10,000 r 



1,000 



O 



LU 



>- 



O 



6 



100 - 



Newport Bridge 



K. 



Iron 



T A-', -r ..''V 





••'k T 



.-.-P- 



.^ • 



-J 





Manganese J___I 



10 p 



^j.— - 



E^ Zinc 



? iv . 



f 



^rS' 



T •'•"7 : 



i i . 





-k. 



'''ill' 



NOV 

 1966 



JAN. 

 1967 



MAR. 



MAY 



JULY 



SEPT. 



NOV. 



Figure 16. — Concentrations of iron, manganese, and zinc in sediment collected monthly from the Newport Bridge station 

 (salinity range, 25 - 34 p.p.t.) in the Newport River estuary. Each value represents the mean and standard deviation of 

 10 samples. 



VARIATION OF ELEMENTAL CONTENT IN 

 MARINE POLYCHAETOUS WORMS 



Ford A. Cross, Marianne B. Murdoch, and 

 John A. Baker, Jr. 



Research in radioecology has been directed 

 recently towards describing the cycling of not 

 only radionuclides, but also their stable com- 

 ponents, in aquatic ecosystems. This approach 

 allows the use of the specific activity concept 

 which may have application in regulating the 

 rate at which specific radionuclides can be 

 discharged into the marine environment. Also, 



knowledge of the concentrations of stable ele- 

 ments in both aquatic biota and water can be 

 used to predict the maximum concentrations of 

 radioactivity in biota if the stable and radio- 

 active species are in the same chemical state. 

 Much information can be found on the con- 

 centrations of trace elements in the major 

 phyla of marine organisms; very little is 

 known, however, concerning the concentrations 

 of these elements in polychaetes. In addition, 

 the role that polychaetes play in the accumu- 

 lation and redistribution of trace metals, both 

 radioactive and stable, within an estuary has 

 not been evaluated. Therefore, we recently 



31 



