MIGRATION OF PLUTONIUM FROM FRESHWATER ECOSYSTEMS 627 



7. Emergent insects (those with emerging adult stages). 



8. Gastropods. 



9. Goldfish (anthropogenic ally introduced). 



10. Sediments (down to 10 cm and including organic floe generated from decom- 

 posing plant material). 



Water itself is not considered as a compartment, but the particulate contents 

 contained by the water mass are accounted for in other compartments. Suspended 

 particles greater than 0.1 jum (seston) are fractioned by weight into inert particles and 

 algae on the basis of microscopic inspection and dry weight— ash weight comparisons. 

 Weiglits of the sestonic algae, which are mostly diatoms, are added to the nonfilamentous 

 algae compartment, and weights of inert particles are placed with the sediments. Particles 



I LABORATORY 



2 4 6 8 10 

 Kilometers 



Fig. 1 Map of Hanford site showing location and detail of U-Pond. 



