Heavy Metals

Arsenic is a toxic heavy metal widely distributed throughout the Earth’s crust, generally as arsenic sulphide or as metal arsenates and arsenides. Human exposure to arsenic compounds represents a major public health concern as it has been associated with a range of acute and long-term adverse health effects and diseases (WHO, 2019).

Cadmium is a toxic heavy metal which is widely distributed in the Earth’s crust (soil and rocks), air and water; however, human activity has greatly increased levels in environmental media relevant to population exposure. Human exposure to cadmium represents a major public health concern as it has been associated with a range of acute and long-term adverse health effects and diseases (WHO, 2019).

Lead is a naturally occurring highly toxic heavy metal. Its widespread use has caused extensive environmental contamination and health problems in many parts of the world. It is a cumulative toxicant that affects multiple body systems, including the neurological, haematological, gastrointestinal, cardiovascular and renal systems. Children are particularly vulnerable to the neurotoxic effects of lead, and even relatively low levels of exposure can cause serious and, in some cases, irreversible neurological damage (WHO, 2010).

Mercury is a naturally occurring element that is found in air, water and soil. Exposure to mercury – even small amounts – may cause serious health problems and is a threat to the development of the foetus in utero and for children early in life (WHO, 2017).