No abstract

No abstract

Tidal cycle budgets for June, July, August, September, and November 1979 showed that inorganic N was imported to the wetland from the Delaware River early in the growing season and exported late in the growing season. Nitrate and organic nitrogen were imported following macrophyte dieback. Reactive P was never lost from the marsh, and was actually imported on three dates. Total P was imported in July, September, and November, but otherwise exported. The metal present in the lowest concentration, Cd, was always exported; Ni, Cu, and Zn were imported on all but one date. Lead was imported late in the growing season and following macrophyte dieback. Nonpoint‐source inputs of Pb exceeded inputs from tidal waters.The vegetation played a major role in the retention of N, P, Cu, Pb, and Ni entering the wetland through the growing season. The litter retained significant quantities of all heavy metals following macrophyte dieback, but it serves only as a temporary storage vehicle because rates of decomposition are high. The soil showed no definite seasonal pattern of nutrient or heavy metal retention. Elevated Pb levels occurred at sites near storm drains reflecting rapid sedimentation and retention of this metal as storm waters entered the wetland. It is concluded that freshwater tidal wetlands play an important seasonal role in reducing nutrient and heavy metal loading in the upper Delware River estuary.

P r i t c h a r d , J. A. C a r t e r Oak Ridge National Laboratory Oak Ridge, Tennessee 37830 ABSTRACT The method uses b a s i c anion r e s i n t o adsorb plutonium and uranium from 7-8 8 €NOJ s o l u t i o n s containing dissolved s p e n t r e a c t o r f u e l s . A f t e r e q u i l i b r a t i n g t h e r e s i n with t h e s o l u t i o n , a s i n g l e bead is used t o determine t h e i s o t o p i c composition of plutonium and uranium on s a m p l e s i z e s as small as 10 t o 10 g of each element per bead. I s o t o p i c measurements are e s s e n t i a l l y f r e e of i s o b a r i c i n t e r f e r e n c e s and f i s s i o n product contamination i n t h e mass spectrometer is eliminated. A very small a l i q u o t -6 of d i s s o l v e r s o l u t i o n containing 10 g of U and g of Pu i s s u f f i c i e n t sample f o r chemically preparing s e v e r a l r e s i n beads. A single prepared bead is loaded onto a rhenium filament and analyzed in a two-stage m a s s spectrometer using pulse counting f o r ion d e t e c t i o n t o o b t a i n t h e high s e n s i t i v i t y required. t o p i c abundances, can b e determined by i s o t o p e d i l u t i o n . Other areas where t h e method may be u s e f u l a r e : and f o r t r a c e d e t e c t i o n of contamination on r e a c t o r p a r t s . -9 -10 T o t a l q u a n t i t y of t h e elements, i n a d d i t i o n t o isoin plutonium production, isotope s e p a r a t i o n s , 563CopyrightO1974 by Marcel Dekker, Inc. All Rights Reserved. Neither this work nor any port may be reproduced or transmitted in any form or by any means, electronic or mechanicol, including photocopying, microfilming, and recording, or by any information storage ond retrieval system, without permission in writing from the publisher.

No abstract