Zinc Phosphide Residues in Gray-Tailed Voles (Microtus canicaudus) Fed Fixed Particles of a 2% Grain Bait

This study measured depelted-carcass residues of zinc phosphide (Zn,P,, CAS # 1314-84-7) in 8 (43 and 49) gray-tailed voles (Microtus canicaudus). Six (3$ 39) voles were confined individually in 1.89 dkl(5 gal) plastic pails that contained 5,2% Zn,P2 steamrolled-oat (SRO) groats; 2 voles ( Id and 19) served as analytical (unbaited) controls. Four test voles (3-3 19) died within 7.5 h after bait exposure; whereas, 2 test voles showed no signs of toxicosis and were euthanized 7.0 h after bait exposure. Whole carcasses were stored frozen and depelted carcasses were analyzed within 3 1 days for Zn3P2 residues using a acid-hydrolyzation, gas-chromatographic (GC) method. Analytical controls were euthanized, with carcasses stored and analyzed the same as test voles. A mean ( f SD) 4.7 (k0.8) SRO groats were consumed by the test voles; this converted to a mean (kSD) intake of 2.15 (k0.38) mg Zn,P, and dose of 73.25 mg/kg ( k 22.95) Zn3P2. The mean ($ SD) Zn,P2 residue in the 6 test vole carcasses was 0.42 mg ( f 0.68); control carcasses contained <0.009mg Zn,P2- 20 mg/kg) required to affect these species. Published by Elsevier Science Ltd.