Steel shot is required for waterfowl hunting in the United States, but
hunter dissatisfaction with steel's perceived ballistic performance h
as reduced compliance with steel shot laws, contributed to the loss of
waterfowl hunters nationwide, and renewed interest in an alternative
non-toxic shot with ballistic qualities similar to lead shot. We evalu
ated the acute toxicity of an alternative shot by orally dosing 20 8-w
eek-old game farm mallards (Anas platyrhynchos) with 12-17 pellets (xB
AR = 1.03 g) composed of tungsten, bismuth, and tin (TBT). Ducks were
monitored for 32 days for evidence of intoxication. Eroded shot eviden
t in radiographs taken 11 days post-dosing indicated acute exposure to
the constituent metals, but no dosed or undosed birds died during the
trial. Behavior of dosed and undosed ducks (both n = 20) was normal t
hroughout the trial, and no differences were detected in food consumpt
ion (P = 0.52, beta = 0.39) or body mass change (P = 0.71, beta = 0. 1
5) relative to treatment. Except for blood calcium, none of 24 hematol
ogy or blood chemistry variables measured 3. 11, 21, and 32 days post-
dosing differed (P greater-than-or-equal-to 0.09, beta = 0.16) between
dosed and undosed birds. Differences in blood calcium (P = 0.02, beta
= 0.12) were judged to be unrelated to shot exposure. No gross lesion
s were observed during postmortem examinations, nor did histopathologi
cal examinations reveal any evidence of toxicity or tissue damage. Tin
and tungsten were not detectable (<6 ppm) in kidney or liver samples.
Bismuth concentrations in kidney and liver (< 16 ppm) were near detec
table limits and did not differ (P = 0.34 and P = 0.22, respectively)
between dosed and undosed ducks. We conclude that TBT shot presents vi
rtually no potential for acute intoxication in mallards under the cond
itions of our study.