If urinary
cadmium provides a reliable measure of
the cumulative dose of cadmium
absorbed by the lungs and gut, and if
cadmium delivered to the lungs through
the circulation is as hazardous as
cadmium delivered in inspired air, these
observations imply a ‘‘dose’’ threshold
for inducing emphysema that is similar
to, or only marginally above, the average
dose retained without apparent ill effect
in the population at large from food and
water.