Heavy Metals Toxicity in Biological Systems

Heavy metals are chemical elements with a specific gravity greater than 5.0. Among the 90 naturally occurring elements, 21 are non-metals, 16 are light metals, and the remaining 53 are heavy metals. The majority of naturally occurring elements, which from a biological perspective is not very helpful. However, only a limited number of heavy metals are soluble under physiological conditions and bioavailable to living organisms.