10-24 



The time frame for trace metals reaching their ultimate r(?s- 

 positories in Iiong Island Sound then will be determined by the effici- 

 ency of burial of the trace metal-rich components deep in the sediment 

 column out of the domain of surficial resuspension and redistribution. 

 This burial is principally affected by deep burrowing organisms such as 

 the Crustacea. Documentation comes from Benninger and Aller (1979) 

 using plutonium as the man-made tracer (injected into the environment 



primarily in 1962 with secondary injections of smaller magnitude since 



210 

 then) and Pb as the steady-state tracer. Table 10-3 is taken from their 



work and shows that sediments in the deeper parts of Long Island Sound 



have a larger standing crop of both of the nuclides than the sediments 



in the shallow area, principally due to transfer to greater depths in 



the sediment column. This implies that the deeper part of the basin is 



the dominant repository for trace metals introduced into the Sound 



because of deeper biological reworking. 



TRACE METALS IN ORGANISMS 



Observed Trace Metal Distributions in Mussels and Oysters 

 from Long Island Sound 



Mussels and oysters (epifauna) are filter feeders which attach 

 to hard surfaces. Their isolation from the sediment means that their 

 trace-metal compositions are likely to be reflective, primarily, of the 

 suspended material in the water. The extent to which organisms more 

 intimately associated with the sediment (infauna) also reflect the 

 suspendable material can only be established by a comparison between 

 these infaunal organisms and the hard substrate species like the oysters 

 and the mussels. In this section, therefore, the data available on 

 trace-metal concentrations in mussels and oysters from the Connecticut 

 shore are reviewed. 



