Sewer sludge and dredge spoils dumped in the New York Bight contain 

 especially high concentrations of lead, chromium, copper and other common 

 industrial heavy metals. Table 8 (on page 60) compares concentrations of 

 some heavy metals found in sludges to natural levels in sea water and 

 to concentrations toxic to marine life. 



In determining the reactivity of heavy metals, their uptake in the 

 food chain, and their toxic potential, knowledge of the relative concentra- 

 tions in the sediments is necessary, hut not sufficient. Knowledge of the 

 physical status of these metals following disposal is necessary. Do these 

 metals exist in ionic form? Do they form organic ion complexes? Do they 

 exist as relatively inert insoluble compounds in the bottom sediments? 

 Are they included as colloidal suspensions in the water column? What are 

 the mechanisms, or conditions, that may result in their transfer, deposi- 

 tion or reactivity? Technology has not provided answers to these questions. 



Completed studies by the SUNY-SB and the SHL have helped determine the 

 relative concentrations of heavy metals in the sediments of the Bight dump- 

 ing grounds. Both studies found that sediments contained heavy metals in 

 much greater concentrations than in other nonspoil areas. Higher heavy 

 metal concentrations were found by SHL at stations north of both dumping 

 sites and south, along the length of the Hudson Canyon, suggesting possi- 

 ble spreading of the wastes. Concentrations of certain heavy metals given 

 in the SHL report (Tables 2-2, 5-10 and 5-17) show large, temporal, wi thin- 

 station, variations, suggesting a patchy distribution of sediments and a 

 heterogeneous distribution of heavy metals within the disposal areas. 

 Neither the SHL nor the SUNY-SB reports account for within-station varia- 

 tions of heavy metals in their analysis (SAC, 1972), although the SUNY-SB 

 report presents statistics on selected samples. 



SHL study concluded that the observed buildup of heavy metals is close- 

 ly associated with waste disposal in the area. This is not a fully sup- 

 ported conclusion. It cannot be denied that ocean dumping is primarily 

 responsible for the high levels of heavy metals in the sediments of the 

 dumping sites relative to other shelf sediments not covered by waste 

 materials, but a buildup (in relative concentration) of heavy metals with- 

 in the dumping grounds is not apparent from the SHL data. In fact the 

 SUNY-SB study (Gross et al, 1970) shows that a diminution rather than a 

 buildup, of heavy metals such as chromium, lead, silver and copper in the 

 sediments of the dumping grounds has occurred relative to the parent waste 

 material (inner harbor sediments and sewage sludge). The mechanisms for 

 the diminution are not demonstrated and it is possible that a transfer 

 occurs by lateral loss due to sediment transport, mixing with shelf sedi- 

 ments, or flux to overlying water. 



The possibility that heavy metals enter the marine food chain is 

 important, since the apparent decrease of heavy metals from these deposits 

 is unexplained. However, Gross, et al., (.1971) concluded that because of 

 the relatively low extraction efficiency with hot hydrochloric acid, it 

 seems unlikely that the metals would leach from the waste deposits and 

 enter the overlying water. This was disputed by the SAC review (SAC, 



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