TOXICOLOGY OF WHITE PHOSPHORUS (P-4) TO DUCKS AND RISK FOR THEIR PREDATORS - EFFECTS OF PARTICLE-SIZE

Particles of white phosphorus (P-4) in pond sediments at Eagle River F lats, Alaska, USA, a military artillery range are acutely toxic to dab bling ducks and swans. We determined if toxicity of P-4 to ducks varie d by its form (i.e., dissolved or particulate) or particulate size. Re sidual P-4 in the digestive tracts of ducks was measured to assess ris ks posed to predators and scavengers of ducks. Farm-reared mallards we re treated with 12 mg P-4/kg body weight, either dissolved in oil, or as numerous small, or one to two large particles. At the first major c onvulsion, ducks were euthanized and the quantity and location of P-4 in the digestive tract were determined. These data were compared to da ta from dead ducks collected from the artillery range. Dissolved, smal l, or large particles of P-4 produced similar acute toxicity. Residual P-4 in digestive tracts was greatest in ducks treated with small part icles and was as great as 3.5 mg P-4. Similar quantities of residual P -4 were found in dead ducks collected at Eagle River Flats. For dabbli ng ducks, P-4 particle size is not as important as the dose ingested. For predators, the P-4 contents of the entire digestive tract is impor tant for assessment of the risk of poisoning.