Three plutonium chelation cases at Los Alamos National Laboratory.

Chelation treatments with dosages of 1 g of either Ca-DTPA (Trisodium calcium diethylenetriaminepentaacetate) or Zn-DTPA (Trisodium zinc diethylenetriaminepentaacetate) were undertaken at Los Alamos Occupational Medicine in three recent cases of wounds contaminated with metallic forms of Pu. All cases were finger punctures, and each chelation injection contained the same dosage of DTPA. One subject was treated only once, while the other two received multiple injections. Additional measurements of wound, urine, and excised tissues were taken for one of the cases. These additional measurements served to improve the estimate of the efficacy of the chelation treatment. The efficacy of the chelation treatments was compared for the three cases. Results were interpreted using models, and useful heuristics for estimating the intake amount and final committed doses were presented. In spite of significant differences in the treatments and in the estimated intake amounts and doses amongst the three cases, a difference of four orders of magnitude was observed between the highest excretion data point and the values observed at about 100 d for all cases. Differences between efficacies of Zn-DTPA and Ca-DTPA could not be observed in this study. An efficacy factor of about 50 was observed for a chelation treatment, which was administered at about 1.5 y after the incident, though the corresponding averted dose was very small (LA-UR 09-02934).