ABSTRACT
Metals and their compounds are ubiquitous in the environment, on the earth’s
surface and underground. Those which are water soluble are constantly
dissolved by atmospheric factors (precipitation, run-off) and by hydrothermal,
subterranean currents; they are ultimately transported into the vast bodies of
water of the seas and lakes and thus removed from significant human contact.
Those which remain in the lithosphere are relatively harmless due to their low
solubility and thus bioavailability. In contrast it is the anthropogenic forms of
many metals which pose an increasing threat to living organisms. Generated
