Metal Toxicity – An Introduction

Abstract

Both essential and non-essential metal ions can cause toxicity. The essential metal ions for humans are the bulk metals sodium, potassium, calcium and magnesium and the trace metals manganese, iron, cobalt, copper, zinc and molybdenum, and, after outlining why they are required, we summarise the circumstances in which certain of them can be toxic. A number of non-essential metals, like cadmium, lead and mercury are not at all necessary for life but, when introduced into the human environment, they pose serious problems on account of their toxicity. Essential metal ion toxicity can be attributed to accumulation of excessive concentrations of the metal ion, often in specific tissues or organs. The toxicity of non-essential metal ions is a consequence of environmental exposure leading to their accumulation within the body, where they interfere with the functions of the essential metal ions. Both types of metal toxicity can, in principle, be treated by the use of appropriate metal ion chelators.