Heavy metals are natural components of the Earth's crust. They cannot be degraded or destroyed. To a small extent they enter our bodies via food, drinking water and air. As trace elements, some heavy metals (e.g. copper, selenium, zinc) are essential to maintain the metabolism of the human body.
The related journals of heavy metals:
Journal of Environmental & Analytical Toxicology, Journal of Powder Metallurgy & Mining, Vitamins & Minerals.