - mercury poisoning
  Thallium
  Antimony
  Radioactive<unk> s:
  Thorium
  Uranium
  The transuraniums, such as plutonium, americium, etc.
  Polonium (a<unk> loid)
  Radioactive isotopes of lighter elements, e.g. cobalt-60.
  Arsenic (see arsenic poisoning) is a<unk> loid.
  Thorium
  Uranium
  The transuraniums, such as plutonium, americium, etc.
  Polonium (a<unk> loid)
  Radioactive isotopes of lighter elements, e.g. cobalt-60.
  Trace elements with<unk> ity:
  Chromium as hexavalent Cr(VI)
  Nickel
  Copper
  Iron
option_0: Toxic metal
option_1: Hazardous drugs
option_2: Food additive
option_3: Metal
option_4: Counterfeit drug
option_5: Marine toxins
option_6: Alcohol
option_7: Inhalant