When introducing new chemicals into the environment,
it is pertinent that short- and long-term environmental
and health risk factors are well understood and evaluated. It is thought that certain metals, even in low
concentrations, when released into the environment,
may exert toxicity to living organisms over a very long
time (Nriaguand Pacyna, 1988). A typical example of
the enormity of the public health consequences generated
by a single toxic metal is exposure to anthropogenic
lead. Although its removal from petrol in developed
countries significantly reduced overall levels of exposure,
it did not remove lead from the environment
altogether and the hazard of persistent long-term lead
exposure continues to exist.