700 
sludge would not alter this conclusion that the water column could 
safely receive the sludge. It may, however, have implications 
regarding seafloor impacts. 
After water column dilution, iron, lead, zinc, chromium, and 
PCB's would be expected to occur at detectably-elevated concentra- 
tions within the mixed layer downstream from the 106-Mile site. 
About 500 km southwest of the site and offshore from Cape Hatteras, 
the sludge would be further diluted by entrainment into the Gulf 
Stream (O'Connor et al., in press e). This dilution would erase 
the chemical signature of sludge. No sludge component which would 
be expected to occur in the water column are likely to be of bio- 
logical consequence. This applies to all the exposed organisms, 
including those of commercial and recreational value. The plankton 
community in the open ocean is more sensitive to contamination than 
those from coastal areas. Nevertheless, the sludge dilution should 
be adequate to prevent local effects (O'Connor et al., in press e). 
Commercial resources that may be exposed are squid, tilefish, and 
lobster (year-round residents near the edge of the shelf) and shad, 
mackerel, sea bass, scup, and flounder (winter residents near the 
edge of the shelf break. The exposure of any of these species 
would be limited, because they are not restricted to the upper 
mixed layer. During winter, dilutions can be expected to be ten 
times greater than during the summer months due to the lack of 
thermal stratification. 
Even without sludge dewatering, benthic effects from disposal 
are possible. A seafloor manifestation of sludge could be created 
by the settleable components of sludge, if such sludge components 
were to settle at a rate of at least 10 m/day, thus reaching the 
deep-sea floor in 200 days or less (O'Connor et al., in press e). 
For sludges diluted by a factor of 500, about 20% was observed to 
settle at 10 m/day or faster. At smaller dilutions, more than 20% 
settled at faster rates because of flocculation. Sludge delivered 
at the 106-Mile site could be dumped with an initial dilution 
