BlessWorld Foundation International

Affecting the World Through Health
A Global Health Initiative

Toxic Metal Exposure: A Public Health Concern



Heavy metals are dense metals that are found naturally in the earth. The major heavy metals of public health concern are lead, mercury, cadmium and arsenic which are all included in World Health Organization’s list of 10 chemicals of public health concern. These metals are quite toxic to the human body as there are no known safe levels in humans or other species. This propensity to harm not just humans, but to accumulate in plants, fishes and soil poses great risks to potentially compromise the ecosystem. Despite being harmful, these chemicals have been found to be useful in several ways which include:

  • Lead-As an additive in petrol which has been phased out by most countries, use in certain folk medicines, lead based paints and lead solder for canning
  • Mercury-use in electrical equipment, thermometers, pharmaceuticals, thimerosal which has been removed from most vaccines, dental amalgam and use in artisan gold mining which has drawn recent attention of the UN
  • Arsenic-widespread use as components of pharmaceuticals and semiconductors
  • Cadmium-used in batteries and fertilizers

Cigarette smoking is an important source of exposure to some chemicals thus leading to ease of exposure. In addition, poor disposal of these substances either by dumping on land or rivers- especially ones used by communities can result in devastating effects to a population. Take the Minamata disease catastrophe that happened in japan in the 1950s as an example: more than 600 people died (not including the thousands with disabilities) from dumping of mercury wastes in Minamata bay by a chemical factory. It is sad that despite the disasters that have been caused by heavy metal exposures, it is still a largely neglected public health problem. It is worthy to mention that there are dangerous and life threatening levels of these metals in Tasmanian lakes of Australia, Kurang river in Pakistan, Shur river in Iran, Ganges delta in India and Bangladesh and many others.

Some of the oldest diseases of human can be traced to heavy metal poisoning associated with mining, refining and use. They cause disease primarily by inhibiting important enzymes in the body. It can either be acute due to eating or inhalation of high levels of these metals usually leading to death or a chronic accumulation from continuous exposure resulting in disabilities. This leads to neurological problems as in the Minamata disease discussed and other clinical manifestations. Importantly, they are associated with increased carcinogenic and teratogenic risk.

The clinical treatment of giving chelators is obviously not sufficient to address this problem (as clinical solutions are not public health solutions).Even though clinicians have an important role as part of the surveillance system, what is needed is remove the source of exposure just like the great Doctor, John snow. Many organisations like the EPA, WHO, UN and others have to work with governments and health agencies to ensure minimal exposure to these chemical by regulating their use and enforcing proper disposal. There should be continuous research in the use of associated products by the general public to monitor and report any adverse effects.

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