Public health aspects of toxic heavy metals in animal feeds.

Studies involving animals of three species (dairy cattle, growing swine, and laying chickens) indicated that residues of lead and cadmium do not increase appreciably in major food products obtained from the animals during long-term exposure to subtoxic dietary concentrations of these heavy metals. Human risk would not be expected by the consumption of milk, meat, or eggs from animals similarly exposed. Both metals accumulate in liver and kidney, and lead accumulates in bone. A moderate intake of liver and kidney from lead-exposed animals appears to present little or no health hazard. Utilization of these organs from cadmium-exposed animals, however, should be avoided.