Lead toxicity.

• Author: Ceartas, Devin M.
• Position: Lead: The Poisoning Continues - Disease/Disorder overview

Having lead in your body is like putting a CD-ROM in your DVD recorder--the shapes are similar but they don't work the same. Lead, in the form in which it affects biological systems, has the same +2 charge and roughly the same size as calcium ions. Lead ions are also similar to zinc and iron ions. Lead ions take the place of calcium, zinc and iron ions in many overlapping biochemical pathways. By substituting for essential minerals, lead can do permanent and severe damage to humans and other animals.

Because it is an element, lead does not degrade or lose its toxic effect over time. Being toxic on such a basic level, it is important to note that there is no known level at which lead is safe. [1] There is no chemical or biological reason to expect there to be a safe level of lead.

Greek physician Dioscorides is quoted as saying that lead makes the "mind give way" as long ago as the second century BCE. [2] It is clear that lead has a disruptive effect on the ability of cells in the brain and other parts of the nervous system to send and receive information.

Calcium ions play a critical role in this process, as an internal signal causing nerve cells to release chemicals known as neurotransmitters which carry signals between nerve cells. Researchers believe that early childhood brain activity builds pathways which lead to the development of mental abilities. The effect on this process appears to be one reason children exposed to even minute amounts of lead can suffer permanent negative effects to their reasoning and behavioral skills. [3] Lead has it's strongest effects on children under the age of six.

Enzymes make many critical biochemical pathways possible, such as the conversion of food into energy and the cells needed for growth. Lead ions can substitute for iron, zinc or other metal ions in the chemically active core of several enzymes, blocking the functioning of the enzyme.

Lead could bind to naturally occurring RNA creating an enzyme-like activation for the cutting of chemical bonds in other RNA strands, thus destroying them. [4] The primary role of RNA is in taking genetic messages from cellular DNA to the parts of the cell which make enzymes and other protein molecules.

Lead is known to disrupt the normal biochemistry in the kidney, brain and bones by causing the excessive production of some proteins whose role is to bind specifically to other molecules. [5]

Amino acids and other small molecules are converted to glucose sugar in the...