A 30-day toxicity test was made to determine the relative toxicity of lead, a tin-lead alloy, zinc, nickel, teflon-coated steel, and tin, all in shot form, to pen-reared mallard drakes. All of the 15 ducks dosed with lead died. Twenty-seven percent of 15 dosed with alloy, and 20 percent of 15 dosed with zinc also died. Ten of the remaining zinc-dosed ducks showed signs of distress, including losses of muscular control and body weight. There were no deaths among 15 ducks dosed with nickel, 15 dosed with teflon-coated steel, and 15 dosed with tin. Seventy-three percent of those dosed with nickel shot eliminated all shot before the end of the 30-day period. Acid-fast intranuclear inclusion bodies were present in the kidneys of mallards dosed with commercial lead shot, or with tin-lead alloy shot, but not in the kidneys of birds given nickel, tin, or teflon-coated steel shot. Atypical, pale, acid-fast bodies were found in kidneys of 1 of 15 birds dosed with zinc. An iron-containing pigment, which stained positive with the Prussian blue technique, was present in variable amounts in almost all livers. Zinc-dosed ducks that died or were killed while still showing signs of zinc intoxication had higher iron levels in the liver than ducks that had recovered from zinc intoxication.
