GB Toxicity in Mice Exposed for 20 to 720 Min

摘要

Most of the historical data for the toxicity of GB was collected for exposure times less than 10 minutes in an attempt to establish the utility of and defense against this agent in offensive front line use. However, information concerning the toxicity of GB (and other nerve agents) for exposures of 1 to 12 hours is critical for personnel functioning for long periods in collective protection; for flight crews waiting for action in areas of low-level contamination; for aircrews transporting previously contaminated material in cargo bays; for hospital staff who must work with contaminated victims; and for all personnel who have been attacked, are dressed in Individual Protective Equipment, and need to know when, and if, it is safe to take off these cumbersome garments. The data presented for the toxicity of GB to mice for exposures of 20 minutes to 12 hours are intended to form part of an international, collaborative, multi-species effort to establish toxicity estimates for humans for longer exposure times. LCt(sub 50) values of 430, 538, 899, 1209 and 2214 mg/min/cu m were obtained from mice for 20-, 60-, 180-, 360- and 720-minute exposures to GB, respectively. The 20- and 60-minute data fit well with historical data for 20-second to 30-minute exposures. The data for longer exposures do not follow either Haber's rule (LCt(sub 50) = CT) or the toxic load expression involving CT previously established for 10-second to 30- minute exposures. The experimental data appear to indicate a threshold exposure concentration near 3 mg/cu m for the LC(sub 50) for exposures up to 12 hours. (7 tables, 3 figures, 13 refs.).