MEASUREMENT OF BASE-LINE ATMOSPHERIC PU-239, PU-240 AND AM-241 IN THEVICINITY OF THE WASTE ISOLATION PILOT-PLANT

Measurements of aerosol Pu-239,Pu-240 and Am-241 activity concentratio ns have been made in the vicinity of the Waste Isolation Pilot Plant ( WIPP). Samples for total suspended particulate matter (TSP) and partic ulate matter less than or equal to 10+/-2 mu m aerodynamic diameter (P M10) collected on 20x25-cm(2) glass fiber filters at a site approximat ely 1 km from the WIPP exhaust shaft. Samples for both TSP and PM10 we re collected concurrently at 5 m above ground level. Other concurrent PM10 samples were also collected at 2 m above ground level. At the 5-m level, approximately 50% of the mass and the Pu-239,Pu-240 and Am-241 activities in the TSP are contained in the PM10 fraction. Comparison of the PM10 data from 2- and 5-m levels indicates that Pu-239,Pu-240 a ctivity concentrations at the 2-m elevation are approximately 50% high er than the activity concentrations at the 5-m elevation. The overall average of the activity ratio between Am-241 and Pu-239,Pu-240 is 0.40 +/-0.02 which is in good agreement with other published values.