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From 2014.igem.org

Background / Heavy metals – topical and ubiquitous

In today’s world, heavy metals are the indispensable basis for the technical progress of our society. They allow us to refine raw materials to improve the infrastructure (copper, zinc), keep us mobile (copper, zinc) and ensure energy is always available from rechargeable batteries (cadmium) and in the form of electricity (copper). The mining industry has grown considerably and the mining of heavy metals has increased dramatically since the Industrial Revolution in the 19th century. This is down to the increase in global demand as well as to new extraction technologies. But what is the real price we have to pay for heavy metals?

In nature, heavy metal ions are usually found in complex compounds. The process of mining for gold, lead or copper brings these ions together with large quantities of their toxic ligands, arsenic, for example, to the surface, where they are temporarily stored on slag heaps. Heavy metals are released by corrosion and the extremely high wear and tear suffered by products containing heavy metals (especially in the electronics and automotive industry). They are also mobilized by weathering processes, and then transported from the slag heaps at the mines into our groundwater. From there they get into our drinking water and via agricultural processes they indirectly get into our food chain. Heavy metals can accumulate in the tissues in the body and even very low concentrations can severely harm our health by causing organ failure, infertility or neuronal degeneration. The heavy metal load is a global problem. Although the heavy metal load in newly industrialized countries such as China or Bangladesh is much higher than in Germany, there are many possible applications for our project at home as well. Brake wear and tire abrasion release large quantities of zinc and copper onto German roads every day. The rain washes these heavy metals onto the grass verges and water retention basins adjoining the ‘autobahns’ or they enter the surrounding lakes and rivers via the municipal sewerage systems.