WHOLE-BODY EXPOSURES TO A PHOSPHORIC-ACIDS AEROSOL .1. SPONTANEOUS ACTIVITY EFFECTS IN WILD RODENT AND AVIAN SPECIES

Two inhalation-chamber studies were conducted to assess acute (2-h out -of-chamber) and subacute (less-than-or-equal-to 6 d postexposure) spo ntaneous activity effects of whole-body phosphoric acids aerosol expos ure(s) in black-tailed prairie dogs (Cynomys ludovicianus) and rock do ves (Columba livia). The aerosol was generated using a red phosphorus/ butyl rubber (RP/BR) mixture under development as a military obscurant . Each study involved (1) 3 RP/BR target concentration groups [0.0 (co ntrols), 1.0, and 4.0 mg/L], (2) 24 prairie dogs or rock doves (8/grou p), with gender included as a factor (3) a successive 3-phase paradigm (2 d preexposure, 4 and 2 d of about 80 min/d exposures to RP/BR for prairie dogs and rock doves, respectively; and 6 d postexposure), and (4) infrared detection of the rodents'/birds' home-cage movements. In- chamber atmospheres were uniform and acceptable for all exposures; med ian aerosol mass concentrations ranged from 0.76 to 0.89 mg/L and 3.46 to 3.74 mg/L for the 1.0 and 4.0 mg/L groups, respectively, with medi an phosphoric acid (H3PO4) readings of between 67.2 and 74.3%; median particles were less-than-or-equal-to 0.85 mum. Mortality was negligibl e; no prairie dogs died, but 1 male rock dove died on d 3 postexposure to two 4.0 mg/L target concentrations of RP/BR aerosol. Group x sessi on interactions were significant for the acute activity counts of both species. The acute mean ambulatory (e.g., walking) counts of prairie dogs and the acute mean ambulatory and horizontal (e.g., preening) cou nts of rock doves exposed to 4.0 mg/L RP/BR aerosol were relatively le ss than those of the other groups after the first 2 or 1 exposures, re spectively Nevertheless, acute session means for all groups approximat ed or exceeded the 23 h/d activity measured during the pre- and postex posure phases-data indicating that chamber confinement caused a tempor ary, sharp increase in activity for both species irrespective of RP/BR aerosol concentrations. No RP/BR concentration-related, subacute shif ts in the activity of the rodents/birds were observed