levels in sediment and water (Table 2). Cladophora and Lemna contain
approximately the same level of 238py, which {ts the highest seen forall
biota from the watershed.
Lemna sampled from South Pond is lower in 238py
activity than that collected from the canal which reflects the differences in
activities between the two bodies of water (Table 3), It is suspected that
the roots of Lemna which are suspended tn the water column would be a
route for plutonium uptake as it is for nutrients. However, a more plausible
explanation at this time is again surface adsorption due to the high surface
to volume ratio of the small plants.
an indication of plutonium translocation within the plant. Comparing the
levels of plutonium in the canal sediment (Table 2), with the activity in the
grass (C.F.seq), it appears that little transfer has occurred from the sediGrass has higher 238Pu activity than the emergent,
Typha, but the same C.F..oq.
Typha also rooted in the canal sediment,
shows little active uptake above the roots,
However, it appears that the’
stems have more 238pu activity than the spikes or flowering parts (Table 6).
The C.F .43,9 for 238pu in Typha from the canal is one to two ordersof
magnitude lower than the C.F.,9 for the Typha from the Hanford waste
pond (Emery and Klopfer, 1976).
SUMMARY AND CONCLUSIONS
The aquatic plants from the Great Miami River have higher levels of 238py
downstream of Mound Laboratory than upstream, Cladophora concentrates
plutonium more than the macrophytes, Potamogeton and Myriophyllum, which
exhibit similar but lower total plutonium activities,
Cladophora and macrophytes, Lemna and Typha, from the canal and ponds
have elevated levels of 238Pu which is attributed to the higher levels of
238py in the sediments and water of the canal and ponds. Cladophora from
the canal has higher total 238Pu activity than Cladophora from the adjacent
river; however, the canal algae have lower concentration factors, This may
be indicating a saturation of surface sorption sites as opposed to active
uptake by the plants.
Typha and grass (grown in a dry canal bed) demonstrate that there is very
little translocation of 238pu above the roots. Some differentiation, however, exists in Typha with stems having slightly higher 238pu activities
than spikes.
Primary producers in an aquatic ecosystem are capable of scavenging and
accumulating plutonium from the surrounding water and sedimentsto levels
which are the highest observed in all biota,
514
the consumption of waterfowl.
ACKNOWLEDGMENTS
The authors wish to thank W, H, Westendorf, D. G. Carfagno and R.
Robinson of Mound Laboratory for their cooperation.
Grass is included in Table 6 with aquatic plants because it was growing in
the sediment of a dry canal bed. Analysis of the plants minus roots gives
ment to the stems.
consideration in the study within aquatic food chains, but it may be significant in providing an additional and possibly more direct route to man
via
Not only is this an important