Description: Progress is reported on work conducted at the Nevada Test Site under the auspices of the Nevada Applied Ecology Group, Office of Effects Evaluation, USAEC Nevada Operations Office, Las Vegas. Nevada. Included are data on some ecological attributes of the vegetation within thc fenced portion of the Project 57 fallout pattern in Area 13. Also included are some preliminary data on the / sup 239/-240/Pu and /sup 241/Am in samples of vegetation collected in conjunction with the soil sampling program. Prominent shrub and grass species in the fallout pattern of Area 13 include Artemisia spinescens, Atriplex canescens, Atriplex confertifolia, Eurotia lanata, Grayia spinosa, Kochia americana, Lycium andersonii, and Oryzopsis hymenoides. Individual or co-dominant species distinguished local association pattarns of varied size within the fenced study area. Vegetation cover estimates in sample study plots ranged from 12.8 to 25.3 percent. Shrub densities ranged from 11.2 x 10/sup 3/ to 17.9 x 10/sup 3/ plants per hectare, and the standing shrub biomass ranged from 1592 to 4255 kilograms per hectare (0.7 to 1.9 tons per acre). Preliminary results showed rather uniform distributions of /sup 239-240/Pu and /sup 241/Am among indiividual samples of the same plant species collected within an intensive study plot. However, there was considerable variation in the contamination levels between different species, presumably from superficial entrapment of resuspended particulate material. Concentrations in Eurotia lanata were three to five times higher than in other species sampled from the same study site. The /sup 239-240/ Pu and /sup 241/Am generally tended to decrease in samples of vegetation collected at increasing distances from ground zero, but there were poor correlations between vegetation and soil /sup 239-240/Pu concertrations in isopleth strat within the fenced grazing area. Results showed inconsistencies in the Pu/Am ratios for vegettion and soil. Lower ratios found in vegetation samples indicate ...
Date: November 1, 1973
Creator: Romney, E.M.; Wallace, A.; Gilbert, R.O.; Bamberg, S.A.; Childress, J.D.; Kinnear, J.E. et al.
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Partner: UNT Libraries Government Documents Department