Description:
<jats:title>Abstract</jats:title><jats:p>Particles of white phosphorus (P<jats:sub>4</jats:sub>) in pond sediments at Eagle River Flats, Alaska, USA, a military artillery range are acutely toxic to dabbling ducks and swans. We determined if toxicity of P<jats:sub>4</jats:sub> to ducks varied by its form (i.e., dissolved or particulate) or particulate size. Residual P<jats:sub>4</jats:sub> in the digestive tracts of ducks was measured to assess risks posed to predators and scavengers of ducks. Farm‐reared mallards were treated with 12 mg P<jats:sub>4</jats:sub>/kg body weight, either dissolved in oil, or as numerous small, or one to two large particles. At the first major convulsion, ducks were euthanized and the quantity and location of P<jats:sub>4</jats:sub> in the digestive tract were determined. These data were compared to data from dead ducks collected from the artillery range. Dissolved, small, or large particles of P<jats:sub>4</jats:sub> produced similar acute toxicity. Residual P<jats:sub>4</jats:sub> in digestive tracts was greatest in ducks treated with small particles and was as great as 3.5 mg P<jats:sub>4</jats:sub>. Similar quantities of residual P<jats:sub>4</jats:sub> were found in dead ducks collected at Eagle River Flats. For dabbling ducks, P<jats:sub>4</jats:sub> particle size is not as important as the dose ingested. For predators, the P<jats:sub>4</jats:sub> contents of the entire digestive tract is important for assessment of the risk of poisoning.</jats:p>