Toxicology of white phosphorus (P4) to ducks and risk for their predators: Effects of particle size

Abstract

Abstract Particles of white phosphorus (P4) 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 P4 to ducks varied by its form (i.e., dissolved or particulate) or particulate size. Residual P4 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 P4/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 P4 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 P4 produced similar acute toxicity. Residual P4 in digestive tracts was greatest in ducks treated with small particles and was as great as 3.5 mg P4. Similar quantities of residual P4 were found in dead ducks collected at Eagle River Flats. For dabbling ducks, P4 particle size is not as important as the dose ingested. For predators, the P4 contents of the entire digestive tract is important for assessment of the risk of poisoning.